Method and device for planning target observation task of satellite group over-the-ground area

Abstract

The invention discloses a method and a device for planning a target observation task of a satellite group to the ground, and relates to the method and the device for planning the target observation task of the ground. The objective of the invention is to solve the problems of long operation time of the visibility of a satellite to a regional target and missing coverage of the regional target in an existing satellite group to regional target observation task planning algorithm. The planning method provided by the invention comprises the following steps: step 1, screening satellites for executing tasks; step 2, calculating a visible time window of the satellite to the regional target; calculating and screening out a circle set on the same side as the regional target based on the orbit circle decomposition of the satellite; judging whether the visible range is overlapped with the regional target according to the vertex of the visible range of the satellite at each moment, and calculating a visible time window; step 3, calculating an observation stripe expression of the regional target; and 4, a genetic algorithm task planning step. The invention belongs to the technical field of spaceflight.

Description

Technical Field

[0001] The present invention relates to a method and device for planning a ground area target observation mission, belonging to the field of aerospace technology. Background Art

[0002] Fields such as Earth science, environmental monitoring, and disaster warning require satellites to conduct intensive, timely, or periodic observations of specific areas on the Earth's surface. Due to the limitations of a single satellite platform, Earth observation coverage is limited, making coordinated observations by multiple satellites a primary approach in current satellite engineering. However, with the increasing number of satellites and the diversification of satellite payload types, mission planning and scheduling for constellations of multiple satellites often requires significant time. Urgent Earth observation missions require rapid mission planning and the most comprehensive target coverage possible. This requires improving the computational efficiency of satellite mission planning and refining the evaluation methods of the intelligent search algorithms used in mission planning.

[0003] Currently, the calculation of a satellite's visibility time window for regional targets is typically done by discretizing the regional target and treating it as a point target. This method, however, suffers from insufficient discretization density, resulting in reduced accuracy, while excessive density leads to high computational memory consumption. Existing regional target observations construct discrete strips of the region based on satellite de-satellite lines, with the strips separated by a fixed step size. This can lead to missing areas when combining different strips from different satellites during mission planning.

[0004] In summary, as the planning scenarios of satellite regional target observation missions become more complex, how to speed up the calculation speed of regional target mission planning and meet the requirements of regional target coverage is an urgent problem that needs to be solved. Summary of the Invention

[0005] The present invention aims to solve the problems of long satellite visibility calculation time for regional targets and omissions in regional target coverage in the existing satellite cluster regional target observation mission planning algorithm, and further proposes a satellite cluster regional target observation mission planning method and device.

[0006] The technical solution adopted by the present invention to solve the above-mentioned problem is as follows: the steps of the satellite constellation earth-area target observation mission planning method of the present invention include:

[0007] Step 1: Screening the satellites to perform the mission; screening the satellites to perform the mission based on the parameters of each satellite in the constellation and the target information;

[0008] Step 2: Calculate the satellite's visible time window for the regional target. Based on the decomposition of the satellite's orbital circles, calculate and filter out the circle set on the same side as the regional target. Based on the vertex of the satellite's visible range at each moment, determine whether the visible range overlaps with the regional target and calculate the visible time window.

[0009] Step 3: Calculate the observation strip expression of the regional target; calculate the satellite observation range according to the visible time window and the satellite position information, and select a specific observation strip within the observation range corresponding to the visible time window based on the strip selection parameter;

[0010] Step 4, genetic algorithm task planning step: Based on the chromosome encoding of multiple visible time windows of each satellite, an improved evaluation function is used to perform intelligent search for the satellite's observation time window selection and imaging attitude.

[0011] Furthermore, the process of selecting satellites to perform missions in step 1 is as follows:

[0012] Step 101: Determine the satellite payloads required to perform the observation mission based on the mission observation requirements provided by the user, remove satellite platforms that do not have the corresponding payloads from the constellation resources, and use the remaining satellites to form a satellite set capable of performing the mission.

[0013] Step 102: Determine the latitude and longitude position range of the regional target;

[0014] Step 103: Calculate the satellite observation range based on the satellite orbit data.

[0015] Furthermore, the step of determining the latitude and longitude position range of the regional target in step 102 includes:

[0016] Step 10201: Use multiple vertices to represent the area target. The vertices are arranged in a clockwise direction and are denoted as P = {p i |lat i ,lon i},1≤i≤n, where lat i Represents vertex p i Latitude, lon i Represents vertex p i The longitude of , n is the number of vertices;

[0017] Step 10202: Select the minimum and maximum latitude and longitude values in the vertex set, and record them as lat min ,lat max ,lon min ,lon max .

[0018] Furthermore, the step of calculating the satellite observation range based on the satellite orbit data in step 103 includes:

[0019] Step 10301: Read the orbital parameters and payload parameters of each satellite in the set of satellites that can execute the mission, and obtain the satellite's orbital inclination i, maximum roll maneuver angle β, and payload observation half-angle α.

