WO2015165673A1

WO2015165673A1 - Communication node, alarm system and method for handling alarm notifications

Info

Publication number: WO2015165673A1
Application number: PCT/EP2015/056888
Authority: WO
Inventors: Martin REIDEVALL; David Karlsson; Per-Ludvig Normark
Original assignee: Skygd Ab
Priority date: 2014-05-02
Filing date: 2015-03-30
Publication date: 2015-11-05

Abstract

A communication node (110) receives alarm notifications (N[121;GP1;ID1], N[122;GP2]) from mobile terminals (121; 122) via a network interface (110N). Each alarm notification (N[121; GP1;ID1], N[122;GP2]) contains a first data field configured to contain information based upon which a symbolic position (ID1) is derivable, and a second data field configured to contain information describing a geographic position (GP1, GP2) for the mobile terminal (121; 122) from which the alarm notification was originated; the symbolic position (ID1) being a label associated with a well-defined physical area (131). A central unit (110C) processes each alarm notification (N[121;GP1;ID1], N[122;GP2]) by: (a) checking if the first data field contains a first data string, and if so deriving a symbolic position (ID1) there from; (b) checking if the second data field contains a second data string, and if so extracting a latest registered geographic position (GP1, GP2) there from; and (c) generating presentation data (DP) based on any of said latest registered geographic position (GP) and/or symbolic position (ID1). A presentation interface (110P) then forwards the presentation data (DP) for presentation on a human-comprehensible format via at least one presentation unit (115).

Description

Communication Node, Alarm System and Method for Handling Alarm Notifications

THE BACKG ROUN D OF THE I NVENTION AN D PRIOR ART

The present invention relates generally to solutions for handling distress alarms from mobile terminals. More particularly the invention relates to a communication node according to the preamble of claim 1 , an alarm system according to the preamble of claim 3 and a method according to the preamble of claim 1 1 . The invention also relates to a computer program product according to claim 14 and a computer readable mediu m according to claim 1 5.

Today's positioning functions i n low-cost consumer products, such as mobile telephones enable a wide variety of services and applications. For example map and navigation applications are offered conveniently and at very low cost. Moreover, in addition to assisti ng a mobile user directly, the position data generated in a mobile terminal may be used to notify others, for i nstance in connection with an emergency situation. Thereby, i n case of an accident, or if the user is subjected to an assault, an alarm noti- fication can be sent out, which informs a receiver of where the person in distress is located .

US 201 3/0332273 discloses a positioning system for determi ning the location of a portable device. Here, a radio network includes radio network nodes for commu nicating with the portable device and measuring signal strength from the portable device. The radio network also i ncludes a Near Field Commu nication node for communicating with the portable device and at least ini tially providing the portable device with configuration i nformation to enable the portable device to pair with the radio network no- des. The system also i ncludes a positioning server for receivi ng sig nal strength information from the radio network, determi ning a location of the portable device, providi ng the portable device with a graphical representation of its location within a floor plan, receiving an indication of a desired product from the portable device, determi ning a location of the product, calculating and providing the portable device with a route from the location of the portable device to the product.

US 7,924, 1 49 presents a method for guidi ng people around urban environments indoor and outdoor, and for providing accu rate update and real ti me emergency notification and information to the building occupants or to the emergency designated areas. Real ti me emergency information is thereby provided as well as navigation along an emergency exit route. The information is received directly and displayed on an existing cellular phone as Bluetooth application.

US 8,61 1 ,321 describes a location tracking system , wherein transmitter tags are disposed throughout an area where the location tracking is carried out. The transmitter tags are configu red to transmit their unique identifiers. A personal radio com mu nication device being tracked detects a u nique identifier recei ved from a transmitter tag and transmits the detected unique identifier to a server. The server links a known physical location associated with the unique identifier to an identifier of the personal radio com munication device so as to carry out location tracking .

