A method for fusion positioning of ground multi-point positioning and inertial navigation based on positioning result accuracy

Abstract

This invention provides a method for ground-based multi-point positioning and inertial navigation fusion positioning based on the accuracy of positioning results. The target vehicle integrates an accelerometer and a gyroscope. At least four base stations for multi-point positioning are deployed around the vehicle. Then, the ground-based multi-point positioning coordinates of the vehicle are obtained through a Time-of-Flight (TOF) algorithm, Kalman filtering, and DBSCAN filtering. Simultaneously, the vehicle measures its own acceleration and angular acceleration in the inertial reference frame using the accelerometer and gyroscope. After double integration, the vehicle's position information is obtained and transformed to the multi-point positioning coordinate system to obtain the inertial navigation positioning coordinates. Finally, the accuracy P of the multi-point positioning result is calculated. mult The final positioning result is L=P. mult L mult +(1-P) mult )L navi This invention is applicable to applications with no fewer than four signal receiving devices and a carrier equipped with inertial navigation functionality, ensuring the real-time performance, stability, and accuracy of positioning results.

Description

Technical Field

[0001] This invention relates to a positioning method, and more particularly to a ground multi-point positioning and inertial navigation fusion positioning method based on the accuracy of positioning results. Background Technology

[0002] Ground-based multipoint positioning technology utilizes the signal transmission time between a target signal transmitter and multiple ground receivers to achieve effective target localization. In principle, multipoint positioning technology does not measure signal strength, but rather the radio signal transmission time (TOA) between the receiver and the target transmitter. However, when there are obstructions between the receiver and transmitter, the TOA value will have some error, and noise interference will occur, making the positioning results unstable and fluctuating. Therefore, adding other auxiliary positioning methods can further improve the accuracy of the positioning.

[0003] An inertial navigation system, also known as an inertial reference system, is an autonomous navigation system that does not rely on external information or radiate energy externally (unlike radio navigation). Inertial navigation systems use a calculation-based navigation method, meaning that the position of a moving object is calculated from its known position using continuously measured heading angles and velocities, thus allowing for continuous measurement of the object's current position. Gyroscopes in an inertial navigation system establish a navigation coordinate system, stabilizing the accelerometer's measurement axis within this system and providing heading and attitude angles. Accelerometers measure the object's acceleration; integrating this acceleration once over time yields the velocity, and integrating the velocity again over time gives the distance. Because navigation information is generated through integration, positioning errors increase over time, resulting in poor long-term accuracy. Therefore, inertial navigation is generally used as an auxiliary positioning method. Summary of the Invention

[0004] This invention aims to provide a method for ground multi-point positioning and inertial navigation fusion positioning based on the accuracy of positioning results. It is applicable to positioning carriers with inertial navigation function and multi-point positioning with more than 3 signal receiving devices. It can effectively improve the problems of unstable positioning results and inaccurate positioning caused by noise interference.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] A method for ground-based multi-point positioning and inertial navigation fusion positioning based on positioning accuracy is disclosed. The target vehicle integrates accelerometers and gyroscopes, enabling inertial navigation. At least N+1 base stations for multi-point positioning are deployed around the vehicle, where N is a natural number not less than 3. N+1 arrival times are obtained by sending radio signals to the base stations. Simultaneously, the vehicle measures its own acceleration and angular acceleration in an inertial reference frame using the accelerometer and gyroscope. These values ​​are integrated over time to obtain the velocity and angular velocity of the moving vehicle. A second integration is then performed to obtain the position information of the tag. This information is then transformed to a ground-based multi-point positioning coordinate system to obtain the inertial navigation positioning coordinate values. The arrival times from the base stations to the vehicle and the inertial navigation positioning coordinate values ​​are then sent to a central control engine. The method is characterized by: running a program in the central control engine based on an algorithm obtained according to the following steps.

