A spatial target tracking method based on optical search components

Abstract

This invention provides a spatial target tracking method based on an optical search component, comprising the following steps: Step 1, rotating the field of view of the optical search component across its entire range to locate the target object; Step 2, transmitting the scene in the field of view in real time from the optical search component, processing the transmitted scene in the field of view, and determining whether the optical search component has tracked the target object; Step 3, establishing a predicted trajectory function for the target object based on its actual motion trajectory to obtain the predicted motion trajectory of the target object; Step 4, rotating the optical search component according to the predicted motion trajectory of the target object to adjust its field of view angle.

Description

Technical Field

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

[0002] Space situational awareness is fundamental to human space activities. Compared to ground-based observation equipment, space-based platforms are not limited by weather, environment, or geographical conditions, and can observe space targets for extended periods. Therefore, space-based situational awareness has received widespread attention. Among various observation methods, space-based visible light observation has become a primary means due to its advantages such as low energy consumption, high reliability, and long observation distance.

[0003] In the late 20th century, the United States conducted its first space-based visible light observation experiment, deploying a space-based observation platform in a sun-synchronous orbit to observe space targets, demonstrating the feasibility and efficiency of visible light observation. To further enhance space situational awareness, the United States proposed a strategy of using satellite constellations for coordinated surveillance. Subsequently, Canada launched the Sapphire satellite for space-based surveillance, which was integrated into the US space target surveillance network. Later, the European Space Agency also designed its own space-based visible light observation platform, providing support for its space activities. Numerous practical applications have proven that space-based visible light observation platforms are highly advantageous for monitoring space targets and can effectively compensate for the shortcomings of ground-based observation equipment.

[0004] With the increasing frequency of space activities, the effective tracking and monitoring of space targets has become one of the key technologies for ensuring space safety, promoting scientific research, and maintaining space order. Therefore, how to track space targets based on optical search components is the technical problem that this invention aims to solve. Summary of the Invention

[0005] The purpose of this invention is to provide a spatial target tracking method based on an optical search component, which predicts the trajectory of the target object, tracks the target object, and improves the efficiency of the optical search component in tracking the target object.

[0006] To achieve the above objectives, this invention provides a space target tracking method based on an optical search component. The satellite is equipped with an optical search component for tracking the target object. The specific steps include:

[0007] Step 1: Rotate the field of view of the optical search component to the full range to locate the target object;

[0008] Step 2: The optical search component transmits the scene in the field of view in real time, processes the scene in the transmitted field of view, and determines whether the optical search component has tracked the target object.

[0009] Step 3: Based on the actual trajectory of the target object, establish a predicted trajectory function for the target object to obtain its predicted trajectory.

[0010] Step 4: Determine whether the optical search component rotates based on the predicted motion trajectory of the target object;

[0011] The optical search component does not rotate if the predicted trajectory of the target object does not leave the field of view of the optical search component.

[0012] When the predicted trajectory of the target object leaves the field of view of the optical search component, and the target object can reappear 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 trajectory of the target object leaves the field of view of the optical search component, and the target object cannot reappear in the field of view by rotating the optical search component, the optical search component does not rotate.

[0013] Optionally, the optical search component includes:

[0014] Search for cameras and photograph the target object;

[0015] The rotating mechanism has one end fixed to the satellite and the other end fixed to the search camera, which drives the search camera to rotate.

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

[0017] Optionally, in step 2, the processor processes the scene within 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 for each frame;

[0019] When the processor detects a target object in the current frame, it records the judgment result as "detected" and records the position information of the target object. The processor then calculates the actual spatial coordinates of the target object.

[0020] When the processor does not detect a target in the current frame, it records the judgment result as "not detected" and searches the previous (n-1) frames to see if the judgment results are all "not detected". Here, n can be set as needed, and n≥3;

[0021] If the judgment result of n consecutive frames is "not detected", it means that the target has been lost and the tracking of the target will be stopped; if the judgment result of the previous (n-1) frames is "detected", it means that the target has been tracked and the processing of the current frame will end, waiting to process the next frame.

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

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

[0024] Set the matching threshold for the predicted trajectory of the target object in the processor;

[0025] By fitting a function to the time in the computation set and its corresponding actual spatial coordinates, the predicted trajectory function of the target object can be obtained.

