Space target tracking method based on optical search assembly

Abstract

The invention provides a space target tracking method based on an optical search assembly, and the method specifically comprises the steps: 1, rotating the view field angle of the optical search assembly in a full range, and searching a target object; 2, transmitting a scene in the field of view in real time by the optical search assembly, processing the transmitted scene in the field of view, and judging whether the optical search assembly tracks a target object or not; 3, according to the actual motion trail of the target object, establishing a prediction trail function of the target object, and obtaining a prediction motion trail of the target object; and step 4, rotating the optical search assembly according to the predicted motion track of the target object so as to adjust the view field angle of the optical search assembly.

Description

Technical Field

[0001] The invention relates to the field of aerospace technology, and in particular to a space target tracking method based on an optical search component. Background Art

[0002] Space situational awareness is the foundation for human space activities. Compared with ground-based observation equipment, space-based platforms are not restricted by weather, environment and geopolitical conditions and can observe space targets for a long time. Therefore, space-based space situational awareness has received widespread attention. Among many observation methods, space-based visible light observation has become the main means due to its advantages such as low energy consumption, high reliability and long observation distance.

[0003] At the end of the 20th century, the United States conducted the first space-based visible light observation experiment, placing the space-based observation platform in a sun-synchronous orbit to observe space targets, proving the feasibility and efficiency of visible light observation. In order to further enhance the space situational awareness capability, the United States proposed a strategy of using satellite constellations for collaborative surveillance. Subsequently, Canada also launched the "Sapphire" satellite for space-based surveillance and was incorporated into the US space target surveillance network. Afterwards, the European Space Agency also designed its own space-based visible light observation platform to provide protection for its own space activities. Many practices have proved that the space-based visible light observation platform is very advantageous for monitoring space targets and can well make up for the shortcomings of ground-based observation equipment.

[0004] As space activities become more frequent, effective tracking and monitoring of space targets has become one of the key technologies to ensure space safety, promote scientific research and maintain space order. Therefore, how to track space targets based on optical search components is a technical problem that the present invention needs to solve. Summary of the invention

[0005] The purpose of the present invention is to provide a space target tracking method based on an optical search component, to predict the movement trajectory of the target object, to achieve tracking of the target object, and to improve the working efficiency of the optical search component in tracking the target object.

[0006] In order to achieve the above object, the present invention provides a space target tracking method based on an optical search component. The satellite is provided with an optical search component for tracking the target object. The specific steps include:

[0007] Step 1, rotating the field of view angle of the optical search component throughout the entire range to search for the target object;

[0008] Step 2: The optical search component transmits the scene in the field of view in real time, and processes the transmitted scene in the field of view to determine whether the optical search component tracks the target object;

[0009] Step 3: According to the actual motion trajectory of the target object, a prediction trajectory function of the target object is established to obtain the predicted motion trajectory of the target object;

[0010] Step 4, judging whether the optical search component is rotating according to the predicted motion trajectory of the target object;

[0011] When the predicted motion trajectory of the target object does not leave the field of view of the optical search component, the optical search component does not rotate;

[0012] When the predicted motion trajectory of the target object leaves the field of view of the optical search component, and the target object can appear in the field of view by rotating the optical search component, the optical search component rotates to adjust its field of view angle; when the predicted motion trajectory of the target object leaves the field of view of the optical search component, and the target object cannot appear in the field of view by rotating the optical search component, the optical search component does not rotate.

[0013] Optionally, the optical search component comprises:

[0014] Search the camera and shoot the target object;

[0015] A rotating mechanism, one end of which is fixed on the satellite and the other end of which is fixed on the search camera, driving the search camera to rotate;

[0016] The processor is arranged inside the satellite and transmits signals to the search camera and the rotating mechanism respectively, receives the target image from the search camera, processes the target image, and controls the rotation of the rotating mechanism.

[0017] Optionally, in step 2, the processor processes the scene in the field of view transmitted in real time by the search camera in units of frames.

[0018] Optionally, in step 2, the processor determines whether the target object appears in the frame, and records the determination result of each frame;

[0019] When the processor detects the target object in the current frame, the judgment result is recorded as "detected", and the position information of the target object is recorded, and the processor calculates and obtains the actual spatial coordinates of the target object;

[0020] When the processor does not detect the target object in the current frame, the judgment result is recorded as "not detected", and the judgment results recorded in the previous (n-1) frames corresponding to the frame are searched to see whether they are all "not detected", where n can be set as needed, and n≥3;

[0021] When the judgment results of n consecutive frames are all "not detected", it means that the target object has been lost and the tracking of the target object is exited; when the judgment results of the previous (n-1) frame corresponding to this frame include "detected", it means that the target object has been tracked, and the processing of the current frame is ended, waiting for the processing of the next frame.

