Two-axis two-frame photoelectric device over-the-top tracking control method and system, storage medium

Abstract

The application provides a two-axis two-frame photoelectric device over-the-top tracking control method and system, and a storage medium. The two-axis two-frame photoelectric device over-the-top tracking control method comprises the following steps: obtaining the azimuth angle, the pitch angle, the flying height of an airplane and the initial position of a target of a two-axis two-frame photoelectric device in a tracking state through a three-axis gyroscope; determining the target position and target speed information according to the azimuth angle, the pitch angle and the flying height; calculating the over-the-top pitch angle when the target enters the over-the-top tracking state in real time through dichotomy; judging whether the absolute value of the pitch angle is greater than or equal to the over-the-top pitch angle; if yes, calculating the over-the-top azimuth angle and the maximum rotating speed required by the shaft system position ring, and performing shaft system position control according to the over-the-top azimuth angle and the maximum rotating speed; and if no, performing gyroscope tracking ring control. Through the technical scheme, the boresight error angle generated by the two-axis two-frame photoelectric device in the over-the-top tracking can be effectively reduced, and the target can be ensured to be in the field of view to the maximum extent.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of motion control of optoelectronic equipment, and particularly relates to a two-axis two-frame optoelectronic equipment over-the-top tracking control method and system and a storage medium. BACKGROUND

[0002] The optoelectronic equipment tracks the target by taking the deviation between the target and the optical axis as the input of the azimuth and elevation angles of the servo control for target tracking. However, due to the limitation of the mechanical structure of the two-axis two-frame equipment, the azimuth angle velocity of the optical axis and the angle velocity of the azimuth axis have a secant projection relationship, which leads to a very high requirement for the azimuth rotation speed of the equipment when the target passes or approaches directly below the aircraft. When the requirement for the azimuth rotation speed is greater than the highest azimuth rotation speed that the equipment can reach, the target will be out of the optical axis or even out of the field of view, resulting in the loss of tracking the target. In the prior art, the off-axis tracking technology can reduce the requirement for the azimuth rotation speed during over-the-top tracking, but the gain of this over-the-top tracking strategy is very small when the optoelectronic equipment tracks the target in a small field of view. SUMMARY

[0003] The application aims to solve or improve the above technical problems.

[0004] To this end, the application provides a two-axis two-frame optoelectronic equipment over-the-top tracking control method.

[0005] The application also provides a two-axis two-frame optoelectronic equipment over-the-top tracking control system.

[0006] The application also provides a two-axis two-frame optoelectronic equipment over-the-top tracking control system.

[0007] The application also provides a readable storage medium.

[0008] To achieve the above purpose, the application provides a two-axis two-frame optoelectronic equipment over-the-top tracking control method, which comprises the following steps: acquiring the azimuth angle, the elevation angle, the flying height of the aircraft and the initial position of the target of the two-axis two-frame optoelectronic equipment in the tracking state through a three-axis gyroscope; determining the target position and target speed information according to the azimuth angle, the elevation angle and the flying height; calculating the over-the-top elevation angle when the target enters the over-the-top tracking state in real time through the dichotomy method; judging whether the absolute value of the elevation angle is greater than or equal to the over-the-top elevation angle; if yes, calculating the over-the-top azimuth angle that the shaft system position ring needs to rotate and the maximum rotation speed of the shaft system speed, and performing shaft system position control according to the over-the-top azimuth angle and the maximum rotation speed; and if no, performing gyro tracking ring control.

[0009] According to the two-axis two-frame photoelectric device over-the-top tracking control method provided in the application, first, the azimuth angle, the pitch angle, the flying height of the aircraft and the initial position of the target of the two-axis two-frame photoelectric device in the tracking state are obtained by a three-axis gyroscope. The three-axis gyroscope is used to solve the angular velocity in the azimuth direction by relying on the angular velocity sensitivity of the azimuth axis and the roll axis, and the device has the function of over-the-top stability. Then, the target position and target speed information are determined according to the azimuth angle, the pitch angle and the flying height. The over-the-top pitch angle when the target enters the over-the-top tracking state is calculated in real time by the dichotomy method. The dichotomy numerical solution has the characteristics of fast convergence speed, less iteration times and high operation precision. The current computing power level of the embedded device chip can fully meet the operation demand of the dichotomy method. Then, it is judged whether the absolute value of the pitch angle is greater than or equal to the over-the-top pitch angle. If yes, the over-the-top azimuth angle that the shaft system position ring needs to rotate and the maximum rotating speed of the shaft system speed are calculated, and the shaft system position control is performed according to the over-the-top azimuth angle and the maximum rotating speed. If not, the gyro tracking loop control is performed. The dichotomy method is used to solve the transcendental equation generated by the geometric relationship in the over-the-top tracking to find the optimal over-the-top pitch angle, and the azimuth rotating speed of the device is fully utilized to minimize the maximum deviation of the target from the optical axis in the image, thereby maximizing the guarantee that the target can be within the field of view during the over-the-top tracking.

[0010] In addition, the technical solutions provided in the application can also have the following additional technical features:

[0011] In some technical solutions, the over-the-top pitch angle when the target enters the over-the-top tracking state is calculated in real time by the dichotomy method, including: when the target enters the over-the-top circle region with the aircraft directly below as the center, the radius of the over-the-top circle is calculated by the dichotomy method; and the over-the-top pitch angle is calculated according to the radius of the over-the-top circle and the flying height of the aircraft.