[0026] Substitute the time elements in the prediction set into the prediction trajectory function to obtain the predicted spatial coordinates corresponding to the time elements in the prediction set. Then, use the time elements in the prediction set and the predicted spatial coordinates obtained through the prediction trajectory function to draw the predicted motion trajectory of the target object. Draw the actual motion trajectory of the target object using the time elements in the prediction set and their corresponding actual spatial 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 trajectory and the actual trajectory of the target object is less than or equal to the matching threshold, the predicted trajectory function can be used to predict the 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 m-th frame after the current frame, it is determined whether the predicted spatial coordinates of the target object are outside the field of view when the search camera captures the current frame; where m≥1;

[0029] When the predicted spatial coordinates of the target object in the m-th frame after the current frame are calculated by the predicted trajectory function and are still within the field of view of the search camera when it captures the current frame, the search camera does not rotate.

[0030] When the predicted spatial coordinates of the target object in the m-th frame after the current frame are not within the field of view of the search camera when the current frame is captured, the processor determines whether the search camera can make the predicted spatial coordinates of the m-th frame appear within the field of view of the search camera by rotating the mechanism.

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

[0032] Optionally, if the distance between the actual spatial coordinates of the target object in the m-th frame after the current frame and the predicted spatial coordinates of the target object in that frame is less than or equal to the matching threshold, then the corresponding time and the actual spatial coordinates of the target object in that frame are recorded in the target object detection set.

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

[0034] This invention divides the actual spatial coordinates of the target object into a calculation set and a prediction set based on its corresponding time. The calculation set is used to establish a predicted trajectory function for the target object, and the prediction set is used to determine the accuracy of the predicted trajectory function, thereby obtaining a predicted trajectory function that can predict the spatial coordinates of the target object. The predicted trajectory function is used to predict the future trajectory of the target object, thereby adjusting the field of view angle of the search camera in advance to achieve target object tracking.

[0035] This invention intelligently determines whether to adjust the field of view of the search camera by predicting the spatial coordinates of the target object, thereby avoiding the search camera from searching for a target object that has been lost for a long time and improving the working efficiency of the optical search component in tracking the target object. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the optical search component of the present invention.

[0037] Figure 2 This is a flowchart of the spatial target tracking method based on an optical search component according to the present invention.

[0038] In the diagram, 1-search camera, 2-rotating mechanism, 3-target object. Detailed Implementation

[0039] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] like Figure 1 As shown, this invention provides an optical search component, mounted on a satellite, capable of capturing and processing target images. The optical search component includes a search camera 1, a rotation mechanism 2, and a processor. The search camera 1 captures images of a target object 3. One end of the rotation mechanism 2 is fixed to the satellite, and the other end is fixed to the search camera 1, enabling the search camera 1 to rotate. The processor is located inside the satellite and transmits signals to both the search camera 1 and the rotation mechanism 2. It receives and processes the target images from the search camera 1, controls the rotation mechanism 2 to rotate, and simultaneously rotates the search camera 1 mounted on the rotation mechanism 2, changing the relative position of the search camera 1 to the satellite, thereby altering the field of view of the target image captured by the search camera 1.

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

[0044] Step 1: Full-range scan to search for the target object.

[0045] The rotating mechanism 2 enables the search camera 1 on the satellite to rotate 360°, changing the field of view of the search camera 1 and performing an all-round scan of the scene in front of the satellite.

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

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

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

[0049] When the processor detects target object 3 in the current frame, it records the judgment result as "detected" and records the position information of the target object. The processor then calculates the actual spatial coordinates of the target object.

[0050] When the processor does not detect target 3 in the current frame, it records the judgment result as "not detected". Simultaneously, it searches the previous (n-1) frames to see if all judgment results are "not detected", where n can be set as needed, and n≥3. If the judgment results for n consecutive frames are all "not detected", it indicates that target 3 has been lost, and tracking of target 3 is terminated. If the judgment results for the previous (n-1) frames contain "detected", it indicates that target 3 has been tracked, and processing of the current frame ends, awaiting the next frame.

[0051] Step 3: Establish the target object's predicted trajectory function to predict the target object's motion trajectory.

[0052] For frames where target object 3 is detected, further processing is performed to calculate the predicted trajectory of target object 3.

[0053] Extract all frames with a judgment result of "detected" from the processor, along with their corresponding time and the actual spatial coordinates of the target object 3. Arrange the frames in chronological order to obtain the changes in the actual spatial coordinates of the target object 3 in the chronological order, thereby obtaining the actual motion trajectory of the target object 3. Establish a target object detection set based on the chronological order, consisting of time and its corresponding actual spatial coordinates. Divide the target object detection set into a calculation set and a prediction set.

