Adaptive discretization decomposition method and device for satellite observation planning of regional target

Abstract

The application discloses a satellite adaptive discretization decomposition method and device for regional target observation planning, belongs to the field of space technology, and particularly relates to a strip decomposition of a satellite for a regional target. The method comprises the following steps: determining a discretization step of a regional target according to an observation range of a satellite load; and discretizing the regional target into a regional sub-node set based on the discretization step and the shape of the earth. The regional sub-node set comprises a plurality of sub-nodes. The satellite adaptive discretization decomposition method and device for regional target observation planning are suitable for single or multiple earth observation satellites to plan and calculate observation tasks for a single or multiple irregularly shaped regional targets.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aerospace technology, in particular to a satellite strip decomposition of a regional target. BACKGROUND

[0002] In recent years, with the development of space information technology, a multi-satellite joint observation planning system is formed by different types, different types and different purposes of multiple earth observation satellites. In order to improve the working efficiency of the satellite and the utilization rate of the satellite payload, the observation task of the satellite system is optimized and the operation cost is reduced, and the satellite task planning is needed to develop an efficient observation task plan.

[0003] Because the satellite runs at a certain orbit height, the field angle of the satellite-borne remote sensor is limited, and the remote sensor can only observe a limited ground area at the same time. For a larger regional target on the ground, it cannot be covered by a single observation strip of the satellite, and before the satellite observation, the regional target must be decomposed into multiple observation strips, that is, the regional target is decomposed into a single task that can be executed by the satellite. The way of regional decomposition determines the observation efficiency of the satellite on the regional target in a certain sense, and it is of great significance to study efficient regional target decomposition technology. Therefore, it is necessary to develop an efficient regional target decomposition method to improve the observation efficiency of the multi-satellite.

[0004] At present, the method for decomposing the regional target mainly uses geometric algorithm to calculate the observation strip, collects the area, intersection and position of the region and other related geometric data to determine the observation decomposition and area coverage of the regional target. The existing regional target decomposition method has the problem of long calculation time when facing irregular polygon regions.

[0005] In summary, with the increase of the number of satellites and targets involved in satellite task planning and the diversification of regional targets, how to speed up the satellite visibility operation speed for regional targets and provide timely optional solutions for subsequent satellite task planning is a problem that needs to be solved. SUMMARY

[0006] The present application provides a satellite regional target observation planning adaptive discretization decomposition method and device, which solves the problem of long calculation time and low efficiency of satellite visibility coverage and observation strip decomposition of the existing regional target decomposition method.

[0007] The satellite regional target observation planning adaptive discretization decomposition method provided by the present application comprises the following steps:

[0008] Step of determining step length: determining the discretization step length of the regional target according to the observation range of the satellite payload;

[0009] The step of discretizing into a set of sub-nodes: discretizing the regional target into a set of regional sub-nodes based on a discretization step and the shape of the earth; the set of regional sub-nodes includes a plurality of sub-nodes;

[0010] The step of calculating the minimum observation elevation angle: calculating the minimum observation angle of each sub-node in the regional target by the satellite in each orbit and the target sub-nodes with observation opportunities in each orbit;

[0011] The step of grouping sub-nodes: constructing a strip interval and grouping all target sub-nodes according to the minimum observation angle and the target sub-nodes;

[0012] The step of merging strips: merging the target sub-nodes into strips according to the grouping of all target sub-nodes, and using the convex hull algorithm to obtain the vertex position of the strip and the time window of the satellite observation of each group of strips.

[0013] Further, a preferred embodiment is provided, wherein the step of determining the step includes the following steps:

[0014] Step 1.1: Determine the observation range of the satellite payload:

[0015] The earth observation satellite is classified according to the observation range of the payload, which is divided into conical field of view and rectangular field of view payload; wherein the conical field of view payload has the same field of view angle in each direction, and the rectangular field of view payload has different opening angles in two perpendicular directions;

[0016] Let the satellite orbit minimum height be h, the half opening angle of the conical field of view payload be α1, the half opening angle of the rectangular field of view payload perpendicular to the satellite forward direction be α2, and the half opening angle of the rectangular field of view payload parallel to the satellite forward direction be β;

[0017] Then the circular radius of the conical field of view payload on the ground projection is R, and the rectangular side length of the rectangular field of view payload on the ground projection is 2L1 and 2L2; wherein R = h tan α1, L1 = h tan α2, L2 = h tan β;

[0018] Step 1.2: Calculate the discretization step of the regional target:

[0019] Let the discretization step of the regional target be d, which is determined by the minimum observation range of the satellite payload;

[0020] For the conical field of view payload,

[0021] For the rectangular field of view payload,

[0022] Further, a preferred embodiment is provided, wherein the step of discretizing into a set of sub-nodes includes the following steps:

[0023] Step 2.1: Determine the position of each vertex of the target area:

[0024] Determine the n vertices of the target area to be observed, with the vertex positions represented by latitude and longitude, denoted as Points = [lat, lon]. n , where lat represents latitude and lon represents longitude;

[0025] Let the maximum latitude of the vertex be lat. max The minimum latitude of the vertex is lat. min The maximum longitude of the vertex is lon. max The minimum longitude of the vertex is lon. min ;

[0026] Step 2.2: Use child nodes to cover the target area:

[0027] Step 2.2.1: Based on the latitude and longitude range of the vertices of the regional target described in Step 2.1, calculate the longitude set of the child nodes:

[0028] From the vertex corresponding to the minimum longitude and minimum latitude [lat min ,lon min Starting from point ], add child nodes one by one in the same latitude and high longitude direction with a step size of d; during each addition of a child node:

[0029] Let the longitude of the starting point be lon0 and the latitude be lat0. The radius of the Earth's latitude circle corresponding to this latitude is...

[0030]

[0031] Where a is the Earth's major axis; b is the Earth's minor axis (polar radius);

[0032] The longitude of the new child node obtained by moving it towards a higher longitude at the same latitude is lon1:

[0033]

[0034] Repeat adding child nodes until the longitude of the new child node is greater than or equal to lon. max , obtain the longitude set of the child nodes;

[0035] Step 2.2.2: Based on the latitude and longitude range of the vertices of the regional target described in Step 2.1, spread the longitude set of the child nodes obtained in Step 2.2.1 towards higher latitudes, so that the child nodes cover the regional target:

[0036] Starting with each child node in the longitude set, add child nodes one by one towards higher latitudes at the same longitude; during each addition of a child node:

[0037] Let the longitude of the starting point be lon0', the latitude be lat0', and the latitude of the new child node obtained by moving in the same longitude and high latitude direction be lat1;

[0038]

[0039] wherein, is the Earth's flattening;

[0040] Repeat the addition of child nodes until the latitude of the new child node is greater than or equal to lat max , and obtain the longitude and latitude set of the child nodes;

[0041] Step 2.3: Remove the child nodes located outside the area target to obtain the area child node set:

[0042] Step 2.3.1: According to the longitude and latitude set of the child nodes obtained in step 2.2, traverse each child node in the longitude and latitude set of the child nodes to obtain the longitude and latitude position of each child node;