[0020] Step 10302: Eliminate satellites that have no observation opportunities. Assuming the maximum observation range of a satellite is γ, where γ = α + β, then its maximum latitude coverage of the Earth is:

[0021] [-|i|-η,|i|+η],

[0022] in If the regional target is at a higher latitude, that is:

[0023]

[0024] There is no imaging opportunity for the satellite, and the visible window calculation is not performed. The satellite platform is directly deleted from the set of satellites that can execute the mission.

[0025] Furthermore, the process of calculating the satellite visibility time window for the regional target in step 2 is as follows:

[0026] Step 201: Set the start and end time of the regional target observation mission scene;

[0027] Step 202: Decomposing the orbits of mission-capable satellites; specifically, the following steps are performed:

[0028] Step 20201: Based on the set of satellites capable of executing the mission described in step 10302, obtain the orbital position data of each satellite during the time period from the beginning to the end of the scene; record the orbital data of each satellite as:

[0029]

[0030] Among them, Ps j represents the orbital position data set of satellite j during the time period from the beginning to the end of the scene, s is the total number of seconds from the beginning to the end of the scene, and t i represents the time of the i-th second, represents the position of the satellite in the ECEF coordinate system at the i-th second, represents the latitude and longitude of the satellite at the i-th second;

[0031] Step 20202: Divide the orbital position data of each satellite into circles; according to the satellite orbital data Ps obtained in step 20201 j , taking the highest and lowest points of the satellite orbit latitude as the boundary, the orbit data of each satellite in the scene time are grouped, that is, traversing Ps in order j In the data, for The situation is Then perform a interception and grouping, and finally get Ps j These data represent the position set of the satellite at each moment in the half circle after it passes the equator, which is recorded as the circle group of the satellite:

[0032] Ps j ={group1,group2,group3,group4,……} j ,

[0033] in, s k ≤i≤e k , s k 、e k are the start time and end time of the kth group respectively;

[0034] Step 203: Screen the satellite's circle groups;

[0035] Step 20301: Calculate the approximate midpoint position of the regional target (lat c ,lon c ),in Then set the height to 0 and convert to the ECEF coordinate system to obtain (x c ,y c ,z c );

[0036] Step 20302: Based on the satellite circle grouping obtained in step 20202, traverse each group of data in each satellite circle group {group 1, group 2, group 3, group 4, ...};

[0037] Step 20303: Get the approximate orbit data of each group of satellites. and An ECEF position data at the position, and the x, y, z coordinates of the two positions are obtained respectively;

[0038] Step 20304: Based on the coordinate positions in the x, y, and z directions in the two ECEF coordinate systems obtained in step 20303, calculate the angle between the position and the approximate midpoint position of the regional target.

[0039]

[0040] Step 20305: If both extracted coordinate positions have a condition of θ>90°, the half-circle track corresponding to the circle group is considered to be on the other side of the spherical surface where the regional target is located, and the group in the circle group is deleted. If a coordinate position has a condition of θ<90°, the half-circle track corresponding to the circle group is considered to be on the same side of the spherical surface where the regional target is located, and the group is not deleted.

[0041] Step 20306: After traversing the circle groups and performing the deletion operation, the circle group is the half-circle set on the same side of the satellite and the target;

[0042] Step 204: Calculate the visible time window of each satellite circle in each satellite circle group to the regional target;

[0043] Step 20401: The position of the satellite at the corresponding time can be known based on the satellite circle grouping obtained in step 203;

[0044] Step 20402: Get satellite position according to step 20401 ECEF position in Combining the satellite orbit height h, the maximum roll maneuver angle β observed by the satellite, and the payload observation half-angle α, the positions of the two vertices of the satellite observation range are calculated:

[0045] and

[0046]

[0047] Step 20403: Group each circle by satellite position The two vertex sets of the observation range corresponding to the calculated position at each moment are recorded as:

[0048]

[0049] Step 20404: Vertex collection ECEF coordinates converted to latitude and longitude

[0050] Step 20405, traverse group k view The two vertices corresponding to each moment in the , determine whether the vertex is located in the region target, that is, at least one vertex (lat, lon) corresponding to each moment satisfies:

[0051]

[0052] Among them, (lat i ,lon i )∈P and (lat n+1 ,lon n+1 )=(lat1,lon1),

[0053] Step 20406: Select group k view The moment when at least one vertex is located in the region target constitutes a set {vt i}, the visible time window of each lap is [st,et], where st=min{vt i}, et = max{vti}.

[0054] Furthermore, the process of calculating the observation strip expression of the regional target in step 3 is as follows:

[0055] Step 301: According to the visible time window of each satellite circle to the regional target, the visible time window of each satellite circle is integrated to obtain the access window set of the satellite to the regional target within the scene time, which is recorded as represents the set of visible time windows of satellite j to regional targets in the mission scenario;

[0056] Step 302: According to the satellite orbit position information Ps j , determine the orbital position of the satellite at the start and end time of each visible time window, and obtain the ECEF coordinate position {(x s ,y s ,z s ),(x e ,y e ,z e )} and longitude and latitude {(lat s ,lon s ),(lat e ,lon e )};

[0057] Step 303: Combine the ECEF coordinate position with the longitude and latitude to obtain the satellite's orbital altitude h at the start and end of each visible time window of the target observation;

[0058] Step 304: Calculate the swath vertex position based on the satellite's orbital altitude h and longitude and latitude positions at the start and end of each visible time window for target observation, combined with the maximum roll maneuver angle β observed by the satellite and the payload observation half-angle α.

