Four-quadrant layered satellite selection method considering Beidou satellite orbit type

Abstract

The invention relates to a four-quadrant hierarchical satellite selection method considering the orbit type of Beidou satellites, and the method comprises the steps: carrying out the classification and weight determination of GEO, IGSO and MEO according to the orbit type of each Beidou satellite, and calculating a comprehensive weight through integrating the elevating angle and signal-to-noise ratio of each satellite; in order to obtain a good geometric configuration, a zenith area of a receiver is divided into 12 areas according to quadrant layering and an elevation angle and an azimuth angle, and a satellite with the maximum weight is selected from each area; if no satellites exist in a certain area or multiple satellites with the same weight exist in the certain area, the satellite closest to the center point of the area is selected from the remaining satellites in the same layer according to the minimum distance principle. According to the method, for a single Beidou system, the weight of each satellite is finely and comprehensively considered, a good geometric configuration is established, a low DOP value is achieved, on the premise that the positioning precision is guaranteed, a proper Beidou satellite is selected to participate in data processing, the positioning calculation data processing efficiency is improved, and communication resource occupation is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of satellite navigation and positioning, and in particular relates to a four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites. Background Art

[0002] The BeiDou satellite navigation system is a satellite navigation system independently built and operated by my country. With the completion of the BeiDou-3 project, the global networking of BeiDou satellites will be realized in 2020, providing high-precision positioning, navigation and timing services for global users, and playing an important role in transportation, urban construction, disaster relief and reduction. In recent years, with the successive launch and networking of BeiDou satellites, the number of available satellites in the sky has increased significantly, and the contribution of the number of satellites to the improvement of positioning accuracy has become smaller and smaller, while the corresponding data processing has occupied a large increase in computing resources; in the military field, RTK base stations that provide high-precision positioning services usually rely on radio stations to broadcast RTK differential data. Due to the performance of radio stations, there are strict restrictions on the size of the broadcast differential data. Therefore, in a battlefield environment with limited communication resources and high requirements for data processing efficiency, how to effectively improve the efficiency of satellite data processing while ensuring positioning accuracy has become an important issue facing rapid and high-precision positioning in battlefield environments.

[0003] In the process of satellite positioning solution, it is necessary to list observation equations according to the number of visible satellites and perform a large number of matrix operations, which takes up a lot of computing resources. At the same time, the RTK differential data content contains information such as pseudorange and carrier phase of each visible satellite. The more satellites are transmitted, the more communication resources are occupied. Therefore, the problem of fast and high-precision positioning in battlefield environments can be effectively solved by reducing the number of satellites involved in the solution. At present, the commonly used satellite selection strategies are mainly the following: (1) Satellite signal quality-based satellite selection method. This method usually takes the signal-to-noise ratio and signal strength of the satellite signal as the main reference, and selects satellites with high strength and high signal-to-noise ratio to participate in positioning. If this method is used alone, it is easy to cause difficulty in selecting satellites in areas with poor observation conditions such as cities and canyons, and it is impossible to select effective satellites; (2) Satellite selection method based on geometric distribution. This method first calculates the satellite altitude and azimuth above the observation station, calculates the satellite geometric precision (GDOP), and selects a group of satellite combinations with the best geometric configuration. At present, this method has been widely studied. Different satellite spatial distribution and number of satellites have a great impact on positioning. In particular, this method ignores other important factors such as signal quality, which sometimes leads to a decrease in positioning accuracy. (3) The satellite selection method based on intelligent algorithms uses emerging machine learning, artificial intelligence and other intelligent methods to train models, predict the positioning performance of different satellite combinations, and select the optimal satellite combination. This method requires a large amount of training data and computing resources, and the quality of the model is greatly affected by factors such as data quality and algorithm selection. The overall performance is not reliable enough. Summary of the invention

[0004] The present invention provides a four-quadrant hierarchical satellite selection method taking into account the orbit types of Beidou satellites. The technical problem to be solved is: solving the problem that a large number of satellites involved in positioning and solving in a battlefield environment occupy more limited data processing resources and communication resources, and the existing solution cannot comprehensively consider the weights and geometric configurations of different satellites, and cannot effectively use satellite information to select appropriate satellites to participate in positioning, while taking into account the different orbit types of Beidou satellites and the large difference in orbit accuracy.