[0054] In this case, the values ​​of all time elements in the computation set are less than the values ​​of the time elements in the prediction set, so that the actual motion trajectory drawn by the computation set and the actual motion trajectory drawn by the prediction set constitute the first half and the second half of the actual motion trajectory of the target object drawn by the target object detection set, respectively.

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

[0056] A predicted trajectory function for the target object is obtained by fitting a function to the time elements in the computation set and their corresponding actual spatial coordinates. Simultaneously, the time elements in the prediction set are substituted into the predicted trajectory function for calculation to obtain the predicted spatial coordinates corresponding to the time elements in the prediction set. The predicted motion trajectory of target object 3 is then plotted using the time elements in the prediction set and the predicted spatial coordinates obtained through the predicted trajectory function. The actual motion trajectory of target object 3 is plotted using the time elements in the prediction set and their corresponding actual spatial coordinates. This predicted motion trajectory is then compared with the actual motion trajectory of target object 3 corresponding to the prediction set. When the distance between the predicted motion trajectory and the actual motion trajectory of target object 3 is less than or equal to the matching threshold, it indicates that the predicted motion trajectory of target object 3 has successfully matched the actual motion trajectory, and the predicted spatial coordinates of target object 3 at a subsequent moment can be predicted using the predicted trajectory function. When the distance between the predicted motion trajectory and the actual motion trajectory of target object 3 is greater than the matching threshold, the function is fitted again using the training set, and the above steps are repeated to obtain a predicted trajectory function capable of predicting the motion trajectory of target object 3.

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

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

[0059] When the predicted spatial coordinates of target object 3 in the m-th frame after the current frame, calculated using the trajectory prediction function, are still within the field of view of search camera 1 when it captured the current frame, 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 in the mth frame after the current frame are not within the field of view of the search camera 1 when the current frame is captured by the predicted trajectory function, the processor determines whether the search camera 1 can make the predicted spatial coordinates of the mth frame appear in the field of view of the search camera 1 by rotating the mechanism 2.

[0061] If the predicted spatial coordinates still cannot appear within the field of view of the search camera 1 after rotation via the rotating mechanism 2, the field of view angle of the search camera 1 remains unchanged, and tracking of the target object 3 is discontinued. If the predicted spatial coordinates can appear within the field of view of the search camera 1 after rotation via the rotating mechanism 2, the processor controls the rotating mechanism 2 to rotate the search camera 1, and minimizes the distance between the center of the field of view of the search camera 1 and the predicted spatial coordinates of the target object 3.

[0062] The processor calculates the predicted spatial coordinates of target 3 in the m-th frame after the current frame based on the predicted motion trajectory of target 3, and adjusts the field of view angle of search camera 1 according to the predicted spatial coordinates to minimize the distance between the predicted spatial coordinates and the adjusted field of view center of search camera 1. Simultaneously, the processor processes the next frame and repeats steps 2-4.

[0063] Furthermore, if the processor does not detect target 3 in the current frame, and the judgment result of the previous (n-1) frames is "detected", the processor calculates the predicted spatial coordinates of the m-th frame after the current frame according to the predicted trajectory function, completes the operation described in step 4, and ends the processing of the current frame, waiting for the next frame.

[0064] Furthermore, if the distance between the actual spatial coordinates of the target object in the m-th frame after the current frame and the predicted spatial coordinates of the target object in that frame is less than or equal to the matching threshold, then the corresponding time and the actual spatial coordinates of the target object in that frame are recorded in the target object detection set. When step 3 is repeated, the predicted trajectory function is updated by updating the target object detection set, and the actual spatial coordinates of the target object that deviate excessively from the predicted trajectory function are removed using the matching threshold to prevent the accuracy of the predicted trajectory function from being affected by a temporary deviation in the target object's trajectory due to accidental reasons.

