Method for establishing whole-month navigation troille library based on regional partitioning and layering

Abstract

The invention discloses a method for establishing a whole-moon navigation troille library based on regional blocking and layering. The method comprises the following steps: carrying out regional division on the moon according to longitude and latitude; according to the longitude and latitude range corresponding to each falling pit, the basic falling pit library is partitioned; according to the usable rail height range of each falling pit, the foundation falling pit warehouse is layered; and carrying out secondary screening on the basic troille library to generate the whole-month navigation troille library. The use method of the full-moon navigation troille library comprises the following steps: determining the position of an image surface on the lunar surface according to the orbit height and a priori position attitude; according to the orbit height, screening out a target orbit height layer and an available falling pit data set corresponding to the target area from the whole-month navigation falling pit library; and carrying out navigation operation by taking the holes in the available hole data set as a reference. Therefore, the problem that all the holes cannot be directly used for navigation due to limited on-satellite computing power and limited navigation efficiency is solved, and the method can be applied to lunar navigation, lunar landing navigation and other deep space exploration navigation tasks.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of a full-moon crater library, in particular to a full-moon navigation crater library establishment method based on regional blocking and layering. BACKGROUND

[0002] Craters are common surface fixed features of extraterrestrial celestial bodies. In the process of a spacecraft flying around a celestial body, craters can be regarded as an optical image feature or a landmark for real-time position and attitude estimation of the spacecraft. However, for large extraterrestrial celestial bodies such as the moon and Mars, although there are public crater data sets, due to the excessive number of craters, for example, there are more than 1.2 million craters with a diameter of 1 km or more in the Robbins full-moon crater library. Therefore, when all the crater data is directly used in the navigation process, the hardware capacity is seriously insufficient, or the solution is too slow, which seriously affects the navigation efficiency. SUMMARY

[0003] The application provides a full-moon navigation crater library establishment method based on regional blocking and layering. The full-moon navigation crater library established by the application can quickly find navigation craters in the corresponding region and layer according to the coarse position of the spacecraft during spacecraft navigation, greatly improving the matching and solving efficiency of the algorithm, and realizing rapid crater navigation.

[0004] In a first aspect, a full-moon navigation crater library establishment method based on regional blocking and layering is provided, comprising:

[0005] Dividing the moon into regions according to longitude and latitude;

[0006] Dividing the basic crater library into zones according to the longitude and latitude range of each crater;

[0007] Dividing the basic crater library into layers according to the usable orbital height range of each crater;

[0008] Performing secondary screening on the basic crater library to generate a full-moon navigation crater library.

[0009] In combination with the first aspect, in some implementations of the first aspect, the moon is divided into regions, satisfying:

[0010] The moon is divided into regions using a cylindrical projection method in the middle and low latitude areas of the moon, and using a polar projection method in the high latitude areas of the moon; adjacent two regions overlap with each other; the side length of the region is the same.

[0011] In combination with the first aspect, in some implementations of the first aspect, the establishment method of the basic crater library comprises:

[0012] Selecting multiple craters with a diameter not less than a preset size from a full-set moon crater data set to establish a basic crater library.

[0013] With reference to the first aspect, in some implementations of the first aspect, the partitioning of the basic crater library comprises:

[0014] The relevant information of each crater in the basic crater library is put into the information group of the corresponding partition, and the area number of each crater is identified, so as to complete the partitioning operation of the basic crater library.

[0015] With reference to the first aspect, in some implementations of the first aspect, determining the usable orbit height range of the crater comprises:

[0016] The center of the crater is projected onto the lunar surface elevation model DEM, and the usable orbit height range of the crater is obtained according to the sensor parameters, and the usable orbit height of the crater satisfies that the probability of being detected is higher than a preset probability in the usable orbit height range.

[0017] With reference to the first aspect, in some implementations of the first aspect, the layering of the basic crater library comprises:

[0018] According to the orbit height of the spacecraft in the crater navigation process, the craters in the basic crater library are layered;

[0019] According to the usable orbit height range of each crater in the basic crater library, the relevant information of each crater is put into the information group of the corresponding orbit height layer, and the orbit height layer number of each crater is identified, so as to complete the layering operation of the basic crater library.

[0020] With reference to the first aspect, in some implementations of the first aspect, the secondary screening criteria comprise at least one of the following:

[0021] Selecting craters with shapes close to circles and clear edges;

[0022] The craters are uniformly distributed in the area, and there is no nesting, intersection or tangency;

[0023] In combination with the crater navigation algorithm, the craters stably extracted and matched by the navigation algorithm are retained.

[0024] With reference to the first aspect, in some implementations of the first aspect, the relevant information of the craters in the full-moon navigation crater library comprises: area number, crater serial number, center point longitude, center point latitude, crater diameter, center point elevation, maximum usable height, and minimum usable height.

[0025] Secondly, a use method of a full-moon navigation crater library is provided, wherein the full-moon navigation crater library is obtained by the method according to any one of the implementations of the first aspect; and the use method comprises:

[0026] According to the orbit height and the prior position and attitude, the position of the image plane on the lunar surface is determined.

