A method for planning a cooperative search and tracking task of a heterogeneous constellation of payloads equipped with gimbals

Abstract

The application discloses a kind of equipment turntable load heterogeneous star group cooperative search and tracking task planning method.For non-cooperative time-sensitive target search and tracking problem, the application is based on the static orbit satellite and low-orbit star group of configuration turntable load, and the star group online cooperative application strategy of regional search, target tracking and identification confirmation is proposed.The rotating jamming method and parallel strip disassembly are used to realize the folding back scan coverage of static orbit satellite to large area.The safety range of time-sensitive target is set, and the positive hexagonal neighborhood transfer strategy is used to realize the continuous tracking of static orbit satellite to target.The potential accessibility screening and approximate vertical over-the-top observation strategy are used to realize the relay identification confirmation of low-orbit star group to fuzzy time-sensitive target.Then, a contract network task planning method suitable for heterogeneous star group is designed, so that the star group has autonomous search capability and can cope with sudden target loss situation.Finally, scene simulation shows that the method of the application can complete the effective excavation and long-term monitoring of time-sensitive target in suspicious area.

Description

Technical Field

[0001] This invention belongs to the field of mission planning technology, specifically relating to a mission planning method for heterogeneous constellation cooperative search and tracking equipped with a turntable payload. Background Technology

[0002] Highly dynamic, multi-mission collaborative application scenarios such as disaster relief and emergency observation, multi-regional continuous monitoring, and multi-target fine-grained detection missions place higher demands on the wide-area coverage and high-resolution detailed reconnaissance capabilities of spacecraft. Low-Earth orbit (LEO) satellites have a small field of view and a short visible window, making it difficult to observe large areas and continuously track time-sensitive targets. While geostationary orbit (GEO) satellites possess a very large field of view and extremely high coverage capabilities, their observation resolution is low and their maneuvering time is long, making it difficult to achieve fine-grained target observation. Furthermore, GEO satellite orbital resources are extremely scarce, making it impossible to deploy multiple satellites in close proximity. Therefore, using turntables to equip additional payloads on individual GEO satellites expands the boundaries of observation capabilities. Combining GEO satellites with LEO constellations fully leverages their respective observational advantages, compensates for capability deficiencies, and forms a heterogeneous constellation reconnaissance system to address the needs of searching and tracking non-cooperative time-sensitive targets. As constellation size increases, mission planning models and frameworks for single satellites and small-scale constellations are no longer applicable. Therefore, how to design heterogeneous constellation collaborative modes and rationally plan satellite missions has become a key and challenging aspect of improving constellation observation efficiency and reconnaissance capabilities.

[0003] Many scholars and institutions have conducted in-depth research on the problem of heterogeneous constellation mission planning. Zhou et al. designed a hybrid method of heterogeneous constellation scheduling and mission planning based on dynamic programming and improved contract network algorithms for emergency insertion of fixed-point targets and cooperative moving targets, achieving continuous observation of targets. Ben et al. designed a decentralized replanning method for homogeneous or heterogeneous constellations for ground dynamic events, shortening constellation mission response time. Lorenzo et al. adopted a multi-satellite system with heterogeneous orbits and payloads for large-area applications, simulated mission and satellite compatibility based on hypergraphs, and used mixed-integer linear programming to complete mission allocation. Du et al. established an evolvable constellation intelligent mission planning engine architecture to meet the needs of point group, multi-frequency, and large-area observation, realizing observation strategy generation and constellation observation scheduling. Kim et al. used SAR satellites and electro-optical satellites flying in heterogeneous formations to achieve continuous observation of the same target and analyzed the scheduling performance and computational load of different constellation configurations. Zhao et al. designed an asymmetric traveling salesman model for scheduling observation tasks in heterogeneous low-Earth orbit constellations and used the Lin-Kernighan-Helsgaun algorithm to solve the problem, improving scheduling efficiency and scalability. Wang et al. designed a multi-agent distributed task management model for heterogeneous low-Earth orbit constellations, achieving constellation event detection, dynamic task allocation, and real-time optimization. He et al. designed multi-objective optimization indices and constraints for a hybrid constellation of high, medium, and low-Earth orbits to address global census and regional detailed survey problems. Samuel et al., based on a large neighborhood search algorithm, used 16 low-Earth orbit satellites to achieve complex requirements such as target positioning, regular observation, and multi-angle observation. Wu et al., based on a parallel genetic particle swarm optimization algorithm, used a non-co-orbiting low-Earth orbit remote sensing constellation to achieve high-efficiency and low-cost coverage of large areas. Zhao et al. established a collaborative search model between LEO and GEO satellites for missing ships, and based on a bilevel metaheuristic algorithm, achieved attitude path and time window planning. However, most of these methods are limited to small-scale constellations or constellations at a specific orbital altitude. In terms of constellation applications, the task scenarios are relatively simple, lacking a collaborative mechanism design for constellation-based regional search and time-sensitive target tracking. Regarding task planning, there is a lack of planning for motion state perception of targets without prior information.

[0004] To address the limitations of previous studies that lacked multi-method collaborative modes, this invention designs a heterogeneous constellation of geostationary and low-Earth orbit satellites equipped with a turntable payload. By combining wide-area coverage with detailed local surveys, research was conducted on online collaborative mission planning for the constellation, including regional search, target tracking, and identification confirmation. This provides a flexible and feasible solution for the search and tracking of non-cooperative time-sensitive targets. Summary of the Invention

[0005] This invention provides a method for planning heterogeneous constellation cooperative search and tracking missions equipped with a turntable payload, addressing the problem of non-cooperative time-sensitive target search and tracking.

[0006] This invention is achieved through the following technical solution: A method for planning a heterogeneous constellation cooperative search and tracking mission equipped with a turntable payload, the planning method comprising the following steps: Step 1: The geostationary satellite, acting as the evaluator, receives ground requests and searches for suspicious areas based on a folded backscan strategy. If no target is found, the search ends; if a target is found, the search begins. Step 2: The geostationary satellite locks onto the time-sensitive target and calculates its trajectory. When the low-orbit satellite enters the field of view, a tender document is prepared based on the latest acquisition information, and an observation tender is issued to the low-orbit satellite constellation. Step 3: Low-Earth orbit (LEO) satellites generate identification schemes based on accessibility screening and submit bids; geostationary orbit (GEO) satellites comprehensively evaluate the various schemes, select the best winning satellite, and announce the results. Step 4: The winning low-orbit satellite performs target identification and confirmation tasks and directly feeds back the detailed investigation results to the ground user, completing the closed loop.

[0007] Furthermore, step 1 specifically includes the following steps: Step 1.1: The geostationary satellite, acting as the assessor, receives observation requests from ground users for the suspected area; Step 1.2: The geostationary satellite payload generates a region search task based on the folding back scan strategy; after the search is completed, the task execution results are sent to the ground user; if no time-sensitive target is found, the current round of the task ends; if a time-sensitive target is found, proceed to the next step. Step 1.3: The geostationary satellite turntable payload generates a non-cooperative time-sensitive target tracking task based on a neighborhood transfer strategy; during the tracking process, the task execution results are sent to the ground user; Furthermore, step 2 specifically involves the geostationary satellite locating the time-sensitive target. When a low-orbit satellite enters the coverage area of ​​the geostationary satellite, the geostationary satellite generates a tender document and issues it to the low-orbit satellite, thus completing the contract network bidding. The tender content is based on the constellation mission planning model and can be represented as the geostationary satellite's most recent acquisition information of the time-sensitive target.