[0012] In the technical solution, the over-the-top pitch angle when the target enters the over-the-top tracking state is calculated in real time by the dichotomy method, specifically: first, when the target enters the over-the-top circle region with the aircraft directly below as the center, the radius of the over-the-top circle is calculated by the dichotomy method. Then, the over-the-top pitch angle is calculated according to the radius of the over-the-top circle and the flying height of the aircraft. It can be understood that, in order to fully utilize the azimuth rotating speed, over-the-top at the maximum azimuth speed is the optimal choice for the tracking precision of the program guidance method, that is, when the over-the-top azimuth speed is equal to the maximum rotating speed of the shaft system speed, the over-the-top pitch angle and the radius of the over-the-top circle calculated are the optimal over-the-top pitch angle and the radius of the over-the-top circle. The dichotomy numerical solution has the characteristics of fast convergence speed, less iteration times and high operation precision. The current computing power level of the embedded device chip can fully meet the operation demand of the dichotomy method.

[0013] In some embodiments, the maximum rotation speed of the azimuth angle of the over-the-top position ring and the shaft speed is calculated, comprising: obtaining the over-the-top azimuth angle and the over-the-top tracking time according to the over-the-top pitch angle; obtaining the over-the-top azimuth speed according to the over-the-top azimuth angle and the over-the-top tracking time, and obtaining the maximum rotation speed of the shaft speed according to the over-the-top azimuth speed.

[0014] In the technical solution, the maximum rotation speed of the azimuth angle of the over-the-top position ring and the shaft speed is calculated, specifically, the over-the-top azimuth angle and the over-the-top tracking time are obtained according to the over-the-top pitch angle. Then, the over-the-top azimuth speed is obtained according to the over-the-top azimuth angle and the over-the-top tracking time, and the calculated over-the-top azimuth speed is equal to the maximum rotation speed of the azimuth angle of the device.

[0015] In some embodiments, the calculation formula of the over-the-top pitch angle is:

[0016]

[0017] wherein, θ Eover is the over-the-top pitch angle, R is the radius of the over-the-top circle, and h is the flying height of the aircraft.

[0018] In the technical solution, the over-the-top pitch angle can be calculated according to the radius of the over-the-top circle and the flying height of the aircraft.

[0019] In some embodiments, the calculation formula of the over-the-top tracking time is:

[0020]

[0021] wherein, t over is the over-the-top tracking time, (x0, y0) is the initial position of the target, v x is the speed of the target along the ox direction of the coordinate system, v y is the speed of the target along the oy direction of the coordinate system, and R is the radius of the over-the-top circle.

[0022] In the technical solution, the over-the-top tracking time can be obtained according to the initial position of the target, the speed of the target along the ox direction of the coordinate system, the speed of the target along the oy direction of the coordinate system, and the radius of the over-the-top circle.

[0023] In some embodiments, the calculation formula of the over-the-top azimuth angle is:

[0024]

[0025] wherein, t over is the over-the-top tracking time, θ Aover is the over-the-top azimuth angle, v x is the speed of the target along the ox direction of the coordinate system, and v yis the distance between points A and B.

[0026] In the technical solution, the over-the-top azimuth angle can be obtained by the over-the-top tracking time, the speed of the target along the ox direction of the coordinate system, the speed of the target along the oy direction of the coordinate system, and the radius of the over-the-top circle.

[0027] In some technical solutions, optionally, the calculation formula of the over-the-top azimuth speed is:

[0028] v Aover = θ Aover / t over ;

[0029] wherein, t over is the over-the-top tracking time, θ Aover is the over-the-top azimuth angle, and v Aover is the over-the-top azimuth speed.

[0030] In the technical solution, the over-the-top azimuth speed can be obtained according to the over-the-top azimuth angle and the over-the-top tracking time.

[0031] Embodiments of the present application provide an over-the-top tracking control system of a two-axis two-frame photoelectric device, comprising: an acquisition module configured to acquire, by a three-axis gyroscope, an azimuth angle, a pitch angle, a flying height of an airplane, and an initial position of a target of the two-axis two-frame photoelectric device in a tracking state; a determination module configured to determine target position and target speed information according to the azimuth angle, the pitch angle, and the flying height; a real-time calculation module configured to calculate, by a dichotomy method, an over-the-top pitch angle when the target enters an over-the-top tracking state; and a control module configured to judge whether an absolute value of the pitch angle is greater than or equal to the over-the-top pitch angle; if yes, calculate an over-the-top azimuth angle that a position ring of an axis system needs to rotate and a maximum rotating speed of an axis system speed, and perform axis system position control according to the over-the-top azimuth angle and the maximum rotating speed; and if no, perform a gyro tracking loop control.