[0007] S01: Multiply the arrival time values ​​of the N+1 base stations to the carrier by the signal propagation speed c to obtain the distance D from the N+1 carriers to the base station used for positioning. i Where i is any natural number from 1 to N+1; simultaneously record the inertial navigation positioning coordinate value L. navi ;

[0008] S02: Select 4 base stations from the N+1 base stations used for multi-point positioning and combine them. Let the coordinates of the c-th group of base stations be A. ci Where c is any natural number from 1 to M, and i is any natural number from 1 to 4, the formula for calculating the number of combinations M is:

[0009]

[0010] Calculate the coordinates of base station A c1 ~A c4 The polygon type is determined by whether it is a convex quadrilateral. The number of valid base station combinations, Q, is then obtained, where Q ≤ M. The coordinates of the valid v-th base station group are denoted as A. vj The distance from the carrier to the base station is D. vj , where v is any natural number from 1 to Q, and j is any natural number from 1 to 4;

[0011] S03: Find D v1 ~D v4 The average value of the distance D from the carrier to the base station in the vth combination is obtained. v The calculation formula is:

[0012]

[0013] Then find the smallest D. v Let D k=(D v ) min ,but

[0014]

[0015] Then the k-th base station combination is the optimal combination for multi-point positioning, and the coordinates of the base station are A. kj {X kj ,Y kj Z kj The distance from the carrier to the base station is D. kj , where v is any natural number from 1 to Q, k is a definite natural number from 1 to Q, and j is any natural number from 1 to 4;

[0016] S04: Obtain base station coordinates A k1 ~A k4 and the distance D from the carrier to the base station k1 ~D k4 The Time-of-Flight (TOF) algorithm was used to calculate the coordinates of the carrier's position to be optimized. Then, after removing noise through Kalman filtering and DBSCAN filtering, the final coordinates L of the carrier in the multi-point positioning coordinate system were obtained. mult If the TOF algorithm fails to calculate the positioning coordinates, it outputs a specific invalid coordinate marker L. invalid ;

[0017] S05: Using the average distance D from the carrier to the base station k The distance D between the four base stations forms a diagonal line Ak13 D Ak24 A quarter of the sum of D Ak The accuracy P of the multi-point localization results is obtained by comparison. mult The calculation formula is:

[0018]

[0019]

[0020]

[0021]

[0022] It can be seen from the formula that 0 ≤ P mult ≤1, which matches the description of accuracy;

[0023] S05: The final accuracy P based on the multi-point positioning results mult Perform multi-point positioning coordinates L mult and inertial navigation coordinates L navi The fusion yields the final positioning result L. end The calculation formula is:

[0024] L end =P mult L mult +(1-P mult )L navi (8)

[0025] As a preferred embodiment, the central control engine solves the positioning result of the multi-point positioning system by selecting the optimal combination of 4 base stations.

[0026] Preferably, the central control engine optimizes the ground multi-point positioning results using the Kalman filter algorithm and the DBSCAN algorithm.

[0027] Preferably, the central control engine calculates the accuracy of the multi-point positioning results by using the diagonal distance of the base stations forming a convex quadrilateral and the distance from the carrier to the base station.

[0028] The beneficial effects of this invention are:

[0029] (1) To address the increased error caused by multiple TOAs, the central control engine selects the optimal combination of 4 base stations to solve the positioning result of the multi-point positioning system.

[0030] (2) To reduce the interference of noise on the positioning results, the central control engine optimizes the ground multi-point positioning results through Kalman filtering algorithm and DBSCAN algorithm.

[0031] (3) To calculate the final positioning result more accurately, the central control engine calculates the accuracy of the multi-point positioning result by using the diagonal distance of the base stations that form a convex quadrilateral and the distance from the carrier to the base station. Detailed Implementation

[0032] To make the above objectives, technical solutions, and beneficial effects clearer and more explicit, the present invention will be specifically described below in conjunction with embodiments.

[0033] Example 1

[0034] A ground-based multi-point positioning system is provided, comprising a base station (signal receiving device), a carrier with inertial navigation function (signal transmitting device), and a central control engine. The carrier is carried by the target to be located in a real-world scenario. The system should have at least three base stations.

[0035] A method for ground-based multi-point positioning and inertial navigation fusion positioning based on positioning accuracy is disclosed. The target vehicle integrates accelerometers and gyroscopes, enabling inertial navigation. At least N+1 base stations for multi-point positioning are deployed around the vehicle, where N is a natural number not less than 3. N+1 arrival times are obtained by sending radio signals to the base stations. Simultaneously, the vehicle measures its own acceleration and angular acceleration in an inertial reference frame using the accelerometer and gyroscope. These values ​​are integrated over time to obtain the velocity and angular velocity of the moving vehicle. A second integration is then performed to obtain the position information of the tag. This information is then transformed to a ground-based multi-point positioning coordinate system to obtain the inertial navigation positioning coordinate values. The arrival times from the base stations to the vehicle and the inertial navigation positioning coordinate values ​​are then sent to a central control engine. The method is characterized by: running a program in the central control engine based on an algorithm obtained according to the following steps.

