A ground target positioning method and device based on unmanned aerial vehicle

Abstract

The present invention relates to the field of positioning technology, and specifically to a method and device for ground target positioning based on an unmanned aerial vehicle. The present application utilizes an unobstructed unmanned aerial vehicle to collect positioning information of multiple waypoints, and performs distance measurement between the unmanned aerial vehicle and the ground target. Thus, the multiple waypoint data of the unmanned aerial vehicle replace the base station, which can not only avoid interference with the satellite positioning signal of the ground target, but also eliminate the need to establish a base station. The present application screens the waypoints based on flight stability and signal stability to obtain target waypoints with accurate measurement data. The measured distance and measured coordinates of the target waypoints are used, and the initial value of the ground target is calculated in combination with the least squares method, and then the optimal solution is iteratively calculated in combination with the Gauss-Newton hybrid algorithm. The optimal solution is further optimized using the actual distance and measured distance corresponding to the optimal solution, so that the positioning result in the present application is accurate and reliable. The present application can provide more applicable, accurate and reliable positioning results for field workers.

Description

Technical Field

[0001] The present invention relates to the field of positioning technology, and specifically to a ground target positioning method and device based on an unmanned aerial vehicle. Background Art

[0002] Positioning in field operations plays a key role in many aspects. For example, in a field environment, accurate positioning can ensure that operators know where they are, so as to avoid getting lost or entering dangerous areas. In emergency situations, such as natural disasters, wild animal attacks or injuries, precise positioning can quickly notify rescue teams, improve rescue efficiency, and reduce accident risks.

[0003] For the positioning of ground targets in field operations, satellite positioning and ranging positioning are generally used in the prior art. Among them, ranging positioning relies on ground base stations and has high costs. In some environments, the satellite positioning signals of ground targets are easily interfered. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a ground target positioning method and device based on an unmanned aerial vehicle to solve the problems in the background technology.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A ground target positioning method based on an unmanned aerial vehicle of the present invention comprises the following steps:

[0007] Obtain the measured coordinates of multiple waypoints when the drone flies along a preset route, the measured distances between multiple waypoints and ground targets, the flight attitude characteristics of multiple waypoints, and the ranging signal strength of multiple waypoints;

[0008] Determine the flight stability of the UAV based on the flight attitude characteristics of multiple waypoints, and determine the ranging signal stability of the UAV based on the ranging signal strength of multiple waypoints; eliminate the part whose flight stability is lower than a preset first threshold, and eliminate the part whose ranging signal stability is lower than a preset second threshold, to obtain the target waypoint;

[0009] Based on the measured coordinates and measured distances of multiple target waypoints, the initial position value of the ground target is calculated in combination with the least squares method; the initial value is iteratively optimized using the Gauss-Newton hybrid method to obtain the optimal solution for the position of the ground target;

[0010] The optimal solution for the position of the ground target is used to calculate the actual distance between the ground target and multiple target waypoints, and the optimal solution for the position of the ground target is optimized based on the actual distance and the measured distance to obtain the positioning information of the ground target.

[0011] In an embodiment of the present application, optimizing the optimal solution for the position of the ground target based on the actual distance and the measured distance to obtain the positioning information of the ground target includes:

[0012] Calculate the distance difference between the actual distance of each target waypoint and the ground target and the measured distance;

[0013] The target waypoints whose distance difference is greater than the preset third threshold are regarded as out-of-difference points, and the maximum out-of-difference point is eliminated to update the target waypoints;

[0014] Determining whether there is a steady-state error between the actual distance and the measured distance based on the multiple distance difference values, and when there is a steady-state error, compensating the measured distances of the multiple target waypoints based on the steady-state error;

[0015] Return to the measured coordinates and measured distances based on multiple target waypoints, and calculate the initial position value of the ground target in combination with the least squares method; until there is no target waypoint with a difference greater than a preset third threshold, and obtain the positioning information of the ground target.

[0016] In one embodiment of the present application, the flight attitude characteristics include accelerations on multiple axes. , is the waypoint number, is the axis number, wherein the flight stability of the UAV is determined based on the flight attitude characteristics of multiple waypoints, including:

[0017] Place the multiple waypoints on the axis The acceleration on Mapping into a first two-dimensional coordinate system, wherein the horizontal axis of the first two-dimensional coordinate system is the time axis, and the vertical axis of the first two-dimensional coordinate system is the acceleration axis;

[0018] A sliding window with a preset window width and sliding step size is used to slide along the time axis of the two-dimensional coordinate system, and the acceleration variance of the waypoints in the sliding window is calculated at each slide. ,in, is the sliding sequence number;

[0019] Based on the acceleration variance of the waypoints within the sliding window Calculate the axis of the drone exist Flight stability within the sector , ,in, is the first constant.

