A large-area shooting planning method for remote sensing satellites based on cloud images

Abstract

The present invention relates to a remote sensing satellite large-area shooting planning method based on cloud maps, comprising the steps of: determining the original large-area target range and the unphotographed range, and displaying them synchronously on a two-dimensional map, and setting planning conditions; calculating the satellite's photographable range, and displaying the photographable range and the satellite ground track on the two-dimensional map; selecting a preferred shooting strip according to the cloud map, the photographable range, and the unphotographed range corresponding to the transit window; fine-tuning the shooting duration and the side swing angle of the preferred shooting strip, and generating a shooting task according to the precise visible window information, shooting duration, and side swing angle of the fine-tuned preferred shooting strip. The present invention uses reference information such as the predicted regional cloud map and the effective data base map to accurately plan the shooting strip of each transit window, select the preferred shooting strip with better imaging conditions, improve the single data acquisition success rate and the overall regional coverage efficiency of the satellite's shooting of large-area targets, and effectively reduce the waste of satellite imaging resources.

Description

Technical Field

[0001] The invention belongs to the field of satellite remote sensing technology, and relates to a remote sensing satellite shooting task planning method, and specifically to a remote sensing satellite large-area shooting planning method based on cloud maps. Background Art

[0002] As a major means of obtaining information about the earth's surface, remote sensing has been widely used in agriculture, forestry, environment, geology, oceanography, meteorology, surveying and mapping, etc., due to its rich information and large coverage area. Satellite mission planning refers to the rational arrangement of satellite photography and data transmission tasks by considering various resources and demand factors, and is the main work of daily satellite operation and control management.

[0003] The targets to be photographed by satellites usually include two types: point targets and regional targets. Since point targets can be covered by a single satellite shot, the planning of point target shooting tasks is relatively simple. Regional targets require multiple satellite shots to cover them. Taking China as an example, high-resolution data coverage of the entire land area is usually a long-term shooting task. In addition, due to weather factors, especially cloud and fog coverage, not all shooting data can obtain effective ground object information. The complex weather and cloud cover factors in the region increase the difficulty of mission planning. Therefore, how to plan each specific shooting task for selecting regional targets has always been a major problem in the field of mission planning.

[0004] The common working mode for remote sensing satellites, especially optical remote sensing satellites, to perform shooting tasks is linear push-scanning. The shooting of regional targets needs to be decomposed into multiple sub-strips of single push-scanning shooting. Traditional regional shooting planning usually adopts the method of regional pre-decomposition. The first commonly used decomposition method is to decompose the region into parallel strips of fixed width based on the satellite's trajectory direction and the sensor width. Although this method is simple and easy to implement, it is only applicable to a single satellite or similar satellites with the same orbital inclination and width, and it makes the task scheduling between multiple strips more complicated. The second commonly used decomposition method is to decompose the region into multiple strips corresponding to specific transit windows based on the actual transit opportunity of the satellite. This method directly assigns the shooting strips to specific transit windows, contains the scheduling process between strips, and is applicable to multiple satellites. Whether it is a direct decomposition method based on satellite width or various optimized decomposition methods based on satellite transit opportunities, the weather and cloud factors of the region are not considered when decomposing the region. The effective utilization rate of satellite imaging resources and the overall efficiency of regional coverage tasks are generally low. It is only applicable to regional shooting coverage analysis, not to actual satellite large-area mission planning. Therefore, developing a large-area shooting planning method based on cloud images has great practical value for the rational use of satellite imaging resources. Summary of the invention

[0005] In order to solve the problems of low data acquisition efficiency and low regional coverage efficiency caused by cloud cover in traditional large-area target decomposition planning methods, the present invention provides a remote sensing satellite large-area shooting planning method based on cloud maps, which decomposes the area within each transit window of the satellite over the large area. Different from the traditional regional pre-decomposition method, this method uses the predicted cloud cover information as an important reference factor for selecting the shooting range, and can be regarded as a dynamic decomposition method based on the cloud cover information of each transit window. The main purpose of the present invention is to enable each shooting task to obtain the maximum effective coverage area in the area, thereby improving the overall coverage efficiency of regional targets.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A cloud map-based remote sensing satellite large-area shooting planning method comprises the following steps:

[0008] Step 1: determining an original large-area target range and an unphotographed range, and synchronously displaying the original large-area target range and the unphotographed range on a two-dimensional map, and setting planning conditions, wherein the planning conditions include a planning period, satellite resources, and a side swing angle limit;