PROBLEMS ASSOCIATED WITH TH E P R IOR ART

Although each of the above solutions may be associated with specific advantageous features technical obstacles remain to be overcome. For example, there is yet no system that ensures reliable positioning of a user in distress irrespective of whether he/ she is located within the range of conventional positioni ng sys- terns (i .e. satellite and/or cellular-based systems) or inside a building , which prevents contact with such systems ; and at the same time, does not unnecessarily jeopardize the integrity of the user. SUMMARY OF TH E I NVENTION

The object of the present invention is therefore to solve the above problem , and offer a simple and reliable handling of alarm notifications from mobile terminals. According to one aspect of the invention, the object is achieved by the initially described communication node, wherein each alarm notification has first and second data fields. The first data field is configured to contain i nformation based upon which a symbolic position is derivable. The symbolic position is a label that is associated with a well-defi ned physical area (e.g . a particular room) . The second data field is configured to contain information describing a geographic position (e.g . in terms of coordinates) for the mobile terminal from which the alarm notification was origi nated. Specifically, the central unit is configured to pro- cess the alarm notifications by, for each notification : (a) check if the first data field contains a first data string , and if so derive a symbolic position there from ; (b) check if the second data field contains a second data string , and if so extract a latest registered geographic position there ; and (c) generate presentation data based on any of said latest registered geographic position and/or said symbolic position.

This communication node is advantageous because it is capable of providing hig h-quality positioni ng for all mobile terminals even if they may be outside the range of conventional positioning sys- terns. Furthermore, the communication node does not collect any superfluous roaming data, i .e. if no alarm notification is issued , no data are forwarded to the communication node . Thus, there is no unnecessary violation of the users' integrity.

According to one preferred embodiment of this aspect of the in - vention, the information of the first data string is unique for each well-defined physical area (e.g . each room of a particular building has its own identity) , and the com munication node is commu nicatively connected to a database holding a set of the data strings which for each data string refers to a particu lar well-defi- ned physical area. Thus, based on the alarm notification , the commu nication node may conveniently look up from which physical area (or room) the alarm notification was originated .

According to another aspect of the i nvention, the object is achie- ved by an alarm system containing the above-proposed communication node and at least one mobile terminal , which is configured to generate an alarm notification in response to a trigger event. The mobile termi nal is further configured to send the alarm notification to the commu nication node. Consequently, the same advantages are attainable as via the communication node discussed above.

According to one preferred embodiment of this aspect of the invention, the at least one mobile terminal is configured to initiate the trigger event based on a user action performed i n respect of the mobile terminal , for instance by pushing a button on the terminal . Thereby, alarms may be initiated manually. Alternatively, or as a complement, the mobile terminal is configured to initiate the trigger event based on an involuntary user action, such as i n response to the user tripping/falling , which may be registered by an accelerometer in the mobile termi nal ; or even in response to a non-action from the user, i .e. if no acceleration is registered by the mobile termi nal within a threshold ti me limit (which, in this case, is interpreted as the user having fainted, or by other means is i ncapacitated) . According to another preferred embodi ment of this aspect of the invention, the at least one mobile terminal is configured to initiate the trigger event based on a remote message origi nated by a node being external to the mobile termi nal and received in the mobile terminal . Thus, automatic, or semi-automatic alarms can be generated. Moreover, the external node may be represented by a portable unit (e.g . a remote control) carried by the user. Thus, by for example pushing a button on the portable unit, the user can discretely generate a remote message, which initiates the trigger event. For instance, the remote message may be forwarded via a Bluetooth or BLE i nterface to the mobile terminal .

According to a further preferred embodiment of this aspect of the invention , the alarm system contains a set of beacon units each of which is configured to repeatedly broadcast a respective signal contai ning data indicative of the first data string . Moreover, the mobile terminal is configured to receive the broadcast a sig nal , and based thereon generate data to be in cluded in the first data field. This means that the alarm system can be set up without any coordination between the beacon units. I nstead , the beacon units may operate completely i ndependent from one another. Naturally, this renders the overall design of the system especially u ncomplicated.