[0020] In one embodiment of the present application, determining the ranging signal stability of the drone based on the ranging signal strength of multiple waypoints includes:

[0021] Mapping the ranging signal strengths of the multiple waypoints into a second two-dimensional coordinate system, wherein the horizontal axis of the second two-dimensional coordinate system is a time axis, and the vertical axis of the second two-dimensional coordinate system is an intensity axis;

[0022] A sliding window with a preset window width is used to slide along the time axis of the two-dimensional coordinate system, and at each slide, the signal strength variance of the waypoints in the sliding window is calculated. ,in, is the sliding sequence number;

[0023] Based on the strength variance of the waypoints within the sliding window Computing drones in Ranging signal stability within the segment , ,in, is the second constant.

[0024] In one embodiment of the present application, judging whether there is a steady-state error between the actual distance and the measured distance based on a plurality of distance differences includes:

[0025] Calculate multiple distance differences The mean and variance of

[0026] When the target conditions are met at the same time, it is determined that there is a steady-state error between the actual distance and the measured distance, and the steady-state error is a number of distance differences. The average value of; otherwise it is determined that there is no steady-state error, wherein the target condition includes: multiple distance difference values The average value of is greater than a preset fourth threshold; multiple distance differences The variance of is less than or equal to a preset fifth threshold.

[0027] In one embodiment of the present application, based on the measured coordinates and measured distances of multiple target waypoints, the initial position value of the ground target is calculated by using the least square method, including:

[0028] Multiple distance formulas are constructed based on the measured coordinates and measured distances of multiple waypoints, where the mathematical expressions of the multiple distance formulas are:

[0029]

[0030] In the formula, is the first measured distance, For the The measured distance, Set the coordinates of the ground target. is the first measurement coordinate, For the measurement coordinates;

[0031] calculate and The difference between , , , , ,get ;

[0032] Deformation ,in,

[0033] , ,

[0034] The initial position value of the ground target is ,in, For the matrix The transposed matrix of .

[0035] In one embodiment of the present application, the Gauss-Newton hybrid method is used to iteratively optimize the initial value to obtain the optimal solution for the position of the ground target, including:

[0036] S1, constructing a nonlinear system of equations ,in, are the multiple distance formulas, is the ranging noise, is the solution of the nonlinear system of equations;

[0037] S2, taking the initial value as the current value ,in, is the current iteration number; and at the current value Carry out Taylor formula expansion on the nonlinear equations and retain the first-order terms to obtain ;

[0038] S3, let the current value The corresponding Jacobian matrix is , and calculate the residual vector of the current value , ;

[0039] S4, the residual vector With the preset convergence threshold For comparison, When As the optimal solution for the position of the ground target; otherwise, let , according to the formula renew , and return to step S3 until When , the optimal solution for the position of the ground target is obtained.

[0040] In an embodiment of the present application, it also includes: when the number of the target waypoints is less than a preset number threshold, adjusting the first threshold and the second threshold so that the number of the target waypoints is greater than the preset number threshold.

[0041] In one embodiment of the present application, the ground target and the drone are distanced via laser pulse signals.

[0042] The present application also provides a ground target positioning device based on a drone, comprising:

[0043] An acquisition module is used to obtain the measured coordinates of multiple waypoints when the UAV flies along a preset route, the measured distances between multiple waypoints and ground targets, the flight attitude characteristics of multiple waypoints, and the ranging signal strength of multiple waypoints;

[0044] A screening module is used to determine the flight stability of the UAV based on the flight attitude characteristics of multiple waypoints, and determine the ranging signal stability of the UAV based on the ranging signal strength of multiple waypoints; remove the part whose flight stability is lower than a preset first threshold, and remove the part whose ranging signal stability is lower than a preset second threshold, to obtain the target waypoint;

[0045] A positioning module is used to calculate the initial position value of the ground target based on the measured coordinates and measured distances of multiple target waypoints in combination with the least squares method; the initial value is iteratively optimized using the Gauss-Newton hybrid method to obtain the optimal solution for the position of the ground target;

[0046] The positioning optimization module is used to calculate the actual distance between the ground target and multiple target waypoints based on the optimal solution of the position of the ground target, and optimize the optimal solution of the position of the ground target based on the actual distance and the measured distance to obtain the positioning information of the ground target.