[0032] The two-axis two-frame photoelectric device over-the-top tracking control system provided in the application comprises an acquisition module, a determination module, a real-time calculation module and a control module. The acquisition module is configured to acquire the azimuth angle, the pitch angle, the flying height of the aircraft and the initial position of the target of the two-axis two-frame photoelectric device in the tracking state through a three-axis gyroscope. The determination module is configured to determine the target position and the target speed information according to the azimuth angle, the pitch angle and the flying height. The real-time calculation module is configured to calculate the over-the-top pitch angle when the target enters the over-the-top tracking state in real time through the bisection method. The control module is configured to determine whether the absolute value of the pitch angle is greater than or equal to the over-the-top pitch angle. If yes, the over-the-top azimuth angle that the shaft system position ring needs to rotate and the maximum rotating speed of the shaft system speed are calculated, and the shaft system position control is performed according to the over-the-top azimuth angle and the maximum rotating speed. If no, the gyro tracking ring control is performed. The optimal over-the-top pitch angle is found by solving the transcendental equation generated by the geometric relationship in the over-the-top tracking through the bisection method, the azimuth rotating speed of the device is fully utilized to minimize the maximum deviation of the target from the visual axis in the image, and the target can be ensured to be within the field of view in the process of over-the-top tracking.

[0033] The embodiment of the application provides a two-axis two-frame photoelectric device over-the-top tracking control system, comprising a memory and a processor, wherein the memory stores programs or instructions executable on the processor, and the processor implements the two-axis two-frame photoelectric device over-the-top tracking control method of any one of the technical solutions in the first aspect, so that the technical effects of any one of the technical solutions in the first aspect are achieved, and details are not repeated here.

[0034] The embodiment of the application provides a readable storage medium, which stores programs or instructions, and the programs or instructions are executed by a processor to implement the steps of the two-axis two-frame photoelectric device over-the-top tracking control method of any one of the technical solutions in the first aspect, so that the technical effects of any one of the technical solutions in the first aspect are achieved, and details are not repeated here.

[0035] Additional aspects and advantages of the application will become apparent in the light of the following description and by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0036] The above and / or additional aspects and advantages of the application will become apparent and be readily understood by considering the following detailed description, from which the embodiments emerge, in connection with the accompanying drawings, wherein:

[0037] Figure 1 The step flowchart of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the application;

[0038] Figure 2 The step flowchart of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the application;

[0039] Figure 3 The flow chart of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0040] Figure 4 The structural schematic diagram of the system for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0041] Figure 5 The structural schematic diagram of the system for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0042] Figure 6 The schematic diagram of the spatial rectangular coordinate system of the axis system of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0043] Figure 7 The three-dimensional diagram corresponding to the program guiding method of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0044] Figure 8 The two-dimensional diagram of the over-the-top circle in the xoy plane projection of the program guiding method of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0045] Figure 9 The schematic diagram of the linearization processing of the sin function of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0046] Figure 10 The schematic diagram of the Matlab program code and the running result of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0047] Figure 11 The schematic diagram of the solving of the boresight error angle of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0048] Figure 12 The schematic diagram of the over-the-top tracking boresight error angle curve of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application without tracking measures;

[0049] Figure 13 The schematic diagram of the over-the-top tracking boresight error angle curve of the program guiding method of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application;

[0050] Figure 14 The schematic diagram of the azimuth and pitch miss distance curve and the solving of the tracking precision of the tracking experiment of the method for controlling the over-the-top tracking of the two-axis two-frame optoelectronic device according to an embodiment of the present application without over-the-top tracking strategy;

[0051] Figure 15The azimuth, elevation off-target amount curve and tracking error calculation diagram of the program guide method of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the present application;

[0052] Figure 16 The azimuth, elevation off-target amount curve and tracking error calculation diagram of the program guide method of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the present application;

[0053] Figure 17 The azimuth, elevation off-target amount curve and tracking error calculation diagram of the program guide method of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the present application;

[0054] Figure 18 The azimuth, elevation off-target amount curve and tracking error calculation diagram of the program guide method of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the present application;

[0055] Figure 19 The azimuth, elevation off-target amount curve and tracking error calculation diagram of the program guide method of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the present application;

[0056] Figure 20 The azimuth, elevation off-target amount curve and tracking error calculation diagram of the program guide method of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the present application;

[0057] Figure 21 The azimuth, elevation off-target amount curve and tracking error calculation diagram of the program guide method of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the present application;

[0058] The azimuth, elevation off-target amount curve and tracking error calculation diagram of the program guide method of the two-axis two-frame photoelectric device over-the-top tracking control method of one embodiment of the present application; Figure 4 And Figure 5 The correspondence between the reference signs and the component names in

[0059] 10: two-axis two-frame photoelectric device over-the-top tracking control system; 110: acquisition module; 120: determination module; 130: real-time calculation module; 140: control module; 20: two-axis two-frame photoelectric device over-the-top tracking control system; 300: storage; 400: processor. DETAILED DESCRIPTION

[0060] In order to make the purposes, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0061] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Figures 1 to 21 The two-axis two-frame optoelectronic device over-the-top tracking control method and system, and the storage medium are described.

[0062] As shown in the first aspect of the present application, the embodiments provide a two-axis two-frame optoelectronic device over-the-top tracking control method, comprising the following steps: Figure 1 Step S102: acquiring the azimuth angle, the pitch angle, the flying height of the aircraft and the initial position of the target of the two-axis two-frame optoelectronic device in the tracking state through a three-axis gyroscope;

[0063] Step S104: determining the target position and the target speed information according to the azimuth angle, the pitch angle and the flying height;

[0064] Step S106: calculating the over-the-top pitch angle when the target enters the over-the-top tracking state in real time through the dichotomy method;

[0065] Step S108: judging whether the absolute value of the pitch angle is greater than or equal to the over-the-top pitch angle;

[0066] Step S110: if yes, calculating the over-the-top azimuth angle that the shafting position ring needs to rotate and the maximum rotating speed of the shafting speed, and performing the shafting position control according to the over-the-top azimuth angle and the maximum rotating speed;

[0067] Step S112: if no, performing the gyro tracking loop control.

