A multi-station time difference positioning method

Abstract

The application discloses a kind of inter-station relative distance assisted multi-station time difference positioning method, belong to passive positioning field.It includes: constructing multi-station time difference positioning data model;Determine the position of each observation station, according to the radar signal arrival time measured to each observation station, determine the radar signal arrival time difference of each slave station relative to master station, determine the relative distance of each slave station and master station;According to the position of each observation station, the radar signal arrival time difference of each slave station relative to master station and the relative distance of each slave station and master station, establish positioning equation group;Using pseudo-inverse method to solve positioning equation group, obtain radar target position.This method introduces the auxiliary information of inter-station relative distance in the solving process of multi-station time difference positioning equation group, and can effectively improve the positioning accuracy.The positioning performance of the application is high, and the improvement of positioning accuracy increases with the decrease of time difference error and relative distance error, decreases with the decrease of position error, and basically does not change with baseline length.

Description

Technical Field

[0001] This invention belongs to the field of passive positioning technology, specifically a multi-station time difference positioning method. Background Technology

[0002] Compared to active positioning, multi-station time difference positioning has advantages such as strong concealment, high positioning accuracy, and long operating range. It can be used for intelligence reconnaissance, guiding electronic jamming, and precision strikes against enemy weapon platforms, which is of great significance for improving the combat capability and survivability of weapons and equipment in electronic warfare environments.

[0003] Positioning accuracy is the most critical technical indicator for measuring positioning performance, and analyzing the factors affecting positioning accuracy has always been a key focus of multi-station time difference positioning research. The main factors affecting the accuracy of time difference positioning include station deployment method, baseline length, position error, and time difference measurement accuracy (including time synchronization accuracy). Most research on multi-station time difference positioning focuses on how to effectively improve positioning accuracy.

[0004] For Y-shaped, T-shaped, rhomboid, square and various irregular station layouts, the geometric dilution of precision (GDOP) of their positioning accuracy varies greatly, and the distribution of fuzzy and unsolvable regions is also different. Among them, the Y-shaped station layout has the best positioning performance; the longer the baseline length, the higher the positioning accuracy, but the baseline length cannot be too long due to factors such as inter-station communication; the smaller the station site error and the smaller the time difference error, the higher the positioning accuracy (1. Chen Yongguang, Li Changjin, Li Xiuhe. Accuracy analysis and calculation model of three-station time difference positioning[J]. Acta Electronica Sinica, 2004, 32(9): 1452-1455. 2. Zhang Zhengchao, Tong Li. Accuracy analysis of four-station time difference passive positioning[J]. Journal of China Academy of Electronics Science, 2010, 5(6): 582-585. 3. Huang Jinfeng, Han Yan, Wang Liming. Influence of passive time difference positioning station layout on positioning accuracy[J]. Firepower and Command Control, 2009, 34(10): 33-35. 4. Yu Zhiqiang, Wang Hongyuan, Wu Wen. Research on the deployment of four-station time difference positioning[J]. Journal of Electronics, 2005, 33(12): 2308-2311. 5. Wang Han, Zhong Danxing, Zhou Yiyu. Positioning accuracy analysis of irregularly deployed time difference positioning system[J]. Modern Electronics Technology, 2007(7): 19-21. 6. Wang Zhuoqun, Wang Ju, Li Yajun, Li Yanbin, Wei Heng. Accuracy analysis of four-star time difference positioning based on GDOP[J]. Journal of Terahertz Science and Electronic Information, 2020, 18(5): 808-812. 7. Shi Boxiang, Wang Chao, Zheng Xianbao. Research on four-station time difference positioning technology[J]. Fire Control Radar Technology, 2020, 49(2): 17-23. 8. Mao Zexiang, Liang Rupeng. Optimal station deployment for time difference positioning system based on circular probability error [J]. Command Information System and Technology, 2020, 11(4): 74-77.

