WO2012061595A1 - Method of system for increasing the reliability and accuracy of location estimation in a hybrid positioning system - Google Patents

Method of system for increasing the reliability and accuracy of location estimation in a hybrid positioning system Download PDF

Info

Publication number
WO2012061595A1
WO2012061595A1 PCT/US2011/059139 US2011059139W WO2012061595A1 WO 2012061595 A1 WO2012061595 A1 WO 2012061595A1 US 2011059139 W US2011059139 W US 2011059139W WO 2012061595 A1 WO2012061595 A1 WO 2012061595A1
Authority
WO
WIPO (PCT)
Prior art keywords
sps
initial position
positioning system
indicator
position estimate
Prior art date
Application number
PCT/US2011/059139
Other languages
French (fr)
Inventor
Farshid Alizadeh-Shabdiz
Mohammad A. Heidari
Original Assignee
Skyhook Wireless Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Skyhook Wireless Inc. filed Critical Skyhook Wireless Inc.
Priority to JP2013537820A priority Critical patent/JP2014501912A/en
Priority to EP11838809.9A priority patent/EP2635915B1/en
Priority to KR1020137014037A priority patent/KR101972606B1/en
Publication of WO2012061595A1 publication Critical patent/WO2012061595A1/en

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/42Determining position
    • G01S19/48Determining position by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G01S5/0257Hybrid positioning
    • G01S5/0263Hybrid positioning by combining or switching between positions derived from two or more separate positioning systems

