A target positioning method based on compensating TDoA measurement error

Abstract

The present invention discloses a target positioning method based on compensating TDoA measurement errors, comprising: step S1, obtaining the position coordinates of each base station, the TDoA measurement values ​​of the target signal between each base station, and a set of candidate compensation values ​​of TDoA; step S2, each TDoA measurement value is compensated by using the currently selected compensation value, and the distance difference corresponding to each compensated TDoA measurement value is calculated; step S3, according to the distance difference and the position coordinates of each base station, a positioning equation group about the target position coordinates is solved; step S4, the solution of the positioning equation group is screened, if the positioning equation group has a real number solution with Z>0, the real number solution is retained and added to the set ∑; step S5, judging whether the compensation amount has been traversed; if the judgment result is that the compensation amount has been traversed, executing step S6; if the judgment result is that the compensation amount has not been traversed, executing step S2 after updating; step S6, calculating the average value of the set ∑.

Description

Technical Field

[0001] The present invention relates to the field of wireless positioning technology, and in particular to a target positioning method based on compensating TDoA measurement error. Background Art

[0002] Wireless positioning technology is a technology that determines the location of a target through wireless signals. This technology measures the signal propagation time and propagation angle in the wireless communication network as positioning parameters, and determines the location of the target based on the relationship between the above parameters and the location of the positioning target. In addition, wireless positioning technology is the basis of many existing businesses and future services, including vehicle navigation, property management, emergency rescue, intrusion detection, intelligent perception, etc., and has great development prospects and application value.

[0003] Traditional wireless positioning technology mainly relies on the global navigation satellite system for positioning. This positioning technology has a good effect in open areas with good signals. However, this method also has some defects that cannot be ignored. In areas with harsh environments or many obstructions, the positioning results are prone to large errors, which seriously affects the normal positioning of the target. With the continuous development of mobile communication systems, current mobile communication systems can provide a variety of services, including terminal positioning services, and base stations are deployed on the ground and on the top of high-rise buildings. They are widely distributed, so that communication equipment distributed in various locations can be positioned through communication with ground base stations.

[0004] In existing communication systems, positioning based on the time difference of arrival (TDoA) of signals is widely used due to its advantages such as simple communication process, simple measurement process, low clock synchronization requirements, and low complexity of required equipment. Positioning based on TDoA is based on the scenario where the signal propagation path is the line of sight (LOS) path. TDoA corresponds to the distance difference between the positioning target and the base stations. Multiple hyperbolic surfaces with the base stations as the focus can be constructed from the distance difference. The position of the target can be obtained by calculating the common intersection of each surface, that is, the position of the target can be obtained by solving the relationship between itself and each distance difference. However, due to the possible existence of obstacles in the environment and the change of refractive index in the atmosphere, the signal propagation path is not necessarily the LOS path. Therefore, the TDoA measurement value of the signal usually has errors, resulting in the possibility that multiple surfaces do not intersect at the same point. At this time, the above equations have no solution, making the positioning technology based on TDoA invalid. In this regard, this paper proposes a target positioning method by compensating for the TDoA measurement error to solve the problem that the current TDoA positioning method is too ideal. Summary of the invention

[0005] In order to solve the limitations and defects of the prior art, the present invention provides a target positioning method based on compensating TDoA measurement error, comprising:

[0006] Step S1: Obtain input information, the input information including the location coordinates of each base station, the TDoA measurement value of the target signal between each base station, and a set of candidate compensation values ​​for TDoA ;

[0007] Step S2: Each TDoA measurement value is compensated using the currently selected compensation amount, and the distance difference corresponding to each compensated TDoA measurement value is calculated;

[0008] Step S3: according to the distance difference and the position coordinates of each base station, solve the target position coordinates ( x , y , z ), the positioning equation group is expressed as follows:

[0009] ,

[0010] in, It is n -1 distance difference corresponding to the compensated TDoA measurement value, , N is the number of base stations involved in target positioning, n The location coordinates of the base stations are ( x n , y n , z n );