[0059] Step 30401: Calculate the projections a and b of the payload half-angle observation half-width and the satellite roll maneuver half-width on the ground, where a = htanα, b = htan(α + β);

[0060] Step 30402: Consider the Earth as a sphere and calculate the change in the central angle corresponding to the half-width of satellite observation and the half-width of maneuvering side swing.

[0061]

[0062] Among them, R earth is the radius of the Earth;

[0063] Step 30403: Connect the two longitude and latitude positions of the satellite at the beginning and end of the visible time window to obtain a straight line

[0064] Step 30404: (lat s ,lon s ) and (lat e ,lon e ) Two points along a straight line The vertical translation distance a' is used to obtain the observation strip vertex in the visible time window when the satellite does not perform a lateral maneuver. The translation distance b' is used to obtain the vertex of the strip where the program opportunity exists within the visible time window of the satellite. The specific formula is as follows:

[0065]

[0066] Step 30405, set the strip selection parameter φ, φ∈[-1,1], and select the observation strip vertex as

[0067]

[0068] Furthermore, the process of the genetic algorithm task planning step in step 4 is called:

[0069] Step 401: Encode the chromosome; suppose there are N satellites in total, and the i-th satellite has W i visible time windows, each chromosome needs Gene bits, each gene bit can be a null value to indicate that the satellite does not perform observations in this time window, and φ∈[-1,1] to indicate that the satellite performs observations and is selected in the observation strips of the visible time window;

[0070] Step 402: randomly generate multiple chromosomes according to the encoding method of step 401 and initialize the population;

[0071] Step 403: Calculate the fitness of each individual in the population:

[0072] Step 40301: Calculate the observation coverage area based on the intersection of the rectangle formed by the observation strip vertices selected by each satellite in its visible time window and the area to be observed. Sum the coverage area of each window to obtain the observation coverage area of the mission planning scheme represented by the i-th individual. i ;

[0073] Step 40302: Calculate the overlapping area of multiple rectangles based on the rectangles formed by the observation strip vertices selected by each satellite in its visible time window, and sum up each overlapping area to obtain the observation overlapping area Overlap of the mission planning scheme represented by the i-th individual. i ;

[0074] Step 40303: Obtain the maneuvering attitude angle abs(φ)·β of each satellite in its visible time window according to the genetic coding number. Assuming that the energy consumed by satellite attitude conversion is proportional to the attitude conversion angle, the sum of the maneuvering attitude angles of each satellite in the visible time window is calculated. The energy consumption of the posture maneuver of the task planning scheme represented by the i-th individual can be obtained;

[0075] Step 40304: Calculate the fitness of the i-th individual. The fitness function is:

[0076]

[0077] Among them, Area P is the total area of the region to be observed, τ1, τ2, τ3 are constant coefficients with τ1>0, τ2<0, τ3<0, Φ is the function Φ(λ)=exp(λ);

[0078] Step 404: Select the individual with the highest fitness in the population and record it;

[0079] Step 405: Randomly select individuals for crossover and mutation:

[0080] Step 40501: Randomly select two individuals and randomly select a position, and exchange the genetic codes after the position between the two individuals;

[0081] Step 40502: Randomly select an individual, randomly select a position where the gene code is empty and add a random number [-1, 1];

[0082] Step 40503: Randomly select an individual, randomly select a position with a genetic code, and replace the number at that position with another random number in the range [-1, 1];

[0083] Step 406: Repeat the crossover and mutation operations and record the individual with the best fitness. After reaching the number of iterations, the individual with the best fitness is obtained.

[0084] Step 407: Decode the best fitness individual to obtain a task planning solution:

[0085] Step 40701: segment the gene according to the number of visible time windows of each satellite. The i-th segment corresponds to the visible time window of satellite i. The visible time window of satellite i has W i Then the gene segment has W i gene loci;

[0086] Step 40702: Each gene position containing a number is considered to be performing observation in the visible time window, and the roll maneuver angle during satellite observation is φ·β.

[0087] The present invention provides a constellation-to-earth regional target observation mission planning device, comprising a module for screening mission-performing satellites, a module for calculating a regional target visible time window, a module for calculating an observation band expression of a regional target, and a genetic algorithm mission planning module.

[0088] Screening module for satellites that can perform missions: preliminarily screen satellites that can perform missions;

[0089] Regional target visibility time window calculation module: This module decomposes the satellite's orbital circles, selects the circle set on the same side as the regional target, and then determines whether the visible range overlaps with the regional target to calculate the visibility time window;

[0090] Observation strip expression calculation module for regional targets: calculates the satellite observation range by calculating the visible time window and satellite position information, and constructs the observation strip expression based on strip selection parameters;

[0091] Genetic algorithm mission planning module: Chromosome encoding of multiple visible time windows of each satellite, and intelligent search of satellite observation time window selection and imaging posture.