[0043] Let any one of the child nodes in the longitude and latitude set of the child nodes be node k ;

[0044] Step 2.3.2: Obtain the number of intersection points of the right ray of the child node with the boundary line of the area target:

[0045] For each boundary line of the area target, the two endpoints of the boundary line are denoted as point i and point j ;

[0046] For the child node with a latitude between the latitudes of the two endpoints of the boundary line, if the child node is on the left side of the boundary line composed of the two endpoints, it is considered that the right ray of the child node intersects the boundary line once; wherein:

[0047] If the condition is met, it is considered that the latitude of the child node node k is between the latitudes of the two endpoints of the boundary line;

[0048] If the condition is met, it is considered that the child node node k is on the left side of the boundary line, and it is considered that the right ray of the child node node k intersects the boundary line composed of the two endpoints point i and point j once;

[0049] Step 2.3.3: Determine whether the child node is within the area target according to the number of intersection points obtained in step 2.3.2;

[0050] Iterate through each child node in the set of latitude and longitude coordinates of the child nodes:

[0051] If any child node k If the number of intersections between the rightward ray and the boundary line of the target area is even, then the child node is... k Outside of regional objectives;

[0052] Remove all child nodes outside the target area from the child node latitude and longitude set to obtain the set of child nodes in the region, denoted as Nodes.

[0053] Furthermore, a preferred embodiment is provided, wherein the step of calculating the minimum observation elevation angle includes the following steps:

[0054] Step 3.1: Set the start and end times for the observation task scenario of the area target;

[0055] Step 3.2: Use the orbit recursion algorithm to calculate the latitude, longitude, and altitude data of the satellite's orbit per second under the observation mission scenario;

[0056] Let the latitude, longitude, and altitude data of the satellite's orbit per second be LLA={lla0,lla1,…,lla j , ...}; where, lla j This is a sample of the latitude, longitude, and altitude data of the satellite in orbit at the j-th second.

[0057] lla j ={lat′ j ,lon′ j ,alt′ j};

[0058] Among them, lat j ′ represents lla j latitude value, lon j ′ represents lla j longitude value, alt j ′ represents lla j The height value;

[0059] Step 3.3: Lap Division:

[0060] Latitude, longitude, and altitude data per second for traversing satellite orbits:

[0061] When (lat) j ′-lat0′)·(lat j ′ +1 When -lat0′)<0, lla j The indicated position is marked as the end of the current lap, lla j+1The represented position is recorded as the start of the next orbit, and the orbital data of the satellite for each orbit is obtained;

[0062] Step 3.4: Calculate the overall geometric visible time window of the satellite for all sub-nodes in the regional target in each orbit:

[0063] Step 3.4.1: In each orbit, the height value of the satellite on the orbit is alt, and the radius of the earth is R e , then the distance from the satellite to the center of the earth is R Sat = R e + alt;

[0064] Step 3.4.2: Calculate the maximum range of the satellite for the geometric visibility of any sub-node in the regional target on the surface of the earth, and the opening angle is η:

[0065]

[0066] , then the central angle of the satellite for any sub-node in the regional target is

[0067] Step 3.4.3: Calculate the overall geometric visible time window of the satellite for all sub-nodes in the regional target by binary search method:

[0068] In each orbit, the initial step size is used to perform binary search method, based on the opening angle η to determine whether the satellite is in the geometric visible time window, and the time data of the start position and the end position of the geometric visible time window of the satellite for any sub-node in the regional target is obtained; wherein, represents the upward rounding;

[0069] In each orbit, the time data of the start position and the end position of the geometric visible time window of the satellite for each sub-node in the regional target is combined, and the earliest start time and the latest end time is selected, and the overall geometric visible time window of the satellite for all sub-nodes in the regional target is obtained, which is called the overall geometric visible time window;

[0070] Step 3.5: Based on the overall geometric visible time window of the satellite for all sub-nodes in the regional target, calculate the minimum observation angle of the satellite for each sub-node in the regional target in each orbit:

[0071] Step 3.5.1: Calculate the expression of the horizon line;

[0072] In each orbit of the satellite, the longitude and latitude of the two nadir points in the start position and the end position of the overall geometric visible time window are obtained;

[0073] According to the longitude and latitude of the two nadir points, the expression of the horizon line is:

[0074]

[0075] in, The longitude of the nadir point at the beginning of the overall geometrically visible time window; The latitude of the nadir point at the beginning of the overall geometrically visible time window; The longitude of the nadir point at the end of the overall geometrically visible time window; The latitude of the nadir point at the end of the overall geometrically visible time window;

[0076] Step 3.5.2: Calculate the position of the foot of the perpendicular line drawn from each child node in the set of child nodes in the region to the lower star line:

[0077] Solve the following two equations simultaneously:

[0078]

[0079] Based on the result of the joint equation, any child node can be obtained. k Position of the foot of the perpendicular line drawn from the lower star:

[0080]

[0081] The sub-star point position corresponding to the perpendicular position is any child node. k The corresponding nearest sub-satellite point position is used to obtain the satellite orbit position lla corresponding to the perpendicular position. s ;

[0082] Step 3.5.3: Obtain the minimum observation angle for each child node within the target area:

[0083] The satellite orbit position corresponding to the vertical foot position is 1a s Representation in Earth-centered, Earth-fixed coordinate system: ecef(lla) s );

[0084] any child node k Representation in Earth-centered, Earth-fixed coordinate system: ecef(node) k );

[0085] Then the satellite can monitor any child node within the target area. k The minimum observation angle is ξ k :

[0086]

[0087] Step 3.6: Based on the overall geometric visibility time window of the satellite for all sub-nodes within the regional target area, calculate the target sub-nodes with observation opportunities in each orbit, and the payload visibility time window of the satellite for the regional target area:

[0088] Step 3.6.1: Obtain the time interval between the earliest start time and the latest end time of the overall geometrically visible time window, and obtain the latitude and longitude data of the satellite's orbit per second within this time interval based on the orbital extrapolation data.

[0089] Step 3.6.2: Traverse the satellites in each orbit and examine any child node within the target area. k Minimum observation angle ξ k :

[0090] If ξ k If ≤α+ω, then any corresponding child node node k The target sub-node; the satellite has the opportunity to observe the target sub-node;

[0091] Where ω is the maximum maneuvering side angle of the satellite; α is the half-angle, for the load of the conical field of view, α=α1, for the load of the rectangular field of view, α=α2;

[0092] Step 3.6.3: Obtain the satellite orbit position lla corresponding to the target child node. s '; Reference latitude and longitude data From satellite orbital position lla s 'Determine the scenario time when the satellite has an opportunity to observe the target sub-nodes;'

[0093] Step 3.6.4: Select the earliest and latest times from the scene times when the satellite has the opportunity to observe all target sub-nodes in each orbit. The time window between the two times is the time window when the satellite's payload is visible to the regional target in each orbit.