Definitions

  • the invention generally relates to hybrid positioning and more specifically, describes new methods to assess the quality of a reported location from specific source of location to be used for hybrid positioning.
  • Parents wish to keep track of their children, supervisors need to track the locations of the company's delivery vehicles, and a business traveler looks to find the nearest pharmacy to pick up a prescription. All of these examples require an individual to know his own current location or the location of someone else. To date, we all rely on asking for directions, calling someone to ask their whereabouts or having workers check-in from time to time to report their positions.
  • Location-based services are an emerging area of mobile applications that leverage the ability of new devices to calculate their current geographic positions and report them to a user or to a service. Examples of these services range from obtaining local weather, traffic updates and driving directions to child trackers, buddy finders and urban concierge services.
  • These new location-sensitive devices rely on a variety of technologies that all use the same general concept. By measuring radio signals originating from known reference points, these devices can mathematically calculate the user's position relative to these reference points.
  • Each of these approaches has its strengths and weaknesses depending upon the nature of the signals and measurements, and the positioning algorithms employed.
  • GPS Global Positioning System
  • a user equipped with a GPS receiver can estimate his three-dimensional position (latitude, longitude, and altitude) anywhere at any time within several meters of the true location as long as the receiver can see enough of the sky to have four or more satellites "in view.”
  • Cellular carriers have used signals originating from and received at cell towers to determine a user's or a mobile device's location.
  • Assisted GPS (“AGPS") is another model that combines both GPS and cellular tower techniques to estimate the locations of mobile users who may be indoors and must cope with attenuation of GPS signals on account of sky blockage.
  • the cellular network attempts to help a GPS receiver improve its signal reception by transmitting information about the satellite positions, their clock offsets, a precise estimate of the current time, and a rough location of the user based on the location of cell towers. No distinction is made in what follows between GPS and AGPS.
  • Satellite-based Positioning System SPS
  • GLONASS Globalstar Satellite-based Positioning System
  • Galileo European system
  • All such systems are referred to herein as SPS.
  • GPS, GLONASS and Galileo are all based on the same basic idea of trilateration, i.e., estimating a position on the basis of measurements of ranges to the satellites whose positions are known. In each case, the satellites transmit the values of certain parameters which allow the receiver to compute the satellite position at a specific instant.
  • the ranges to satellites from a receiver are measured in terms of the transit times of the signals. These range measurements can contain a common bias due to the lack of synchronization between the satellite and receiver (user device) clocks, and are referred to as pseudoranges.
  • the lack of synchronization between the satellite clock and the receiver (user device) clock can result in a difference between the receiver clock and the satellite clock, which is referred to as internal SPS receiver clock bias or receiver clock bias, here.
  • internal SPS receiver clock bias or receiver clock bias In order to estimate a three dimensional position there is a need for four satellites to estimate receiver clock bias along with three dimensional measurements. Additional measurements from each satellite correspond to pseudorange rates in the form of Doppler frequency.
  • References below to raw SPS measurements are intended generally to mean pseudoranges and Doppler frequency measurements.
  • References to SPS data are intended generally to mean data broadcast by the satellites.
  • References to an SPS equation are intended to mean a mathematical equation relating the measurements and data from a satellite to the position and velocity
  • WLAN-based positioning is a technology which uses WLAN access points to determine the location of mobile users.
  • PlaceLab www.placelab.com, a project sponsored by Microsoft and Intel
  • the University of California San Diego ActiveCampus project (ActiveCampus - Sustaining Educational Communities through Mobile Technology, technical report #CS2002- 0714); and the MIT campus-wide location system.
  • WiFi Positioning System is a product of Skyhook Wireless, Inc.
  • a method includes determining initial position estimates of a device using a satellite positioning system and also non-satellite positioning systems. The method, then, collects relevant information regarding each source of location and assigns weights for each source of location.
  • a method for determining the position of a device in a hybrid positioning system comprises analyzing signals from at least two of a satellite positioning system ("SPS"), a Wi-Fi positioning system, and a cell positioning system (“CPS”), determining for each of the at least two of the SPS, Wi-Fi positioning system, and CPS, a corresponding initial position estimate of the device and at least one corresponding parameter, and selecting one of the corresponding initial position estimates as a final position estimate of the device based on at least one of a history of previously reported positions, the at least one corresponding SPS parameter, the at least one corresponding Wi-Fi positioning system parameter, and the at least one corresponding CPS parameter.
  • SPS satellite positioning system
  • CPS cell positioning system
  • signals from a satellite positioning system, a Wi-Fi positioning system, and a cell positioning system are analyzed by the device.
  • the device determines a corresponding initial position estimate and corresponding parameters and selects one of the corresponding initial position estimates as the final position of the device based the history of previously positions or the corresponding parameters.
  • Fig. 1 illustrates a mobile device receiving signals from SPS satellites, WPS beacons, and CPS towers.
  • Fig. 2 illustrates a process for collecting relevant parameters of each location system (SPS, WPS, and CPS) and use of an algorithm implemented in a mobile device for switching.
  • Fig. 3 illustrates a process for collecting relevant parameters of each location system (SPS, WPS, and CPS) and use of an algorithm implemented in a mobile device for switching and a reference database.
  • FIG. 4 illustrates a method of location estimation according to aspects of the present invention.
  • Fig. 5 illustrates a method of determining the type of environment and the quality of the location estimate for a satellite position system.
  • a hybrid positioning system refers to a positioning system for device location, which itself consists of more than one individual positioning system (or "source of location").
  • the hybrid positioning system can be defined as a system using final positions of different sources of locations as initial positions.
  • the hybrid positioning system can selects or combine the initial locations and generates a position estimate based on observations by more than one source of location.
  • the hybrid system combines observations from several separate positioning systems and provides one position estimate of the device.
  • Each individual positioning system is able to detect a set of signal information from each of the system's signal sources, herein called “observables”.
  • the hybrid positioning system selects a source of location or a combination of different sources of locations and reports its final location to the user.
  • embodiments of the invention use different observables at the receiver side to assess the quality of different sources of locations.
  • This disclosure discusses methods to be used to select the best location. It also discusses methods to select the best location while reducing power consumption of a device. This can be achieved, for example, by changing the scanning rate of the device.
  • Embodiments of the invention achieve better accuracy, better availability, faster time to fix (which includes time to first fix), and less power consumption for a device relative to known methods.
  • implementations of the hybrid positioning system include more than one positioning system or generates position estimates based on more than one source of location.
  • the individual positioning systems can use a method particular to that system to estimate a position of a device.
  • a hybrid positioning system includes, or receives information from, at least two of the following three positioning systems: (1) a satellite positioning system, which uses signals transmitted by satellites to locate the device, (2) a WiFi positioning system, which uses signals transmitted by WiFi access points to locate the device, and/or (3) a cell positioning system, which uses signals transmitted by cell towers to locate the device.
  • Fig. 1 illustrates a scenario in which a mobile device receives signals from SPS satellites, WPS beacons, and CPS towers.
  • the individual positioning systems within an embodiment of the hybrid positioning system are used in the hybrid decision-making when they satisfy certain performance criteria enforced by the hybrid positioning system.
  • the hybrid positioning system can enforce the individual positioning systems criteria to require accuracy better than a given threshold value in order to consider positioning estimates from the individual positioning systems in the switching algorithm. For example, the hybrid positioning system may decide to only use satellite locations when the number of satellites in view exceeding a certain threshold and reject otherwise.
  • Embodiments of the invention enable a hybrid positioning system to select a reported location from a specific positioning system.
  • the hybrid positioning system analyzes different observable parameters obtained by individual positioning systems and selects one of the estimated positions provided by the individual positioning systems.
  • the hybrid positioning system also analyzes different observable parameters by individual positioning systems to make a decision regarding enabling or disabling one or more available positioning systems and/or disabling corresponding devices in order to reduce the overall system power
  • the hybrid positioning system decides on which positioning system to use and how to report the final location of the device.
  • One goal of certain implementations of the invention is to increase performance of a hybrid positioning system. Better performance can mean better accuracy, better availability, faster time to fix, or better power consumption.
  • Performance can also be referred to as a combination of two or more of the accuracy, availability, accuracy, time to fix, power consumption as well.
  • the outcome of each source of location in certain circumstances is combined and the calculated location is reported to the user.
  • the quality of reported location for each source of location in hybrid positioning system is evaluated.
  • the quality of each source of location and its reported location is evaluated by analyzing the observable parameters at the receiver.
  • a high quality source of location is the one that shows strong signals and good positioning accuracy.
  • a bad quality source of location is the one that shows weak signals and poor positioning accuracy. It should be noted that for each source of location, the parameters to indicate the quality of positioning accuracy is different from other sources of location.
  • a hybrid positioning system can include two or more of an SPS, WPS, and/or CPS.
  • Each of these sources of locations might provide user locations independent of other sources of locations.
  • the hybrid positioning system might have access to locations obtained from all three sources, i.e. SPS, WPS, and CPS.
  • the hybrid positioning system can then analyze each source of location for the accuracy of its reported location. After assessing the quality of each source of location, the hybrid positioning system can select the best and most accurate location and report that to user as final location estimate.
  • Fig. 2 illustrates the process of collecting relevant parameters of each location system (SPS, WPS, and CPS) and sending the parameters to an algorithm
  • either source of reported location or the hybrid positioning system are enabled to cache the previous reported location for some interval of time.
  • a hybrid system might report a cached SPS location for 10 seconds before reporting no location or before switching to WPS location. If hybrid system decides that WPS location accuracy is much worse than SPS location, it can report the old SPS location for an extended interval of time, then start reporting WPS location.
  • the accuracy of the reported location deteriorates from SPS to WPS to CPS.
  • One technique for the selection of sources of location estimates based on availability of better-known sources of location is known by those having ordinary skill in the art as a waterfall switching algorithm.
  • Embodiments of the invention select between different sources of location estimates and report the best location according to a performance criterion rather than a predetermined preference.
  • a decision can be made to select and/or report position location estimate from a WPS even thought an estimate from an SPS location is available when the hybrid positioning system determined that the quality of the position estimate from the SPS is lower than that of the WPS.
  • each source of location i.e., individual positioning system
  • SPS The first source of location discussed herein is SPS, which relies on receiving satellite and measurement information from satellites at the receiver side.
  • SPS listens for satellite signals, receives, and processes them.
  • the received signals along with some other information passed to the SPS (e.g., via a network) could enable the receiver to calculate its location.
  • the principle used here is to know the exact location of the satellite and measure the distance of the satellite to the receiver.
  • the receiver solves a set of equations and calculates the location of the receiver.
  • the quality of the reported location in SPS is usually assessed through Horizontal Dilution of Precision (HDOP.) The smaller the HDOP value, the better the positioning accuracy.
  • Examples of SPS are GPS (Global Positioning System), Galileo, GLONASS, or Compass.
  • the elapsed time to obtain the fix (which is called time to fix or TTF) is used as an indicator of the quality of an estimated location.
  • TTF time to fix
  • fix comes quickly.
  • fix might take some time to arrive.
  • the hybrid position system can take advantage of this difference in TTF and assign a quality factor to SPS location.
  • elapsed time after fix (TAF) can also be used as an indicator of the quality of an SPS estimated location.
  • Time after fix refers to the duration of time that a fix has been continuously provided without a gap in time.
  • an SPS device can maintain its fix.
  • the device might not be able to maintain the fix. This results in small TAF values and indicates that device is in challenging environment for SPS.
  • implementations of the invention combine the above metrics and use the result as an indicator of the quality of an SPS estimated location.
  • the combination of TTF and TAF can be considered as another metric.
  • the proposed metric looks for "gaps" in time for consecutive fixes. So if SPS fixes are obtained and lost frequently, system decides that the SPS device is in challenging environment for SPS. For example, if SPS fix is lost for 5 seconds and a fix is provided after five seconds,then TTFfor the new fix is 5s. If we get subsequent fixes for the next 120s, then TAF is 120s. The combination of TTF and TAF, 5s to get the fix and continuous fixes for 120s, would indicated that there is no gap in acquiring SPS fixes and the quality of SPS location is likely to be very good.
  • Secondary measures are also employed to estimate the quality of an SPS location estimate, as follows.
  • the hybrid positioning system can use number of satellites used to calculate the SPS location as an indicator of type of environment. In open environments, the number of satellites used in a fix is generally large. On the other hand, in challenging environments for SPS, fixes are obtained with very few satellites, and fixes are maintained with few satellites.
  • the velocity of the device as determined by SPS can be used as a secondary measure of quality. In general, when the SPS velocity is relatively large, the SPS receiver is considered to be located in an open sky environment and its location is considered to be very accurate. For example, having SPS locations with reported velocity of 60mph would indicate that the device is in driving mode and hence likely to be outdoors and not indoors.
  • the number of satellites currently in view can be used as an indicator of the type of environment.
  • an SPS can receive signals from different satellites, and the number of satellites in view is large.
  • the number of satellites in view is low.
  • number of satellites in view refers to number of satellites from which the SPS receiver receives signal.
  • the velocity in this discussion can come from SPS or other sources of location such as Wi-Fi positioning system. It can also come from other sensors on the device or working with the device. For example, the velocity can come from speedometer of a car which is connected to the device. Same discussion applies to bearing.
  • the hybrid positioning system can use the variations in positions provided by SPS in specified time interval to measure the quality of SPS location. For example, variations measures such as variance, standard deviation, range, interquartile range, etc. might be used to gauge the variation of SPS position for 30 seconds of reporting location.
  • the hybrid positioning system can use variations of other parameters related to SPS position in order to assess the quality of SPS reported location. The changes should follow a logical order of changes for a device. For example, the hybrid positioning system can use variations in velocity, bearing, and number of satellites used to derive the SPS location which all are reported by SPS. In such cases, huge jumps and variations in velocity or bearing of the device would indicate that SPS-provided locations might be of lower quality and/or the environment has changed.
  • the hybrid positioning system can also use the variation of combination of all the above parameters in order to assess the quality of the SPS location.
  • SPS provided location moves slowly from one point to the other point.
  • these changes can also be correlated with velocity of the vehicle and the integrity of the provided solution can be checked.
  • the displacements in subsequent locations are according to the signals received from satellites and they follow the physical rules governing the device. For example, for a device moving with 10 m/s velocity, the location of the device from one point in time to a second after that time should only change 10 m.
  • the hybrid positioning system based on realistic values for velocity and bearing and previous SPS location, can reject a new reported SPS location, if the new location is much further than anticipated location. This can provide integrity on the reported location and avoid large jumps in location which are not feasible.
  • WiFi positioning generally relies on received signals from different WiFi beacon devices. After receiving the signals from a wireless beacon or WiFi access point (AP) device, it might calculate the received power for all visible devices. WiFi Positioning then compares this information against a database of known AP devices and decides on the location of the user.
  • WiFi Positioning is generally less accurate than SPS, but it has been shown that in challenging environments for SPS, WiFi Positioning can be more accurate. Such challenging environments might include urban canyons (a canyon-like effect created by surrounding buildings) and indoor environments. This disclosure discusses the possibility of detecting such cases and the type of environment. Based on such a conclusion, the hybrid positioning system selects the best possible location when both SPS and WiFi positioning are available.
  • the number of observed wireless beacons can be used as an indicator of type of environment.
  • a large number of wireless devices can indicate a challenging environment for SPS, such as indoors or in a dense urban environment. If an environment is challenging for SPS, it might take longer to acquire a fix, and the accuracy of the fix might be lower. This might indicate that although both WiFi Positioning and SPS locations are available, the WiFi Positioning location might be more accurate.
  • the number of observed wireless devices typically follows a distribution where its mean is much larger than distribution of number of APs in open sky environments. This observation could indicate that the device is located in a dense urban environment, and its SPS location might not be as accurate as a WPS location, or SPS takes longer than normal to acquire a fix.
  • the quality of the location estimate returned from a WPS can be used as an indicator of the quality of WiFi Positioning location relative to other individual systems.
  • the relative quality of reported locations from a WPS and an SPS enables the hybrid system to make a better decision in reporting the final location. For example, a very good location obtained from WiFi Positioning could be more accurate than a location obtained from SPS with few satellites and poor quality of location.
  • Some implementations can use the maximum observed power from observed wireless devices as an indicator of the type of the environment that the device is working and relate it to the relative quality of SPS and the quality of WiFi Positioning location.
  • a wireless device when a wireless device is observed with high power, it could indicate that the receiver is located in indoor environments. Hence, it could be difficult to obtain a high quality SPS location, which translates to higher time to fix and lower accuracy. This could indicate that any SPS provided location does not represent the true location and suffers from large inaccuracies in the provided location.
  • the distance between an SPS-provided location and a WiFi Positioning- provided location can be used as a metric to select between two reported locations.
  • the two locations are very far from one another, it is assumed that the SPS location is more accurate due to the nature of SPS.
  • the hybrid positioning system should report the SPS location as its final location.
  • an aggregate of different parameters namely, number of satellites used in a fix, number of parameters in view, horizontal dilution of precision "HDOP," quality value of positioning in WiFi Positioning, inferred type of the environment the device is working in, number of WLAN devices used in WiFi Positioning, association information to an WLAN device, etc. are used to select the most accurate source of location.
  • the aggregate parameters can indicate the type of environment in which the receiver resides.
  • the system can use the aggregate information to select the best source among several location estimates.
  • Also disclosed herein are techniques to use the aforementioned information to reduce the power consumption of a mobile device, and, thereby, increase battery life.
  • several parameters namely, the number of WLAN devices used in WiFi Positioning and the maximum power observed from WLAN devices, are used to infer that the mobile deice is in a challenging environment for SPS.
  • an SPS present in the mobile device is instructed to remain off or the powering-on of the SPS is delayed.
  • the SPS can be powered-down if it does not acquire a fix within a designated period of time.
  • Such a technique can be employed when the mobile device starts a search for location.
  • the mobile device turns all devices on to find a location and presents the location result according to the waterfall switching algorithm.
  • the techniques disclosed herein propose to use the above parameters to delay turning-on the SPS hardware, or avoid powering-on the SPS all together in certain situations, in order to reduce power consumption by the mobile device.
  • the SPS hardware would be turned off if they do not acquire a fix within a predetermined period of time.
  • implementations of the invention propose to use association information between a WLAN AP and a mobile device, or any communication between a WiFi enabled device and a WLAN AP, as an indication of a high likelihood that the mobile device is indoor and/or is stationary. Such a determination can be used to delay powering-on SPS hardware in situations where it could not be completely confirmed that the device is indoors and/or is stationary. In the alternative, the SPS hardware can be left off or turned off if no location is acquired.
  • the techniques disclosed herein can be used to power-off SPS hardware within a mobile device when indications are detected that the mobile device is indoors or in a challenging environment for SPS.
  • the determination that the mobile device is indoors can be combined with the detection that the mobile device is not moving (or moving very slowly) to result in powering-off the SPS hardware. Therefore, when WPS hardware in the mobile device detects a low velocity, or that the user is stationary, the mobile device can power-off the SPS hardware to reduce power consumption.
  • the WPS hardware detects a moderate or higher velocity, the SPS hardware can be kept on.
  • the techniques disclosed herein also enable different methods to reduce the power consumption of mobile devices by dynamically changing the scan rate of the WiFi positioning system.
  • increased scan rates do not improve the accuracy of position estimates of the system and only consume more power.
  • some implementations determine if a scanning strategy is not optimized and adjust the scanning rate of the positioning engine to optimize the power consumption.
  • some embodiments optimize the tradeoff between positioning accuracy and power. Parameters such as association to a WLAN device, velocity of the mobile unit estimated from different sources of location, number of WLAN devices used in WiFi Positioning, maximum power observed from any WLAN device in range, and number of satellites in view can be used to change the scanning rate of the positioning algorithm.
  • Scanning rate is defined as the rate of scanning the surrounding environment and searching for related signals for each positioning system. Scanning rate is applicable to Wi-Fi Positioning Systems and CPS. SPS typical continuously search for signals from satellites and updates location estimate every second. However, Wi-Fi Positioning Systems can have different scanning rates, therefore the rate of turning on the wireless device and scanning the environment for near by wireless APs can be different from SPS. The scanning rate of the Wi-Fi Positioning System or CPS can be adjusted dynamically when the positioning algorithm switches from initial location state (one- shot location - for applications without a need to track the device) to tracking state (in which location is updated periodically).
  • the scanning rate for initial location state is lowered for power saving, while in tracking mode, because the user is concerned about receiving the best possible location, the scanning rate is increased to improve the accuracy.
  • the time during which a location request is active is used to optimize the scanning rate. For example, if a particular application calls for a location request at a known frequency (e.g., every 10 seconds), then the scanning rate of the positioning algorithm can be adjusted to scan and/or power-on particular location system only when a location estimate must be provided.
  • the techniques for reducing power consumption to increase battery life are disabled when the mobile device detects that it is connected to an external power source.
  • Fig. 3 illustrates the process of collecting relevant parameters of each location system (SPS, WPS, and CPS), using a reference database that may perform the initial position determination, and sending different parameters and the initial positions returned from the database to an algorithm implemented in a mobile device.
  • Fig. 4 illustrates a flow chart of a method for position estimation of a mobile device according to aspects of the present disclosure.
  • Signals from at least two positioning systems are analyzed in step 410.
  • signals from a satellite positioning system (“SPS"), a Wi-Fi positioning system, and a cell positioning system (“CPS”) are analyzed.
  • the method determines a corresponding initial position estimate for the SPS (420), for the Wi-Fi positioning system (430), and/or for the CPS (440), based on the analyzed signals.
  • the method in step 450 selects an initial position estimate as the final position estimate 460.
  • Fig. 5 illustrates a method for determining the type of environment using SPS parameters.
  • the bottom part of the figure there is an example of a challenging environment where there are a lot of instances where there is a fix and shortly after the fix is lost.
  • the following discussion is one example of a method for switching between different sources of locations (individual positioning systems).
  • the hybrid positioning system is assumed to have access to both an SPS and a WPS.
  • each source of location is capable of providing a location estimate.
  • one or both systems are unable to provide a location estimate.
  • the hybrid positioning system assesses the quality of the location estimates from each source of location. If location estimates from the SPS and the WPS are both available, the hybrid positioning system evaluates the accuracy of the location estimate provided by the SPS. For example, this can include analyzing the SPS parameters described above. If the quality of the location estimate provided by the SPS is high, the hybrid positioning system reports the SPS location immediately and does not evaluate the quality of the location estimate of the WPS. Otherwise, if the quality of the location estimate from the SPS is low, the hybrid positioning system analyzes the parameters of the WPS and compares the quality determinations.
  • the hybrid positioning system reports the location provided by the WPS. In cases where the position estimates from both the SPS and the WPS, the hybrid positioning system reports the SPS provided location. Finally, if only one source of location is able to provide an estimated location, then the hybrid positioning system reports the location from the only available system.
  • a neural network can be used to select between the sources of location.
  • This approach can be generalized when more sources are available.
  • the hybrid positioning system is trained with a comprehensive set of data. Each data set includes an SPS location estimate and its associated parameters, a WPS location estimate and its associated parameters, a CPS location estimate and its associated parameters, and the best final decision that could be made for that case.
  • the best final decision can be based on the known locations of the device when the training data set is assembled.
  • the parameters associated with SPS and WPS sources of location are those described above.
  • Parameters associated with CPS as a source of location include number of towers used for positioning, the relative power of the signals from the towers, the statistics of the signal power (e.g., variability, type of noise, etc.), and an error estimation associated with the towers, if available. After training the neural network with this dataset until it converges, the neural network determines a set of coefficients to be
  • Another technique for deciding which source(s) of location to use in a particular situation includes considering the history of previous location estimates. For example, assuming that both WPS and SPS estimates are available at the present moment and both have been available for a certain period of time, the hybrid positioning system can elect to use the SPS locations estimate as the present location. This is so because long-acquired SPS location estimates are believed to have more accurate locations than recent obtained location estimates. In other words, the time after obtaining a first location estimate in a current run of a hybrid positioning system can directly affect the decision as to which source of location is the most reliable and/or accurate. If a receiver is able to track SPS location estimates for more than several minutes, the location accuracy of that source is deemed to increase as time passes.
  • the hybrid positioning system can use different algorithms to select between different sources of location depending on how long the hybrid positioning system has been operational after initialization. For example, upon initialization and for a predetermined time thereafter, the system can employ the switching technique set forth above in Example 1 , and at operational times greater than the predetermined time employ the switching technique set forth above in Example 2.
  • the techniques and systems disclosed herein may be implemented as a computer program product for use with a computer system or computerized electronic device.
  • Such implementations may include a series of computer instructions, or logic, fixed either on a tangible medium, such as a computer readable medium (e.g., a diskette, CD-ROM, ROM, flash memory or other memory or fixed disk) or transmittable to a computer system or a device, via a modem or other interface device, such as a communications adapter connected to a network over a medium.
  • a computer readable medium e.g., a diskette, CD-ROM, ROM, flash memory or fixed disk
  • modem or other interface device such as a communications adapter connected to a network over a medium.
  • the medium may be either a tangible medium (e.g., optical or analog
  • the series of computer instructions embodies at least part of the functionality described herein with respect to the system. Those skilled in the art should appreciate that such computer instructions can be written in a number of programming languages for use with many computer architectures or operating systems and under different platforms.
  • Such instructions may be stored in any tangible memory device, such as semiconductor, magnetic, optical or other memory devices, and may be transmitted using any communications technology, such as optical, infrared, microwave, or other transmission technologies.
  • Such a computer program product may be distributed as a removable medium with accompanying printed or electronic documentation (e.g., shrink wrapped software), preloaded with a computer system (e.g., on system ROM or fixed disk), or distributed from a server or electronic bulletin board over the network (e.g., the Internet or World Wide Web).
  • a computer system e.g., on system ROM or fixed disk
  • a server or electronic bulletin board over the network (e.g., the Internet or World Wide Web).
  • some embodiments of the invention may be implemented as a combination of both software (e.g., a computer program product) and hardware. Still other embodiments of the invention are implemented as entirely hardware, or entirely software (e.g., a computer program product).
  • the techniques and systems disclosed herein can be used with a variety of mobile devices.
  • mobile telephones, smart phones, personal digital assistants, satellite positioning units (e.g., GPS devices), and/or mobile computing devices capable of receiving the signals discussed herein can be used in implementations of the invention.
  • the location estimate, expected error of the position estimate, and/or the probability values can be displayed on the mobile device and/or transmitted to other devices and/or computer systems.
  • the scope of the present invention is not limited to the above - described embodiments, but rather is defined by the appended claims; and that these claims will encompass modifications of and improvements to what has been described.

