CN105841705A - Time-attitude based method for decomposition and synthesis of imaging satellite observation task - Google Patents

Abstract

The invention discloses a time-attitude-based imaging satellite observation task decomposition and synthesis method, which is characterized in that the steps are as follows: (1) determining the time-attitude vector of the target according to the latitude and longitude height of the point target and the position of the satellite; (2) ) Establish a circumscribed characteristic rectangle with a long side parallel to the sub-satellite line containing all target points as the regional target, and determine the pitch angle, and calculate the eigenvector of the regional target; (3) divide the strips according to the width of the satellite; (4) Trim the strips to the appropriate length according to the region target boundaries. This method can perform target decomposition and synthesis more intuitively and efficiently, and more conveniently generate meta-task information input into the task planning and scheduling model. A unified description method has a certain degree of operability, versatility and scalability.

Description

Decomposition and Synthesis Method of Imaging Satellite Observation Tasks Based on Time-Attitude

technical field

The invention relates to the field of satellite observation tasks, in particular to a time-attitude-based imaging satellite observation task decomposition and synthesis method.

Background technique

A complex problem in the preprocessing of imaging satellite mission planning is to establish the relationship between the satellite and the target. The reason for this complexity is that the target position, satellite position and satellite attitude are all described by different coordinate systems, and a large number of coordinates are required in the actual calculation process. However, these conversions only consider the spatial position and have no concept of time, and the time constraints and regularity of satellites flying in the air are very strong. Therefore, it is urgent to combine the spatial position, time and satellite capabilities to provide a set of A new description method of satellite-target relationship.

Contents of the invention

In order to solve the above-mentioned problems in the existing satellite observation tasks, the purpose of the present invention is to provide a method that is easy to understand and calculate, and provides a unified description method for target decomposition and synthesis, which has certain operability, versatility and Scalable Time-Attitude Based Imaging Satellite Observation Task Decomposition and Synthesis Method.

To achieve the above object, the present invention provides the following technical solutions:

The time-attitude-based imaging satellite observation task decomposition and synthesis method, the steps are as follows: (1) determine the time-attitude vector of the target according to the latitude and longitude height of the point target and the position of the satellite; (2) establish a long-term vector containing all target points The circumscribed characteristic rectangle whose side is parallel to the sub-satellite line is used as the regional target, and the pitch angle is determined to calculate the eigenvector of the regional target; (3) divide the strips according to the width of the satellite; (4) cut the strips into Appropriate length.

Further, the specific operation method of step (4) is: find the target vertex in the strip, then calculate the intersection point of the strip and the area target, and finally find out out the earliest time and the latest

Furthermore, step (5) is included between step (2) and step (3): merging at least two regional objects.

Furthermore, the specific operation method of each step is as follows:

(1) The latitude and longitude heights of the point target (Target) in the WGS84 coordinate system are b, l, and h respectively, and the position of the satellite at time t in the J2000 geocentric inertial coordinate system is The pointing attitude of the satellite to the target at time t in the orbital coordinate system is The corresponding relationship between the position of the satellite and the time point is

The corresponding relationship between the position of the target and the pointing attitude of the satellite to the target at a certain position is

Therefore, the target position can be expressed by the function F of the pointing attitude of the satellite to the target at a certain moment, namely

The function variable on the right side of the above formula is abbreviated as (t, r, p, y) _Target , which is called the "time-attitude" vector of the satellite to a certain point, referred to as the time-attitude vector, denoted as v, and for non-agile satellites, p = 0, the time and attitude vector degenerates into a "time-sway" vector (t,r) _Target , referred to as the zero time and attitude vector, denoted as

(2) Two feature points on the broad side determine the length of the rectangle, which is characterized by being at the extreme ends of the vertical feet of the vertices of the entire area to the satellite line. When it is directly above the foot, it is said that the satellite passes the top, so the two feature points that determine the length of the rectangle are the two points where the satellite passes the top at the earliest t ^e and the latest t ^l , which are respectively denoted as e ^e and e ^l , and the satellite flight speed is approximately As a constant speed, if the pitch angle of the satellite is fixed, that is, p=p ₀ , then the length of the rectangle is transformed into a representation of time, that is

