CN101776746A - Device and method for positioning angle of signal arrival and measuring wave-path difference of signal - Google Patents

Abstract

The invention relates to a positioning method in short range or indoor space and a system thereof, more particularly to a device and a method for positioning angle of signal arrival and measuring wave-path difference of signal. In order to provide the positioning method and the system thereof capable of offsetting the variation generated by an inference signal and greatly enhancing positioning precision, the technical proposal adopted in the invention is that: the device comprises an antenna for transmitting instruction radio frequency signals and receiving the radio frequency signals transmitted by responders; a transmitter for transmitting a responder communication instruction; a receiver for receiving the radio frequency signals transmitted by the responders and processing the signals; an AD converter for implementing uniform cycle sampling on baseband sine wave output by the receiver and converting voltage values of sampling into numerical codes with certain precision and sending the numerical codes to a computer for being processed; and a terminal processing computer for inputting pre-coded wave-path difference measurement algorithmic routine and coordinates positioning algorithmic routine, and outputting the coordinates of the responders through a display. The device and the method are mainly applied to the positioning in short range or indoor space.

Description

Signal arrives angle orientation and signal wave path difference measurement mechanism and method

Technical field

This relates to closely or the localization method and the system of the interior space, use radio-frequency (RF) identification (RFID, Radio FrequencyIDentification) technology is finished the location to object, relate to a kind of RFID localization method and system that can improve bearing accuracy, specifically relate to signal and arrive angle orientation and signal wave path difference measurement mechanism and method.

Background technology

The develop rapidly of mobile computing technology and wireless local area network technology has promoted advancing by leaps and bounds of mobile positioning technique.For outdoor positioning system, the application of foremost global position system GPS is seen everywhere, but for being applied to closely or positioning system in the interior space, gps system has tangible limitation, carry out location in the indoor enclosure space and use radio-frequency (RF) identification (RFID) technology be born in automatic identification field, with other location technology incomparable advantage such as its noncontact, non line of sight, bearing accuracy height and cost are low, obtained more and more people's concern.

In the whole bag of tricks that applying RFID technology positions, it is new the proposition that signal arrives angle localization method (AOA), can improve a kind of Important Thought of bearing accuracy.Normally based on several groups of readers (minimum is two groups),, in conjunction with the distance between two groups of readers, finish location then to transponder by calculating the angle of transponder reflected signal and reader.Arrive the angle localization method based on AOA (angle ofarrival) signal and have low cost, easily realize, advantage such as antijamming capability is strong, and principle is simple.The used transponder of RFID localization method that arrives angle based on signal both can be an active balise, also can be passive balise.

The RFID positioning system that arrives the angle localization method based on AOA (angle of arrival) signal mainly adopts following working method: reader sends radiofrequency signal, this signal arrives transponder, and transponder is finished behind the signal processing tasks again with radiofrequency signal reflected back reader.As shown in Figure 1, suppose the distant place of label at aerial array, the distance between label and the antenna＞＞spacing of aerial array unit, then the signal of label arrival antenna place can regard plane wave as, if the spacing between the known antenna array elements, the array group distance, according to the trigonometric function algorithm, can get $\mathrm{\α}=\arccos \left(\frac{\mathrm{l\Δ\θ}}{2\mathrm{\πd}}\right),$ Wherein α is the angle of arriving signal and antenna, and d is the distance of adjacent two antennas, and Δ θ is the phase differential of the signal that receives, and l is the wavelength that signal is modulated to the sine wave of reader output behind the low frequency.Therefore require arriving signal angle α, need know that adjacent two antennas receive the phase difference θ of signal.Behind the angle of trying to achieve return signal and reader, utilize the trigonometric function algorithm to obtain corresponding coordinate formula, just can obtain the coordinate figure of label then in the space.We call this localization method: arrive the passive RFID location that angle signal arrives Angle Method based on signal, the data computation of this location can be finished by relevant location algorithm program.It need not change and is used to read and write the conventional reader of identification and the hardware configuration of transponder, only needs external analog and digital signal converter, by calculating the angle of transponder reflected signal and reader, finally finishes the location to transponder by the located in connection algorithm routine.

Existing based in the signal arrival reader localization method, utilize the decay of signal to come the position of definite response device, in reader and transponder distance location occasion far away slightly, the intensity level of the received signal of using during calculations for signal attenuation has bigger distortion, thereby has a strong impact on bearing accuracy.