Abstract

Methods and systems of hybrid positioning are provided for increasing the reliability and accuracy of location estimation. According to embodiments of the invention, the quality of reported locations from specific sources of location is assessed. Satellite and non-satellite positioning systems provide initial positioning estimates. For each positioning system relevant information is collected and based on the collected information each system is assigned appropriate weight.

Description

METHOD OF AND SYSTEM FOR INCREASING THE RELIABILITY AND ACCURACY OF LOCATION ESTIMATION IN A HYBRID POSITIONING SYSTEM
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority under 35 U.S. C. § 119(e) to U.S. Provisional Application No. 61/409,643 filed November 3, 2010, entitled "Method Of And System For Increasing The Reliability And Accuracy Of Location Estimation In A Hybrid Positioning System," incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention generally relates to hybrid positioning and more specifically, describes new methods to assess the quality of a reported location from specific source of location to be used for hybrid positioning.
Description of the Related Art
[0003] In recent years the number of mobile computing devices has increased dramatically, creating the need for more advanced mobile and wireless services. Mobile email, walkie-talkie services, multi-player gaming and call-following are examples of how new applications are emerging for mobile devices. In addition, users are beginning to demand/seek applications that not only utilize their current location but also share that location information with others.
Parents wish to keep track of their children, supervisors need to track the locations of the company's delivery vehicles, and a business traveler looks to find the nearest pharmacy to pick up a prescription. All of these examples require an individual to know his own current location or the location of someone else. To date, we all rely on asking for directions, calling someone to ask their whereabouts or having workers check-in from time to time to report their positions.
[0004] Location-based services are an emerging area of mobile applications that leverage the ability of new devices to calculate their current geographic positions and report them to a user or to a service. Examples of these services range from obtaining local weather, traffic updates and driving directions to child trackers, buddy finders and urban concierge services. These new location-sensitive devices rely on a variety of technologies that all use the same general concept. By measuring radio signals originating from known reference points, these devices can mathematically calculate the user's position relative to these reference points. Each of these approaches has its strengths and weaknesses depending upon the nature of the signals and measurements, and the positioning algorithms employed.
[0005] The Navstar Global Positioning System ("GPS") operated by the US Government leverages about two-dozen orbiting satellites in medium-earth orbits as reference points. A user equipped with a GPS receiver can estimate his three-dimensional position (latitude, longitude, and altitude) anywhere at any time within several meters of the true location as long as the receiver can see enough of the sky to have four or more satellites "in view." Cellular carriers have used signals originating from and received at cell towers to determine a user's or a mobile device's location. Assisted GPS ("AGPS") is another model that combines both GPS and cellular tower techniques to estimate the locations of mobile users who may be indoors and must cope with attenuation of GPS signals on account of sky blockage. In this model, the cellular network attempts to help a GPS receiver improve its signal reception by transmitting information about the satellite positions, their clock offsets, a precise estimate of the current time, and a rough location of the user based on the location of cell towers. No distinction is made in what follows between GPS and AGPS.
[0006] All positioning systems using satellites as reference points are referred to herein as Satellite-based Positioning System ("SPS"). While GPS is the only operational SPS at this writing, other systems are under development or in planning. A Russian system called GLONASS and a European system called Galileo may become operational in the next few years. All such systems are referred to herein as SPS. GPS, GLONASS and Galileo are all based on the same basic idea of trilateration, i.e., estimating a position on the basis of measurements of ranges to the satellites whose positions are known. In each case, the satellites transmit the values of certain parameters which allow the receiver to compute the satellite position at a specific instant. The ranges to satellites from a receiver are measured in terms of the transit times of the signals. These range measurements can contain a common bias due to the lack of synchronization between the satellite and receiver (user device) clocks, and are referred to as pseudoranges. The lack of synchronization between the satellite clock and the receiver (user device) clock can result in a difference between the receiver clock and the satellite clock, which is referred to as internal SPS receiver clock bias or receiver clock bias, here. In order to estimate a three dimensional position there is a need for four satellites to estimate receiver clock bias along with three dimensional measurements. Additional measurements from each satellite correspond to pseudorange rates in the form of Doppler frequency. References below to raw SPS measurements are intended generally to mean pseudoranges and Doppler frequency measurements. References to SPS data are intended generally to mean data broadcast by the satellites. References to an SPS equation are intended to mean a mathematical equation relating the measurements and data from a satellite to the position and velocity of an SPS receiver.
[0007] WLAN-based positioning is a technology which uses WLAN access points to determine the location of mobile users. Metro-wide WLAN-based positioning systems have been explored by several research labs. The most important research efforts in this area have been conducted by the PlaceLab (www.placelab.com, a project sponsored by Microsoft and Intel); the University of California, San Diego ActiveCampus project (ActiveCampus - Sustaining Educational Communities through Mobile Technology, technical report #CS2002- 0714); and the MIT campus-wide location system. One example of a commercial metropolitan WLAN-based positioning system in the market at the time of this writing, is referred to herein as a WiFi Positioning System ("WPS") and is a product of Skyhook Wireless, Inc.
SUMMARY
[0008] Under one aspect of the invention, a method includes determining initial position estimates of a device using a satellite positioning system and also non-satellite positioning systems. The method, then, collects relevant information regarding each source of location and assigns weights for each source of location.
[0009] Under another aspect of the invention, a method for determining the position of a device in a hybrid positioning system is provided. The method comprises analyzing signals from at least two of a satellite positioning system ("SPS"), a Wi-Fi positioning system, and a cell positioning system ("CPS"), determining for each of the at least two of the SPS, Wi-Fi positioning system, and CPS, a corresponding initial position estimate of the device and at least one corresponding parameter, and selecting one of the corresponding initial position estimates as a final position estimate of the device based on at least one of a history of previously reported positions, the at least one corresponding SPS parameter, the at least one corresponding Wi-Fi positioning system parameter, and the at least one corresponding CPS parameter.
[0010] Under aspects of the invention, signals from a satellite positioning system, a Wi-Fi positioning system, and a cell positioning system are analyzed by the device. For each positioning system the device determines a corresponding initial position estimate and corresponding parameters and selects one of the corresponding initial position estimates as the final position of the device based the history of previously positions or the corresponding parameters. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] Fig. 1 illustrates a mobile device receiving signals from SPS satellites, WPS beacons, and CPS towers.
[0012] Fig. 2 illustrates a process for collecting relevant parameters of each location system (SPS, WPS, and CPS) and use of an algorithm implemented in a mobile device for switching.
[0013] Fig. 3 illustrates a process for collecting relevant parameters of each location system (SPS, WPS, and CPS) and use of an algorithm implemented in a mobile device for switching and a reference database.
[0014] Fig. 4 illustrates a method of location estimation according to aspects of the present invention.
[0015] Fig. 5 illustrates a method of determining the type of environment and the quality of the location estimate for a satellite position system.
DETAILED DESCRIPTION
[0016] Embodiments of a hybrid positioning system are disclosed herein. A hybrid positioning system refers to a positioning system for device location, which itself consists of more than one individual positioning system (or "source of location"). The hybrid positioning system can be defined as a system using final positions of different sources of locations as initial positions. The hybrid positioning system can selects or combine the initial locations and generates a position estimate based on observations by more than one source of location. The hybrid system combines observations from several separate positioning systems and provides one position estimate of the device. Each individual positioning system is able to detect a set of signal information from each of the system's signal sources, herein called "observables". Based on the possible observables of each reported location from different sources of location (i.e., different individual systems), the hybrid positioning system selects a source of location or a combination of different sources of locations and reports its final location to the user. In order to do so, embodiments of the invention use different observables at the receiver side to assess the quality of different sources of locations. This disclosure discusses methods to be used to select the best location. It also discusses methods to select the best location while reducing power consumption of a device. This can be achieved, for example, by changing the scanning rate of the device. Embodiments of the invention achieve better accuracy, better availability, faster time to fix (which includes time to first fix), and less power consumption for a device relative to known methods. [0017] As mentioned above, implementations of the hybrid positioning system include more than one positioning system or generates position estimates based on more than one source of location. The individual positioning systems can use a method particular to that system to estimate a position of a device. In some implementations, a hybrid positioning system includes, or receives information from, at least two of the following three positioning systems: (1) a satellite positioning system, which uses signals transmitted by satellites to locate the device, (2) a WiFi positioning system, which uses signals transmitted by WiFi access points to locate the device, and/or (3) a cell positioning system, which uses signals transmitted by cell towers to locate the device.
[0018] Fig. 1 illustrates a scenario in which a mobile device receives signals from SPS satellites, WPS beacons, and CPS towers. The individual positioning systems within an embodiment of the hybrid positioning system are used in the hybrid decision-making when they satisfy certain performance criteria enforced by the hybrid positioning system. The hybrid positioning system can enforce the individual positioning systems criteria to require accuracy better than a given threshold value in order to consider positioning estimates from the individual positioning systems in the switching algorithm. For example, the hybrid positioning system may decide to only use satellite locations when the number of satellites in view exceeding a certain threshold and reject otherwise.
[0019] Embodiments of the invention enable a hybrid positioning system to select a reported location from a specific positioning system. The hybrid positioning system analyzes different observable parameters obtained by individual positioning systems and selects one of the estimated positions provided by the individual positioning systems. The hybrid positioning system also analyzes different observable parameters by individual positioning systems to make a decision regarding enabling or disabling one or more available positioning systems and/or disabling corresponding devices in order to reduce the overall system power
consumption. The hybrid positioning system then decides on which positioning system to use and how to report the final location of the device. One goal of certain implementations of the invention is to increase performance of a hybrid positioning system. Better performance can mean better accuracy, better availability, faster time to fix, or better power consumption.
Performance can also be referred to as a combination of two or more of the accuracy, availability, accuracy, time to fix, power consumption as well.
[0020] In one embodiment, the outcome of each source of location in certain circumstances is combined and the calculated location is reported to the user. Under certain implementations, the quality of reported location for each source of location in hybrid positioning system is evaluated. The quality of each source of location and its reported location is evaluated by analyzing the observable parameters at the receiver. In certain circumstances, a high quality source of location is the one that shows strong signals and good positioning accuracy. On the other hand, a bad quality source of location is the one that shows weak signals and poor positioning accuracy. It should be noted that for each source of location, the parameters to indicate the quality of positioning accuracy is different from other sources of location.
[0021] As mentioned above, a hybrid positioning system can include two or more of an SPS, WPS, and/or CPS. Each of these sources of locations might provide user locations independent of other sources of locations. For example, at one instance of time, the hybrid positioning system might have access to locations obtained from all three sources, i.e. SPS, WPS, and CPS. The hybrid positioning system can then analyze each source of location for the accuracy of its reported location. After assessing the quality of each source of location, the hybrid positioning system can select the best and most accurate location and report that to user as final location estimate. Fig. 2 illustrates the process of collecting relevant parameters of each location system (SPS, WPS, and CPS) and sending the parameters to an algorithm
implemented in a mobile device.
[0022] In the above mentioned process, either source of reported location or the hybrid positioning system are enabled to cache the previous reported location for some interval of time. For example, a hybrid system might report a cached SPS location for 10 seconds before reporting no location or before switching to WPS location. If hybrid system decides that WPS location accuracy is much worse than SPS location, it can report the old SPS location for an extended interval of time, then start reporting WPS location.
[0023] Generally, the accuracy of the reported location deteriorates from SPS to WPS to CPS. One technique for the selection of sources of location estimates based on availability of better-known sources of location is known by those having ordinary skill in the art as a waterfall switching algorithm. Embodiments of the invention select between different sources of location estimates and report the best location according to a performance criterion rather than a predetermined preference. Thus, for example, a decision can be made to select and/or report position location estimate from a WPS even thought an estimate from an SPS location is available when the hybrid positioning system determined that the quality of the position estimate from the SPS is lower than that of the WPS.
[0024] Herein, are disclosed for each source of location (i.e., individual positioning system) parameters that are relevant to a switching algorithm that allows the hybrid positioning system to evaluate the quality of the reported location. The first source of location discussed herein is SPS, which relies on receiving satellite and measurement information from satellites at the receiver side. When started, an SPS listens for satellite signals, receives, and processes them. The received signals, along with some other information passed to the SPS (e.g., via a network) could enable the receiver to calculate its location. The principle used here is to know the exact location of the satellite and measure the distance of the satellite to the receiver. The receiver then solves a set of equations and calculates the location of the receiver. The quality of the reported location in SPS is usually assessed through Horizontal Dilution of Precision (HDOP.) The smaller the HDOP value, the better the positioning accuracy. Examples of SPS are GPS (Global Positioning System), Galileo, GLONASS, or Compass.
[0025] In one implementation, the elapsed time to obtain the fix (which is called time to fix or TTF) is used as an indicator of the quality of an estimated location. Specifically, in open environments and areas with good visibility to SPS satellites, fix comes quickly. On the other hand, in challenging environments for SPS devices, e.g., in a location with a limited view of the sky, fix might take some time to arrive. The hybrid position system can take advantage of this difference in TTF and assign a quality factor to SPS location. In addition, elapsed time after fix (TAF) can also be used as an indicator of the quality of an SPS estimated location. Time after fix (TAF) refers to the duration of time that a fix has been continuously provided without a gap in time. In general, in open environments and areas with good visibility to SPS satellites, an SPS device can maintain its fix. However, in challenging environments for SPS devices, the device might not be able to maintain the fix. This results in small TAF values and indicates that device is in challenging environment for SPS.
[0026] Furthermore, implementations of the invention combine the above metrics and use the result as an indicator of the quality of an SPS estimated location. The combination of TTF and TAF can be considered as another metric. The proposed metric looks for "gaps" in time for consecutive fixes. So if SPS fixes are obtained and lost frequently, system decides that the SPS device is in challenging environment for SPS. For example, if SPS fix is lost for 5 seconds and a fix is provided after five seconds,then TTFfor the new fix is 5s. If we get subsequent fixes for the next 120s, then TAF is 120s. The combination of TTF and TAF, 5s to get the fix and continuous fixes for 120s, would indicated that there is no gap in acquiring SPS fixes and the quality of SPS location is likely to be very good.
[0027] Secondary measures are also employed to estimate the quality of an SPS location estimate, as follows. The hybrid positioning system can use number of satellites used to calculate the SPS location as an indicator of type of environment. In open environments, the number of satellites used in a fix is generally large. On the other hand, in challenging environments for SPS, fixes are obtained with very few satellites, and fixes are maintained with few satellites. Also, the velocity of the device as determined by SPS can be used as a secondary measure of quality. In general, when the SPS velocity is relatively large, the SPS receiver is considered to be located in an open sky environment and its location is considered to be very accurate. For example, having SPS locations with reported velocity of 60mph would indicate that the device is in driving mode and hence likely to be outdoors and not indoors. This would indicate that the quality of SPS-provided location is good. Finally, the number of satellites currently in view can be used as an indicator of the type of environment. In open sky environments, generally, an SPS can receive signals from different satellites, and the number of satellites in view is large. On the other hand, in challenging environments for SPS, the number of satellites in view is low. Note that number of satellites in view refers to number of satellites from which the SPS receiver receives signal. The velocity in this discussion can come from SPS or other sources of location such as Wi-Fi positioning system. It can also come from other sensors on the device or working with the device. For example, the velocity can come from speedometer of a car which is connected to the device. Same discussion applies to bearing.
[0028] There also exist another measure to estimate the quality of the provided SPS location. The hybrid positioning system can use the variations in positions provided by SPS in specified time interval to measure the quality of SPS location. For example, variations measures such as variance, standard deviation, range, interquartile range, etc. might be used to gauge the variation of SPS position for 30 seconds of reporting location. In addition, the hybrid positioning system can use variations of other parameters related to SPS position in order to assess the quality of SPS reported location. The changes should follow a logical order of changes for a device. For example, the hybrid positioning system can use variations in velocity, bearing, and number of satellites used to derive the SPS location which all are reported by SPS. In such cases, huge jumps and variations in velocity or bearing of the device would indicate that SPS-provided locations might be of lower quality and/or the environment has changed.
[0029] The hybrid positioning system can also use the variation of combination of all the above parameters in order to assess the quality of the SPS location. In open and non- challenging environments to SPS, usually SPS provided location moves slowly from one point to the other point. In mobile devices that are within such environments, these changes can also be correlated with velocity of the vehicle and the integrity of the provided solution can be checked. The displacements in subsequent locations are according to the signals received from satellites and they follow the physical rules governing the device. For example, for a device moving with 10 m/s velocity, the location of the device from one point in time to a second after that time should only change 10 m. Changes much larger than 10 m would indicate that either the location or the velocity reported by SPS and other positioning systems were not correct and should raise a flag for the hybrid positioning system. For such quality checks, the hybrid positioning system, based on realistic values for velocity and bearing and previous SPS location, can reject a new reported SPS location, if the new location is much further than anticipated location. This can provide integrity on the reported location and avoid large jumps in location which are not feasible.
[0030] For another example, in open environments, the SPS location rarely has huge jumps in velocity and bearing as they should continuously change. Also, the number of satellites used to derive SPS location does not exhibit large jumps. This results in small variations in velocity, bearing, and number of satellites. On the other hand, in challenging environments, we frequently observe jumps in number of satellites reported by SPS. Velocity and bearing also show large variations. These changes are also not in line with change of velocity of the device. Therefore, the variations in the reported positions by SPS are significantly higher compared to open sky environments. Another specific variation can be defined as the jumps in reported location. This "jumpiness" behavior is usually not observed in open sky and non-challenging environment to SPS. On the other hand, in challenging environment for SPS, the location might frequently and unusually jump from a place to another place.
[0031] The next source of location examined here is a WiFi positioning system (WPS). WiFi positioning generally relies on received signals from different WiFi beacon devices. After receiving the signals from a wireless beacon or WiFi access point (AP) device, it might calculate the received power for all visible devices. WiFi Positioning then compares this information against a database of known AP devices and decides on the location of the user. WiFi Positioning is generally less accurate than SPS, but it has been shown that in challenging environments for SPS, WiFi Positioning can be more accurate. Such challenging environments might include urban canyons (a canyon-like effect created by surrounding buildings) and indoor environments. This disclosure discusses the possibility of detecting such cases and the type of environment. Based on such a conclusion, the hybrid positioning system selects the best possible location when both SPS and WiFi positioning are available.
[0032] In one implementation, the number of observed wireless beacons (i.e. wireless access points) can be used as an indicator of type of environment. In general, a large number of wireless devices can indicate a challenging environment for SPS, such as indoors or in a dense urban environment. If an environment is challenging for SPS, it might take longer to acquire a fix, and the accuracy of the fix might be lower. This might indicate that although both WiFi Positioning and SPS locations are available, the WiFi Positioning location might be more accurate. For example, in dense urban environments, the number of observed wireless devices typically follows a distribution where its mean is much larger than distribution of number of APs in open sky environments. This observation could indicate that the device is located in a dense urban environment, and its SPS location might not be as accurate as a WPS location, or SPS takes longer than normal to acquire a fix.
[0033] In addition, the quality of the location estimate returned from a WPS can be used as an indicator of the quality of WiFi Positioning location relative to other individual systems. The relative quality of reported locations from a WPS and an SPS enables the hybrid system to make a better decision in reporting the final location. For example, a very good location obtained from WiFi Positioning could be more accurate than a location obtained from SPS with few satellites and poor quality of location.
[0034] Some implementations can use the maximum observed power from observed wireless devices as an indicator of the type of the environment that the device is working and relate it to the relative quality of SPS and the quality of WiFi Positioning location. Generally, when a wireless device is observed with high power, it could indicate that the receiver is located in indoor environments. Hence, it could be difficult to obtain a high quality SPS location, which translates to higher time to fix and lower accuracy. This could indicate that any SPS provided location does not represent the true location and suffers from large inaccuracies in the provided location.
[0035] Further still, the distance between an SPS-provided location and a WiFi Positioning- provided location can be used as a metric to select between two reported locations. Generally, when the two locations are very far from one another, it is assumed that the SPS location is more accurate due to the nature of SPS. Hence, the hybrid positioning system should report the SPS location as its final location.
[0036] In further embodiments of the invention, an aggregate of different parameters, namely, number of satellites used in a fix, number of parameters in view, horizontal dilution of precision "HDOP," quality value of positioning in WiFi Positioning, inferred type of the environment the device is working in, number of WLAN devices used in WiFi Positioning, association information to an WLAN device, etc. are used to select the most accurate source of location. The aggregate parameters can indicate the type of environment in which the receiver resides. Thus, the system can use the aggregate information to select the best source among several location estimates. [0037] Also disclosed herein are techniques to use the aforementioned information to reduce the power consumption of a mobile device, and, thereby, increase battery life. In certain implementations, several parameters, namely, the number of WLAN devices used in WiFi Positioning and the maximum power observed from WLAN devices, are used to infer that the mobile deice is in a challenging environment for SPS. Thus, an SPS present in the mobile device is instructed to remain off or the powering-on of the SPS is delayed. Furthermore, the SPS can be powered-down if it does not acquire a fix within a designated period of time.
[0038] Such a technique can be employed when the mobile device starts a search for location. In traditional methods, the mobile device turns all devices on to find a location and presents the location result according to the waterfall switching algorithm. The techniques disclosed herein propose to use the above parameters to delay turning-on the SPS hardware, or avoid powering-on the SPS all together in certain situations, in order to reduce power consumption by the mobile device. Moreover, if powered on, the SPS hardware would be turned off if they do not acquire a fix within a predetermined period of time.
[0039] Similarly, other device and network information can be used to power-up or power- down portions of hardware or separate devices. Implementations of the invention propose to use association information between a WLAN AP and a mobile device, or any communication between a WiFi enabled device and a WLAN AP, as an indication of a high likelihood that the mobile device is indoor and/or is stationary. Such a determination can be used to delay powering-on SPS hardware in situations where it could not be completely confirmed that the device is indoors and/or is stationary. In the alternative, the SPS hardware can be left off or turned off if no location is acquired.
[0040] Further still, the techniques disclosed herein can be used to power-off SPS hardware within a mobile device when indications are detected that the mobile device is indoors or in a challenging environment for SPS. Similarly, the determination that the mobile device is indoors can be combined with the detection that the mobile device is not moving (or moving very slowly) to result in powering-off the SPS hardware. Therefore, when WPS hardware in the mobile device detects a low velocity, or that the user is stationary, the mobile device can power-off the SPS hardware to reduce power consumption. On the other hand, when the WPS hardware detects a moderate or higher velocity, the SPS hardware can be kept on.
[0041] The techniques disclosed herein also enable different methods to reduce the power consumption of mobile devices by dynamically changing the scan rate of the WiFi positioning system. In certain operating scenarios, increased scan rates do not improve the accuracy of position estimates of the system and only consume more power. Thus, some implementations determine if a scanning strategy is not optimized and adjust the scanning rate of the positioning engine to optimize the power consumption. In addition, some embodiments optimize the tradeoff between positioning accuracy and power. Parameters such as association to a WLAN device, velocity of the mobile unit estimated from different sources of location, number of WLAN devices used in WiFi Positioning, maximum power observed from any WLAN device in range, and number of satellites in view can be used to change the scanning rate of the positioning algorithm.
[0042] Other parameters can also be used to optimize the scanning rate. Scanning rate is defined as the rate of scanning the surrounding environment and searching for related signals for each positioning system. Scanning rate is applicable to Wi-Fi Positioning Systems and CPS. SPS typical continuously search for signals from satellites and updates location estimate every second. However, Wi-Fi Positioning Systems can have different scanning rates, therefore the rate of turning on the wireless device and scanning the environment for near by wireless APs can be different from SPS. The scanning rate of the Wi-Fi Positioning System or CPS can be adjusted dynamically when the positioning algorithm switches from initial location state (one- shot location - for applications without a need to track the device) to tracking state (in which location is updated periodically). For example, in such scenarios, the scanning rate for initial location state is lowered for power saving, while in tracking mode, because the user is concerned about receiving the best possible location, the scanning rate is increased to improve the accuracy. In another implementation, the time during which a location request is active is used to optimize the scanning rate. For example, if a particular application calls for a location request at a known frequency (e.g., every 10 seconds), then the scanning rate of the positioning algorithm can be adjusted to scan and/or power-on particular location system only when a location estimate must be provided.
[0043] In certain implementations, the techniques for reducing power consumption to increase battery life are disabled when the mobile device detects that it is connected to an external power source.
[0044] According to alternative embodiments, Fig. 3 illustrates the process of collecting relevant parameters of each location system (SPS, WPS, and CPS), using a reference database that may perform the initial position determination, and sending different parameters and the initial positions returned from the database to an algorithm implemented in a mobile device.
[0045] Fig. 4 illustrates a flow chart of a method for position estimation of a mobile device according to aspects of the present disclosure. Signals from at least two positioning systems are analyzed in step 410. In the example illustrated in Fig. 4, signals from a satellite positioning system ("SPS"), a Wi-Fi positioning system, and a cell positioning system ("CPS") are analyzed. The method determines a corresponding initial position estimate for the SPS (420), for the Wi-Fi positioning system (430), and/or for the CPS (440), based on the analyzed signals. The method in step 450 selects an initial position estimate as the final position estimate 460.
[0046] Fig. 5 illustrates a method for determining the type of environment using SPS parameters. When the device is in an open sky environment, there are no gaps between SPS fixes. For example, as seen at the top part of the figure, the TTF is between t=0 and t=5, and then the TAF is between t=5 and t=120. At the bottom part of the figure, there is an example of a challenging environment where there are a lot of instances where there is a fix and shortly after the fix is lost.
Example 1
[0047] The following discussion is one example of a method for switching between different sources of locations (individual positioning systems). In this example, the hybrid positioning system is assumed to have access to both an SPS and a WPS. During certain periods of time, each source of location is capable of providing a location estimate. However, at times, due to blockage of signals, for example, one or both systems are unable to provide a location estimate.
[0048] In such an operating scenario, the hybrid positioning system assesses the quality of the location estimates from each source of location. If location estimates from the SPS and the WPS are both available, the hybrid positioning system evaluates the accuracy of the location estimate provided by the SPS. For example, this can include analyzing the SPS parameters described above. If the quality of the location estimate provided by the SPS is high, the hybrid positioning system reports the SPS location immediately and does not evaluate the quality of the location estimate of the WPS. Otherwise, if the quality of the location estimate from the SPS is low, the hybrid positioning system analyzes the parameters of the WPS and compares the quality determinations. If the WPS accuracy is above a given threshold while the accuracy of the SPS location estimate has fallen below a certain threshold, the hybrid positioning system reports the location provided by the WPS. In cases where the position estimates from both the SPS and the WPS, the hybrid positioning system reports the SPS provided location. Finally, if only one source of location is able to provide an estimated location, then the hybrid positioning system reports the location from the only available system.
Example 2 [0049] In another illustrative implementation, a neural network can be used to select between the sources of location. This approach can be generalized when more sources are available. In the training phase of this approach, the hybrid positioning system is trained with a comprehensive set of data. Each data set includes an SPS location estimate and its associated parameters, a WPS location estimate and its associated parameters, a CPS location estimate and its associated parameters, and the best final decision that could be made for that case. In the training phase, the best final decision can be based on the known locations of the device when the training data set is assembled. The parameters associated with SPS and WPS sources of location are those described above. Parameters associated with CPS as a source of location include number of towers used for positioning, the relative power of the signals from the towers, the statistics of the signal power (e.g., variability, type of noise, etc.), and an error estimation associated with the towers, if available. After training the neural network with this dataset until it converges, the neural network determines a set of coefficients to be
arithmetically added or multiplied to the inputs of the neural network. These coefficients can then be used in a receiver program to select between all possible options.
[0050] Another technique for deciding which source(s) of location to use in a particular situation includes considering the history of previous location estimates. For example, assuming that both WPS and SPS estimates are available at the present moment and both have been available for a certain period of time, the hybrid positioning system can elect to use the SPS locations estimate as the present location. This is so because long-acquired SPS location estimates are believed to have more accurate locations than recent obtained location estimates. In other words, the time after obtaining a first location estimate in a current run of a hybrid positioning system can directly affect the decision as to which source of location is the most reliable and/or accurate. If a receiver is able to track SPS location estimates for more than several minutes, the location accuracy of that source is deemed to increase as time passes.
[0051] As discussed in more detail above, there are several implementations of the techniques disclosed herein for determining the most reliable and/or most accurate source of location in a particular situation. In some embodiments of the invention, the hybrid positioning system can use different algorithms to select between different sources of location depending on how long the hybrid positioning system has been operational after initialization. For example, upon initialization and for a predetermined time thereafter, the system can employ the switching technique set forth above in Example 1 , and at operational times greater than the predetermined time employ the switching technique set forth above in Example 2. [0052] The techniques and systems disclosed herein may be implemented as a computer program product for use with a computer system or computerized electronic device. Such implementations may include a series of computer instructions, or logic, fixed either on a tangible medium, such as a computer readable medium (e.g., a diskette, CD-ROM, ROM, flash memory or other memory or fixed disk) or transmittable to a computer system or a device, via a modem or other interface device, such as a communications adapter connected to a network over a medium.
[0053] The medium may be either a tangible medium (e.g., optical or analog
communications lines) or a medium implemented with wireless techniques (e.g., Wi-Fi, cellular, microwave, infrared or other transmission techniques). The series of computer instructions embodies at least part of the functionality described herein with respect to the system. Those skilled in the art should appreciate that such computer instructions can be written in a number of programming languages for use with many computer architectures or operating systems and under different platforms.
[0054] Furthermore, such instructions may be stored in any tangible memory device, such as semiconductor, magnetic, optical or other memory devices, and may be transmitted using any communications technology, such as optical, infrared, microwave, or other transmission technologies.
[0055] It is expected that such a computer program product may be distributed as a removable medium with accompanying printed or electronic documentation (e.g., shrink wrapped software), preloaded with a computer system (e.g., on system ROM or fixed disk), or distributed from a server or electronic bulletin board over the network (e.g., the Internet or World Wide Web). Of course, some embodiments of the invention may be implemented as a combination of both software (e.g., a computer program product) and hardware. Still other embodiments of the invention are implemented as entirely hardware, or entirely software (e.g., a computer program product).
[0056] Moreover, the techniques and systems disclosed herein can be used with a variety of mobile devices. For example, mobile telephones, smart phones, personal digital assistants, satellite positioning units (e.g., GPS devices), and/or mobile computing devices capable of receiving the signals discussed herein can be used in implementations of the invention. The location estimate, expected error of the position estimate, and/or the probability values can be displayed on the mobile device and/or transmitted to other devices and/or computer systems. Further, it will be appreciated that the scope of the present invention is not limited to the above - described embodiments, but rather is defined by the appended claims; and that these claims will encompass modifications of and improvements to what has been described.
[0057] What is claimed is:

Claims

1. A method for determining a position of a device using signals from multiple positioning systems, the method comprising:
analyzing signals from at least two of a satellite positioning system ("SPS"), a Wi-Fi positioning system, and a cell positioning system ("CPS");
determining for each of the at least two of the SPS, the Wi-Fi positioning system, and the CPS, a corresponding initial position estimate of the device and at least one corresponding parameter; and
selecting one of the corresponding initial position estimates as a final position estimate of the device based on at least one of a history of previously reported positions, the at least one corresponding SPS parameter, the at least one corresponding Wi-Fi positioning system parameter, and the at least one corresponding CPS parameter.
2. The method according to claim 1, wherein each initial position estimate is determined solely from the signals of the corresponding positioning system.
3. A method for determining a position of a device using signals from multiple positioning systems, the method comprising:
analyzing signals from at least two of a satellite positioning system ("SPS"), a Wi-Fi positioning system, and a cell positioning system ("CPS");
determining for each of the at least two of the SPS, the Wi-Fi positioning system, and the CPS, a corresponding initial position estimate of the device and corresponding parameters; selecting one of the corresponding initial position estimates as a final position estimate of the device based on at least one of a history of previously reported positions, the at least one corresponding SPS parameter, the at least one corresponding Wi-Fi positioning system parameter, and the at least one corresponding CPS parameter; and
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on the at least one of the history of the previously reported positions, the at least one corresponding SPS parameter, the at least one corresponding Wi-Fi positioning system parameter, and the at least one corresponding CPS parameter.
4. The method according to claim 3, wherein the SPS initial position is cached for a period of time.
5. A method for determining a position of a device using signals from multiple positioning systems, the method comprising:
analyzing signals from at least two of a satellite positioning system ("SPS"), a Wi-Fi positioning system, and a cell positioning system ("CPS");
determining for each of the at least two of the SPS, the Wi-Fi positioning system, and the CPS, a corresponding initial position estimate of the device and corresponding parameters; assessing for each of the corresponding initial position estimates a quality of the initial position estimate; and
selecting one of the corresponding initial position estimates as a final position estimate of the device based on the assessed qualities of the initial position estimates.
6. The method according to claim 5, wherein an elapsed time to obtain a fix (TTF) is used as an indicator of the quality of the initial position estimate of the SPS.
7. The method according to claim 6, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;
wherein the indicator of the type of environment is based on the TTF.
8. The method according to claim 5, wherein an elapsed time after a fix (TAF) is used as an indicator of the quality of the initial position estimate of the SPS.
9. The method according to claim 8, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;
wherein the indicator of the type of environment is based on the TAF.
10. The method according to claim 5, wherein a combination of a TTF and a TAF is used as an indicator of the quality of the initial position estimate of the SPS.
11. The method according to claim 10, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;
wherein the indicator of the type of environment is based on the combination of a TTF and a TAF.
12. The method according to claim 5, wherein a number of satellites in fix or in view is used as an indicator of the quality of the initial position estimate of the SPS.
13. The method according to claim 12, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment; wherein the indicator of the type of environment is based on the number of satellites in fix or in view.
14. The method according to claim 5, wherein a velocity of the device is used as an indicator of the quality of the initial position estimate of the SPS.
15. The method according to claim 14, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment; wherein the indicator of the type of environment is based on the velocity of the device.
16. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on a combination of at least two of a TTF, a TAF, a number of satellites in fix or in view, and a velocity of the device.
17. The method according to claim 16, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;
wherein the indicator of the type of environment is based on the combination of at least two of the TTF, the TAF, the number of satellites in fix or in view, and the velocity of the device.
18. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on variations in position estimates provided by the SPS.
19. The method according to claim 18, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment; wherein the indicator of the type of environment is based on the variations in position estimates provided by the SPS.
20. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on variations in velocity of the device.
21. The method according to claim 20, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment; wherein the indicator of the type of environment is based on the variations in velocity of the device.
22. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on variations in bearing.
23. The method according to claim 22, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment; wherein the indicator of the type of environment is based on the variations in bearing.
24. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on jumpiness of reported positions by the SPS.
25. The method according to claim 24, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment; wherein the indicator of the type of environment is based on the jumpiness of reported positions by the SPS.
26. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the Wi-Fi positioning system is based on a number of Wi-Fi access points in range of the device.
27. The method according to claim 26, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment; wherein the indicator of the type of environment is based on the number of Wi-Fi access points in range of the device.
28. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the Wi-Fi positioning system is based on a maximum observed power from Wi-Fi access points in range of the device.
29. The method according to claim 28, further comprising
switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;
wherein the indicator of the type of environment is based on the maximum observed power from Wi-Fi access points in range of the device.
30. The method according to claim 1, wherein selecting one of the corresponding initial position estimates of the device as a final position estimate of the device is according to the distance between the SPS-provided initial position estimate and the Wi-Fi positioning system initial position estimate.
31. The method according to claim 1 , wherein selecting one of the corresponding initial position estimates of the device as a final position estimate of the device is according to at least one of a number of satellites used in a fix, a horizontal dilution of precision, a number of Wi-Fi access points used in Wi-Fi positioning, association information to a Wi-Fi access point, and history of previous location estimates.
32. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on SPS parameters including at least one of a TTF, a TAF, a number of satellites in fix or in view, a velocity of the vehicle, a HDOP, variations of the TTF, variations of the TAF, variations of the number of satellites in fix or in view, variations of the velocity of the vehicle, and variations of the HDOP.
33. The method according to claim 32, further comprising
turning on or off logic in the device that determines initial position estimates based on an indicator of a type of environment;
changing the scanning rate of the Wi-Fi positioning system and/or the CPS based on an indicator of a type of environment;
wherein the indicator of the type of environment is based on the SPS parameters.
34. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the Wi-Fi positioning system is based on Wi-Fi parameters including at least one of a number of access points in range of the device, a maximum power, statistics of power, quality of Wi-Fi positioning systems, variations of the number of access points in range of the device, variations of the maximum power, variations of the statistics of power, variations of the quality of the initial position estimate of the Wi-Fi positioning systems.
35. The method according to claim 34, further comprising
turning on or off logic in the device that determines initial position estimates based on an indicator of a type of environment;
changing the scanning rate of the Wi-Fi positioning system and/or the CPS based on an indicator of a type of environment;
wherein the indicator of the type of environment is based on the Wi-Fi positioning system parameters.
36. The method according to claim 1, wherein a scanning rate of each of the at least two of a SPS, a Wi-Fi positioning system, and a CPS is individually optimized according to at least one of an association information to a Wi-Fi access point, a velocity of the device, a number of Wi-Fi access points used in Wi-Fi positioning, and a number of satellites used in view
37. The method according to claim 1, further comprising changing the scanning rate for the Wi-Fi positioning system or the CPS if the device is in one-shot or tracking mode.
38. The method according to claim 1, further comprising turning on or off the device based on the device being in one-shot or tracking mode.
39. The method according to claim 1, further comprising changing the scanning rate for the Wi-Fi positioning system or the CPS if the device is connected to an external power supply
40. The method according to claim 1, further comprising:
evaluating the quality of the corresponding initial position estimate of a first positioning system of the at least two of a SPS, a Wi-Fi positioning system, and a CPS; and
selecting the corresponding initial position estimate of the first positioning system as the final position estimate of the device without evaluating the quality of the initial position estimate of a second positioning system of the at least two of a SPS), a Wi-Fi positioning system, and a CPS.
41. A method for determining a position of a device using signals from multiple positioning systems, the method comprising:
analyzing signals from at least two of a satellite positioning system ("SPS"), a Wi-Fi positioning system, and a cell positioning system ("CPS");
determining for each of the at least two of a SPS, Wi-Fi positioning system, and CPS, a corresponding initial position estimate of the device based on the analyzed signals;
combining the corresponding initial position estimates to determine a combined initial position estimate; and
selecting either one of the corresponding initial position estimates of the device or the combined initial position estimate as a final position estimate of the device.
42. A computer-readable storage device containing a set of instructions that causes a mobile device to:
analyze signals from at least two of a satellite positioning system ("SPS"), a Wi-Fi positioning system, and a cell positioning system ("CPS");
determine for each of the at least two of a SPS, Wi-Fi positioning system, and CPS, a corresponding initial position estimate of the device based on the analyzed signals; and select one of the corresponding initial position estimates of the device as a final position estimate of the device.
PCT/US2011/059139 2010-11-03 2011-11-03 Method of system for increasing the reliability and accuracy of location estimation in a hybrid positioning system WO2012061595A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2013537820A JP2014501912A (en) 2010-11-03 2011-11-03 Method and system for increasing the reliability and accuracy of position estimation in a hybrid positioning system
EP11838809.9A EP2635915B1 (en) 2010-11-03 2011-11-03 Method of system for increasing the reliability and accuracy of location estimation in a hybrid positioning system
KR1020137014037A KR101972606B1 (en) 2010-11-03 2011-11-03 Method of system for increasing the reliability and accuracy of location estimation in a hybrid positioning system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US40964310P 2010-11-03 2010-11-03
US61/409,643 2010-11-03

Publications (1)

Publication Number Publication Date
WO2012061595A1 true WO2012061595A1 (en) 2012-05-10

Family

ID=46019124

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2011/059139 WO2012061595A1 (en) 2010-11-03 2011-11-03 Method of system for increasing the reliability and accuracy of location estimation in a hybrid positioning system

Country Status (5)

Country Link
US (1) US8890746B2 (en)
EP (1) EP2635915B1 (en)
JP (1) JP2014501912A (en)
KR (1) KR101972606B1 (en)
WO (1) WO2012061595A1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8462745B2 (en) 2008-06-16 2013-06-11 Skyhook Wireless, Inc. Methods and systems for determining location using a cellular and WLAN positioning system by selecting the best WLAN PS solution
US8564481B2 (en) 2009-07-16 2013-10-22 Skyhook Wireless, Inc. Systems and methods for using a satellite positioning system to detect moved WLAN access points
US8638256B2 (en) 2009-09-29 2014-01-28 Skyhook Wireless, Inc. Accuracy and performance of a hybrid positioning system
US8890746B2 (en) 2010-11-03 2014-11-18 Skyhook Wireless, Inc. Method of and system for increasing the reliability and accuracy of location estimation in a hybrid positioning system
US9135802B2 (en) 2012-05-24 2015-09-15 Google Inc. Hardware attitude detection implementation of mobile devices with MEMS motion sensors
US9329701B2 (en) 2012-11-21 2016-05-03 Google Technology Holdings LLC Low power management of multiple sensor chip architecture
JP2016522391A (en) * 2013-03-15 2016-07-28 クアルコム,インコーポレイテッド Energy saving device for geofence applications
US9697465B2 (en) 2014-04-30 2017-07-04 Google Technology Holdings LLC Drawing an inference of a usage context of a computing device using multiple sensors