[0047] The beneficial effects of the present invention are as follows: a method and device for ground target positioning based on an unmanned aerial vehicle of the present invention, the present application utilizes an unobstructed unmanned aerial vehicle to collect the positioning information of multiple waypoints, and performs distance measurement between the unmanned aerial vehicle and the ground target. Thus, the multiple waypoint data of the unmanned aerial vehicle replace the base station, which can not only avoid interference with the satellite positioning signal of the ground target, but also eliminate the need to establish a base station. In addition, in order to avoid the accuracy of the measurement data of the unmanned aerial vehicle during flight, the present application screens the waypoints based on flight stability and signal stability to obtain the target waypoints with accurate measurement data. The measured distance and measured coordinates of the target waypoints are used, and the initial value of the ground target is calculated in combination with the least squares method, and then the optimal solution is iteratively calculated in combination with the Gauss-Newton hybrid algorithm. And finally, the optimal solution is further optimized using the actual distance and measured distance corresponding to the optimal solution, so that the positioning result in the present application is accurate and reliable. The present application can provide more applicable, accurate and reliable positioning results for field workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0049] Figure 1 This is an application scenario diagram in an embodiment of the present application;

[0050] Figure 2 is a flow chart of a ground target positioning method based on a drone shown in an embodiment of the present application;

[0051] Figure 3 This is a positioning flow chart based on the least squares method and the Gauss-Newton hybrid method in one embodiment of the present application;

[0052] Figure 4 A schematic diagram of the laser ranging axis and the visible light axis in this application;

[0053] Figure 5 is a schematic diagram of steady-state error compensation in an embodiment of the present application;

[0054] Figure 6 This is a positioning effect diagram in an embodiment of the present application;

[0055] Figure 7 It is a structural diagram of a ground target positioning device based on a drone shown in one embodiment of the present application. DETAILED DESCRIPTION

[0056] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0057] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show the layers related to the present invention rather than being drawn according to the number, shape and size of the layers in actual implementation. In actual implementation, the type, quantity and proportion of each layer may be changed arbitrarily, and the layer layout may also be more complicated.

[0058] In the following description, numerous details are discussed to provide a more thorough explanation of embodiments of the present invention; however, it is apparent to one skilled in the art that embodiments of the present invention may be practiced without these specific details.

[0059] Figure 1 This is an application scenario diagram in an embodiment of the present application, such as Figure 1 As shown, this application uses the positioning function of the drone to collect the positioning information of multiple waypoints on the drone route, such as (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), (x4, y4, z4). And use the ranging module of the drone pod to measure the distance with the ground target, such as the corresponding d1, d2, d3, d4. Using the above data, this application can perform positioning, and the specific process is as follows.

[0060] Figure 2 is a flow chart of a ground target positioning method based on a drone shown in an embodiment of the present application, such as Figure 1 As shown: A ground target positioning method based on a drone in this embodiment may include steps S210 to S240:

[0061] S210, obtaining the measured coordinates of multiple waypoints when the UAV flies along a preset route, the measured distances between the multiple waypoints and ground targets, the flight attitude characteristics of the multiple waypoints, and the ranging signal strengths of the multiple waypoints;

[0062] Among them, in the present application, the UAV flies according to a predetermined route (such as a straight track, or a circling track), and regularly collects and distributes control measurement coordinates and measurement distances through the built-in positioning module and optoelectronic pod. At the same time, the built-in acceleration sensor collects acceleration in the six-axis direction, and records the signal strength of the measurement pulse signal during measurement. The above data is positioned inside the UAV or sent to a ground target for positioning. S220, determine the flight stability of the UAV based on the flight attitude characteristics of multiple waypoints, and determine the ranging signal stability of the UAV based on the ranging signal strength of multiple waypoints; eliminate the part whose flight stability is lower than the preset first threshold, and eliminate the part whose ranging signal stability is lower than the preset second threshold, to obtain the target waypoint;

[0063] Since the positioning data and distance data relied on for positioning are collected by the drone during its movement, the drone’s attitude may be unstable during flight, causing the drone’s flight speed and attitude to change too much, resulting in deviations in the distance measurement data. It is also possible to encounter interference from fog, clouds, and ground obstructions at specific angles, resulting in unstable signals, which in turn causes deviations in the distance measurement data. Therefore, this application evaluates the reliability of the measurement data at each waypoint from the two aspects of flight stability and signal stability.