[0068]

[0069] ​According to the two-axis two-frame photoelectric device over-the-top tracking control method provided in the embodiment, firstly, the azimuth angle, the pitch angle, the flying height of the aircraft and the initial position of the target of the two-axis two-frame photoelectric device in the tracking state are obtained through the three-axis gyroscope. The three-axis gyroscope is adopted to solve the angular velocity in the azimuth direction by relying on the angular velocity sensitive to the azimuth axis and the roll axis of the gyroscope, and the device has the function of over-the-top stability. Then, the target position and target speed information are determined according to the azimuth angle, the pitch angle and the flying height. The over-the-top pitch angle when the target enters the over-the-top tracking state is calculated in real time by the dichotomy method. The dichotomy numerical solution has the characteristics of fast convergence speed, less iteration times and high operation precision. The current computing power level of the embedded device chip can fully meet the operation demand of the dichotomy method. Then, it is judged whether the absolute value of the pitch angle is greater than or equal to the over-the-top pitch angle. If yes, the over-the-top azimuth angle that the shaft system position ring needs to rotate and the maximum rotating speed of the shaft system speed are calculated, and the shaft system position control is performed according to the over-the-top azimuth angle and the maximum rotating speed. If no, the gyro tracking loop control is performed. The dichotomy method is used to solve the transcendental equation generated by the geometric relationship in the over-the-top tracking to find the optimal over-the-top pitch angle, and the azimuth rotating speed of the device is fully utilized to minimize the maximum deviation of the target from the optical axis in the image, thereby maximizing the guarantee that the target can be within the field of view in the over-the-top tracking process.

[0070] As shown in the two-axis two-frame photoelectric device over-the-top tracking control method according to an embodiment of the present application, Figure 2 the dichotomy method is used to calculate the over-the-top pitch angle when the target enters the over-the-top tracking state in real time, including the following steps:

[0071] Step S202: when the target enters the over-the-top circle region with the center being directly below the carrier, the radius of the over-the-top circle is calculated by the dichotomy method.

[0072] Step S204: the over-the-top pitch angle is calculated according to the radius of the over-the-top circle and the flying height of the aircraft.

[0073] In the embodiment, the dichotomy method is used to calculate the over-the-top pitch angle when the target enters the over-the-top tracking state in real time, specifically, firstly, when the target enters the over-the-top circle region with the center being directly below the carrier, the radius of the over-the-top circle is calculated by the dichotomy method. Then, the over-the-top pitch angle is calculated according to the radius of the over-the-top circle and the flying height of the aircraft. It can be understood that, in order to fully utilize the azimuth rotating speed, over-the-top at the maximum azimuth speed is the optimal choice of the tracking precision of the program guidance method, that is, the over-the-top pitch angle and the radius of the over-the-top circle solved when the over-the-top azimuth speed is equal to the maximum rotating speed of the shaft system speed are the optimal over-the-top pitch angle and the radius of the over-the-top circle. The dichotomy numerical solution has the characteristics of fast convergence speed, less iteration times and high operation precision. The current computing power level of the embedded device chip can fully meet the operation demand of the dichotomy method.

[0074] As shown in the two-axis two-frame photoelectric device over-the-top tracking control method according to an embodiment of the present application, Figure 3As shown, the two-axis two-frame photoelectric device over-the-top tracking control method according to one embodiment of the present application calculates the over-the-top azimuth angle and the maximum rotation speed of the shaft system speed required by the shaft system position loop, including the following steps:

[0075] Step S302: Obtain the over-the-top azimuth angle and the over-the-top tracking time according to the over-the-top elevation angle.

[0076] Step S304: Obtain the over-the-top azimuth speed according to the over-the-top azimuth angle and the over-the-top tracking time, and obtain the maximum rotation speed of the shaft system speed according to the over-the-top azimuth speed.

[0077] In this embodiment, the over-the-top azimuth angle and the maximum rotation speed of the shaft system speed required by the shaft system position loop are calculated, specifically, the over-the-top azimuth angle and the over-the-top tracking time are first obtained according to the over-the-top elevation angle. Then the over-the-top azimuth speed is obtained according to the over-the-top azimuth angle and the over-the-top tracking time, and the calculated over-the-top azimuth speed is exactly equal to the maximum speed of the device azimuth.

[0078] In some embodiments, optionally, the calculation formula of the over-the-top elevation angle is:

[0079]

[0080] wherein θ Eover is the over-the-top elevation angle, R is the radius of the over-the-top circle, and h is the flying height of the aircraft. The over-the-top elevation angle can be calculated according to the radius of the over-the-top circle and the flying height of the aircraft.

[0081] In some embodiments, optionally, the calculation formula of the over-the-top tracking time is:

[0082]

[0083] wherein t over is the over-the-top tracking time, (x0, y0) is the initial position of the target, v x is the speed of the target along the ox direction of the coordinate system, v y is the speed of the target along the oy direction of the coordinate system, and R is the radius of the over-the-top circle. The over-the-top tracking time can be obtained by the initial position of the target, the speed of the target along the ox direction of the coordinate system, the speed of the target along the oy direction of the coordinate system, and the radius of the over-the-top circle.