[0027] According to the orbit height, a first crater set corresponding to the target orbit height layer is screened from the full moon navigation crater library, and according to the position of the image plane on the moon surface, a second crater set corresponding to the target area is screened from the full moon navigation crater library, and the intersection of the first crater set and the second crater set is used as a usable crater data set.

[0028] The crater in the usable crater data set is used as a reference for navigation operation.

[0029] In a third aspect, an electronic device is provided, which is configured to execute the method as described in any one of the implementation manners of the first aspect to the second aspect.

[0030] Compared with the prior art, the scheme provided in the present application has at least the following beneficial technical effects:

[0031] The method solves the problem that the moon surface has too many craters, and all the craters cannot be directly used for navigation due to the limitation of on-board computing power and navigation efficiency. The method can be applied to tasks such as moon orbit navigation and moon landing navigation, and can be extended to navigation tasks of other deep space exploration. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a schematic diagram for middle-low latitude grid division.

[0033] Figure 2 It is a schematic diagram for polar grid division. DETAILED DESCRIPTION

[0034] The present application will be further described in detail below with reference to the drawings and specific embodiments.

[0035] The present application provides a full moon navigation crater library establishment method based on regional division and layering, and the specific steps are as follows.

[0036] Step 101, divide the moon according to latitude and longitude.

[0037] According to the navigation requirement, the moon is divided according to latitude and longitude. The size of each region is, for example, 400kmx400km. In some embodiments, considering the problem of moon projection, the middle-low latitude area adopts a cylindrical projection method for regional division, and the high latitude area adopts a polar projection method for regional division. The adjacent two regions can overlap with each other.

[0038] As shown in Figure 1 , the middle-low latitude -60°~+60° division region distribution is, for example, 11 rows in the north-south direction and 33 columns in the east-west direction, which ensures that the overlap degree of adjacent regions is about 2%. As shown in Figure 2As shown, the high-latitude regions above 60° and below -60° adopt polar projection mode, and the distribution of the divided regions is 5 rows in the north-south direction and 5 columns in the east-west direction, ensuring that the overlap of adjacent regions is about 1%. Finally, a total of 413 regions can be obtained for the whole month.

[0039] In step 102, a plurality of craters with a diameter not less than a preset size are selected from an existing lunar crater dataset to establish a basic crater library; and according to the longitude and latitude range corresponding to each crater, the relevant information of each crater is put into the information group of the corresponding partition, and the region number of each crater is identified, so as to complete the partition operation of the basic crater library.

[0040] The basic crater library is derived from, for example, the Robbins lunar crater public dataset. A plurality of craters with a diameter not less than 1 km are selected from the Robbins lunar crater public dataset, and the relevant information of each crater includes the longitude and latitude of the crater center, the radius, etc. Then the craters in the basic crater library corresponding to the longitude and latitude range are put into the corresponding partition and the region number is added.

[0041] In step 103, the usable orbit height range of each crater is determined.

[0042] The center of each crater in each region is projected onto the lunar surface elevation model DEM, and the elevation data corresponding to the crater center point is supplemented in the relevant information of the crater. According to the sensor parameters, the usable orbit height range of each crater in each region is determined. The usable orbit height of the crater satisfies that the probability of detecting the crater is higher than a preset probability within the usable orbit height range.

[0043] In step 104, the basic crater library is layered according to the elevation data corresponding to each crater center point.

[0044] According to the navigation range, a plurality of orbit height layers are determined, and each crater in each region is layered according to the orbit height of the vehicle in the crater navigation process. Then according to the navigation height range corresponding to each crater in the basic crater library, the relevant information of each crater is put into the information group of the corresponding orbit height layer, and the orbit height layer number of each crater is identified, so as to complete the layering operation of the basic crater library. The navigation height range corresponding to each crater can refer to that the probability of detecting the crater is higher than a preset probability within the navigation height range corresponding to the crater. Each layer of crater library corresponds to a fixed orbit height range, which ensures that a sufficient number of craters can be detected and used for navigation at any orbit height. The same crater can be assigned to different layers.

[0045] Generally, the crater detection algorithm has a certain range of adaptation to the size of the crater on the image plane. The size of the crater on the lunar surface imaged on the image plane changes with the orbit height. Therefore, according to the orbit parameters and the navigation sensor parameters, combined with the stability of the craters that can be detected at different orbit heights, the navigation height range corresponding to each crater in each region is obtained, and the craters are layered according to the navigation range, so that the number of craters participating in operation can be greatly reduced, and the algorithm efficiency is improved.

[0046] Step 105, secondary screening is performed on the basic crater library.

[0047] The secondary screening criteria include at least one of the following: selecting craters with shapes close to a circle and clear edges; the craters are uniformly distributed in the region, and there is no nesting, intersection, tangency, etc. The above secondary screening criteria are beneficial to improve the quality of the craters in the crater library.