[0008] Furthermore, step 3 specifically includes the following steps: Step 3.1: The low-Earth orbit satellite constellation receives tender documents, generates identification and confirmation tasks based on the accessibility screening strategy, submits the task plan to the geostationary orbit satellite, and completes the online bidding for the contract; Step 3.2: After receiving all mission proposals from low-Earth orbit satellites within its coverage area or after the proposal submission deadline, the geostationary satellite evaluates the proposals. Step 3.3: The geostationary satellite will sort the scores of the mission proposals in this round from largest to smallest, select the satellite belonging to the mission proposal with the highest score as the execution satellite, and announce the contract network bidding results; Furthermore, step 4 specifically involves the winning low-orbit satellite performing the task of identifying and confirming time-sensitive targets and feeding back the observation results to ground users.

[0009] A heterogeneous constellation cooperative search and tracking mission planning system equipped with a turntable payload, the planning system employing the aforementioned heterogeneous constellation cooperative search and tracking mission planning method equipped with a turntable payload, the planning system comprising, Demand response and area search module: The geostationary satellite, acting as the evaluator, receives ground requests and searches for suspicious areas based on the folded backscan strategy. If no target is found, the search ends; if a target is found, the search begins. Target positioning and mission bidding module: The geostationary satellite locks onto the time-sensitive target and calculates its trajectory. When the low-orbit satellite enters the field of view, it generates a bid based on the latest acquisition information and issues an observation bid to the low-orbit satellite constellation. Scheme evaluation and awarding module: Low-Earth orbit satellites generate identification schemes based on accessibility screening and submit bids; Geostationary orbit satellites comprehensively evaluate all schemes, select the best satellite and announce the results; Mission execution and closed-loop module: The winning low-orbit satellite performs target identification and confirmation tasks and directly feeds back the detailed investigation results to the ground user, thus completing the closed loop.

[0010] The beneficial effects of this invention are: This invention designs a dynamic collaborative application mode and mission planning model for high time-sensitive target tracking and observation missions and heterogeneous constellations combining geostationary orbit and low-Earth orbit satellites with turntable payloads, in the event of emergency loss.

[0011] This invention proposes a hybrid method combining the rotating chuck method and parallel strip disassembly, along with a regular hexagonal neighborhood transfer strategy. This enables the geostationary satellite payload to fold and scan over large areas while simultaneously achieving flexible and continuous target tracking by the geostationary satellite turntable payload.

[0012] This invention employs a potential accessibility screening and near-vertical overhead observation strategy to achieve relay identification and confirmation of ambiguous time-sensitive targets by low-Earth orbit constellations. Ultimately, it realizes efficient collaborative task planning throughout the entire process of searching, tracking, losing, finding, and re-tracking non-cooperative time-sensitive targets by heterogeneous constellations. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention.

[0014] Figure 2 This is a diagram showing the installation of the geostationary satellite payload of the present invention.

[0015] Figure 3 This is a diagram illustrating the satellite mission execution scenario of this invention.

[0016] Figure 4 This is a diagram showing the switching modes of the star cluster application of the present invention.

[0017] Figure 5 This is an exploded view of the parallel stripes in the region of this invention.

[0018] Figure 6 This is a static orbit satellite folding back scan observation image of the present invention.

[0019] Figure 7 This is a projection diagram of the turntable load in the equatorial plane in the power-on state of the present invention.

[0020] Figure 8 This is a schematic diagram of the safety range and neighborhood of the present invention.

[0021] Figure 9 This is a schematic diagram of the target motion trajectory under extreme conditions according to the present invention.

[0022] Figure 10 This is a satellite accessibility calculation diagram for the target according to the present invention.

[0023] Figure 11 This is an approximate vertical overhead observation image of the target by a low-orbit satellite according to the present invention.

[0024] Figure 12 This is a flowchart of the heterogeneous constellation-based task planning process of the present invention.

[0025] Figure 13 This is the region and time-sensitive target map of the present invention.

[0026] Figure 14 This is a diagram showing the attitude and imaging time period of the GEO satellite body according to the present invention.

[0027] Figure 15 This is a diagram showing the path and area coverage of the load pointing point of the present invention.

[0028] Figure 16 This is a diagram showing the coverage of the potential range of the initial loss location by the body load of the present invention.

[0029] Figure 17 This is a schematic diagram illustrating the coverage of the potential range of the second lost location by the body load of the present invention.

[0030] Figure 18 This is a diagram showing the attitude and imaging time period of the GEO satellite turntable payload in this invention.

[0031] Figure 19 This is a schematic diagram of the pointing point path for the first round of continuous tracking of the turntable load according to the present invention.

[0032] Figure 20 This is a schematic diagram of the pointing point path for the second round of continuous tracking of the turntable load in this invention.

[0033] Figure 21 This is a schematic diagram illustrating the coverage of the turntable load on the time-sensitive target according to the present invention.

[0034] Figure 22 This is a diagram showing the attitude and imaging time period of a low-orbit satellite mission according to the present invention.

[0035] Figure 23 This is the observation scenario of a time-sensitive target by a low-orbit satellite according to the present invention.

[0036] Figure 24 This describes the coverage of time-sensitive targets by the low-orbit constellation of the present invention.

[0037] Figure 25 This is a path diagram of the GEO satellite payload pointing point of the present invention.

[0038] Figure 26 This is a map showing the coverage of the low-orbit constellation region according to the present invention.

[0039] Figure 27 This is the path diagram of the payload pointing point of the GEO satellite turntable of the present invention. Detailed Implementation

[0040] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0041] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0042] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0043] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0044] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0045] Implementation Method 1 This embodiment provides a heterogeneous constellation collaborative search and tracking mission planning method equipped with a turntable payload. When dealing with large areas and highly time-sensitive targets, relying solely on a single satellite is insufficient for effective target situational awareness. Heterogeneous constellations can leverage their comprehensive orbital types, abundant payload resources, and efficient collaborative capabilities to complete mission planning for complex observation needs. In this model, the constellation members are divided into one geostationary orbit satellite and several low-Earth orbit (LEO) satellites based on their orbital altitude. The geostationary satellite carries two low-resolution infrared payloads. The first payload, directly fixed to the satellite body (called the main payload), is used for the search mission. The second payload, mounted via a turntable (called the turntable payload), is used for the tracking mission. Both the satellite body and the turntable possess independent maneuverability. Therefore, the geostationary satellite can achieve simultaneous coarse positioning of two targets over a very large area. The LEO satellite carries a high-resolution visible light payload, which is fixedly mounted to the satellite body. Because the LEO satellite's orbital altitude is much lower than that of the geostationary satellite, its visible range is smaller, making it difficult to capture targets with unknown geographic information, but its imaging quality is far superior to that of the geostationary satellite.

[0046] The targets to be observed in this model can be divided into regional targets and time-sensitive targets. The geographical locations of regional targets are known information. Time-sensitive targets, however, are non-cooperative targets; their trajectories cannot be obtained in advance by the constellation and must be captured through observation missions.

[0047] Star cluster application scenarios such as Figure 1 As shown, the user first selects an area where time-sensitive targets may exist (such as ports, airports, bases, etc.), and then the constellation calls upon geostationary orbit satellites to scan and search the area. Once a time-sensitive target (such as a ship, aircraft, or vehicle) is detected, the geostationary orbit satellites continuously track the target and send positioning information to low-Earth orbit satellites. The low-Earth orbit satellites then perform close-range, high-resolution observations of the time-sensitive target based on its real-time location to identify and confirm the target type.