[0064] In one embodiment of the present application, the flight attitude characteristics include accelerations on multiple axes. , is the waypoint number, is the axis number, wherein the flight stability of the UAV is determined based on the flight attitude characteristics of multiple waypoints, including:

[0065] (1) Place the multiple waypoints on the axis The acceleration on Mapping into a first two-dimensional coordinate system, wherein the horizontal axis of the first two-dimensional coordinate system is the time axis, and the vertical axis of the first two-dimensional coordinate system is the acceleration axis;

[0066] (2) A sliding window with a preset window width and sliding step size is used to slide along the time axis of the two-dimensional coordinate system, and at each slide, the acceleration variance of the waypoints in the sliding window is calculated. ,in, is the sliding sequence number;

[0067] (3) Acceleration variance based on the waypoints in the sliding window Calculate the axis of the drone exist Flight stability within the sector , ,in, is the first constant.

[0068] This application maps the acceleration data of the drone corresponding to each waypoint in a two-dimensional coordinate system, and then uses a sliding window with fixed width and step size to extract multiple segments. In multiple segments, the acceleration variance on each axis is used to reflect the stability of the data. If the variance is large in a certain segment, it means that there is an unstable change in acceleration on one axis. This means that within this segment, the drone has active attitude changes, such as turning, rapid acceleration, rapid deceleration, rapid ascent, rapid descent and other flight actions. At this time, the collected data may be inaccurate. Therefore, using As the value of its stability, the sections with poor stability are removed to obtain waypoints with relatively stable flight attitude.

[0069] In one embodiment of the present application, determining the ranging signal stability of the drone based on the ranging signal strength of multiple waypoints includes:

[0070] (1) Mapping the ranging signal strengths of the multiple waypoints into a second two-dimensional coordinate system, wherein the horizontal axis of the second two-dimensional coordinate system is a time axis, and the vertical axis of the second two-dimensional coordinate system is an intensity axis;

[0071] (2) A sliding window with a preset window width is used to slide along the time axis of the two-dimensional coordinate system, and at each slide, the signal strength variance of the waypoints in the sliding window is calculated. ,in, is the sliding sequence number; (3) based on the strength variance of the waypoints in the sliding window Computing drones in Ranging signal stability within the segment , ,in, is the second constant.

[0072] Similarly, this application maps the intensity data of the ranging pulse signal of the drone corresponding to each waypoint in the two-dimensional coordinate system, and then uses a sliding window with fixed width and step size to extract multiple segments. The variance of the signal strength in each segment is calculated. If the variance is large, it means that the signal strength stability in the corresponding segment is poor. In this segment, the ranging signal emitted by the drone may be blocked by objects such as clouds and fog, and the collected data may be inaccurate. Therefore, using is used as the value of the segment stability, and the segments with poor stability are removed to obtain waypoints with relatively stable ranging signals.

[0073] In addition, the signal strength variance of the waypoints within the sliding window is calculated When , we also extract the mean , if the mean If it is significantly smaller than the set signal strength reference value, it means that the ranging signal is blocked or contaminated for a long time, and the waypoints in this section also need to be eliminated.

[0074] In the present application, at least 36 waypoints are required to execute the subsequent positioning algorithm. Therefore, when the number of the target waypoints is less than 36, the first threshold and the second threshold are adjusted so that the number of the target waypoints is greater than 36. After obtaining the required observation data, positioning is performed by the following method:

[0075] S230, based on the measured coordinates and measured distances of the plurality of target waypoints, and in combination with the least squares method, calculating the initial value of the position of the ground target; and iteratively optimizing the initial value using the Gauss-Newton hybrid method to obtain the optimal solution for the position of the ground target;

[0076] Figure 3 This is a positioning flow chart based on the least squares method and the Gauss-Newton hybrid method in an embodiment of the present application, such as Figure 3 As shown, this application will use the least squares method to calculate these observations to obtain the initial position estimate of the drone, including:

[0077] 1. Initial Solution Estimation

[0078] Assume that the coordinates of the target point to be estimated are , aircraft The known waypoint coordinates are The n distance measurement values ​​are ;

[0079] Multiple distance formulas are constructed based on the measured coordinates and measured distances of multiple waypoints, where the mathematical expressions of the multiple distance formulas are:

[0080]

[0081] In the formula, is the first measured distance, For the The measured distance, Set the coordinates of the ground target. is the first measurement coordinate, For the Measure coordinates; calculate and The difference between , , , , ,get ;

[0082] Deformation ,in,

[0083] , ,

[0084] The initial position value of the ground target is ,in, For the matrix The transposed matrix of .