Summary of the invention

For overcoming the deficiencies in the prior art, the object of the present invention is to provide a kind of signal to arrive angle orientation and signal wave path difference measurement mechanism and method, can balance out the variation that produces owing to undesired signal, and improve locating accuracy greatly.For achieving the above object, the technical solution used in the present invention is that a kind of signal arrives angle orientation and signal wave path difference measuring method, comprising:

(1) make reader send radiofrequency signal through transmitting antenna;

(2) make transponder to be positioned utilize transponder antenna to receive the radiofrequency signal that reader sends, signal Processing finishes and still adopts the radiofrequency signal after modulating to return reader;

(3) make reader carry out modulation, the low-frequency sine signal after the output demodulation to high-frequency signal;

(4) the sine wave signal uniform sampling that AD converter is sent out reader, the voltage transitions that sampling is obtained is a digital quantity, digital quantity after the conversion is sent to computing machine, by the digital quantity of computing machine according to characterization signal, obtain the wave path-difference of the sine wave that adjacent two antennas receive, in conjunction with the angle of trigonometric function algorithm computation transponder reflected signal and reader, again according to the distance of antenna, obtain the coordinate figure mathematic(al) representation of transponder, finish location transponder.

The sine wave signal uniform sampling that AD converter is sent out reader is that to make two AD converter that are connected with adjacent two readers be under the control of same sampling clock adjacent two antennas to be received that signal carries out the sampling of 4 frequencys multiplication, obtains two antennas and receives and arrive signals sampling value I in the signal earlier ₁=sin λ, $Q_1=\sin (\mathrm{\&lambda;}+\frac{T}{4}).$ Obtain the sampled value I of back arriving signal ₂=sin μ, ${\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="H201010031307XE00021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2=\sin (\mathrm{\&mu;}+\frac{T}{4}),$ Obtain the resultant vector angle of two paths of signals respectively ${\mathrm{\&theta;}}_1=\arctan \frac{Q_1}{I_1},$ ${\mathrm{\&theta;}}_2=\arctan \frac{Q_2}{I_2},$ And then obtain adjacent two antennas receive the phase difference θ of signal=| θ ₁-θ ₂|, when signal wavelength is l, the wave path-difference of adjacent signals is showed with phase difference θ, both wave path-difference $d*\cos \mathrm{\&alpha;}=l*\frac{\mathrm{\&Delta;\&theta;}}{2\mathrm{\&pi;}},$ Can obtain $\mathrm{\&alpha;}=\arccos \left(\frac{\mathrm{l\&Delta;\&theta;}}{2\mathrm{\&pi;d}}\right),$ Be connected with reader four every adjacent two of antennas that are used to receive and dispatch radiofrequency signal are formed an aerial array totally two aerial arrays, the coordinate figure of supposing one of them aerial array is (0,0), the coordinate figure of another aerial array is (0, h), two reference label record target labels signal incident angle and are respectively α and β, and then according to trigonometric function knowledge, the position of target response device can obtain by following formula: $x=\frac{h}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}},$ $y=\frac{h\cot \mathrm{\&beta;}}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}}.$

A kind of signal arrives angle orientation and signal wave path difference measurement mechanism, comprise: at least four are used for antenna that reader that transponder reads identification, be connected with reader four be used to receive and dispatch radiofrequency signal, four external high-precision A converters, passive balise and computing machine to be positioned, described single reader and AD converter comprise:

An antenna is used for the firing order radiofrequency signal and receives the radiofrequency signal that is sent by each transponder device.

A transmitter is used for the circuit module of transponder communication instruction.

A receiver is used for receiving the radiofrequency signal of transponder emission, and carries out the circuit module of signal Processing.

An AD converter, its effect are that the base band sine wave that receiver is exported is carried out the uniform period sampling, and the numerical code that the magnitude of voltage of sampling is converted to certain precision is delivered to computer programs process.

A terminal processes computing machine, wave path-difference Measurement Algorithm program and coordinate setting algorithm routine that input is finished in advance, and by display output transponder coordinate.