[0092] The beneficial effects of the present invention are:

[0093] 1. The method and device for planning a constellation mission to observe a target in an Earth region according to the present invention screens the satellites to be executed and the sub-arcs of their orbits before calculating the visible time window for the target, thereby reducing the calculation range of the visible time window and improving the efficiency of the visibility calculation.

[0094] 2. The satellite constellation mission planning method and apparatus for observing regional targets on Earth, described in the present invention, determines visibility based on whether the satellite's observable range overlaps with the region, thus avoiding complex satellite-ground geometry calculations.

[0095] 3. The constellation mission planning method and apparatus for observing targets in the Earth region of the present invention uses strip selection parameters to indicate the selection of strips within the observable range, making strip selection continuous and avoiding omissions in strip splicing during mission planning due to strip interval selection.

[0096] 4. The method and apparatus for planning a constellation mission to observe regional targets on Earth, as described in the present invention, employs an improved fitness function method when optimizing an intelligent algorithm for mission planning using a genetic algorithm, thereby promoting complete observation coverage of regional targets.

[0097] 5. The method and device for planning a constellation's mission to observe ground targets described in the present invention are suitable for planning observation missions for a constellation composed of multiple satellites to observe ground targets. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Figure 1 This is a schematic diagram of the satellite's maximum latitude coverage;

[0099] Figure 2 It is a schematic diagram of the positions of the two vertices of the satellite observation range;

[0100] Figure 3 It is a schematic diagram of the satellite observation half-width and the maneuvering side swing half-width. DETAILED DESCRIPTION

[0101] Specific implementation method 1: Figures 1 to 3 As shown, a method for planning a constellation mission to observe a target in the Earth region includes the following specific steps:

[0102] Step 1: Screening the satellites to perform the mission; screening the satellites to perform the mission based on the parameters and target information of each satellite in the constellation; the specific process is as follows:

[0103] Step 101: Determine the satellite payloads required to perform the observation mission based on the mission observation requirements provided by the user, remove satellite platforms that do not have the corresponding payloads from the constellation resources, and use the remaining satellites to form a satellite set capable of performing the mission.

[0104] Step 102: Determine the latitude and longitude range of the regional target. The specific steps include:

[0105] Step 10201: Use multiple vertices to represent the area target. The vertices are arranged in a clockwise direction and are denoted as P = {p i |lat i ,lon i},1≤i≤n, where lat i Represents vertex p i Latitude, lon i Represents vertex p i The longitude of , n is the number of vertices;

[0106] Step 10202: Select the minimum and maximum latitude and longitude values in the vertex set, and record them as lat min ,lat max ,lon min ,lon max ;

[0107] Step 103: Calculate the satellite observation range based on the satellite orbit data. The specific steps include:

[0108] Step 10301: Read the orbital parameters and payload parameters of each satellite in the set of satellites that can execute the mission, and obtain the satellite's orbital inclination i, maximum roll maneuver angle β, and payload observation half-angle α.

[0109] Step 10302: Eliminate satellites that have no observation opportunity. Assume that the maximum observation range of a satellite is γ, where γ = α + β. Then, its maximum latitude coverage of the Earth is:

[0110] [-|i|-η,|i|+η],

[0111] in If the regional target is at a higher latitude, that is:

[0112]

[0113] If there is no imaging opportunity for the satellite, the visible window calculation is not performed and the satellite platform is directly deleted from the set of satellites that can perform the mission;

[0114] Step 2: Calculate the satellite visibility time window for regional targets. The specific process is as follows:

[0115] Step 201: Set the start and end time of the regional target observation mission scene;

[0116] Step 202: Decomposing the orbits of mission-capable satellites; specifically, the following steps are performed:

[0117] Step 20201: Based on the set of satellites capable of executing the mission described in step 10302, obtain the orbital position data of each satellite during the time period from the beginning to the end of the scene; record the orbital data of each satellite as:

[0118]

[0119] Among them, Ps j represents the orbital position data set of satellite j during the time period from the beginning to the end of the scene, s is the total number of seconds from the beginning to the end of the scene, and t i represents the time of the i-th second, represents the position of the satellite in the ECEF coordinate system at the i-th second, represents the latitude and longitude of the satellite at the i-th second;

[0120] Step 20202: Divide the orbital position data of each satellite into circles; according to the satellite orbital data Ps obtained in step 20201 j , taking the highest and lowest points of the satellite orbit latitude as the boundary, the orbit data of each satellite in the scene time are grouped, that is, traversing Ps in order j In the data, for The situation is Then perform a interception and grouping, and finally get Ps j These data represent the position set of the satellite at each moment in the half circle after it passes the equator, which is recorded as the circle group of the satellite:

[0121] Ps j ={group1,group2,group3,group4,……} j ,

[0122] in, s k ≤i≤e k , s k 、e k are the start time and end time of the kth group respectively;

[0123] Step 203: Screen the satellite's circle groups;

[0124] Step 20301: Calculate the approximate midpoint position of the regional target (lat c ,lon c ),in Then set the height to 0 and convert to the ECEF coordinate system to obtain (x c ,y c ,z c );

[0125] Step 20302: Based on the satellite circle grouping obtained in step 20202, traverse each group of data in each satellite circle group {group 1, group 2, group 3, group 4, ...};

[0126] Step 20303: Get the approximate orbit data of each group of satellites. and An ECEF position data at the position, and the x, y, z coordinates of the two positions are obtained respectively;

[0127] Step 20304: Based on the coordinate positions in the x, y, and z directions in the two ECEF coordinate systems obtained in step 20303, calculate the angle between the position and the approximate midpoint position of the regional target.

