CN110705888B

CN110705888B - Partitioned satellite task planning method for minimum-cost area target coverage

Info

Publication number: CN110705888B
Application number: CN201910957780.1A
Authority: CN
Inventors: 夏维; 高天旸; 胡笑旋; 王执龙; 靳鹏; 罗贺; 伍艺; 朱外明
Original assignee: Hefei University of Technology
Current assignee: Hefei University of Technology
Priority date: 2019-10-10
Filing date: 2019-10-10
Publication date: 2022-03-15
Anticipated expiration: 2039-10-10
Also published as: CN110705888A

Abstract

The invention discloses a partitioned satellite task planning method for target coverage in a minimum cost area, which comprises the following steps: 1. partitioning a rectangular region to be observed; 2. and allocating observation resources to different partitions and selecting coverage modes for the different partitions so as to maximize the coverage area corresponding to the formed coverage scheme as much as possible, and allocating the observation resources to the different partitions and selecting the coverage modes for the different partitions so as to minimize the coverage cost corresponding to the formed coverage scheme as much as possible. The invention can obtain a satisfactory scheme for completely covering the regional targets with the lowest cost by using proper computing resources, and achieve the balance between the computing resource consumption and the optimality of the solution, thereby fully utilizing satellite resources in the actual environment and carrying out economic and effective coverage search on important regional targets.

Description

Partitioned satellite task planning method for minimum-cost area target coverage

Technical Field

The invention belongs to the field of target task planning of earth observation satellite regions, and particularly relates to a partition satellite task planning method for minimum-cost region target coverage.

Background

An Earth Observation Satellite (EOS), or an imaging Satellite (hereinafter referred to as "Satellite"), has one of its main functions of observing the land, the sea, the atmosphere, etc. through a Satellite-borne sensor (such as a visible light camera and a multispectral camera). The observation requirements are provided by users from various fields and departments, the requirements are summarized at a ground control center of the satellite, the control center comprehensively formulates an imaging coverage plan of each satellite according to the observation requirements by combining the service condition of satellite resources, measurement and control instructions are generated and are uploaded to the satellite through a ground measurement and control station, the satellite performs corresponding actions after receiving the instructions, imaging is performed on a specified area, formed image data are temporarily stored on a satellite-borne hard disk, and when the satellite can communicate with the ground station, the image data are downloaded to the ground station. In the process, a link of making a satellite imaging plan by the ground control center is called as satellite mission planning and is one of key links in the whole satellite use management process.

In a traditional satellite use mode, a satellite independently makes a plan and independently executes an imaging task, and cooperative observation is not carried out between the satellite and the satellite. With the increase of the number of satellites, imaging observation on the ground by using multiple satellites in cooperation has become possible, and the real requirement of multi-satellite cooperation regional imaging exists.

The satellite can only shoot a strip area with limited length and width in one transit, and if the area to be observed is large, the whole area is difficult to be completely observed in one transit of the satellite. If the user urgently needs the image data of the area, multiple satellite transit opportunities can be used for collaborative imaging. Since the sub-satellite point trajectories for each satellite are not necessarily parallel, overlap between the imaged swaths may result. If the arrangement is not reasonable, then a large amount of overlap between the bands may be caused, so that some regions are repeatedly observed and some regions are not observed, which is very unfavorable for reasonable utilization of resources. In order to better utilize the existing satellite coverage resources, a reasonable plan should be made, and the behavior actions (mainly including the on-off time and the side-sway angle) of each transit of the satellite are arranged, so that the effect of the cooperative observation of multiple coverage opportunities of multiple satellites is as good as possible. The method is a typical operational optimization problem, and has urgent practical requirements. The following application scenarios also exist in this type of optimization problem: in a certain time interval, the user department needs the complete image data of a certain larger area, and the number of the available satellites is sufficient, so that the user department can completely shoot the area completely. In this case, in order to save resources as much as possible, it is desirable to make a coverage scheme so that its coverage cost is as small as possible. We call this problem the minimum coverage cost problem in the case of sufficient coverage resources. When a general regional target planning method is used for a large region to be observed in the problem, a large amount of computing resources may be consumed due to the fact that the problem scale is too large and the problem complexity is too high. This is not conducive to the use of the method in a practical engineering environment.

Disclosure of Invention

The invention aims to solve the defects of the prior art and provides a partitioned satellite task planning method with minimum cost for regional target coverage, so that a satisfactory scheme for completely covering regional targets with minimum cost can be obtained by using proper computing resources, and the balance between computing resource consumption and solution optimality is achieved, so that satellite resources can be fully utilized in an actual environment, and economic and effective coverage search is performed on important regional targets.

The invention adopts the following technical scheme for solving the technical problems:

the invention relates to a partitioned satellite task planning method covered by a minimum-cost area target, which is characterized by being applied to a coverage mode planning which completely covers a rectangular area R to be observed by using a sufficient coverage machine set S and ensures that the coverage cost is as small as possible, wherein each coverage opportunity S belongs to S and has own attribute, and the method comprises the following steps: orbit of points under the satellite o_sSatellite ground clearance h_sMaximum boot time m_sAnd m is_sMaximum length r corresponding to one coverage pattern_sMaximum side-swinging angle v_sAngle of view w of camera_s；

The coverage mode c is a rectangular strip formed by satellite shooting and is determined by selecting a certain sidesway angle and on-off time by a coverage opportunity, the coverage cost of the coverage opportunity is in direct proportion to the length of the coverage mode selected by the coverage opportunity, and the proportionality coefficient is

Taking any vertex of the rectangular region R to be observed as an origin o, and taking two edges adjacent to the origin as an x axis and a y axis respectively, so as to establish a coordinate system o-xy; the coordinates of four vertexes of the rectangular region R to be observed are respectively marked as an upper left vertex LU (R), a lower left vertex LD (R), an upper right vertex RU (R) and a lower right vertex RD (R); the partition satellite task planning method is carried out according to the following steps:

step 1: partitioning the rectangular region R to be observed;

step 1.1: set the length L of each partition_pAnd width W_p；

Step 1.2: calculating the length L of the rectangular region R to be observed according to the coordinates of the four vertexes of the rectangular region R to be observed_RAnd width W_R；