The two feature points on the long side determine the width of the rectangle, which are characterized by the two points with the maximum r ⁺ and minimum r ^- of the roll angle when the vertex of the satellite is over the top of the entire area, which are respectively recorded as e ⁺ and e ^- , If the pitch angle of the satellite is fixed, such as p=p ₀ , then the width of the rectangle is transformed into the representation of the roll angle of the satellite, namely

The characteristic rectangle is actually represented by only four quantities, that is, the earliest moment latest moment minimum roll angle maximum roll angle written in vector form is called the eigenvector when the pitch angle is p ₀ , when p ₀ =0, that is, the satellite has no pitch capability, and the eigenvector degenerates to That is, the eigenvector when the pitch angle is 0, referred to as the zero eigenvector;

(3) The width of the strip is directly represented by the field angle δ of the imaging load, so that the strip is described by the zero eigenvector, that is where (r ⁺ -r ^- ) _strip = δ;

If the strips are divided one by one from the side with the smallest side swing strictly according to the given redundancy angle, there will often be a large redundancy on one side, and the final large redundancy will be evenly distributed to each redundancy to obtain a reconciled redundancy angle Δδ'≥Δδ, to further reduce the risk of leaking corners or gaps due to errors at each redundancy, use

Indicates the ratio of the distance between adjacent stripes to the width, which is called the stripe division granularity,

When the specified striping granularity is g, the The characteristic rectangle divides the strips, and the number of strips divided is Its harmonic redundancy angle is

Therefore, the zero eigenvector of strip i The minimum and maximum roll angles in

(4) Traversing the target vertex, for vertex i if Then record vertex i, otherwise discard vertex i and continue to judge vertex i+1; for vertex i if and or and Then it shows that the edge composed of vertex i and vertex i±1 intersects the strip, and starts to calculate the zero-time attitude vector of the intersection point, that is, the side swing of the intersection point is equal to the side swing of the intersecting side, and then calculate the intersection point through similar triangles time, record the intersection point, and continue to determine the target vertex;

If all the vertices have been traversed, find out the earliest and latest time of the strip, compare the time values of all recorded vertices and intersections, and obtain the earliest time of the strip and the latest After such strip clipping for each strip, the target decomposition is complete.

Furthermore, the following conditions are used to combine the regional targets: described by time and roll range, that is, a single strip with the largest zero eigenvector to be satisfied

The condition of target synthesis is the zero-time attitude vector of the point target or zero eigenvectors of region targets no more than a single strip of the largest zero eigenvector, i.e.

The present invention has the following beneficial effects: (1) according to the space-time relationship between the satellite and the target, the present invention proposes a point target description method based on time-attitude, and extends it to the regional target description method, and converts the geographic coordinates of the target into the satellite itself The information in the two orthogonal dimensions of time and attitude can be more intuitive and efficient for target decomposition and synthesis, and more conveniently generate meta-task information input into the task planning and scheduling model; the proposed time-attitude concept is not only easy to understand and calculation, and provides a unified description method for target decomposition and synthesis, which has certain operability, versatility and scalability; (2) using the time-attitude method to determine the circumscribed rectangle of the regional target The eigenvector of the target in the area, and a fixed pitch angle needs to be selected. Generally, zero pitch is used, that is, the zero eigenvector is used. The zero eigenvector is more versatile: on the one hand, the zero eigenvector naturally represents a non-agile satellite without pitching capability, and has good compatibility; on the other hand, for an agile satellite whose height from the ground is h and the camera field of view is δ, Considering the ground approximately as a plane, when the pitch angle and yaw angle are 0, the relationship between its width d and the pitch angle p of the satellite is It is easy to find that when p=0, d takes the minimum value, that is, the corresponding width is the smallest when the pitch angle is 0. Although agile satellites have different widths corresponding to different pitch angles, since it is not known in the preprocessing stage when the satellite is on the target Imaging, so using the strips divided by the width when the pitch angle is 0 can ensure that the imaging strips are not smaller than the strips with the minimum width at any time and under any pitch angle; (3) After the strips are divided, we get A group of strips of equal length can be cut according to the needs of users to improve the effective coverage of the strips; (4) for some point targets or area targets that are very close, if each Processing alone will generate many small bands, which not only increases the search space in the planning stage, but also wastes time due to frequent satellite attitude maneuvers, resulting in many tasks that can be observed that cannot be observed. Therefore, these targets need to be merged, and the bands Observing two targets at a time, although the effective coverage rate is reduced, but one more target is observed, and the income increases.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are For some embodiments of the present invention, those skilled in the art can also obtain other drawings based on these drawings without creative work.