[0094] Furthermore, in a preferred embodiment, the child node grouping step includes the following steps:

[0095] Step 4.1: Find the minimum observation angle ξ corresponding to the target sub-nodes for which the satellite has an observation opportunity in each orbit. k 'Process:'

[0096] Determine the positional relationship between the target sub-node and the nadir line. If the target sub-node is located to the left of the nadir line, then the minimum observation angle ξ is... k 'Take a negative value, otherwise the value remains unchanged:'

[0097]

[0098] Among all target child nodes, let ξk The minimum value of ' is ξ min ξ k The maximum value of ' is ξ max ;

[0099] Step 4.2: Using ξ min The corresponding target sub-node is the starting point, 2α is the step size, and ξ is the y-axis. max Using the corresponding target sub-nodes as endpoints, construct strip intervals, and divide all target sub-nodes into segments according to the satellite imaging side sway angle. Groups:

[0100] [ξ min ,ξ min +2α],[ξ min +2α,ξ min +4α],......,[...,ξ max ];

[0101] The average of the minimum observation angles at both ends of each group is the side sway angle of the satellite imaging for each group.

[0102] Furthermore, in a preferred embodiment, the merging strips step includes the following steps:

[0103] Step 5.1: Merge the target child nodes of each group using the convex hull algorithm to obtain the vertex positions of the strips corresponding to each group of target child nodes;

[0104] Step 5.2: Use the payload visibility time window of each group of target sub-nodes as the time window for satellite observation of each group of strips;

[0105] Step 5.3: The ratio of the number of target sub-nodes included in each strip group to the total number of target sub-nodes in the region is taken as the target coverage rate of each strip group.

[0106] This invention also proposes an adaptive discretization decomposition device for satellite observation planning of regional targets, the device comprising the following modules:

[0107] Step size determination module: Determines the discretization step size of regional targets based on the observation range of the satellite payload;

[0108] Discretization into a set of sub-nodes module: Based on the discretization step size and the shape of the Earth, the regional target is discretized into a set of regional sub-nodes; the set of regional sub-nodes includes multiple sub-nodes;

[0109] Minimum observation elevation angle calculation module: calculates the minimum observation angle of the satellite for each sub-node within the regional target in each orbit and the target sub-nodes for which the satellite has an observation opportunity in each orbit;

[0110] The child node grouping module: according to the minimum observation angle and the target child node, a strip interval is constructed and all target child nodes are grouped;

[0111] The strip merging module: according to the grouping condition of all target child nodes, the target child nodes are merged into strips, and the vertex position of the strip and the time window for observing each group of strips by the satellite are calculated by using the convex hull algorithm.

[0112] The application further provides a computer system, comprising a processor and a memory, wherein the memory is used for storing executable instructions of the processor, and the processor is configured to execute the adaptive discretization decomposition method for satellite pair regional target observation planning according to any one of the above.

[0113] The application further provides a computer storage medium, wherein the computer storage medium stores a computer program, and the computer program is used to execute the adaptive discretization decomposition method for satellite pair regional target observation planning according to any one of the above.

[0114] The application further provides a computer program product, comprising a computer program / instruction, and the computer program / instruction is used to execute the steps of the adaptive discretization decomposition method for satellite pair regional target observation planning according to any one of the above.

[0115] The application has the following beneficial effects:

[0116] 1. The adaptive discretization decomposition method and device for satellite pair regional target observation planning have the following beneficial effects: the adaptive discretization method based on the observation range of a satellite load is used to discretize the regional target to be observed into regional child nodes; the minimum observation angle of the satellite pair regional child nodes is used to represent the observation condition of the satellite pair target; the regional child nodes are merged into strips according to the minimum observation angle required by the regional child nodes, and the determination of the time window for satellite strip observation is performed, so as to provide a reference for subsequent task planning.

[0117] 2. The adaptive discretization decomposition method and device for satellite pair regional target observation planning have the following beneficial effects: the step length of the discretization of the regional target is determined according to the detection range of the satellite load, so as to adapt to different observation loads of different satellites; the continuous regional target is discretized into child nodes for separate calculation of the observation condition, so as to reduce the complexity of the calculation, and the position of the child node is determined according to the original regional range and the discretization step length and by referring to the shape of the earth; through the discretization processing, the use of a complex geometric algorithm for calculation of the coverage condition is avoided, so as to accelerate the solving efficiency.

[0118] The satellite regional target observation planning adaptive discretization decomposition method and device are suitable for single or multiple earth observation satellites to plan and calculate the observation of single or multiple irregularly shaped regional targets. BRIEF DESCRIPTION OF DRAWINGS

[0119] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0120] Figure 1 For an embodiment of the present application, a schematic diagram of the field of view payload observation effect is shown in the figure.

[0121] Figure 2 For an embodiment of the present application, a schematic diagram of the regional target discretization process is shown in the figure.

[0122] Figure 3 For an embodiment of the present application, a schematic diagram of the satellite geometric visibility time window of any sub-node in the regional target is shown in the figure.

[0123] Figure 4 For an embodiment of the present application, a schematic diagram of the minimum observation angle of the satellite to any sub-node in the regional target is shown in the figure.

[0124] Figure 5 For an embodiment of the present application, a schematic diagram of the target sub-node synthesized strip is shown in the figure. DETAILED DESCRIPTION

[0125] In order to make the technical solutions and advantages of the present application clearer, the specific embodiments of the present application will be further described in detail in combination with the drawings. The various embodiments described below are only some preferred schemes of the present application, but not all the embodiments; the various embodiments described below are intended to explain the present application, and cannot be understood as limiting the present application; the reasonable combination of the technical features defined in the various embodiments of the present application, and all other embodiments obtained by those skilled in the art without any creative effort on the basis of the embodiments of the present application, all belong to the protection scope of the present application.

[0126] In an embodiment, a satellite regional target observation planning adaptive discretization decomposition method is provided, and the method comprises the following steps:

[0127] Step of determining step length: determining the discretization step length of the regional target according to the observation range of the satellite payload;

[0128] The step of discretizing into a set of sub-nodes: discretizing the regional target into a set of regional sub-nodes based on a discretization step and the shape of the earth; the set of regional sub-nodes includes a plurality of sub-nodes;

[0129] The step of calculating the minimum observation elevation angle: calculating the minimum observation angle of each sub-node in the regional target by the satellite in each orbit pass and the target sub-nodes having observation opportunities in each orbit pass;

[0130] The step of grouping sub-nodes: constructing a strip interval and grouping all target sub-nodes according to the minimum observation angle and the target sub-nodes;

[0131] The step of merging strips: merging the target sub-nodes into strips according to the grouping of all target sub-nodes and calculating the vertex position of the strips and the time window of the observation of each group of strips by the satellite using a convex hull algorithm.