Step 1.3: by L_RInteger division L_pGet the long number of segments D of a partition_LAnd remainder R_LIf there is a remainder

Then D will be_L+1 assignment to D_L(ii) a By W_RInteger division of W_pObtaining the number of partitioned wide segments D_WAnd remainder R_WIf there is a remainder

Then D will be_W+1 assignment to D_W；

Step 1.4: by L_RDivided by D_LGet the length L of the final partition_fBy W_RDivided by D_WObtaining the width W of the final partition_f；

Step 1.5: according to the length L of the final partition_fAnd width W_fCarrying out average partition on the rectangular region R to be observed so as to obtain four vertex coordinates of each partition;

step 1.6: obtaining a set N of partitions, and the total number of the partitions is | N | ═ D_L×D_W；

Step 2: allocating observation resources to different partitions and selecting a coverage mode for the observation resources so as to minimize the coverage cost corresponding to the formed coverage scheme as much as possible;

step 2.1: randomly assigning coverage opportunities to partitions to form an initial current assignment scheme

Wherein, y_sRepresents the partition to which the coverage opportunity s is assigned;

step 2.2: computing a set of preferred coverage patterns C under the current allocation scheme Y^*(Y) corresponding overlay cost P (Y);

step 2.3: setting a maximum number of iterations

And initial annealing temperature T₁Making the iteration number k of the current outer loop equal to 1;

step 2.4: if it is not

Step 2.9 is switched to, otherwise step 2.5 is executed;

step 2.5: randomly selecting a coverage opportunity

And based on coverage opportunities

Constructing a plurality of neighbor distribution schemes of a current distribution scheme Y;

step 2.6: respectively calculating the coverage cost corresponding to the better coverage mode set under each neighbor allocation scheme, and selecting one with the minimum coverage cost as the optimal neighbor allocation scheme

Step 2.7: comparative optimal neighbor allocation scheme

Cost of coverage with current allocation scheme Y, if

The optimal neighbor allocation scheme will be used

Assigning a value to the current distribution scheme Y and then directly executing the step 2.8, otherwise, executing the step 2.7.1-the step 2.7.2 and then executing the step 2.8;

step 2.7.1: calculating inferior solution acceptance rate of kth iteration

Step 2.7.2: the kth secondary generation of a random number r of value 0 to 1_kIf r is_k≤p_kThen the optimal neighbor allocation scheme is used

Assigning a value to the current distribution scheme Y;

step 2.8: assigning k +1 to k, updating annealing temperature T_k＝T_k-1X lambda is the cooling coefficient, a fixed value smaller than 1 and larger than 0 is taken, and the step 2.4 is carried out;

step 2.9: outputting the current distribution scheme Y and the preferred coverage mode set C selected by each coverage opportunity in the current distribution scheme^*(Y) and its corresponding coverage cost P (Y).

The partition satellite task planning method is characterized in that the step 1.5 is carried out according to the following processes:

step 1.5.1: let i equal to 1, and take the coordinate lu (R) at the upper left corner of the rectangular region R to be observed as the ith partition n_iCoordinates LU (n) of the upper left corner of_i)；

Step 1.5.2: dividing the ith into n_iCoordinates LU (n) of the upper left corner of_i) Is added with L_fGet its right upper corner coordinates RU (n)_i) Let us coordinate LU (n) in the upper left corner_i) Is added with W_fTo obtain its leftLower angular coordinate LD (n)_i) Then, the coordinate RU (n) at the upper right corner_i) Is added with W_fObtain its lower right coordinate RD (n)_i)；

Step 1.5.3: if the ith partition n_iLower right corner coordinate RD (n)_i) Equal to the lower right corner coordinate rd (R) of the rectangular region R to be observed, go to step 1.5.6, otherwise go to step 1.5.4;

step 1.5.4: if the ith partition n_iRU (n) of the upper right corner_i) The abscissa value of the rectangular region R is equal to the abscissa value of the upper right-hand coordinate RU (R) of the rectangular region R to be observed, then let

As the i +1 th partition n_i+1Coordinates LU (n) of the upper left corner of_i+1) Otherwise, let the ith partition n_iRU (n) of the upper right corner_i) As the i +1 th partition n_i+1Coordinates LU (n) of the upper left corner of_i+1)；

Step 1.5.5: assigning i +1 to i, and then turning to step 1.5.2 for constructing four-vertex coordinates of the next partition;

step 1.5.6: and finishing the partition, and outputting the four-vertex coordinates of each partition.

The step 2.5 is carried out according to the following processes:

step 2.5.1: order partition set

Representing an opportunity to remove coverage in a set of partitions N

The iteration number m of the current inner loop is made to be 0 in the set formed after the distributed partitions;

step 2.5.2: if it is not

If the value is null, turning to the step 2.5.4, otherwise, assigning m +1 to m, and executing the step 2.5.3;

step 2.5.3: overlay machine to be selected in current allocation scheme YWill be provided with

Randomly assigning to partition sets

Is a partition of

Thereby obtaining a neighbor allocation scheme

To be partitioned

From a set of partitions

Removing, and turning to the step 2.5.2;

step 2.5.4: outputting all resulting neighbor allocation schemes

In said step 2.2 and step 2.6, the calculation of the set of preferred coverage modes and corresponding coverage costs for each coverage opportunity selection given an allocation scheme is performed as follows:

step a: taking each different partition and the set of coverage opportunities distributed to the different partitions as input, constructing a grid and calculating local better coverage schemes and corresponding coverage costs of the different partitions by using a heuristic algorithm;

step a.1: dividing the ith into n_iDividing the cell into a plurality of square cells with the same size to obtain a cell set J_i；

Step a.2: according to the divided cell set J_iIs assigned to the ith partition n_iCovering opportunity set S_iGenerating basic coverage patterns and composing a total set C of its optional coverage patterns_i；