Two AD converter that are connected with adjacent two readers receive that to adjacent two antennas signal carries out the sampling of 4 frequencys multiplication under same sampling clock control, obtain two antennas and receive that elder generation arrives signals sampling value I in the signal ₁=sin λ, $Q_1=\sin (\mathrm{\&lambda;}+\frac{T}{4}).$ Obtain the sampled value I of back arriving signal ₂=sin μ, ${\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="H201010031307XE00021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2=\sin (\mathrm{\&mu;}+\frac{T}{4}),$ Obtain the resultant vector angle of two paths of signals respectively ${\mathrm{\&theta;}}_1=\arctan \frac{Q_1}{I_1},$ ${\mathrm{\&theta;}}_2=\arctan \frac{Q_2}{I_2},$ And then obtain adjacent two antennas receive the phase difference θ of signal=| θ ₁-θ ₂|, when signal wavelength is l, the wave path-difference of adjacent signals is showed with phase difference θ, both wave path-difference $d*\cos \mathrm{\&alpha;}=l*\frac{\mathrm{\&Delta;\&theta;}}{2\mathrm{\&pi;}},$ Can obtain $\mathrm{\&alpha;}=\arccos \left(\frac{\mathrm{l\&Delta;\&theta;}}{2\mathrm{\&pi;d}}\right),$ Be connected with reader four every adjacent two of antennas that are used to receive and dispatch radiofrequency signal are formed an aerial array totally two aerial arrays, the coordinate figure of supposing one of them aerial array is (0,0), the coordinate figure of another aerial array is (0, h), two reference label record target labels signal incident angle and are respectively α and β, and then according to trigonometric function knowledge, the position of target response device can obtain by following formula: $x=\frac{h}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}},$ $y=\frac{h\cot \mathrm{\&beta;}}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}}.$

The present invention has following outstanding advantage: the signal phase difference that the inventive method utilizes adjacent antenna to receive is located, with the ratio of the external ADC sampled value of reader relation is arranged, and irrelevant with the absolute strength of signal, if signal is interfered, then the sampled value of external ADC will become tI ₁And tQ ₁, wherein t is the impaired coefficient value of signal, when calculating the phase differential of adjacent signals, uses mathematical formulae ${\mathrm{\&theta;}}_1=\arctan \frac{Q_1}{I_1},$ Therefore can balance out because the variation that undesired signal produces still can keep high orientation precision after therefore being interfered.

Description of drawings

Fig. 1 is based on the RFID positioning system schematic diagram of AOA (signal arrival angle) method.

Fig. 2 is the schematic diagram that calculates the phase differential of adjacent antenna received signal.

Fig. 3 is based on AOA (signal arrival angle) method and determines that target response device position coordinate puts synoptic diagram.

Fig. 4 is based on the system chart of AOA (signal arrival angle) method location.

Embodiment

Be the positioning error that the interference that overcomes or central object fainter owing to received signal brings, the present invention proposes a kind of RFID localization method that arrives angle (signal arrival angle) transponder based on signal.Technical scheme of the present invention is as follows:

A kind of RFID localization method that can improve bearing accuracy utilizes at least four readers, adopts the locator meams location based on AOA (signal arrival angle) transponder, comprises the following steps:

(1) radiofrequency signal sent through transmitting antenna of reader;

(2) transponder to be positioned utilizes antenna to receive the radiofrequency signal that reader sends, and signal Processing finishes and still adopts the radiofrequency signal after modulating to return reader;

(3) reader carries out modulation to high-frequency signal, the low-frequency sine signal after the output demodulation;

(4) AD converter sine wave signal uniform sampling that reader is sent out, the voltage transitions that sampling is obtained is a digital quantity, digital quantity after the conversion is sent to computing machine, by the digital quantity of computing machine according to characterization signal, obtain the wave path-difference (phase place with ripple is represented) of the sine wave that adjacent two antennas receive, angle in conjunction with trigonometric function algorithm computation transponder reflected signal and reader, again according to the distance of antenna, obtain the coordinate figure mathematic(al) representation of transponder, finish location transponder.

The present invention provides a kind of positioning system that realizes said method simultaneously, comprise: at least four are used for antenna that reader that transponder reads identification, be connected with reader four be used to receive and dispatch radiofrequency signal, four external high-precision A converters, passive balise and computing machine to be positioned, it is characterized in that, described single reader and AD converter comprise:

An antenna is used for the firing order radiofrequency signal and receives the radiofrequency signal that is sent by each transponder device.

A transmitter is used for the circuit module of transponder communication instruction.

A receiver is used for receiving the radiofrequency signal of transponder emission, and carries out the circuit module of signal Processing.

An AD converter, its effect are that the base band sine wave that receiver is exported is carried out the uniform period sampling, and the numerical code that the magnitude of voltage of sampling is converted to certain precision is delivered to computer programs process.