[0132] In addition, in an embodiment, the step of determining the step includes the following steps:

[0133] Step 1.1: determining the observation range of the satellite payload:

[0134] The earth observation satellite is classified according to the observation range of the payload into a conical field of view and a rectangular field of view; wherein the conical field of view has the same field of view angle in each direction, and the rectangular field of view has different angles in two perpendicular directions;

[0135] Let the minimum height of the satellite orbit be h, the half angle of the conical field of view be α1, the half angle of the rectangular field of view perpendicular to the satellite forward direction be α2, and the half angle of the rectangular field of view parallel to the satellite forward direction be β;

[0136] Then the radius of the ground projection of the conical field of view is R, and the length of the ground projection of the rectangular field of view is 2L1 and 2L2; wherein R = h·tanα1, L1 = h·tanα2, L2 = h·tanβ;

[0137] Step 1.2: calculating the discretization step of the regional target:

[0138] Let the discretization step of the regional target be d, which is determined by the minimum observation range of the satellite payload;

[0139] For the conical field of view,

[0140] For the rectangular field of view,

[0141] In this embodiment, as Figure 1The schematic diagram of the field of view payload observation effect is shown, and it can be seen from the diagram that the observation range of different types of payload; the ground projection radius of the conical field of view payload is R; the ground projection side length of the rectangular field of view payload is 2L1 and 2L2.

[0142] In addition, in an embodiment, in the step of discretizing the region target into a set of region sub-nodes based on the discretization step and the shape of the earth, the region target is discretized into a set of region sub-nodes; the set of region sub-nodes includes a plurality of sub-nodes, including the following steps:

[0143] Step 2.1: Determine the position of each vertex of the region target:

[0144] Determine the n vertices of the region target to be observed, and the vertex position is expressed by latitude and longitude, denoted as Points=[lat,lon] n , wherein lat represents latitude, and lon represents longitude;

[0145] Let the maximum latitude of the vertex be lat max , the minimum latitude of the vertex be lat min , the maximum longitude of the vertex be lon max , and the minimum longitude of the vertex be lon min .

[0146] Step 2.2: Use sub-nodes to cover the region target:

[0147] Step 2.2.1: According to the latitude and longitude range of the vertex of the region target in step 2.1, calculate the longitude set of the sub-node:

[0148] Start from the vertex [lat min ,lon min ] corresponding to the minimum longitude and latitude, and add sub-nodes in the direction of the same latitude and high longitude with a step size of d; in the process of adding each sub-node:

[0149] Let the longitude of the starting point be lon0, and the latitude be lat0, and the latitude corresponds to the radius of the earth latitude circle R lat0 .

[0150]

[0151] , wherein a is the major axis of the earth; b is the minor axis of the earth (polar radius);

[0152] The longitude of the new sub-node obtained by moving in the direction of the same latitude and high longitude is lon1:

[0153]

[0154] repeat adding child nodes until the longitude of the new child node is greater than or equal to lon max , obtaining the longitude set of the child nodes;

[0155] Step 2.2.2: Based on the longitude set of the child nodes obtained in step 2.2.1, spread in the high-latitude direction according to the longitude and latitude range in which the vertices of the area target in step 2.1 are located, so that the child nodes cover the area target:

[0156] Start with each child node in the longitude set respectively, and add child nodes one by one in the same longitude high-latitude direction; in the process of adding each child node:

[0157] Let the longitude of the starting point be lon0' and the latitude be lat0', and the latitude of the new child node obtained by moving in the same longitude high-latitude direction be lat1;

[0158]

[0159] wherein, is the Earth's flattening;

[0160] Repeat adding child nodes until the latitude of the new child node is greater than or equal to lat max , obtaining the longitude and latitude set of the child nodes;

[0161] Step 2.3: Remove the child nodes located outside the area target to obtain the area child node set:

[0162] Step 2.3.1: According to the longitude and latitude set of the child nodes obtained in step 2.2, traverse each child node in the longitude and latitude set of the child nodes to obtain the longitude and latitude position of each child node;

[0163] Let any one of the child nodes in the longitude and latitude set of the child nodes be node k ;

[0164] Step 2.3.2: Obtain the number of intersection points of the right ray of the child node and the boundary line of the area target:

[0165] For each boundary line of the area target, the two vertices of the boundary line are denoted as point i and point j ;

[0166] For the child node whose latitude is between the latitudes of the two vertices of the boundary line, if the child node is on the left side of the boundary line composed of the two vertices, it is considered that the right ray of the child node intersects with the boundary line once; wherein:

[0167] If the condition is met, it is considered that the latitude of the child node node k is between the latitudes of the two vertices of the boundary line;

[0168] If the conditions are met Then the child node is considered k If it is to the left of the boundary line, it is considered a child node. k A ray to the right and two vertices (points) i and point j The boundary lines they form have one intersection point;

[0169] Step 2.3.3: Based on the number of intersections obtained in Step 2.3.2, determine whether the child node is within the target area;

[0170] Iterate through each child node in the set of latitude and longitude coordinates of the child nodes:

[0171] If any child node k If the number of intersections between the rightward ray and the boundary line of the target area is even, then the child node is... k Outside of regional objectives;

[0172] Remove all child nodes outside the target area from the child node latitude and longitude set to obtain the set of child nodes in the region, denoted as Nodes.

[0173] In this embodiment, the major semi-axis of the Earth is the equatorial radius, and the minor semi-axis of the Earth is the polar radius.

[0174] In this embodiment, the longitude set of the child nodes includes multiple child nodes; the multiple child nodes are at the same latitude, and the latitude value is the minimum latitude value; the longitude values ​​of the multiple child nodes are between the minimum longitude value and the maximum longitude value (including the minimum longitude value and the maximum longitude value).

[0175] In this embodiment, the effect of using discretized child nodes to cover the target area is as follows: Figure 2 As shown. From Figure 2 As can be seen, the target area is an irregular polygon. First, child nodes are added in the longitude and latitude directions to cover the entire target area. Then, the child nodes outside the target area are deleted, and finally, a set of child nodes that match the shape of the target area is obtained.

[0176] In this embodiment, the child node k The latitude lies between the latitudes of the two vertices of the boundary line, including child nodes. k The situation on the border line.

[0177] In this embodiment, according to the characteristics of the satellite earth observation payload, the load field range and the regional target shape are comprehensively referenced, and the discrete processing of the to-be-observed regional target is adaptively performed. The region is divided into a plurality of regional sub-nodes which can be observed by the satellite payload in a single observation, so as to reduce the complexity of the regional visibility and coverage operation.