[0022] Optionally, in step 3, all frames with a judgment result of "detected" and their corresponding time and actual spatial coordinates of the target object are extracted from the processor, and a target detection set consisting of time and its corresponding actual spatial coordinates is established, and the target detection set is divided into a calculation set and a prediction set; wherein the values ​​of all time elements in the calculation set are smaller than the values ​​of the time elements in the prediction set.

[0023] Optionally, in step 3, the method of establishing a predicted trajectory function of the target object to obtain the predicted motion trajectory of the target object includes:

[0024] Setting a matching threshold of the predicted trajectory of the target object in the processor;

[0025] Perform function fitting on the time in the calculation concentration and its corresponding actual space coordinates to obtain the predicted trajectory function of the target object;

[0026] Substitute the time elements in the prediction set into the prediction trajectory function for calculation, obtain the prediction space coordinates corresponding to the time elements in the prediction set, and use the time elements in the prediction set and the prediction space coordinates obtained by the prediction trajectory function to draw the predicted motion trajectory of the target object; draw the actual motion trajectory of the target object from the time elements in the prediction set and their corresponding actual space coordinates; compare the predicted motion trajectory with the actual motion trajectory of the target object corresponding to the prediction set;

[0027] When the distance between the predicted motion trajectory of the target object and the actual motion trajectory is less than or equal to the matching threshold, the predicted trajectory function can be used to predict the motion trajectory of the target object.

[0028] Optionally, in step 4, when using the predicted trajectory function to determine the predicted spatial coordinates of the target object in the mth frame after the current frame, it is determined whether the predicted spatial coordinates of the target object are outside the field of view of the search camera when the current frame is captured; wherein m≥1;

[0029] When the predicted spatial coordinates of the target object at the mth frame after the current frame calculated by the predicted trajectory function are still within the field of view of the search camera when the current frame is captured, the search camera does not rotate;

[0030] When the predicted spatial coordinates of the target object at the mth frame after the current frame calculated by the predicted trajectory function are not within the field of view of the search camera when the current frame is taken, the processor determines whether the search camera can make the predicted spatial coordinates of the mth frame appear within the field of view of the search camera through the rotation mechanism.

[0031] Optionally, in step 4, when the predicted spatial coordinates still cannot appear in the field of view of the search camera after rotation by the rotation mechanism, the field of view angle of the search camera is not changed, and the tracking of the target object is exited; when the predicted spatial coordinates can appear in the field of view of the search camera after rotation by the rotation mechanism, the processor controls the rotation mechanism to drive the search camera to rotate, and makes the center of the field of view of the search camera and the predicted spatial coordinates of the target object reach the minimum distance.

[0032] Optionally, when the distance between the actual spatial coordinates of the target object in the mth frame after the current frame and the predicted spatial coordinates of the target object in the frame is less than or equal to a matching threshold, the corresponding time in the frame and the actual spatial coordinates of the target object are recorded in the target detection set.

[0033] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0034] The present invention divides the actual spatial coordinates of the target object and its corresponding time into a calculation set and a prediction set, uses the calculation set to establish a predicted trajectory function of the target object, and uses the prediction set to judge the accuracy of the predicted trajectory function, thereby obtaining a predicted trajectory function that can predict the spatial coordinates of the target object; the trajectory of the future movement of the target object is predicted by the predicted trajectory function, and the field of view angle of the search camera is adjusted in advance to achieve tracking of the target object.

[0035] The present invention intelligently determines whether to adjust the field of view angle of the search camera by predicting the spatial coordinates of the target object, thereby avoiding the search camera from searching for the lost target object for a long time and improving the working efficiency of the optical search component in tracking the target object. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the optical search component of the present invention.

[0037] Figure 2 The figure is a flow chart of the space target tracking method based on the optical search component of the present invention.