A terminal processes computing machine, wave path-difference Measurement Algorithm program and coordinate setting algorithm routine that input is finished in advance, and by display output transponder coordinate.

Described reader carries out modulation to the high-frequency signal that transponder returns, the low-frequency sine signal after the output demodulation; The sine wave signal uniform sampling that the external AD converter of each reader sends out reader, sampled voltage is converted to digital quantity, digital quantity after the conversion is sent to computing machine, by the digital quantity of computing machine according to characterization signal, obtain the wave path-difference (phase place with ripple is represented) of the sine wave that adjacent two antennas receive, angle in conjunction with trigonometric function algorithm computation transponder reflected signal and reader, again according to the distance between the antenna, obtain the coordinate figure mathematic(al) representation of transponder, finish location transponder.

As shown in Figure 2, calculate adjacent two antennas and receive that the wave path-difference of signal is that the phase differential process is as follows, the later base band low frequency signal of adjacent two readers output modulation carries out the sampling of 4 frequencys multiplication with the ADC under the same sampling clock control to two paths of signals respectively, obtains arriving earlier signals sampling value I ₁=sin λ, $Q_1=\sin (\mathrm{\&lambda;}+\frac{T}{4}).$ Obtain the sampled value I of back arriving signal ₂=sin μ, ${\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="H201010031307XE00021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2=\sin (\mathrm{\&mu;}+\frac{T}{4}).$ Obtain the resultant vector angle of two paths of signals respectively ${\mathrm{\&theta;}}_1=\arctan \frac{Q_1}{I_1},$ ${\mathrm{\&theta;}}_2=\arctan \frac{Q_2}{I_2}.$ And then obtain adjacent two antennas receive the phase difference θ of signal=| θ ₁-θ ₂|.In conjunction with the accompanying drawings 1, when signal wavelength is l, the wave path-difference of adjacent signals is showed with phase difference θ, both wave path-difference $d*\cos \mathrm{\&alpha;}=l*\frac{\mathrm{\&Delta;\&theta;}}{2\mathrm{\&pi;}},$ Can obtain $\mathrm{\&alpha;}=\arccos \left(\frac{\mathrm{l\&Delta;\&theta;}}{2\mathrm{\&pi;d}}\right),$ As shown in Figure 3, if want to determine the two-dimensional coordinate position of label, need two aerial array groups at least.The coordinate figure of supposing aerial array 2 is (0,0), and the coordinate figure of aerial array 1 is that (0, h), two reference label record target labels signal incident angle and are respectively α and β.Then according to trigonometric function knowledge, the position of target response device can obtain by following formula: $x=\frac{h}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}},$ $y=\frac{h\cot \mathrm{\&beta;}}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}}.$

Further specify the present invention below in conjunction with drawings and Examples.

The workflow that the RFID based on AOA (signal arrival angle) method that the present invention proposes locatees is: reader sends signal by antenna, receive by transponder antenna, transponder is modulated to radio frequency with return signal and returns reader through antenna transmission then, reader carries out modulation to radiofrequency signal, the low frequency signal after the output demodulation; External AD converter is converted to digital quantity to the sine wave signal uniform sampling that reader sends out with sampled voltage, just can calculate the angle that arrives reader signal and reader thus, and then utilize the trigonometric function algorithm to draw the coordinate of transponder.Compare with the localization method that arrives reader based on signal, ratio after the signal that this method utilizes adjacent two readers to receive is sampled by ADC calculates, irrelevant with the absolute strength of signal, therefore can reduce the reflection interference in the positioning system greatly, improve bearing accuracy.Below in conjunction with each accompanying drawing concrete analysis.