According to yet another preferred embodi ment of this aspect of the invention, if the mobile terminal receives more than one broadcast sig nal (i .e. from two or more bacon units) , the mobile termi nal is configured to generate the data to be i ncluded in the first data field based on a broadcast signal received in the mobile termi nal , which, according to at least one test crite rion checked in the mobile terminal , is deemed to origi nate from the beacon unit being nearest to the mobile terminal . For example the test criterion may thus relate to a measure sig nal strength. As a result, any alarm-generating mobile terminals can be located i n a highly straightforward manner. According to another preferred embodi ment of this aspect of the invention , if the first data field at a first poi nt in time contains in formation that is different from updated data which have been generated based on a latest received broadcast sig nal associated with a beacon unit deemed to be nearest to the mobile ter- minal , the mobile terminal is further configured to replace the contents of the first data field with the updated data at a poi nt i n time after the fi rst point in ti me. Further, the mobile termi nal is configured to receive time/position signals from a set of sig nal sources (e.g . space vehicles) , based thereon determine a current geographic position for the mobile terminal , and store information describi ng the determined current geographic position in the second data field. Analogously, if the second data field, at a second point in time, contai ns information that is different from updated data which have been generated based on the received time/position signals, the mobile termi nal is configu red to add the updated data to the contents of the second data field after the second point i n ti me. Thereby, the positioning data is always kept up to date in the mobile termi nal . According to still another aspect of the invention , the object is achieved by the method described initially, wherein each of the alarm notifications has respective first and second data fields. The first data filed is configured to contain information based upon which a symbolic position is derivable, which symbolic position is a label associated with a well-defined physical area (e.g . a room of a building) . The second data field is configured to contai n information describing a geographic position for the mobile terminal from which the particular alarm notification was originated . The method i nvolves processing the alarm notifica- tions by, for each notification : (a) checking if the first data field contains a first data string , and if so derivi ng a symbolic position there from ; (b) checking if the second data field contains a second data string , and if so extracting a latest registered geographic position there from ; and (c) generating presentation data based on the latest registered geographic position and any derived symbolic position. The advantages of this method, as well as the preferred embodi ments thereof , are likewise apparent from the discussion above with reference to the proposed system . According to a further aspect of the inve ntion the object is achieved by a computer program product, which is loadable into the memory of a computer, and includes software adapted to implement the method proposed above when said computer program product is ru n on a computer. According to another aspect of the invention the object is achieved by a computer readable medium, having a program recorded thereon, where the program is to control a computer to perform the method proposed above when the program is loaded into the computer.

Further advantages, beneficial features and applications of the present invention will be apparent from the following description and the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now to be explained more closely by means of preferred embodiments, which are disclosed as examples, and with reference to the attached drawings.

Figure 1 shows a block diagram over an exemplary alarm system in which the proposed communication no- de is included; and

Figure 2 contains a flow diagram illustrating the general method according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Figure 1 illustrates the invention via an example in the form of an alarm system including a communication node 110, mobile terminals 121 and 122, and a network 120 connecting the mobile terminals 121 and 122 to the communication node 110.

The communication node 110 is configured to handle alarms (e.g. relating to assault and/or care situations) from the mobile terminals 121 and 122. To this aim, the communication node 110 includes a network interface 11 ON, a central unit 110C and a presentation interface 11 OP.

The network interface 11 ON is configured to receive alarm notifi- cations N[121 ;GP1 ;ID1 ], N[122;GP2] from mobile terminals. In Figure 1, the reference labels 121 and 122 exemplify first and second mobile terminals respectively. The central unit 110C is configured to process the alarm notifications N[121 ;GP1 ;ID1 ] and N[122;GP2], and based thereon generate presentation data DP. The presentation interface 110P is configured to be connected to at least one presentation unit 115, such as a computer provided with a display, on which the presentation data DP is presentable on a human-comprehensible format (e.g. in graphics, text and/or acoustically). Thereby, an officer in a support center may efficiently direct personnel to assist a user of the mobile terminal 121 or 122 from which the alarm notification N[121 ;GP1 ;ID1] or N[122;GP2] respectively was originated. Alternatively, or as a complement, provided adequate connection to the presentation interface 110P, another mobile-terminal user can be guided to the originator of the alarm notification N[121 ;GP1 ;ID1] or N[122;GP2] based on the presentation data DP.

According to the invention, each alarm notification N[121;GP1; ID1] and N[122;GP2] includes first and second data fields. The first data field may be empty, but the second data field should always contain data (either fresh, or more or less dated).