[0038] In the figure, 1-search camera, 2-rotation mechanism, 3-target object. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] like Figure 1 As shown, the present invention provides an optical search component, which is arranged on a satellite and can capture a target image and process the target image. The optical search component includes: a search camera 1, a rotation mechanism 2 and a processor. The search camera 1 can capture a target object 3 and obtain a target image of the target object 3. One end of the rotation mechanism 2 is fixed on the satellite, and the other end is fixed on the search camera 1, which can drive the search camera 1 to rotate. The processor is arranged inside the satellite, and transmits signals with the search camera 1 and the rotation mechanism 2 respectively, and can receive the target image of the search camera 1, process the target image, control the rotation mechanism 2 to rotate, and make the search camera 1 arranged on the rotation mechanism 2 rotate at the same time, change the relative position of the search camera 1 and the satellite, and then change the field of view range of the target image of the target object 3 captured by the search camera 1.

[0043] like Figure 2 As shown, in order to track the target object 3 in the field of view of the search camera 1, the present invention provides a space target tracking method based on an optical search component, and the specific steps include:

[0044] Step 1: Scan the entire area to search for the target object.

[0045] The search camera 1 on the satellite is rotated 360° by the rotating mechanism 2, so as to change the field of view of the search camera 1 and perform an all-round scan of the scene in front of the satellite.

[0046] Step 2: Confirm the search target and extract the target information.

[0047] The search camera 1 transmits the scene in the field of view to the processor of the satellite in real time during the rotation process, and processes the scene in the field of view transmitted in real time in units of frames. In a preferred embodiment, the time of each frame is 100ms.

[0048] The processor processes each frame to determine whether the target object 3 appears in the frame (ie, the field of view of the current search camera 1), and records the determination result (“detected” or “not detected”) of each frame.

[0049] When the processor detects the target object 3 in the current frame, the judgment result is recorded as "detected", and the position information of the target object is recorded, and the actual spatial coordinates of the target object are calculated by the processor.

[0050] When the processor does not detect the target object 3 in the current frame, the judgment result is recorded as "not detected", and the judgment results recorded in the previous (n-1) frames corresponding to the frame are all "not detected", where n can be set as needed, and n≥3. When the judgment results of n consecutive frames are all "not detected", it means that the target object 3 has been lost, and the tracking of the target object 3 is exited; when the judgment results of the previous (n-1) frames corresponding to the frame include "detected", it means that the target object 3 has been tracked, and the processing of the current frame is terminated, waiting for the processing of the next frame.

[0051] Step 3: Establish a prediction trajectory function of the target object to predict the motion trajectory of the target object.

[0052] The frame in which the target object 3 is detected is further processed to calculate the predicted trajectory of the target object 3.

[0053] All frames with the judgment result of "detected" and their corresponding time and actual space coordinates of the target object 3 are extracted from the processor, and the frames are arranged in time sequence to obtain the actual space coordinate changes of the target object 3 in the time sequence, and then the actual motion trajectory of the target object 3 is obtained, and a target object detection set consisting of time and its corresponding actual space coordinates is established according to the time sequence, and the target object detection set is divided into a calculation set and a prediction set.

[0054] Among them, the numerical values ​​of all time elements in the calculation set are smaller than the numbers of time elements in the prediction set, so that the actual motion trajectory drawn by the calculation set and the actual motion trajectory drawn by the prediction set respectively constitute the first half and the second half of the actual motion trajectory of the target object drawn by the target detection set.

[0055] At the same time, a matching threshold of the predicted trajectory of the target object 3 is set in the processor to determine the accuracy of the predicted motion trajectory of the target object 3 .

[0056] The predicted trajectory function of the target object is obtained by fitting the function of the time elements in the calculation set and the actual space coordinates corresponding to the target object. At the same time, the time elements in the prediction set are substituted into the prediction trajectory function for calculation to obtain the predicted space coordinates corresponding to the time elements in the prediction set, and the predicted motion trajectory of the target object 3 is drawn using the time elements in the prediction set and the predicted space coordinates obtained by the prediction trajectory function; the actual motion trajectory of the target object 3 is drawn using the time elements in the prediction set and the actual space coordinates corresponding to the target object 3; the predicted motion trajectory is compared with the actual motion trajectory of the target object 3 corresponding to the prediction set. When the distance between the predicted motion trajectory of the target object 3 and the actual motion trajectory is less than or equal to the matching threshold, it indicates that the predicted motion trajectory of the target object 3 obtained above successfully matches the actual motion trajectory, and the predicted space coordinates of the target object 3 at a certain subsequent moment can be predicted using the prediction trajectory function; when the distance between the predicted motion trajectory of the target object and the actual motion trajectory is greater than the matching threshold, the training set is re-used to fit the function and the above steps are repeated to obtain a predicted trajectory function that can predict the motion trajectory of the target object 3.