[0005] Given a fixed set of factors such as station deployment method, baseline length, location accuracy, and time difference accuracy, the accuracy of multi-station time difference positioning is also fixed. The station deployment method and baseline length are limited by the application scenario and communication capabilities. The positions of the main station and each auxiliary station are generally obtained through GPS or BeiDou systems, with accuracy typically in the meter range, making further improvement difficult. Time difference accuracy is affected by the accuracy of arrival time difference measurement and time synchronization accuracy. Arrival time difference measurement accuracy is related to factors such as signal-to-noise ratio, digital sampling rate, and pulse rising edge characteristics. Using time-frequency domain joint time difference measurement technology, the measurement accuracy can reach the 100ps level (9, Jia Xuemei. Research on Fast and High-Precision Time Difference Measurement Technology [D]. [Master's Thesis], Xi'an University of Electronic Science and Technology, 2019). Time synchronization accuracy is closely related to the specific synchronization mechanism. Time synchronization methods based on GPS or BeiDou systems have an accuracy in the 10ns range, while using bidirectional time comparison technology based on pseudocode ranging can achieve a time synchronization accuracy in the 100ps range in a wireless environment, corresponding to a ranging accuracy in the 30mm range. With various error factors difficult to improve further, the accuracy of multi-station time difference positioning is also difficult to enhance. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-station time difference positioning method. This method can effectively improve positioning accuracy by introducing the auxiliary information of the relative distance between stations during the solution of the multi-station time difference positioning equation system.

[0007] The technical solution to achieve the purpose of this invention is: a multi-station time difference positioning method, the specific steps of which are as follows:

[0008] Step 1: Construct a multi-station time difference positioning data model;

[0009] Step 2: Determine the location of each observation station. Based on the radar signal arrival time of each observation station obtained from the measurement, determine the radar signal arrival time difference of each slave station relative to the master station, and determine the relative distance between each slave station and the master station.

[0010] Step 3: Establish a set of positioning equations based on the location of each observation station, the time difference of radar signal arrival of each slave station relative to the master station, and the relative distance between each slave station and the master station;

[0011] Step 4: Solve the positioning equations using the pseudo-inverse method to obtain the radar target position.

[0012] Preferably, determining the radar signal arrival time difference between each slave station and the master station specifically involves:

[0013]

[0014] In the formula, For station P i Compared to the radar signal arrival time difference of the main station, For station P i Detected radar arrival time, The arrival time of the radar signal detected by the main station, i=1,2,3.

[0015] Preferably, time synchronization between the master station and slave stations is achieved through bidirectional pseudocode ranging to determine the relative distance between each slave station and the master station. The specific method is as follows:

[0016] From main station to slave station Send forward ranging signal, slave station A reverse ranging signal is sent to the master station; there is a clock difference between the two stations. ;

[0017] The master station captures and tracks the reverse ranging signal to obtain the time delay between the master station sending the forward ranging signal and receiving the reverse ranging signal. , Includes main site and slave site Physical path delay between From the station Launch equipment delay The main station's receiving equipment latency and the clock difference between the two terminals The specific relationship is as follows:

[0018]

[0019] From the station The time delay between transmitting the reverse ranging signal and receiving the forward ranging signal was measured. The specific relationship is as follows:

[0020]

[0021] in, , Master station and slave station The relative distance between them;

[0022] Based on the time delay between transmitting the forward ranging signal and receiving the reverse ranging signal measured by the master station, and the time delay of the slave station... The time delay between transmitting the reverse ranging signal and receiving the forward ranging signal is measured to obtain the master station and slave station. Clock difference and relative distance:

[0023]

[0024]

[0025] c is the speed of electromagnetic wave propagation. Master station and slave station The clock difference, Master station and slave station The relative distance.

[0026] Preferably, the specific process of establishing the positioning equation system is as follows:

[0027] According to step 2, obtain the main site. Location From the station Location From the station Location From the station Location From the station Compared to the main site Radar signal arrival time difference From the station Compared to the main site Radar signal arrival time difference From the station Compared to the main site Radar signal arrival time difference The positioning equations are obtained as follows:

[0028]

[0029] After sorting, we get:

[0030]

[0031] In the formula:

[0032] (7)

[0033] According to step 2, obtain the main site. Relative distances between each station , , ,remember , , They represent the main site. and from the station The relative distances between them in the x, y, and z directions represent the distances between the main stations. and from the station The relative distance between them in the x-direction is then:

[0034]

[0035] Substituting the relative distance information into the positioning equations, we obtain a new set of positioning equations:

[0036]

[0037] in:

[0038] .