[0048] Cluster mission planning model The input to the constellation mission planning model includes geostationary orbit satellite parameters, low Earth orbit satellite parameters, and regional geographic parameters. The model variable is the actual trajectory of the time-sensitive target. The constellation mission planning algorithm must, within limited resources, rationally select satellite observation windows and imaging attitudes to achieve efficient collaborative observation of the target by the constellation. Finally, the model output includes the constellation mission set and the time-sensitive target acquisition trajectory. Their notation is as follows: (1) Geostationary satellite

[0049] in, express The orbital parameters are described using position and velocity at any given time or the orbital six-element number. express The maximum maneuver angle of the main body. This indicates the angular velocity of the main body's maneuver. This indicates the width of the load on the main body. This indicates the maximum rotation angle of the turntable. This indicates the angular velocity of the turntable's movement. This indicates the load width of the turntable. This represents the vector from the origin of the turntable within the satellite's internal structure to the turntable's payload mounting point. The payload mounting configuration is as follows: Figure 2 As shown. The payload mounting point is located at the satellite's center of mass, and the optical axis is aligned with the satellite's mainframe. The axes coincide. The turntable load has dual-degree-of-freedom maneuverability in the roll and pitch directions. In the initial state, the coordinate axes of the turntable load system and the satellite system are in the same direction.

[0050] (2) Low Earth Orbit Satellite Set

[0051] in, Indicates the first star in the star cluster A low-orbit satellite. express The set of orbits. express The maximum maneuver angle of the main body. This indicates the angular velocity of the maneuver. This indicates the maximum boot time per session.

[0052] (3) Region

[0053] in, The first region One vertex, Indicates the latitude of the vertex. This indicates the longitude of the vertices, which are arranged in a clockwise direction.

[0054] (4) Cluster Mission Collection

[0055] Satellite mission execution scenarios such as Figure 3 As shown. Among them, Indicates the satellite sequence number to be executed. This indicates that the mission will be carried out by a geostationary satellite. This indicates that the mission will be carried out by a low-Earth orbit satellite. Indicates the start time of the task. Indicates the load start-up time. Indicates the moment the load is shut down. Indicates the end time of the task. This represents the set of attitude parameters of the satellite itself. This represents the turntable attitude set. When the mission is performed by a low-Earth orbit satellite... Empty.

[0056] (5) Time-sensitive target acquisition track

[0057] in, The first one represents the target One capture point, Indicates the moment of capture. Indicates the latitude of the capture point. Indicates the longitude of the capture point. Indicates the capture point height. The capture point velocity.

[0058] Dynamic collaborative application mode To facilitate the establishment of constellation application scenarios, this invention first makes the following assumptions: (1) The constellation members have onboard image processing capabilities. The infrared payloads carried by geostationary satellites can identify the target's position and velocity information, while the visible light payloads carried by low-Earth orbit satellites can identify the target's physical characteristics.

[0059] (2) The constellation has inter-satellite and satellite-to-ground links, and any member can directly or indirectly transmit data to other members and ground stations to achieve information sharing.

[0060] The constellation is divided into three collaborative application modes based on its observation purpose: regional search, target tracking, and identification / confirmation. Each time a satellite performs a mission, it must feed back the observation results to the constellation. The constellation then autonomously and dynamically switches application modes according to the collaborative strategy. The switching process is as follows: Figure 4 As shown.

[0061] (1) Area search This mode is suitable for regional observation missions without clear prior information, aiming to detect the presence of suspicious targets within the area. The demand for regional searches comes from both active requests and passive triggers. Active requests involve users directly selecting an area for observation, while passive triggers occur in complex and uncertain environments when time-sensitive targets are lost, triggering emergency searches of the affected area. For large areas, low-Earth orbit satellites have short visibility windows and limited fields of view, making it impossible to achieve effective observation of the area in a single mission. Therefore, a folded backscan of the geostationary orbit satellite's payload is used to achieve complete coverage. During the search, once a time-sensitive target is detected within the area, the satellite immediately transmits the target's motion information to the constellation, which then switches to target tracking mode. If no target is detected during the search, the mission ends.

[0062] (2) Target tracking This mode is suitable for motion state perception of non-cooperative time-sensitive targets. After a time-sensitive target is discovered through a regional search, the constellation is required to continuously observe the target. Therefore, a geostationary satellite turntable payload is used to track the target based on a neighborhood transfer strategy, outputting the target's position and velocity information in real time. After successful target acquisition, the constellation calls upon other satellites to synchronously identify and confirm the target. During tracking, cloud cover or sea state interference may occur, affecting the imaging quality of the optical payload and causing the satellite to lose the target. In this case, a potential region is generated centered on the target's last acquisition position based on the target's velocity. Subsequently, the constellation switches to regional search mode to attempt to recover the lost time-sensitive target.

[0063] (3) Identification and Confirmation This mode is suitable for the rapid identification of ambiguous time-sensitive targets with unknown physical properties but available location information. Therefore, the constellation uses low-Earth orbit (LEO) satellites based on accessibility screening and near-vertical overhead observation strategies to perform close-range, high-resolution imaging of the target. If the time-sensitive target is confirmed to be a high-value target (such as a warship or fighter jet), the geostationary orbit (GEO) satellites maintain target tracking, while the LEO satellites continuously identify and confirm the target, outputting target location information and images. If the time-sensitive target is a common target (such as a fishing boat or passenger aircraft), the mission ends.

[0064] Geostationary satellite payload region search strategy based on folded back scan When using a geostationary satellite's payload to search a large area, the payload swath width is much smaller than the area width. Therefore, the geostationary satellite needs to perform repeated scans of the area through attitude maneuvers, forming multiple strips on the ground. Only after these strips are stitched together can complete coverage of the area be achieved. To address this, the payload coverage area is first determined based on the area's geographic information. Then, the key attitude parameters of the satellite during the mission are calculated based on the scanning method, ultimately yielding the geostationary satellite mission parameters.

[0065] (1) Solving the load coverage area For user-submitted polygon region search requests, the rotating caliper algorithm is used to solve for the minimum area bounding rectangle of the region as the coverage result, minimizing satellite maneuvering and payload working time, and improving mission execution efficiency.

[0066] The region The average longitude of the vertex is used as the reference longitude. . Any vertex according to Depend on Transform to Gaussian coordinates, denoted as .in, for The x-coordinate in a Gaussian coordinate system for The ordinate in the Gaussian coordinate system.

[0067] According to the rotating caliper algorithm, a convex polygon and its minimum area circumscribed rectangle must have a common edge

[19] . The number of vertices is denoted as The computational complexity of the rotating caliper algorithm is then... Traversal For each edge, calculate the slope of each edge. .

[0068] (1) Select a reference edge (slope is) After that, proceed through each vertex in turn. Draw a line parallel to and perpendicular to the reference side. The rectangular outer envelope of the region is obtained. The expression for the upper envelope along the direction parallel to the reference edge is: (2) The expression for the lower envelope along the direction parallel to the reference edge is: (3) The expression for the upper envelope in the direction perpendicular to the reference edge is: (4) The expression for the lower envelope in the direction perpendicular to the reference edge is: (5) In the formula, It is a function with maximum value. This is the minimum value function. Therefore, the side length of the circumscribed rectangle parallel to the reference side is obtained as follows. The length of the side perpendicular to the reference side is .

