A short baseline positioning method and system for TDOA with precise synchronization of clock and trigger signal.

Abstract

This invention discloses a short baseline positioning method and system for TDOA with precise synchronization of clock and trigger signals, comprising N base stations, N cable bundles, a central station, and a computer terminal, where N≥3; including: the computer terminal acquiring the coordinate positions of the N base stations, acquiring the coordinate position and center frequency of the calibration source, and sending synchronization commands for the clock and trigger signals; the central station receiving the synchronization commands and generating N trigger signals and N clock signals, which are then transmitted to the N base stations respectively; the computer terminal setting parameters and sending positioning commands to each base station, each base station synchronously acquiring IQ data from the radiation source and recording timestamps, and uploading them as data packets; the computer terminal receiving the data packets and performing data unpacking, IQ data processing, time delay estimation, clock calibration, and positioning calculation, and outputting the positioning result; based on engineering hardware and algorithms, the synchronization signal error of each TDOA base station is less than 1 nanosecond, achieving precise positioning of short baseline TDOA, with convenient base station deployment and high positioning accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wireless positioning technology, and more particularly to a TDOA short baseline positioning method and system with accurate synchronization of clock and trigger signal. BACKGROUND

[0002] Accurate positioning of a wireless signal radiation source is an important research direction of wireless signal processing. With the development of wireless communication equipment and information technology, the application range of accurate radiation source positioning technology is increasingly wide. In particular, in the fields of rescue, transportation, logistics, and black radio search, the demand for and role of high-precision radiation source positioning are increasing day by day.

[0003] Passive positioning technology of non-cooperative radiation sources does not need to radiate electromagnetic wave signals outwardly, and does not need prior information of the radiation source signals. It only extracts relevant characteristic parameters from the received radiation source signals to calculate the position of the radiation source, and has the advantages of good concealment, small device size, low cost, high positioning accuracy, and simple application scenarios. Common passive positioning methods include Time Difference of Arrival (TDOA), Angle of Arrival (AOA), Received Signal Strength (RSS), and Frequency Difference of Arrival (FDOA), each of which has its own advantages and disadvantages. Among them, TDOA calculates the position of the radiation source according to the time difference of the same signal reaching different base station receiving antennas, has the highest positioning accuracy, three base stations achieve two-dimensional positioning, and four base stations achieve three-dimensional positioning. The requirements for base station equipment are relatively high, and the base station layout, base station position accuracy, synchronization clock accuracy, and synchronization trigger signal accuracy will all affect the positioning accuracy. The core problem of TDOA is to estimate the time delay difference between different base stations. The time domain correlation method (such as cross-correlation method, generalized cross-correlation method, and matched filter) is generally used. Among them, the clock signal affects the synchronization of the sampling frequency of each base station, and the trigger signal affects the synchronization of the start and end time of sampling. The two factors directly affect the estimation accuracy of the time delay difference, and thus the positioning accuracy.

[0004] At present, the baseline length (distance between base stations) of the existing TDOA positioning method is usually km level, i.e. long baseline, which is used for positioning of radiation sources in a larger range. The clock and trigger synchronization signals of each station generally use the 1PPS trigger signal and 10M clock signal output by the GPS / Beidou receiver. The data is transmitted between base stations by wireless or wired means, and then the time delay estimation and TDOA positioning solution are completed.

[0005] However, the above method has the following problems: ① There is a synchronization difference between different GPS / Beidou receivers and satellite clocks, and the output trigger signal and clock signal have a maximum error of 1ms, and the equivalent distance is 300m, so the TDOA base station can only use a long baseline scheme to reduce the influence of clock error on the positioning result; ② The long baseline method has a large interval between base stations, and the layout cost is large, and is mainly applied to large-range long-distance radiation source positioning, and cannot be applied to short-distance small-range (<1km distance) radiation source positioning; ③ The long baseline method reduces the time delay error through an algorithm, but the positioning error is only hundreds of meters at most, and cannot realize accurate positioning of short-distance radiation sources.

[0006] Therefore, how to provide a TDOA short baseline positioning method and system with accurate synchronization of clock and trigger signal is a problem that those skilled in the art need to solve. SUMMARY

[0007] Therefore, the present application provides a TDOA short baseline positioning method and system with accurate synchronization of clock and trigger signal, which realizes accurate positioning of radiation sources in a small range within 2km, and has convenient base station layout and high positioning accuracy.

