CN101191833A - Radio frequency recognition indoor position finding and detection method based on receiving signal intensity - Google Patents

Abstract

The invention discloses a method for detecting radio frequency identification indoor positioning based on the received signal strength. The concrete way comprises the following steps: defining the vectors Si and theta i of the signal strength of each label to be positioned and each referential label respectively; using n card readers to acquire receiving signal strength of m referential labels; obtaining the Euclidean distance vector of a certain label to be detected by means of Euclidean distance measurement; finally positioning the label to be detected according to the principle that the measure of the distance between the label to be detected and the referential label closest to the label to be detected is the smallest. By the method, the a plurality of labels close to the label to be detected can be identified, and by means of the known coordinates of the identified labels close to the label to be detected, the position of the label to be detected can be obtained by deduction. The invention provides an effective two-dimension positioning algorithm and realizes the positioning of a mobile label by means of the referential labels indoor the positions of which is known.

Description

A kind of radio frequency recognition indoor position finding and detection method based on received signal intensity

Technical field

The present invention relates to a kind of (RFID) indoor position finding and detection method that is applicable to the indoor wireless location technology based on received signal intensity (RSS).

Background technology

RFID (radio-frequency (RF) identification) is a kind of non-contacting automatic identification technology, its ultimate principle is to utilize radiofrequency signal and space coupling (inductive coupling or electromagnetic coupled) transport property, realization is to being identified the automatic identification of object, have the unrivaled advantage of many traditional automatic identification technologies, as noncontact, distance, read-write, contain much information, need not manual intervention, multiple goal discerns etc. simultaneously.

The RSS parameter, received wireless signal strength when being RFID card reader label reading, usually measure with watt or dBm, it is a messaging parameter relevant with distance, and main flow rfid interrogator in the market all begins to support gradually directly to export the function of RSS intensity, is more prone to obtain than other messaging parameter.

Summary of the invention

The objective of the invention is to propose a kind of radio frequency recognition indoor position finding and detection method based on received signal intensity, this position finding and detection method has utilized RSS parameter easily collecting and with distance the characteristics of good correlation has been arranged, collect the RSS parameter of each label and carry out analyzing and processing, judgment criterion according to received signal intensity (RSS), search out several reference label the most similar, and treat positioning label according to the numerical relation of label to be positioned and these reference label and position to label to be positioned.Fully taken into account the statistical property of RFID indoor propagation mechanism and channel fading and the empirical model of energy loss, can position indoor RFID card reader label reading effectively.

The present invention is based on the RFID indoor position finding and detection method of RSS, utilized RSS parameter easily collecting and the characteristics of good correlation have been arranged with distance, collect the RSS parameter of each label and carry out analyzing and processing, judgment criterion according to this algorithm design, search out several reference label the most similar, and treat positioning label according to the numerical relation of label to be positioned and these reference label and position to label to be positioned.

The advantage that the present invention is based on the radio frequency recognition indoor position finding and detection method of received signal intensity is: (1) uses the RFID technology, can realize non-contacting remote read-write; (2) utilize the RSS parameter, be easier to collect relevant information; (3) used neighbor search method NNSS (Nearest Neighbors basedon Signal Strength) based on RSS intensity, the information to collecting that can be simple and effective is handled and is mated, and selects suitable reference label; (4) set up the universality signal space for indoor positioning detects among the present invention, improved the universality of algorithm.

Description of drawings

Fig. 1 is the present invention lays four card reader in indoor environment a layout structure synoptic diagram.

Fig. 2 is the process flow diagram that detection and localization of the present invention is handled.

Fig. 3 is another process flow diagram that detection and localization of the present invention is handled.

Embodiment

The present invention is described in further detail below in conjunction with drawings and Examples.

The location estimation that the present invention treats positioning label is to be implemented on the theoretical foundation of neighbor search, concretism is: for each label to be positioned and reference label, difference definition signal intensity vector, and introduce Euclidean distance (Euclidean distance) and measure, position between reference label and the label to be positioned relation is judged, thereby Unknown Label is positioned.By this method, can obtain several neighbour's labels of label to be positioned, and infer by the position that their known position coordinateses are treated positioning label.The invention provides a kind of efficient 2-d location algorithm, realized according to the location of indoor known location reference label to mobile tag.At the treatment step of position finding and detection method of the present invention referring to flow process shown in Figure 2.