[0039] Preferably, the specific method for solving the positioning equations using the pseudo-inverse method to obtain the radar target position is as follows:

[0040] Write the new set of positioning equations in matrix form:

[0041]

[0042] In the formula,

[0043] , , .

[0044] The solution to the system of equations in matrix form is obtained by using the pseudo-inverse method:

[0045] .

[0046] Compared with the prior art, the significant advantages of this invention are: by combining high-precision time synchronization technology based on pseudocode ranging, this invention effectively improves positioning accuracy by introducing the relative distance between each slave station and the master station when solving the positioning equation set. Attached Figure Description

[0047] Figure 1 It is a multi-station time positioning mathematical model.

[0048] Figure 2 This is a block diagram of the principle of bidirectional pseudocode ranging.

[0049] Figure 3 This is a comparison of the positioning accuracy of conventional time-of-flight positioning and the positioning method proposed in this invention when the positional error is 10m. Figure 3 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 3 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 3 (c) represents the improvement in positioning performance.

[0050] Figure 4 This is a comparison of the positioning accuracy of conventional time-of-flight positioning and the positioning method proposed in this invention when the position error is 5m. Figure 4 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 4 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 4 (c) represents the improvement in positioning performance.

[0051] Figure 5 This is a comparison of the positioning accuracy of conventional time-of-flight positioning and the positioning method proposed in this invention when the positional error is 1m. Figure 5 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 5 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 5 (c) represents the improvement in positioning performance.

[0052] Figure 6 This is a comparison of the positioning accuracy of conventional time-difference positioning and the positioning method proposed in this invention when the time difference error is 20ns. Figure 6 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 6 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 6 (c) represents the improvement in positioning performance.

[0053] Figure 7 This is a comparison of the positioning accuracy of conventional time-difference positioning and the positioning method proposed in this invention when the time difference error is 10ns. Figure 7 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 7 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 7 (c) represents the improvement in positioning performance.

[0054] Figure 8 This is a comparison of the positioning accuracy of conventional time-difference positioning and the positioning method proposed in this invention when the time difference error is 1 ns. Figure 8 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 8 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 8 (c) represents the improvement in positioning performance.

[0055] Figure 9 This is a comparison of the positioning accuracy of conventional time-of-flight positioning and the positioning method proposed in this invention when the relative distance error is 10m. Figure 9 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 9 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 9 (c) represents the improvement in positioning performance.

[0056] Figure 10 This is a comparison of the positioning accuracy of conventional time-of-flight positioning and the positioning method proposed in this invention when the relative distance error is 1m. Figure 10 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 10 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 10 (c) represents the improvement in positioning performance.

[0057] Figure 11This is a comparison of the positioning accuracy of conventional time-of-flight positioning and the positioning method proposed in this invention when the relative distance error is 0.1m. Figure 11 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 11 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 11 (c) represents the improvement in positioning performance.

[0058] Figure 12 This is a comparison of the positioning accuracy of conventional time-difference positioning and the positioning method proposed in this invention when the baseline length is 20km. Figure 12 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 12 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 12 (c) represents the improvement in positioning performance.

[0059] Figure 13 This is a comparison of the positioning accuracy of conventional time-difference positioning and the positioning method proposed in this invention when the baseline length is 10km. Figure 13 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 13 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 13 (c) represents the improvement in positioning performance.

[0060] Figure 14 This is a comparison of the positioning accuracy of conventional time-difference positioning and the positioning method proposed in this invention when the baseline length is 5km. Figure 14 (a) in the diagram represents conventional time difference positioning (GDOP). Figure 14 (b) in the figure represents GDOP, a time difference positioning system based on relative distance. Figure 14 (c) represents the improvement in positioning performance. Detailed Implementation

[0061] The present invention will now be described in further detail with reference to the accompanying drawings.

[0062] Step 1: Construct a mathematical model for multi-station time difference positioning.

[0063] Figure 1 The figure shows a mathematical model for multi-station time difference positioning. For radar target The spatial location of is the quantity to be determined; Main site Spatial location, For the station Spatial location, For the station Spatial location, For the station Its spatial location can be obtained through observation. (Note: The original text appears to be incomplete and contains several typos. A more Main site To radar target distance, For the station To radar target distance, For the station To radar target distance, For the station To radar target distance, For signals from radar targets Dissemination from the main site Time, Main site To radar target and from the station To radar target The distance difference , Main site To radar target and from the station To radar target The distance difference , Main site To radar target and from the station To radar target The distance difference , For the signal from the main station To radar target and signal from the station To radar target The time difference in transmission, and Where c is the speed of electromagnetic wave propagation. , For the signal from the main station To radar target and signal from the station To radar target The time difference in transmission, and , For the signal from the main station To radar target and signal from the station To radar target The time difference in transmission, and .