[0128]

[0129] Step 20305: If both extracted coordinate positions have a condition of θ>90°, the half-circle track corresponding to the circle group is considered to be on the other side of the spherical surface where the regional target is located, and the group in the circle group is deleted. If a coordinate position has a condition of θ<90°, the half-circle track corresponding to the circle group is considered to be on the same side of the spherical surface where the regional target is located, and the group is not deleted.

[0130] Step 20306: After traversing the circle groups and performing the deletion operation, the circle group is the half-circle set on the same side of the satellite and the target;

[0131] Step 204: Calculate the visible time window of each satellite circle in each satellite circle group to the regional target;

[0132] Step 20401: The position of the satellite at the corresponding time can be known based on the satellite circle grouping obtained in step 203;

[0133] Step 20402: Get satellite position according to step 20401 ECEF position in Combining the satellite orbit height h, the maximum roll maneuver angle β observed by the satellite, and the payload observation half-angle α, the positions of the two vertices of the satellite observation range are calculated:

[0134] and

[0135]

[0136] Step 20403: Group each circle by satellite position The two vertex sets of the observation range corresponding to the calculated position at each moment are recorded as:

[0137]

[0138] Step 20404: Vertex collection ECEF coordinates converted to latitude and longitude

[0139] Step 20405, traverse group k view The two vertices corresponding to each moment in the , determine whether the vertex is located in the region target, that is, at least one vertex (lat, lon) corresponding to each moment satisfies:

[0140]

[0141] Among them, (lat i ,lon i )∈P and (lat n+1 ,lon n+1 )=(lat1,lon1),

[0142] Step 20406: Select group k view The moment when at least one vertex is located in the region target constitutes a set {vt i}, the visible time window of each lap is [st,et], where st=min{vt i}, et = max{vt i};

[0143] Step 3: Calculate the observation strip expression of the regional target; the specific process is:

[0144] Step 301: According to the visible time window of each satellite circle to the regional target, the visible time window of each satellite circle is integrated to obtain the access window set of the satellite to the regional target within the scene time, which is recorded as represents the set of visible time windows of satellite j to regional targets in the mission scenario;

[0145] Step 302: According to the satellite orbit position information Ps j , determine the orbital position of the satellite at the start and end time of each visible time window, and obtain the ECEF coordinate position {(x s ,y s ,z s ),(x e ,y e ,z e )} and longitude and latitude {(lat s ,lon s ),(lat e ,lon e )};

[0146] Step 303: Combine the ECEF coordinate position with the longitude and latitude to obtain the satellite's orbital altitude h at the start and end of each visible time window of the target observation;

[0147] Step 304: Calculate the swath vertex position based on the satellite's orbital altitude h and longitude and latitude positions at the start and end of each visible time window for target observation, combined with the maximum roll maneuver angle β observed by the satellite and the payload observation half-angle α.

[0148] Step 30401: Calculate the projections a and b of the payload half-angle observation half-width and the satellite roll maneuver half-width on the ground, where a = h tan α and b = h tan (α + β).

[0149] Step 30402: Consider the Earth as a sphere and calculate the change in the central angle corresponding to the half-width of satellite observation and the half-width of maneuvering side swing.

[0150]

[0151] Among them, R earth is the radius of the Earth;

[0152] Step 30403: Connect the two longitude and latitude positions of the satellite at the beginning and end of the visible time window to obtain a straight line

[0153] Step 30404: (lat s ,lon s ) and (lat e ,lon e ) Two points along a straight line The vertical translation distance a' is used to obtain the observation strip vertex in the visible time window when the satellite does not perform a lateral maneuver. The translation distance b' is used to obtain the vertex of the strip where the program opportunity exists within the visible time window of the satellite. The specific formula is as follows:

[0154]

[0155] Step 30405, set the strip selection parameter φ, φ∈[-1,1], and select the observation strip vertex as

[0156]

[0157] Step 4: Genetic algorithm task planning step; the specific process is:

[0158] Step 401: Encode the chromosome; suppose there are N satellites in total, and the i-th satellite has W i visible time windows, each chromosome needs Gene bits, each gene bit can be a null value to indicate that the satellite does not perform observations in this time window, and φ∈[-1,1] to indicate that the satellite performs observations and is selected in the observation strips of the visible time window;

[0159] Step 402: randomly generate multiple chromosomes according to the encoding method of step 401 and initialize the population;

[0160] Step 403: Calculate the fitness of each individual in the population:

[0161] Step 40301: Calculate the observation coverage area based on the intersection of the rectangle formed by the observation strip vertices selected by each satellite in its visible time window and the area to be observed. Sum the coverage area of each window to obtain the observation coverage area of the mission planning scheme represented by the i-th individual. i ;

[0162] Step 40302: Calculate the overlapping area of multiple rectangles based on the rectangles formed by the observation strip vertices selected by each satellite in its visible time window, and sum up each overlapping area to obtain the observation overlapping area Overlap of the mission planning scheme represented by the i-th individual. i ;

[0163] Step 40303: Obtain the maneuvering attitude angle abs(φ)·β of each satellite in its visible time window according to the genetic coding number. Assuming that the energy consumed by satellite attitude conversion is proportional to the attitude conversion angle, the sum of the maneuvering attitude angles of each satellite in the visible time window is calculated. The energy consumption of the posture maneuver of the task planning scheme represented by the i-th individual can be obtained;

[0164] Step 40304: Calculate the fitness of the i-th individual. The fitness function is:

[0165]

[0166] Among them, Area P is the total area of the region to be observed, τ1, τ2, τ3 are constant coefficients with τ1>0, τ2<0, τ3<0, Φ is the function Φ(λ)=exp(λ);

[0167] Step 404: Select the individual with the highest fitness in the population and record it;

[0168] Step 405: Randomly select individuals for crossover and mutation:

[0169] Step 40501: Randomly select two individuals and randomly select a position, and exchange the genetic codes after the position between the two individuals;

[0170] Step 40502: Randomly select an individual, randomly select a position where the gene code is empty and add a random number [-1, 1];

[0171] Step 40503: Randomly select an individual, randomly select a position with a genetic code, and replace the number at that position with another random number in the range [-1, 1];

[0172] Step 406: Repeat the crossover and mutation operations and record the individual with the best fitness. After reaching the number of iterations, the individual with the best fitness is obtained.

[0173] Step 407: Decode the best fitness individual to obtain a task planning solution:

[0174] Step 40701: segment the gene according to the number of visible time windows of each satellite. The i-th segment corresponds to the visible time window of satellite i. The visible time window of satellite i has W i Then the gene segment has W i gene loci;

[0175] Step 40702: Each gene position containing a number is considered to be performing observation in the visible time window, and the roll maneuver angle during satellite observation is φ·β.

[0176] Specific embodiment 2: A constellation-to-earth regional target observation mission planning device, comprising a module for screening mission-performing satellites, a module for calculating a regional target visible time window, a module for calculating an observation strip expression of a regional target, and a genetic algorithm mission planning module;

[0177] Screening module for satellites that can perform missions: preliminarily screen satellites that can perform missions;

[0178] Regional target visibility time window calculation module: This module decomposes the satellite's orbital circles, selects the circle set on the same side as the regional target, and then determines whether the visible range overlaps with the regional target to calculate the visibility time window;

[0179] Observation strip expression calculation module for regional targets: calculates the satellite observation range by calculating the visible time window and satellite position information, and constructs the observation strip expression based on strip selection parameters;

[0180] Genetic algorithm mission planning module: Chromosome encoding of multiple visible time windows of each satellite, and intelligent search of satellite observation time window selection and imaging posture.

[0181] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for planning a satellite constellation mission to observe a target in an earth region, characterized in that: The specific steps include: Step 1: Screening the satellites to perform the mission; screening the satellites to perform the mission based on the parameters of each satellite in the constellation and the target information; Step 2: Calculate the satellite's visible time window for the regional target. Based on the decomposition of the satellite's orbital circles, calculate and filter out the circle set on the same side as the regional target. Based on the vertex of the satellite's visible range at each moment, determine whether the visible range overlaps with the regional target and calculate the visible time window. Step 3: Calculate the observation strip expression of the regional target; calculate the satellite observation range according to the visible time window and the satellite position information, and select a specific observation strip within the observation range corresponding to the visible time window based on the strip selection parameter; Step 4, genetic algorithm task planning step: Based on the chromosome encoding of multiple visible time windows of each satellite, an improved evaluation function is used to perform intelligent search for the satellite's observation time window selection and imaging attitude.

2. The method for planning a satellite constellation mission to observe a target in an earth region according to claim 1, characterized in that: The process of selecting satellites to perform missions in step 1 is as follows: Step 101: Determine the satellite payloads required to perform the observation mission based on the mission observation requirements provided by the user, remove satellite platforms that do not have the corresponding payloads from the constellation resources, and use the remaining satellites to form a satellite set capable of performing the mission. Step 102: Determine the latitude and longitude position range of the regional target; Step 103: Calculate the satellite observation range based on the satellite orbit data.

3. The method for planning a satellite constellation mission to observe a target in an earth region according to claim 2, wherein: The step of determining the latitude and longitude position range of the regional target in step 102 includes: Step 10201: Use multiple vertices to represent the area target. The vertices are arranged in a clockwise direction and are denoted as P = {p i |lat i ,lon i },1≤i≤n, where lat i Represents vertex p i Latitude, lon i Represents vertex p i The longitude of , n is the number of vertices; Step 10202: Select the minimum and maximum latitude and longitude values in the vertex set, and record them as lat min ,lat max ,lon min ,lon max .