Families Citing this family (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8369264B2 (en) 2005-10-28 2013-02-05 Skyhook Wireless, Inc. Method and system for selecting and providing a relevant subset of Wi-Fi location information to a mobile client device so the client device may estimate its position with efficient utilization of resources
EP1851979B1 (en) 2005-02-22 2018-06-13 Skyhook Wireless, Inc. Method of continuous data optimization in a positioning system
US7551579B2 (en) * 2006-05-08 2009-06-23 Skyhook Wireless, Inc. Calculation of quality of wlan access point characterization for use in a wlan positioning system
US7835754B2 (en) 2006-05-08 2010-11-16 Skyhook Wireless, Inc. Estimation of speed and direction of travel in a WLAN positioning system
US7515578B2 (en) 2006-05-08 2009-04-07 Skyhook Wireless, Inc. Estimation of position using WLAN access point radio propagation characteristics in a WLAN positioning system
JP2009543074A (en) 2006-07-07 2009-12-03 スカイフック ワイヤレス,インク. System and method for collecting information from a WLAN-enabled access point to estimate the location of a WLAN positioning device
US8619643B2 (en) * 2010-03-24 2013-12-31 Skyhook Wireless, Inc. System and method for estimating the probability of movement of access points in a WLAN-based positioning system
US8700053B2 (en) 2010-06-11 2014-04-15 Skyhook Wireless, Inc. Systems for and methods of determining likelihood of relocation of reference points in a positioning system
US8606294B2 (en) 2010-10-05 2013-12-10 Skyhook Wireless, Inc. Method of and system for estimating temporal demographics of mobile users
US20120331561A1 (en) 2011-06-22 2012-12-27 Broadstone Andrew J Method of and Systems for Privacy Preserving Mobile Demographic Measurement of Individuals, Groups and Locations Over Time and Space
US8682345B2 (en) 2011-09-28 2014-03-25 Qualcomm Incorporated Utilizing relationships between places of relevance
US9467494B1 (en) 2011-12-30 2016-10-11 Rupaka Mahalingaiah Method and apparatus for enabling mobile cluster computing
US9116233B2 (en) 2012-07-10 2015-08-25 Broadcom Corporation Power mode control for sensors
US10168161B2 (en) 2012-10-22 2019-01-01 Qualcomm Incorporated Changing a position determination scheme used by a user equipment during a transition between indoor and outdoor spaces relative to an enclosed environment
US9408136B2 (en) 2013-03-12 2016-08-02 Qualcomm Incorporated Method and apparatus for performing scan operations
US20140278838A1 (en) * 2013-03-14 2014-09-18 Uber Technologies, Inc. Determining an amount for a toll based on location data points provided by a computing device
US9191897B2 (en) 2013-03-22 2015-11-17 Qualcomm Incorporated Mobile device power management while providing location services
EP2806285B1 (en) * 2013-05-24 2018-12-19 Nxp B.V. A vehicle positioning system
JP6351235B2 (en) * 2013-11-06 2018-07-04 アルパイン株式会社 Navigation system, computer program, and current position calculation method
KR102207584B1 (en) 2014-04-03 2021-01-26 한국전자통신연구원 Method and apparatus of intergrated positioning
US9715017B2 (en) * 2015-03-06 2017-07-25 Iposi, Inc. Using DME for terrestrial time transfer
US20160313450A1 (en) * 2015-04-27 2016-10-27 Autoliv Asp, Inc. Automotive gnss real time kinematic dead reckoning receiver
KR102034082B1 (en) 2015-05-13 2019-10-18 한국전자통신연구원 Positioning environment analysis apparatus, positioning performance projection method and system of terminal using the same
US20170013590A1 (en) * 2015-07-09 2017-01-12 Qualcomm Incorporated Determining wireless scanning rate based on pedestrian dead reckoning reliability
US10205731B2 (en) * 2015-09-25 2019-02-12 Microsoft Technology Licensing, Llc Contextually-aware location sharing services
US9936348B2 (en) 2016-05-02 2018-04-03 Skyhook Wireless, Inc. Techniques for establishing and using associations between location profiles and beacon profiles
US9635510B1 (en) 2016-06-24 2017-04-25 Athentek Innovations, Inc. Database for Wi-Fi position estimation
US10650621B1 (en) 2016-09-13 2020-05-12 Iocurrents, Inc. Interfacing with a vehicular controller area network
US10459085B1 (en) * 2016-11-04 2019-10-29 Rockwell Collins, Inc. System and method for validating GPS altitude for low visibility approaches
JP6416849B2 (en) * 2016-11-08 2018-10-31 ソフトバンク株式会社 Information processing apparatus, program, and information processing method
EP3750353A1 (en) 2018-02-05 2020-12-16 Sony Corporation Selecting a positioning technique based on the accuracy
MY195505A (en) * 2018-12-31 2023-01-27 Mimos Berhad System And Method For Estimating Geospatial Position By Composing Positioning Scheme
US11917488B2 (en) 2019-09-13 2024-02-27 Troverlo, Inc. Passive asset tracking using observations of pseudo Wi-Fi access points
US11589187B2 (en) 2019-09-13 2023-02-21 Troverlo, Inc. Passive sensor tracking using observations of Wi-Fi access points
US11622234B2 (en) 2019-09-13 2023-04-04 Troverlo, Inc. Passive asset tracking using observations of Wi-Fi access points
CN111413719B (en) * 2020-03-21 2022-07-15 哈尔滨工程大学 Beidou real-time precise clock prediction method based on neural network
CN112261606B (en) * 2020-09-28 2021-09-07 南京邮电大学 Self-adaptive indoor fusion positioning method based on dynamic environment
JP7409330B2 (en) * 2021-01-28 2024-01-09 トヨタ自動車株式会社 Self-position estimation accuracy verification method, self-position estimation system
WO2023064812A1 (en) * 2021-10-13 2023-04-20 Apple Inc. Machine learning based positioning
EP4306984A1 (en) * 2022-07-13 2024-01-17 Rohde & Schwarz GmbH & Co. KG Method of geographic positioning of a receiver device, and receiver device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6975266B2 (en) * 2003-06-17 2005-12-13 Global Locate, Inc. Method and apparatus for locating position of a satellite signal receiver
US20060049982A1 (en) * 2004-09-03 2006-03-09 Telefonaktiebolaget L M Ericsson (Publ) Method of and system for reducing a time to fix in a location-enabled receiver
US7151939B2 (en) * 2003-02-18 2006-12-19 Qualcomm Incorporated Method, apparatus, and machine-readable medium for providing indication of location service availability and the quality of available location services
US20080291086A1 (en) 2007-05-25 2008-11-27 Broadcom Corporation Position determination using available positioning techniques
US20090192709A1 (en) 2008-01-25 2009-07-30 Garmin Ltd. Position source selection
US7660588B2 (en) * 2002-10-17 2010-02-09 Qualcomm Incorporated Method and apparatus for improving radio location accuracy with measurements
US20100039323A1 (en) * 2008-08-12 2010-02-18 Andrei Kosolobov Method and system for global position reference map (gprm) for agps