[0064] Step 2: Determine the location of each observation station. Based on the radar signal arrival time of each observation station obtained from the measurement, determine the radar signal arrival time difference of each slave station relative to the master station, and determine the relative distance between each slave station and the master station.

[0065] Each observation station, including the main station From the station From the station and from the station The location of each observation station is obtained through GPS or the BeiDou global navigation and positioning system.

[0066] Each observation station can measure the arrival time of the radar signal through digital signal detection. The arrival time of the radar signal detected by the main station is denoted as... From the station The detected radar signal arrival time is From the station The detected radar signal arrival time is From the station The detected radar signal arrival time is Then the time difference of radar signal arrival of each slave station relative to the master station can be obtained: , , .

[0067] Main site and from the station From the station From the station High-precision time synchronization is achieved between the two stations through bidirectional pseudocode ranging, with the master station as the primary station. and from the station For example, the block diagram of the two-way pseudocode ranging principle is as follows: Figure 2 As shown, the main site and from the station Main site and from the station The synchronization process is the same and will not be described again. Main site Towards the station Send forward ranging signal, slave station To the main site The backward ranging signal is sent, and there is a clock difference between the two stations. Main site By capturing and tracking the reverse ranging signal, the time delay between transmitting the forward ranging signal and receiving the reverse ranging signal can be obtained. , Including the main site and from the station Physical path delay between From the station Launch equipment delay Main site Receiving device latency and the clock difference between the two terminals The relationship is as follows:

[0068] (1)

[0069] Similarly, from the station The time delay between sending the reverse ranging signal and receiving the forward ranging signal can be measured. :

[0070] (2)

[0071] in, , Main site and from the station The relative distance between them Combining equations (1) and (2), we can obtain the main station and from the station clock difference and relative distance :

[0072] (3)

[0073] (4)

[0074] Similarly, the main site can be obtained. and from the station clock difference and relative distance Main site and from the station clock difference and relative distance ,and , I will not go into details.

[0075] Step 3: Establish a set of positioning equations based on the location of each observation station, the time difference of radar signal arrival of each slave station relative to the master station, and the relative distance between each slave station and the master station.

[0076] According to step 2, obtain the main site. Location From the station Location From the station Location From the station Location From the station Compared to the main site Radar signal arrival time difference From the station Compared to the main site Radar signal arrival time difference From the station Compared to the main site Radar signal arrival time difference The following system of positioning equations can be obtained:

[0077] (5)

[0078] After sorting, we get:

[0079] (6)

[0080] In the formula:

[0081] (7)

[0082] According to step 2, obtain the main site. Relative distances between each station , , ,remember , , They represent the main site. and from the station The relative distances between them in the x, y, and z directions represent the distances between the main stations. and from the station The relative distance between them in the x-direction is then:

[0083] (8)

[0084] Substituting the relative distance information into the positioning set (6), a new set of positioning equations can be obtained:

[0085] (9)

[0086] in:

[0087] (10)

[0088] Step 4: Solve the positioning equations using the pseudo-inverse method to obtain the radar target position.

[0089] Write the system of equations (9) in matrix form:

[0090] (11)

[0091] In the formula,

[0092] , , .

[0093] The solution to the system of equations (11) is obtained by using the pseudo-inverse method:

[0094] (12)

[0095] The effects of the present invention will be further illustrated below with simulation experiments.

[0096] To facilitate characterizing the performance improvement of time difference positioning based on relative distance, the following definition is used:

[0097] (13)

[0098] in, GDOP represents the standard time difference positioning. This invention represents GDOP, a time difference positioning system based on inter-station relative distance assistance. Indicates radar target S and the main station distance, This indicates the improvement in positioning performance. If... This indicates improved positioning accuracy. This indicates a decrease in positioning accuracy. This indicates that the positioning accuracy remained unchanged.