[0085] 2. Optimal Solution Estimation

[0086] S1, constructing a nonlinear system of equations ,in, are the multiple distance formulas, is the ranging noise, is the solution of the nonlinear system of equations;

[0087] S2, taking the initial value as the current value ,in, is the current number of iterations, and the optimal solution is set to , so we need to make the residual vector The sum of squares minimum; at the current value Carry out Taylor formula expansion on the nonlinear equations and retain the first-order terms to obtain ;

[0088] S3, let the current value The corresponding Jacobian matrix is , and calculate the residual vector of the current value , ;

[0089] S4, perform convergence check, and convert the residual vector With the preset convergence threshold For comparison, When As the optimal solution for the position of the ground target; otherwise, let , according to the formula renew , and return to step S3 until When , the optimal solution for the position of the ground target is obtained.

[0090] In the above process, the initial solution of the least squares method is used as the initial estimate, which reduces the sensitivity of the Gauss-Newton method to the initial value and enables the algorithm to run stably under various conditions. ,The algorithm can effectively determine when to stop iterating, thereby saving computing resources and avoiding unnecessary calculations.

[0091] Improved convergence performance: By calculating the residual vector and Jacobian matrix in each iteration, the algorithm can converge to the optimal solution faster, improving computational efficiency.

[0092] S240, calculating the actual distance between the ground target and multiple target waypoints using the optimal solution for the position of the ground target, and optimizing the optimal solution for the position of the ground target based on the actual distance and the measured distance to obtain positioning information of the ground target.

[0093] In order to improve the robustness of the algorithm and further prevent the distortion of the pod laser ranging data due to meteorological conditions such as fog and clouds, that is, the laser bounces off the clouds and measures the wrong distance. This application also sets up the following optimization process to eliminate out-of-tolerance data, which can ensure the accuracy and reliability of the final solution, including:

[0094] S241, calculating the distance difference between the actual distance of each target waypoint and the ground target and the measured distance;

[0095] There are currently n observations, each of which consists of two parts: one is the coordinates of the i-th aircraft , and the second is the distance from the aircraft to the target point obtained by pod ranging ; First traverse the observation data: traverse from the first observation point to the nth observation point, and use the optimal solution to calculate the actual distance from each observation point to the target point.

[0096] S242, taking the target waypoints whose distance difference is greater than a preset third threshold as out-of-difference points, and removing the maximum out-of-difference point to update the target waypoint;

[0097] For each observation point, if the difference between the calculated actual distance and the measured distance is greater than 3.0 meters, it is considered as an out-of-tolerance and marked. Out-of-tolerance processing: After the traversal is completed, check whether there is an out-of-tolerance situation. If so, identify and eliminate the largest out-of-tolerance item.

[0098] S243, judging whether there is a steady-state error between the actual distance and the measured distance based on the multiple distance difference values, and if there is a steady-state error, compensating the measured distances of the multiple target waypoints based on the steady-state error;

[0099] Figure 4 Schematic diagram of the laser ranging axis and the visible light axis in this application, such as Figure 4As shown, the distance measurement calibration takes into account that the visible light axis of the pod is usually not completely aligned with the laser ranging axis, which may cause the measured distance value to be lower than the actual value, thereby introducing a measurement error. Especially when the aircraft is hovering for measurement, this error will appear in the elevation data. In order to reduce this system error, the present application also provides a steady-state error elimination method, specifically, based on multiple distance difference values, it is judged whether there is a steady-state error between the actual distance and the measured distance, including:

[0100] S2431, calculate multiple distance differences The mean and variance of

[0101] S2432: When the target conditions are met at the same time, it is determined that there is a steady-state error between the actual distance and the measured distance, and the steady-state error is a plurality of distance differences. The average value of; otherwise it is determined that there is no steady-state error, wherein the target condition includes: multiple distance difference values The average value of is greater than a preset fourth threshold; multiple distance differences The variance of is less than or equal to a preset fifth threshold.

[0102] In this application, if the error mean is large, the variance is small, and the stability is strong, then it is determined that there is a steady-state error. At this time, the steady-state error is used to compensate the measured distances of multiple target waypoints. In subsequent measurement activities, the original distance observation value provided by the pod is added to the compensation value to obtain the corrected distance observation value.

[0103] Through this calibration process, system errors can be effectively corrected and the accuracy of ranging data can be improved, thereby ensuring the accuracy of subsequent positioning and navigation tasks. Figure 5 Schematic diagram of steady-state error compensation in an embodiment of the present application. Figure 5 As shown, the actual distance (green) and the pod observation distance (red), the calculated compensation value is 2.2 meters.

