Target track simulation method of infrared searching and tracking equipment

Abstract

The invention discloses a target track simulation method of infrared searching and tracking equipment. Firstly, speed components in the X direction and the Y direction are calculated according to the movement speed and the course angle of a target; then, according to the speed of the target in the X direction and the rotating speed of the equipment, the time when the current frame equipment detects the target is accurately calculated, specifically, equal-time-interval discretization is carried out on the 360-degree azimuth angle of the equipment, rough prediction is carried out on the time when the equipment detects the target, and linear interpolation is carried out on the rough prediction time to achieve accurate time prediction; and finally, calculating an azimuth angle and a pitch angle of the current frame target by combining the movement speeds of the target in the X direction and the Y direction and the distance between the target and the equipment. According to the method, accurate time simulation of each frame of target is realized through azimuth angle equal-time discretization and linear interpolation methods, accurate simulation of the azimuth angle and the pitch angle is finally realized, and the accuracy of target track simulation is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of photoelectric simulation, in particular to a target track simulation method of infrared search and tracking equipment. Background Art

[0002] The injection simulation system can reduce the manpower and material costs and equipment loss of field testing, save the time cost of developing target detection and recognition algorithms, provide a platform guarantee for the continuous upgrading of algorithms, and provide technical support for the development of infrared search and tracking systems. Therefore, it is particularly important to strengthen the research on the injection simulation system.

[0003] The prerequisite of the injection simulation system is to simulate the target's track to obtain the target's position information (azimuth and pitch angle) in each frame of the image. However, due to the relative motion between the target and the device, there is an error in the time when the device detects the target in each frame of the image, which ultimately leads to errors in the azimuth and pitch angles of the target in the simulated track. The greater the target azimuth speed, the greater the angular error. Therefore, improving the accuracy of target track simulation in the injection simulation system becomes a daunting task.

[0004] For track simulation technology, the traditional algorithm simulates the position of the target detected by the device based on the time intervals such as the device scanning cycle, ignoring the movement of the target, resulting in low accuracy of the simulated position of the target track. When the target and the device are in relative motion, and the rotational angular velocity of the device is much greater than the angular velocity of the target, the angle at which the simulated device detects the target is similar to the problem of pursuit. The present invention discretizes the time intervals such as the azimuth angle of the device, and then linearly interpolates the potential time intervals to infinitely approach the position where the device's line of sight meets the target, which can greatly improve the accuracy of the target track simulation and is of great significance to the research on injection simulation systems. Summary of the invention

[0005] The purpose of the present invention is to provide a target track simulation method for infrared search and tracking equipment to solve the problem of low target track simulation accuracy in the prior art. The method of the present invention realizes accurate time simulation of each frame of the target through the method of azimuth and other time discretization and linear interpolation, and finally realizes accurate simulation of azimuth and pitch angles, effectively improving the accuracy of target track simulation.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] A target track simulation method for an infrared search and tracking device, characterized in that it comprises the following steps:

[0008] First, the velocity components in the X and Y directions are calculated according to the target's moving speed and heading angle;

[0009] Then, the time when the infrared search and tracking device detects the target in the current frame is more accurately calculated according to the speed of the target in the X direction and the rotation speed of the infrared search and tracking device. The specific method is: the 360° azimuth angle of the device is discretized at equal time intervals to roughly predict the time when the infrared search and tracking device detects the target, and the rough prediction time is linearly interpolated to achieve a more accurate time prediction;

[0010] Finally, the azimuth and elevation angles of the target in the current frame are calculated by combining the target's movement speed in the X and Y directions and the distance between the target and the infrared search and tracking device.

[0011] The target track simulation method of the infrared search and tracking device is characterized in that the method comprises the following steps:

[0012] A. Calculate the target's velocity components V in the X and Y directions based on the target's velocity V and heading angle h. x and V y :

[0013] V x =V*sin(h)

[0014] V y =V*cos(h)

[0015] B. Target simulation time calculation:

[0016] a) Make a rough prediction of the simulation time based on the sampling of equal time intervals of the device azimuth;

[0017] The 360° azimuth angle of the device is adjusted by d Sampling once per second, assuming the device speed is T per revolution c seconds, then the device scans a circle, and the total number of samples N is:

[0018]

[0019] The azimuth angle of the device during each sampling interval is:

[0020]

[0021] The azimuth of the device after the current sampling moment is:

[0022] azi d_t =azi d_t-1 +azi d

[0023] The azimuth angle of the device at the initial sampling moment is 0°;

[0024] The azimuth of the target after the current sampling moment is

[0025]

[0026] Y t =Y t-1 +T d *V y

[0027] X t =X t-1 +T d *V x

[0028] Among them, X t-1 and Y t-1 are the coordinate positions of the target in the X and Y directions after the last sampling moment, respectively. t and Y t They are the coordinate positions of the target in the X and Y directions after the current sampling moment respectively;

[0029] After the current sampling moment, the azimuth of the device is less than the azimuth of the target, that is, Δ d_t-1 <0; and the azimuth of the device after the current sampling moment is greater than the azimuth of the target, Δ d_t >0, the device detects the target within the current sampling interval, that is:

[0030] Δ d_t-1 <0&&Δ d_t >0

[0031] Δ d_t =azi d_t -azi t_t

[0032] Δ d_t-1 =azi d_t-1 -azi t_t-1

[0033] Among them, azi d_t-1 and azi t_t-1 is the azimuth of the device and the azimuth of the target after the last sampling moment, and the current sampling interval is the simulation time of the rough prediction;

[0034] b) Linearly interpolate the rough prediction time to further accurately predict the simulation time;

[0035] Linearly interpolate the coarse prediction sampling interval:

[0036]

[0037] Δ0 d_t =azi d_t -k*Δ d_t

[0038] Where k is (Δ d_t-1 ,azid_t ) and (Δ d_t ,azi d_t-1 ) determines the slope of the line, Δ0 d_t The device azimuth angle corresponding to the time when the difference between the device azimuth angle and the target azimuth angle is 0;

[0039] The time T when the device detects the target in the current frame is:

[0040]

[0041] Among them, T c The time it takes for the device to rotate once, in seconds;

[0042] C. Calculate the azimuth and pitch angle of the target in the current frame based on the time when the device detects the target and the speed of the target in the X and Y directions:

[0043]

[0044]

[0045] Among them, X T , Y T , Z T The three-coordinate position of the target when the device detects the target:

[0046] X y =V x *T

[0047] Y T =V x *T.

[0049] The main difficulty of track simulation is the calculation of the time when the device detects the target. Due to the relative motion between the target and the device, the device will produce errors in the calculation of the detection time of the target, and the existence of time errors will reduce the simulation accuracy of azimuth and pitch angles. The traditional method simulates the position of the target detected by the device based on the time interval such as the scanning cycle of the device, ignoring the movement of the target.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] 1. The method of the present invention takes into account the relative motion between the target and the device, reduces the time error of the device detecting the target, and improves the simulation accuracy of the azimuth and elevation angles.

[0052] 2. The calculation process in the method of the present invention is relatively simple, which is convenient for improving the real-time performance of the injection simulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 Flow chart of the method of the present invention.

[0054] Figure 2 This is the simulation result of the azimuth of the track.

[0055] Figure 3 is the simulation result of the pitch angle of the track.

[0056] Figure 4 This is a comparison diagram of the azimuth simulation error between the present invention and the traditional method. DETAILED DESCRIPTION

[0057] See also Figure 1 , the present invention discloses a target track simulation method of an infrared search and tracking device.

[0058] As shown in the figure: It includes the following steps:

[0059] First, the velocity components in the X and Y directions are calculated according to the target's moving speed and heading angle;

[0060] Then, the time when the infrared search and tracking device detects the target in the current frame is more accurately calculated according to the speed of the target in the X direction and the rotation speed of the infrared search and tracking device. The specific method is: the 360° azimuth angle of the infrared search and tracking device is discretized at equal time intervals to roughly predict the time when the infrared search and tracking device detects the target, and the rough prediction time is linearly interpolated to achieve a more accurate time prediction;

[0061] Finally, the azimuth and elevation angles of the target in the current frame are calculated by combining the target's movement speed in the X and Y directions and the distance between the target and the infrared search and tracking device.