The first data field is configured to contain information based upon which a symbolic position ID1 is derivable. The symbolic position ID1 is a label (e.g. a unique identity) associated with a well-defined physical area, such as a specific room 131 in a particular building 130. The second data field is configured to contain information describing a geographic position GP1 or GP2 (e.g. X and Y values, latitude and longitude etc. in a geographic coordinate system) for the mobile terminal 121 and 122 respectively from which the alarm notification was originated.

The central unit 110C is configured to process the alarm notifications N[121;GP1;ID1] and N[122;GP2] by, for each incoming alarm notification, execute the following procedure.

(a) Check if the first data field contains a first data string, and if so derive a symbolic position ID1 there from (cf. the first mobile terminal 121 located in room 131).

(b) Check if the second data field contains a second data string, and if so extract a latest registered geographic posi- tion GP1 and GP2 there from, and

(c) Generate presentation data DP based on any of said latest registered geographic position GP1 and GP2 respectively, and/or said symbolic position ID1.

Preferably, the information of the first data string is a unique piece of information (e.g. an identity or a name tag) for a respective well-defined physical area, such as a room 131, 132 or 133 in a building 130. In Figure 1, we see a schematic building

130, where a first beacon unit 141 is arranged in a first room

131, a second beacon unit 142 is arranged in second room 132 and a third beacon unit 143 is arranged in third room 133. Each beacon unit 141, 142 and 143 repeatedly broadcasts a respective signal containing data indicative of a first data string ID1, ID2 and ID3 respectively, which first data string is unique for each of the well-defined physical areas 131, 132 and 133. The signals may be broadcast via Bluetooth, BLE (Bluetooth Low Energy), WiFi, or on similar wireless format.

The first and second mobile terminals 121 and 122 are configured to receive the broadcast signals, and based thereon generate the first data string to be included in the first data field. According to one preferred embodiment of the invention, the communication node 110 is communicatively connected to a database 117, which contains a set of data strings that for each first data string refers to a particular well-defined physical area, e.g. the rooms 131, 132 and 133. Thus, by consulting the data- base 117, the communication node 110 may associate a mobile terminal 121 from which an alarm notification has been received with a particular room 131 in the building 130 based on the first data string ID1 in the first data filed. In the example represented in Figure 1, the first mobile terminal

121 is located inside the building 130, where it cannot receive any signals from conventional positioning systems (here exemplified by a global navigation satellite system and a cellular-based communication system capable of positioning its associated mobile terminals via triangulation); and the second mobile terminal

122 is located outside the building 130, where it can receive signals from at least one of space vehicles 161, 162, 163 and 164 in the global navigation satellite system and a base station 150 of the cellular-based communication system. It is further presumed that, at some earlier point in time, the first mobile terminal 121 was located at a position where it could derive a geographic position GP1 based on the signals from the space vehicles 161, 162, 163 and 164 in the global navigation satellite system and/or a base station 150 of the cellular-based communication system. Therefore, also the second data field of the alarm notification N[121 ; GP1;ID1] from the first mobile terminal 121 contains a second data string indicative of a latest registered geographic position GP1 (i.e. that was derived when the first mobile termi- nal 121 was in contact with a conventional positioning system).

Nevertheless, the reverse does not apply, i.e. since the second mobile terminal 122 is presently located outside of the building 130, we assume that it cannot be reached by any of the broadcasts signals containing data indicating the first data strings ID1, ID2 or ID3. Therefore, the second data field of the alarm notification N[122;GP2] from the second mobile terminal 122 is empty.

However, according to the invention, if a mobile terminal should be located at a position where it simultaneously receives a broadcast signal (e.g. from the beacon units 141, 142 and/or 143) and signals from one or more conventional positioning systems its alarm notification will contain a data string being up-to- date both in the first and second data fields.

Nevertheless, if the mobile terminal, say the first terminal 121, receives more than one broadcast signal, it is preferably configured to generate the data to be included in the first data field exclusively based on the broadcast signal received in the mobile terminal 121, which, according to at least one test criterion checked in the mobile terminal 121, is deemed to originate from the beacon unit being nearest to the mobile terminal 121 , say the first beacon unit 141 in the first room 131. Namely, depending on the mobile terminal's 121 position and the radio environment it cannot be excluded that two or more broadcast signals are detectable simultaneously. In such a situation it is normally desirable to discard the less relevant broadcast signals, and tie the mobile terminal 121 to a single well-defined physical area 131, so that for example personnel sent out to assist the user of the mobile terminal 121 may be led to a destination being as specific as possible.