[0104] S244, return to the measurement coordinates and measurement distances based on multiple target waypoints, and calculate the initial position value of the ground target in combination with the least squares method; until there is no target waypoint whose difference is greater than the preset third threshold, and the positioning information of the ground target is obtained.

[0105] After eliminating the out-of-tolerance items and steady-state errors, return to step S230, reposition and optimize until all observation items are free of out-of-tolerance conditions, at which point this settlement ends. If out-of-tolerance conditions continue to occur, continue to eliminate the largest out-of-tolerance item until the number of observations drops below 4. If this condition is met, it is determined that there is no solution, and the corresponding information is output.

[0106] Figure 6 This is a positioning effect diagram in an embodiment of the present application, such as Figure 6 As shown, the positioning results measured by this application have a small deviation from the actual target point position in the center, and the positioning accuracy is good.

[0107] The present invention discloses a method for locating ground targets based on drones. The present application utilizes unobstructed drones to collect the positioning information of multiple waypoints, and measures the distance between the drone and the ground targets. Thus, the multiple waypoint data of the drone replace the base station, which can avoid interference with the satellite positioning signal of the ground target and eliminate the need to establish a base station. In addition, in order to avoid the accuracy of the measurement data of the drone during flight, the present application selects the waypoints based on flight stability and signal stability to obtain the target waypoints with accurate measurement data. The measured distance and measured coordinates of the target waypoints are used, and the initial value of the ground target is calculated in combination with the least squares method, and then the optimal solution is iteratively calculated in combination with the Gauss-Newton hybrid algorithm. Finally, the optimal solution is further optimized using the actual distance and measured distance corresponding to the optimal solution, so that the positioning result in the present application is accurate and reliable. The present application can provide more applicable, accurate and reliable positioning results for field workers.

[0108] like Figure 7 As shown, the present application also provides a ground target positioning device based on a drone, comprising:

[0109] An acquisition module is used to obtain the measured coordinates of multiple waypoints when the UAV flies along a preset route, the measured distances between multiple waypoints and ground targets, the flight attitude characteristics of multiple waypoints, and the ranging signal strength of multiple waypoints;

[0110] A screening module is used to determine the flight stability of the UAV based on the flight attitude characteristics of multiple waypoints, and determine the ranging signal stability of the UAV based on the ranging signal strength of multiple waypoints; remove the part whose flight stability is lower than a preset first threshold, and remove the part whose ranging signal stability is lower than a preset second threshold, to obtain the target waypoint;

[0111] A positioning module is used to calculate the initial position value of the ground target based on the measured coordinates and measured distances of multiple target waypoints in combination with the least squares method; the initial value is iteratively optimized using the Gauss-Newton hybrid method to obtain the optimal solution for the position of the ground target;

[0112] The positioning optimization module is used to calculate the actual distance between the ground target and multiple target waypoints based on the optimal solution of the position of the ground target, and optimize the optimal solution of the position of the ground target based on the actual distance and the measured distance to obtain the positioning information of the ground target.

[0113] The present invention discloses a ground target positioning device based on an unmanned aerial vehicle. The present application utilizes an unobstructed unmanned aerial vehicle to collect the positioning information of multiple waypoints, and performs distance measurement between the unmanned aerial vehicle and the ground target. Thus, the multiple waypoint data of the unmanned aerial vehicle replace the base station, which can avoid interference with the satellite positioning signal of the ground target and eliminate the need to establish a base station. In addition, in order to avoid the accuracy of the measurement data of the unmanned aerial vehicle during flight, the present application selects the waypoints based on flight stability and signal stability to obtain the target waypoints with accurate measurement data. The measured distance and measured coordinates of the target waypoints are used, and the initial value of the ground target is calculated in combination with the least squares method, and then the optimal solution is iteratively calculated in combination with the Gauss-Newton hybrid algorithm. Finally, the optimal solution is further optimized using the actual distance and measured distance corresponding to the optimal solution, so that the positioning result in the present application is accurate and reliable. The present application can provide more applicable, accurate and reliable positioning results for field workers.

[0114] This embodiment further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, any one of the methods in this embodiment is implemented, wherein the method is the execution logic of this system.

[0115] This embodiment also provides an electronic terminal, including: a processor and a memory;

[0116] The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes any one of the methods in this embodiment.