[0057] Step 4: Adjust the field of view of the search camera.

[0058] Using the predicted trajectory function of the target object 3, calculate whether the predicted spatial coordinates of the target object 3 in the future (the mth frame after the current frame, and m≥1 can be set as needed) are outside the field of view of the search camera 1 when shooting the current frame, and whether the field of view angle of the search camera 1 needs to be adjusted, and repeat steps 2-4.

[0059] When the predicted spatial coordinates of the target object 3 at the mth frame after the current frame calculated by the predicted trajectory function are still within the field of view of the search camera 1 when the current frame is captured, the search camera 1 does not rotate. At this time, the processor will process the next frame and repeat steps 2-4.

[0060] When the predicted spatial coordinates of the target object 3 at the mth frame after the current frame calculated by the predicted trajectory function are not within the field of view of the search camera 1 when the current frame is taken, the processor determines whether the search camera 1 can make the predicted spatial coordinates of the mth frame appear within the field of view of the search camera 1 through the rotating mechanism 2.

[0061] When the predicted spatial coordinates still cannot appear in the field of view of the search camera 1 after the rotation of the rotation mechanism 2, the field of view angle of the search camera 1 is not changed, and the tracking of the target object 3 is exited. When the predicted spatial coordinates can appear in the field of view of the search camera 1 after the rotation of the rotation mechanism 2, the processor controls the rotation mechanism 2 to drive the search camera 1 to rotate, and the field of view center of the search camera 1 and the predicted spatial coordinates of the target object 3 reach the minimum distance.

[0062] The processor calculates the predicted spatial coordinates of the target object 3 in the mth frame after the current frame according to the predicted motion trajectory of the target object 3, and adjusts the field of view angle of the search camera 1 according to the predicted spatial coordinates, so that the distance between the predicted spatial coordinates and the adjusted field of view center of the search camera 1 reaches a minimum. At the same time, the processor will process the next frame and repeat steps 2-4.

[0063] Furthermore, when the processor fails to detect the target object 3 in the current frame, and the judgment result of the previous (n-1) frame of the frame is "detected", the processor calculates the predicted spatial coordinates corresponding to the mth frame after the current frame according to the predicted trajectory function, completes the operation in step 4, ends the processing of the current frame, and waits for the next frame.

[0064] Furthermore, when the distance between the actual spatial coordinates of the target object in the mth frame after the current frame and the predicted spatial coordinates of the target object in the frame is less than or equal to the matching threshold, the corresponding time in the frame and the actual spatial coordinates of the target object are recorded in the target detection set. When step 3 is repeated, the predicted trajectory function is updated by updating the target detection set, and the actual spatial coordinates of the target object that deviates too much from the predicted trajectory function are eliminated by using the matching threshold to prevent the target object's motion trajectory from temporarily deviating due to accidental reasons and affecting the accuracy of the predicted trajectory function.

[0065] In summary, the present invention calculates the trajectory of the future movement of the target object by establishing a prediction trajectory function, and then adjusts the field of view angle of the search camera in advance to achieve tracking of the target object.

[0066] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A space target tracking method based on an optical search component, wherein the satellite is provided with an optical search component for tracking a target object, characterized in that: The specific steps include: Step 1, rotating the field of view angle of the optical search component throughout the entire range to search for the target object; Step 2: The optical search component transmits the scene in the field of view in real time, and processes the transmitted scene in the field of view to determine whether the optical search component tracks the target object; Step 3: According to the actual motion trajectory of the target object, a prediction trajectory function of the target object is established to obtain the predicted motion trajectory of the target object; Step 4, judging whether the optical search component is rotating according to the predicted motion trajectory of the target object; When the predicted motion trajectory of the target object does not leave the field of view of the optical search component, the optical search component does not rotate; When the predicted motion trajectory of the target object leaves the field of view of the optical search component, and the target object can appear in the field of view by rotating the optical search component, the optical search component rotates to adjust its field of view angle; when the predicted motion trajectory of the target object leaves the field of view of the optical search component, and the target object cannot appear in the field of view by rotating the optical search component, the optical search component does not rotate.