[0011] Step S4: Screen the solution of the positioning equation group. If the positioning equation group exists The real number solution is retained and added to the set In the above mentioned collection Initialize to an empty set;

[0012] Step S5, judging whether the compensation amount has been traversed;

[0013] If the judgment result is that the compensation amount has been traversed, step S6 is executed; if the judgment result is that the compensation amount has not been traversed, the compensation amount in this round of cycle is updated within the range of the candidate compensation amount set, and step S2 is executed after the update is completed;

[0014] Step S6: Calculate the set The average value of

[0015] Step S7: The average value of is taken as the final target positioning result.

[0016] Optionally, the step S1 includes:

[0017] The measurement error range of TDoA is set to , No. k The candidate compensation amount is set to ,in is the step length, In the first iteration, all TDoA measurements are selected As compensation for measurement error.

[0018] Optionally, step S2 includes:

[0019] choose As the n - 1 TDoA measurement The compensation amount after compensation is ;

[0020] No. n -1 The distance difference corresponding to the compensated TDoA measurement value is ,in c =3×10 8 m / s is the speed of light.

[0021] Optionally, step S5 includes:

[0022] Determine whether all TDoA measurement values ​​have been compensated by selecting each candidate compensation amount;

[0023] If the judgment result is that all TDoA measurement values ​​have selected each candidate compensation amount for compensation, execute step S6; if the judgment result is that all TDoA measurement values ​​have not selected each candidate compensation amount for compensation, the compensation amount in this round of cycle is updated within the range of the candidate compensation amount set, and step S2 is executed after the update is completed.

[0024] The present invention has the following beneficial effects:

[0025] The present invention provides a target positioning method based on compensating TDoA measurement errors, comprising: step S1, obtaining the position coordinates of each base station, the TDoA measurement values ​​of the target signal between each base station, and a set of candidate compensation values ​​of TDoA; step S2, each TDoA measurement value is compensated by using the currently selected compensation value, and the distance difference corresponding to each compensated TDoA measurement value is calculated; step S3, according to the distance difference and the position coordinates of each base station, solving the positioning equation group about the target position coordinates; step S4, screening the solution of the positioning equation group, if the positioning equation group exists The real number solution of , keep the real number solution and add it to the set Step S5: determine whether the compensation amount has been traversed; if the judgment result is that the compensation amount has been traversed, execute step S6; if the judgment result is that the compensation amount has not been traversed, update the compensation amount in this round of cycle within the range of the candidate compensation amount set, and execute step S2 after the update is completed; Step S6: calculate the set Step S7: set The average value of is taken as the final target positioning result. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A scene model diagram of a target positioning method based on compensating TDoA measurement errors provided in Embodiment 1 of the present invention.

[0027] Figure 2 This is a flow chart of a target positioning method based on compensating TDoA measurement error provided in Embodiment 1 of the present invention.

[0028] Figure 3 This is an error curve diagram of the target positioning method based on compensating TDoA measurement error provided in the first embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solution of the present invention, the target positioning method based on compensating for TDoA measurement error provided by the present invention is described in detail below with reference to the accompanying drawings. Example

[0030] The target positioning method based on compensating TDoA measurement error provided in this embodiment locates the target in three-dimensional space according to the TDoA measurement value of the signal from the target position between each base station, that is, solves its three-dimensional space coordinates ( x , y , z ). Considering that there are three unknowns in the three-dimensional spatial position coordinates, and the measurement of one TDoA value requires two base stations, if the solution of the position coordinates is to be unique, the TDoA-based positioning technology requires at least four base stations. For example, when the number of base stations is 4, the target positioning scenario model is as follows Figure 1 shown.

[0031] set up ,but Figure 1 middle Indicates The distance between the base station and the target, N is the number of base stations involved in target positioning, The location coordinates of the base stations are , the base station position is known, and the target height coordinates are assumed to bez and the height coordinates of the base station z n The target positioning method based on compensating TDoA measurement error provided by this embodiment is described in detail below.