[0036] S01: Multiply the arrival time values ​​of the N+1 base stations to the carrier by the signal propagation speed c to obtain the distance D from the N+1 carriers to the base station used for positioning. i Where i is any natural number from 1 to N+1; simultaneously record the inertial navigation positioning coordinate value L. navi ;

[0037] S02: Select 4 base stations from the N+1 base stations used for multi-point positioning and combine them. Let the coordinates of the c-th group of base stations be A. ci Where c is any natural number from 1 to M, and i is any natural number from 1 to 4, the formula for calculating the number of combinations M is:

[0038]

[0039] Calculate the coordinates of base station A c1 ~A c4 The polygon type is determined by whether it is a convex quadrilateral. The number of valid base station combinations, Q, is then obtained, where Q ≤ M. The coordinates of the valid v-th base station group are denoted as A. vj The distance from the carrier to the base station is D. vj , where v is any natural number from 1 to Q, and j is any natural number from 1 to 4;

[0040] S03: Find D v1 ~D v4 The average value of the distance D from the carrier to the base station in the vth combination is obtained. v The calculation formula is:

[0041]

[0042] Then find the smallest D. v Let D k=(D v ) min ,but

[0043]

[0044] Then the k-th base station combination is the optimal combination for multi-point positioning, and the coordinates of the base station are A. kj {X kj ,Y kj Z kj The distance from the carrier to the base station is D. kj , where v is any natural number from 1 to Q, k is a definite natural number from 1 to Q, and j is any natural number from 1 to 4;

[0045] S04: Obtain base station coordinates A k1 ~A k4 and the distance D from the carrier to the base station k1 ~D k4 The Time-of-Flight (TOF) algorithm was used to calculate the coordinates of the carrier's position to be optimized. Then, after removing noise through Kalman filtering and DBSCAN filtering, the final coordinates L of the carrier in the multi-point positioning coordinate system were obtained. mult If the TOF algorithm fails to calculate the positioning coordinates, it outputs a specific invalid coordinate marker L. invalid ;

[0046] S05: Using the average distance D from the carrier to the base station k The distance D between the four base stations forms a diagonal line Ak13 D Ak24 A quarter of the sum of D Ak The accuracy P of the multi-point localization results is obtained by comparison. mult The calculation formula is:

[0047]

[0048]

[0049]

[0050]

[0051] It can be seen from the formula that 0 ≤ P mult ≤1, which matches the description of accuracy;

[0052] S05: The final accuracy P based on the multi-point positioning results mult Perform multi-point positioning coordinates L mult and inertial navigation coordinates L navi The fusion yields the final positioning result L. end The calculation formula is:

[0053] L end =P mult L mult +(1-P mult )L navi (8)

[0054] Comparative Example 1

[0055] A general ground-based multi-point positioning system is provided, comprising a base station (signal receiving device), a carrier (signal transmitting device), and a central control engine. The carrier is carried by the target to be located in a real-world scenario. The system should have at least three base stations.

[0056] A general ground-based multi-point positioning method involves deploying no fewer than N+1 base stations for multi-point positioning around the target vehicle, where N is a natural number not less than 3. N+1 arrival time values ​​are obtained by sending radio signals to the base stations, and then the arrival times from the N+1 base stations to the vehicle are sent to a central control engine. The method is characterized by running a program in the central control engine based on an algorithm obtained according to the following steps.

[0057] S01: Multiply the arrival time values ​​of the N+1 base stations to the carrier by the signal propagation speed c to obtain the distance D from the N+1 carriers to the base station used for positioning. i , where i is any natural number from 1 to N+1;

[0058] S02: Select 4 base stations from the N+1 base stations used for multi-point positioning and combine them. Let the coordinates of the c-th group of base stations be A. ci Then the distance from the carrier to the base station is D. ci Where c is any natural number from 1 to M, and i is any natural number from 1 to 4, the formula for calculating the number of combinations M is:

[0059]

[0060] S03: The position coordinates L of the carrier when the c-th group of base stations is combined are calculated using the TOF algorithm. c If the positioning coordinates cannot be calculated, then record L. c =L0=(0,0,0), find L c = The number of L0 is R, where 0≤R≤M. Calculate the average value of the carrier's position coordinates when all base stations are combined, and obtain the carrier's positioning coordinates L. The calculation formula is:

[0061]

[0062] A comparison of Comparative Example 1 and Example 1 shows that the ground multi-point positioning and inertial navigation fusion positioning method based on the accuracy of positioning results has the following advantages:

[0063] 1) Because there is an error in the distance from the carrier to the base station, Comparative Example 1 used all N+1 distances, while Example 1 only used the optimal 4 distances. Therefore, when calculating the coordinates of multiple ground positioning points, there is less interference from distance error.

