An analog device for automatic detection and tracking of small space objects

Abstract

The application relates to a simulation device for automatic detection and tracking of a small space target, belonging to the technical field of space optical remote sensing, and comprising an imaging simulation source, two sets of three-axis high-frequency measuring turntables with three-axis freedom, a PXI integrated controller and a deployment management data display unit. In the process of executing the detection of the small space target, the imaging simulation source simulates the real-time changes of the brightness, volume and background of the small space target under the control of the PXI integrated controller, the camera collects image data, the star sensor calculates the attitude and orbit data, the PXI integrated controller accurately detects the position of the target and controls the angle of the turntable, the camera locks the dynamic small target, and a stable tracking state is maintained. Through the establishment of a loop test system, the semi-physical satellite joint imaging and identification system is tested on the simulated star background, and the actual performance of the test software and the communication system is tested.

Description

Technical Field

[0001] This invention belongs to the field of space optical remote sensing technology, specifically relating to a simulation device for automatic detection and tracking of small space targets. Background Technology

[0002] The construction of space networks and missile defense systems is now imperative, and accurate and real-time monitoring of threatening satellites in space plays a crucial role in national defense and information security. Dual-satellite small target identification systems can achieve 3D detection of small satellites using the principle of visual interleaving, offering significant advantages in identifying swarms of satellites and multiple independently targetable reentry vehicles (MIRVs) that use mutual cover and camouflage. However, high-resolution space small target identification systems are limited by the complexity of dual-satellite synchronization and system mission planning, and lack standardized system construction examples, resulting in large errors and low stability in the current localization and tracking of space targets.

[0003] The main reasons for the difficulty in mission planning during satellite in-orbit flight include: real-time changes in satellite attitude, random changes in target trajectory, and synchronous information exchange between the two satellites. Based on the spatial relationship between the target and the two satellites, missions can be categorized into obtuse-angle close-range observation, acute-angle long-range tracking, and unidirectional ultra-long-range target identification. These three scenarios require rapidly changing adjustments to the system camera's focal length, field of view, and aperture, and the central computer's image processing methods also differ for various image sizes. The coordination and cooperation of these systems involve numerous steps, resulting in significant measurement errors. Therefore, there is an urgent need to provide a simulation device that can offer strong guidance for addressing the problems existing in current methods or simulation systems for the automatic detection and tracking of small space targets. Summary of the Invention

[0004] To address the challenges of identifying and tracking threatening targets in existing small space satellite constellations, this invention provides a simulation device for the automatic detection and tracking of small space targets.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A simulation device for automatic detection and tracking of small targets in space, comprising:

[0007] An imaging simulation source used to simulate real-time changes in brightness, volume, and background of small targets in space under the control of a PXI integrated controller;

[0008] Two sets of three-axis high-frequency test turntable respectively install actuator, the actuator includes three degrees of freedom turntable, star sensor, camera and central machine, the turntable receives the attitude and orbit control instruction of PXI integrated controller, quickly turns to the specified direction, the camera starts to collect target image to the imaging analog source, the star sensor returns real-time attitude and orbit data to the PXI integrated controller, the camera returns image data to the PXI integrated controller, the central machine is connected with the PXI integrated controller by wireless, for attitude and orbit control instruction receiving, image data and attitude and orbit data sending;

[0009] PXI integrated controller, for controlling the time synchronization of the whole system, obtaining the target position information at this moment by analyzing image data and attitude and orbit data, and correcting the attitude of the turntable, and for sending angle modulation instruction in real time by the dynamics and kinematics Simulink module deployed therein, real-time control the angle of three-axis high-frequency test turntable, make the camera lock dynamic small target and keep stable tracking state, and real-time update the background target of imaging analog source, and for calculating the turntable movement error and star sensor error, and comparing them with the expected value;

[0010] The deployment management data display unit realized by the remote computer is used for user monitoring and programming use, can generate user interaction interface, and can observe data measurement results and artificially adjust the parameters of each component of the device at any time.