According to one preferred embodiment of the invention, the mobile terminals 121 and 122 are configured to generate the alarm notification N[121 ;GP1 ;ID1 ] and N[122;GP2] respectively in response to a trigger event, and then send the alarm notifications N[121 ;GP1 ;ID1] and N[122;GP2] to the communication node 110. The trigger event, in turn, may either be initiated based on a user action performed in respect of the mobile terminal 121 or 122 (e.g. activating an alarm button, uttering a pre-defined voice command), or based on a remote message. The remote message is originated by a node (not shown) external to the mobile terminal 121 or 122 and received in the mobile terminal 121 and 122, thus causing the trigger event. The external node may here implement a surveillance service interrogating a current status the mobile terminal 121 or 122. Alternatively, or as a supplement thereto, the external node may be represented by a portable unit (e.g. a remote control) carried by the user. Thus, the alarm activating button on the mobile terminal may be doubled or replaced by a button on the portable unit. This enables the user to discretely generate a remote mes- sage, which, in turn initiates the trigger event. The remote message may be sent from the portable unit to the mobile terminal via a Bluetooth interface, a BLE interface, or any short- range interface. To keep the data strings in the first and second data fields as up-to-date as possible, the following strategies are preferably applied in the mobile terminals 121 and 122.

If a mobile terminal, say the first mobile terminal 121 , is located within the reach of at least one beacon unit, and the first data field, at a first point in time, contains information that is different from updated data, which have been generated based on a latest received broadcast signal associated with a beacon unit, say 141, that is now deemed to be nearest to the mobile terminal 121; the mobile terminal is configured to replace the con- tents of the first data field with the updated data (i.e. at a point in time after the first point in time).

Analogously, if a mobile terminal, say the second mobile terminal 122, is located within the reach of at least one conventional positioning system, the mobile terminal 122 is preferably configured to receive time/position signals from a set of signal sources 150 and/or 161, 162, 163 and 164, based thereon determine a current geographic position GP2 for the mobile terminal 122, and store information describing the determined current geographic position GP2 in the second data field. Any previously registered data in the second data field is thereby overwritten. In other words, if the second data field, at a second point in time, contains information that is different from updated data which have been generated based on currently received time/position signals, the mobile terminal 122 is preferably configured to add the updated data to the contents of the second data field after the second point in time.

Preferably, the communication node 110 contains, or is in communicative connection with a memory unit 110M storing a com- puter program product, which contains software for making the central unit 1 1 OP execute the above-described actions when the computer program product is run on the central u nit 1 1 0 P.

To sum up, and with reference to the flow diag ram in Figure 2, we will now describe the general method of handling an alarm , which is performed in the proposed commu nication node 1 1 0.

A first step 21 0 checks if an alarm notification from a mobile termi nal has been received, and if so, steps 220 and 230 follow. Otherwise, the procedure loops back and stays in step 21 0. I n step 220 , the alarm notification is processed by checking if its first data field contains a first data string , and if so a step 240 follows. Otherwise, the procedure continues to a step 260.

I n step 230, the alarm notification is processed by checking if its second data field contains a second data stri ng , and if so a step 250 follows. Otherwise, the procedure contin ues to step 260.

I n step 240, a symbolic position is derived, which is a label associated with a well-defined physical area, such as a particular part of a given edifice.

I n step 250 , a latest registered geographic position in the mobile termi nal is extracted from the second data field of the alarm notification.

I n step 260 , presentation data are generated based on any of said latest registered geographic position and/or symbolic position derived i n steps 250 and 240 respectively. Thus, theoreti- cally, if both the first and second data strings are empty, it is possible that no data at all is presented i n step 260. However, in essentially every practical implementation, there will always be some second data stri ng (of some age) in the second data field.