[0009] Step 2: loading satellite tracks, calculating the shooting range of the satellite, and displaying the shooting range and the satellite ground track on the two-dimensional map;

[0010] Step 3: selecting a preferred shooting strip according to the cloud map corresponding to the transit window, the shootable range and the unshootable range;

[0011] Step 4: fine-tune the shooting duration and the side-swing angle of the preferred shooting strip, and generate a shooting task according to the precise visible window information of the fine-tuned preferred shooting strip, the shooting duration and the side-swing angle.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] Compared with the traditional large-area target decomposition planning method, in order to solve the problems of low data acquisition efficiency and low regional coverage efficiency caused by cloud cover, the remote sensing satellite large-area shooting planning method based on cloud map proposed in the present invention dynamically decomposes the large area according to the cloud cover information of each transit window, that is, the cloud map, and accurately plans the shooting strips of each transit window using the predicted regional cloud map, effective data base map and other reference information, and selects the preferred shooting strips with better imaging conditions, thereby improving the single data acquisition success rate and overall regional coverage efficiency of satellite shooting of large-area targets, and effectively reducing the waste of satellite imaging resources, fully meeting the planning of remote sensing satellite shooting tasks for large-area needs. The data efficiency of the shooting tasks planned by this planning method can reach 65% on average, which is significantly higher than the traditional regional pre-decomposition method that ignores cloud cover, and the overall coverage efficiency of large areas is also significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of a process flow of a cloud map-based remote sensing satellite large-area photography planning method provided in an embodiment of the present invention;

[0015] Figure 2 It is a schematic diagram of the original large-area target range and the unphotographed range;

[0016] Figure 3 Schematic diagram of the satellite's ground track and photographic range. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0018] In one embodiment, if Figure 1 As shown, the present invention provides a remote sensing satellite large-area shooting planning method based on cloud images, the method comprising the following steps:

[0019] Step 1: Update the uncaptured area and set planning conditions

[0020] In this step, the original large-area target range is first determined, and then the unphotographed range is determined based on the original large-area target range and the data coverage that has been effectively acquired. The unphotographed range of the large-area target is updated as the input object of the large-area shooting plan, and the original large-area target range and the unphotographed range are synchronously displayed on the two-dimensional map. Planning conditions are set according to specific planning business requirements, where planning conditions include planning period, satellite resources, and side swing angle restrictions.

[0021] Step 2: Load satellite tracks and generate a display of the satellite's shooting range

[0022] In this step, the satellite trajectory is loaded, the shooting range of the satellite is calculated, and the shooting range and the satellite ground trajectory are displayed on a two-dimensional map.

[0023] Optionally, step 2 specifically includes the following steps:

[0024] Step 21: Satellite orbit prediction

[0025] Taking the satellite's instantaneous orbital elements as input, the satellite's perturbation force model is constructed, the satellite motion equation is established, and the satellite's position and velocity are predicted using the numerical integration method. The core idea is to calculate the velocity by integrating the acceleration, and the position by integrating the velocity, and finally obtain the satellite orbit prediction result. The satellite perturbation force model includes the earth's gravity, the sun's and the moon's gravity, atmospheric drag, and solar pressure, etc., which can meet the accuracy requirements of services such as target visible window calculation.

[0026] Step 22: Calculation of large area transit window and photographable range

[0027] Based on the satellite orbit prediction results, that is, the position and speed of the satellite at any time during the planning period, the satellite's transit window over the original large-area target range is calculated, and the photographic range corresponding to the transit window is calculated based on the side swing angle limit and the field of view of the satellite payload. The photographic range is a strip area with the corresponding satellite ground track as the center line.

[0028] Step 23: Display satellite ground tracks and imageable range

[0029] According to the calculation results of the satellite's photographable range for a large area, the ground track of the satellite during the period of time when it passes through the original large area target range and the strip area of ​​the photographable range are displayed on a two-dimensional map.

[0030] Step 3: Select the preferred shooting strip

[0031] In this step, the preferred shooting strip is selected based on the cloud map, the shootable range and the unshootable range corresponding to the transit window.

[0032] Optionally, step three specifically includes the following steps:

[0033] Step 31: Select a transit window;

[0034] For a larger area, the satellite may pass over it more than once in a day. According to actual application requirements, a transit window is selected from multiple transit windows, and the selected transit window is used for subsequent operations such as shooting strip optimization.