[0011] Compared with the prior art, the present application has the beneficial effects that: the present application provides a simulation device for automatic detection and tracking of high-precision space small targets, and the identification process of the simulated space target in the near, medium and far field scenes is tested respectively, and the feasibility of the detection algorithm and the whole system can be verified in the most stringent test environment by moving the position of the high-frequency target. The real satellite cooperative work is simulated by using the PXI high-precision time synchronization technology, so that the orderly and stable operation of the system can be ensured. Finally, the deficiencies and defects of each double-star positioning are analyzed by a complete set of data processing system, and the existing algorithm is continuously optimized. The present application tests the semi-physical satellite joint imaging and identification system on the simulated starry sky background by building a loop test system, and tests the actual performance of the test software and communication system. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is a structure schematic view of the simulation device for automatic detection and tracking of space small targets of the present application;

[0013] Figure 2 It is a flowchart of the simulation device for automatic detection and tracking of space small targets of the present application;

[0014] Figure 3Design diagram for the serial communication protocol between the target control computer and the PXI integrated controller;

[0015] Figure 4 The bus layout and time synchronization method for communication between the PXI integrated controller and other devices. Detailed Implementation

[0016] The simulation device of the present invention will be further described in detail below with reference to the embodiments given in the accompanying drawings.

[0017] like Figure 1 As shown, a simulation device for automatic detection and tracking of small targets in space includes an imaging simulation source, two sets of three-axis high-frequency rotating platforms with three degrees of freedom, a PXI integrated controller, and a deployment management data display unit.

[0018] Specifically, the imaging simulation source is used to simulate real-time changes in the brightness, volume, and background of small targets in space under the control of the PXI integrated controller. The imaging simulation source includes a target control computer and two large LED screens. The two screens work simultaneously, providing different visual effects for the turntable from different perspectives. During the small target detection process, the binocular vision system can provide more accurate positional information.

[0019] Furthermore, the imaging simulation source includes a target control computer and two LED screens. The target image and high-frequency vibration curve are input into the target control computer. The target control computer simulates the TDI CCD multi-level imaging process after the high-frequency amplitude and curve are fused, outputs a target image with mixed high-frequency vibration, and controls both LED screens to display the target image.

[0020] Actuators are installed on two high-performance triaxial high-frequency measuring turntables. Each actuator includes a three-degree-of-freedom turntable, a star sensor, a camera, and a central unit mounted on the turntable. Upon receiving control commands from the PXI integrated controller, the turntable quickly rotates to the designated position, and the camera immediately begins measurement, acquiring target images from the imaging simulation source. The star sensor returns real-time attitude and trajectory data, and the camera returns image data, both of which are sent to the PXI integrated controller via the central unit. The central unit is wirelessly connected to the PXI integrated controller for receiving attitude and trajectory control commands and transmitting image and attitude and trajectory data.

[0021] The satellite dynamics, kinematics model and image high-speed processing are integrated into the PXI integrated controller, the PXI integrated controller controls time synchronization of the whole system, realizes millisecond level synchronization of each subsystem, the PXI integrated controller processes and analyzes images of two systems based on an image detection model, after analyzing image data and attitude and orbit data, target position information at this moment is obtained, and the turntable attitude is corrected; the PXI integrated controller is also used for sending angle modulation instructions in real time by the deployed dynamics and kinematics Simulink module, controlling the angle of the three-axis high-frequency turntable in real time, controlling the turntable to gather light on a dynamic small target, making the camera lock the dynamic small target and keep a stable tracking state, and updating the background target of the imaging simulation source in real time, simulating the space small target locking and tracking in the real starry sky background; the PXI integrated controller is also used for error calculation, that is, calculating the turntable movement error and star sensor error, and comparing them with the expected value, and then verifying the precision and reliability of the turntable and the star sensor.

[0022] The deployment management data display unit is realized by a remote computer (PC), is used for user monitoring and programming use, can generate a user interaction interface, can observe data measurement results at any time and artificially adjust parameters of each component of the device, so as to simulate a satellite control ground task.

[0023] In the above simulation device, the independent operating actuator and the three-axis high-frequency turntable are connected by bearings, the camera collects information of the imaging simulation source by adopting a wireless network mode to be connected with the PXI integrated controller, so as to exclude the interference of the cable on the turntable, the PXI integrated controller and the target control computer in the imaging simulation source are connected by a serial port, and the PXI integrated controller and the deployment management data display unit are connected by a gigabit network cable.