The basic coverage mode refers to: the following three cells are present inside:

the four vertexes are all in the area covered by the covering mode;

one of the cells has a vertex positioned on the left boundary of the coverage mode and is named as a left cell, the other cell has a vertex positioned on the upper boundary of the coverage mode and is named as an upper cell, the last cell has a vertex positioned on the lower boundary of the coverage mode and is named as a lower cell, and the left cell, the upper cell and the lower cell can be overlapped;

step a.3: with the ith partition n_iDivided set of cells J_iAnd optional coverage mode set C for each coverage opportunity_iSelecting the coverage mode of each coverage opportunity by a heuristic algorithm for input, thereby obtaining a better coverage mode set

And simultaneously derive its coverage cost P_i；

Step b: overlay scheme for all partitions

Combining to obtain a coverage scheme C of the total R of the rectangular region to be observed^*Coverage cost { P) corresponding to coverage schemes of all partitions_iThe sum of i | 1,2, …, | N | } yields the coverage cost P of the whole rectangular area R to be observed.

In the step a.2, generating a basic coverage mode for the coverage opportunity set according to the cell set, and forming a total set of the selectable coverage modes according to the cell set are performed according to the following steps:

step a.2.1: if it is not

Go to step a.2.4, otherwise execute step a.2.2;

step a.2.2: selecting one of the covering opportunities S E S_iDepending on the type of coverage opportunity s, makeConstruction of a set J of cells for a coverage opportunity s in a corresponding manner_iBasic coverage pattern set C_s：

Step a.2.2.1: from the subsatellite point trajectory o of the coverage opportunity s_sJudging the type of the covering opportunity s, wherein the type of the covering opportunity s is divided into a right downward inclined type and a left downward inclined type;

step a.2.2.2: order set

Step a.2.2.3: from set of cells J_iMiddle screening subset J_sAnd subset J_sEach cell in (a) may be the left cell of the longest basic coverage pattern covering opportunity s;

step a.2.2.4: if it is not

Go to step a.2.2.13, otherwise, select J_sStep a.2.2.5 is performed after one cell p;

step a.2.2.5: from set of cells J, according to cell p_iMiddle screening out cell subset

And when p is taken as the left cell

Each cell in the set can be used as an upper cell and forms a basic coverage mode of a coverage opportunity s together with p;

step a.2.2.6: if it is not

Go to step a.2.2.12, otherwise, choose

Step a.2.2.7 is performed after one cell q;

step a.2.2.7: from set of cells J, based on cells p and q_iMiddle screening out cell subset

And when p is the left cell and q is the upper cell, the subset of cells

Each cell in the set can be used as a lower cell, and the lower cell and p and q together form a basic coverage mode of a coverage opportunity s;

step a.2.2.8: if it is not

Go to step a.2.2.11, otherwise, choose

Step a.2.2.9 is performed after one cell b;

step a.2.2.9: constructing a basic coverage c belonging to a coverage opportunity s based on cells p, q and b_s(p,q,b)；

Step a.2.2.10: c is to_s(p, q, b) addition of C_sUnit cell b from

Removing, and turning to the step a.2.2.8;

step a.2.2.11: cell q is selected from

Removing, and turning to the step a.2.2.6;

step a.2.2.12: cell p from J_sRemoving, and turning to the step a.2.2.4;

step a.2.2.13: output overlay mode set C_s；

Step a.2.3: will cover the opportunity S from S_iRemoving, namely turning to the step a.2.1;

step a.2.4: order to

Output overrideMode set C_i。

The step a.2.2.3 is carried out according to the following process:

step a.2.2.3.1: order to

Step a.2.2.3.2: traverse set J_iCalculating the camera yaw angle of the coverage opportunity s when each cell u is taken as the left cell of the coverage pattern

Wherein, if the covering chance is a right lower corner inclined type, then

The lower left corner vertex LD (u) of cell u and the sub-satellite point locus o covering the opportunity s_sIf the covering opportunity is of a downward left-inclined type, the distance therebetween is set to be smaller

The top left vertex LU (u) of cell u and the Sum-satellite point trajectory o of coverage opportunity s_sIf σ is greater than_s(u)|≤v_sAdd cell u to the left cell subset J_s。

The step a.2.2.5 is carried out according to the following process: step a.2.2.5.1: order to

Step a.2.2.5.2: calculating the stripe width η of the overlay mode using equation (1) for cell p as the left cell_s(p)：

Step a.2.2.5.3: traverse set J_iChecking whether one cell t meets the following four conditions, and if all the conditions are met, adding the cell t into the cell

Otherwise, the next cell to check continues:

if the coverage opportunity is of a lower right-angle slope type, the four conditions are:

drawing a straight line L through the top point of the lower left corner of the cell p_p‖o_sLine L 'is drawn through the top-right vertex of t'_t‖o_sThen straight line L_pAnd L'_tThe distance between cannot exceed the width η of the strips_s(p)；

② drawing straight lines L 'by respectively passing top left corners of cells p and t'_p⊥o_sAnd L_t⊥o_sThen L is_tL'_pAbove (1);

drawing straight line through the top point of the lower left corner of the cell t

Then straight line

At L_pRight side of (c);

fourthly, drawing a straight line through the vertex of the lower right corner of the cell p

Then straight line

And L_tMust not exceed the strip length l_s(ii) a Wherein, "|" represents a parallel relationship, and "|" represents a vertical relationship;

if the coverage opportunity is of a lower left corner slope type, the four conditions are:

drawing a straight line L through the top left corner vertex of the cell p_p‖o_sLine L 'is drawn at the bottom right corner vertex of t'_t‖o_sThen straight line L_pAnd L'_tThe distance between cannot exceed the width η of the strips_s(p)；

② respectively passing through the cells pAnd the top right vertex of t is taken as the straight line L'_p⊥o_sAnd L_t⊥o_sThen L is_tL'_pAbove (1);

drawing straight line through top left corner vertex of cell t

Then straight line

At L_pRight side of (c);

fourthly, drawing a straight line through the vertex of the lower left corner of the cell p

Then straight line

And L_tMust not exceed the strip length l_s(ii) a Where "|" represents a parallel relationship, and "|" represents a vertical relationship.