[0069] (6) (7) The area of ​​the circumscribed rectangle is By traversing each edge and substituting into equations (1) to (7), the circumscribed rectangle with the smallest area can be obtained. Then, the intersection of any two envelope lines is calculated, which are the vertices of the circumscribed rectangle of the region, denoted as […]. , , , ,like Figure 5 As shown.

[0070] For emergency search needs arising from the loss of time-sensitive targets, the potential target area is a circular region, with the center of the circle being the target's last captured location. ,in Number of times the target was captured. Radius It can be obtained from the target's historical maximum acquisition speed, loss time, and satellite's maximum maneuver time.

[0071] (8) In the formula, This is the range coefficient, typically set between 1.2 and 1.8, to ensure the search range sufficiently covers the movement range of the time-sensitive target. This refers to the current moment.

[0072] Since all the bounding rectangles of the circular region have the same area, the bounding rectangle whose two sides coincide with the Gaussian coordinate axis is directly selected as the load coverage area.

[0073] (2) Satellite attitude solution The satellite body employs a folded back-scan method to achieve complete coverage of the region by its payload. Along the long side of the circumscribed rectangle, the area is uniformly divided into several strips according to the width of the payload. Let... , Then the number of stripes With strip width They are respectively: , (9) In the formula, This is the floor function. This method allows for slight overlap between adjacent strips, thus ensuring seamless observation of the region using a minimum number of strips, such as... Figure 5 As shown.

[0074] Let the first one in the diagram The coordinates of the two endpoints of each strip are respectively and It can be obtained Each strip endpoint.

[0075] (10) (11) (12) (13) Based on the strip endpoints From the left of Gaussian coordinates, return to latitude and longitude, then transform to the Earth-centered Earth-fixed coordinate system, denoted as... and Geostationary satellites have no relative motion with the Earth, and their orbits... Since this information is known, the position vector in the Earth-centered Earth-fixed system is used. With velocity vector The required satellite attitude for each strip endpoint is calculated using a 321 rotation sequence, with the payload pointing to that endpoint.

[0076] , , (14) (15) (16) (17) (18) in, , , These are the coordinate axes of the satellite orbital system. This is the transformation matrix from the Earth-centered Earth-solid system to the orbital system. The satellite body in the orbital system points to the end of the strip. The vector. This refers to the satellite's elevation angle. This refers to the roll angle of the satellite itself. This is the symbol extraction function. Similarly, the satellite's orientation can be determined. Required pitch angle With roll angle .

[0077] (3) Solving for satellite mission parameters The geostationary satellite body needs to be pointed sequentially to each end of each strip, while the payload must remain powered on during attitude transitions. Calculations are performed separately. With the two edge strip endpoints ( , , , The satellite uses the geocentric angle of the finite angle as the starting point for observation and adopts an "S"-shaped folding backscan strategy to reduce the overall maneuverability of the satellite.

[0078] by Taking the starting point as an example, let the time when the star cluster receives the user's regional search request be _____. This describes the satellite mission execution process, such as... Figure 6 As shown. The mission begins at any moment. The satellite body begins to maneuver from zero attitude. Pitch angle reached at any moment The roll angle reached The line of sight of the body load Load start-up, i.e. Subsequently, the satellite continued maneuvering along the current strip, with its line of sight at... Time reaches the other end Then, the satellite continued its maneuvering, with its line of sight at... The time reaches the endpoint of the adjacent and unobserved strip. ,At Time reaches the endpoint Repeat this iteration until... At that moment, the line of sight points to the endpoint. ( (even number) or endpoints ( (If the number is odd), the region is completely covered, and the load is shut down. Subsequently, the satellite itself was... The task ends when the target is returned to a zero-position state. The result can be obtained from the satellite's angular velocity and attitude. to This allows us to obtain the parameters for the geostationary satellite mission.

[0079] (19) (20) (twenty one) (twenty two) In the formula, The modulo function is used. During task execution, the pose at any given time can be obtained by approximating the imaging poses of two adjacent strip endpoints using a first-order linear fit.

[0080] Target tracking strategy for geostationary satellite turntable payloads based on neighborhood transfer After the geostationary satellite's payload detects a target, it outputs the target's position. The turntable payload then continuously tracks the target through turntable maneuvers. Since the target's position may change in real time, if the turntable payload maintains its line of sight pointing towards the target, the turntable must constantly perform attitude maneuvers, which is extremely inconvenient for precise turntable control and energy-efficient utilization. To address this, a neighborhood transfer strategy is adopted. This method does not require constant adjustment of the turntable attitude; it only corrects the turntable attitude when the target is about to move to the edge of the field of view, ensuring that the target remains within the turntable payload's field of view and achieving target tracking.

[0081] The moment when the target is first captured by the payload after the area search mission is completed. ,Location With speed This can be considered as known information. The captured latitude and longitude are converted into vectors in the geocentric Earth-fixed coordinate system. Turntable at Always start maneuvering from zero attitude. The turntable load line of sight is at... Always pointing to the capture position, the payload is powered on. At this point, the turntable pitch angle is set to... Roll angle set to When calculating the turntable's observation attitude, the attitude coupling between the turntable and the satellite body must be considered. The satellite body's attitude at any given time has already been determined, and its pitch angle is denoted as... The roll angle is denoted as Then we have: (twenty three) (twenty four) In the formula, The transformation matrix from the orbital system to the home system is given. This is the vector pointing from the turntable load to the capture position in this system. Substituting into equations (17) and (18), we can similarly obtain the answer. and The load start-up time can then be determined based on the turntable's angular velocity.

[0082] (25) The projection of the turntable load onto the equator is a perfect circle, and its diameter is the width. By maneuvering the turntable to make the two imaging fields tangent, the maximum neighborhood transfer time can be calculated. .

[0083] (26) (27) (28) (29) In the formula, For the Earth's radius, For half-amplitude load geocentric angle, The load field of view is half the angle of the field of view. The distance from the turntable load to the edge of the projection is denoted as . The total time for the payload to receive, calculate, and process data, such as Figure 7 As shown.

[0084] Then, based on the target's historical maximum speed, the maximum distance the target can move when the turntable load is transferred to the neighboring area can be calculated. .

[0085] (30) Convert the target acquisition location from latitude and longitude to Gaussian coordinates, denoted as . Using this location as the geometric center, construct a circle with a side length of... The hexagonal shape within the safe zone is called the safe zone. When the target is within the safe zone, the turntable does not need to perform attitude maneuvers.

[0086] (31) Next, six adjacent neighborhoods of the same size as the safe zone are generated, with their center points having Gaussian coordinates as follows: and ,like Figure 8 As shown.

[0087] When a time-sensitive target moves out of the safe range, it is still within the turntable's payload field of view. Therefore, the geostationary satellite can directly determine which adjacent neighborhood the target has entered. Subsequently, the center point of that neighborhood is used as the turntable's payload line of sight pointing point, and the turntable performs attitude maneuvers. The center point is converted from Gaussian coordinates back to latitude and longitude, and substituted into equations (23), (24), (17), and (18). Similarly, the attitude of the turntable at any moment during the transfer to the neighborhood is obtained.