Accompanying drawing 1 is the characteristic point and characteristic rectangle of the embodiment of the present invention.

Accompanying drawing 2 is the target decomposition step of the embodiment of the present invention.

Accompanying drawing 3 is the effect of the pitch angle on the width of the embodiment of the present invention.

Accompanying drawing 4 is the effect of the roll angle on the width of the embodiment of the present invention.

FIG. 5 is a schematic diagram of stripe division for avoiding errors according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of stripe division for avoiding uneven redundancy according to an embodiment of the present invention.

Figure 7 is a schematic diagram of strip cutting according to the embodiment of the present invention.

Figure 8 is a schematic diagram of synthetic observation of non-agile satellite targets according to an embodiment of the present invention.

Accompanying drawing 9 is the situation of invalid synthesis of the embodiment of the present invention.

Accompanying drawing 10 is the synoptic observation diagram of the agile satellite of the embodiment of the present invention.

Accompanying drawing 11 is the target decomposition result of the embodiment of the present invention.

detailed description

The present invention will be further described below by specific examples.

Time-attitude vector of 1-point target

The latitude and longitude heights of the point target (Target) in the WGS84 coordinate system are b, l, and h respectively, and the position of the satellite at time t in the J2000 geocentric inertial coordinate system is The pointing attitude of the satellite to the target at time t in the orbital coordinate system is When calculating the positional relationship between the satellite and the target, they can be transformed into a coordinate system.

For a satellite flying normally, the position of the satellite is a function of time, and the position of the satellite at a certain time in the future can be predicted by using the high-precision ephemeris prediction method, that is, the position of the satellite corresponds to the time point one by one:

The position of the target can be converted to the position in the satellite orbit coordinate system at a certain moment, so the position of the target corresponds to the pointing attitude of the satellite to the target at a certain position:

From formula (1) and formula (2), it can be seen that the target position can be expressed by the function F of the pointing attitude of the satellite to the target at a certain moment, that is,

The function variable on the right side of the above formula is abbreviated as (t, r, p, y) _Target , which is called the "time-attitude" vector of the satellite to a certain point, referred to as the time-attitude vector, denoted as v. For non-agile satellites, if p=0, the time and attitude vector degenerates into a "time-sway" vector (t, r) _Target , referred to as the zero time and attitude vector, denoted as

2 Eigenvectors of regional targets

The area can be regarded as a closed figure surrounded by multiple points, so the area target can be expressed as a set of target points, that is, Area:{Target ₁ ,Target ₂ ,...,Target _n }, each target point Using time and attitude vector representation, the regional target can be recorded as Area: {(t,r,p,y) ₁ ,(t,r,p,y) ₂ ,...,(t,r,p,y) _n }.

Since the satellite imaging strip is parallel to the off-satellite line, the regional target decomposition generally needs to establish a circumscribed rectangle whose long side is parallel to the off-satellite line as shown in Figure 1. This rectangle can completely cover the target area, and has satellites and targets There are many characteristics in the regional relationship, so this paper calls the circumscribed rectangle the characteristic rectangle of the regional target, and defines the length of the characteristic rectangle as the side parallel to the lower line of the star, and the width of the characteristic rectangle as the side perpendicular to the lower line of the star. The determination of the rectangle is only related to the points where the area and the rectangle meet, so these points are called the feature points of the area target in this paper, denoted as e.

As shown in Figure 1, the two feature points on the broad side determine the length of the rectangle, which is characterized by being at the extreme ends of the vertical feet of the vertex in the entire area. When it is directly above the vertical foot of the line, it is said that the satellite passes the top, so the two characteristic points that determine the length of the rectangle are the two points where the satellite passes the top at the earliest t ^e and the latest t ^l , which are respectively denoted as e ^e and e ^l , and the satellite The flight speed can be approximated as a constant speed. If the pitch angle of the satellite is fixed (such as p=p ₀ ), the length of the rectangle can be transformed into a representation of time, namely The two feature points on the long side determine the width of the rectangle, which are characterized by the two points with the maximum r ⁺ and minimum r ^- of the roll angle when the vertex of the satellite is over the top of the entire area, which are respectively recorded as e ⁺ and e ^- , If the pitch angle of the satellite is fixed (such as p=p ₀ ), the width of the rectangle can be transformed into the representation of the roll angle of the satellite, namely