As shown in Figure 1, require arriving signal and reader angle α, need know that adjacent two antennas receive the wave path-difference d of signal, the form of wave path-difference with phase differential θ showed, both $d*\cos \mathrm{\&alpha;}=l*\frac{\mathrm{\&Delta;\&theta;}}{2\mathrm{\&pi;}},$ Wherein d is the distance of adjacent two antennas, and Δ θ is the phase differential of the signal that receives, and l is the wavelength that signal is modulated to the sine wave of reader output behind the low frequency.Thereby problem is converted into the problem of the phase differential of how to try to achieve two paths of signals.As shown in Figure 2, calculate adjacent two antennas and receive the phase differential of signal, two sine waves are the later base band low frequency signal of adjacent two readers output modulation, with the ADC under the same sampling clock control two paths of signals are carried out the sampling of 4 frequencys multiplication respectively, obtain arriving earlier signals sampling value I ₁=sin λ, $Q_1=\sin (\mathrm{\&lambda;}+\frac{T}{4}).$ Obtain the sampled value I of back arriving signal ₂=sin μ, ${\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="H201010031307XE00021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2=\sin (\mathrm{\&mu;}+\frac{T}{4}).$ Obtain the resultant vector angle of two paths of signals respectively ${\mathrm{\&theta;}}_1=\arctan \frac{Q_1}{I_1},$ ${\mathrm{\&theta;}}_2=\arctan \frac{Q_2}{I_2}.$ And then obtain adjacent two antennas receive the phase difference θ of signal=| θ ₁-θ ₂|.If signal is interfered, then the sampled value of external ADC will become tI ₁And tQ ₁, wherein t is the impaired coefficient value of signal, when still calculating the phase differential of adjacent signals, uses mathematical formulae ${\mathrm{\&theta;}}_1=\arctan \frac{Q_1}{I_1},$ Therefore can balance out because the variation that undesired signal produces, the result that calculated signals when not being interfered goes out much at one, because when phase differential is constant, the transponder reflected signal of being obtained by phase differential and the angle of reader can not change yet, therefore the transponder coordinate that obtains is irrelevant with interference, will improve the transponder locating accuracy greatly.

As shown in Figure 3, if want to determine the two-dimensional coordinate position of label, need two aerial array groups at least.The coordinate figure of supposing aerial array 2 is (0,0), and the coordinate figure of aerial array 1 is that (0, h), two reference label record target labels signal incident angle and are respectively α and β.Then the position of target labels can obtain by following formula: $x=\frac{h}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}},$ $y=\frac{h\cot \mathrm{\&beta;}}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}}.$ I wherein ₁, I ₂, Q ₂, Q ₁Analogue value size obtain by external ADC sampling, be converted to the binary digital code of certain precision then, utilize serial ports or USB interface communication or additive method to be admitted in the computing machine.

As shown in Figure 4,, these data are handled, finally calculated the particular location of transponder in the space and show by the algorithm routine that the utilization of terminal processes computing machine writes in advance according to the aforementioned calculation formula.

The reader of using is in the methods of the invention compared with the reader that is used for read-write identification of routine, hardware circuit need not to change, only need at the external analog and digital signal converter of each reader output signal port, according to the base band wave frequency, adopting 4 times of sampling clock controlled frequencies to the baseband wave frequency that baseband wave is sampled, is that the data signal of certain precision is sent into the computerized algorithm routine processes with the analog signal conversion after the sampling. In this localization method related positioning system structure as shown in Figure 4, its main circuit forms structure and comprises: the external AD signal adapter of (1) reader emitter (2) reader receiver (3) (4) is finished computer (5) the end coordinates display that wave path-difference is calculated and the elements of a fix calculate.

Claims (4)

1. a signal arrives angle orientation and signal wave path difference measuring method, it is characterized in that, comprising:

(1) make reader send radiofrequency signal through transmitting antenna;

(2) make transponder to be positioned utilize transponder antenna to receive the radiofrequency signal that reader sends, signal Processing finishes and still adopts the radiofrequency signal after modulating to return reader;

(3) make reader carry out modulation, the low-frequency sine signal after the output demodulation to high-frequency signal;

(4) the sine wave signal uniform sampling that AD converter is sent out reader, the voltage transitions that sampling is obtained is a digital quantity, digital quantity after the conversion is sent to computing machine, by the digital quantity of computing machine according to characterization signal, obtain the wave path-difference of the sine wave that adjacent two antennas receive, in conjunction with the angle of trigonometric function algorithm computation transponder reflected signal and reader, again according to the distance of antenna, obtain the coordinate figure mathematic(al) representation of transponder, finish location transponder.