Family Cites Families (232)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881060A (en) 1973-06-04 1975-04-29 Bell Telephone Labor Inc Emergency reporting system
US4310726A (en) 1980-02-04 1982-01-12 Bell Telephone Laboratories, Incorporated Method of identifying a calling station at a call terminating facility
US4415771A (en) 1981-04-03 1983-11-15 Louis Martinez Public alert and advisory systems
JPH063431Y2 (en) 1984-03-14 1994-01-26 日本電気株式会社 Flat panel drive
GB2180425B (en) 1985-09-13 1989-11-22 Stc Plc Navigation system and method
JPS62284277A (en) 1986-06-02 1987-12-10 Japan Radio Co Ltd Hybrid navigation device by gps and loran c
US4757267A (en) 1987-06-17 1988-07-12 Applied Telematics, Inc. Telephone system for connecting a customer to a supplier of goods
US4876550A (en) 1987-10-08 1989-10-24 Allied-Signal Inc. Ridge regression signal processing for position-fix navigation systems
JPH02502128A (en) 1987-10-23 1990-07-12 ヒューズ・エアクラフト・カンパニー Improving the detection accuracy of vehicle position detection systems used for vehicles in flight
US4924491A (en) 1988-11-18 1990-05-08 American Telephone And Telegraph Company Arrangement for obtaining information about abandoned calls
JPH03235562A (en) 1990-02-13 1991-10-21 Fujitsu Ltd Calling area identification system
US5095505A (en) 1990-02-28 1992-03-10 Mci Communications Corp. Efficient flexible special service call processing
JP2751566B2 (en) 1990-05-28 1998-05-18 富士通株式会社 Representative telephone number service
US5389935A (en) 1990-06-13 1995-02-14 Thomson-Csf Automatic system for locating and identifying vehicles in distress
US5119504A (en) 1990-07-19 1992-06-02 Motorola, Inc. Position aided subscriber unit for a satellite cellular system
GB9016277D0 (en) 1990-07-25 1990-09-12 British Telecomm Location and handover in mobile radio systems
US5043736B1 (en) 1990-07-27 1994-09-06 Cae Link Corp Cellular position location system
US5161180A (en) 1990-10-19 1992-11-03 Chavous Robert O Call interceptor for emergency systems
CA2056203A1 (en) 1990-12-31 1992-07-01 Craig A. Reading Method and circuitry for routing a call from a calling station to a desired nearby destination station
US5136636A (en) 1991-02-07 1992-08-04 At&T Bell Laboratories Telephone connection to a nearby dealer
US5235630A (en) 1991-04-17 1993-08-10 Telident, Incorporated Emergency call station identification system and method
JP3058942B2 (en) 1991-06-27 2000-07-04 三菱電機株式会社 Navigation device
US5315636A (en) 1991-06-28 1994-05-24 Network Access Corporation Personal telecommunications system
AU661706B2 (en) 1991-07-01 1995-08-03 Lans Hakan A position indicating system
US5379337A (en) 1991-08-16 1995-01-03 U S West Advanced Technologies, Inc. Method and system for providing emergency call service
US5235633A (en) 1991-12-26 1993-08-10 Everett Dennison Cellular telephone system that uses position of a mobile unit to make call management decisions
US5334974A (en) 1992-02-06 1994-08-02 Simms James R Personal security system
CA2089123A1 (en) 1992-03-04 1993-09-05 Robert Edwin Penny, Jr. Position locating transceiver
JPH06148308A (en) 1992-11-05 1994-05-27 Toshiba Corp Traveling body position detector
US5420592A (en) 1993-04-05 1995-05-30 Radix Technologies, Inc. Separated GPS sensor and processing system for remote GPS sensing and centralized ground station processing for remote mobile position and velocity determinations
US5572216A (en) 1993-11-19 1996-11-05 Stanford Telecommunications, Inc. System for increasing the utility of satellite communication systems
US5936572A (en) 1994-02-04 1999-08-10 Trimble Navigation Limited Portable hybrid location determination system
US5510801A (en) 1994-03-01 1996-04-23 Stanford Telecommunications, Inc. Location determination system and method using television broadcast signals
GB2291300B (en) 1994-06-20 1997-12-17 Motorola Ltd Communications system
US5564121A (en) 1994-08-18 1996-10-08 Northern Telecom Limited Microcell layout having directional and omnidirectional antennas defining a rectilinear layout in a building
AU4684596A (en) 1994-12-23 1996-07-19 Stanford Telecommunications, Inc. Position enhanced communication system
US5612864A (en) 1995-06-20 1997-03-18 Caterpillar Inc. Apparatus and method for determining the position of a work implement
US5902351A (en) 1995-08-24 1999-05-11 The Penn State Research Foundation Apparatus and method for tracking a vehicle
US6208290B1 (en) 1996-03-08 2001-03-27 Snaptrack, Inc. GPS receiver utilizing a communication link
AUPN733395A0 (en) 1995-12-22 1996-01-25 University Of Technology, Sydney Location and tracking system
WO1997028455A1 (en) 1996-02-01 1997-08-07 Stanford Telecommunications, Inc. Radio navigation system using out-of-band pseudolites
JP3231787B2 (en) 1996-03-05 2001-11-26 松下電器産業株式会社 Location information detection system
EP0810449A1 (en) 1996-05-31 1997-12-03 Megapulse Incorporated Navigation system
US6185427B1 (en) 1996-09-06 2001-02-06 Snaptrack, Inc. Distributed satellite position system processing and application network
AU4338597A (en) 1996-09-09 1998-03-26 Dennis Jay Dupray Location of a mobile station using a plurality of commercial wireless infrastructures
WO1998010307A1 (en) 1996-09-09 1998-03-12 Dennis Jay Dupray Location of a mobile station
US5943606A (en) 1996-09-30 1999-08-24 Qualcomm Incorporated Determination of frequency offsets in communication systems
US5940825A (en) 1996-10-04 1999-08-17 International Business Machines Corporation Adaptive similarity searching in sequence databases
US5969674A (en) 1997-02-21 1999-10-19 Von Der Embse; Urban A. Method and system for determining a position of a target vehicle utilizing two-way ranging
US6006260A (en) 1997-06-03 1999-12-21 Keynote Systems, Inc. Method and apparatus for evalutating service to a user over the internet
US6262741B1 (en) 1998-03-17 2001-07-17 Prc Public Sector, Inc. Tiling of object-based geographic information system (GIS)
US6192314B1 (en) 1998-03-25 2001-02-20 Navigation Technologies Corp. Method and system for route calculation in a navigation application
US5999124A (en) 1998-04-22 1999-12-07 Snaptrack, Inc, Satellite positioning system augmentation with wireless communication signals
US6313786B1 (en) 1998-07-02 2001-11-06 Snaptrack, Inc. Method and apparatus for measurement processing of satellite positioning system (SPS) signals
JP2000029521A (en) 1998-07-08 2000-01-28 Fuji Heavy Ind Ltd Autonomous traveling method and autonomously traveling vehicle
US6321090B1 (en) 1998-11-06 2001-11-20 Samir S. Soliman Mobile communication system with position detection to facilitate hard handoff
US6192312B1 (en) 1999-03-25 2001-02-20 Navigation Technologies Corp. Position determining program and method
US6725158B1 (en) 1999-07-12 2004-04-20 Skybitz, Inc. System and method for fast acquisition reporting using communication satellite range measurement
FI19992236A (en) 1999-10-15 2001-04-16 Nokia Networks Oy Location determination in a telecommunications network
US6353398B1 (en) 1999-10-22 2002-03-05 Himanshu S. Amin System for dynamically pushing information to a user utilizing global positioning system
US6429808B1 (en) 1999-11-12 2002-08-06 Motorola, Inc. Method and apparatus for assisted GPS integrity maintenance
US6665658B1 (en) 2000-01-13 2003-12-16 International Business Machines Corporation System and method for automatically gathering dynamic content and resources on the world wide web by stimulating user interaction and managing session information
US6587692B1 (en) 2000-03-30 2003-07-01 Lucent Technologies Inc. Location determination using weighted ridge regression
US7038584B2 (en) 2000-03-31 2006-05-02 Ge Medical Systems Information Technologies, Inc. Object location monitoring within buildings
US7917390B2 (en) 2000-06-09 2011-03-29 Sony Corporation System and method for providing customized advertisements over a network
US7373425B2 (en) 2000-08-22 2008-05-13 Conexant Systems, Inc. High-speed MAC address search engine
US20020055956A1 (en) 2000-09-08 2002-05-09 Krasnoiarov Boris Andreyevich Method and system for assembling concurrently-generated content
US6420999B1 (en) 2000-10-26 2002-07-16 Qualcomm, Inc. Method and apparatus for determining an error estimate in a hybrid position determination system
US6799049B1 (en) 2000-12-19 2004-09-28 Bellsouth Intellectual Property Corporation System and method for tracking movement of a wireless device
FI111901B (en) 2000-12-29 2003-09-30 Ekahau Oy Estimation of position in wireless communication networks
JP3543769B2 (en) 2001-02-19 2004-07-21 株式会社日立製作所 Device for measuring the position of mobile terminals
US7187278B2 (en) 2001-03-06 2007-03-06 Peter Biffar Rule based proximity and time based tracking system
JP2002281540A (en) 2001-03-19 2002-09-27 Hitachi Ltd Mobile terminal equipment for measuring position
JP2005509136A (en) 2001-04-03 2005-04-07 エイ ティ アンド ティ ワイヤレス サービシズ インコーポレイテッド Mobile station location estimation method and apparatus
JP2002328157A (en) 2001-04-27 2002-11-15 Pioneer Electronic Corp Positioning error area setting device, positioning error area setting method, positioning error area setting processing program and navigation device
US6594483B2 (en) 2001-05-15 2003-07-15 Nokia Corporation System and method for location based web services
US6594576B2 (en) 2001-07-03 2003-07-15 At Road, Inc. Using location data to determine traffic information
JP3547412B2 (en) 2001-07-24 2004-07-28 株式会社日立製作所 Wireless terminal device and positioning system
WO2003021851A2 (en) 2001-09-05 2003-03-13 Newbury Networks, Inc. Position detection and location tracking in a wireless network
WO2003024131A1 (en) 2001-09-10 2003-03-20 Sirf Technology, Inc. System for utilizing cell information to locate a wireless device
US6888811B2 (en) 2001-09-24 2005-05-03 Motorola, Inc. Communication system for location sensitive information and method therefor
US6771211B2 (en) 2001-11-13 2004-08-03 Nokia Corporation Method, system and devices for positioning a receiver
US20030125045A1 (en) 2001-12-27 2003-07-03 Riley Wyatt Thomas Creating and using base station almanac information in a wireless communication system having a position location capability
JP2002310692A (en) * 2002-01-09 2002-10-23 Hitachi Ltd Mobile terminal device for performing position measurement
KR20030067341A (en) 2002-02-08 2003-08-14 주식회사 팬택앤큐리텔 Coherent type demodulation device of base transceiver station in interim standard-2000 system
US6795718B2 (en) 2002-02-15 2004-09-21 Youngbo Engineering, Inc. Headset communication device
US6754488B1 (en) 2002-03-01 2004-06-22 Networks Associates Technologies, Inc. System and method for detecting and locating access points in a wireless network
EP2375689A3 (en) 2002-03-01 2012-01-11 Enterasys Networks, Inc. Location discovery in a data network
US20030186679A1 (en) 2002-03-27 2003-10-02 International Business Machines Corporation Methods, apparatus and program product for monitoring network security
US20040203847A1 (en) 2002-03-28 2004-10-14 Knauerhase Robert C. Location-based task notification
JP4093792B2 (en) 2002-04-18 2008-06-04 富士通株式会社 Positioning system, program and position determining method for determining position of mobile radio station
US6664925B1 (en) 2002-05-02 2003-12-16 Microsoft Corporation Method and system for determining the location of a mobile computer
US20030225714A1 (en) 2002-05-16 2003-12-04 Catalasan Peter Paul Martizano Formulator
US7167715B2 (en) 2002-05-17 2007-01-23 Meshnetworks, Inc. System and method for determining relative positioning in AD-HOC networks
US7086089B2 (en) 2002-05-20 2006-08-01 Airdefense, Inc. Systems and methods for network security
US7277404B2 (en) 2002-05-20 2007-10-02 Airdefense, Inc. System and method for sensing wireless LAN activity
US7532895B2 (en) 2002-05-20 2009-05-12 Air Defense, Inc. Systems and methods for adaptive location tracking
US6956527B2 (en) 2002-06-24 2005-10-18 Intel Corporation Wireless network access point configuration
US8095657B2 (en) 2002-07-24 2012-01-10 Oracle America, Inc. First thread lock management for distributed data systems
AU2003256549A1 (en) 2002-07-31 2004-02-16 Interdigital Technology Corporation Handover between a cellular system and a wireless local area network
US7068999B2 (en) 2002-08-02 2006-06-27 Symbol Technologies, Inc. System and method for detection of a rogue wireless access point in a wireless communication network
US7590079B2 (en) 2002-10-25 2009-09-15 Motorola, Inc. Method of communication device initiated frame exchange
US7050787B2 (en) 2002-10-30 2006-05-23 Lockheed Martin Corporation Cooperative element location system
US7257411B2 (en) 2002-12-27 2007-08-14 Ntt Docomo, Inc. Selective fusion location estimation (SELFLOC) for wireless access technologies
US7130646B2 (en) 2003-02-14 2006-10-31 Atheros Communications, Inc. Positioning with wireless local area networks and WLAN-aided global positioning systems
US7242950B2 (en) 2003-02-18 2007-07-10 Sbc Properties, L.P. Location determination using historical data
US20050070263A1 (en) 2003-02-24 2005-03-31 Floyd Backes Wireless access point protocol logic
US7130642B2 (en) 2003-03-03 2006-10-31 Qualcomm Incorporated Method and apparatus for performing position determination in a wireless communication network with repeaters
US6978023B2 (en) 2003-03-25 2005-12-20 Sony Corporation Apparatus and method for location based wireless client authentication
US7853250B2 (en) 2003-04-03 2010-12-14 Network Security Technologies, Inc. Wireless intrusion detection system and method
US7522908B2 (en) 2003-04-21 2009-04-21 Airdefense, Inc. Systems and methods for wireless network site survey
JP2004361186A (en) 2003-06-03 2004-12-24 Sony Corp Positional information positioning device
US7440755B2 (en) 2003-06-17 2008-10-21 Telefonaktiebolaget L M Ericsson (Publ) System and method for locating a wireless local area network
US7313402B1 (en) 2003-06-24 2007-12-25 Verizon Corporate Services Group Inc. System and method for evaluating accuracy of an automatic location identification system
US8971913B2 (en) 2003-06-27 2015-03-03 Qualcomm Incorporated Method and apparatus for wireless network hybrid positioning
US8483717B2 (en) 2003-06-27 2013-07-09 Qualcomm Incorporated Local area network assisted positioning
BR122018004395B1 (en) 2003-06-27 2020-11-10 Qualcomm Incorporated method and equipment for hybrid wireless network positioning
US7250907B2 (en) 2003-06-30 2007-07-31 Microsoft Corporation System and methods for determining the location dynamics of a portable computing device
US7123928B2 (en) 2003-07-21 2006-10-17 Qualcomm Incorporated Method and apparatus for creating and using a base station almanac for position determination
CA2533145C (en) 2003-07-23 2013-04-09 Qualcomm Incorporated Selecting a navigation solution used in determining the position of a device in a wireless communication system
US6990428B1 (en) 2003-07-28 2006-01-24 Cisco Technology, Inc. Radiolocation using path loss data
US7343564B2 (en) 2003-08-11 2008-03-11 Core Mobility, Inc. Systems and methods for displaying location-based maps on communication devices
GB2405276B (en) 2003-08-21 2005-10-12 Motorola Inc Measuring distance using wireless communication
WO2005050849A2 (en) 2003-10-01 2005-06-02 Laird Mark D Wireless virtual campus escort system
US7412246B2 (en) 2003-10-06 2008-08-12 Symbol Technologies, Inc. Method and system for improved wlan location
US7069024B2 (en) 2003-10-31 2006-06-27 Symbol Technologies, Inc. System and method for determining location of rogue wireless access point
US20050105600A1 (en) 2003-11-14 2005-05-19 Okulus Networks Inc. System and method for location tracking using wireless networks
US7856209B1 (en) 2003-12-08 2010-12-21 Airtight Networks, Inc. Method and system for location estimation in wireless networks
US6894645B1 (en) 2003-12-11 2005-05-17 Nokia Corporation Position estimation