Radio-frequency (RF) identification (RFID) indoor position finding and detection method that the present invention is based on received signal intensity (RSS) comprises following several steps:

The first step: respectively b reference label gathered its received signal intensity level by n card reader earlier

And $\stackrel{\→}{{\mathrm{\θ}}_b}=\{{\mathrm{\θ}}_1,{\mathrm{\θ}}_2,{\mathrm{\θ}}_3{\·\·\·\·\·\·\mathrm{\θ}}_n\};$

θ ₁Represent the received signal intensity level that the 1st card reader gathered b reference label,

θ ₂Represent the received signal intensity level that the 2nd card reader gathered b reference label,

θ ₃Represent the received signal intensity level that the 3rd card reader gathered b reference label,

θ _nRepresent the received signal intensity level that n card reader gathered b reference label.

Respectively a label to be positioned gathered its received signal intensity level by n card reader then And

$\stackrel{\&RightArrow;}{S_a}=\{{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_2,{\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_3\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;S_n\};$

S ₁Represent the received signal intensity level that the 1st card reader gathered a label to be positioned,

S ₂Represent the received signal intensity level that the 2nd card reader gathered a label to be positioned,

S ₃Represent the received signal intensity level that the 3rd card reader gathered a label to be positioned,

S _nRepresent the received signal intensity level that n card reader gathered a label to be positioned.

Then with reference label intensity Label intensity to be positioned

Send data acquisition unit to;

Second step: the reference label intensity of data acquisition unit to receiving Label intensity to be positioned

According to euclidean distance metric $E_{a,b}={\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{({\mathrm{\&theta;}}_i-S_i)}^2\right)}^{\frac{1}{2}}$ Obtain the Euclidean distance vector of a label to be positioned;

I represents i card reader, θ _iRepresent the reference label received signal intensity level read on i the card reader, S _iRepresent the label received signal intensity level to be positioned read on i the card reader;

The 3rd step: repeat the euclidean distance metric E that second step obtained all m reference label and a label to be positioned _{A, j}, and j ∈ (1, m), j represents j reference label;

The 4th step: to the 1st reference label of the 3rd step acquisition and the distance metric E of a label to be positioned _{A, 1}, the 2nd reference label and a label to be positioned distance metric E _{A, 2}, the 3rd reference label and a label to be positioned distance metric E _{A, 3}The distance metric E of m reference label and a label to be positioned _{A, m}Sort from small to large;

The 5th step: select minimum pairing four reference label of four distance metrics in the 4th step; Described four reference label are apart from a four nearest neighbour's labels of label to be positioned;

The 6th step:, calculate the estimated position of a label to be positioned according to these four position coordinateses that neighbour's label is known.When certain reference label hour thinks that then the individual label to be positioned of this reference label and a is near more more at a distance of the distance metric of a label to be positioned.

At all the other labels to be positioned as shown in Figure 1, repeat the estimated position that above-mentioned steps can obtain each label to be positioned.

In order to reduce the error of detection and localization of the present invention, assurance is treated the position of positioning label and is accurately located, also can be after the above-mentioned first step finishes, carry out the processing of universality signal space model before the beginning of second step, promptly radio-frequency (RF) identification (RFID) indoor position finding and detection method based on received signal intensity (RSS) comprises following several steps:

The first step: respectively b reference label gathered its received signal intensity level by n card reader earlier

And $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_b}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3{\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\mathrm{\&theta;}}_n\};$

Respectively a label to be positioned gathered its received signal intensity level by n card reader then

And

$\stackrel{\&RightArrow;}{S_a}=\{{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_2,{\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_3\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;S_n\};$

Then with reference label intensity

Label intensity to be positioned

Send data acquisition unit to;

Carry out carrying out again for second step after the universality signal space models treated for the quantity of information in the data acquisition unit: the reference label intensity of data acquisition unit to receiving

Label intensity to be positioned

According to euclidean distance metric $E_{a,b}={\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{({\mathrm{\&theta;}}_i-S_i)}^2\right)}^{\frac{1}{2}}$ Obtain the Euclidean distance vector of a label to be positioned;

The 3rd step: repeat the euclidean distance metric E that second step obtained all m reference label and a label to be positioned _{A, j}, and j ∈ (1, m), j represents j reference label;