The step a.2.2.7 is carried out according to the following process: step a.2.2.7.1: order to

Step a.2.2.7.2: traverse set J_iChecking whether one cell a meets the following four conditions, and if all the conditions are met, adding the cell a

Otherwise, the next cell to check continues:

drawing a straight line L through the top point of the lower left corner of the cell p_p‖o_sLine L 'through the top-right vertex of a'_a‖o_sThen straight line L_pAnd L'_aThe distance between cannot exceed the width η of the strips_s(p)；

② respectively passing through the cellsp and the top left vertex of a are taken as straight lines L'_p⊥o_sAnd

then

L'_pBelow (1);

drawing straight line through the top point of the lower left corner of the cell a

Then straight line

At L_pRight side of (c);

drawing a straight line L through the vertex of the lower right corner of the cell a_a⊥o_sDrawing a straight line L at the top left corner vertex of the t_t⊥o_sThen straight line L_aAnd L_tMust not exceed the strip length l_s(ii) a Wherein, "|" represents a parallel relationship, and "|" represents a vertical relationship;

drawing a straight line L through the top left corner vertex of the cell p_p‖o_sLine L 'is drawn through the bottom right corner vertex of a'_a‖o_sThen straight line L_pAnd L'_aThe distance between cannot exceed the width η of the strips_s(p)；

② drawing straight lines L 'by respectively passing top points at the upper right corners of the cells p and a'_p⊥o_sAnd

then

L'_pBelow (1);

drawing straight line through top left corner vertex of cell a

Then straight line

At L_pRight side of (c);

drawing a straight line L through the vertex at the lower left corner of the cell a_a⊥o_sDrawing a straight line L at the top right corner vertex of the t_t⊥o_sThen straight line L_aAnd L_tMust not exceed the strip length l_s(ii) a Where "|" represents a parallel relationship, and "|" represents a vertical relationship.

The step a.2.2.9 is carried out according to the following process:

step a.2.2.9.1: if the coverage chance is a lower right angle oblique type, then pass through the lower left corner vertex LD (p) of the cell p and make a straight line L_p‖o_sDrawing a straight line L through the top left vertex LU (q) of cell q_q⊥o_sDrawing a straight line L through the top RD (q) at the lower right corner of the cell b_b⊥o_sIf the coverage chance is of the lower left corner slope type, then go through the upper left corner vertex LU (p) of the cell p and make a straight line L_p‖o_sLine L is drawn through the top right vertex RU (q) of cell q_q⊥o_sDrawing a straight line L through the lower left corner vertex LD (q) of cell b_b⊥o_s；

Step a.2.2.9.2: strip width η of overlay mode when calculating cell p as left cell_s(p)；

Step a.2.2.9.3: make a straight line

So that it satisfies:

①

②

and L_pEqual to η_s(p)；

③

At L_pRight side of (c);

step a.2.2.9.4: with L_p,

L_q,L_bThe four straight lines are used as four sides of the rectangle, the intersection points of the four straight lines are used as four vertexes of the rectangle, and the covering mode c is constructed_s(p,q,b)。

The step a.3 is carried out according to the following process:

step a.3.1: let J_iThe state of all cells in the cell is "uncovered", and the cell is in the "uncovered" state

Step a.3.2: let g be 1;

step a.3.3: if g > | C_iIf not, go to step a.3.5, otherwise, go to step a.3.4, where | C_iI represents a set of optional coverage modes C_iThe number of elements in (1);

step a.3.4: selection C_iAnd from the set of cells J_iSelecting cells which can be completely covered by the g-th coverage mode and have the state of 'uncovered', recording the cells as an effective cell set V (g) and the number of the cells as | V (g) |, and calculating the coverage cost of the g-th coverage mode

Wherein l_gFor the length of the g-th coverage pattern,

calculating the ratio of the effective unit cell number of the coverage mode to the coverage cost for the cost coefficient of the coverage opportunity s' corresponding to the coverage mode g

Assigning g +1 to g, and then turning to the step a.3.3;

step a.3.5: if it is

Or if the states of all the cells are 'covered', the step a.3.8 is carried out, otherwise, the step a.3.6 is carried out;

step a.3.6: selection C_iMedium effective cost ratio maximum covering mode

And as corresponding coverage opportunities s^*Selected coverage mode, and g^*Adding into

In (1), covering the pattern g^*Valid cell set V (g)^*) The states of all the cells in the cell are changed into covered;

step a.3.7: will cover the opportunity s^*Corresponding set of coverage patterns

From the set of optional overlay modes C_iIs removed from C_iScreening out the coverage mode subset C ' with the upper cell or lower cell status as ' covered '_iAnd from C_iRemoving, and turning to the step a.3.2;

step a.3.8: outputting a set of coverage patterns for each coverage opportunity selection

I.e. final coverage scheme, calculation

The sum of the coverage costs of all coverage modes, i.e. the i-th partition n_iCoverage cost P_i。

Compared with the prior art, the invention has the beneficial effects that:

1. the invention adopts the concept of 'divide-and-conquer' to provide a solution strategy based on partitions, namely, a large area to be observed is decomposed into a plurality of small partitions, coverage resources are distributed to the partitions, each partition is separately solved, and a plurality of partitions are combined to form an overall coverage scheme, so that the scale of the problem is reduced, and the difficulty of optimization is reduced. Different coverage resource allocation schemes may result in different overall coverage schemes, and therefore it is proposed to search for an optimal resource allocation scheme using a simulated annealing method.

2. The invention adopts a grid discretization method to process the subarea to be observed, and converts the original problem into the problem of covering each cell, thereby reducing the coupling with the computational geometry; meanwhile, based on the grids, a basic coverage mode of each observation opportunity is constructed to serve as an optional coverage mode set, and a decision variable is converted from a value obtained in a continuous space to a value obtained in a discrete space, so that the calculated amount is reduced.