US8804532B2 (en) 2003-12-15 2014-08-12 Unwired Planet, Llc Method and arrangement for adapting to variations in an available bandwidth to a local network
US7171217B2 (en) 2004-01-22 2007-01-30 Mci, Llc Location finder
US7389114B2 (en) 2004-02-11 2008-06-17 Avaya Technology Corp. Estimating the location of inexpensive wireless terminals by using signal strength measurements
US7116988B2 (en) 2004-03-16 2006-10-03 Airespace, Inc. Location of wireless nodes using signal strength weighting metric
US7545894B2 (en) 2004-03-19 2009-06-09 Purdue Research Foundation Method and apparatus for detecting and processing global positioning system (GPS) signals
US7917153B2 (en) 2004-03-31 2011-03-29 France Telecom Method and apparatus for creating, directing, storing and automatically delivering a message to an intended recipient upon arrival of a specified mobile object at a designated location
US7308247B2 (en) 2004-04-05 2007-12-11 Demetrius Thompson Cellular telephone safety system
US6965576B1 (en) 2004-04-21 2005-11-15 Telcordia Technologies, Inc. Automatic configuration of WLAN for mobile users
US7433696B2 (en) 2004-05-18 2008-10-07 Cisco Systems, Inc. Wireless node location mechanism featuring definition of search region to optimize location computation
US7155239B2 (en) 2004-05-28 2006-12-26 Symbol Technologies, Inc. Method and system for radio map filtering via adaptive clustering
KR100797348B1 (en) 2004-06-15 2008-01-22 엘지전자 주식회사 Navigation system
US7319878B2 (en) 2004-06-18 2008-01-15 Qualcomm Incorporated Method and apparatus for determining location of a base station using a plurality of mobile stations in a wireless mobile network
US7209077B2 (en) 2004-06-29 2007-04-24 Andrew Corporation Global positioning system signal acquisition assistance
US7509131B2 (en) 2004-06-29 2009-03-24 Microsoft Corporation Proximity detection using wireless signal strengths
US8032156B2 (en) * 2004-09-07 2011-10-04 Qualcomm Incorporated Procedure to increase position location availabilty
US20060063560A1 (en) 2004-09-21 2006-03-23 Samsung Electronics Co., Ltd. Dual-mode phone using GPS power-saving assist for operating in cellular and WiFi networks
JP4400395B2 (en) 2004-09-27 2010-01-20 株式会社日立製作所 Position calculation method and program thereof
US8005483B2 (en) 2004-10-27 2011-08-23 Qwest Communications International Inc. Mobile caching and data relay vectoring systems and methods
ES2391566T3 (en) 2004-10-29 2012-11-27 Skyhook Wireless, Inc. Database and location beacon server, method to build a location beacon database, and location-based service that uses it
US8369264B2 (en) 2005-10-28 2013-02-05 Skyhook Wireless, Inc. Method and system for selecting and providing a relevant subset of Wi-Fi location information to a mobile client device so the client device may estimate its position with efficient utilization of resources
US7254405B2 (en) 2004-11-22 2007-08-07 Motorola, Inc. System and method for providing location information to applications
US7426197B2 (en) 2004-11-24 2008-09-16 Qualcomm Incorporated Method and apparatus for location determination of a wireless device within an environment
KR100689517B1 (en) 2004-12-13 2007-03-02 삼성전자주식회사 System of assisted gps using network time protocol server and method measuring location of mobile phone thereof
US7696923B2 (en) 2005-02-03 2010-04-13 Mexens Intellectual Property Holding Llc System and method for determining geographic location of wireless computing devices
US7397424B2 (en) 2005-02-03 2008-07-08 Mexens Intellectual Property Holding, Llc System and method for enabling continuous geographic location estimation for wireless computing devices
EP1851979B1 (en) 2005-02-22 2018-06-13 Skyhook Wireless, Inc. Method of continuous data optimization in a positioning system
US7502620B2 (en) 2005-03-04 2009-03-10 Shyhook Wireless, Inc. Encoding and compression of a location beacon database
US7174172B2 (en) 2005-02-25 2007-02-06 Symbol Technologies, Inc. System and method for asset location in wireless networks
US7479922B2 (en) 2005-03-31 2009-01-20 Deere & Company Method and system for determining the location of a vehicle
US20060221918A1 (en) 2005-04-01 2006-10-05 Hitachi, Ltd. System, method and computer program product for providing content to a remote device
US7257413B2 (en) 2005-08-24 2007-08-14 Qualcomm Incorporated Dynamic location almanac for wireless base stations
US7522099B2 (en) 2005-09-08 2009-04-21 Topcon Gps, Llc Position determination using carrier phase measurements of satellite signals
US7587081B2 (en) 2005-09-28 2009-09-08 Deere & Company Method for processing stereo vision data using image density
WO2007036737A1 (en) 2005-09-30 2007-04-05 British Telecommunications Public Limited Company Information based on location and activity of a user
US7471455B2 (en) 2005-10-28 2008-12-30 Cymer, Inc. Systems and methods for generating laser light shaped as a line beam
US20070100955A1 (en) 2005-10-29 2007-05-03 Bodner Oran J System and method for using known geographic locations of Internet users to present local content to web pages
RU2390791C2 (en) 2005-11-07 2010-05-27 Квэлкомм Инкорпорейтед Positioning for wlan and other wireless networks
US7701388B2 (en) 2005-11-15 2010-04-20 O2Micro International Ltd. Novas hybrid positioning technology using terrestrial digital broadcasting signal (DBS) and global positioning system (GPS) satellite signal
WO2007062192A2 (en) 2005-11-23 2007-05-31 Skyhook Wireless, Inc. Location toolbar for internet search and communication
US7664511B2 (en) 2005-12-12 2010-02-16 Nokia Corporation Mobile location method for WLAN-type systems
US7466986B2 (en) 2006-01-19 2008-12-16 International Business Machines Corporation On-device mapping of WIFI hotspots via direct connection of WIFI-enabled and GPS-enabled mobile devices
US7471954B2 (en) 2006-02-24 2008-12-30 Skyhook Wireless, Inc. Methods and systems for estimating a user position in a WLAN positioning system based on user assigned access point locations
US20070217374A1 (en) 2006-03-15 2007-09-20 Shay Waxman Techniques to collaborate wireless terminal position location information from multiple wireless networks
JP4768494B2 (en) 2006-03-31 2011-09-07 テルモ株式会社 Diagnostic imaging apparatus and processing method thereof
US8014788B2 (en) 2006-05-08 2011-09-06 Skyhook Wireless, Inc. Estimation of speed of travel using the dynamic signal strength variation of multiple WLAN access points
US7835754B2 (en) 2006-05-08 2010-11-16 Skyhook Wireless, Inc. Estimation of speed and direction of travel in a WLAN positioning system
US7551929B2 (en) 2006-05-08 2009-06-23 Skyhook Wireless, Inc. Estimation of speed and direction of travel in a WLAN positioning system using multiple position estimations
US7551579B2 (en) 2006-05-08 2009-06-23 Skyhook Wireless, Inc. Calculation of quality of wlan access point characterization for use in a wlan positioning system
US7515578B2 (en) 2006-05-08 2009-04-07 Skyhook Wireless, Inc. Estimation of position using WLAN access point radio propagation characteristics in a WLAN positioning system
US7656348B2 (en) 2006-05-19 2010-02-02 Qualcomm Incorporated System and/or method for determining sufficiency of pseudorange measurements
JP4989112B2 (en) 2006-05-31 2012-08-01 株式会社エヌ・ティ・ティ・ドコモ Server device, mobile terminal, and positioning method selection method
US8571580B2 (en) 2006-06-01 2013-10-29 Loopt Llc. Displaying the location of individuals on an interactive map display on a mobile communication device
US7925278B2 (en) 2006-06-27 2011-04-12 Motorola Mobility, Inc. Method and system for locating a wireless device in a wireless communication network
US8239286B2 (en) 2006-06-29 2012-08-07 Microsoft Corporation Medium and system for location-based E-commerce for mobile communication devices
JP2009543074A (en) 2006-07-07 2009-12-03 スカイフック ワイヤレス,インク. System and method for collecting information from a WLAN-enabled access point to estimate the location of a WLAN positioning device
KR101217939B1 (en) 2006-08-01 2013-01-02 퀄컴 인코포레이티드 System and/or method for providing information updates to a location server
CN101523862A (en) 2006-08-04 2009-09-02 探空气球无线公司 Systems and methods of automated retrieval of location information from a user device for use with server systems
US7683835B2 (en) 2006-08-15 2010-03-23 Computer Associates Think, Inc. System and method for locating wireless devices
US7817084B2 (en) 2006-08-23 2010-10-19 Qualcomm Incorporated System and/or method for reducing ambiguities in received SPS signals
US7822427B1 (en) 2006-10-06 2010-10-26 Sprint Spectrum L.P. Method and system for using a wireless signal received via a repeater for location determination
US7856234B2 (en) 2006-11-07 2010-12-21 Skyhook Wireless, Inc. System and method for estimating positioning error within a WLAN-based positioning system
US20080111737A1 (en) 2006-11-15 2008-05-15 Motorola Inc. Method and system for hybrid location aiding for multi-mode devices
KR100844349B1 (en) 2006-12-01 2008-07-07 삼성전자주식회사 Apparatus and method for searching wlan in portable terminal
JP2008139247A (en) 2006-12-05 2008-06-19 Alpine Electronics Inc Gps positioning device
US8314736B2 (en) 2008-03-31 2012-11-20 Golba Llc Determining the position of a mobile device using the characteristics of received signals and a reference database
US8193978B2 (en) 2007-11-14 2012-06-05 Golba Llc Positioning system and method using GPS with wireless access points
US7848733B2 (en) 2006-12-28 2010-12-07 Trueposition, Inc. Emergency wireless location system including a location determining receiver
US8000276B2 (en) 2007-02-05 2011-08-16 Wefi, Inc. Providing easy access to radio networks
US20080234533A1 (en) 2007-03-21 2008-09-25 Precision Innovations Llc System for evaluating an environment
US20080248741A1 (en) 2007-04-05 2008-10-09 Farshid Alizadeh-Shabdiz Time difference of arrival based estimation of direction of travel in a wlan positioning system
US20080248808A1 (en) 2007-04-05 2008-10-09 Farshid Alizadeh-Shabdiz Estimation of position, speed and bearing using time difference of arrival and received signal strength in a wlan positioning system
US8103285B2 (en) 2007-04-19 2012-01-24 Kyocera Corporation Apparatus, system and method for determining a geographical location of a portable communication device
US7724612B2 (en) 2007-04-20 2010-05-25 Sirf Technology, Inc. System and method for providing aiding information to a satellite positioning system receiver over short-range wireless connections
US7577441B2 (en) 2007-06-27 2009-08-18 Motorola, Inc. Method and device for determining a position of a portable electronic device
EP2034661A1 (en) 2007-09-07 2009-03-11 Deutsche Telekom AG Method and system for distributed, localized authentication in the framework of 802.11
US8331898B2 (en) 2007-10-03 2012-12-11 Texas Instruments Incorporated Power-saving receiver circuits, systems and processes
US8331335B2 (en) 2007-10-22 2012-12-11 Marvell World Trade Ltd. Location aware background access point scanning for WLAN
US8559575B2 (en) 2007-12-19 2013-10-15 Apple Inc. Microcontroller clock calibration using data transmission from an accurate third party
US7595754B2 (en) 2007-12-24 2009-09-29 Qualcomm Incorporated Methods, systems and apparatus for integrated wireless device location determination
US8761133B2 (en) 2008-01-14 2014-06-24 Nokia Corporation Use of movement information about a wireless client
US20090189810A1 (en) 2008-01-24 2009-07-30 Broadcom Corporation Weighted aiding for positioning systems
WO2009099773A2 (en) 2008-02-01 2009-08-13 Walker Jonathan B Systems and methods for providing location based services (lbs) utilizing wlan and/or gps signals for seamless indoor and outdoor tracking
US8018950B2 (en) 2008-03-17 2011-09-13 Wi-Lan, Inc. Systems and methods for distributing GPS clock to communications devices
US7602334B1 (en) 2008-04-03 2009-10-13 Beceem Communications Inc. Method and system of a mobile subscriber estimating position
EP2283641B1 (en) 2008-06-06 2020-08-12 Skyhook Wireless, Inc. Method and system for determining location using a hybrid satellite and wlan positioning system by selecting the best wlan-ps solution
US8155666B2 (en) 2008-06-16 2012-04-10 Skyhook Wireless, Inc. Methods and systems for determining location using a cellular and WLAN positioning system by selecting the best cellular positioning system solution
JP2010054469A (en) * 2008-08-29 2010-03-11 Pioneer Electronic Corp Current position detector, current position detection method, and program for current position detection
US9155017B2 (en) 2009-02-03 2015-10-06 Kyocera Corporation Access point detection for wireless networking
EP2237527A1 (en) 2009-03-31 2010-10-06 Thomson Licensing Method and apparatus for determining location information
US8022877B2 (en) 2009-07-16 2011-09-20 Skyhook Wireless, Inc. Systems and methods for using a satellite positioning system to detect moved WLAN access points
US8063820B2 (en) 2009-07-16 2011-11-22 Skyhook Wireless, Inc. Methods and systems for determining location using a hybrid satellite and WLAN positioning system by selecting the best SPS measurements
WO2011008613A1 (en) 2009-07-16 2011-01-20 Skyhook Wireless, Inc. Systems and methods for using a hybrid satellite and wlan positioning system
US20110021207A1 (en) 2009-07-24 2011-01-27 Morgan Edward J System and Method for Estimating Positioning Error Within a WLAN-Based Positioning System
US8406785B2 (en) 2009-08-18 2013-03-26 Skyhook Wireless, Inc. Method and system for estimating range of mobile device to wireless installation
US8638256B2 (en) 2009-09-29 2014-01-28 Skyhook Wireless, Inc. Accuracy and performance of a hybrid positioning system
WO2011041430A1 (en) 2009-10-02 2011-04-07 Skyhook Wireless, Inc. Determining position in a hybrid positioning system using a dilution of precision metric
US8279114B2 (en) 2009-10-02 2012-10-02 Skyhook Wireless, Inc. Method of determining position in a hybrid positioning system using a dilution of precision metric
US20110080318A1 (en) 2009-10-02 2011-04-07 Skyhook Wireless, Inc. Determining A Dilution of Precision Metric Using Two or Three GPS Satellites
US8106818B2 (en) * 2009-12-31 2012-01-31 Polaris Wireless, Inc. Positioning system and positioning method
US8619643B2 (en) 2010-03-24 2013-12-31 Skyhook Wireless, Inc. System and method for estimating the probability of movement of access points in a WLAN-based positioning system
US8700053B2 (en) 2010-06-11 2014-04-15 Skyhook Wireless, Inc. Systems for and methods of determining likelihood of relocation of reference points in a positioning system
US8606294B2 (en) 2010-10-05 2013-12-10 Skyhook Wireless, Inc. Method of and system for estimating temporal demographics of mobile users
KR101972606B1 (en) 2010-11-03 2019-04-25 스카이후크 와이어리스, 인크. Method of system for increasing the reliability and accuracy of location estimation in a hybrid positioning system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7660588B2 (en) * 2002-10-17 2010-02-09 Qualcomm Incorporated Method and apparatus for improving radio location accuracy with measurements
US7151939B2 (en) * 2003-02-18 2006-12-19 Qualcomm Incorporated Method, apparatus, and machine-readable medium for providing indication of location service availability and the quality of available location services
US6975266B2 (en) * 2003-06-17 2005-12-13 Global Locate, Inc. Method and apparatus for locating position of a satellite signal receiver
US20060049982A1 (en) * 2004-09-03 2006-03-09 Telefonaktiebolaget L M Ericsson (Publ) Method of and system for reducing a time to fix in a location-enabled receiver
US20080291086A1 (en) 2007-05-25 2008-11-27 Broadcom Corporation Position determination using available positioning techniques
US20090192709A1 (en) 2008-01-25 2009-07-30 Garmin Ltd. Position source selection
US20100039323A1 (en) * 2008-08-12 2010-02-18 Andrei Kosolobov Method and system for global position reference map (gprm) for agps