The 4th step: to the 1st reference label of the 3rd step acquisition and the distance metric E of a label to be positioned _{A, 1}, the 2nd reference label and a label to be positioned distance metric E _{A, 2}, the 3rd reference label and a label to be positioned distance metric E _{A, 3}The distance metric E of m reference label and a label to be positioned _{A, m}Sort from small to large;

The 5th step: select minimum pairing four reference label of four distance metrics in the 4th step; Described four reference label are apart from a four nearest neighbour's labels of label to be positioned;

The 6th step:, calculate the estimated position of a label to be positioned according to these four position coordinateses that neighbour's label is known.When certain reference label hour thinks that then the individual label to be positioned of this reference label and a is near more more at a distance of the distance metric of a label to be positioned.

The structure of universality signal space model has used the method for a kind of estimated signal strength increment Delta rss to come the original signal space is revised, basic thought is exactly as standard label with label to be positioned, the signal space of all reference label in the scene of location is estimated respectively to revise, and then revised signal space is used for follow-up location, promptly for each reference label, in its signal space each is deducted corrected parameter rssm, make the error of bringing by estimated signal strength increment Delta rss reduce to minimum.

Universality signal space model is:

//n: the quantity of card reader in the system

//REFTAGNUM: the quantity that participates in the reference label of location in the system

//rssm: corrected parameter

//TAG_TRACK_RSS: the signal space of label to be positioned

//TAG_REF_RSS (:, i): the signal space of i reference label

//sum (T): to the element summation of signal space vector T

for(i＝1：REFTAGNUM)

rssm＝(sum(TAG_TRACK_RSS)-sum(TAG_REF_RSS(:，i)))/n；

TAG_REF_RSS(:，i)＝TAG_REF_RSS(:，i)+rssm；

End

Be called the universality signal space through the revised signal space of corrected parameter rssm, the signal space distortion that the foundation of universality signal space causes the label differences has dropped to minimum, for the neighbor search process provides unified distance metric computing platform, improved universality, made it can tackle the situation of many label coexistences in the practical application based on the RFID neighbour location algorithm of RSS.

Embodiment 1:Location estimation at 49 reference label and 7 labels to be positioned

Referring to shown in Figure 1, lay four card reader (A card reader, B card reader, C card reader, D card reader) on four angles in indoor environment, around being evenly distributed on, in environment space, be placed with 49 reference label as far as possible with 1m equally spaced, be divided into seven row, every row has seven reference label.Seven labels to be positioned placing are respectively first label A to be positioned 1, second label A to be positioned 2, the 3rd label A to be positioned 3, the 4th label A to be positioned 4, the 5th label A to be positioned 5, the 6th label A to be positioned 6, the 7th label A 7 to be positioned.

Adopt above-mentioned method concrete steps to have for first label A 1 to be positioned being carried out the estimated position:

Earlier respectively 49 reference label are gathered its received signal intensity level by four card reader

$\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_1}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\},$ $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_2}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\},$ $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_3}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\}\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_{49}}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\};$

Respectively first label A 1 to be positioned is gathered its received signal intensity level by four card reader then

$\stackrel{\&RightArrow;}{S_{A1}}=\{{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_2,{\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_3{,S}_4\};$

Then with reference label intensity $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_1}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\},$ $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_2}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\},$ $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_3}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\}\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_{49}}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\},$ Label intensity to be positioned $\stackrel{\&RightArrow;}{{\mathrm{<figure-callout\; id="1"\; label="S\; A"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_A}=\{{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_2,{\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S2007101793195E00011.png"\; state="\{\{state\}\}">S</figure-callout>}}_3{,S}_4\}$ Send data acquisition unit to;

The reference label intensity of data acquisition unit to receiving $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_1}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\},$ $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_2}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\},$ $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_3}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\}\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_{49}}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&theta;}}_4\},$ Label intensity to be positioned $\stackrel{\&RightArrow;}{S_{A1}}=\{S_1,S_2,S_3{,S}_4\}$ According to the distance metric of euclidean distance metric acquisition about the 1st reference label and first label A 1 to be positioned $E_{A1,1}={\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{({\mathrm{\&theta;}}_i-S_i)}^2\right)}^{\frac{1}{2}},$ The distance metric of the 2nd reference label and first label A 1 to be positioned $E_{A1,2}={\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{({\mathrm{\&theta;}}_i-S_i)}^2\right)}^{\frac{1}{2}},$ The distance metric of the 3rd reference label and first label A 1 to be positioned $E_{A1,3}={\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{({\mathrm{\&theta;}}_i-S_i)}^2\right)}^{\frac{1}{2}}\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;$ The distance metric of the 49th reference label and first label A 1 to be positioned