Therefore, if the pitch angle of the satellite is fixed, the characteristic rectangle can actually be represented by only four quantities, that is, the earliest time latest moment minimum roll angle maximum roll angle written in vector form is called the eigenvector when the pitch angle is p ₀ , when p ₀ =0, that is, the satellite has no pitch capability, and the eigenvector degenerates to That is, the eigenvector when the pitch angle is 0, referred to as the zero eigenvector.

3 Decomposition and synthesis of goals

3.1 Target decomposition

The process of decomposing the target into meta-task strips is to first establish a circumscribing rectangle parallel to the off-satellite line, as shown in Figure 2(c), and then divide the strips according to the width of the satellite, as shown in Figure 2(b) , and finally cut the strip to an appropriate length according to the region target boundary, as shown in Fig. 2(c).

Target decomposition is one of the important functions in the preprocessing of imaging satellite missions. It has always been a complicated problem in preprocessing. At present, many regional target decomposition methods do not consider the capabilities of the satellite itself and the pointing attitude of the satellite. The decomposition method based on Gaussian projection The error is large, and the decomposition method based on spatial geometry has a large computational complexity. The decomposition method based on MapX needs to rely on third-party software, and the time-attitude description method proposed in this paper can solve these problems well. Next, based on The time-pose object decomposition method is described in detail.

3.1.1 Determine the circumscribed rectangle

According to the above definition, using the time-attitude method to determine the circumscribed rectangle of the regional target is actually to find the eigenvector of the regional target, and a fixed pitch angle needs to be selected. Generally, zero pitch is used, that is, the zero eigenvector is used.

The following shows that the zero eigenvector is more versatile from two aspects: on the one hand, the zero eigenvector naturally represents a non-agile satellite with no pitch capability, and has good compatibility; For an agile satellite with δ, the ground is approximately regarded as a plane. When the pitch angle and yaw angle are 0, the relationship between its width d and the pitch angle p of the satellite is

It is easy to find that when p=0, d takes the minimum value, that is, the corresponding width is the smallest when the pitch angle is 0. Although agile satellites have different widths corresponding to different pitch angles, since the satellite does not know when the satellite is on the target in the preprocessing stage Imaging, so using the strips divided by the width when the pitch angle is 0 can ensure that the imaging strips are not smaller than the strips with the minimum width at any time and under any pitch angle, as shown in Figure 3, so in the division When striping, select the width when the pitch angle is 0.

3.1.2 Striping

The characteristic rectangle can be obtained by calculating the zero eigenvector of the target to a certain star and certain orbit, and then the characteristic rectangle needs to be divided into strips.

Some people divide the strips with a fixed width without taking into account the influence of satellite side swing on its imaging width. The field angle is δ, the satellite roll angle is r, the pitch angle and yaw angle are both 0, then the imaging width d is

When R=6400, h=700, δ=2°, the change of d with r and p is obtained from formula (5) and formula (4), as shown in Table 1, it can be seen that r has a significant influence on d, so the amplitude The width is fixed to the width when the side swing is 0, and the strip division will cause a lot of waste.

Table 1 The change table of d with r and p

In order to overcome the disadvantage of dividing strips with a fixed width, the width of the strip can be directly represented by the field angle of the imaging load, so that the strip can also be described by a zero eigenvector, that is, Where (r ⁺ -r ^- ) _strip = δ, which not only maintains the consistency of the description, but also simplifies the calculation. Different strips only need to decrease in order according to the field angle of the imaging load.

In order to avoid errors causing gaps or missing corners between adjacent strips as shown in Figure 5(a), the adjacent strips can be overlapped and expanded to both sides to leave redundancy, as shown in Figure 5( As shown in b), the width of the redundant part is also represented by an angle, which is called the redundant angle and is denoted as Δδ. Thus, as shown in Figure 5(b), the zero eigenvector of strip 1 is

However, if the strips are divided one by one from the side with the smallest side swing strictly according to the given redundancy angle, the large redundancy on one side will often appear as shown in Figure 6(a). If the last large redundancy is evenly distributed to For each redundancy, as shown in Figure 6(b), the harmonic redundancy angle Δδ'≥Δδ can be obtained, which can further reduce the risk of leaking angles or gaps due to errors at each redundancy. Generally used in actual engineering

Indicates the ratio of the distance between adjacent stripes to the width, which is called the stripe division granularity.