3. The invention adopts a heuristic algorithm based on dynamic greedy, and rapidly finds a better coverage scheme for each discretized partition by sequentially selecting the coverage mode with the highest cost performance. The heuristic algorithm is a polynomial time algorithm, and when the total number of the coverage modes is within a reasonable range, the solving speed is high, the implementation is easy, the interpretability is strong, and the method is stable and reliable, so that a better feasible solution of the coverage scheme can be quickly and effectively found in the simulated annealing process of the method, and the searching speed of the solution space of the distribution scheme is increased.

Drawings

FIG. 1 is a flow chart of a method for partitioned satellite mission planning with minimum cost area target coverage according to the present invention;

FIG. 2a is a schematic view of the target coverage of a lower left-inclined zone in accordance with the present invention;

FIG. 2b is a schematic diagram of the target coverage of the lower right sloping type zone of the present invention;

FIG. 2c is a schematic diagram of multi-satellite cooperative coverage according to the present invention;

FIG. 3a is a schematic diagram of the formation of a blanket pattern in accordance with the present invention;

FIG. 3b is a diagram illustrating the maximum coverage pattern length according to the present invention;

FIG. 3c is a schematic side view of a satellite according to the present invention;

FIG. 3d is a schematic diagram of the maximum lateral swinging angle of the present invention;

FIG. 4a is a schematic diagram of a right down-tilt longest basic coverage pattern according to the present invention;

FIG. 4b is a schematic diagram of a left down-tilt longest basic coverage pattern according to the present invention;

FIG. 5a is a schematic view of the calculation of yaw angle under one aspect of the present invention;

FIG. 5b is a schematic view of the calculation of the yaw angle according to another aspect of the present invention;

FIG. 6a is a schematic diagram of the reduction of the length of the overlay mode according to the present invention;

FIG. 6b is a schematic diagram of the reduction of the length of the overlay mode according to the present invention in FIG. 2.

Detailed Description

As shown in fig. 2a, 2b, and 2c, in the present embodiment, a partitioned satellite mission planning method for completely covering a regional target at a minimum cost is applied to coverage mode planning in which a sufficient set of coverage engines S completely covers a rectangular region R to be observed and the coverage cost is as low as possible, where a coverage opportunity refers to an opportunity at which a satellite can perform coverage observation by passing through the space above the rectangular region to be observed. As shown in fig. 2c, the area of the rectangular region R to be observed is large, and a single coverage opportunity can cover only a small part, so that multiple coverage opportunities are required to be observed cooperatively.

As shown in fig. 3a, 3b, 3c, 3d, each coverage opportunity S e S has its own attributes, including: orbit of points under the satellite o_sSatellite ground clearance h_sMaximum boot time m_sAnd m is_sMaximum length r corresponding to one coverage pattern_sMaximum side-swinging angle v_sAngle of view w of camera_s(ii) a The trajectory of the satellite around the earth, the point directly below which forms on the ground, should in fact be curved, but can be considered approximately as a straight line within a small range inside the rectangular area to be observed, and for the sake of simplicity, this document will cover the trajectory o of the point below the satellite of the opportunity_sThe straight line is regarded as;

the coverage mode c is a rectangular strip formed by satellite shooting and is selected by a coverage opportunityIs determined based on the on-off time, the coverage cost of a coverage opportunity is in direct proportion to the length of the coverage mode selected by the coverage opportunity, and the proportionality coefficient is

Taking any vertex of a rectangular region R to be observed as an original point o, and taking two edges adjacent to the original point as an x axis and a y axis respectively, so as to establish a coordinate system o-xy; the coordinates of four vertices of the rectangular region R to be observed are denoted as top left vertex lu (R), bottom left vertex ld (R), top right vertex ru (R), and bottom right vertex rd (R), respectively; as shown in fig. 1, the partition satellite mission planning method is performed according to the following steps:

step 1: partitioning a rectangular region R to be observed;

step 1.1: set the length L of each partition_pAnd width W_p；

Then D will be_W+1 assignment to D_W；

Step 1.5: according to the length L of the final partition_fAnd width W_fAveragely partitioning the rectangular region R to be observed so as to obtain four tops of each partitionPoint coordinates;

Step 1.5.2: dividing the ith into n_iCoordinates LU (n) of the upper left corner of_i) Is added with L_fGet its right upper corner coordinates RU (n)_i) Let us coordinate LU (n) in the upper left corner_i) Is added with W_fObtain the coordinates LD (n) of the lower left corner_i) Then, the coordinate RU (n) at the upper right corner_i) Is added with W_fObtain its lower right coordinate RD (n)_i)；

Step 2: allocating observation resources to different partitions and selecting a coverage mode for the observation resources so as to minimize the coverage cost corresponding to the formed coverage scheme as much as possible; that is, different coverage opportunities are responsible for covering different partitions, and different allocation schemes eventually bring different coverage schemes, which correspond to different coverage costs, so that the optimal allocation scheme is searched by using a simulated annealing method.

step 2.2.1: taking each different partition and the set of coverage opportunities distributed to the different partitions as input, constructing a grid and calculating local better coverage schemes and corresponding coverage costs of the different partitions by using a heuristic algorithm;

step 2.2.1.1: dividing the ith into n_iDividing the cell into a plurality of square cells with the same size to obtain a cell set J_i(ii) a Wherein the side length of each cell should be sufficiently small. To ensure that there are cells that can be completely covered by the cover pattern.

Without direct calculation of the partitions, when the area to be observed is large, a large number of cells are generated. A large number of coverage patterns are generated based on these cells, consuming a large amount of computing resources. Some large-scale examples cannot solve the solution even in a reasonable time, so a partition-based solution strategy is proposed herein.