[0008] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0009] A TDOA short baseline positioning method with accurate synchronization of clock and trigger signal, comprising the following steps:

[0010] S1. Obtain the coordinate positions of N base stations, obtain the coordinate position and center frequency of the calibration source, and send a synchronization instruction of the clock and trigger signal, N≥3;

[0011] S2. Receive the synchronization instruction and generate N-way trigger signals and N-way clock signals, and transmit them to the N base stations respectively;

[0012] S3. Set parameters and send a positioning instruction to each base station, each base station synchronously collects IQ data of the radiation source and records a time stamp, and packs the IQ data and the time stamp into a data packet and uploads it;

[0013] S4. Receive the data packet and perform data unpacking, IQ data processing, time delay estimation, clock calibration and positioning calculation, and output the positioning result.

[0014] Preferably, the parameters include the center frequency of the target radiation source, the sampling frequency, the sampling time length and the average number.

[0015] Preferably, the specific content of IQ data processing in S4 includes obtaining time delay estimation data through data standardization, interpolation and filtering.

[0016] Preferably, the specific content of time delay estimation in S4 includes:

[0017] x i (n) = s(n) + v i (n)

[0018] x j (n) = αs(n - E t ) + v j (n)

[0019] where x i (n) and x j (n) are the time delay estimation data of base station i and base station j, respectively, n is the time stamp of the record, s(n) is the received radiation source signal, E t is the theoretical time delay difference between base stations, a is the attenuation factor, v i (n) and v j (n) are the noises received by base station i and base station j;

[0020] The received signals of base station i and base station j satisfy the cross-correlation function R 12 (τ):

[0021]

[0022] where τ is the estimated time delay difference, ψ(f) is the generalized cross-correlation function, is the cross power spectral density function of the two signals;

[0023] ψ(f) = H(f)H * (f)

[0024] H(f) is the weighting function;

[0025] When τ = E t , there is a maximum value R 12 (τ), and τ is the estimated value of the time delay difference, i.e.

[0026]

[0027] Preferably, the specific content of the clock calibration in S4 comprises:

[0028] According to the coordinate position of the calibration source, calculate the theoretical value E ct of the time delay difference of the calibration source, and calculate the estimated value of the time delay difference of the calibration source. Compare the estimated value of the time delay difference of the calibration source with the theoretical value E ct to obtain the system error of the time delay estimation. Then the accurate estimated value of the time delay difference of the target radiation source is where is the calculated estimated value of the time delay difference of the target radiation source.

[0029] Preferably, the specific content of the positioning solution in S4 includes:

[0030]

[0031] wherein the coordinates of the radiation source are (x, y), the coordinates of the base station i are (X i ,Y i ), and R i is the distance from the i-th base station to the radiation source, wherein i = 1, 2,..., N, and N is the number of base stations;

[0032] E ij = E i -E j

[0033] R ij = cE ij

[0034] E i and E j are the times at which the signal reaches the base stations i and j, respectively, E ij is the theoretical value of the time delay difference between the base stations i and j, R ij is the theoretical value of the distance difference between the base stations i and j, and c is the speed of wave propagation;

[0035] f i (x, y) is the distance difference between the i-th base station and the base station 1 to the radiation source:

[0036]

[0037] the distance difference between the i-th base station and the base station 1 to the radiation source is the estimated distance difference actually measured, and ε i1 is the estimation error;

[0038] Taylor series expansion of f i (x, y) at (x0, y0) and keeping only the first two terms gives:

[0039]

[0040]

[0041] wherein (x0, y0) is an initial value, x = x0+ δ x , y = y0+ δ y , and f i，0 is the function value of f i (x, y) at (x0, y0), and the above equation is written in matrix form as:

[0042] Aδ = R + e

[0043]

[0044]

[0045]

[0046]

[0047] Solving the above equation using the weighted least squares method, we obtain the solution as follows:

[0048] δ=[A T Q -1 A] -1 A T Q -1 R

[0049] Where Q is the TDOA covariance matrix;

[0050] Let x1 = x0 + δ x y1=y0+δ y Repeat the above process until δ x and δ y Small enough and satisfying a pre-set threshold ε, such that At this point, the radiation source location (x) obtained after k iterations is... k ,y k This is the estimated location.