[0035] Step 32: Load the cloud map showing the transit window time

[0036] The basic data source used for cloud cover forecast in this embodiment is the NC file provided by the Numerical Forecast Center of the China Meteorological Administration, which can forecast the cloud cover conditions of any location in the world in the next few days. A cloud map of the global scope is formed by the calculated cloud cover during the transit window time, the cloud map corresponding to the transit window is loaded, and the loaded cloud map is displayed on the two-dimensional map.

[0037] Step 33: Select the best shooting strip for this transit window

[0038] Combined with the cloud map displayed on the two-dimensional map, the base map of the photographable range and the uncovered range, etc., select the preferred shooting strip, which has small cloud cover and large uncovered area. Within the photographable range of the selected transit window, click on the map to select the center point of the strip to be photographed. The background of the satellite mission planning system will automatically pick up the latitude and longitude information of the location on the map, and quickly calculate the satellite's precise visible window and side swing angle for the point.

[0039] Step 4: Fine-tune the optimal shooting strip and arrange the shooting tasks accordingly

[0040] After the preferred shooting strip is basically determined, the length and precise position of the strip can be fine-tuned by fine-tuning the shooting time and swing angle of the preferred shooting strip. After the fine-tuning is completed, specific shooting requirements are created and shooting tasks are generated based on the precise visible window information, shooting time and swing angle of the fine-tuned preferred shooting strip.

[0041] Compared with the traditional large-area target decomposition planning method, in order to solve the problems of low data acquisition efficiency and low regional coverage efficiency caused by cloud cover, the remote sensing satellite large-area shooting planning method based on cloud map proposed in this embodiment dynamically decomposes the large area according to the cloud cover information of each transit window, that is, the cloud map, and accurately plans the shooting strips of each transit window using the predicted regional cloud map, effective data base map and other reference information, and selects the preferred shooting strips with better imaging conditions, thereby improving the single data acquisition success rate and overall regional coverage efficiency of the satellite shooting of large-area targets, and effectively reducing the waste of satellite imaging resources, fully meeting the planning of remote sensing satellite shooting tasks for large-area needs. The data efficiency of the shooting tasks planned by this planning method can reach 65% on average, which is significantly higher than the traditional regional pre-decomposition method that ignores cloud cover, and the overall coverage efficiency of large areas is also significantly improved.

[0042] The following is an application example of the cloud map-based large-area shooting planning method for remote sensing satellites of the present invention in actual mission planning of satellites.

[0043] Step 1: Update the uncaptured area of ​​the target area and set the planning conditions

[0044] Select "Spectrum Star Global Map Africa Region" ( Figure 2The area within the dotted box is an implementation example. Figure 2 As shown, the original large-area target range is the land area of ​​Africa, i.e. Figure 2 The area within the solid line frame is the white area within the solid line frame, which is the data coverage area that has been effectively acquired, and the remaining black area is the uncaptured area.

[0045] The planning period is set from 5:00 on July 6, 2021 to 5:00 on July 7, 2021. The satellite resources selected are Jilin-1 Spectrum 01 and Spectrum 02. The side swing angle is limited to 15 degrees, the default imaging duration is set to 100 seconds, and the side swing interval is set to 0.05 degrees.

[0046] Step 2: Load satellite tracks and generate a display showing the satellite's shooting range

[0047] Step 2.1 Satellite orbit prediction:

[0048] Taking the orbital elements of Spectrum 01 and Spectrum 02 on July 5, 2021 as input, orbit prediction extrapolation is performed to obtain the position, speed and other data of the two satellites on July 6 and July 7, and the satellite orbit prediction results are obtained. The satellite orbit prediction results are used to calculate the satellite's transit window over a large area.

[0049] Step 2.2 Calculation of large area transit window and photographable range:

[0050] According to the satellite orbit prediction results, that is, the position and speed of the satellite at any time during the planning period, the satellite's transit over a large area is calculated. The two satellites pass through a large area with a total of 4 transit windows. The photographable range corresponding to the transit window is calculated based on the maximum side swing angle and the field of view of the satellite payload. The photographable range is a strip area with the satellite ground track as the center line.

[0051] Step 2.3 displays the satellite ground track and the shooting range:

[0052] The ground track of the satellite during the period of time when it is over a large area and the bar area of ​​the shooting range are displayed on a two-dimensional map. Figure 3 As shown, if the four strip areas are marked 1 to 4 from right to left, strip areas 1 to 4 correspond to four transit windows respectively, the satellite corresponding to strip areas 2 and 4 is Spectrum 01, and the satellite corresponding to strip areas 1 and 3 is Spectrum 02.