Step 2.2.1.2: according to the divided cell set J_iIs assigned to the ith partition n_iCovering opportunity set S_iGenerating basic coverage patterns and composing a total set C of its optional coverage patterns_i；

As shown in fig. 4a and 4b, the basic coverage mode refers to: the following three cells are present inside:

the four vertexes are all in the area covered by the covering mode;

each coverage opportunity may select an infinite number of on/off times and yaw angle values, so each coverage opportunity actually corresponds to an infinite number of coverage modes. However, since all coverage patterns cannot be enumerated, it is difficult to design a solution method for the problem based on the entire set of all coverage patterns. Basic coverage patterns are a special class of coverage patterns that can replace most non-basic coverage patterns and are limited in number. Most of the non-basic coverage patterns can be slightly adjusted to be converted into the corresponding basic coverage patterns, so that the cells with complete coverage are not reduced. Therefore, the basic coverage pattern set is used as the total set of the selectable coverage patterns, so that the continuous space optimization problem is converted into the discrete space optimization problem.

Step 2.2.1.2.1: if it is not

Go to step 2.2.1.2.4, otherwise go to step 2.2.1.2.2;

step 2.2.1.2.2: selecting one of the covering opportunities S E S_iConstructing a cell-based set J for the coverage opportunity s using a corresponding method, depending on the type of coverage opportunity s_iBasic coverage pattern set C_s：

Step 2.2.1.2.2.1: from the subsatellite point trajectory o of the coverage opportunity s_sJudging the type of the covering opportunity s, wherein the type of the covering opportunity s is divided into a right downward inclined type and a left downward inclined type;

step 2.2.1.2.2.2: order set

Step 2.2.1.2.2.3: from set of cells J_iMiddle screening subset J_sAnd subset J_sEach cell in (a) may be the left cell of the longest basic coverage pattern covering opportunity s;

step 2.2.1.2.2.3.1: order to

Step 2.2.1.2.2.3.2: traverse set J_iCalculating the camera yaw angle of the coverage opportunity s when each cell u is taken as the left cell of the coverage pattern

If the coverage chance is a right-lower angle tilt type, as shown in fig. 4a, then

The lower left corner vertex LD (u) of cell u and the sub-satellite point locus o covering the opportunity s_sIf the covering opportunity is of a downward left-inclined type as shown in FIG. 4b, the distance therebetween is set to be shorter

Step 2.2.1.2.2.4: if it is not

Go to step 2.2.1.2.2.13, otherwise, select J_sStep 2.2.1.2.2.5 is performed after one cell p;

step 2.2.1.2.2.5: from set of cells J, according to cell p_iMiddle screening out cell subset

And when p is taken as the left cell

Each of (1) toEach cell can be used as an upper cell and forms a basic coverage mode of a coverage opportunity s together with p;

step 2.2.1.2.2.5.1: order to

Step 2.2.1.2.2.5.2: calculating the stripe width η of the overlay mode using equation (1) for cell p as the left cell_s(p)：

As shown in FIGS. 5a and 5b, when cell u is the left cell of the overlay mode, the camera roll angle σ of the overlay opportunity s_s(u), and a band width η of the overlay mode_sThe calculation formula of (u) can be derived from elementary geometry. Wherein OB is the perpendicular bisector and the length of OB is the height of the satellite from the ground, i.e. h_s. The length of AB is a straight line L_uAnd o_sIs a distance therebetween, i.e.

Obviously, angle ABO is a right angle, and therefore, it is easy to find:

side-swinging angle of camera

In FIG. 5a, angle AOC is the field angle, i.e. w_sAnd < AOB > w_sThe width of the strip, at this point, is the length of the AC,

in FIG. 5b, angle AOD is the field angle, i.e. w_sAnd OC is the angular bisector of < AOD, i.e.

The width of the strip at this time is the length of AD.

∠DOB＝w_sMinus AOB, can obtain: BD ═ h_sTan & lt DOB, and then the following can be obtained:

step 2.2.1.2.2.5.3: traverse set J_iChecking whether one cell t meets the following four conditions, and if all the conditions are met, adding the cell t into the cell

Otherwise, the next cell to check continues:

Then straight line

At L_pRight side of (c);

Then straight line

② drawing straight lines L 'by respectively passing top points at the upper right corners of the cells p and t'_p⊥o_sAnd L_t⊥o_sThen L is_tL'_pAbove (1);

drawing straight line through top left corner vertex of cell t

Then straight line

At L_pRight side of (c);

Then straight line

obviously, cell p itself also satisfies these four conditions.

Step 2.2.1.2.2.6: if it is not

Go to step 2.2.1.2.2.12, otherwise, choose to

After one cell q, step 2.2.1.2.2.7 is performed;

step 2.2.1.2.2.7: from set of cells J, based on cells p and q_iMiddle screening out cell subset

And when p is the left cell and q is the upper cell, the subset of cells

step 2.2.1.2.2.7.1: order to

Step 2.2.1.2.2.7.2: traverse set J_iChecking whether one cell a meets the following four conditions, and if all the conditions are met, adding the cell a

Otherwise, the next cell to check continues:

② drawing straight lines L 'by respectively passing top left corners of cells p and a'_p⊥o_sAnd

then

L'_pBelow (1);

Then straight line

At L_pRight side of (c);

drawing a straight line L through the vertex of the lower right corner of the cell a_a⊥o_sDrawing a straight line L at the top left corner vertex of the t_t⊥o_sThen straight line L_aAnd L_tMust not exceed the strip length l_s(ii) a Where "|" represents a parallel relationship, and "|" represents a vertical relationship.

then

L'_pBelow (1);

drawing straight line through top left corner vertex of cell a

Then straight line

At L_pRight side of (c);

Obviously, cell p and cell q themselves also satisfy these four conditions.