[0032] The core idea of ​​the target positioning method based on compensating TDoA measurement error provided in this embodiment is to compensate for the TDoA measurement error so that the positioning equations established based on the compensated TDoA have real number solutions, thereby obtaining the position coordinates of the target. The flowchart of the target positioning method based on compensating TDoA measurement error provided in this embodiment is as follows: Figure 2 shown.

[0033] exist Figure 2 The input of this embodiment includes the position coordinates of each base station, the TDoA measurement value of the target signal between each base station, and the candidate compensation amount set of TDoA Among them, the number of elements in the candidate compensation set is K With element value The selection of should satisfy the following requirements: Try to make the positioning equations established by adding the TDoA measurement value to the compensation have real solutions, and the compensation Should not be set too large, Candidate compensation amount The value of can be set to: the common TDoA error value obtained from experience, the uniform sampling points within the TDoA error range, etc. For example, assuming that the error range of the measured TDoA is , then k The candidate compensation amount is set to ,in is the step length, Before the positioning algorithm is executed, all TDoA measurements are selected by default. As compensation for measurement error.

[0034] exist Figure 2 In the "TDoA Compensation" module in the , each TDoA measurement value is compensated using the currently selected compensation amount. For example, if you select As the n - 1 TDoA measurement The compensation amount is, then the result after compensation is Then, in the "Calculate distance difference corresponding to TDoA" module, the distance difference corresponding to each compensated TDoA measurement value is calculated. n -1 The distance difference corresponding to the compensated TDoA measurement value is ,in c = 3 × 10 8 m / s is the speed of light.

[0035] for Figure 2 In the "Solving the Equation Group About the Target Position Coordinates" module, this embodiment solves the equation group about the target position coordinates ( x , y , z ) is the positioning equation group, where the equation group is as follows:

[0036] ,

[0037] Figure 2 The "Retain real solutions with height coordinates greater than zero" module in the equation system screens the solutions of the equation system: If the equation system exists If there is a real number solution to , it is retained and added to the set In, collection Initialized to an empty set.

[0038] When each TDoA measurement value has selected each candidate compensation amount for compensation, it is judged that the compensation amount has completed the traversal; otherwise, it is judged that the compensation amount has not completed the traversal, and the compensation amount in this round of loop is updated within the set range of the candidate compensation amount, and then the next round of TDoA compensation is performed. After the traversal is completed, the set is calculated and takes it as the final target positioning result.

[0039] The simulation of this embodiment is carried out using the MatlabR2020a platform, and the hardware device is a laptop computer equipped with an AMD Ryzen 5 4600U CPU and 16GB of RAM. The test range of the target location is x ∈ [-200m, 1200m], y ∈ [-100m, 1250m], z ∈ [200m, 800m], the test position is the position obtained by sampling the x, y, and z coordinates at intervals of 50m within the above range. The candidate compensation amount of TDoA is set as the sampling point within the TDoA error range. The error range of TDoA and the corresponding sampling interval are shown in Table 1:

[0040] Table 1 Error range of TDoA and corresponding sampling interval in simulation

[0041] ,

[0042] In this embodiment, a total of 4 base stations are set to participate in positioning in the simulation, and their position coordinates are (1m, 1m, 1m), (1100m, 50m, 3m), (1050m, 1150m, 2m), (-100m, 1100m, 1m). TDoA is set to obey a uniform distribution within the error range, and 1000 Monte Carlo simulations are performed for each TDoA error range and each target test position.

[0043] The curves of the target positioning horizontal error, vertical error, and total error of the target positioning method based on compensating TDoA measurement error proposed in this embodiment changing with the TDoA error range are shown in FIG. Figure 3 As shown in the figure, the horizontal axis is the absolute value of the end point of the error range. For example, 70 means that the error range of the measured TDoA is [-70ns, 70ns]. Figure 3 It can be seen that the target positioning error increases with the increase of the TDoA error range, and the horizontal positioning error is smaller than the vertical positioning error in any TDoA error range.

