CN-116777951-B - Window tracking method and system suitable for real-time tracking measurement of small target in air

CN116777951BCN 116777951 BCN116777951 BCN 116777951BCN-116777951-B

Abstract

The invention provides a window tracking method and a system suitable for real-time tracking measurement of small and medium-sized targets in the sky, and calculating the relative motion relation between the measuring satellite and the small aerial target according to the dynamic data of the measuring satellite and the small aerial target forecasted in the measuring time, and calculating the angular position change function of the target relative to the visual axis of the satellite measuring camera. And designing a proper tracking window in the view field of the measuring camera, quickly adjusting the visual axis direction in a certain time when the target moves out of the tracking window, enabling the target to move to the center position of the view field just after the visual axis adjustment is finished, and completing window tracking of the combined target through the repeated holding-adjusting-holding process of the visual axis. The method is reasonable and easy to implement, and solves the problems that the measuring satellite and the target move in the air at high speed, the tracking visual axis direction is required to be continuously adjusted, and the calculation load on the satellite is high.

Inventors

ZHAO QICHANG
DANG JIANCHENG
MIAO PENGFEI
WU YIQUAN
LI YEFEI
ZHANG PENGFEI

Assignees

上海卫星工程研究所

Dates

Publication Date: 20260508
Application Date: 20230505

Claims (4)

1. A window tracking method suitable for real-time tracking measurement of small targets in the air is characterized by comprising the following steps: A space information prediction step of predicting space information in real time according to the information of the measuring satellite and the small target orbit in the air; Converting the position of the small aerial target into a camera measurement coordinate system; calculating the angular displacement of the target relative position vector and the measurement coordinate system; fitting a motion relation curve of the small and medium targets in the sky relative to the measurement satellite according to the calculated relative angular position time sequence, and realizing window tracking according to the motion relation curve; in the spatial information prediction step, the spatial position of the small target in the air is predicted in real time as # ) The speed is% ) Measuring the space position of the satellite as% ) The speed is% ); The coordinate system conversion step includes: a step of converting the satellite orbit coordinate system, which is to convert the position of the small aerial target from the geocentric inertial system to the satellite orbit coordinate system, and convert the matrix into , ; The conversion step of the measuring satellite body coordinate system comprises the step of converting the position of the aerial small target from the satellite orbit coordinate system to the measuring satellite body coordinate system, and converting the matrix into , ; A camera measurement coordinate system conversion step of converting the position of the small aerial target from the measurement satellite body coordinate system to the camera measurement coordinate system, and converting the matrix into , ; Summarizing, namely converting the position of the small aerial target from a geocentric inertial system to a camera measurement coordinate system, and converting the matrix into , ; Wherein R, j and u are the right ascent, the track inclination angle and the right ascent intersection point, Gamma, ψ are satellite attitude angles, beta and θ are pitch and azimuth angles of the oscillating mirror, and M 1 、M 2 and M 3 are rotation matrices; Calculating the relative coordinates of small and medium targets in the camera measurement coordinate system ) Is that ; Calculating the azimuth angle and pitch angle of the relative position vector of the target and the measurement coordinate system as 、 Wherein: ; fitting a motion relation change function of the target relative to the measurement satellite according to the calculated relative angular position time sequence The field of view of the camera is horizontal Vertical, vertical The pixel number M is multiplied by N, and the tracking window size is × , The angle of the target position from the central view field after the single view field adjustment is finished is as follows 、 , The quadrant in the field of view where the target is located is determined by the relative motion angle curve, and is located in the quadrant with the minimum required motion angle of the visual axis, and the window tracking formula is as follows: ; ; ; The subscript out represents a target separating from a view field window, in represents an initial position of the target in the view field, hold represents a view axis/satellite in a maintenance stage, and move represents the view axis/satellite in an adjustment stage; for the time that the object moves within the ith field of view window, The time required for the boresight/satellite to adjust from the ith window to the (i+1) th window, i.e., the time for the target to move out of the ith field of view to the (i+1) th field of view window.
2. The window tracking method suitable for real-time tracking measurement of small and medium-sized targets in space according to claim 1, wherein the motion relation change function Is a quadratic polynomial function.
3. The window tracking method suitable for real-time tracking measurement of small and medium-sized targets in space according to claim 1, wherein the window tracking calculation step comprises setting the center orientation of the visual axis according to the angular position change curve of the targets relative to the satellites, and maintaining the center orientation of the visual axis, when the targets move out of the visual field window, rapidly adjusting the center orientation of the visual axis within a certain time, and enabling the targets to move to the center position of the visual field just after the adjustment of the visual axis is finished, and the window tracking of the combined targets is completed through the repeated maintaining-adjusting-maintaining process of the visual axis.
4. The window tracking system suitable for real-time tracking measurement of small targets in the air is characterized by comprising the following modules: the space information prediction module predicts space information in real time according to the information of the measuring satellite and the small air target orbit; The coordinate system conversion module is used for converting the position of the small aerial target into a camera measurement coordinate system; the angular displacement calculation module is used for calculating the angular displacement of the relative position vector of the target and the measurement coordinate system; The window tracking calculation module is used for fitting a motion relation curve of the small and medium-sized targets in the sky relative to the measurement satellite according to the calculated relative angular position time sequence and realizing window tracking according to the motion relation curve; In the spatial information prediction module, the spatial position of the small target in the air is predicted in real time as # ) The speed is% ) Measuring the space position of the satellite as% ) The speed is% ); The coordinate system conversion module includes: the transformation of the satellite orbit coordinate system is measured, namely the position of a small aerial target is transformed from a geocentric inertia system to a satellite orbit coordinate system, and the transformation matrix is formed by , ; The conversion of the measuring satellite body coordinate system, namely converting the position of the small aerial target from the satellite orbit coordinate system to the measuring satellite body coordinate system, and converting the matrix into , ; Converting the position of small aerial target from the main body coordinate system of measuring satellite to the measuring coordinate system of camera, and converting the matrix into , ; Summarizing, converting the position of the small aerial target from the geocentric inertial system to a camera measurement coordinate system, and converting the matrix into , ; Wherein R, j and u are the right ascent, the track inclination angle and the right ascent intersection point, Gamma, ψ are satellite attitude angles, beta and θ are pitch and azimuth angles of the oscillating mirror, and M 1 、M 2 and M 3 are rotation matrices; Calculating the relative coordinates of small and medium targets in the camera measurement coordinate system ) Is that ; Calculating the azimuth angle and pitch angle of the relative position vector of the target and the measurement coordinate system as 、 Wherein: ; fitting a motion relation change function of the target relative to the measurement satellite according to the calculated relative angular position time sequence The field of view of the camera is horizontal Vertical, vertical The pixel number M is multiplied by N, and the tracking window size is × , The angle of the target position from the central view field after the single view field adjustment is finished is as follows 、 , The quadrant in the field of view where the target is located is determined by the relative motion angle curve, and is located in the quadrant with the minimum required motion angle of the visual axis, and the window tracking formula is as follows: ; ; ; The subscript out represents a target separating from a view field window, in represents an initial position of the target in the view field, hold represents a view axis/satellite in a maintenance stage, and move represents the view axis/satellite in an adjustment stage; for the time that the object moves within the ith field of view window, The time required for the boresight/satellite to adjust from the ith window to the (i+1) th window, i.e., the time for the target to move out of the ith field of view to the (i+1) th field of view window.