[0178] In addition, in an embodiment, the step of calculating the minimum observation elevation angle, the minimum observation angle of the satellite to each sub-node in the regional target in each orbit and the target sub-node with observation opportunity in each orbit, comprises the following steps:

[0179] Step 3.1: setting the start and end time of the observation task scene performed on the regional target;

[0180] Step 3.2: calculating the orbit per second of the satellite in the observation task scene using the orbit recursion algorithm;

[0181] Let the orbit per second of the satellite be LLA={lla0, lla1, …, lla j , …}; wherein lla j is the latitude, longitude and altitude data sample of the satellite at the jth second of the orbit;

[0182] lla j ={lat j ′, lon j ′, alt j ′};

[0183] Wherein lat j ′ represents the latitude value of lla j , lon j ′ represents the longitude value of lla j , and alt j ′ represents the altitude value of lla j ;

[0184] Step 3.3: orbit division:

[0185] Traverse the orbit per second of the satellite LLA:

[0186] When (lat′ j -lat′0)·(lat′ j+1 -lat′0)<0, record the position represented by lla j as the end of the current orbit, and record the position represented by lla j+1 as the start of the next orbit, and obtain the orbit per orbit of the satellite;

[0187] Step 3.4: Calculate the overall geometric visible time window of the satellite to all the sub-nodes in the regional target in each orbit:

[0188] Step 3.4.1: Let the altitude value of the satellite on the orbit be alt and the radius of the earth be R in each orbit e Then the distance from the satellite to the center of the earth is R Sat = R e + alt;

[0189] Step 3.4.2: Calculate the maximum range of the satellite to any sub-node in the regional target on the earth surface to obtain the geometric visibility, and the opening angle is η:

[0190]

[0191] Then the central angle of the satellite to any sub-node in the regional target is

[0192] Step 3.4.3: Calculate the overall geometric visible time window of the satellite to all the sub-nodes in the regional target by using the binary search method:

[0193] In each orbit, each orbit is divided into an initial step The binary search method is used to calculate whether the satellite is in the geometric visible time window based on the opening angle η, and the time data of the starting position and the ending position of the geometric visible time window of the satellite to any sub-node in the regional target are obtained; wherein, represents the upward rounding;

[0194] In each orbit, the time data of the starting position and the ending position of the geometric visible time window of the satellite to each sub-node in the regional target are combined, and the earliest starting time and the latest ending time are selected to obtain the overall geometric visible time window of the satellite to all the sub-nodes in the regional target, which is called the overall geometric visible time window;

[0195] Step 3.5: Based on the overall geometric visible time window of the satellite to all the sub-nodes in the regional target, calculate the minimum observation angle of the satellite to each sub-node in the regional target in each orbit:

[0196] Step 3.5.1: Calculate the expression of the horizon line;

[0197] In each orbit of the satellite, the two horizon points of longitude and latitude of the starting position and the ending position in the overall geometric visible time window are obtained;

[0198] According to the two horizon points of longitude and latitude, the expression of the horizon line is obtained as:

[0199]

[0200] wherein, The longitude of the nadir point at the beginning of the overall geometrically visible time window; The latitude of the nadir point at the beginning of the overall geometrically visible time window; The longitude of the nadir point at the end of the overall geometrically visible time window; The latitude of the nadir point at the end of the overall geometrically visible time window;

[0201] Step 3.5.2: Calculate the position of the foot of the perpendicular line drawn from each child node in the set of child nodes in the region to the lower star line:

[0202] Solve the following two equations simultaneously:

[0203]

[0204] Based on the result of the joint equation, any child node can be obtained. k Position of the foot of the perpendicular line drawn from the lower star:

[0205]

[0206] The sub-star point position corresponding to the perpendicular position is any child node. k The corresponding nearest sub-satellite point position is used to obtain the satellite orbit position lla corresponding to the perpendicular position. s ;

[0207] Step 3.5.3: Obtain the minimum observation angle for each child node within the target area:

[0208] The satellite orbit position corresponding to the vertical foot position is 1a s Representation in Earth-centered, Earth-fixed coordinate system: ecef(lla) s );

[0209] any child node k Representation in Earth-centered, Earth-fixed coordinate system: ecef(node) k );

[0210] Then the satellite can monitor any child node within the target area. k The minimum observation angle is ξ k :

[0211]

[0212] Step 3.6: Based on the overall geometric visibility time window of the satellite for all sub-nodes within the regional target area, calculate the target sub-nodes with observation opportunities in each orbit, and the payload visibility time window of the satellite for the regional target area:

[0213] Step 3.6.1: Obtain the time period between the earliest start time and the latest end time of the overall geometric visible time window, and obtain the satellite's orbit per-second latitude, longitude and altitude data within the time period according to the orbit extrapolation data

[0214] Step 3.6.2: Traverse the satellite's minimum observation angle ξ of any sub-node node in the regional target in each orbit k k :

[0215] If ξ k ≤ α + ω, any sub-node node is a target sub-node; the satellite has an observation opportunity for the target sub-node; k

[0216] Wherein, ω is the maximum maneuvering yaw angle of the satellite; α is the half opening angle, for a conical field of view load, α = α1, for a rectangular field of view load, α = α2;

[0217] Step 3.6.3: Obtain the satellite orbit position lla s ' corresponding to the target sub-node; the scene time when the satellite has an observation opportunity for the target sub-node is determined according to the satellite orbit position lla s ' and the latitude, longitude and altitude data;

[0218] Step 3.6.4: Select the earliest time and the latest time from the scene time when the satellite has an observation opportunity for all target sub-nodes in each orbit, and the time window between the two is the load visible time window of the satellite for the regional target in each orbit.

[0219] In this embodiment, for a multi-satellite joint earth observation system formed by a plurality of earth observation satellites, each satellite needs to calculate the corresponding minimum observation angle and load visible time window.

[0220] In this embodiment, the latitude, longitude and altitude data, i.e. position data, includes latitude value, longitude value and altitude value and other information.

[0221] In this embodiment, the geometric visible time window of the satellite for any sub-node in the regional target is as shown in Figure 3 Based on the opening angle η, it is determined whether the satellite is within the geometric visible time window corresponding to any sub-node.

[0222] In this embodiment, for the geometric visible time window, refer to the following literature:

[0223] ​​​E. Zhibo, J. Li, "Fast calculation method of regional target visibility for remote sensing satellites", Journal of Tsinghua University (Science and Technology), Vol. 59, no. 9, doi:10.16511 / j.cnki.qhdxxb.2019.26.020.

[0224] In this embodiment, regarding the binary search method, refer to the following document:

[0225] L. Rabiner, "Combinatorial optimization: Algorithms and complexity," in IEEE Transactions on Acoustics, Speech, and Signal Processing, vol. 32, no. 6, pp. 1258-1259, December 1984, doi: 10.1109 / TASSP.1984.1164450.

[0226] In this embodiment, the time data of the starting position and the ending position of the geometric visible time window of each sub-node in the regional target for the satellite, i.e., the starting time node and the ending time node of the geometric visible time window.

[0227] In this embodiment, the calculation of the time data of the starting position and the ending position of the geometric visible time window of each sub-node in the regional target for the satellite has a precision of 1 second.

[0228] In this embodiment, the time data of the starting position and the ending position of the geometric visible time window of each sub-node in the regional target for the satellite are combined to select the earliest starting time and the latest ending time:

[0229] The time data of the starting position and the ending position of the geometric visible time window of each sub-node in the regional target for the satellite, i.e., the starting time node and the ending time node of the geometric visible time window corresponding to each sub-node;

[0230] Combining these starting time nodes and ending time nodes can select the earliest starting time and the latest ending time of the overall geometric visible time window corresponding to all sub-nodes.