[0053] Step 3: Select the preferred shooting strip

[0054] Step 3.1 Select one of the multiple transit windows to operate:

[0055] Select strip area 2 from the four transit windows for subsequent operations such as shooting strip optimization. The time interval of the window is from 18:25:07 to 18:49:30 on July 6.

[0056] Step 3.2 Load the cloud map showing the transit window time:

[0057] The cloud cover values ​​of the global location at 18:30:00 near the transit window time are calculated and presented as cloud cover percentages, which are divided into ten levels. According to the predicted cloud cover values ​​and corresponding levels in each longitude and latitude grid, a cloud cover heat map that can be displayed intuitively is formed, referred to as a cloud map. The cloud map is superimposed on a two-dimensional map, and different colors represent different cloud amounts. For example, blue indicates less cloud cover, which is conducive to data shooting, and reddish brown indicates more cloud cover, which is not conducive to data shooting.

[0058] Step 3.3: Optimize the shooting strip of this transit window:

[0059] Combined with the cloud information, the shooting range information and the unshot area information displayed on the map, the shooting strip with small cloud cover and large area data is selected as the preferred shooting strip. The longitude and latitude of the center point of the preferred shooting strip are (21.480, 23.906). The satellite mission planning system automatically calculates the satellite's precise visible window and side swing angle for this point. The visible time is 18:36:01, the side swing angle is -8.79 degrees, and the shooting time is 100 seconds.

[0060] Step 4: Fine-tune the optimal shooting strip and arrange the shooting tasks accordingly

[0061] After the preferred shooting strip is basically determined, the shooting time and the side swing angle can be fine-tuned. Since the cloud cover in the area before and after the strip is also small, the shooting time is extended to 130 seconds, and the side swing angle does not need to be adjusted. Finally, add shooting requirements and arrange satellite shooting tasks based on the detailed information of the preferred shooting strip.

[0062] After the satellite shooting mission is planned, the satellite performs imaging and data transmission tasks according to the instructions. The ground station receives the raw data transmitted by the satellite and transmits it back to the satellite data center, which processes the data. In the shooting results of this mission, among the 31 scenes of product data, only 2 scenes have a cloud cover of more than 20%, and the overall cloud cover of all data accounts for about 5%. The overall efficiency of the data shot in this mission is about 95%, achieving the expected effect of the planning method of the present invention.

[0063] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A cloud map-based remote sensing satellite large-area shooting planning method, characterized in that: The following steps are involved: Step 1: determining an original large-area target range and an unphotographed range, and synchronously displaying the original large-area target range and the unphotographed range on a two-dimensional map, and setting planning conditions, wherein the planning conditions include a planning period, satellite resources, and a side swing angle limit; Step 2: loading satellite tracks, calculating the shooting range of the satellite, and displaying the shooting range and the satellite ground track on the two-dimensional map; The step 2 comprises the following steps: Step 21: Satellite orbit prediction Taking the satellite's instantaneous orbital elements as input, the satellite's perturbation model is constructed to establish the satellite motion equation, and the satellite's position and velocity are predicted using the numerical integration method to obtain the satellite orbit prediction result. Step 22: Calculation of large area transit window and photographable range Calculating a satellite transit window for the original large-area target range according to the satellite orbit prediction result, and calculating a photographable range corresponding to the transit window according to the side swing angle limit and the field of view of the satellite payload, wherein the photographable range is a strip area with the corresponding satellite ground track as the center line; Step 23: Display satellite ground tracks and imageable range According to the calculation result of the photographable range, the ground track of the satellite during the period of time when it passes through the original large-area target range and the strip area of ​​the photographable range are displayed on the two-dimensional map; Step 3: selecting a preferred shooting strip according to the cloud map corresponding to the transit window, the shootable range and the unshootable range; The step three comprises the following steps: Step 31: Select a transit window; Step 32: loading a cloud map corresponding to the transit window, and displaying the cloud map on the two-dimensional map; Step 33: selecting a preferred shooting strip in combination with the cloud image, the shootable range and the uncovered range displayed on the two-dimensional map, wherein the preferred shooting strip has a small cloud amount and a large uncovered range; Step 4: fine-tune the shooting duration and the side-swing angle of the preferred shooting strip, and generate a shooting task according to the precise visible window information of the fine-tuned preferred shooting strip, the shooting duration and the side-swing angle.

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