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP2635915A4

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8638725B2 (en) 2008-06-16 2014-01-28 Skyhook Wireless, Inc. Methods and systems for determining location using a cellular and WLAN positioning system by selecting the best WLAN PS solution
US8462745B2 (en) 2008-06-16 2013-06-11 Skyhook Wireless, Inc. Methods and systems for determining location using a cellular and WLAN positioning system by selecting the best WLAN PS solution
US10031237B2 (en) 2009-07-16 2018-07-24 Skyhook Wireless, Inc. Techniques for selecting SPS measurements to use in determining a final location estimate based on a WLAN-based location estimate
US8564481B2 (en) 2009-07-16 2013-10-22 Skyhook Wireless, Inc. Systems and methods for using a satellite positioning system to detect moved WLAN access points
US9013350B2 (en) 2009-07-16 2015-04-21 Skyhook Wireless, Inc. Systems and methods for using a satellite positioning system to detect moved WLAN access points
US8638256B2 (en) 2009-09-29 2014-01-28 Skyhook Wireless, Inc. Accuracy and performance of a hybrid positioning system
US8890746B2 (en) 2010-11-03 2014-11-18 Skyhook Wireless, Inc. Method of and system for increasing the reliability and accuracy of location estimation in a hybrid positioning system
US9135802B2 (en) 2012-05-24 2015-09-15 Google Inc. Hardware attitude detection implementation of mobile devices with MEMS motion sensors
US9348434B2 (en) 2012-11-21 2016-05-24 Google Technology Holdings LLC Low power management of multiple sensor integrated chip architecture
US9354722B2 (en) 2012-11-21 2016-05-31 Google Technology Holdings LLC Low power management of multiple sensor integrated chip architecture
US9329701B2 (en) 2012-11-21 2016-05-03 Google Technology Holdings LLC Low power management of multiple sensor chip architecture
JP2016522391A (en) * 2013-03-15 2016-07-28 クアルコム,インコーポレイテッド Energy saving device for geofence applications
US9697465B2 (en) 2014-04-30 2017-07-04 Google Technology Holdings LLC Drawing an inference of a usage context of a computing device using multiple sensors

Also Published As

Publication number Publication date
EP2635915A1 (en) 2013-09-11
US8890746B2 (en) 2014-11-18
KR20130117800A (en) 2013-10-28
EP2635915B1 (en) 2016-05-18
EP2635915A4 (en) 2014-03-26
KR101972606B1 (en) 2019-04-25
JP2014501912A (en) 2014-01-23
US20120112958A1 (en) 2012-05-10

Similar Documents

Publication Publication Date Title
US8890746B2 (en) Method of and system for increasing the reliability and accuracy of location estimation in a hybrid positioning system
US10031237B2 (en) Techniques for selecting SPS measurements to use in determining a final location estimate based on a WLAN-based location estimate
US8089398B2 (en) Methods and systems for stationary user detection in a hybrid positioning system
US8063820B2 (en) Methods and systems for determining location using a hybrid satellite and WLAN positioning system by selecting the best SPS measurements
US9733361B2 (en) Low power positioning techniques for mobile devices
WO2011008613A1 (en) Systems and methods for using a hybrid satellite and wlan positioning system
AU2009255955B2 (en) Method and system for determining location using a hybrid satellite and WLAN positioning system by selecting the best WLAN-PS solution
AU2012200417B2 (en) Method and system for determining location using a hybrid satellite and WLAN positioning system by selecting the best WLAN-PS solution

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11838809

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2013537820

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 2011838809

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 20137014037

Country of ref document: KR

Kind code of ref document: A