[0231] The earliest starting time of the overall geometric visible time window corresponds to the starting position of the overall geometric visible time window;

[0232] The latest ending time of the overall geometric visible time window corresponds to the ending position of the overall geometric visible time window.

[0233] In this embodiment, taking the cth orbit as an example, the time data of the starting position and the ending position of the (geometric) geometric visibility time window of the satellite pair for the ith sub-node (or target sub-node i) in the regional target is accessed c i The overall geometric visibility time window of the satellite pair for all sub-nodes in the regional target is recorded as Access c .

[0234] In this embodiment, the process of obtaining the minimum observation angle is as shown in Figure 4 .

[0235] In this embodiment, the present application realizes rough calculation of the visible arc segment of the satellite pair for the regional target according to the satellite orbit and the shape of the earth; gives up the traditional traversal judgment method, and realizes rapid calculation of the accurate visibility time window of each satellite pair for the regional sub-node based on the bisection search method for accurate judgment of the starting position of the visibility time window; and obtains the visibility time window result of each satellite pair for the regional target based on the visibility of the regional sub-node.

[0236] In addition, in an embodiment, the sub-node grouping step is to construct a strip interval and group all target sub-nodes according to the minimum observation angle and the target sub-node, including the following steps:

[0237] Step 4.1: Process the minimum observation angle ξ k of the target sub-node corresponding to the observation opportunity of the satellite in each orbit:

[0238] Determine the positional relationship between the target sub-node and the subsatellite line. If the target sub-node is located on the left side of the subsatellite line, the minimum observation angle ξ k takes a negative value, otherwise the value remains unchanged:

[0239]

[0240] Among all the target sub-nodes, let the minimum value of ξ k be ξ min , and the maximum value of ξ k be ξ max .

[0241] Step 4.2: Take the target sub-node corresponding to ξ min as the starting point, 2α as the step size, and the target sub-node corresponding to ξ max as the end point, construct a strip interval, and divide all target sub-nodes into groups according to the imaging side swing angle of the satellite:

[0242] [ξ min , ξ min + 2α], [ξ min + 2α, ξ min+ 2a],..., [, ξ max ].

[0243] The average of the minimum observation angles of the two end points of each group is the imaging side swing angle of each group of satellites.

[0244] In this embodiment, the average of the minimum observation angles of the two end points of each group is the imaging side swing angle of each group of satellites, for example:

[0245] [ξ min ,ξ min The minimum observation angles of the two end points of this group are ξ min and ξ min + 2a, respectively, and the average of ξ min and ξ min + 2a is the imaging side swing angle of this group of satellites.

[0246] [ξ min + 2a,ξ min + 4a] The minimum observation angles of the two end points of this group are ξ min + 2a and ξ min + 4a, respectively, and the average of ξ min + 2a and ξ min + 4a is the imaging side swing angle of this group of satellites.

[0247] In addition, in an embodiment, the merging strip step merges the target sub-nodes into strips according to the grouping of all target sub-nodes, and uses a convex hull algorithm to obtain the vertex positions of the strips and the time window for the satellite to observe each group of strips, including the following steps:

[0248] Step 5.1: Merge each group of target sub-nodes using a convex hull algorithm to obtain the vertex positions of the strips corresponding to each group of target sub-nodes;

[0249] Step 5.2: The load visibility time window of each group of target sub-nodes is used as the time window for the satellite to observe each group of strips.

[0250] Step 5.3: The ratio of the number of target sub-nodes included in each group of strips to the number of all sub-nodes of the regional target is used as the target coverage rate of each group of strips.

[0251] In this embodiment, each group of target sub-nodes is merged using a convex hull algorithm to obtain the vertex positions of the strips, as shown in Figure 5 .

[0252] In this embodiment, the vertex positions of the strips are obtained, i.e., the strips corresponding to each group of target sub-nodes are determined.

[0253] In this embodiment, the convex hull algorithm is a classic problem in computational geometry, and its goal is to find the smallest convex polygon of a geometric shape that can enclose all the original points (i.e., for each set of target child nodes, find a smallest convex polygon as a strip to enclose all the target child nodes).

[0254] For the convex hull algorithm, please refer to the following documents:

[0255] Guan Baosheng, "Computational geometry construction of convex hull of spatial finite point set", Journal of Northwest University (Natural Science Edition), Vol. 3, 1985. 20-26 + 19.

[0256] In this embodiment, the method of representing the observation condition with the minimum observation angle required by the satellite to observe the child node uses angle to represent the relative position relationship of the load observation target, uses the position relationship between the subsatellite line of the satellite and the child node, and obtains the minimum observation angle according to the satellite-geometric geometry to represent the observation posture of the satellite to the target under the minimum maneuvering angle, so as to quickly calculate the load visibility of the target to the satellite.

[0257] In this embodiment, the method of merging the regional child nodes into strips and determining the satellite load working time window is to group and aggregate the observation conditions of the obtained nodes, recombine each child node according to the minimum observation angle and other conditions to become the strip information required by the task planning, and directly determine the observation time window of the strip according to the earliest and latest values of the overpass time of the satellite to each node.

[0258] In an embodiment, an adaptive discretization decomposition device for satellite observation planning of regional targets is provided, and the device comprises the following modules:

[0259] Step length determination module: determine the discretization step length of the regional target according to the observation range of the satellite load;

[0260] Discretization into child node set module: discretize the regional target into a regional child node set based on the discretization step length and the shape of the earth; the regional child node set comprises a plurality of child nodes;

[0261] Minimum observation elevation angle calculation module: calculate the minimum observation angle of the satellite to each child node in the regional target in each orbit and the target child node with observation opportunity in each orbit;

[0262] Child node grouping module: construct a strip interval and group all target child nodes according to the minimum observation angle and the target child node;

[0263] Strip merging module: merge the target child nodes into strips according to the grouping condition of all target child nodes, and calculate the vertex position of the strip and the time window of the satellite observation of each group of strips by using the convex hull algorithm.

[0264] It should be noted that the step length of the region discretization according to the shape of the earth and the load observation range, the determination of the minimum observation angle of the satellite by the target sub-node, and the strip division are the originality of the present application.

[0265] It should be noted that the existing related regional target decomposition (or simplification) algorithm simply discretizes the region into point targets for processing, such as the method described in the Chinese patent document with publication number "CN 111695237 A" and the name "Regional decomposition method and system for satellite region coverage detection simulation". This method simply discretizes a region into multiple point targets for operation. Although this method is simple, it does not consider the impact of discretization on the accuracy of observation calculation: if the interval of the target point is too large, the accuracy will be significantly reduced, and if the interval is too small, more calculation memory will be occupied. In addition, due to the influence of the earth's flattening and the satellite-geometric geometry, the point targets divided by equal distance may not be uniformly distributed in terms of satellite observation angle, which will also cause certain errors. On the other hand, considering the change of the observation width of the agile satellite under different attitudes, using a fixed length to divide the region into strips will cause errors, which is particularly evident when the satellite side swing angle is large.