[0024] As shown in Figure 1 The star sensor data transmission management terminal can determine the satellite attitude through a star map, and transmit to the attitude simulation module running in the PXI integrated controller, so that the satellite can "perceive" its own position in real time, and generate corresponding remote sensing data. The GPS signal simulator generates simulated GPS time difference information based on the position of the satellite and based on a priori algorithm, and is used for simulation system positioning.

[0025] The specific working principle of the simulation device of the present application is as follows: in the process of detecting a small target in space, first, the target control computer in the imaging simulation source generates a simulated dynamic target and a complex background thereof, and projects them onto an LED large screen, so as to simulate a dynamic target through the large screen, and a turntable simulates a satellite attitude control system, so as to realize a scaled simulation of space measurement; a camera fixed on the turntable receives target information and transmits the information to a central computer for preliminary judgment. A star sensor acquires a star map background corresponding to an angle, and calculates the attitude and orbit data of an actuator. A communication network returns the information to a PXI integrated controller one by one, the controller is responsible for accurately detecting the position of the target, and a dynamics and kinematics Simulink module disposed therein controls the angle of the turntable in real time, so that the turntable is maneuvered and aimed at the target. The background target of the large screen is updated in real time. The constructed motion scene enables the turntable to have simulated orbits of 6 roots, and the target also has its own three-dimensional characteristics. Through the cyclic test network setting, the target to be searched can be changed at any time, and the ability of automatic detection and identification of the test system can be tested. Through multi-dimensional information collaborative test, the advantages and effects of the binocular vision system for distance detection and 3D space position detection are verified compared with the traditional GPS positioning or monocular vision system.

[0026] As shown in Figure 2 The cyclic link of the simulation device of the present application is as follows: the PXI provides an expected attitude, generates a PID control instruction, guides the turntable to move to a specified angle, then the star sensor receives a signal, generates corresponding attitude data, and finally transmits the data back to the PXI for CRC attitude verification, so as to verify the accuracy and real-time performance of the system. The cyclic frequency set in the communication process of the whole system is 10Hz, the Custom Device controls the opening and closing of the serial port and network port and the data flow mode, and clear window interfaces of the data interface of the central control computer and the upper computer are constructed by means of Labview and Qt, so as to facilitate the modification of the information link and the regulation of the data. In the Veristand UI, four areas of the large screen assembly control, the turntable assembly control, the camera assembly control and the star assembly control are set.

[0027] The simulation device for automatic detection and tracking of a small target in space proposed in the present application is specifically illustrated as follows.

[0028] The dynamic target real-time refresh rate used in this embodiment is 60Hz, the resolution is 3840x2160, and the pixel interval is p2. The real-time sampling frequency of the star sensor motion mechanism is 10Hz, and the lowest identified star magnitude is designed to be 5. The X-axis of the turntable is uniformly rotated from 0° to 180°, which takes 20s. The size of the dynamic target is designed to be 15 pixels, and it is disguised in a star group of the same size, but at another viewing angle, it can be shown that it does not completely overlap with the star group, and the moving speed is relatively fast. Complete the execution of the device, obtain the coordinate information of the disguised space target, and implement tracking. The attitude control frequency is set to 10Hz, consistent with the star sensor frequency. The wireless network data transmission bandwidth reaches 1200Mbps, the video is compressed and transmitted, and 1080p video transmission of 20Hz is realized.

[0029] For target motion, set the unit time t E The moving distance is 200 pixels, and the amplitude range of the pixel motion within the exposure time is always limited to 200x2mm.

[0030] In this embodiment, the distance of the target disturbance from the binocular intersection point is:

[0031] d(t E )=400mm

[0032] Assuming it moves 45 degrees diagonally upward, the angles that the two turntables need to rotate are:

[0033]

[0034]

[0035] Where L is the distance between the target and the turntable, which is 5m in size, and l is the distance between the two turntables, which is 2m in size, is the target movement vector size, is the direction vector of the target movement, is the x-axis vector direction, is the y-axis vector direction.

[0036] In this embodiment, the sensitivity of the turntable is 9° / s, so the minimum requirement for turntable control is T>3Hz.