[0051] A TDOA short baseline positioning system with precise synchronization of clock and trigger signal includes N base stations, N cable bundles, a central station and a computer terminal, where N≥3;

[0052] Each of the base stations includes an antenna and a sensing module, each of the cable bundles includes a trigger signal cable, a clock cable and a data transmission line, and the central station includes a clock and trigger signal source, a signal buffer splitter and a data router;

[0053] The computer terminal is used to obtain the coordinate positions of N base stations, obtain the coordinate position and center frequency of the calibration source, and send synchronization instructions for clock and trigger signals, where N≥3. It is also used to set parameters and send positioning instructions to the central station through the data router. It is also used to receive the data packets and perform data unpacking, IQ data processing, time delay estimation, clock calibration and positioning calculation, and output positioning results.

[0054] The sensing module is used to synchronously sense and collect radiation source IQ data through the antenna, record timestamps, and package data packets;

[0055] A clock and trigger signal source, used to receive the synchronization command through the data router and generate a trigger signal and a clock signal;

[0056] The signal buffer splitter is used to divide the trigger signal into N trigger signals and the clock signal into N clock signals.

[0057] The trigger signal cable is used to transmit the N trigger signals to the N base stations respectively;

[0058] The clock cable is used to synchronously transmit the N clock signals to the N base stations respectively;

[0059] The data transmission line is used to send the positioning command to each of the base stations and to transmit the data packet to the data router, through which the data packet is transmitted to the computer terminal.

[0060] Preferably, the parameters include the center frequency of the target radiation source, the sampling frequency, the sampling duration, and the average number of times.

[0061] Preferably, the IQ data processing specifically includes obtaining time delay estimation data through data standardization, interpolation, and filtering.

[0062] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a TDOA short baseline positioning method and system with precise synchronization of clock and trigger signals. The design splitter divides one clock and trigger signal source into multiple paths, and transmits the clock and trigger synchronization signals through wired cables. The signal buffer splitter ensures that the clock and trigger signals between each base station are completely synchronized. Based on engineering hardware and algorithms, the synchronization signal error of each TDOA base station is guaranteed to be less than 1 nanosecond. In terms of mechanism and practical application, it achieves precise positioning of short-baseline TDOA at a distance of hundreds of meters. The base station is easy to deploy and has high positioning accuracy. It can be applied to the precise positioning of radiation sources in small fixed areas such as airports, factories, and important facilities, or in scenarios requiring rapid deployment such as vehicle-mounted and ship-mounted systems. Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0064] Figure 1 The attached figure is a schematic diagram of the system structure provided by the present invention. Detailed Implementation

[0065] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] This invention discloses a short baseline positioning method for TDOA with precise synchronization of clock and trigger signal, comprising the following steps:

[0067] S1. Obtain the coordinate positions of N base stations, obtain the coordinate position and center frequency of the calibration source, and send synchronization instructions for clock and trigger signals, where N≥3;

[0068] S2. Receive synchronization instructions and generate N trigger signals and N clock signals, and transmit them to N base stations respectively;

[0069] S3. Set parameters and send positioning instructions to each base station. Each base station synchronously collects radiation source IQ data and records timestamps, and packages the IQ data and timestamps into a data packet and uploads it.

[0070] S4. Receive data packets and perform data unpacking, IQ data processing, delay estimation, clock calibration, and positioning calculation, and output the positioning result.

[0071] In this implementation, the radiation sources in S3 include a calibration source and a target radiation source.

[0072] In practical applications, the calibration source is a radiation source with a known location and frequency. It can be a signal emitted by one's own signal source, or it can be a public radio station, communication base station, etc.

[0073] In this embodiment, the trigger signal is 1PPS and the clock signal is 10M.

[0074] To further implement the above technical solution, the parameters include the center frequency of the target radiation source, the sampling frequency, the sampling duration, and the average number of samplings.

[0075] To further implement the above technical solution, the specific content of IQ data processing in S4 includes obtaining time delay estimation data through data standardization, interpolation, and filtering.

[0076] In this embodiment, data standardization ensures that the data is complete and has a mean of zero, and transforms the I and Q data into a single set of data; interpolation increases the sample size of the data, improving the continuity and accuracy of the data; filtering eliminates random noise errors in the data; finally, a set of data is obtained for time delay estimation.