When the specified striping granularity is g, the The characteristic rectangle divides the strips, and the number of strips divided is

Its harmonic redundancy angle is

Therefore, the zero eigenvector of strip i The minimum and maximum roll angles in

3.1.3 Strip clipping

After the strips are divided, a group of equal-length strips is obtained. According to the user's needs, the strips can be cut according to the target edge to improve the effective coverage of the strips. Based on MapX ^[70] and spatial geometry ^[71] , Liu Xiaodong finds the intersection point of the strip and the area target to cut the strip. The former requires third-party software, and the latter requires complex spatial geometry calculations. The length of is converted into a time description, and the strip clipping can still be performed using the description method of the time and pose vector.

For strip clipping under the time and pose description of a strip, firstly find the target vertices in the strip, then calculate the intersection point between the strip and the area target, and finally find out the earliest time and the latest As shown in Figure 7, the specific steps of clipping strip 4 are as follows:

Step1: Traverse the target vertex. For vertex i if Then record vertex i, otherwise discard vertex i, jump back to Step1 and continue to judge vertex i+1; for vertex i if and or and It means that the edge composed of vertex i and vertex i±1 intersects the strip, and then go to Step2 to calculate the zero-time pose vector of the intersection point; if all vertices have been traversed, skip to Step3.

Step2: Calculate the zero-time pose vector of the intersection point. The side swing of the intersection point is equal to the side swing of the intersecting side, and then find the moment of intersection through similar triangles, record the intersection point, and jump back to Step1. For example, the zero-time attitude vector of the intersection point P shown in Figure 7

The specific solution process is as follows:

Step3: Find the earliest and latest time of the strip. Compare the time values of all recorded vertices and intersections to get the earliest time of the strip and the latest

After such strip clipping for each strip, the target decomposition is complete.

3.2 Target synthesis

Different from target decomposition, some point targets or regional targets that are very close, if each target is processed separately, many small strips will be generated, which not only increases the search space in the planning stage, but also wastes time due to frequent satellite attitude maneuvers , resulting in many tasks that could have been observed cannot be observed, so these objectives need to be combined.

For example, for the two targets shown in Figure 8(a), according to the previous decomposition method, two small strips will be divided with each target as the center of the strip, and the satellite needs to swing to the attitude of strip 2 after sweeping strip 1 To observe target 2, for non-agile satellites, its side swing speed is slow, and due to energy constraints, the number of swings per circle is limited, so it may not be possible to observe target 2, and if the two targets are offline in the vertical star If the distance span in the direction does not exceed the width of the satellite, the two targets can be observed together, and the two targets can be observed by scanning the strips as shown in Figure 8(b). Although the effective coverage is reduced, the multi-observation A goal is achieved, and the income increases.

However, it does not mean that the distance between targets can be effectively synthesized, and the constraints of many satellites must be satisfied. As shown in Figure 9(a), although target 1 and target 2 are very close, target 2 is beyond the visible range of the satellite. The width of the strip should be avoided, and the situation beyond the visible range of the satellite should be avoided; the situation shown in Figure 9(b) may appear in the direction along the sub-satellite line, although the targets 1, 2 and 3 are all visible and in a single field of view Among them, but because satellites generally have the constraint of the longest single imaging time T _max , multiple targets cannot be synthesized into too long strips.

Since the target synthesis is only constrained along the sub-star line and perpendicular to the sub-star line, it can also be described by time and side swing range, that is, a single-strip maximum zero eigenvector to be satisfied

The condition of target synthesis is the zero-time attitude vector of the point target or zero eigenvectors of region targets no more than a single strip of the largest zero eigenvector, i.e.

Synthetic observation is not only significant for non-agile satellites, but also for agile satellites. For the two targets shown in Figure 10(a), a total of 4 strips are required for separate observations. The target composite observation shown in the figure only needs three strips. Although some invalid coverage is added, reducing one attitude maneuver can save a lot of time and onboard energy.