[0037] In this embodiment, the PXI image solving period is 11ms, which meets the requirement. The system synthesis error is:

[0038] ΔΣ=δ(c)+δ(d)+δ(m)

[0039] Where δ(c) represents the angle measurement error, δ(d) is the distance measurement error, and δ(m) is the image recognition error.

[0040] As Figure 3 shown, the interface function is responsible for the analysis and verification of the data packet, to ensure that no obvious error occurs in the process of data transmission. After receiving the data, the interface function will detect whether the RS485 interface is interrupted in real time, and if the data interruption is detected, the data transmission task will be stopped immediately, and the error information will be reported to the PXI integrated controller, and the next instruction will be issued by the PXI integrated controller. The control process of the target follows a reliable serial communication protocol to ensure that the information transmission will not be disturbed. These hardware advantages ensure that the error introduced in the total control of the system can be basically ignored. It is feasible to evaluate the system error by taking the star map generated by the large screen as the standard map and taking the preset angle as the reference value.

[0041] As Figure 4 shown, the simulation device of the application belongs to a kind of semi-physical simulation system, which establishes the communication link between hardware and simulation software based on PXI TriggerBus (8TTL Triggers) bus as a bridge, simulates the real hardware running test environment. The PXI integrated controller serves as the control brain of the simulation system, responsible for managing the connection mode and running time of each link, and providing a channel for user monitoring and interaction. In the whole system, the time sampling frequency of PXI determines the accuracy of the whole sampling data. The clock frequency of PXI is as high as 100MHz, which is much higher than the minimum requirement of the system. The satellite dynamics and attitude control are in the form of separate modules, which are accurate and reliable. It will not cause excessive interference to the implementation, but can improve the accurate positioning of the target area background position.

[0042] Obviously, the above embodiments are only examples for the purpose of clarity, and are not limited to the implementation. For ordinary skilled persons in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A simulation device for automatic detection and tracking of small objects in space, characterized in that, It comprises: An imaging simulation source for simulating real-time changes of brightness, volume and background of a small space target under the control of a PXI integrated controller; the imaging simulation source comprises a target control computer and two LED large screens, a target image and a high-frequency vibration curve are input into the target control computer, the target control computer simulates a TDICCD multi-stage imaging process after the high-frequency amplitude and the curve are fused, outputs the target image with mixed high-frequency vibration, and controls the two LED large screens to display the target image; Two sets of three-axis high-frequency test turntables respectively installed with an executing mechanism; the executing mechanism comprises a three-degree-of-freedom turntable, a star sensor, a camera and a central machine; the turntable receives an attitude and orbit control instruction from the PXI integrated controller, quickly turns to a specified direction, the camera starts to collect a target image of the imaging simulation source, the star sensor returns real-time attitude and orbit data to the PXI integrated controller, the camera returns image data to the PXI integrated controller, and the central machine is connected with the PXI integrated controller through wireless connection, used for receiving an attitude and orbit control instruction, sending image data and attitude and orbit data; The PXI integrated controller is used for controlling time synchronization of the whole system, obtaining target position information at the moment by analyzing image data and attitude and orbit data, correcting a turntable attitude, sending an angle modulation instruction in real time by a dynamics and kinematics Simulink module deployed therein, controlling an angle of the three-axis high-frequency test turntable in real time, making the camera lock a dynamic small target and keep a stable tracking state, updating a background target of the imaging simulation source in real time, calculating a turntable movement error and a star sensor error, and comparing them with respective expected values; A deployment management data display unit realized by a remote computer, used for user monitoring and programming use, capable of generating a user interactive interface, observing data measurement results at any time and manually adjusting parameters of various components of the device.

2. The simulation device for automatic detection and tracking of small space objects according to claim 1, characterized in that, The executing mechanism and the three-axis high-frequency test turntable are connected through bearings, the camera is connected with the PXI integrated controller through wireless network, the PXI integrated controller is connected with the target control computer through a serial port, and the PXI integrated controller is connected with the deployment management data display unit through a gigabit network cable.

3. The simulation device for automatic detection and tracking of small space objects according to claim 1, characterized in that, After receiving data, an interface function for serial communication between the target control computer and the PXI integrated controller detects whether the RS485 interface is interrupted in real time, stops data transmission task immediately and reports error information to the PXI integrated controller if the data interruption is detected, and the PXI integrated controller issues a next instruction.

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