[0062] Specifically, the method comprises the following steps:

[0063] A. Calculate the target's velocity components V in the X and Y directions based on the target's velocity V and heading angle h. x and V y :

[0064] V x =V*sin(h)

[0065] V y =V*cos(h)

[0066] B. Target simulation time calculation:

[0067] a) Make a rough prediction of the simulation time based on the azimuth and equal time interval sampling of the infrared search and tracking device;

[0068] The infrared search and tracking device 360° azimuth is adjusted per T d Sampling once per second, assuming that the infrared search and tracking device rotates at a speed of T per revolution cseconds, then the infrared search and tracking device scans a circle, and the total number of sampling times N is:

[0069]

[0070] The azimuth angle of the device during each sampling interval is:

[0071]

[0072] The azimuth of the infrared search and tracking device after the current sampling moment is:

[0073] azi d_t =azi d_t-1 +azi d

[0074] The azimuth angle of the infrared search and tracking device at the initial sampling moment is 0°;

[0075] The azimuth of the target after the current sampling moment is

[0076]

[0077] Y t =Y t-1 +T d *V y

[0078] X t =X t-1 +T d *V x

[0079] Among them, X t-1 and Y t-1 are the coordinate positions of the target in the X and Y directions after the last sampling moment, respectively. t and Y t They are the coordinate positions of the target in the X and Y directions after the current sampling moment respectively;

[0080] After the current sampling moment, the azimuth of the infrared search and tracking device is less than the azimuth of the target, that is, Δ d_t-1 <0; and the azimuth of the infrared search and tracking device after the current sampling moment is greater than the azimuth of the target, Δ d_t >0, the infrared search and tracking device has detected the target within the current sampling interval, that is:

[0081] Δ d_t-1 <0&&Δ d_t >0

[0082] Δ d_t =azi d_t -azi t_t

[0083] Δ d_t-1 =azi d_t-1 -azi t_t-1

[0084] Among them, azi d_t-1 and azi t_t-1 is the azimuth of the infrared search and tracking device and the azimuth of the target after the last sampling moment, and the current sampling interval is the coarsely predicted simulation time;

[0085] b) Linearly interpolate the rough prediction time to further accurately predict the simulation time;

[0086] Linearly interpolate the coarse prediction sampling interval:

[0087]

[0088] Δ0 d_t =azi d_t -k*Δ d_t

[0089] Where k is (Δ d_t-1 ,azi d_t ) and (Δ d_t ,azi d_t-1 ) determines the slope of the line, Δ0 d_t The azimuth of the infrared search and tracking device corresponding to the time when the difference between the azimuth of the infrared search and tracking device and the azimuth of the target is 0;

[0090] The time T when the infrared search and tracking device detects the target in the current frame is:

[0091]

[0092] Among them, T c The time it takes for the infrared search and tracking device to make one rotation, in seconds;

[0093] C. Calculate the azimuth and pitch angle of the target in the current frame based on the time when the infrared search and tracking device detects the target and the speed of the target in the X and Y directions:

[0094]

[0095]

[0096] Among them, X T , Y T , Z T When the infrared search and tracking device detects a target, the three-coordinate position of the target is:

[0097] X y =V x *T

[0098] Y T =V x *T.

[0100] The technical solutions in the implementation of the present invention will be described in detail below with reference to the accompanying drawings.

[0101] Simulation environment: Visual Studio 2019, matlab2016a;

[0102] Simulation method: Assume that the rotation speed of the device is 300° / s, that is, 1.2 seconds per revolution, the initial distance of the target from the device is 5km, the initial azimuth is 0°, the azimuth is the angle between the target and the true north, the target heading angle is 120°, the heading angle refers to the angle between the target flight direction and the true north, the target flight altitude is 2km, and the target speed is 0.3Ma. The simulation generates N consecutive frames of azimuth and pitch angles of the target detected by the infrared search device.

[0103] According to the heading angle and initial distance of the target, it can be judged that the target is moving from far to near and then away from the device. The pitch angle becomes larger and larger as the target moves from far to near. When the target flies to the closest distance to the device, the pitch angle reaches the maximum value. Then the target moves away from the device, and the pitch angle of the target gradually decreases. Figure 3 It can be seen from the pitch angle image of the target relative to the device that the pitch angle generated by the simulation is consistent with the actual situation.

[0104] The heading angle of the target is 120°, and the initial azimuth is 0°, which means that during the entire flight, the azimuth of the target increases from 0°. When moving away infinitely along the route, the azimuth approaches 180°. As the target moves away, its area gradually decreases. When it reaches a certain distance, the device will not be able to detect the target. Figure 2 As shown in the figure, the azimuth of the target does not approach 180°, and the change trend of the entire azimuth is consistent with the analysis of the actual situation.