Subsequently, in a step 270, the presentation data are presen- ted on a hu man-comprehensible format, preferably via a presentation means (e.g . a computer display and/or a loudspeaker) connected to a presentation interface of the commu nication node 1 1 0. Consequently, optimal conditions are created for locali zing the user who sent the alarm notification. Namely, if he/she is positioned outdoors, an adequate geographic position will be presented ; and if he/she is positioned inside a buildi ng , the building's geographic position will be presented along with an i ndi cation of i n which room , or part of the building he/she is located.

Then, preferably, after step 270 the procedure loops back to steps 220 and 230 to check if updated data have been produced in respect of the symbolic and/or geographic position , i .e. if any additional first and/or second data string has been received relating to the alarm notification . Thus, also after having presented initial data relating to a particular alarm notification , an operator may continue to obtain im portant information regardi ng any changes in the location of the person who initiated the alarm .

All of the process steps, as well as any sub-sequence of steps, described with reference to Figure 2 above may be controlled by means of a programmed computer apparatus. Moreover, although the embodi ments of the invention described above with reference to the drawings comprise a computer apparatus and processes performed in a computer apparatus, the i nvention thus also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice. The program may be in the form of source code, object code, a code intermediate source and object code such as in partially compiled form , or in any other form suitable for use in the implementation of the process according to the invention. The program may either be a part of an operating system , or be a separate application. The carrier may be any entity or device capable of carrying the program . For example, the carrier may comprise a storage medium , such as a Flash memory, a ROM (Read Only Memory) , for example a DVD ( Digital Video/ Versatile Disk) , a CD (Compact Disc) or a semiconductor ROM , an EP- ROM (Erasable Programmable Read-Only Memory) , an EEPROM (Electrically Erasable Program mable Read-Only Memory) , or a magnetic recording medium , for example a floppy disc or hard disc. Further, the carrier may be a transmissible carrier such as an electrical or optical signal which may be conveyed via electrical or optical cable or by radio or by other means. When the program is embodied in a signal which may be conveyed directly by a cable or other device or means, the carrier may be constituted by such cable or device or means. Alternatively, the carrier may be an integrated circuit in which the prog ram is embedded, the integrated circuit being adapted for performing , or for use in the performance of, the relevant processes.

The term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components. However, the term does not preclude the presence or addition of one or more additional features, i nte- gers, steps or components or groups thereof.

The invention is not restricted to the described embodiments in the figures, but may be varied freely within the scope of the claims.

Claims

1. A communication node (110) for handling alarms, the communication node (110) comprising:

a network interface (11 ON) configured to receive alarm no- tifications (N[121 ;GP1 ;ID1], N[122;GP2]) from mobile terminals (121; 122);

a central unit (110C) configured to process the alarm notifications (N[121 ;GP1 ;ID1], N[122;GP2]), and based thereon generate presentation data (DP); and

a presentation interface (11 OP) configured to be connected to at least one presentation unit (115) in which the presentation data (DP) is presentable on a human-comprehensible format, characterized in that

each of said alarm notifications (N[121 ;GP1 ;ID1], N[122; GP2]) comprises a first data field configured to contain information based upon which a symbolic position (ID1) is derivable, the symbolic position (ID1) being a label associated with a well-defined physical area (131); and a second data field configured to contain information describing a geographic position (GP1, GP2) for the mobile terminal (121; 122) from which the alarm notification was originated; and the central unit (110C) is configured to process the alarm notifications (N[121 ;GP1 ;ID1], N[122;GP2]) by for each notification:

(a) check if the first data field contains a first data string, and if so derive a symbolic position (ID1) there from;

(b) check if the second data field contains a second data string, and if so extract a latest registered geographic position (GP1, GP2) there from, and

(c) generate presentation data (DP) based on any of said latest registered geographic position (GP1, GP2) and/or said symbolic position (ID1).

2. The communication node (110) according to claim 1, wherein the information of the first data string (ID1, ID2, ID3) is unique for each of said well-defined physical areas (131, 132; 133), and the communication node (110) is communicatively con- nected to a database (117) comprising a set of said data strings which for each of said data strings refers to a particular well-defined physical area (131, 132, 133).