[0005] In order to solve the above technical problems, the present invention provides 1. A four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites, characterized in that the specific steps are as follows:

[0006] Step 1: Calculate the satellite's azimuth, altitude, and signal-to-noise ratio information based on the satellite ephemeris;

[0007] Step 2: Calculate the satellite comprehensive weight according to the satellite orbit type, altitude angle and signal-to-noise ratio;

[0008] Step 3, dividing the receiver zenith area into quadrants and layers according to the azimuth and altitude;

[0009] Step 4: Select the satellite with the largest weight in each small area;

[0010] Step 5: Mark the selected satellites.

[0011] Furthermore, step 1 specifically includes receiving satellite signals and ephemeris information for initial single-point positioning, and calculating the initial position of the receiver and the position, altitude angle, azimuth angle, and signal-to-noise ratio information of the satellite.

[0012] Furthermore, in step 2, the weight ratio is determined according to the satellite orbit type; then the altitude angle weight of each satellite is calculated according to the altitude angle; then the signal-to-noise ratio weight is calculated according to the signal-to-noise ratio information; finally, the final comprehensive weight is calculated by integrating the orbit weight ratio, altitude angle weight, and signal-to-noise ratio weight.

[0013] Furthermore, the orbit weight ratio is determined according to the satellite GEO, IGSO, and MEO orbit types.

[0014] Furthermore, in step 3, the receiver zenith area is divided into three layers according to the altitude angle, and then each layer is divided into four quadrants, and the entire zenith area is divided into 12 star selection areas.

[0015] Furthermore, in step 3, the receiver zenith area is divided into three layers according to the altitude angles above 60°, 30° to 60°, and below 30°.

[0016] Furthermore, in step 4, the first round of satellite selection is performed in each region, and a satellite with the largest weight is selected in each region; if there are multiple satellites with the same weight in some regions, the distances of these satellites from the center point of the region are calculated according to the principle of minimum distance, and the satellite with the closest distance is selected.

[0017] Furthermore, if there is no valid satellite in the area, after the first round of satellite selection, a satellite with a better comprehensive distance and weight is selected from the remaining satellites in the nearby area for replacement until a satellite is selected in all areas.

[0018] Furthermore, the marked satellites are used for subsequent positioning solutions and calculation of enhanced information, while the unselected satellites are eliminated and do not participate in data solutions to reduce the amount of calculation.

[0019] Furthermore, when the current number of satellites does not exceed 12, the positioning solution is directly performed without performing satellite selection.

[0020] Beneficial effect: The present invention solves the problem that more visible satellites will reduce data processing efficiency and occupy more communication resources under the condition of limited communication resources and data processing resources in battlefield environment. At the same time, taking into account the different orbit types of Beidou satellites and the large difference in orbit accuracy, the present invention first performs initial single-point positioning to calculate the initial position of the receiver and the altitude angle, azimuth, signal-to-noise ratio and other information of the satellite; then, the weight ratio is determined according to the satellite orbit type GEO, IGSO, and MEO, and then the altitude angle weight of each satellite is calculated according to the altitude angle; considering that the observation quality of high-altitude angle satellites may not be very high due to satellite obstruction and ground reflection during actual use, the signal-to-noise ratio information is then calculated. Signal-to-noise ratio weight; finally, the final comprehensive weight is calculated by integrating the orbit weight ratio, altitude weight, and signal-to-noise ratio weight; in order to obtain a good geometric configuration, the receiver zenith area is divided into 12 areas according to the altitude and azimuth according to the quadrant; then the first round of satellite selection is carried out area by area, and a satellite with the largest weight is selected in each area; if there are multiple satellites with the same weight in some areas, the distances of these satellites from the center point of the area are calculated according to the principle of minimum distance, and the satellite with the closest distance is selected; for some areas where there are no valid satellites, the second round of satellite selection is carried out among the remaining satellites after the first round of satellite selection, and alternative satellites are selected in adjacent areas according to the distance from the center point of the area and the weight. Finally, the selected satellites are marked for subsequent positioning solution, calculation of enhanced information, etc.