[0088] In the most extreme case during target tracking, the turntable begins to shift to a neighboring area the instant the target touches the edge of the safe zone, and the target immediately and drastically changes its direction of movement. For example... Figure 9 As shown, the target is in A The point was captured, and then... B Point movement, B The point is the intersection of three safety zones. When the target is within... B At that moment, the turntable detected that the target had reached the edge of the current safe range, and the load began to move along... AD The direction shifts towards the neighboring area. The target then changes direction along... BC Continue moving in the direction. By setting the side length of the safety range as... This ensures that the distance from any point on the edge of the safe zone to the edge of the adjacent field of view is always greater than or equal to the distance from the edge of the adjacent field of view. Therefore, once the turntable attitude switch is complete, the load center reaches... D The target was reached precisely at that point. C At this point, the turntable's payload field of view can still cover the target, completing the target localization.

[0089] Subsequently, using the new turntable load pointing point as the center, a safe range and neighborhood are constructed. Continuous iteration using the aforementioned method enables continuous tracking and acquisition of the time-sensitive target. Since the time-sensitive target is non-cooperative, observation failures may occur, leading to target loss. At this point, the turntable returns to its zero attitude, and the target tracking task ends. The main payload then performs a new region search to locate the target.

[0090] Accessibility-based low-Earth orbit constellation identification and confirmation strategy Due to the long distance and low resolution of geostationary orbit satellites, they can only output location information for time-sensitive targets. Therefore, low-Earth orbit (LEO) satellite constellations are needed for detailed observation of time-sensitive targets to confirm whether the targets are worth continuous observation. Time-sensitive targets have high time sensitivity; however, the access window of LEO satellites has a significant lag. After a geostationary orbit satellite acquires a target, it transmits the location information to an LEO satellite. The LEO satellite may pass by the target after a period of time, by which time the target may have already left its previous acquisition location.

[0091] In response, once the target is captured, any low-orbit satellite Determine an orbital period based on its own orbit. Within this range, is there an access window for the target's potential range? The target's potential range is a circular region, with its center being the target's final capture location and its radius being the maximum distance the time-sensitive target can travel within one orbital period of the current satellite. The low-Earth orbit satellite orbit is known information, let... The semi-major axis is Then we have: (32) (33) In the formula, The gravitational constant is the constant of gravity. The target is the highest historical capture speed.

[0092] Divide the potential area into several points at equal intervals, and let the position vector of any point within the potential area in the Earth-centered Earth-solid system be . At a certain moment, low-orbit satellites The position vector in the Earth-centered Earth-fixed system is: The maximum maneuver angle is .like Located on the same side of the Earth as this point, and pointing towards... vector and The included angle is not greater than ,but Accessibility to this point, such as Figure 10 As shown, the accessibility condition is: (34) At the current moment, if a satellite has accessibility to any point within the potential range, it is considered to have accessibility to the potential range. Subsequently, the satellite orbits are traversed over time, calculating the satellite's accessibility to the potential range per second. If at a certain moment a satellite has accessibility to the potential range, but not in the preceding second, then that moment is the start of the access window. If at a certain moment a satellite has accessibility to the potential range, but not in the following second, then that moment is the end of the access window. This allows us to determine all satellites within the constellation that have accessibility to the target potential range, as well as the access windows themselves. Using these satellites as resources for identification and confirmation mission planning effectively avoids wasting computational resources caused by satellites lacking observation capabilities.

[0093] After accessibility screening, the set of access windows for low-Earth orbit constellations to the potential target region can be obtained, denoted as . .in, This indicates the number of low-orbit constellations relative to the target's current position. One access window, The sequence number of the satellite to be accessed. At the start time of accessing the window, This is the time when the access window ends.

[0094] Once a satellite is determined to have an access window within the potential range of a target, it enters a mission waiting state. This is to ensure the satellite can achieve vertical overhead observations of the target as much as possible. At that moment, the low-Earth orbit satellite re-requests the latest target acquisition position from the geostationary orbit satellite, and then calculates and updates the access window for the acquisition position. and .

[0095] Satellites can to Observations can be performed at any time interval. However, the satellite requires different attitudes to observe the same location at different times, leading to differences in image resolution, radiometrics, and geometric quality. During target observation, the smaller the satellite's maneuver angle, the higher the image quality. Within an access window, the distance between the satellite's nadir and the target reaches its minimum at the instant the satellite makes a vertical overhead pass. Since the access window for low-Earth orbit satellites to ground targets is short, the effects of Earth's rotation and target movement can be ignored; therefore, the moment the satellite makes an overhead pass is approximately considered the midpoint of the access window. , .like Figure 11 As shown, in At any time, the satellite can point the payload's line of sight to the target without performing pitch maneuvers.

[0096] This is the midpoint of the access window, which is also the midpoint of the payload's startup time. To ensure sufficient observation of the target by the low-Earth orbit satellite, the entire visible window should be used to image the time-sensitive target, but the imaging time must not exceed the maximum startup duration per session. From this, the payload's startup time can be calculated. With the time of shutdown .

[0097] , (35) Low-orbit satellites Substituting the position vector at time and the target acquisition position vector into equations (14) to (18), the satellite's position can be obtained. The imaging attitude of the target at all times is recorded as the pitch angle. The roll angle is denoted as Then, based on the satellite's maneuver angular velocity... The start time of the task can then be determined. .

[0098] (36) Similarly, we can calculate the satellite's position. Moment of maneuver angle and mission end time This ultimately yields a set of low-Earth orbit satellite missions that have access windows to the potential target range within the current satellite orbital period.

[0099] Heterogeneous constellation collaborative applications rely on interaction and negotiation between satellites, requiring real-time adjustments to constellation mission plans based on observation results to adapt to complex and ever-changing application scenarios. To address this, this invention proposes employing a contract network algorithm to plan the search, tracking, and identification missions of geostationary satellites and low-Earth orbit constellations for non-cooperative time-sensitive targets.

[0100] The heterogeneous constellation includes one geostationary satellite. Because the relative position of the geostationary satellite to the ground station is fixed and it has broad coverage of the low-Earth orbit constellation, the geostationary satellite was selected to receive ground requests and disseminate mission information within the contract network. The mission planning process for the heterogeneous constellation based on the contract network is as follows: Figure 12 As shown.

[0101] Step 1: The geostationary satellite acts as the evaluator, receiving observation requests from ground users for the suspected area.

[0102] Step 2: The geostationary satellite payload generates a region search task based on a folded backscan strategy. After the search is completed, the task execution results are sent to ground users. If no time-sensitive targets are found, this round of the task ends. If time-sensitive targets are found, proceed to the next step.

[0103] Step 3: The geostationary satellite turntable payload generates a non-cooperative time-sensitive target tracking task based on a neighborhood transfer strategy. During the tracking process, the task execution results are sent to the ground user.

[0104] Step 4: The geostationary satellite locates the time-sensitive target. When a low-Earth orbit (LEO) satellite enters the geostationary satellite's coverage area, the geostationary satellite generates a tender document and issues it to the LEO satellite, completing the contract network bidding process. The tender content is based on the constellation mission planning model and can be represented as the geostationary satellite's most recent acquisition information of the time-sensitive target. ,in Indicates the moment of capture. Indicates the latitude of the capture point. Indicates the longitude of the capture point. Indicates the capture point height. The capture point velocity.

[0105] Step 5: The low-Earth orbit (LEO) satellite constellation receives tender documents, generates identification and confirmation tasks based on accessibility screening strategies, submits mission proposals to geostationary orbit satellites, and completes the online contract bidding process. The tender content can be represented as follows: ,in To execute the satellite serial number, This refers to the moment the load is shut down. This refers to the satellite's attitude.