[0077] To further implement the above technical solution, the specific content of delay estimation in S4 includes:

[0078] x i (n)=s(n)+v i (n)

[0079] x j (n)=αs(nE t )+v j (n)

[0080] Where, x i (n) and x j s(n) represents the time delay estimation data for base station i and base station j, respectively, where n is the recorded timestamp, s(n) is the received radiation source signal, and E t The theoretical time delay difference between base stations is given by α, where α is the attenuation factor and v is the base station. i (n) and v j (n) represents the noise received by base station i and base station j;

[0081] The received signals from base station i and base station j satisfy the cross-correlation function R. 12 (τ):

[0082]

[0083] Where τ is the estimated time delay difference, and ψ(f) is the generalized cross-correlation function. Let be the cross-power spectral density function of the two signals;

[0084] ψ(f)=H(f)H * (f)

[0085] H(f) is the weighting function;

[0086] When τ=E t There is a maximum value R. 12 (τ), where τ is the estimated value of the time delay difference, i.e.

[0087]

[0088] To further implement the above technical solution, the specific details of clock calibration in S4 include:

[0089] The theoretical value E of the time delay difference of the calibration source is calculated based on the coordinate position of the calibration source. ct Calculate the estimated time delay difference of the calibration source. Estimated time delay difference between the calibration source and the target source. and theoretical value E ct System error for obtaining time delay estimation The precise estimate of the time delay difference of the target radiation source in This is an estimate of the time delay difference of the target radiation source.

[0090] In this embodiment, the trigger signal cables and clock cables of different base stations have the same length and specifications. If they are different, the transmission signal delay difference of different trigger signal cables and the transmission signal delay difference of different clock cables are measured experimentally. The delay difference is E. l ,but Expand to

[0091] To further implement the above technical solution, the specific content of the positioning solution in S4 includes:

[0092]

[0093] Where the coordinates of the radiation source are (x, y), R i Let be the distance from the i-th base station to the radiation source;

[0094] E ij =E i -E j

[0095] R ij =cE ij

[0096] E i and E j E represents the time it takes for the signal to arrive at base stations i and j, respectively. ij R is the theoretical value of the time delay difference between base stations i and j. ij Let be the theoretical value of the distance difference between base stations i and j, and c be the speed of radio wave propagation.

[0097] f i (x,y) represents the difference between the distances from the i-th base station and base station 1 to the radiation source:

[0098]

[0099] Where: i = 1, 2, ..., N, N is the number of base stations, (X i ,Y i () represents the coordinates of the base station;

[0100] Distance difference between the i-th base station and base station 1 ε is the estimated distance difference from the actual measurement. i1 To estimate the error;

[0101] f i Expanding (x,y) into a Taylor series at (x0,y0) and keeping only the first two terms, we get:

[0102]

[0103]

[0104] Where (x0, y0) is an initial value, then x = x0 + δ x y=y0+δ y f i，0 f i The function value of (x,y) at (x0,y0) can be expressed in matrix form as follows:

[0105] Aδ=R+e

[0106]

[0107]

[0108]

[0109]

[0110] Solving the above equation using the weighted least squares method, we obtain the solution as follows:

[0111] δ=[A T Q -1 A] -1 A T Q -1 R

[0112] Where Q is the TDOA covariance matrix;

[0113] Let x1 = x0 + δ x y1=y0+δ y Repeat the above process until δ x and δ y Small enough and satisfying a pre-set threshold ε, such that At this point, the radiation source location (x) obtained after k iterations is... k ,y k This is the estimated location.

[0114] In practical applications, selecting three base stations from N base stations allows for two-dimensional positioning of the short baseline TDOA radiation source, while setting N base stations to four base stations allows for three-dimensional positioning of the short baseline TDOA radiation source.

[0115] A TDOA short baseline positioning system with precise synchronization of clock and trigger signal includes N base stations, N cable bundles, a central station and a computer terminal, where N≥3;

[0116] Each base station includes an antenna and a sensing module; each bundle of cables includes a trigger signal cable, a clock cable, and a data transmission line; and the central station includes a clock and trigger signal source, a signal buffer splitter, and a data router.