3. An alarm system, comprising the communication node (110) according to any one of claims 1 or 2 and at least one mobile terminal (121, 122) which is configured to generate an alarm notification (N[121 ;GP1 ;ID1], N[122;GP2]) in response to a trigger event, and send the alarm notification (N[121 ;GP1 ;ID1], N[122;GP2]) to the communication node (110).

4. The alarm system according to claim 3, wherein the at least one mobile terminal (121, 122) is configured to initiate the trigger event based on a user action performed in respect of the mobile terminal (121, 122).

5. The alarm system according to any one of claims 3 or 4, wherein the at least one mobile terminal (121, 122) is configured to initiate the trigger event based on a remote message originated by a node external to the mobile terminal (121, 122) and received in the mobile terminal (121 , 122).

6. The alarm system according to any one of claims 3 to 5, comprising a set of beacon units (141, 142, 143), which each is configured to repeatedly broadcast a respective signal containing data indicative of said first data string (ID1, ID2; ID3); the mobile terminal (121, 122) being configured to receive the broadcast a signal, and based thereon generate data to be in- eluded in the first data field.

7. The alarm system according to claim 6, wherein, if the mobile terminal (121) receives more than one broadcast signal, the mobile terminal (121) is configured to generate the data to be included in the first data field based on a broadcast signal recei- ved in the mobile terminal (121), which, according to at least one test criterion checked in the mobile terminal (121), is deemed to originate from a beacon unit (141) being nearest to the mobile terminal (121).

8. The alarm system according to any one of claims 6 or 7, wherein, if the first data field at a first point in time contains information that is different from updated data which have been generated based on a latest received broadcast signal associated with a beacon unit (141) deemed to be nearest to the mobile terminal (121), the mobile terminal (121) is configured to replace the contents of the first data field with the updated data at a point in time after the first point in time.

9. The alarm system according to any one of claims 3 to 8, wherein the mobile terminal (122) is configured to receive time/ position signals from a set of signal sources (150, 161, 162, 163, 164), based thereon determine a current geographic position (GP2) for the mobile terminal (122), and store information describing the determined current geographic position (GP2) in the second data field.

10. The alarm system according to claim 9, wherein if the second data field at a second point in time contains information that is different from updated data which have been generated based on the received time/position signals, the mobile terminal (122) is configured to add the updated data to the contents of the second data field after the second point in time.

11. A method of handling alarms, comprising:

receiving, in a communication node (110), alarm notifica- tions (N[121 ;GP1 ;ID1], N[122;GP2]) from mobile terminals (121; 122);

processing the alarm notifications (N[121 ;GP1 ;ID1], N[122; GP2]), based thereon

generating presentation data (DP); and

presenting the presentation data (DP) on a human-comprehensible format,

characterized by the alarm notifications (N[121 ;GP1 ;ID1], N[122;GP2]) comprising a first data field configured to contain information based upon which a symbolic position (ID1) is derivable, the symbolic position (ID1) being a label associated with a well-defined physical area (131); and a second data field configured to contain information describing a geographic position (GP1, GP2) for the mobile terminal (121; 122) from which the particular alarm notification was originated; and the method comprising:

processing the alarm notifications (N[121 ;GP1 ;ID1], N[122; GP2]) by for each notification:

(a) checking if the first data field contains a first data string, and if so deriving a symbolic position (ID1) there from;

(b) checking if the second data field contains a second data string, and if so extracting a latest registered geographic position (GP1, GP2) there from, and

(c) generating presentation data (DP) based on any of said latest registered geographic position (GP1, GP2) and/or symbolic position (ID1).

12. The method according to claim 11, wherein the data string is unique for each of said well-defined physical areas (131, 132, 133), and the method further comprising linking each of said data strings to a corresponding well-defined area (131, 132, 133).

13. The communication node (110), alarm system or method according to any one of the preceding claims, wherein the alarm notifications (N[121 ;GP1 ;ID1], N[122;GP2]) are embodied in at least one of and Internet-Protocol messages and short-message-service messages.

14. A computer program product loadable into the memory (110M) of a computer, comprising software for performing the steps of any of the claims 11 to 12 when the computer program product is run on the computer.

15. A computer readable medium (110M), having a program recorded thereon, where the program is to make a computer perform the steps of any of the claims 11 to 12.