2. The space target tracking method based on the optical search component according to claim 1, characterized in that: The optical search component comprises: Search the camera and shoot the target object; A rotating mechanism, one end of which is fixed on the satellite and the other end of which is fixed on the search camera, driving the search camera to rotate; The processor is arranged inside the satellite and transmits signals to the search camera and the rotating mechanism respectively, receives the target image from the search camera, processes the target image, and controls the rotation of the rotating mechanism.

3. The space target tracking method based on the optical search component according to claim 2, characterized in that: In the step 2, the processor processes the scene in the field of view transmitted in real time by the search camera in units of frames.

4. The space target tracking method based on the optical search component according to claim 3 is characterized in that: Each frame lasts 100ms.

5. The space target tracking method based on the optical search component according to claim 3, characterized in that: In step 2, the processor determines whether the target object appears in the frame and records the determination result of each frame; When the processor detects the target object in the current frame, the judgment result is recorded as "detected", and the position information of the target object is recorded, and the processor calculates and obtains the actual spatial coordinates of the target object; When the processor does not detect the target object in the current frame, the judgment result is recorded as "not detected", and the judgment results recorded in the previous (n-1) frames corresponding to the frame are searched to see whether they are all "not detected", where n can be set as needed, and n≥3; When the judgment results of n consecutive frames are all "not detected", it means that the target object has been lost and the tracking of the target object is exited; when the judgment results of the previous (n-1) frame corresponding to this frame include "detected", it means that the target object has been tracked, and the processing of the current frame is ended, waiting for the processing of the next frame.

6. The space target tracking method based on the optical search component according to claim 5, characterized in that: In step 3, all frames with a judgment result of "detected" and their corresponding time and actual space coordinates of the target are extracted from the processor, and a target detection set consisting of time and its corresponding actual space coordinates is established, and the target detection set is divided into a calculation set and a prediction set; wherein the values ​​of all time elements in the calculation set are smaller than the values ​​of the time elements in the prediction set.

7. The space target tracking method based on the optical search component according to claim 6, characterized in that: In step 3, the method of establishing a predicted trajectory function of the target object to obtain the predicted motion trajectory of the target object includes: Setting a matching threshold of the predicted trajectory of the target object in the processor; Perform function fitting on the time in the calculation concentration and its corresponding actual space coordinates to obtain the predicted trajectory function of the target object; Substitute the time elements in the prediction set into the prediction trajectory function for calculation, obtain the prediction space coordinates corresponding to the time elements in the prediction set, and use the time elements in the prediction set and the prediction space coordinates obtained by the prediction trajectory function to draw the predicted motion trajectory of the target object; draw the actual motion trajectory of the target object from the time elements in the prediction set and their corresponding actual space coordinates; compare the predicted motion trajectory with the actual motion trajectory of the target object corresponding to the prediction set; When the distance between the predicted motion trajectory of the target object and the actual motion trajectory is less than or equal to the matching threshold, the predicted trajectory function can be used to predict the motion trajectory of the target object.

8. The space target tracking method based on the optical search component according to claim 7, characterized in that: In step 4, when using the predicted trajectory function to determine the predicted spatial coordinates of the target object in the mth frame after the current frame, determine whether the predicted spatial coordinates of the target object are outside the field of view of the search camera when the current frame is captured; wherein m≥1; When the predicted spatial coordinates of the target object at the mth frame after the current frame calculated by the predicted trajectory function are still within the field of view of the search camera when the current frame is captured, the search camera does not rotate; When the predicted spatial coordinates of the target object at the mth frame after the current frame calculated by the predicted trajectory function are not within the field of view of the search camera when the current frame is taken, the processor determines whether the search camera can make the predicted spatial coordinates of the mth frame appear within the field of view of the search camera through the rotation mechanism.

9. The space target tracking method based on the optical search component according to claim 8, characterized in that: In step 4, when the predicted spatial coordinates still cannot appear in the field of view of the search camera after rotation by the rotation mechanism, the field of view angle of the search camera is not changed, and the tracking of the target object is exited; when the predicted spatial coordinates can appear in the field of view of the search camera after rotation by the rotation mechanism, the processor controls the rotation mechanism to drive the search camera to rotate, and makes the center of the field of view of the search camera and the predicted spatial coordinates of the target object reach the minimum distance.

10. The space target tracking method based on the optical search component according to claim 8, characterized in that: When the distance between the actual spatial coordinates of the target object in the mth frame after the current frame and the predicted spatial coordinates of the target object in the frame is less than or equal to the matching threshold, the corresponding time in the frame and the actual spatial coordinates of the target object are recorded in the target detection set.

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