[0106] Step 6: After receiving all mission plans from low-Earth orbit satellites within its coverage area, or after the submission deadline, the geostationary satellite evaluates the plans. Earlier mission execution plans have a higher probability of capturing non-cooperative time-sensitive targets, and smaller maneuver angles correspond to lower energy consumption costs. Therefore, the geostationary satellite evaluation needs to comprehensively consider timeliness and maneuver costs, and normalize the payload shutdown time and satellite attitude for this mission round. The assessment results are expressed as Then we have: (37) in, This is the latest payload shutdown time submitted for this round of low-Earth orbit satellites. This is the earliest time to shut down. This represents the maximum attitude value of the low-Earth orbit satellite during this mission. This represents the minimum pose value. This is the timeliness coefficient. This represents the mobility cost coefficient.

[0107] Step 7: The geostationary satellite will sort the scores of the mission proposals in this round from highest to lowest, select the satellite belonging to the mission proposal with the highest score as the execution satellite, and announce the contract network bidding results.

[0108] Step 8: The winning low-orbit satellite performs the task of identifying and confirming time-sensitive targets and feeds back the observation results to ground users.

[0109] Since time-sensitive target tracking is a continuous task, the Contract Network algorithm will repeatedly execute steps 4 to 8 whenever a low-Earth orbit satellite enters the coverage area of ​​a geostationary orbit satellite to achieve continuous tracking and confirmation of the target. Simultaneously, considering the uncertainty of time-sensitive targets, whenever a time-sensitive target is lost, the Contract Network algorithm will re-execute steps 2 to 8 to attempt to retrieve the lost target.

[0110] Simulation Analysis Scene setting The simulation uses UTC time. The scenario starts at 00:00:00 on 2026 / 01 / 01 and ends at 00:00:00 on 2026 / 01 / 02.

[0111] The geostationary satellite has a nadir longitude of 150° and a latitude of 0°, carrying two infrared payloads. The low-Earth orbit (LEO) constellation adopts a Walker configuration, distributed across 25 orbital planes, with 15 satellites evenly distributed in each plane. The constellation phase factor is 1, totaling 375 LEO satellites, each carrying one infrared payload. Detailed parameters of the geostationary satellites and the reference LEO satellite are shown in Table 1. The orbital elements in the table are, in order, semi-major axis (km), eccentricity, orbital inclination (°), right ascension of the ascending node (°), argument of perigee (°), and mean anomaly (°). The LEO satellite names include the orbital plane number and the in-plane number, respectively.

[0112] Table 1 Satellite Parameters

[0113] The area to be observed is a large sea area located on the western side of the Pacific Ocean, and its detailed geographical parameters are shown in Table 2.

[0114] Table 2 Regional Parameters

[0115] The non-cooperative time-sensitive target is a surface ship with a speed of 20 m / s. Its starting point is within the observation area, and its journey begins at 00:00:00 and ends at 22:19:23. Throughout the entire movement, the time-sensitive target generally moves northward, but frequently modulates its direction of motion. The area location and the time-sensitive target's path are shown below. Figure 13 As shown in the figure, the purple polygon represents the region, and the yellow curve represents the time-sensitive target.

[0116] Algorithm verification Collaborative observation mission planning is conducted using geostationary satellites and low-Earth orbit constellations to observe regional and non-cooperative time-sensitive targets. Initially, regional geographic information is a known condition for mission planning and is directly selected by the user. Time-sensitive targets are unknown conditions; their motion states must be acquired through satellite observation missions. (Timeliness coefficient) Motor cost coefficient To simulate real-world application scenarios, a 2% probability of imaging failure is set for each observation mission performed by the satellite. If an imaging failure occurs, the time-sensitive target will be lost.

[0117] As planned, the GEO satellite's payload will first employ a folding backflash strategy to plan and execute the regional search mission. The mission maneuver will begin at 00:00:00, imaging will begin at 00:02:30, imaging will end at 00:15:14, and the maneuver will end at 00:19:15. The satellite's attitude and imaging timeframe are as follows: Figure 14 As shown. During the mission, the GEO satellite's maneuver angle and angular velocity both met the constraints, thus the satellite's payload area search mission was feasible.

[0118] The GEO satellite body maneuvers according to the above attitude planning results, and the payload is activated according to the imaging window. The payload pointing path and area coverage are as follows. Figure 15 As shown in the figure, the dark blue broken line represents the changing path of the load's projection on the ground, and the green area represents the overall coverage area during the load's operation period. This demonstrates that the load achieves complete coverage of the area.

[0119] During the imaging period, the GEO satellite payload detected a time-sensitive target at 00:06:53, thus obtaining the target's initial position and velocity information. Subsequently, the GEO satellite turntable payload planned and executed a time-sensitive target tracking mission based on a neighborhood transfer strategy. Simultaneously, the low-Earth orbit (LEO) constellation, based on the real-time position of the time-sensitive target captured by the tracking mission, planned and executed an identification and confirmation mission based on an accessibility screening strategy.

[0120] As planned, the turntable payload began tracking the time-sensitive target at 00:19:15. During the tracking task, at 12:00:19, the time-sensitive target was lost due to the imaging failure probability, and continuous tracking was interrupted, restoring the initial attitude. The main payload planned and executed a region search task based on the loss location and time, and the coverage of the potential range of the initial loss location was as follows: Figure 16As shown in the figure, the red dots represent the lost locations of the time-sensitive target, the red semi-transparent circles represent the potential range of the target, and the yellow dots represent the actual locations of the time-sensitive target. The main payload recovered the lost time-sensitive target at 12:09:55, and the turntable payload subsequently resumed continuous tracking of the time-sensitive target at 12:18:52.

[0121] The time-sensitive target's journey ended at 22:19:23, therefore, the time-sensitive target was lost again, and the turntable load's continuous tracking was interrupted again. The main load also performed an area search task, and the coverage of the potential range of the second lost location is as follows. Figure 17 As shown. No time-sensitive targets were found in this search, and the GEO satellite mission has ended.

[0122] The GEO satellite turntable payload performed 44 time-sensitive target tracking missions, completing two rounds of continuous tracking. The attitude and imaging time periods of the turntable payload tracking missions are as follows: Figure 18 As shown in the figure. During the mission, the turntable load's maneuver angle and angular velocity both satisfy the constraints, therefore the turntable load target tracking mission is feasible.

[0123] The path of the turntable load pointing point is as follows Figure 19 and Figure 20 As shown in the figure, the bright blue line represents the path of the turntable load pointing to the point. The coverage of the time-sensitive target by the turntable load is as follows. Figure 21 As shown in the figure, the red area represents the overall coverage of the time-sensitive target during the turntable payload's operation. During the tracking process, although the time-sensitive target was lost between 12:00:19 and 12:18:52, it was successfully retrieved using the main payload through GEO satellite payload collaborative planning. Furthermore, by using two consecutive tracking operations with the turntable payload, full coverage of the time-sensitive target was achieved during the non-lost period.

[0124] Because the turntable payload can continuously provide motion information of time-sensitive targets to the LEO constellation during the tracking mission, LEO satellites need to observe the time-sensitive targets if they have an access window to the potential range of the targets. As planned, the LEO constellation will perform a total of 160 identification and confirmation missions. Among them, the mission attitude and imaging period of LEO-6-3 satellite between 00:29:00 and 00:33:00 are as follows: Figure 22 As shown, during the observation process, the low-orbit satellite's maneuver angle, angular velocity, and power-on duration all met the constraints, thus the low-orbit satellite identification and confirmation mission is feasible.