[0084] In some embodiments, optionally, the calculation formula of the over-the-top azimuth angle is:

[0085]

[0086] wherein t over is the over-the-top tracking time, θ Aover is the over-the-top azimuth angle, and v xLet v be the velocity of the target along the ox direction of the coordinate system. y Let |AB| be the velocity of the target along the oy direction of the coordinate system, and |AB| be the distance between points A and B. The over-the-top azimuth angle can be obtained by using the over-the-top tracking time, the target's velocity along the ox direction of the coordinate system, the target's velocity along the oy direction of the coordinate system, and the radius of the over-the-top circle.

[0087] In some embodiments, optionally, the formula for calculating the over-the-top azimuth velocity is:

[0088] v Aover =θ Aover / t over ;

[0089] Among them, t over For over-the-top tracking time, θ Aover v is the azimuth angle at the top. Aover This refers to the overpass azimuth velocity. The overpass azimuth velocity can be obtained based on the overpass azimuth angle and the overpass tracking time.

[0090] like Figure 4 As shown, an embodiment of the second aspect of this application provides a two-axis, two-frame optoelectronic device overhead tracking control system 10, comprising: an acquisition module 110, used to acquire the azimuth angle, pitch angle, aircraft altitude, and initial target position of the two-axis, two-frame optoelectronic device under tracking conditions via a three-axis gyroscope; a determination module 120, used to determine the target position and target speed information based on the azimuth angle, pitch angle, and altitude; a real-time calculation module 130, used to calculate the overhead pitch angle when the target enters the overhead tracking state in real time using a binary search method; and a control module 140, used to determine whether the absolute value of the pitch angle is greater than or equal to the overhead pitch angle; if so, calculate the overhead azimuth angle and maximum rotational speed of the shaft system position loop that need to rotate, and perform shaft system position control based on the overhead azimuth angle and maximum rotational speed; if not, perform gyroscope tracking loop control.

[0091] The two-axis two-frame photoelectric device over-the-top tracking control system 10 provided by the embodiment comprises an acquisition module 110, a determination module 120, a real-time calculation module 130 and a control module 140. The acquisition module 110 is configured to acquire the azimuth angle, the pitch angle, the flying height of the aircraft and the initial position of the target of the two-axis two-frame photoelectric device in the tracking state through a three-axis gyroscope. The determination module 120 is configured to determine the target position and the target speed information according to the azimuth angle, the pitch angle and the flying height. The real-time calculation module 130 is configured to calculate the over-the-top pitch angle when the target enters the over-the-top tracking state in real time through the bisection method. The control module 140 is configured to determine whether the absolute value of the pitch angle is greater than or equal to the over-the-top pitch angle. If yes, the over-the-top azimuth angle that the shaft system position ring needs to rotate and the maximum rotating speed of the shaft system speed are calculated, and the shaft system position control is performed according to the over-the-top azimuth angle and the maximum rotating speed. If no, the gyro tracking ring control is performed. The optimal over-the-top pitch angle is found by solving the transcendental equation caused by the geometric relationship in the over-the-top tracking through the bisection method, the azimuth rotating speed of the device is fully utilized to minimize the maximum deviation of the target from the visual axis in the image, and the target can be ensured to be within the field of view in the process of over-the-top tracking to the maximum extent.

[0092] As shown in the first aspect of the present application, Figure 5 The embodiment of the third aspect of the present application provides a two-axis two-frame photoelectric device over-the-top tracking control system 20, which comprises a memory 300 and a processor 400. The memory 300 stores programs or instructions executable on the processor 400. When the processor 400 executes the programs or instructions, the steps of the two-axis two-frame photoelectric device over-the-top tracking control method of any one of the embodiments of the first aspect are implemented, so the technical effects of any one of the embodiments of the first aspect are achieved, which will not be repeated here.

[0093] The embodiment of the fourth aspect of the present application provides a readable storage medium, which stores programs or instructions executable on the processor. When the processor executes the programs or instructions, the steps of the two-axis two-frame photoelectric device over-the-top tracking control method of any one of the embodiments of the first aspect are implemented, so the technical effects of any one of the embodiments of the first aspect are achieved, which will not be repeated here.

[0094] As shown in the first aspect of the present application, Figures 6 to 21 According to the two-axis two-frame photoelectric device over-the-top tracking control method provided by one specific embodiment of the present application, the optimal over-the-top pitch angle is found by solving the transcendental equation caused by the geometric relationship in the over-the-top tracking through the bisection method, the azimuth rotating speed of the device is fully utilized to minimize the maximum deviation of the target from the visual axis in the image, and the target can be ensured to be within the field of view in the process of over-the-top tracking to the maximum extent.

[0095] According to the two-axis two-frame photoelectric device over-the-top tracking control method based on the program guidance method provided by the embodiment, in the case that the target moves at a uniform speed in a straight line relative to the aircraft, the target can be ensured to be within the field of view during the over-the-top tracking.