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

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

Claims

1. A space object tracking method based on an optical search assembly, an optical search assembly is provided on a satellite for tracking a target object, characterized in that, The specific steps include: Step 1, full-range rotation of the field of view angle of the optical search assembly to find the target object; Step 2, real-time transmission of the scene in the field of view by the optical search assembly, processing of the transmitted scene in the field of view, and determination of whether the optical search assembly tracks the target object; Processing of the real-time transmitted scene in the field of view by the optical search assembly in frames, and determination of whether the target object appears in the frame; when the optical search assembly 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 actual spatial coordinates of the target object are calculated by the optical search assembly; Step 3, establishment of a prediction trajectory function of the target object according to the actual motion trajectory of the target object, and obtaining of the predicted motion trajectory of the target object; Extraction of all frames with the judgment result of "detected" and their corresponding time and actual spatial coordinates of the target object from the optical search assembly, establishment of a target object detection set composed of time and its corresponding actual spatial coordinates, and division of the target object detection set into a calculation set and a prediction set; wherein the numerical value of all time elements in the calculation set is less than that of the time elements in the prediction set; Setting of a matching threshold of the predicted trajectory of the target object in the optical search assembly; Function fitting of the time and its corresponding actual spatial coordinates in the calculation set to obtain the prediction trajectory function of the target object; Calculation of the time elements in the prediction set by substituting them into the prediction trajectory function to obtain the predicted spatial coordinates corresponding to the time elements in the prediction set, and drawing of the predicted motion trajectory of the target object by using the time elements in the prediction set and the predicted spatial coordinates obtained by the prediction trajectory function; drawing of the actual motion trajectory of the target object by using the time elements in the prediction set and their corresponding actual spatial coordinates; comparison of 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 and the actual motion trajectory of the target object is less than or equal to the matching threshold, the prediction trajectory function can be used to predict the motion trajectory of the target object; Step 4, determination of whether the optical search assembly rotates 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 assembly, the optical search assembly does not rotate; When the predicted motion trajectory of the target object leaves the field of view of the optical search assembly, and the target object can appear in the field of view by rotating the optical search assembly, the optical search assembly rotates to adjust the field of view angle; when the predicted motion trajectory of the target object leaves the field of view of the optical search assembly, and the target object cannot appear in the field of view by rotating the optical search assembly, the optical search assembly does not rotate.

2. The space object tracking method based on an optical search assembly according to claim 1, characterized in that, The optical search assembly includes: A search camera for photographing the target object; A rotating mechanism with one end fixed on the satellite and the other end fixed on the search camera to drive the search camera to rotate; A processor arranged in the satellite and in signal transmission with the search camera and the rotating mechanism to receive the target image of the search camera, process the target image, and control the rotation of the rotating mechanism.

3. The space object tracking method based on an optical search assembly according to claim 2, characterized in that, The time of each frame is 100 ms.

4. The space object tracking method based on an optical search assembly according to claim 2, characterized in that, In step 2, when the processor determines that the target object does not appear in the frame, the determination result is recorded as "not detected", and whether the determination results recorded in the previous (n-1) frames corresponding to the frame are all "not detected" is searched, wherein n can be set according to the needs, and n≥3. When the determination results of the continuous n frames are all "not detected", it indicates that the target object has been lost, and the tracking of the target object is exited; when the determination results of the previous (n-1) frames corresponding to the frame exist "detected", it indicates that the target object has been tracked, and the processing of the current frame is ended, and the next frame is waited to be processed.

5. The space object tracking method based on optical search assembly according to claim 2, characterized in that, In step 4, when the target object prediction space coordinates of the m-th frame after the current frame are determined by using the prediction trajectory function, whether the prediction space coordinates of the target object are outside the field of view when the search camera shoots the current frame is determined; wherein m≥1. When the target object prediction space coordinates of the m-th frame after the current frame calculated by the prediction trajectory function are still inside the field of view when the search camera shoots the current frame, the search camera does not rotate. When the target object prediction space coordinates of the m-th frame after the current frame calculated by the prediction trajectory function are not inside the field of view when the search camera shoots the current frame, whether the search camera can make the prediction space coordinates of the m-th frame appear in the field of view of the search camera by the rotating mechanism is determined by the processor.

6. The space object tracking method based on an optical search assembly according to claim 5, characterized in that, In step 4, when the prediction space coordinates still cannot appear in the field of view of the search camera after the rotating mechanism rotates, the field angle of the search camera is not changed, and the tracking of the target object is exited; when the prediction space coordinates can appear in the field of view of the search camera after the rotating mechanism rotates, the rotating mechanism is controlled by the processor to drive the search camera to rotate, and the field center of the search camera and the prediction space coordinates of the target object reach the minimum distance.

7. The space object tracking method based on an optical search assembly according to claim 5, characterized in that, When the distance between the actual space coordinates of the target object in the m-th frame after the current frame and the prediction space coordinates of the target object in the m-th frame is less than or equal to the matching threshold, the corresponding time and the actual space coordinates of the target object in the frame are recorded to the target object detection set.

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