$E_{A1,49}={\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{({\mathrm{\&theta;}}_i-S_i)}^2\right)}^{\frac{1}{2}};$

49 reference label of above-mentioned acquisition and the distance metric of first label A 1 to be positioned are sorted from small to large; And select minimum pairing four reference label of four distance metrics (No. 9 reference label, No. 10 reference label, No. 16 reference label, No. 17 reference label); Described No. 9 reference label, No. 10 reference label, No. 16 reference label, No. 17 reference label are apart from four nearest neighbour's labels of first label A to be positioned 1;

With the B card reader is initial point, A card reader direction is the X-axis positive dirction, C card reader direction is the Y-axis positive dirction, the position coordinates that No. 9 reference label are then arranged is (3,7), the position coordinates of No. 10 reference label is (4,7), the position coordinates of No. 16 reference label is that the position coordinates of (3,6), No. 17 reference label is (4,6).

The estimated position that first label A 1 to be positioned is then arranged is in the scope of determining of No. 9 reference label, No. 10 reference label, No. 16 reference label, No. 17 reference label.At last according to the distance metric E of No. 9 reference label and first label A 1 to be positioned _A1,9, No. 10 reference label and first label A 1 to be positioned distance metric E _A1,10, No. 16 reference label and first label A 1 to be positioned distance metric E _A1,16, No. 17 reference label and first label A 1 to be positioned distance metric E _A1,17Size determine the particular location of first label A 1 to be positioned.

Adopt above-mentioned same procedure to position respectively at second label A to be positioned 2, the 3rd label A to be positioned 3, the 4th label A to be positioned 4, the 5th label A to be positioned 5, the 6th label A to be positioned 6, the 7th label A 7 to be positioned.

Then have: the estimated position of second label A 2 to be positioned is in the scope of determining of No. 11 reference label, No. 12 reference label, No. 18 reference label, No. 19 reference label.Last distance metric E according to No. 11 reference label and second label A 2 to be positioned _A2,11, No. 12 reference label and second label A 2 to be positioned distance metric E _A2,12, No. 18 reference label and second label A 2 to be positioned distance metric E _A2,18, No. 19 reference label and second label A 2 to be positioned distance metric E _A2,19Size determine the particular location of second label A 2 to be positioned.

Then have: the estimated position of the 3rd label A 3 to be positioned is in the scope of determining of No. 15 reference label, No. 16 reference label, No. 22 reference label, No. 23 reference label.Last distance metric E according to No. 15 reference label and the 3rd label A 3 to be positioned _A3,15, No. 16 reference label and the 3rd label A 3 to be positioned distance metric E _A3,16, No. 22 reference label and the 3rd label A 3 to be positioned distance metric E _A3,22, No. 23 reference label and the 3rd label A 3 to be positioned distance metric E _A3,23Size determine the particular location of the 3rd label A 3 to be positioned.

Then have: the estimated position of the 4th label A 4 to be positioned is in the scope of determining of No. 25 reference label, No. 26 reference label, No. 32 reference label, No. 33 reference label.Last distance metric E according to No. 25 reference label and the 4th label A 4 to be positioned _A4,25, No. 26 reference label and the 4th label A 4 to be positioned distance metric E _A4,26, No. 32 reference label and the 4th label A 4 to be positioned distance metric E _A4,33, No. 33 reference label and the 4th label A 4 to be positioned distance metric E _A4,34Size determine the particular location of the 4th label A 4 to be positioned.

Then have: the estimated position of the 5th label A 5 to be positioned is in the scope of determining of No. 30 reference label, No. 31 reference label, No. 37 reference label, No. 38 reference label.Last distance metric E according to No. 30 reference label and the 5th label A 5 to be positioned _A5,30, No. 31 reference label and the 5th label A 5 to be positioned distance metric E _A5,31, No. 37 reference label and the 5th label A 5 to be positioned distance metric E _A5,37, No. 38 reference label and the 5th label A 5 to be positioned distance metric E _A5,38Size determine the particular location of the 5th label A 5 to be positioned.