[0096] First, the position and speed information of the target are calculated by tracking the azimuth and elevation angles of the device and the flying height of the aircraft. A right-hand space rectangular coordinate system is established with the two-axis two-frame photoelectric device as the coordinate origin, as shown in Figure 6 . ox is the heading, oy is the lateral direction, and oz is the vertical direction. The azimuth angle of the device is positive in the direction of the y-axis with the xoz plane as the reference surface, and the azimuth range is [-180°, 180°]. The elevation angle of the device is positive in the direction of the z-axis with the xoy plane as the reference surface, and the elevation range is [-90°, 110°]. The initial coordinates of the target in the coordinate system are [x0 y0 z0] T , the speed of the target P in the ox direction is v x , and the speed in the oy direction is v y . Therefore, in the coordinate system, the coordinates of the target can be represented as: or [h tan (θ E ) -1 ·cos(θ A )h tan (θ E ) -1 ·sin(θ A )h] T , where θ A and θ E are the azimuth and elevation angles of the device axis system, and h is the flying height of the aircraft. Therefore, the position and speed information of the target can be represented by the azimuth and elevation angles of the device and the flying height of the aircraft.

[0097] Second, when the target enters the area range of a circle with the center at the top of the aircraft and a radius of R, the system is determined to be in the over-the-top tracking state, and the corresponding coordinate relationship diagram is shown in Figure 7 .

[0098] When the target passes through point A, the system enters the over-the-top tracking state, and the corresponding elevation angle is marked as θ Eover in Figure 7 . The geometric relationship between θ Eover and the over-the-top circle radius R is:

[0099]

[0100] The azimuth angle that needs to be rotated is marked as θ Aover in the two-dimensional plane. Let the coordinates of point A in the two-dimensional coordinate system of Figure 8 be [x1 y1] T, then the coordinates of point B can be expressed as [x1 + v x t over y1 + v y t over ] T , t over is the time required for the target to move from A to B, i.e. the over-the-top time of the photoelectric device. Since the trajectory of the target intersects the circle twice, the over-the-top time t over can be solved according to the properties of the circle as follows:

[0101]

[0102] The distance between points A and B and θ Aover can be expressed as:

[0103]

[0104] According to the above formula, the azimuth over-the-top velocity v Aover of the device can be calculated as:

[0105] v Aover = θ Aover / t over ;

[0106] The relationship between R and v Aover can be obtained by combining the above equations as follows:

[0107]

[0108] Substituting t over into the above equation gives:

[0109]

[0110] In order to fully utilize the azimuth rotation speed, over-the-top at the maximum azimuth velocity is the optimal choice for the program guidance method, i.e. when v Aover = v Azmax , the calculated θ Eover and R are the optimal over-the-top elevation angle and over-the-top circle radius. Since the above equation is a relatively complex transcendental equation, it is difficult to obtain an analytical solution for R. Therefore, the present embodiment uses the bisection method for numerical solution.

[0111] Let

[0112] f(R) = 0 be the solution of the equation. For the bisection method, the solution of the equation requires the value range of the root of the equation. Since v Aover · t over = θ Aover , the value range of θ Aover is 0° to 180°, so θAover The value of / 2 is in the range of 0° to 90°. In order to find the value range of the equation root, the sin function in the above expression can be linearized to get the analytical expression of R min and R max as the value range of the real value R. The f(x) = sin(x) function is linearized to f(x) = x and f(x) = 2x / π in the domain of 0° to 90°, and the function image is shown in Fig. 1. Figure 9

[0113] In the domain, x ≥ sin(x), 2x / π ≤ sin(x), so when the linearized function is brought into the above expression, the analytical expression of the upper and lower limits of R can be obtained:

[0114]

[0115] The execution steps of the dichotomy are as follows:

[0116] (1). Calculate the value of f(R) at the endpoints of the solution interval [R min R max ].

[0117] (2). Calculate the value f(R1) of f(R) at the midpoint R1 = (R max +R min ) / 2 of the interval.

[0118] (3). If f(R1) = 0, then R1 is the root, otherwise check:

[0119] 1. If f(R1) and f(R min ) are of different signs, it is known that the solution is in the interval [R min R1],

[0120] R max = R1, R min = R min

[0121] 2. If f(R1) and f(R min ) are of the same sign, it is known that the solution is in the interval [R1 R max ],

[0122] R min = R1, R max = R max

[0123] Steps 2 and 3 are repeated to get a series of root intervals

[0124] (4) When |R max_k+1 -R min_k+1 ​| < ξ terminate the calculation. ξ is the self-defined calculation precision, which is set to 1e-6.

[0125] (5) then R = (R max_k+1 + R min_k+1 ) / 2 is the approximate value of the root.

[0126] The Matlab program code and running results of the bisection method are shown in Figure 10 .

[0127] The numerical solution of the bisection method has the characteristics of fast convergence speed, less iteration times, and high operation precision. The current computing power level of embedded device chips can fully meet the operation requirements of the bisection method.

[0128] By solving the radius R of the over-the-top circle through the bisection method, the over-the-top pitch angle θ Eover can be obtained as:

[0129]

[0130] After the over-the-top pitch angle is determined, the over-the-top tracking time t over , the angle θ Aover that needs to be rotated in the azimuth, and the azimuth speed v Aover at the over-the-top time can be calculated according to the above formula. The calculated v Aover is exactly equal to the maximum speed v Azmax that the device azimuth can rotate.