[0064] 2) Example 1 used Kalman filtering and DBSCAN filtering for the preliminary ground multi-point positioning results, while Comparative Example 1 did not. This increased the stability of the positioning coordinates and reduced the interference of noise on the positioning results.

[0065] 3) Example 1 uses ground multi-point positioning accuracy to integrate inertial navigation coordinates and corrects invalid or inaccurate ground multi-point positioning coordinates, while Comparative Example 1 does not, thereby increasing the accuracy of positioning coordinates.

[0066] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for ground multi-point positioning and inertial navigation fusion positioning based on positioning result accuracy, wherein the target vehicle to be positioned integrates accelerometers and gyroscopes and has inertial navigation functions, and no less than N+1 base stations for multi-point positioning are deployed around the vehicle, where N is a natural number not less than 3. N+1 arrival time values ​​are obtained by sending radio signals to the base stations. Simultaneously, the vehicle measures its own acceleration and angular acceleration in the inertial reference frame using accelerometers and gyroscopes, integrates these values ​​once over time to obtain the velocity and angular velocity of the moving vehicle, then performs a second integration to obtain the tag's position information, transforms it to a ground multi-point positioning coordinate system to obtain inertial navigation positioning coordinate values, and then sends the arrival time from the base stations to the vehicle and the inertial navigation positioning coordinate values ​​to a central control engine. The method is characterized by: Run the program in the central control engine based on the algorithm obtained by the following steps: S01: Multiply the arrival time values ​​of the N+1 base stations to the carrier by the signal propagation speed c to obtain the distance d from the N+1 carriers to the base station used for positioning. i Where i is any natural number from 1 to N+1; simultaneously record the inertial navigation positioning coordinate value L. navi ; S02: Select 4 base stations from the N+1 base stations used for multi-point positioning and combine them. Let the coordinates of the c-th group of base stations be A. ci Where c is any natural number from 1 to M, and i is any natural number from 1 to 4, the formula for calculating the number of combinations M is: (1) Calculate the coordinates of base station A c1 ~A c4 The polygon type is determined by whether it is a convex quadrilateral. The number of valid base station combinations, Q, is then obtained, where Q ≤ M. The coordinates of the valid v-th base station group are denoted as A. vj The distance from the carrier to the base station is D. vj , where v is any natural number from 1 to Q, and j is any natural number from 1 to 4; S03: Find D v1 ~D v4 The average value of the distance D from the carrier to the base station in the vth combination is obtained. v The calculation formula is: (2) Then find the smallest D. v Let D k = (D v ) min ,but (3) Then the k-th base station combination is the optimal combination for multi-point positioning, and the coordinates of the base station are A. kj {X kj ,Y kj Z kj The distance from the carrier to the base station is D. kj , where v is any natural number from 1 to Q, k is a definite natural number from 1 to Q, and j is any natural number from 1 to 4; S04: Obtain base station coordinates A k1 ~A k4 and the distance D from the carrier to the base station k1 ~D k4 The Time-of-Flight (TOF) algorithm was used to calculate the coordinates of the carrier's position to be optimized. Then, after removing noise through Kalman filtering and DBSCAN filtering, the final coordinates L of the carrier in the multi-point positioning coordinate system were obtained. mult If the TOF algorithm fails to calculate the positioning coordinates, it outputs a specific invalid coordinate marker L. invalid ; S05: Using the average distance D from the carrier to the base station k The distance D between the four base stations forms a diagonal line Ak13 D Ak24 A quarter of the sum of D Ak The accuracy P of the multi-point localization results is obtained by comparison. mult The calculation formula is: （4） (5) (6) (7) From the formula, we can see that 0 ≤ P mult ≤ 1, which matches the description of accuracy; S06: The final accuracy P based on the multi-point positioning results mult Perform multi-point positioning coordinates L mult and inertial navigation coordinates L navi The fusion yields the final positioning result L. end The calculation formula is: (8)。

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