[0117] The computer-readable storage medium in this embodiment can be understood by ordinary technicians in this field: all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

[0118] The electronic terminal provided in this embodiment includes a processor, a memory, a transceiver and a communication interface. The memory and the communication interface are connected to the processor and the transceiver and complete communication with each other. The memory is used to store computer programs, the communication interface is used to communicate, and the processor and the transceiver are used to run computer programs so that the electronic terminal executes each step of the above method.

[0119] In this embodiment, the memory may include a random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0120] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0121] In the above-mentioned embodiments, although the present invention has been described in conjunction with the specific embodiments of the present invention, many replacements, modifications and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description. The embodiments of the present invention are intended to cover all such replacements, modifications and variations falling within the broad scope of the appended claims.

[0122] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A ground target positioning method based on an unmanned aerial vehicle, characterized in that: include: Obtain the measured coordinates of multiple waypoints when the drone flies along a preset route, the measured distances between multiple waypoints and ground targets, the flight attitude characteristics of multiple waypoints, and the ranging signal strength of multiple waypoints; Determine the flight stability of the UAV based on the flight attitude characteristics of multiple waypoints, and determine the ranging signal stability of the UAV based on the ranging signal strength of multiple waypoints; Eliminate the part whose flight stability is lower than a preset first threshold, and eliminate the part whose ranging signal stability is lower than a preset second threshold, to obtain the target waypoint; Based on the measured coordinates and measured distances of multiple target waypoints, the initial position value of the ground target is calculated in combination with the least squares method; The Gauss-Newton hybrid method is used to iteratively optimize the initial value to obtain the optimal solution for the position of the ground target; The method comprises: calculating the actual distance between the ground target and a plurality of target waypoints based on the optimal solution of the position of the ground target, optimizing the optimal solution of the position of the ground target based on the actual distance and the measured distance to obtain the positioning information of the ground target, and optimizing the optimal solution of the position of the ground target based on the actual distance and the measured distance to obtain the positioning information of the ground target, including: calculating the distance difference between the actual distance between each target waypoint and the ground target and the measured distance; The target waypoints whose distance difference is greater than the preset third threshold are regarded as out-of-difference points, and the maximum out-of-difference point is eliminated to update the target waypoints; Based on multiple distance differences, it is judged whether there is a steady-state error between the actual distance and the measured distance. When there is a steady-state error, the measured distances of multiple target waypoints are compensated based on the steady-state error; returning to the measured coordinates and measured distances based on the multiple target waypoints, and calculating the initial position value of the ground target in combination with the least squares method; until there is no target waypoint with a difference greater than a preset third threshold, and the positioning information of the ground target is obtained; based on multiple distance differences, it is judged whether there is a steady-state error between the actual distance and the measured distance, including: calculating multiple distance differences When the target conditions are met at the same time, it is determined that there is a steady-state error between the actual distance and the measured distance, and the steady-state error is a number of distance differences. The average value of; otherwise it is determined that there is no steady-state error, wherein the target condition includes: multiple distance difference values The average value of is greater than a preset fourth threshold; multiple distance differences The variance of is less than or equal to a preset fifth threshold.

2. A ground target positioning method based on an unmanned aerial vehicle according to claim 1, characterized in that: The flight attitude characteristics include acceleration on multiple axes , is the waypoint number, is the axis number, wherein the flight stability of the UAV is determined based on the flight attitude characteristics of multiple waypoints, including: Place the multiple waypoints on the axis The acceleration on Mapping into a first two-dimensional coordinate system, wherein the horizontal axis of the first two-dimensional coordinate system is the time axis, and the vertical axis of the first two-dimensional coordinate system is the acceleration axis; A sliding window with a preset window width and sliding step size is used to slide along the time axis of the two-dimensional coordinate system, and the acceleration variance of the waypoints in the sliding window is calculated at each slide. ,in, is the sliding sequence number; Based on the acceleration variance of the waypoints within the sliding window Calculate the axis of the drone exist Flight stability within the sector , ,in, is the first constant.

3. The method for locating a ground target based on an unmanned aerial vehicle according to claim 1, characterized in that: Determine the stability of the drone's ranging signal based on the ranging signal strength of multiple waypoints, including: Mapping the ranging signal strengths of the multiple waypoints into a second two-dimensional coordinate system, wherein the horizontal axis of the second two-dimensional coordinate system is a time axis, and the vertical axis of the second two-dimensional coordinate system is an intensity axis; A sliding window with a preset window width is used to slide along the time axis of the two-dimensional coordinate system, and at each slide, the signal strength variance of the waypoints in the sliding window is calculated. ,in, is the sliding sequence number; Based on the strength variance of the waypoints within the sliding window Computing drones in Ranging signal stability within the segment , ,in, is the second constant.