[0131] (1) Beneficial effects on the simulation level:

[0132] Target information and device servo capability under simulation conditions: assuming that the relative height difference h between the target and the aircraft is 300 m, the initial position of the target x0 = y0 = -122.4745 m, the speed of the target along the ox direction v x = -28 m / s, and the speed along the oy direction v y = 30 m / s. The maximum angular speed of the device in the azimuth and pitch is |v Azmax | = |v Elmax | = 60° / s.

[0133] The effectiveness of the over-the-top tracking strategy of the program guidance method is judged by the maximum value of the line-of-sight error angle. The line-of-sight error angle is defined as the angle between the real unit line-of-sight and the ideal unit line-of-sight, and the ideal unit line-of-sight always points to the target, as shown in Figure 11 .

[0134] This line-of-sight error angle can be calculated by the inner product formula of the unit vector angle as:

[0135] e = arccos(sin(θ E )2 +cos(θ E ) 2 ·cos(θ A '-θ A ));

[0136] θ A ' is the azimuth angle of ideal unit boresight, θ A and θ E are the azimuth, elevation angles of real boresight. Based on the above simulation environment, if no any over-the-top tracking strategy is adopted, the error angle of boresight changes with time as shown in Figure 12 .

[0137] If the program guidance method is used as the over-the-top tracking strategy, the error angle of boresight changes with time as shown in Figure 13 .

[0138] From the results, under the tracking conditions (target speed, altitude conditions), the maximum value of the boresight error angle of the program guidance method for over-the-top tracking is reduced by about 2.58 times.

[0139] The beneficial effects of actual device experimental verification are:

[0140] The azimuth and elevation off-target amount of over-the-top tracking without any strategy in a certain type of two-axis two-frame photoelectric device is shown in Figure 14 .

[0141] Under the same experimental conditions (target position, speed change, field of view angle, etc.), the azimuth and elevation off-target amount of the program guidance method for over-the-top tracking using the optimal over-the-top elevation angle calculated based on the bisection method is shown in Figure 15 .

[0142] From the experimental results, the maximum boresight error angle of the program guidance method can be reduced by about 2.3 times.

[0143] Based on the simulation results and experimental results, the program guidance method for over-the-top tracking can effectively reduce the boresight error angle of the two-axis two-frame photoelectric device during over-the-top tracking, and maximize the guarantee that the target can be within the field of view.

[0144] Specifically, (1) using a three-axis gyroscope to enable the two-axis two-frame photoelectric device to have over-the-top stable function:

[0145] If only two-axis gyro is used, there is a secant relationship between the azimuth axis system rotation speed and the azimuth gyro when the pitch is close to the top, and the gyro noise amplitude is constant, thus leading to a sharp increase in the signal-to-noise ratio of the gyro signal after secant compensation to the azimuth axis system, resulting in the phenomenon of self-excited oscillation of the device. Therefore, the device uses a three-axis gyro, which relies on the angular velocity of the gyro azimuth axis and the roll axis to calculate the angular velocity in the azimuth direction, and the device has the function of overtop stability.

[0146] For real-time tracking of the target, the bisection method is used to calculate whether the target enters the overtop:

[0147] When the device enters the tracking state, the azimuth and pitch both use the control loop of Figure 19 for servo closed loop to perform normal tracking. When the absolute value of the pitch angle is greater than θ Eover calculated by the bisection method in real time, the system judges that it enters the overtop state, the bisection method stops calculating θ Eover , and the azimuth switches to the control loop of Figure 20 for servo closed loop, and the bisection method calculates θ Eover in real time. The experimental data curve of the real-time pitch angle absolute value of the device is shown in Figure 16 .

[0148] The given angle of the control loop shown in Figure 20 is θ Aover , and the command speed limit of the position loop PID output is v Aover . In the experiment, the change curves of the device azimuth angle and the azimuth angular velocity are shown in Figure 17 and Figure 18 .

[0149] When the absolute value of the pitch angle is less than θ Eover again, the azimuth switches to the control loop of Figure 19 for normal tracking. The entire logic flowchart of the overtop tracking by the program guide method is shown in Figure 21 . Specifically, step S402: start tracking; step S404: calculate the angle entering the overtop by the bisection method in real time; step S406: judge whether the absolute value of the pitch angle is greater than or equal to θ over ; step S408: if the absolute value of the pitch angle is greater than or equal to θ over , calculate the angle θ Aover that the axis system position loop needs to rotate and the maximum rotation speed V over of the axis system speed; step S410: control the axis system position; step S412: if the absolute value of the pitch angle is less than θ ove , control the gyro tracking loop; and step S414: end tracking.

[0150] In conclusion, the embodiment of the present application has the following advantages: the optimal overtop pitch angle is found by solving the transcendental equation caused by the geometric relationship in overtop tracking, the maximum deviation of the target from the visual axis in the image is minimized by fully utilizing the azimuth rotation speed of the device, and the target can be ensured to be within the field of view during overtop tracking.

[0151] In the present application, the terms "first", "second", "third" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance; the term "multiple" refers to two or more, unless otherwise explicitly limited. The terms "mount", "connect", "connect", "fix" and the like should be broadly understood, for example, "connect" can be fixed connection, can also be detachable connection, or integrally connected; "connected" can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0152] In the description of the present application, it should be understood that the terms "up", "down", "front", "back" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the system or module referred to must have a particular direction, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application.