[0021] The present invention comprehensively considers the influence of various factors such as the satellite's geometric configuration, signal quality, satellite orbit type, etc. through refined weighted processing, has high reliability, and is suitable for various application scenarios.

[0022] Taking into account the satellite's orbit type, altitude angle, and signal-to-noise ratio information, a refined comprehensive weighting is adopted to avoid the lack of pertinence of a single weighting method for various application scenarios. In order to obtain a good geometric configuration, the receiver zenith area is divided into 12 areas according to the altitude angle and azimuth angle according to the quadrant, and a satellite with the largest weight is selected in each area. At the same time, the weight and geometric configuration of the satellite are comprehensively considered, which can not only effectively select suitable satellites, but also reduce the loss of positioning accuracy caused by the reduction in the number of satellites. Finally, under the premise of ensuring positioning accuracy, by selecting suitable Beidou satellites to participate in data processing, the efficiency of positioning solution data processing is improved and the occupation of communication resources is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the Beidou satellite comprehensive selection process diagram

[0024] Figure 2 It is a data processing flow chart of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below.

[0026] The present invention proposes a four-quadrant hierarchical satellite selection method that takes into account the orbit type of Beidou satellites. In view of the problem that more visible satellites reduce data processing efficiency and occupy more communication resources under the condition of limited communication resources and data processing resources in battlefield environments, a four-quadrant hierarchical satellite selection method that takes into account the orbit type of Beidou satellites is proposed. The method comprehensively considers the orbit type, altitude angle, azimuth angle and signal-to-noise ratio information of Beidou satellites, selects appropriate Beidou satellites to participate in data processing, improves the positioning solution data processing efficiency, and reduces the occupation of communication resources. Specifically, it includes the following steps:

[0027] Step 1) First, receive satellite signals and ephemeris information for initial single-point positioning, calculate the receiver's initial position and the satellite's position, altitude, azimuth, signal-to-noise ratio, and other information;

[0028] Step 2) Determine the weight ratio according to the satellite orbit type; then calculate the altitude angle weight of each satellite according to the altitude angle; then calculate the signal-to-noise ratio weight according to the signal-to-noise ratio information; finally, calculate the final comprehensive weight by integrating the orbit weight ratio, altitude angle weight, and signal-to-noise ratio weight;

[0029] Specifically, the satellite's orbit type, altitude angle, azimuth angle, signal-to-noise ratio and other information are fully considered to calculate the comprehensive weight, so as to avoid the lack of pertinence of a single weighting method for various application scenarios. First, the orbit weight ratio is determined according to the satellite GEO, IGSO, and MEO orbit types, and then the altitude angle weight of each satellite is calculated according to the altitude angle; considering that in actual use, the observation quality of high-altitude angle satellites may not be very high due to satellite obstruction and ground reflection, the signal-to-noise ratio weight is calculated based on the signal-to-noise ratio information; finally, the final comprehensive weight is calculated by combining the orbit weight ratio, altitude angle weight, and signal-to-noise ratio weight;

[0030] Step 3), dividing the receiver zenith area into quadrants and layers according to the azimuth and altitude;

[0031] Furthermore, the receiver zenith area is divided into three layers according to the altitude angle above 60°, 30° to 60°, and below 30°, and then each layer is divided into four quadrants. The entire zenith area is divided into 12 star selection areas in total.

[0032] Step 4) Select the satellite with the largest weight in each area: If there are satellites with the same weight in the area, select the satellite closest to the center of the area; if there is no valid satellite in the area, select the satellite with better distance and weight from the remaining satellites in the nearby area after the first round of satellite selection.