[0125] For example, the observation scenarios of time-sensitive targets in a single identification and confirmation mission by the LEO-6-3 satellite are as follows. Figure 23As shown in the figure, the white curve represents the satellite orbit, the white dots represent the satellite positions, the yellow dots represent the time-sensitive target positions, and the semi-transparent dark blue cone represents the payload's field of view. The low-Earth orbit (LEO) satellites effectively cover the actual positions of the time-sensitive targets based on their potential locations. The 160 coverage operations of the time-sensitive targets by the LEO constellation are shown below. Figure 24 As shown, the dark blue area in the figure is formed by superimposing the single coverage areas of all low-Earth orbit satellites, ultimately presenting a strip shape. Due to the loss of time-sensitive targets, the low-Earth orbit satellite constellation could not obtain the location information of time-sensitive targets during this period, resulting in the time-sensitive target's path not being covered during this time period. However, it achieved full coverage of the time-sensitive target's entire path during the non-loss period.

[0126] In total, the GEO satellites and the low-Earth orbit (LEO) constellation performed 207 missions. The GEO satellite payload itself performed three regional search missions, achieving initial localization and recovery of lost time-sensitive targets. The GEO satellite turntable payload performed 44 target tracking missions, achieving temporal coverage of time-sensitive targets during non-lost periods. The LEO constellation performed 160 identification and confirmation missions, achieving high-frequency observation of time-sensitive targets during non-lost periods.

[0127] Algorithm Comparison Based on the set scenario, without considering imaging failure, the region search and target tracking task planning method of the present invention (Method 1), the target tracking task planning method of region search and nine-square grid neighborhood transfer along the latitude and longitude direction

[21] (Method 2), and the region search and target tracking task planning method using only low-orbit star clusters (Method 3) were compared and analyzed.

[0128] As planned, both Method 1 and Method 2 achieved complete coverage of the region using GEO satellite payloads. The changes in the payload pointing path are as follows: Figure 25 As shown. Method 3 used a low-Earth orbit constellation to perform 33 strip pushbroom missions, achieving complete coverage of the region, as shown in the figure. Figure 26 As shown in the table. The key performance of the three methods is shown in Table 3, with the optimal values ​​highlighted in bold.

[0129] Table 3 Key performance parameters for the region search task

[0130] Method 1 uses a rotating caliper algorithm to find the minimum bounding rectangle of the region, thereby achieving a significant reduction in the number of attitude transitions and an effective reduction in the path length of the pointing point with the fewest possible strips. Compared to Method 2, this advantage directly translates into a significant reduction in the time taken for the region search task, demonstrating higher execution efficiency. Since Method 2 always searches along latitude and longitude, GEO satellites can use single-axis rotation, while Method 1's search direction is not fixed, requiring GEO satellites to use dual-axis rotation. Therefore, the total attitude maneuver of Method 1 is greater than that of Method 2, although the difference is not significant. Method 3 only uses low-Earth orbit (LEO) satellites for the region search. However, LEO satellites have a small payload swath and a short observation window, requiring the use of observation strips from multiple satellites for splicing coverage. This results in Method 3 having a significantly higher number of attitude transitions, a larger total attitude maneuver, a longer pointing point path, and a longer task time than Method 1 and Method 2. When the LEO constellation completely covers the region, the time-sensitive target has already moved out of the original region, making it impossible to capture. Therefore, the method of the present invention can significantly shorten the time required for regional search tasks while ensuring complete regional coverage, and discover time-sensitive targets in the region earlier.

[0131] The path changes of the turntable load pointing point during the target tracking task are as follows: Method 1 and Method 2 Figure 27 As shown in the table. The key performance indicators of the two methods are shown in Table 4, with the better values ​​highlighted in bold.

[0132] Table 4 Key performance parameters of GEO satellite turntable payload target tracking mission

[0133] Both Method 1 and Method 2 successfully planned the continuous tracking task for time-sensitive targets. Method 1 had fewer turntable payload attitude transitions, less total attitude maneuvering, and shorter pointing point path than Method 2. Due to the fewer attitude transitions in Method 1, the pointing point path in Method 1 deviated further from the actual path of the time-sensitive target compared to Method 2, but it still kept the time-sensitive target within the turntable payload's field of view. Method 3 relies on low-Earth orbit (LEO) satellite observations, but the observation time window is extremely fixed and limited, making it difficult for LEO satellites to obtain continuous position information of the time-sensitive target. Especially in this scenario, the time-sensitive target frequently changes its direction of motion, making it impossible for Method 3 to effectively track the time-sensitive target. Therefore, the method of this invention can effectively reduce the number of attitude maneuvers of the GEO satellite turntable payload while minimizing the loss of the time-sensitive target, thereby fully utilizing the advantages of the GEO satellite's field of view and improving the field of view utilization rate.

[0134] The above algorithm verification and comparison show that the heterogeneous constellation dynamic cooperative mission planning method proposed in this invention can achieve rapid regional search and continuous tracking of time-sensitive targets by geostationary satellites with high attitude maneuver efficiency, realize fine observation of time-sensitive targets by low-orbit constellations, and have the ability to handle emergency situations where time-sensitive targets are lost.

[0135] Implementation Method 2 This embodiment provides a heterogeneous constellation cooperative search and tracking mission planning system equipped with a turntable payload. The planning system uses the heterogeneous constellation cooperative search and tracking mission planning method equipped with a turntable payload as described in Embodiment 1. The planning system includes... Demand response and area search module: The geostationary satellite, acting as the evaluator, receives ground requests and searches for suspicious areas based on the folded backscan strategy. If no target is found, the search ends; if a target is found, the search begins. Target positioning and mission bidding module: The geostationary satellite locks onto the time-sensitive target and calculates the trajectory. When the low-orbit satellite enters the field of view, it generates a bid based on the latest acquisition information and issues the observation bid to the low-orbit satellite cluster. Scheme evaluation and awarding module: Low-Earth orbit satellites generate identification schemes based on accessibility screening and submit bids; Geostationary orbit satellites comprehensively evaluate all schemes, select the best satellite and announce the results; Mission execution and closed-loop module: The winning low-orbit satellite performs target identification and confirmation tasks and directly feeds back the detailed investigation results to the ground user, thus completing the closed loop.

Claims

1. A method for planning heterogeneous constellation cooperative search and tracking missions equipped with a turntable payload, characterized in that, The planning method includes the following steps: Step 1: The geostationary satellite, acting as the evaluator, receives ground requests and searches for suspicious areas based on a folded backscan strategy. If no target is found, the search ends; if a target is found, the search begins. Step 2: The geostationary satellite locks onto the time-sensitive target and calculates its trajectory. When the low-orbit satellite enters the field of view, a tender document is prepared based on the latest acquisition information, and an observation tender is issued to the low-orbit satellite constellation. Step 3: Low-Earth orbit (LEO) satellites generate identification schemes based on accessibility screening and submit bids; geostationary orbit (GEO) satellites comprehensively evaluate the various schemes, select the best winning satellite, and announce the results. Step 4: The winning low-orbit satellite performs target identification and confirmation tasks and directly feeds back the detailed investigation results to the ground user, completing the closed loop.