[0117] The computer terminal is used to obtain the coordinate positions of N base stations, obtain the coordinate position and center frequency of the calibration source, and send synchronization instructions for clock and trigger signals, where N≥3. It is also used to set parameters and send positioning instructions to the central station through the data router. It is also used to receive data packets and perform data unpacking, IQ data processing, time delay estimation, clock calibration and positioning calculation, and output positioning results.

[0118] The sensing module is used to synchronously sense and collect IQ data of the radiation source through the antenna, record timestamps, and package data packets;

[0119] A clock and trigger signal source, used to receive synchronization instructions through a data router and generate trigger and clock signals;

[0120] A signal buffer splitter is used to split a trigger signal into N trigger signals and a clock signal into N clock signals.

[0121] Trigger signal cables are used to transmit N trigger signals to N base stations respectively;

[0122] Clock cable, used for synchronously transmitting N clock signals to N base stations respectively;

[0123] The data transmission line is used to send positioning commands to various base stations and also to transmit data packets to the data router, which then transmits the data packets to the computer terminal.

[0124] In practical applications, clock and trigger signal sources are GPS / BeiDou receivers, crystal oscillators, etc.

[0125] In this embodiment, the central station also includes a power supply for simultaneously powering the clock and trigger signal sources, the signal buffer splitter, and the data router.

[0126] To further implement the above technical solution, the parameters include the center frequency of the target radiation source, the sampling frequency, the sampling duration, and the average number of samplings.

[0127] To further implement the above technical solution, the specific content of IQ data processing includes obtaining time delay estimation data through data standardization, interpolation, and filtering.

[0128] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0129] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A short baseline positioning method for TDOA with precise synchronization of clock and trigger signal, characterized in that, Includes the following steps: S1. Obtain the coordinate positions of N base stations, obtain the coordinate position and center frequency of the calibration source, and send synchronization instructions for clock and trigger signals, where N≥3; S2. Receive the synchronization command and generate N trigger signals and N clock signals, and transmit them to N base stations respectively; S3. Set parameters and send positioning instructions to each base station. Each base station synchronously collects radiation source IQ data and records timestamps, and packages the IQ data and timestamps into a data packet and uploads it. S4. Receive the data packet and perform data unpacking, IQ data processing, time delay estimation, clock calibration and positioning calculation, and output the positioning result; The specific details of the time delay estimation described in S4 include: ； ； in, and Base stations i and base stations j Delay estimation data, For the recorded timestamp, For the received radiation source signal, E t This represents the theoretical time delay difference between base stations. As the attenuation factor, Harmony Base station i and base station j Received noise; base station i and base stations j The received signal satisfies the cross-correlation function R ij (τ): ； in, To estimate the time delay difference, For generalized cross-correlation function, Let be the cross-power spectral density function of the two signals; ψ(f)=H(f)H * (f); It is a weighted function; When τ=E t There is a maximum value R. ij (τ), This is an estimate of the time delay difference, i.e. ； The specific content of the positioning solution described in S4 includes: ； Wherein, the coordinates of the radiation source are Base station The coordinates are , R i For the first The distances from each base station to the radiation source, including: , Number of base stations; AND ij =And i -AND j ; R ij =cE ij ; E i and E j The signals arrive at the base station respectively and Time, E ij For base stations and The theoretical value of the time delay difference between them R ij For base stations and The theory of distance difference The speed of radio wave propagation; For the first The difference between the distances from base station 1 and base station 2 to the radiation source: ； No. Distance difference between each base station and base station 1 , ε is the estimated distance difference from the actual measurement. i1 To estimate the error; Will exist Expanding the Taylor series and keeping only the first two terms, we get: ； ； in, If it is an initial value, then y = y0 + δ y , for exist The function value at point , the above formula can be written in matrix form as: ； ； ； ； ； Solving the above equation using the weighted least squares method, we obtain the solution as follows: ； in The covariance matrix of TDOA; make Repeat the above process until... and Small enough and meets a pre-set threshold , making The location of the radiation source (x) obtained after k iterations k ,y k This is the estimated location.

2. The TDOA short baseline positioning method with precise synchronization of clock and trigger signal according to claim 1, characterized in that, The parameters include the center frequency of the target radiation source, the sampling frequency, the sampling duration, and the average number of samplings.

3. The TDOA short baseline positioning method with precise synchronization of clock and trigger signal according to claim 1, characterized in that, The specific content of IQ data processing in S4 includes obtaining time delay estimation data through data standardization, interpolation, and filtering.