The synthesis method proposed above only considers the geographical location of the target. The task synthesis in practical problems also needs to consider the synthesis of other attributes such as task requirements and priorities. The tasks in the preprocessing process are collectively called static synthesis, because static synthesis It cannot be adjusted according to the actual satellite scheduling situation, so the method of dynamic synthesis is generally adopted, and task synthesis is put into the task planning process. The specific synthesis strategy is related to the task planning and scheduling algorithm, so this article does not give a specific synthesis method, only introduces A task synthesis judgment method based on time-attitude description is proposed. Because most of the mission planning models consider time and satellite attitude, this description method is more convenient for direct calculation and judgment in the planning and scheduling process.

4. Experiment and result analysis

The parameters of a certain satellite are shown in Table 2, and the areas and requirements to be decomposed are shown in Table 3.

Table 2 Simulation parameters of an agile satellite and its imaging payload

Table 3 detailed inspection demand information table

The target decomposition results using the method proposed in this paper are shown in Figure 11. The dark gray area is the divided strip, and the covered light gray parallelogram is the area to be decomposed.

Table 2 Strip information

In this paper, specific examples are used to illustrate the principles and implementation modes of the present invention, and the descriptions of the above examples are only used to help understand the methods and core ideas of the present invention. The above is only a preferred embodiment of the present invention. It should be pointed out that due to the limitation of literal expression, there are objectively unlimited specific structures. Under these circumstances, several improvements, modifications or changes can also be made, and the above-mentioned technical features can also be combined in an appropriate manner; these improvements, modifications, or combinations, or the idea and technical solution of the invention can be directly applied to other occasions without improvement should be regarded as the protection scope of the present invention.

Claims (5)