2. a kind of signal according to claim 1 arrives angle orientation and signal wave path difference measuring method, it is characterized in that, the sine wave signal uniform sampling that AD converter is sent out reader is to make two AD converter that are connected with adjacent two readers receive that to adjacent two antennas signal carries out the sampling of 4 frequencys multiplication under same sampling clock control, obtains two antennas and receives that elder generation arrives signals sampling value I in the signal ₁=sin λ, $Q_1=\sin (\mathrm{\&lambda;}+\frac{T}{4}).$ Obtain the sampled value I of back arriving signal ₂=sin μ, $Q_2=\sin (\mathrm{\&mu;}+\frac{T}{4}),$ Obtain the resultant vector angle of two paths of signals respectively ${\mathrm{\&theta;}}_1=\arctan \frac{Q_1}{I_1},$ ${\mathrm{\&theta;}}_2=\arctan \frac{Q_2}{I_2},$ And then obtain adjacent two antennas receive the phase difference θ of signal=| θ ₁-θ ₂|, when signal wavelength is l, the wave path-difference of adjacent signals is showed with phase difference θ, both wave path-difference $d*\cos \mathrm{\&alpha;}=l*\frac{\mathrm{\&Delta;\&theta;}}{2\mathrm{\&pi;}},$ Can obtain $\mathrm{\&alpha;}=\arccos \left(\frac{\mathrm{l\&Delta;\&theta;}}{2\mathrm{\&pi;d}}\right),$ Be connected with reader four every adjacent two of antennas that are used to receive and dispatch radiofrequency signal are formed an aerial array totally two aerial arrays, the coordinate figure of supposing one of them aerial array is (0,0), the coordinate figure of another aerial array is (0, h), two reference label record target labels signal incident angle and are respectively α and β, and then according to trigonometric function knowledge, the position of target response device can obtain by following formula: $x=\frac{h}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}},$ $y=\frac{h\cot \mathrm{\&beta;}}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}}.$

3. a signal arrives angle orientation and signal wave path difference measurement mechanism, it is characterized in that, comprise: at least four are used for antenna that reader that transponder reads identification, be connected with reader four be used to receive and dispatch radiofrequency signal, four external high-precision A converters, passive balise and computing machine to be positioned, described single reader and AD converter comprise:

An antenna is used for the firing order radiofrequency signal and receives the radiofrequency signal that is sent by each transponder device.

A transmitter is used for the circuit module of transponder communication instruction.

A receiver is used for receiving the radiofrequency signal of transponder emission, and carries out the circuit module of signal Processing.

An AD converter, its effect are that the base band sine wave that receiver is exported is carried out the uniform period sampling, and the numerical code that the magnitude of voltage of sampling is converted to certain precision is delivered to computer programs process.

A terminal processes computing machine, wave path-difference Measurement Algorithm program and coordinate setting algorithm routine that input is finished in advance, and by display output transponder coordinate.

4. a kind of signal according to claim 3 arrives angle orientation and signal wave path difference measurement mechanism, it is characterized in that, two AD converter that are connected with adjacent two readers are under same sampling clock control adjacent two antennas to be received that signal carries out the sampling of 4 frequencys multiplication, obtain two antennas and receive that elder generation arrives signals sampling value I in the signal ₁=sin λ, $Q_1=\sin (\mathrm{\&lambda;}+\frac{T}{4}).$ Obtain the sampled value I of back arriving signal ₂=sin μ, $Q_2=\sin (\mathrm{\&mu;}+\frac{T}{4}),$ Obtain the resultant vector angle of two paths of signals respectively ${\mathrm{\&theta;}}_1=\arctan \frac{Q_1}{I_1},$ ${\mathrm{\&theta;}}_2=\arctan \frac{Q_2}{I_2},$ And then obtain adjacent two antennas receive the phase difference θ of signal=| θ ₁-θ ₂|, when signal wavelength is l, the wave path-difference of adjacent signals is showed with phase difference θ, both wave path-difference $d*\cos \mathrm{\&alpha;}=l*\frac{\mathrm{\&Delta;\&theta;}}{2\mathrm{\&pi;}},$ Can obtain $\mathrm{\&alpha;}=\arccos \left(\frac{\mathrm{l\&Delta;\&theta;}}{2\mathrm{\&pi;d}}\right),$ Be connected with reader four every adjacent two of antennas that are used to receive and dispatch radiofrequency signal are formed an aerial array totally two aerial arrays, the coordinate figure of supposing one of them aerial array is (0,0), the coordinate figure of another aerial array is (0, h), two reference label record target labels signal incident angle and are respectively α and β, and then according to trigonometric function knowledge, the position of target response device can obtain by following formula: $x=\frac{h}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}},$ $y=\frac{h\cot \mathrm{\&beta;}}{\cot \mathrm{\&alpha;}+\cot \mathrm{\&beta;}}.$

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