4. The TDOA short baseline positioning method with precise synchronization of clock and trigger signal according to claim 1, characterized in that, The specific details of clock calibration described in S4 include: The theoretical value E of the time delay difference of the calibration source is calculated based on the coordinate position of the calibration source. ct Calculate the estimated time delay difference of the calibration source. Estimated time delay difference between the calibration source and the target source. and theoretical value E ct System error for obtaining time delay estimation Then the accurate estimate of the time delay difference of the target radiation source. in This is an estimate of the time delay difference of the target radiation source.

5. A TDOA short baseline positioning system with precise synchronization of clock and trigger signal, characterized in that, It includes N base stations, N cable bundles, a central station, and computer terminals, where N ≥ 3; Each of the base stations includes an antenna and a sensing module, each of the cable bundles includes a trigger signal cable, a clock cable and a data transmission line, and the central station includes a clock and trigger signal source, a signal buffer splitter and a data router; The computer terminal is used to obtain the coordinate positions of N base stations, obtain the coordinate position and center frequency of the calibration source, and send synchronization instructions for clock and trigger signals, where N≥3. It is also used to set parameters and send positioning instructions to the central station through the data router. It is also used to receive the data packets and perform data unpacking, IQ data processing, time delay estimation, clock calibration and positioning calculation, and output positioning results. The sensing module is used to synchronously sense and collect radiation source IQ data through the antenna, record timestamps, and package data packets; A clock and trigger signal source, used to receive the synchronization command through the data router and generate a trigger signal and a clock signal; The signal buffer splitter is used to divide the trigger signal into N trigger signals and the clock signal into N clock signals. The trigger signal cable is used to transmit the N trigger signals to the N base stations respectively; The clock cable is used to synchronously transmit the N clock signals to the N base stations respectively; The data transmission line is used to send the positioning command to each of the base stations, and also to transmit the data packet to the data router, and the data packet is transmitted to the computer terminal through the data router; The specific content of the time delay estimation includes: ； ； in, and Base stations i and base stations j Delay estimation data, For the recorded timestamp, For the received radiation source signal, E t This represents the theoretical time delay difference between base stations. As the attenuation factor, Harmony Base station i and base station j Received noise; base station i and base stations j The received signal satisfies the cross-correlation function : in, To estimate the time delay difference, For generalized cross-correlation function, Let be the cross-power spectral density function of the two signals; ψ(f)=H(f)H * (f); H(f) is the weighting function; When τ=E t There is a maximum value R. ij (τ), This is an estimate of the time delay difference, i.e. ； The specific content of the location calculation includes: ； Wherein, the coordinates of the radiation source are Base station The coordinates are , R i For the first The distances from each base station to the radiation source are given, where i = 1, 2, ..., N. Number of base stations; AND ij =And i -AND j ; R ij =cE ij ; and The signals arrive at the base station respectively and Time, E ij For base stations and The theoretical value of the time delay difference between them R ij For base stations and The theory of distance difference The speed of radio wave propagation; For the first The difference between the distances from base station 1 and base station 2 to the radiation source: ； No. Distance difference between each base station and base station 1 , ε is the estimated distance difference from the actual measurement. i1 To estimate the error; Will Expanding the Taylor series at (x0, y0) and keeping only the first two terms, we get: ； ； in, If it is an initial value, then y = y0 + δ y , for exist The function value at point , the above formula can be written in matrix form as: ； ； ； ； ； Solving the above equation using the weighted least squares method, we obtain the solution as follows: δ=[A T Q -1 A] -1 A T Q -1 R; in The covariance matrix of TDOA; Let x1 = x0 + δ x y1=y0+δ y Repeat the above process until... and Small enough and meets a pre-set threshold , making The location of the radiation source (x) obtained after k iterations k ,y k This is the estimated location.

6. A TDOA short baseline positioning system with precise synchronization of clock and trigger signal according to claim 5, characterized in that, The parameters include the center frequency of the target radiation source, the sampling frequency, the sampling duration, and the average number of samplings.

7. A TDOA short baseline positioning system with precise synchronization of clock and trigger signal according to claim 5, characterized in that, The specific content of the IQ data processing includes obtaining time delay estimation data through data standardization, interpolation, and filtering.

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