Then have: the estimated position of the 6th label A 6 to be positioned is in the scope of determining of No. 38 reference label, No. 39 reference label, No. 45 reference label, No. 46 reference label.Last distance metric E according to No. 38 reference label and the 6th label A 6 to be positioned _A6,38, No. 39 reference label and the 6th label A 6 to be positioned distance metric E _A6,39, No. 45 reference label and the 6th label A 6 to be positioned distance metric E _A6,45, No. 46 reference label and the 6th label A 6 to be positioned distance metric E _A6,46Size determine the particular location of the 6th label A 6 to be positioned.

Then have: the estimated position of the 7th label A 7 to be positioned is in the scope of determining of No. 41 reference label, No. 42 reference label, No. 48 reference label, No. 49 reference label.Last distance metric E according to No. 41 reference label and the 7th label A 7 to be positioned _47,41, No. 42 reference label and the 7th label A 7 to be positioned distance metric E _A7,42, No. 48 reference label and the 7th label A 7 to be positioned distance metric E _A7,48, No. 49 reference label and the 7th label A 7 to be positioned distance metric E _A7,49Size determine the particular location of the 7th label A 7 to be positioned.

The RSS parameter that the present invention utilizes, promptly received wireless signal strength during RFID card reader label reading is a messaging parameter relevant with distance, can effectively be applied among the wireless location system.

The present invention can effectively realize indoor electric subtab location, utilize the universality algorithm that proposes in the invention, can effectively suppress the error brought by the label differences, the level when bearing accuracy is brought up to the label indifference can satisfy this field actual demand.This invention can be applied to have good practical reference value in a lot of wireless location systems.

Claims (2)

1. radio frequency recognition indoor position finding and detection method based on received signal intensity is characterized in that comprising following several steps:

The first step: respectively b reference label gathered its received signal intensity level by n card reader earlier And $\stackrel{\&RightArrow;}{{\mathrm{\&theta;}}_b}=\{{\mathrm{\&theta;}}_1,{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3{\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\mathrm{\&theta;}}_n\};$

Respectively a label to be positioned gathered its received signal intensity level by n card reader then

And

$\stackrel{\&RightArrow;}{S_a}=\{S_1,S_2,S_3\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;S_n\};$

Then with reference label intensity

Label intensity to be positioned

Send data acquisition unit to;

Second step: the reference label intensity of data acquisition unit to receiving

Label intensity to be positioned

According to euclidean distance metric $E_{a,b}={\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{({\mathrm{\&theta;}}_i-S_i)}^2\right)}^{\frac{1}{2}}$ Obtain the Euclidean distance vector of a label to be positioned;

I represents i card reader, θ _iRepresent the reference label received signal intensity level read on i the card reader, S _iRepresent the label received signal intensity level to be positioned read on i the card reader;

The 3rd step: repeat the euclidean distance metric E that second step obtained all m reference label and a label to be positioned _{A, j}, and j ∈ (1, m), j represents j reference label;

The 4th step: to the 1st reference label of the 3rd step acquisition and the distance metric E of a label to be positioned _{A, 1}, the 2nd reference label and a label to be positioned distance metric E _{A, 2}, the 3rd reference label and a label to be positioned distance metric E _{A, 3}The distance metric E of m reference label and a label to be positioned _{A, m}Sort from small to large;

The 5th step: select minimum pairing four reference label of four distance metrics in the 4th step; Described four reference label are apart from a four nearest neighbour's labels of label to be positioned;

The 6th step:, calculate the estimated position of a label to be positioned according to these four position coordinateses that neighbour's label is known.

2. the radio frequency recognition indoor position finding and detection method based on received signal intensity according to claim 1 is characterized in that: after the first step finishes, carry out the processing of universality signal space model before the beginning of second step; Described universality signal space model is:

//n: the quantity of card reader in the system

//REFTAGNUM: the quantity that participates in the reference label of location in the system

//rssm: corrected parameter

//TAG_TRACK_RSS: the signal space of label to be positioned

//TAG_REF_RSS (:, i): the signal space of i reference label

//sum (T): to the element summation of signal space vector T

for(i＝1：REFTAGNUM)

rssm＝(sum(TAG_TRACK_RSS)-sum(TAG_REF_RSS(:，i)))/n；

TAG_REF_RSS(:，i)＝TAG_REF_RSS(:，i)+rssm；

End。

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