Step 2.2.1.2.2.8: if it is not

Go to step 2.2.1.2.2.11, otherwise, choose to

Step 2.2.1.2.2.9 is performed after one cell b;

step 2.2.1.2.2.9: constructing a basic coverage c belonging to a coverage opportunity s based on cells p, q and b_s(p,q,b)；

Step 2.2.1.2.2.9.1: if the coverage chance is a lower right angle oblique type, then pass through the lower left corner vertex LD (p) of the cell p and make a straight line L_p‖o_sDrawing a straight line L through the top left vertex LU (q) of cell q_q⊥o_sDrawing a straight line L through the top RD (q) at the lower right corner of the cell b_b⊥o_sIf the coverage chance is of the lower left corner slope type, then go through the upper left corner vertex LU (p) of the cell p and make a straight line L_p‖o_sLine L is drawn through the top right vertex RU (q) of cell q_q⊥o_sDrawing a straight line L through the lower left corner vertex LD (q) of cell b_b⊥o_s；

Step 2.2.1.2.2.9.2: strip width η of overlay mode when calculating cell p as left cell_s(p)；

Step 2.2.1.2.2.9.3: make a straight line

So that it satisfies:

①

②

and L_pEqual to η_s(p)；

③

At L_pRight side of (c);

step 2.2.1.2.2.9.4: with L_p,

Step 2.2.1.2.2.10: c is to_s(p, q, b) addition of C_sUnit cell b from

Go to step 2.2.1.2.2.8;

step 2.2.1.2.2.11: cell q is selected from

Go to step 2.2.1.2.2.6;

step 2.2.1.2.2.12: cell p from J_sGo to step 2.2.1.2.2.4;

step 2.2.1.2.2.13: output overlay mode set C_s；

Step 2.2.1.2.3: will cover the opportunity S from S_iRemoving, go to step 2.2.1.2.1;

step 2.2.1.2.4: order to

Output overlay mode set C_i。

Step 2.2.1.3: with the ith partition n_iDivided set of cells J_iAnd optional coverage mode set C for each coverage opportunity_iSelecting the coverage mode of each coverage opportunity by a heuristic algorithm for input, thereby obtaining a better coverage mode set

And simultaneously derive its coverage cost P_i；

The heuristic algorithm uses a dynamic greedy-based rule to select the coverage mode with the maximum effective cost performance for coverage each time. Once an overlay mode is selected by an overlay opportunity, the overlay opportunity exits subsequent selection activities. Once a cell is covered in the previous selection round, the cell exits the subsequent selection activity. As shown in fig. 6a and 6b, if the upper cell or the lower cell of one overlay mode is "covered", the length of the overlay mode can be reduced to obtain an overlay mode with the same number of completely covered effective cells but with a lower overlay cost. The method is simple, quick and effective, and is very suitable for quickly obtaining a better and feasible coverage scheme under the current environment.

Step 2.2.1.3.1: let J_iThe state of all cells in the cell is "uncovered", and the cell is in the "uncovered" state

Step 2.2.1.3.2: let g be 1;

step 2.2.1.3.3: if g > | C_iIf not, go to step 2.2.1.3.5, otherwise continue, where | C_iI represents a set of optional coverage modes C_iThe number of elements in (1);

step 2.2.1.3.4: selection C_iAnd from the set of cells J_iSelecting cells which can be completely covered by the g-th coverage mode and have the state of 'uncovered', recording the cells as an effective cell set V (g) and the number of the cells as | V (g) |, and calculating the coverage cost of the g-th coverage mode

Wherein l_gFor the length of the g-th coverage pattern,

Namely the effective cost performance, assigning g +1 to g, and then turning to step 2.2.1.3.3;

step 2.2.1.3.5: if it is

Or if the states of all cells are "covered", go to step 2.2.1.3.8, otherwise go to step 2.2.1.3.6;

the coverage opportunities that are randomly assigned to each partition generally have the ability to fully cover the partition, provided the coverage opportunities are sufficient. If the situation that partial partitions cannot be completely covered occurs, the neighbor allocation scheme constructed by the insert operator and the exchange operator in the simulated annealing stage is improved.

Step 2.2.1.3.6: selection C_iMedium effective cost ratio maximum covering mode

step 2.2.1.3.7: will cover the opportunity s^*Corresponding set of coverage patterns

From alternative overlay modesSet C_iIs removed from C_iScreening out the coverage mode subset C ' with the upper cell or lower cell status as ' covered '_iAnd from C_iGo to step 2.2.1.3.2;

step 2.2.1.3.8: outputting a set of coverage patterns for each coverage opportunity selection

I.e. final coverage scheme, calculation

Step 2.2.2: overlay scheme for all partitions

The solution space of the allocation scheme is searched by a simulated annealing method so as to obtain a better allocation scheme and maximize the coverage area corresponding to the generated coverage scheme.

Step 2.3: setting a maximum number of iterations

step 2.4: if it is not

Step 2.9 is switched to, otherwise step 2.5 is executed;

step 2.5: randomly selecting a coverage opportunity

And based on coverage opportunities

step 2.5.1: order partition set

Representing an opportunity to remove coverage in a set of partitions N

step 2.5.2: if it is not

step 2.5.3: coverage opportunities to be selected in current allocation scheme Y

Randomly assigning to partition sets

Is a partition of

Thereby obtaining a neighbor allocation scheme

To be partitioned

From a set of partitions

Removing, and turning to the step 2.5.2;

step 2.5.4: outputting all the obtained neighbor scoresScheme of preparation

Herein will be described

Assigning to each unassigned partition to search through the entire neighborhood solution, further reducing the number of computations if needed can reduce the number of neighbor solutions constructed.

Step 2.7: comparative optimal neighbor allocation scheme

Cost of coverage with current allocation scheme Y, if

The optimal neighbor allocation scheme will be used

step 2.7.1: calculating inferior solution acceptance rate of kth iteration

Assigning a value to the current distribution scheme Y;

the magnitude of the annealing temperature represents the magnitude of randomness to the solution space search, and λ can be set larger and the number of iterations increased if the requirement on the final solution quality is high, and can be set smaller if fast convergence is required.