[0105] from Figure 2 and Figure 3 It can be seen from the comparative analysis that when the pitch angle reaches the maximum value, the target is at the closest position to the device. At this time, the azimuth speed of the target is the largest and the azimuth changes the fastest, which is consistent with the actual situation.

[0106] Figure 4 This is a comparative analysis of the simulation accuracy of the present simulation algorithm and the traditional algorithm. It can be seen from the figure that the angular error of the present algorithm is relatively small, the simulation accuracy is high, and no matter how the azimuth angular velocity changes, the simulation error is always maintained at a small level.

Claims

1. A target track simulation method for an infrared search and tracking device, characterized in that: It includes the following steps: First, the velocity components in the X and Y directions are calculated according to the target's moving speed and heading angle; Then, the time when the infrared search and tracking device detects the target in the current frame is more accurately calculated according to the speed of the target in the X direction and the rotation speed of the infrared search and tracking device. The specific method is: the 360° azimuth angle of the infrared search and tracking device is discretized at equal time intervals to roughly predict the time when the infrared search and tracking device detects the target, and the rough prediction time is linearly interpolated to achieve a more accurate time prediction; Finally, the azimuth and elevation angles of the target in the current frame are calculated by combining the target's movement speed in the X and Y directions and the distance between the target and the infrared search and tracking device.

2. The target track simulation method of the infrared search and tracking device according to claim 1 is characterized in that: The method comprises the following steps: A. Calculate the target's velocity components V in the X and Y directions based on the target's velocity V and heading angle h. x and V y : V x =V*sin(h) In y =V*cos(h) B. Target simulation time calculation: a) Make a rough prediction of the simulation time based on the azimuth and equal time interval sampling of the infrared search and tracking device; The infrared search and tracking device 360° azimuth is adjusted per T d Sampling once per second, assuming that the infrared search and tracking device rotates at a speed of T per revolution c seconds, then the infrared search and tracking device scans a circle, and the total number of sampling times N is: The azimuth angle of the device during each sampling interval is: The azimuth of the infrared search and tracking device after the current sampling moment is: today d_t =today d_t-1 +today d The azimuth angle of the infrared search and tracking device at the initial sampling moment is 0°; The azimuth of the target after the current sampling moment is Y t =Y t-1 +T d *V y X t =X t-1 +T d *V x Among them, X t-1 and Y t-1 are the coordinate positions of the target in the X and Y directions after the last sampling moment, respectively. t and Y t They are the coordinate positions of the target in the X and Y directions after the current sampling moment respectively; After the current sampling moment, the azimuth of the infrared search and tracking device is less than the azimuth of the target, that is, Δ d_t-1 <0; and the azimuth of the infrared search and tracking device after the current sampling moment is greater than the azimuth of the target, Δ d_t >0, the infrared search and tracking device has detected the target within the current sampling interval, that is: D d_t-1 <0&&D d_t >0 Δ d_t =today d_t -today t_t Δ d_t-1 =today d_t-1 -today t_t-1 Among them, azi d_t-1 and azi t_t-1 is the azimuth of the infrared search and tracking device and the azimuth of the target after the last sampling moment, and the current sampling interval is the coarsely predicted simulation time; b) Linearly interpolate the rough prediction time to further accurately predict the simulation time; Linearly interpolate the coarse prediction sampling interval: D0 d_t =azi d_t -k*D d_t Where k is (Δ d_t-1 ,azi d_t ) and (Δ d_t ,azi d_t-1 ) determines the slope of the line, Δ0 d_t The azimuth of the infrared search and tracking device corresponding to the time when the difference between the azimuth of the infrared search and tracking device and the azimuth of the target is 0; The time T when the infrared search and tracking device detects the target in the current frame is: Among them, T c The time it takes for the infrared search and tracking device to make one rotation, in seconds; C. Calculate the azimuth and pitch angle of the target in the current frame based on the time when the infrared search and tracking device detects the target and the speed of the target in the X and Y directions: Among them, X T , Y T , Z T When the infrared search and tracking device detects a target, the three-coordinate position of the target is: X T =V x *T Y T =V y *T。

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