[0266] The adaptive discretization (regional strip) decomposition method in the present embodiment uses an adaptive discretization method based on the satellite load observation range, and comprehensively considers the satellite load observation range and the shape of the earth to discretize the region target to be observed into a set of regional sub-nodes. The satellite visibility of each sub-node is represented using a vector. The observation angle is used to represent the observation of the satellite to the regional sub-node, which contains the observation attitude information of the satellite and avoids the process of calculating the exact visibility window for each sub-node, making the related calculation simpler. Instead of using the fixed width of the traditional method, the set of regional sub-nodes is integrated according to the satellite observation range and the maneuvering ability to obtain the time window of the satellite observation of each group of strips for selection and reference by the subsequent task planning.

[0267] The above describes the technical solutions provided by the present application in further detail through several specific embodiments, in order to highlight the advantages and benefits of the technical solutions provided by the present application. However, the above several specific embodiments are not used as a limitation of the present application, and any reasonable changes and improvements to the present application, reasonable combinations and equivalent replacements of the embodiments, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for adaptive discretization decomposition of satellite observation planning for regional targets, characterized in that, The method comprises the following steps: A step of determining a step length: determining a discretization step length of a regional target according to an observation range of a satellite payload; A step of discretizing into a set of child nodes: discretizing the regional target into a set of regional child nodes based on the discretization step length and the shape of the earth; the set of regional child nodes comprises a plurality of child nodes; A step of calculating a minimum observation elevation angle: calculating a minimum observation angle of each child node in the regional target by the satellite in each orbit pass and a target child node for which there is an observation opportunity by the satellite in each orbit pass; A step of grouping child nodes: constructing a strip interval and grouping all target child nodes according to the minimum observation angle and the target child node; A step of merging strips: merging the target child nodes into strips according to the grouping of all target child nodes, and using a convex hull algorithm to obtain the vertex positions of the strips and the time window for observing each group of strips by the satellite; The step of determining the step length comprises the following steps: Step 1.1: determining the observation range of the satellite payload: Classify the earth observation satellite according to the observation range of the payload into a conical field of view and a rectangular field of view; wherein the conical field of view has the same field of view angle in each direction, and the rectangular field of view has different angles in two perpendicular directions; Let the minimum height of the satellite orbit be , the half opening angle of the conical field of view of the load be , the half opening angle of the load perpendicular to the forward direction of the satellite of the rectangular field of view be , and the half opening angle of the load parallel to the forward direction of the satellite of the rectangular field of view be ; The circular radius of the ground projection of the load of the conical field of view is The rectangular side length of the ground projection of the load of the rectangular field of view is and ; wherein , , ; Step 1.2: calculating the discretization step length of the regional target: The discretization step of the region target is set as which is determined by the minimum observation range of the satellite payload; For a conical field of view of the load, ; For a rectangular field of view, the load, .

2. The method of claim 1, wherein, The step of discretizing into a set of child nodes comprises the following steps: Step 2.1: determining the position of each vertex of the regional target: determining a region target of the required observation a vertex, the vertex position being expressed in latitude and longitude, denoted by wherein denotes the latitude, denotes the longitude; the maximum value of the latitude of the vertex is , the minimum value of the latitude of the vertex is , the maximum value of the longitude of the vertex is , and the minimum value of the longitude of the vertex is ; Step 2.2: covering the regional target with child nodes: Step 2.2.1: calculating the longitude set of the child nodes according to the latitude and longitude range of the vertices of the regional target in step 2.1: from the vertex corresponding to the longitude minimum and the latitude minimum beginning at adding child nodes one by one in the direction of the same latitude and higher longitude with a step of 1; in the process of adding each child node: Let the longitude of the starting point be , and the latitude be , which corresponds to a radius of the earth's latitude circle of : wherein is the length of the semi-major axis of the Earth; is the length of the semi-minor axis of the Earth; The longitude of the new child node obtained by moving in the direction of the same latitude and high longitude is : repeating adding the child node until the longitude of the new child node is greater than or equal to , obtaining the longitude set of the child node; Step 2.2.2: based on the longitude set of the child nodes obtained in step 2.2.1, diffusing the child nodes to the high latitude direction based on the longitude set of the child nodes obtained in step 2.1, so that the child nodes cover the regional target: Starting with each child node in the longitude set, add child nodes to the same longitude and high latitude direction one by one; in each addition of a child node: Let the longitude of the starting point be , the latitude be , and the latitude of the new child node obtained by moving in the direction of the same longitude and high latitude be ; wherein is the oblateness of the Earth; repeating adding the child node until the latitude of the new child node is greater than or equal to , obtaining the longitude and latitude set of the child node; Step 2.3: removing child nodes located outside the regional target to obtain a set of regional child nodes: Step 2.3.1: according to the latitude and longitude set of the child nodes obtained in step 2.2, traverse each child node in the latitude and longitude set of the child nodes to obtain the latitude and longitude position of each child node; Let any one of the child nodes in the set of latitude and longitude of the child nodes be ; Step 2.3.2: obtaining the number of intersection points of the right ray of the child node with the boundary line of the regional target: For each boundary line of the area target, record the two vertices of the boundary line as and ; For a child node whose latitude is between the latitudes of the two vertices of the boundary line, if the child node is on the left side of the boundary line composed of the two vertices, it is considered that the right ray of the child node intersects the boundary line at one point; wherein: If the condition is met, then the latitude of the child node is considered to be between the latitudes of the two vertices of the boundary line; If the condition is satisfied, the child node is considered to be on the left side of the boundary line , and the ray to the right of the child node has one intersection point with the boundary line composed of two vertices and Step 2.3.3: determining whether the child node is within the regional target according to the number of intersection points obtained in step 2.3.2; Traverse each child node in the latitude and longitude set of the child nodes: If any one of the sub-nodes If the number of intersection points of the right ray and the region target boundary line is even, the sub-node Outside the region target All the child nodes outside the regional target are deleted from the longitude and latitude set of the child nodes to obtain a regional child node set, denoted as .