Description

Window tracking method and system suitable for real-time tracking measurement of small target in air Technical Field The invention relates to the field of target tracking, in particular to a window tracking method and a system suitable for real-time tracking and measurement of small targets in the air. Background The on-orbit optical measurement camera is utilized to track and measure the air target, and the tracking mode generally adopts an autonomous tracking mode and a program tracking mode. By adopting an autonomous tracking measurement mode, the detection image is required to be processed in real time on the track, the target is extracted, the deviation angle of the target relative to the optical axis of the camera is obtained, and the deviation angle is fed back to the camera tracking servo system to guide the optical axis of the camera to point to the target. The method has the advantages that the flexibility is good, the targets are not easy to get out of the field of view, measurement information is required to be processed in real time on orbit, the requirement on an on-board information processing system is high, and the method is suitable for measurement of non-cooperative targets. By adopting a program tracking mode, a camera tracking program is designed on the ground, the observation time and the tracking program angle of the camera are determined according to the track and the gesture of the target and the satellite, and the program is bound to the satellite to control the optical axis of the camera to point to track and measure the target. The method has the advantages that most of data processing is completed on the ground, the load of the on-board information processing system is small, the method is easy to realize, and the method is suitable for cooperative target measurement. At present, no tracking method for measuring real-time high-speed motion of a satellite and an aerial target is studied, and scheme design of a satellite measurement camera is restricted to a certain extent. The real-time full-automatic capturing method for the near-earth and medium-high orbit aerial targets disclosed by the patent document CN102538759B is characterized in that the aerial targets are measured on the ground, the positions of ground telescopes are fixed and unchanged, the spatial positions of the ground telescopes are not required to be predicted in real time, and the method is not suitable for scenes in which both the targets and the measurement satellites move. The real-time tracking method of the infrared image target based on the multi-feature fusion disclosed in the patent document CN102930558A and the all-weather real-time tracking method of the target based on the visible light and the infrared image disclosed in the patent document CN106485245A are ground target tracking methods based on images, and are not suitable for tracking the air target which needs to adjust and measure the visual axis direction of a camera in real time. The method for detecting and identifying the aerial target by using the infrared imaging equipment disclosed in the patent document CN102982333A is a method for identifying the target by adopting a target contour extraction method and simultaneously utilizing multiple characteristics of the target, and is not suitable for identifying and tracking small targets with unobvious morphological characteristics. The method and the device for determining the track of the air target disclosed in the patent document CN102981160B are a technology for acquiring a preset radar measurement noise parameter and acquiring dynamic detection points of the air target at different moments based on the air target motion model at least according to the radar measurement noise parameter, and are not suitable for satellite on-orbit tracking measurement. Disclosure of Invention Aiming at the defects in the prior art, the invention aims to provide a window tracking method and a system suitable for real-time tracking and measurement of small targets in the air. The window tracking method suitable for real-time tracking measurement of small and medium-sized targets in the sky provided by the invention comprises the following steps: A space information prediction step of predicting space information in real time according to the information of the measuring satellite and the small target orbit in the air; Converting the position of the small aerial target into a camera measurement coordinate system; calculating the angular displacement of the target relative position vector and the measurement coordinate system; and window tracking calculation, namely fitting a motion relation curve of the small and medium targets in the sky relative to the measurement satellite according to the calculated relative angular position time sequence, and realizing window tracking according to the motion relation curve. Preferably, in the spatial information prediction step, the spatial position of the small air target