4. The method for planning a satellite constellation mission to observe a target in an earth region according to claim 2, wherein: The step of calculating the satellite observation range based on the satellite orbit data in step 103 includes: Step 10301: Read the orbital parameters and payload parameters of each satellite in the set of satellites that can execute the mission, and obtain the satellite's orbital inclination i, maximum roll maneuver angle β, and payload observation half-angle α. Step 10302: Eliminate satellites that have no observation opportunities. Assuming the maximum observation range of a satellite is γ, where γ = α + β, then its maximum latitude coverage of the Earth is: [-|i|-η,|i|+η], in If the regional target is at a higher latitude, that is: There is no imaging opportunity for the satellite, and the visible window calculation is not performed. The satellite platform is directly deleted from the set of satellites that can execute the mission.

5. A method for planning a satellite constellation mission to observe a target in an earth region according to claim 1 or 4, characterized in that: The process of calculating the satellite visibility time window for regional targets in step 2 is as follows: Step 201: Set the start and end time of the regional target observation mission scene; Step 202: Decomposing the orbits of mission-capable satellites; specifically, the following steps are performed: Step 20201: Based on the set of satellites capable of executing the mission described in step 10302, obtain the orbital position data of each satellite during the time period from the beginning to the end of the scene; record the orbital data of each satellite as: Among them, Ps j represents the orbital position data set of satellite j during the time period from the beginning to the end of the scene, s is the total number of seconds from the beginning to the end of the scene, and t i represents the time of the i-th second, represents the position of the satellite in the ECEF coordinate system at the i-th second, represents the latitude and longitude of the satellite at the i-th second; Step 20202: Divide the orbital position data of each satellite into circles; according to the satellite orbital data Ps obtained in step 20201 j , taking the highest and lowest points of the satellite orbit latitude as the boundary, the orbit data of each satellite in the scene time are grouped, that is, traversing Ps in order j In the data, for The situation is Then perform a interception and grouping, and finally get Ps j These data represent the position set of the satellite at each moment in the half circle after it passes the equator, which is recorded as the circle group of the satellite: Ps j ={group1,group2,group3,group4,……} j , in, s k 、e k are the start time and end time of the kth group respectively; Step 203: Screen the satellite's circle groups; Step 20301: Calculate the approximate midpoint position of the regional target (lat c ,lon c ),in Then set the height to 0 and convert to the ECEF coordinate system to obtain (x c ,y c ,z c ); Step 20302: Based on the satellite circle grouping obtained in step 20202, traverse each group of data in each satellite circle group {group 1, group 2, group 3, group 4, ...}; Step 20303: Get the approximate orbit data of each group of satellites. and An ECEF position data at the position, and the x, y, and z coordinates of the two positions are obtained respectively; Step 20304: Based on the coordinate positions in the x, y, and z directions in the two ECEF coordinate systems obtained in step 20303, calculate the angle between the position and the approximate midpoint position of the regional target. Step 20305: If both extracted coordinate positions have a condition of θ>90°, the half-circle track corresponding to the circle group is considered to be on the other side of the spherical surface where the regional target is located, and the group in the circle group is deleted. If a coordinate position has a condition of θ<90°, the half-circle track corresponding to the circle group is considered to be on the same side of the spherical surface where the regional target is located, and the group is not deleted. Step 20306: After traversing the circle groups and performing the deletion operation, the circle group is the half-circle set on the same side of the satellite and the target; Step 204: Calculate the visible time window of each satellite circle in each satellite circle group to the regional target; Step 20401: The position of the satellite at the corresponding time can be known based on the satellite circle grouping obtained in step 203; Step 20402: Get satellite position according to step 20401 ECEF position in Combining the satellite orbit height h, the maximum roll maneuver angle β observed by the satellite, and the payload observation half-angle α, the positions of the two vertices of the satellite observation range are calculated: and Step 20403: Group each circle by satellite position The two vertex sets of the observation range corresponding to the calculated position at each moment are recorded as: Step 20404: Vertex collection ECEF coordinates converted to latitude and longitude Step 20405, traverse group k view The two vertices corresponding to each moment in the , determine whether the vertex is located in the region target, that is, at least one vertex (lat, lon) corresponding to each moment satisfies: Among them, (lat i ,lon i )∈P and (lat n+1 ,lon n+1 )=(lat1,lon1), Step 20406: Select group k view The moment when at least one vertex is located in the region target constitutes a set {vt i }, the visible time window of each lap is [st,et], where st=min{vt i }, et = max{vt i }.