[0153] In the description of the present application, the terms "one embodiment", "some embodiments", "a specific embodiment" and the like mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0154] The above is only the preferred embodiment of the present application, and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for overhead tracking control of a two-axis, two-frame optoelectronic device, characterized in that, The method comprises the following steps: obtaining, by a three-axis gyroscope, azimuth angle, pitch angle, flying height of an airplane and initial position of a target of a two-axis two-frame photoelectric device in a tracking state; determining target position and target speed information according to the azimuth angle, the pitch angle and the flying height; calculating, in real time, over-the-top pitch angle when the target enters an over-the-top tracking state by dichotomy; judging whether the absolute value of the pitch angle is greater than or equal to the over-the-top pitch angle; if yes, calculating over-the-top azimuth angle and maximum rotating speed of a shaft system speed which the shaft system position ring needs to rotate, and performing shaft system position control according to the over-the-top azimuth angle and the maximum rotating speed; if no, performing gyro tracking loop control; wherein the calculating, in real time, of the over-the-top pitch angle when the target enters the over-the-top tracking state by dichotomy comprises: calculating the radius of an over-the-top circle by dichotomy when the target enters a region range of the over-the-top circle with the airplane directly below as the center; calculating the over-the-top pitch angle according to the radius of the over-the-top circle and the flying height of the airplane; the calculating of the over-the-top azimuth angle and the maximum rotating speed of the shaft system speed which the shaft system position ring needs to rotate comprises: obtaining over-the-top azimuth angle and over-the-top tracking time according to the over-the-top pitch angle; obtaining over-the-top azimuth speed according to the over-the-top azimuth angle and the over-the-top tracking time, and obtaining the maximum rotating speed of the shaft system speed according to the over-the-top azimuth speed.

2. The over-the-top tracking control method of the two-axis two-frame photoelectric device according to claim 1, wherein a calculation formula of the over-the-top pitch angle is:

3. The over-the-top tracking control method of the two-axis two-frame photoelectric device according to claim 2, wherein a calculation formula of the over-the-top tracking time is: ； wherein, is the over-the-top pitch angle, R is the radius of the over-the-top circle, and h is the flying height of the aircraft.

4. The over-the-top tracking control method of the two-axis two-frame photoelectric device according to claim 3, wherein a calculation formula of the over-the-top azimuth angle is:

5. The over-the-top tracking control method of the two-axis two-frame photoelectric device according to claim 4, wherein a calculation formula of the over-the-top azimuth speed is: ； wherein, is the over-the-top tracking time, (x0, y0) is the initial position of the target, is the velocity of the target along the ox direction of the coordinate system, is the velocity of the target along the oy direction of the coordinate system, and R is the radius of the over-the-top circle. The method comprises the following steps: an obtaining module (110) is configured to obtain, by a three-axis gyroscope, azimuth angle, pitch angle, flying height of an airplane and initial position of a target of a two-axis two-frame photoelectric device in a tracking state; ； ； wherein, is the over-the-top tracking time, is the over-the-top azimuth angle, is the velocity of the target along the ox coordinate system, is the velocity of the target along the oy coordinate system, is the distance between points AB. a determining module (120) is configured to determine target position and target speed information according to the azimuth angle, the pitch angle and the flying height; a real-time calculating module (130) is configured to calculate, in real time, over-the-top pitch angle when the target enters an over-the-top tracking state by dichotomy; ； wherein, is the over-the-top tracking time, is the over-the-top azimuth angle, is the over-the-top azimuth velocity.

6. A two-axis two-mirror opto-electronic device over-the-top tracking control system, characterized by, a control module (140) is configured to judge whether the absolute value of the pitch angle is greater than or equal to the over-the-top pitch angle; if yes, calculate over-the-top azimuth angle and maximum rotating speed of a shaft system speed which the shaft system position ring needs to rotate, and perform shaft system position control according to the over-the-top azimuth angle and the maximum rotating speed; if no, perform gyro tracking loop control; wherein the calculating, in real time, of the over-the-top pitch angle when the target enters the over-the-top tracking state by dichotomy comprises: calculating the radius of an over-the-top circle by dichotomy when the target enters a region range of the over-the-top circle with the airplane directly below as the center; calculating the over-the-top pitch angle according to the radius of the over-the-top circle and the flying height of the airplane; ​ ​ ​ ​ ​ The calculation of the over-the-top azimuth angle and the maximum rotation speed of the shaft system position ring requires the over-the-top azimuth angle and the maximum rotation speed of the shaft system speed, comprising: According to the over-the-top pitch angle, the over-the-top azimuth angle and the over-the-top tracking time are obtained; According to the over-the-top azimuth angle and the over-the-top tracking time, the over-the-top azimuth speed is obtained, and according to the over-the-top azimuth speed, the maximum rotation speed of the shaft system speed is obtained.

7. A two-axis two-mirror opto-electronic device over-the-top tracking control system, characterized by, Comprising: A memory (300) and a processor (400), wherein the memory (300) stores programs or instructions executable on the processor (400), and the processor (400) implements the steps of the over-the-top tracking control method of the two-axis two-frame photoelectric device according to any one of claims 1 to 5 when executing the programs or the instructions.

8. A readable storage medium, on which a program or instructions are stored, characterized in that, The programs or the instructions are executed by the processor to implement the steps of the over-the-top tracking control method of the two-axis two-frame photoelectric device according to any one of claims 1 to 5.

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