3. The method of claim 2, wherein, The step of calculating the minimum observation elevation angle comprises the following steps: Step 3.1: setting the start and end times of the observation task scenario for the regional target; Step 3.2: calculating the orbit data of the satellite every second in the observation task scenario using an orbit recursion algorithm; Let the satellite's orbital latitude and longitude data per second be ; wherein, is the satellite's latitude and longitude data sample at the jthsecond of the orbit. ； wherein represents the latitude value of represents the longitude value of represents the altitude value of Step 3.3: orbit pass division: Traversing the satellite's orbital ephemeris data every second for longitude, latitude, and altitude : when At that time, The indicated position is marked as the end of the current cycle. The indicated position is marked as the start of the next orbit, and the latitude, longitude, and altitude data of the satellite's orbit for each orbit are obtained; Step 3.4: Calculate the overall geometric visible time window of the satellite to all the sub-nodes in the region target in each orbit; Step 3.4.1: Let the height of the satellite above the earth's surface in each revolution be , the radius of the earth be , then the distance from the satellite to the center of the earth is ; Step 3.4.2: Calculate the maximum range of the satellite's geometric visibility to any sub-node within the area target on the Earth's surface is the angle of the sector : ； The geocentric angle of the satellite to any sub-node in the regional target is ; Step 3.4.3: Calculate the overall geometric visible time window of the satellite to all the sub-nodes in the region target in each orbit by using binary search method; traversing each round, each round is divided into initial steps The bisecting search method is calculated based on the opening angle Determine whether the satellite is in the geometric visibility time window, obtain the starting position and ending position of the satellite to any sub-node in the regional target The time data of the geometric visibility time window; wherein, Indicates rounding up; In each orbit, combine the time data of the start position and the end position of the geometric visible time window of the satellite to each sub-node in the region target, select the earliest start time and the latest end time, and obtain the overall geometric visible time window of the satellite to all the sub-nodes in the region target, which is called the overall geometric visible time window; Step 3.5: Calculate the minimum observation angle of the satellite to each sub-node in the region target in each orbit based on the overall geometric visible time window of the satellite to all the sub-nodes in the region target; Step 3.5.1: Calculate the expression of the nadir line; In each orbit of the satellite, obtain the two nadir points of the start position and the end position of the overall geometric visible time window; According to the two nadir points, the expression of the nadir line is obtained as: wherein, is the sub-satellite point longitude of the start location in the overall geometry visibility time window; is the sub-satellite point latitude of the start location in the overall geometry visibility time window; is the sub-satellite point longitude of the end location in the overall geometry visibility time window; is the sub-satellite point latitude of the end location in the overall geometry visibility time window; Step 3.5.2: Calculate the foot position of the perpendicular line from each sub-node in the region sub-node set to the nadir line: Solve the following two equations simultaneously: According to the result of the simultaneous equation, any sub node is obtained The foot position of the perpendicular line to the star down line: The foot position corresponds to the sub node position of any sub node The corresponding nearest foot position, and then the satellite orbit position corresponding to the foot position ; Step 3.5.3: Obtain the minimum observation angle of each sub-node in the region target: the satellite orbit position corresponding to the foot point position is converted into a representation in the geocentric geodetic coordinate system: ; Converts any child node to the representation in the geocentric geodetic coordinate system: ; The minimum observation angle of the satellite to any sub-node in the regional target is : : ； Step 3.6: Calculate the target sub-node with observation opportunity and the payload visible time window of the satellite to the region target in each orbit based on the overall geometric visible time window of the satellite to all the sub-nodes in the region target: Step 3.6.1: Obtain the time period between the earliest start time and the latest end time of the overall geometric visibility time window, and obtain the satellite's orbital longitude, latitude, and altitude data per second within the time period according to the orbital extrapolation data ; Step 3.6.2: Traversing the satellite's minimum observation angle for any sub-node within the regional target in each orbit pass :​ If , then any child node corresponding to the target child node; the satellite has an observation opportunity with the target child node; wherein is the largest maneuvering yaw angle of the satellite; is the half angle of view, for a conical field of view, , for a rectangular field of view, ; Step 3.6.3: Obtain the satellite orbit position corresponding to the target child node ; reference latitude and longitude data , satellite orbit position Determine the scene time when the satellite has an observation opportunity for the target child node Step 3.6.4: Select the earliest time and the latest time from the scene time when the satellite has observation opportunity to all the target sub-nodes in each orbit, and the time window between the two is the payload visible time window of the satellite to the region target in each orbit.

4. The method of claim 3, wherein, The sub-node grouping step includes the following steps: Step 4.1: The minimum observation angle corresponding to the target sub-node pair for which the satellite has an observation opportunity in each orbit Process: If the target child node is located on the left side of the line-of-sight, the minimum observation angle is taken as a negative value, otherwise the value remains unchanged. If the target child node is located on the left side of the line-of-sight, the minimum observation angle is taken as a negative value, otherwise the value remains unchanged. ； Among all the target child nodes, let the minimum value of , the maximum value of ; Step 4.2: with the corresponding target child node as the start point, a step size, and the corresponding target child node as the end point, a strip interval is constructed, and all target child nodes are divided into groups according to the satellite imaging side swing angle: ； The average of the minimum observation angles of the two endpoints of each group is the imaging side-swing angle of each group of satellites.

5. The method of claim 4, wherein, The merging strip step includes the following steps: Step 5.1: Merge each group of target sub-nodes using the convex hull algorithm to obtain the vertex position of the strip corresponding to each group of target sub-nodes; Step 5.2: Take the payload visible time window of each group of target sub-nodes as the time window for the satellite to observe each group of strips; Step 5.3: Take the ratio of the number of target sub-nodes included in each group of strips to the number of all sub-nodes in the region target as the target coverage rate of each group of strips.

6. An apparatus for adaptive discretization decomposition for satellite observation of regional targets, characterized in that, The device includes the following modules: Step length determination module: determine the discretization step length of the region target according to the observation range of the satellite payload; Discretization into sub-node set module: discretize the region target into a region sub-node set based on the discretization step length and the shape of the earth; the region sub-node set includes a plurality of sub-nodes; Minimum observation elevation angle calculation module: calculate the minimum observation angle of the satellite to each sub-node in the region target in each orbit and the target sub-node with observation opportunity in each orbit; Sub-node grouping module: construct a strip interval and group all target sub-nodes according to the minimum observation angle and the target sub-node; The merging strip module merges the target sub-nodes into strips according to the grouping of all target sub-nodes, and uses a convex hull algorithm to obtain the vertex position of the strip and the time window of the satellite for observing each group of strips; The step length determination module is configured to perform the following steps: Step 1.1: determining the observation range of the satellite payload: The earth observation satellite is classified according to the observation range of the payload, and is divided into conical field of view and rectangular field of view payloads; wherein the conical field of view payload has the same field of view angle in each direction, and the rectangular field of view payload has different field of view angles in two perpendicular directions; The minimum height of the satellite orbit is , the half opening angle of the load with a conical field of view is , the half opening angle of the load with a rectangular field of view perpendicular to the forward direction of the satellite is , and the half opening angle of the load with a rectangular field of view parallel to the forward direction of the satellite is ; The circular radius of the ground projection of the load of the conical field of view is , and the rectangular side length of the ground projection of the load of the rectangular field of view is and ; wherein, , , ; Step 1.2: calculating the discretization step length of the regional target: The discretization step of the region target is set as which is determined by the minimum observation range of the satellite payload; For a conical field of view of the load, ; For rectangular field of view of load, .

7. A computer system comprising: A processor and a memory, characterized in that the memory is used to store executable instructions of the processor, and the processor is configured to execute the adaptive discretization decomposition method for satellite observation planning of regional targets according to any one of claims 1-5 by executing the executable instructions.

8. A computer storage medium, characterized in that, The storage medium stores a computer program, and the computer program runs to execute the adaptive discretization decomposition method for satellite observation planning of regional targets according to any one of claims 1-5.

9. A computer program product comprising computer programs / instructions, characterized in that, The computer program / instructions are executed by the processor to realize the steps of the adaptive discretization decomposition method for satellite observation planning of regional targets according to any one of claims 1-5.

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