6. The method for planning a satellite constellation mission to observe a target in an earth region according to claim 1, wherein: The process of calculating the observation strip expression of the regional target in step 3 is as follows: Step 301: According to the visible time window of each satellite circle to the regional target, the visible time window of each satellite circle is integrated to obtain the access window set of the satellite to the regional target within the scene time, which is recorded as represents the set of visible time windows of satellite j to regional targets in the mission scenario; Step 302: According to the satellite orbit position information Ps j , determine the orbital position of the satellite at the start and end time of each visible time window, and obtain the ECEF coordinate position {(x s ,y s ,z s ),(x e ,y e ,z e )} and longitude and latitude {(lat s ,lon s ),(lat e ,lon e )}; Step 303: Combine the ECEF coordinate position with the longitude and latitude to obtain the satellite's orbital altitude h at the start and end of each visible time window of the target observation; Step 304: Calculate the swath vertex position based on the satellite's orbital altitude h and longitude and latitude positions at the start and end of each visible time window for target observation, combined with the maximum roll maneuver angle β observed by the satellite and the payload observation half-angle α. Step 30401: Calculate the projections a and b of the payload half-angle observation half-width and the satellite roll maneuver half-width on the ground, where a = htanα, b = htan(α + β); Step 30402: Consider the Earth as a sphere and calculate the change in the central angle corresponding to the half-width of satellite observation and the half-width of maneuvering side swing. Among them, R earth is the radius of the Earth; Step 30403: Connect the two longitude and latitude positions of the satellite at the beginning and end of the visible time window to obtain a straight line Step 30404: (lat s ,lon s ) and (lat e ,lon e ) Two points along a straight line The vertical translation distance a' is used to obtain the observation strip vertex in the visible time window when the satellite does not perform a lateral maneuver. The translation distance b' is used to obtain the vertex of the strip where the program opportunity exists within the visible time window of the satellite. The specific formula is as follows: Step 30405, set the strip selection parameter φ, φ∈[-1,1], and select the observation strip vertex as 7. The method for planning a satellite constellation mission to observe a target in an earth region according to claim 1, wherein: The process of the genetic algorithm task planning step in step 4 is called: Step 401: Encode the chromosome; suppose there are N satellites in total, and the i-th satellite has W i visible time windows, each chromosome needs Gene bits, each gene bit can be a null value to indicate that the satellite does not perform observations in this time window, and φ∈[-1,1] to indicate that the satellite performs observations and is selected in the observation strips of the visible time window; Step 402: randomly generate multiple chromosomes according to the encoding method of step 401 and initialize the population; Step 403: Calculate the fitness of each individual in the population: Step 40301: Calculate the observation coverage area based on the intersection of the rectangle formed by the observation strip vertices selected by each satellite in its visible time window and the area to be observed. Sum the coverage area of each window to obtain the observation coverage area of the mission planning scheme represented by the i-th individual. i ; Step 40302: Calculate the overlapping area of multiple rectangles based on the rectangles formed by the observation strip vertices selected by each satellite in its visible time window, and sum up each overlapping area to obtain the observation overlapping area Overlap of the mission planning scheme represented by the i-th individual. i ; Step 40303: Obtain the maneuvering attitude angle abs(φ)·β of each satellite in its visible time window according to the genetic coding number. Assuming that the energy consumed by satellite attitude conversion is proportional to the attitude conversion angle, the sum of the maneuvering attitude angles of each satellite in the visible time window is calculated. The energy consumption of the posture maneuver of the task planning scheme represented by the i-th individual can be obtained; Step 40304: Calculate the fitness of the i-th individual. The fitness function is: Among them, Area P is the total area of the region to be observed, τ1, τ2, τ3 are constant coefficients with τ1>0, τ2<0, τ3<0, Φ is the function Φ(λ)=exp(λ); Step 404: Select the individual with the highest fitness in the population and record it; Step 405: Randomly select individuals for crossover and mutation: Step 40501: Randomly select two individuals and randomly select a position, and exchange the genetic codes after the position between the two individuals; Step 40502: Randomly select an individual, randomly select a position where the gene code is empty and add a random number [-1, 1]; Step 40503: Randomly select an individual, randomly select a position with a genetic code, and replace the number at that position with another random number in the range [-1, 1]; Step 406: Repeat the crossover and mutation operations and record the individual with the best fitness. After reaching the number of iterations, the individual with the best fitness is obtained. Step 407: Decode the best fitness individual to obtain a task planning solution: Step 40701: segment the gene according to the number of visible time windows of each satellite. The i-th segment corresponds to the visible time window of satellite i. The visible time window of satellite i has W i Then the gene segment has W i gene loci; Step 40702: Each gene position containing a number is considered to be performing observation in the visible time window, and the roll maneuver angle during satellite observation is φ·β.

8. A satellite constellation mission planning device for observing targets in the earth's region, characterized in that: It includes a module for screening satellites to perform missions, a module for calculating the visible time window of regional targets, a module for calculating the observation strip expression of regional targets, and a module for genetic algorithm mission planning; Screening module for satellites that can perform missions: preliminarily screen satellites that can perform missions; Regional target visibility time window calculation module: This module decomposes the satellite's orbital circles, selects the circle set on the same side as the regional target, and then determines whether the visible range overlaps with the regional target to calculate the visibility time window; Observation strip expression calculation module for regional targets: calculates the satellite observation range by calculating the visible time window and satellite position information, and constructs the observation strip expression based on strip selection parameters; Genetic algorithm mission planning module: Chromosome encoding of multiple visible time windows of each satellite, and intelligent search of satellite observation time window selection and imaging posture.

Images