4. A ground target positioning method based on an unmanned aerial vehicle according to claim 1, characterized in that: Based on the measured coordinates and measured distances of multiple target waypoints, the initial position value of the ground target is calculated by using the least square method, including: Multiple distance formulas are constructed based on the measured coordinates and measured distances of multiple waypoints, where the mathematical expressions of the multiple distance formulas are: In the formula, is the first measured distance, For the The measured distance, Set the coordinates of the ground target. is the first measurement coordinate, For the measurement coordinates; calculate and The difference between , , , , ,get ; Deformation ,in, , , The initial position value of the ground target is ,in, For the matrix The transposed matrix of .

5. A ground target positioning method based on an unmanned aerial vehicle according to claim 4, characterized in that: The Gauss-Newton hybrid method is used to iteratively optimize the initial value to obtain the optimal solution for the position of the ground target, including: S1, constructing a nonlinear system of equations ,in, are the multiple distance formulas, is the ranging noise, is the solution of the nonlinear system of equations; S2, taking the initial value as the current value ,in, is the current iteration number; and at the current value Carry out Taylor formula expansion on the nonlinear equations and retain the first-order terms to obtain ; S3, let the current value The corresponding Jacobian matrix is , and calculate the residual vector of the current value , ; S4, the residual vector With the preset convergence threshold For comparison, When As the optimal solution for the position of the ground target; otherwise, let , according to the formula renew , and return to step S3 until When , the optimal solution for the position of the ground target is obtained.

6. A ground target positioning method based on an unmanned aerial vehicle according to claim 1, characterized in that: Also includes: When the number of the target waypoints is less than a preset number threshold, the first threshold and the second threshold are adjusted so that the number of the target waypoints is greater than the preset number threshold.

7. The method for locating a ground target based on an unmanned aerial vehicle according to claim 1, characterized in that: The ground target and the UAV are distanced via laser pulse signals.

8. A ground target positioning device based on an unmanned aerial vehicle, characterized in that: include: An acquisition module is used to obtain the measured coordinates of multiple waypoints when the UAV flies along a preset route, the measured distances between multiple waypoints and ground targets, the flight attitude characteristics of multiple waypoints, and the ranging signal strength of multiple waypoints; A screening module, used to determine the flight stability of the UAV based on the flight attitude characteristics of multiple waypoints, and to determine the ranging signal stability of the UAV based on the ranging signal strength of the multiple waypoints; Eliminate the part whose flight stability is lower than a preset first threshold, and eliminate the part whose ranging signal stability is lower than a preset second threshold, to obtain the target waypoint; A positioning module, used to calculate the initial position value of the ground target based on the measured coordinates and measured distances of multiple target waypoints and in combination with the least squares method; The Gauss-Newton hybrid method is used to iteratively optimize the initial value to obtain the optimal solution for the position of the ground target; A positioning optimization module, used to calculate the actual distance between the ground target and multiple target waypoints based on the optimal solution of the position of the ground target, and optimize the optimal solution of the position of the ground target based on the actual distance and the measured distance to obtain the positioning information of the ground target, and optimize the optimal solution of the position of the ground target based on the actual distance and the measured distance to obtain the positioning information of the ground target, including: calculating the distance difference between the actual distance and the measured distance between each target waypoint and the ground target; The target waypoints whose distance difference is greater than the preset third threshold are regarded as out-of-difference points, and the maximum out-of-difference point is eliminated to update the target waypoints; Based on multiple distance differences, it is judged whether there is a steady-state error between the actual distance and the measured distance. When there is a steady-state error, the measured distances of multiple target waypoints are compensated based on the steady-state error; returning to the measured coordinates and measured distances based on the multiple target waypoints, and calculating the initial position value of the ground target in combination with the least squares method; until there is no target waypoint with a difference greater than a preset third threshold, and the positioning information of the ground target is obtained; based on multiple distance differences, it is judged whether there is a steady-state error between the actual distance and the measured distance, including: calculating multiple distance differences When the target conditions are met at the same time, it is determined that there is a steady-state error between the actual distance and the measured distance, and the steady-state error is a number of distance differences. The average value of; otherwise it is determined that there is no steady-state error, wherein the target condition includes: multiple distance difference values The average value of is greater than a preset fourth threshold; multiple distance differences The variance of is less than or equal to a preset fifth threshold.

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