[0044] In addition, considering that the sampling intervals of candidate compensation amounts under different TDoA error ranges are different, the corresponding number of candidate compensation amounts is also different. In this regard, the running time of the target positioning method based on compensating TDoA measurement error proposed in this embodiment under different numbers of candidate compensation amounts is shown in Table 2. It can be seen from Table 2 that the running time of this embodiment is shortened as the number of candidate compensation amounts decreases.

[0045] Table 2 Running time for different numbers of candidate compensations

[0046] ,

[0047] The present embodiment provides a target positioning method based on compensating TDoA measurement errors, including: step S1, obtaining the position coordinates of each base station, the TDoA measurement values ​​of the target signal between each base station, and a set of candidate compensation values ​​for TDoA; step S2, each TDoA measurement value is compensated using the currently selected compensation value, and the distance difference corresponding to each compensated TDoA measurement value is calculated; step S3, according to the distance difference and the position coordinates of each base station, solving the positioning equation group about the target position coordinates; step S4, screening the solutions of the positioning equation group, if the positioning equation group exists The real number solution of , keep the real number solution and add it to the set Step S5: determine whether the compensation amount has been traversed; if the judgment result is that the compensation amount has been traversed, execute step S6; if the judgment result is that the compensation amount has not been traversed, update the compensation amount in this round of cycle within the range of the candidate compensation amount set, and execute step S2 after the update is completed; Step S6: calculate the set Step S7: set The average value of is taken as the final target positioning result.

[0048] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A target positioning method based on compensating TDoA measurement error, characterized in that: include: Step S1: Obtain input information, the input information including the location coordinates of each base station, the TDoA measurement value of the target signal between each base station, and a set of candidate compensation values ​​for TDoA ; Set the measurement error range of TDoA to , No. k The candidate compensation amount is set to ,in is the step length, In the first iteration, all TDoA measurements are selected As compensation for measurement errors; Step S2: Each TDoA measurement value is compensated using the currently selected compensation amount, and the distance difference corresponding to each compensated TDoA measurement value is calculated; Step S3: according to the distance difference and the position coordinates of each base station, solve the target position coordinates ( x , y , z ), the positioning equation group is expressed as follows: ， in, It is n -1 distance difference corresponding to the compensated TDoA measurement value, , N is the number of base stations involved in target positioning, n The location coordinates of the base stations are ( x n , y n , z n ); Step S4: Screen the solution of the positioning equation group. If the positioning equation group exists The real number solution is retained and added to the set In the above mentioned collection Initialize to an empty set; Step S5, judging whether the compensation amount has been traversed; If the judgment result is that the compensation amount has been traversed, step S6 is executed; if the judgment result is that the compensation amount has not been traversed, the compensation amount in this round of cycle is updated within the range of the candidate compensation amount set, and step S2 is executed after the update is completed; Step S6: Calculate the set The average value of Step S7: The average value of is taken as the final target positioning result.

2. The target positioning method based on compensating TDoA measurement error according to claim 1, characterized in that: The step S2 comprises: choose As the n - 1 TDoA measurement The compensation amount after compensation is ; No. n -1 The distance difference corresponding to the compensated TDoA measurement value is ,in c =3×10 8 m / s is the speed of light.

3. The target positioning method based on compensating TDoA measurement error according to claim 2, characterized in that: The step S5 comprises: Determine whether all TDoA measurement values ​​have been compensated by selecting each candidate compensation amount; If the judgment result is that all TDoA measurement values ​​have selected each candidate compensation amount for compensation, execute step S6; if the judgment result is that all TDoA measurement values ​​have not selected each candidate compensation amount for compensation, the compensation amount in this round of cycle is updated within the range of the candidate compensation amount set, and step S2 is executed after the update is completed.

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