2. The planning method according to claim 1, characterized in that, Step 1 specifically includes the following steps: Step 1.1: The geostationary satellite, acting as the assessor, receives observation requests from ground users for the suspected area; Step 1.2: The geostationary satellite payload generates a region search task based on the folding back scan strategy; after the search is completed, the task execution results are sent to the ground user; if no time-sensitive target is found, the current round of the task ends; if a time-sensitive target is found, proceed to the next step. Step 1.3: The geostationary satellite turntable payload generates a non-cooperative time-sensitive target tracking task based on a neighborhood transfer strategy; during the tracking process, the task execution results are sent to the ground user.

3. The planning method according to claim 2, characterized in that, Specifically, step 1.2 involves solving for the payload coverage area when using the geostationary satellite's payload to search a large area, determining that the payload swath width is smaller than the area width. Therefore, the geostationary satellite needs to perform repeated scanning of the area through attitude maneuvers, forming multiple strips on the ground. Only after these strips are stitched together can the complete coverage of the area be achieved. To this end, the payload coverage area is first solved based on the regional geographic information, and then the key attitudes of the satellite during the mission are calculated based on the scanning method, ultimately obtaining the geostationary satellite mission parameters.

4. The planning method according to claim 2, characterized in that, Specifically, step 1.3 involves the geostationary satellite payload detecting a target and outputting the target's position. The turntable payload then continuously tracks the target via turntable maneuvers. Since the target's position may change in real time, a neighborhood transfer strategy is adopted, correcting the turntable attitude only when the target is about to move to the edge of the field of view, ensuring that the target remains within the turntable payload's field of view and thus achieving target tracking. The moment when the target is first captured by the payload after the area search mission is completed. ,Location With speed This can be considered as known information; the captured latitude and longitude coordinates are converted into vectors in the geocentric Earth-fixed coordinate system. Turntable at The maneuver begins from zero attitude; the turntable load line of sight is at... The payload is powered on and constantly pointed to the capture position. The projection of the turntable load onto the equator is a perfect circle. When the turntable maneuvers to make the two imaging fields tangent, the maximum neighborhood transfer time can be calculated. Then, based on the target's historical maximum velocity, the maximum target movement distance during the turntable load's neighborhood transfer can be determined. The target acquisition position is converted from latitude and longitude to Gaussian coordinates, and a circle with a side length of [missing information] is constructed with this position as the geometric center. The regular hexagon is called the safe zone. When the time-sensitive target moves out of the safe zone, the target is still within the turntable's payload field of view. Therefore, the geostationary satellite can directly determine which adjacent neighborhood the target has entered. Then, the center point of that neighborhood is used as the turntable's payload line of sight pointing point, and the turntable performs attitude maneuvers. During target tracking, the most extreme case is when the target touches the edge of the safe zone, the turntable begins to move to the neighborhood, and the target immediately changes its direction of movement drastically. Subsequently, the safe zone and neighborhood are constructed again with the new turntable load pointing point as the center. By continuously iterating according to the above method, the continuous tracking and acquisition of time-sensitive targets can be achieved. Since time-sensitive targets are non-cooperative targets, there may be cases where observation failures lead to target loss. At this point, the turntable returns to its zero attitude, and the target tracking mission ends; The payload then performs a new area search to locate the target.

5. The planning method according to claim 1, characterized in that, Step 2 specifically involves the geostationary satellite locating the time-sensitive target. When a low-orbit satellite enters the geostationary satellite's coverage area, the geostationary satellite generates a tender document and issues it to the low-orbit satellite, completing the contract network bidding process. The tender content is based on the constellation mission planning model and can be represented as the geostationary satellite's most recent acquisition information of the time-sensitive target.

6. The planning method according to claim 5, characterized in that, The constellation mission planning model is specifically a constellation mission planning model whose inputs include geostationary orbit satellite parameters, low orbit satellite parameters, and regional geographic parameters. The model variable is the actual trajectory of the time-sensitive target; The constellation mission planning algorithm needs to achieve efficient collaborative observation of targets by the constellation; ultimately, the model output includes a set of constellation missions and time-sensitive target acquisition tracks.

7. The planning method according to claim 1, characterized in that, Step 3 specifically includes the following steps: Step 3.1: The low-Earth orbit satellite constellation receives tender documents, generates identification and confirmation tasks based on the accessibility screening strategy, submits the task plan to the geostationary orbit satellite, and completes the online bidding for the contract; Step 3.2: After receiving all mission proposals from low-Earth orbit satellites within its coverage area or after the proposal submission deadline, the geostationary satellite evaluates the proposals. Step 3.3: The geostationary satellite will sort the scores of the mission proposals in this round from highest to lowest, select the satellite belonging to the mission proposal with the highest score as the execution satellite, and announce the contract network bidding results.

8. The planning method according to claim 7, characterized in that, Step 3.1 specifically involves using a low-Earth orbit (LEO) satellite constellation to conduct detailed observations of the time-sensitive target to confirm whether the target is worth continuous observation. Time-sensitive targets have high timeliness, but the LEO satellite access window has a significant lag. After a geostationary satellite acquires the target, it sends its positioning information to the LEO satellite. After a period of time, the LEO satellite passes the target, and the target may have already left its previous acquisition position. Therefore, after the target is acquired, any LEO satellite determines, based on its own orbit, whether there is an access window for the target's potential range within one orbital period. The potential range of the target is a circular area, with its center being the target's final acquisition position and its radius being the maximum movement distance of the time-sensitive target within one orbital period of the current satellite. Divide the potential area into several points at equal intervals, and let the position vector of any point within the potential area in the Earth-centered Earth-solid system be . At a certain moment, low-orbit satellites The position vector in the Earth-centered Earth-fixed system is: The maximum maneuver angle is ;like Located on the same side of the Earth as this point, and pointing towards... vector and The included angle is not greater than ,but The satellite is considered to have access to the potential range if it has access to any point within the potential range at the current moment. Then, the satellite orbit is traversed over time to calculate the satellite's accessibility to the potential range per second. If at a certain moment the satellite has access to the potential range but not in the previous second, then that moment is the start of the access window. If at a certain moment the satellite has access to the potential range but not in the next second, then that moment is the end of the access window.

9. The planning method according to claim 1, characterized in that, Specifically, step 4 involves the winning low-orbit satellite performing the task of identifying and confirming time-sensitive targets and feeding back the observation results to ground users.

10. A heterogeneous constellation cooperative search and tracking mission planning system equipped with a turntable payload, characterized in that, The planning system uses a heterogeneous constellation cooperative search and tracking mission planning method with a turntable payload as described in any one of claims 1-9, and the planning system includes... Demand response and area search module: The geostationary satellite, acting as the evaluator, receives ground requests and searches for suspicious areas based on the folded backscan strategy. If no target is found, the search ends; if a target is found, the search begins. Target positioning and mission bidding module: The geostationary satellite locks onto the time-sensitive target and calculates its trajectory. When the low-orbit satellite enters the field of view, it generates a bid based on the latest acquisition information and issues an observation bid to the low-orbit satellite constellation. Scheme Evaluation and Awarding Module: Low-Earth Orbit satellites generate identification schemes based on accessibility screening and submit bids; A comprehensive evaluation of all proposed solutions for geostationary satellites was conducted, and the winning satellite was selected and the results announced. Mission execution and closed-loop module: The winning low-orbit satellite performs target identification and confirmation tasks and directly feeds back the detailed investigation results to the ground user, thus completing the closed loop.

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