[0048] The secondary screening criteria can also include: combining the navigation algorithm of the crater, and retaining the craters that can be stably extracted and matched by the navigation algorithm.

[0049] Step 106, after the secondary screening of the craters, the full-moon navigation crater library is generated.

[0050] Thus, the minimum envelope of the full-moon navigation crater library is established, and the subsequent navigation search efficiency is further improved.

[0051] In some embodiments, the format of the full-moon navigation crater library is shown in Table 1.

[0052] Table 1

[0053]

[0054] The project proposes a full-moon navigation crater library establishment method based on regional blocking and layering. The moon is divided into regions, and the partitioning and layering of the public crater dataset are realized according to the flight height and the visibility of the craters. The craters are screened by using the crater distribution and algorithm performance, and the full-moon navigation crater library is established, which solves the problem that the public crater dataset cannot be directly used for lunar navigation due to the limitation of on-board computing power and navigation efficiency, and greatly improves the search efficiency in the crater navigation process.

[0055] The application also provides a use method of the full-moon navigation crater library, which is obtained by the above-mentioned full-moon navigation crater library establishment method based on regional blocking and layering.

[0056] Step 201, according to the orbit height and the prior position and attitude, the position of the image plane on the lunar surface is determined.

[0057] In step 202, according to the track height, a first crater set corresponding to the target track height layer is filtered from the full moon navigation crater library, and according to the position of the image plane on the moon surface, a second crater set corresponding to the target area is filtered from the full moon navigation crater library, and the intersection of the first crater set and the second crater set is taken as the available crater data set.

[0058] In step 203, the subsequent navigation operation is performed with the craters in the available crater data set as the reference.

[0059] The method provided by the aspect can also be extended to other extraterrestrial celestial body navigation tasks, and is particularly suitable for large celestial body navigation tasks.

[0060] Although the present application is disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any possible changes and modifications made by those skilled in the art without departing from the spirit and scope of the present application shall be included in the protection scope of the present application, which shall be defined by the scope of the claims of the present application.

Claims

1. A method for establishing a full-moon navigation crater library based on regional segmentation and stratification, characterized in that: include: Divide the moon into regions according to longitude and latitude; The basic crater library is divided into zones according to the latitude and longitude ranges corresponding to each crater; The basic crater library is layered according to the range of available orbital altitudes for each crater; The basic crater library is screened a second time to generate a full-moon navigation crater library.

2. The method according to claim 1, characterized in that The above-mentioned division of the moon into regions satisfies the following requirements: The low and middle latitude regions of the moon are divided into regions using cylindrical projection, while the high latitude regions of the moon are divided into regions using polar projection. Two adjacent regions overlap with each other, and the sides of the regions have the same length.

3. The method according to claim 1, characterized in that The method for establishing the basic crater library includes: From the complete lunar crater dataset, multiple craters with diameters no less than a preset size are selected to establish a basic crater library.

4. The method according to claim 1, wherein The basic crater library is divided into two parts: The relevant information of each crater in the basic crater library is placed into the information group of the corresponding partition, and the area number of each crater is identified to complete the partition operation of the basic crater library.

5. The method according to claim 1, wherein The range of orbital altitudes available for determining craters includes: The center of the crater is projected onto the lunar surface elevation model DEM, and the usable orbital altitude range of the crater is obtained according to the sensor parameters. The usable orbital altitude of the crater satisfies that within the usable orbital altitude range, the probability of the crater being detected is higher than the preset probability.

6. The method according to claim 1, characterized in that The basic crater library is layered, including: The craters in the basic crater library are stratified according to the orbital altitude of the spacecraft during crater navigation; According to the usable orbital altitude range of each crater in the basic crater library, the relevant information of each crater is placed in the information group of the corresponding orbital altitude layer, and the orbital altitude layer number of each crater is identified to complete the layering operation of the basic crater library.

7. The method according to claim 1, characterized in that The secondary screening criteria include at least one of the following: Select craters that are nearly circular in shape and have clear edges; The craters are evenly distributed in the region, and there is no nesting, intersection, or tangency. Combined with the crater navigation algorithm, the craters stably extracted and matched by the navigation algorithm are retained.

8. The method according to claim 1, characterized in that The relevant information of craters in the full-month navigation crater library includes: area number, crater serial number, center point longitude, center point latitude, crater diameter, center point elevation, highest available altitude, and lowest available altitude.

9. A method for using the full-moon navigation crater library, characterized in that: The full-moon navigation crater library is obtained by the method according to any one of claims 1 to 8; the method of using the library comprises: Determine the position of the image plane on the lunar surface based on the orbital altitude and the prior position and attitude; According to the orbital altitude, the first crater set corresponding to the target orbital altitude layer is selected from the full-moon navigation crater library. According to the position of the image plane on the lunar surface, the second crater set corresponding to the target area is selected from the full-moon navigation crater library. The intersection of the first and second crater sets is used as the available crater dataset. Navigation operations are performed based on craters in the available crater dataset.

10. An electronic device, characterized in that: The electronic device is configured to execute the method according to any one of claims 1 to 9.

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