Claims

1. A partitioned satellite task planning method for minimum cost area target coverage is characterized by being applied to coverage mode planning for fully covering a rectangular area R to be observed by a sufficient coverage opportunity set S and enabling the coverage cost to be as small as possible, wherein each coverage opportunity S belongs to S and has own attribute, and the method comprises the following steps: orbit of points under the satellite o_sSatellite ground clearance h_sMaximum boot time m_sAnd m is_sMaximum length r corresponding to one coverage pattern_sMaximum side-swinging angle v_sAngle of view w of camera_s；

step 1: partitioning the rectangular region R to be observed;

step 1.1: set the length L of each partition_pAnd width W_p；

Then D will be_W+1 assignment to D_W；

step 2.3: setting a maximum number of iterations

step 2.4: if it is not

Step 2.9 is switched to, otherwise step 2.5 is executed;

step 2.5: randomly selecting a coverage opportunity

And based on coverage opportunities

Step 2.7: comparative optimal neighbor allocation scheme

Cost of coverage with current allocation scheme Y, if

The optimal neighbor allocation scheme will be used

step 2.7.1: calculating inferior solution acceptance rate of kth iteration

Assigning a value to the current distribution scheme Y;

2. The method for sectorized satellite mission planning according to claim 1, wherein said step 1.5 is performed as follows:

3. The method for sectorized satellite mission planning according to claim 1, wherein said step 2.5 is performed as follows:

step 2.5.1: order partition set

Representing an opportunity to remove coverage in a set of partitions N

step 2.5.2: if it is not

Randomly assigning to partition sets

Is a partition of

Thereby obtaining a neighbor allocation scheme

To be partitioned

From a set of partitions

Removing, and turning to the step 2.5.2;

step 2.5.4: outputting all resulting neighbor allocation schemes

4. The method of claim 1, wherein the step 2.2 and step 2.6 of calculating the preferred coverage mode set and corresponding coverage cost for each coverage opportunity selection given the allocation scheme is performed by:

the four vertexes are all in the area covered by the covering mode;

And simultaneously derive its coverage cost P_i；

Step b: overlay scheme for all partitions

5. The method of claim 4, wherein the step a.2 of generating the basic coverage patterns for the coverage opportunities based on the set of cells and forming the total set of optional coverage patterns is performed by:

step a.2.1: if it is not

Go to step a.2.4, otherwise execute step a.2.2;

step a.2.2: selecting one of the covering opportunities S E S_iConstructing a cell-based set J for the coverage opportunity s using a corresponding method, depending on the type of coverage opportunity s_iBasic coverage pattern set C_s：

step a.2.2.2: order set

step a.2.2.4: if it is not

And when p is taken as the left cell

step a.2.2.6: if it is not

Go to step a.2.2.12, otherwise, choose

Step a.2.2.7 is performed after one cell q;

And when p is the left cell and q is the upper cell, the subset of cells

step a.2.2.8: if it is not

Go to step a.2.2.11, otherwise, choose

Step a.2.2.9 is performed after one cell b;

Step a.2.2.10: c is to_s(p, q, b) addition of C_sUnit cell b from

Removing, and turning to the step a.2.2.8;

step a.2.2.11: cell q is selected from

Removing, and turning to the step a.2.2.6;

step a.2.2.12: cell p from J_sRemoving, and turning to the step a.2.2.4;

step a.2.2.13: output overlay mode set C_s；

step a.2.4: order to

Output overlay mode set C_i。

6. The method of claim 5, wherein step a.2.2.3 is performed as follows:

step a.2.2.3.1: order to

Wherein, if the covering chance is a right lower corner inclined type, then

7. The sectorized satellite mission planning method of claim 5,the method is characterized in that the step a.2.2.5 is carried out according to the following processes: step a.2.2.5.1: order to

Otherwise, the next cell to check continues:

Then straight line

At L_pRight side of (c);

Then straight line

drawing straight line through top left corner vertex of cell t

Then straight line

At L_pRight side of (c);

Then straight line

8. The method of claim 5, wherein the method comprisesCharacterized in that, the step a.2.2.7 is carried out according to the following process: step a.2.2.7.1: order to

Otherwise, the next cell to check continues:

then

L'_pBelow (1);

Then straight line

At L_pRight side of (c);

drawing a straight line L through the vertex of the lower right corner of the cell a_a⊥o_sDrawing a straight line L at the top left corner vertex of the t_t⊥o_sThen straight line L_aAnd L_tMust not exceedLength of passing strip l_s(ii) a Wherein, "|" represents a parallel relationship, and "|" represents a vertical relationship;

then

L'_pBelow (1);

drawing straight line through top left corner vertex of cell a

Then straight line

At L_pRight side of (c);

9. The method of claim 5, wherein step a.2.2.9 is performed as follows:

step a.2.2.9.1: if the coverage chance is a lower right angle oblique type, then pass through the lower left corner vertex LD (p) of the cell p and make a straight line L_p‖o_sOver cell qIs taken as a straight line L_q⊥o_sDrawing a straight line L through the top RD (q) at the lower right corner of the cell b_b⊥o_sIf the coverage chance is of the lower left corner slope type, then go through the upper left corner vertex LU (p) of the cell p and make a straight line L_p‖o_sLine L is drawn through the top right vertex RU (q) of cell q_q⊥o_sDrawing a straight line L through the lower left corner vertex LD (q) of cell b_b⊥o_s；

Step a.2.2.9.3: make a straight line

So that it satisfies:

①

②

and L_pEqual to η_s(p)；

③

At L_pRight side of (c);

step a.2.2.9.4: to be provided with

The four straight lines are used as four sides of the rectangle, the intersection points of the four straight lines are used as four vertexes of the rectangle, and the covering mode c is constructed_s(p,q,b)。

10. The method for sectorized satellite mission planning according to claim 4, wherein said step a.3 is performed as follows:

step a.3.1: let J_iThe state of all cells in the cell is "uncovered", order

Step a.3.2: let g be 1;

Wherein l_gFor the length of the g-th coverage pattern,

Assigning g +1 to g, and then turning to the step a.3.3;

step a.3.5: if it is

step a.3.6: selection C_iMedium effective cost ratio maximum covering mode

I.e. final coverage scheme, calculation