1. The imaging satellite observation task decomposition and synthesis method based on time-attitude is characterized in that the steps are as follows: (1) determine the time-attitude vector of the target according to the latitude and longitude height of the point target and the position of the satellite; One of the long sides of the target point is parallel to the circumscribed feature rectangle of the satellite line as the regional target, and the pitch angle is determined to calculate the feature vector of the regional target; (3) divide the strips according to the width of the satellite; (4) according to the boundary of the regional target Cut the strips to the appropriate length. 2. The imaging satellite observation task decomposition and synthesis method based on time-attitude according to claim 1, characterized in that, the specific operation method of step (4) is: find the target vertex in the strip, and then calculate the strip Intersect with the area target, and finally find the earliest time by comparing the time-attitude vector of these vertices with the zero pitch angle of the intersection and the latest 3. The time-attitude-based imaging satellite observation task decomposition and synthesis method according to claim 1, wherein step (5) is included between step (2) and step (3): for at least two regional targets to merge. 4. according to the time-attitude-based imaging satellite observation task decomposition and synthesis method described in any one of claim 1-3, it is characterized in that, the specific operation method of each step is: (1) The latitude and longitude heights of the point target (Target) in the WGS84 coordinate system are b, l, and h respectively, and the position of the satellite at time t in the J2000 geocentric inertial coordinate system is The pointing attitude of the satellite to the target at time t in the orbital coordinate system is The corresponding relationship between the position of the satellite and the time point is $\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; \&LeftRightArrow;</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; J</span>}\mathrm{<span\; class="notranslate">\; 2000</span>}}<span\; class="notranslate">\; ,</span>$ The corresponding relationship between the position of the target and the pointing attitude of the satellite to the target at a certain position is ${<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; T</span>}\mathrm{<span\; class="notranslate">\; arg</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; W</span>}\mathrm{<span\; class="notranslate">\; G</span>}\mathrm{<span\; class="notranslate">\; S</span>}\mathrm{<span\; class="notranslate">\; 84</span>}}<span\; class="notranslate">\; \&LeftRightArrow;</span><span\; class="notranslate">\; (</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; J</span>}\mathrm{<span\; class="notranslate">\; 2000</span>}}<span\; class="notranslate">\; ,</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; T</span>}\mathrm{<span\; class="notranslate">\; arg</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; b</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$ Therefore, the target position can be expressed by the function F of the pointing attitude of the satellite to the target at a certain moment, namely ${<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; T</span>}\mathrm{<span\; class="notranslate">\; arg</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; W</span>}\mathrm{<span\; class="notranslate">\; G</span>}\mathrm{<span\; class="notranslate">\; S</span>}\mathrm{<span\; class="notranslate">\; 84</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; T</span>}\mathrm{<span\; class="notranslate">\; arg</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; b</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>$ The function variable on the right side of the above formula is abbreviated as (t, r, p, y) _Target , which is called the "time-attitude" vector of the satellite to a certain point, referred to as the time-attitude vector, denoted as v, and for non-agile satellites, p = 0, the time and attitude vector degenerates into a "time-sway" vector (t,r) _Target , referred to as the zero time and attitude vector, denoted as (2) Two feature points on the broad side determine the length of the rectangle, which is characterized by being at the extreme ends of the vertical feet of the vertices of the entire area to the satellite line. When it is directly above the foot, it is said that the satellite passes the top, so the two feature points that determine the length of the rectangle are the two points where the satellite passes the top at the earliest t ^e and the latest t ^l , which are respectively denoted as e ^e and e ^l , and the satellite flight speed is approximately As a constant speed, if the pitch angle of the satellite is fixed, that is, p=p ₀ , then the length of the rectangle is transformed into a representation of time, that is The two feature points on the long side determine the width of the rectangle, which are characterized by the two points with the maximum r ⁺ and minimum r ^- of the roll angle when the vertex of the satellite is over the top of the entire area, which are respectively recorded as e ⁺ and e ^- , If the pitch angle of the satellite is fixed, such as p=p ₀ , then the width of the rectangle is transformed into the representation of the roll angle of the satellite, namely The characteristic rectangle is actually represented by only four quantities, that is, the earliest moment latest moment minimum roll angle maximum roll angle written in vector form is called the eigenvector when the pitch angle is p ₀ , when p ₀ =0, that is, the satellite has no pitch capability, and the eigenvector degenerates to That is, the eigenvector when the pitch angle is 0, referred to as the zero eigenvector; (3) The width of the strip is directly represented by the field angle δ of the imaging load, so that the strip is described by the zero eigenvector, that is where (r ⁺ -r ^- ) _strip = δ; If the strips are divided one by one from the side with the smallest side swing strictly according to the given redundancy angle, there will often be a large redundancy on one side, and the final large redundancy will be evenly distributed to each redundancy to obtain a reconciled redundancy angle Δδ'≥Δδ, to further reduce the risk of leaking corners or gaps due to errors at each redundancy, use $\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}}{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}$ Indicates the ratio of the distance between adjacent stripes to the width, which is called the stripe division granularity, When the specified striping granularity is g, the The characteristic rectangle divides the strips, and the number of strips divided is Its harmonic redundancy angle is ${\mathrm{<span\; class="notranslate">\; \&Delta;\&delta;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; r</span>}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; r</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>$ Therefore, the zero eigenvector of strip i The minimum and maximum roll angles in $\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; r</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&delta;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&delta;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}\end{array}\right.<span\; class="notranslate">\; ;</span>$ (4) Traversing the target vertex, for vertex i if Then record vertex i, otherwise discard vertex i and continue to judge vertex i+1; for vertex i if and or and Then it shows that the edge composed of vertex i and vertex i±1 intersects the strip, and starts to calculate the zero-time attitude vector of the intersection point, that is, the side swing of the intersection point is equal to the side swing of the intersecting side, and then calculate the intersection point through similar triangles time, record the intersection point, and continue to determine the target vertex; If all the vertices have been traversed, find out the earliest and latest time of the strip, compare the time values of all recorded vertices and intersections, and obtain the earliest time of the strip and the latest After such strip clipping for each strip, the target decomposition is complete. 5. The imaging satellite observation task decomposition and synthesis method based on time-attitude according to claim 4, wherein the merging of regional targets is carried out in the following situations: describe with time and side swing range, i.e. a single strip largest zero eigenvector to be satisfied $\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; x</span>}}\\ <span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; max</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; r</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; r</span>}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; max</span>}}\end{array}\right.$ The condition of target synthesis is the zero-time attitude vector of the point target or zero eigenvectors of region targets no more than a single strip of the largest zero eigenvector, i.e. $\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; l</span>}}\\ {\mathrm{<span\; class="notranslate">\; r</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; r</span>}}^{<span\; class="notranslate">\; +</span>}\end{array}\right.<span\; class="notranslate">\; .</span>$