[0099] Using four space stations as a typical configuration, the positioning accuracy of time difference positioning (TDRP) under the same conditions is compared with that of conventional time difference positioning. The simulation analysis examines the positioning performance of TDRP based on relative distance, involving variables such as position error, time difference error, relative distance error, and baseline length. The simulation conditions are shown in the table below:

[0100] Table 1 Simulation Condition Settings

[0101]

[0102] With a fixed time difference error of 10 ns, a relative distance error of 0.1 m, and a baseline length of 10 km, and station position errors of 10 m, 5 m, and 1 m respectively, a comparison of the accuracy of conventional time difference positioning and the positioning method proposed in this invention is shown below. Figure 3 , Figure 4 , Figure 5 As shown.

[0103] from Figure 3 It can be seen that the positioning accuracy of time difference positioning based on relative distance is significantly higher than that of conventional time difference positioning methods. When the time difference error is 10ns, the relative distance error is 0.1m, the baseline length is 10km, and the position error is 10m, the positioning accuracy is improved by about 80% in the entire 100km×100km area.

[0104] comprehensive Figure 3 , Figure 4 and Figure 5With fixed time difference error and relative distance error, as the position error of each station decreases, the positioning accuracy of the method proposed in this invention is still higher than that of conventional time difference positioning methods. However, the improvement in positioning accuracy gradually decreases. This is because as the position error of each station decreases, the positioning accuracy of conventional time difference positioning methods also increases, while the positioning accuracy of the proposed method remains basically unchanged. This indicates that the positioning accuracy of the method proposed in this invention is insensitive to position error.

[0105] With a fixed position error of 10m, a relative distance error of 0.1m, and a baseline length of 10km, and time difference errors of 20ns, 10ns, and 1ns respectively, a comparison of the accuracy of conventional time-difference positioning and the positioning method proposed in this invention is shown below. Figure 6 , Figure 7 , Figure 8 As shown.

[0106] comprehensive Figure 6 , Figure 7 and Figure 8 With fixed position error, relative distance error, and baseline length, the positioning accuracy of the method proposed in this invention is higher than that of conventional time-of-flight (TOF) positioning methods as the time difference error decreases. Furthermore, the improvement in positioning accuracy gradually increases. This is because, as the time difference error decreases, the positioning accuracy of conventional TOF positioning methods remains almost unchanged, indicating that the time difference error is no longer the primary factor causing positioning error. In fact, a 20ns time difference error is equivalent to a 6m position error, which is already less than the actual position error of 10m. Therefore, reducing the time difference error beyond 20ns contributes almost nothing to improving positioning accuracy. However, the positioning accuracy of the method proposed in this invention increases significantly, demonstrating that even with the introduction of relative distance, increasing the time difference error still makes a substantial contribution to improving positioning accuracy.

[0107] With a fixed position error of 10m, a time difference error of 10ns, and a baseline length of 10km, and relative distance errors of 10m, 1m, and 0.1m respectively, a comparison of the accuracy of conventional time-difference positioning and the positioning method proposed in this invention is shown below. Figure 9 , Figure 10 , Figure 11 As shown.

[0108] comprehensive Figure 9 , Figure 10 and Figure 11With fixed position error, time difference error, and baseline length, as the relative distance error decreases, the positioning accuracy of the method proposed in this invention is higher than that of conventional time difference positioning methods, and the improvement in positioning accuracy gradually increases. This is because, although the positioning accuracy of conventional time difference positioning methods also improves as the time difference error decreases, the contribution of introducing relative distance to improving positioning accuracy is relatively higher. It should be noted that when the relative distance error increases from 1m to 0.1m, the improvement in positioning accuracy does not change significantly. This is because, at this point, position error and time difference error have become the main factors restricting positioning accuracy.

[0109] With a fixed position error of 5m, a time difference error of 10ns, and a relative distance error of 1m, and baseline lengths of 20km, 10km, and 5km respectively, a comparison of the accuracy of conventional time-difference positioning and the positioning method proposed in this invention is shown below. Figure 12 , Figure 13 and Figure 14 As shown.

[0110] comprehensive Figure 12 , Figure 13 and Figure 14 It can be seen that the positioning accuracy of the proposed method is higher than that of the conventional time difference positioning method under different baseline lengths, but the improvement in positioning accuracy does not change much, and is basically around 65%.

[0111] Based on the simulation results above, compared with conventional multi-station time difference positioning methods, the positioning method proposed in this invention can effectively improve positioning accuracy. Furthermore, the smaller the position error, the smaller the improvement in positioning accuracy; conversely, the smaller the time difference error and relative distance error, the greater the improvement in positioning accuracy. This is related to the proportion of each error factor.

[0112] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto.

[0113] Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this invention should be included within the protection scope of this invention.

[0114] It should be understood that, in order to simplify the present invention and help those skilled in the art understand its various aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes described in a single embodiment or with reference to a single figure. However, the present invention should not be construed as including all features in the exemplary embodiments as essential technical features of the claims of this patent.

[0115] It should be understood that the modules, units, components, etc., included in the device of one embodiment of the present invention can be adaptively changed to be placed in a device different from that embodiment. Different modules, units, or components included in the device of the embodiment can be combined into a single module, unit, or component, or they can be divided into multiple sub-modules, sub-units, or sub-components.

Claims

1. A multistatic time difference of arrival positioning method, characterized in that, The specific steps are as follows: Step 1: Construct a multi-station time difference positioning data model; Step 2: Determine the location of each observation station. Based on the radar signal arrival time of each observation station obtained from the measurement, determine the radar signal arrival time difference of each slave station relative to the master station, and determine the relative distance between each slave station and the master station. Step 3: Based on the location of each observation station, the time difference of radar signal arrival between each slave station and the master station, and the relative distance between each slave station and the master station, establish a set of positioning equations. Based on Step 2, obtain the master station's location. Location From the station Location From the station Location From the station Location From the station Compared to the main site Radar signal arrival time difference From the station Compared to the main site Radar signal arrival time difference From the station Compared to the main site Radar signal arrival time difference The positioning equations are obtained as follows: Summarized as follows: In the formula: c is the speed of electromagnetic wave propagation. For radar target Spatial location, Master station and slave station The clock difference, Master station and slave station The relative distance; According to step 2, obtain the main site. Relative distances between each station , , ,remember , , They represent the main site. and from the station The relative distances between them in the x, y, and z directions are: Substituting the relative distance information into the positioning equations, we obtain a new set of positioning equations: ； Step 4: Solve the positioning equations using the pseudo-inverse method to obtain the radar target position.

2. The multistatic time difference of arrival positioning method of claim 1, wherein, The specific time difference of radar signal arrival between each slave station and the master station is determined as follows: wherein is the radar signal arrival time difference detected by the slave station P i relative to the master station, is the radar signal arrival time difference detected by the slave station P i detected radar arrival time, is the radar signal arrival time detected by the master station, i = 1, 2, 3.

3. The multi-station time difference positioning method according to claim 1, characterized in that, Time synchronization between the master station and slave stations is achieved through bidirectional pseudocode ranging to determine the relative distance between each slave station and the master station. The specific method is as follows: The master station sends a forward ranging signal to the slave station The slave station sends a reverse ranging signal to the master station The slave station sends a reverse ranging signal to the master station ; The master station captures and tracks the reverse ranging signal to obtain the time delay between the master station sending the forward ranging signal and receiving the reverse ranging signal. , Includes main site and slave site Physical path delay between From the station Launch equipment delay The main station's receiving equipment latency and the clock difference between the two terminals The specific relationship is as follows: slave station measuring a time delay between transmitting the reverse ranging signal and receiving the forward ranging signal in particular relation wherein , is the relative distance between the master and slave stations ​ measuring the time delay between transmitting a forward ranging signal and receiving a reverse ranging signal at the slave station measuring the time delay between transmitting a reverse ranging signal and receiving a forward ranging signal at the master station obtaining the clock difference and the relative distance between the master station and the slave station 。 4. The multistatic time difference of arrival positioning method of claim 1, wherein, The specific method for solving the positioning equations using the pseudo-inverse method to obtain the radar target position is as follows: Write the new set of positioning equations in matrix form: In the formula, ， ， ； The solution to the system of equations in matrix form is obtained by using the pseudo-inverse method: 。 5. The multistatic time difference of arrival positioning method of claim 1, wherein, The location of each observation station is obtained through GPS or the BeiDou global navigation and positioning system.

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