[0033] Specifically, in order to obtain a good geometric configuration, the receiver zenith area is divided into 12 areas according to the quadrants based on the altitude angle and azimuth angle;

[0034] Then the first round of satellite selection is carried out in each area, and a satellite with the largest weight is selected in each area; if there are multiple satellites with the same weight in some areas, the distances of these satellites from the center point of the area are calculated according to the principle of minimum distance, and the satellite with the closest distance is selected; if there are no valid satellites in some areas, the second round of satellite selection is carried out among the remaining satellites after the first round of satellite selection, and replacement satellites are selected in adjacent areas according to the distance from the center point of the area and the weight.

[0035] The satellite selection process is completed until a satellite is selected in all areas.

[0036] Step 5: Finally, the selected satellites are marked for subsequent positioning and calculation of differential correction parameter information, etc. The unselected satellites are removed and do not participate in data calculation to reduce the amount of calculation.

[0037] Example: Figure 2 The data processing flow of the star selection of the present invention is shown as follows:

[0038] Step 1: Receive satellite signals and ephemeris information for initial single-point positioning, and calculate the receiver's initial position and the satellite's position, altitude, azimuth, signal-to-noise ratio, and other information;

[0039] Step 2: Determine the current number of satellites. If the number does not exceed 12, the positioning solution is performed directly without selecting satellites. If the number of satellites exceeds 12, the satellite selection strategy is executed.

[0040] Step 3: Determine the orbit weight ratio according to the satellite orbit type GEO, IGSO, and MEO, and then calculate the altitude angle weight of each satellite according to the altitude angle; Considering that the observation quality of high-altitude angle satellites may not be very high due to satellite obstruction and ground reflection in actual use, the signal-to-noise ratio weight is calculated based on the signal-to-noise ratio information; finally, the final comprehensive weight is calculated by integrating the orbit weight ratio, altitude angle weight, and signal-to-noise ratio weight;

[0041] Step 4: divide the zenith area into three layers: above 60°, 30° to 60°, and below 30°. Then divide each layer into four quadrants. The entire zenith area is divided into 12 star selection areas.

[0042] Step 5, then the first round of satellite selection is carried out area by area, and a satellite with the largest weight is selected in each area; if there are multiple satellites with the same weight in some areas, the distances of these satellites from the center point of the area are calculated according to the principle of minimum distance, and the satellite with the closest distance is selected; if there are no valid satellites in some areas, a second round of satellite selection is carried out among the remaining satellites after the first round of satellite selection, and a replacement satellite is selected in each adjacent area according to the distance from the center point of the area and the weight; until a satellite is selected in all areas, the satellite selection process is completed.

[0043] Step 6: Mark the selected satellites for subsequent positioning and calculation of differential correction parameter information, etc. Unselected satellites are removed and do not participate in data calculation to reduce the amount of calculation.

[0044] In summary, under the condition of limited communication resources and data processing resources in battlefield environment, there are problems such as reduced data processing efficiency and more communication resources occupied due to more visible satellites. The existing selection method does not make comprehensive use of satellite information and satellite geometric configuration, resulting in a decrease in positioning accuracy after satellite selection. This method targets the single Beidou system, which not only comprehensively considers the weight of each satellite, but also establishes a good geometric configuration and has a lower DOP value.

[0045] The present invention aims at the weight problem of each satellite in the star selection process. In the star selection process, the weight is first determined according to the orbit type of each Beidou satellite, according to GEO, IGSO, and MEO classification, and then the altitude angle and signal-to-noise ratio of each satellite are comprehensively calculated to calculate the comprehensive weight. In order to obtain a good geometric configuration, the zenith area of ​​the receiver is divided into 12 areas according to the altitude angle and azimuth according to the quadrant, and a satellite with the largest weight is selected from each area; if there is no satellite in a certain area or there are multiple satellites with the same weight, according to the minimum distance principle, the satellite closest to the center point of the area is selected from the remaining satellites in the same layer.

[0046] This method targets a single BeiDou system. It not only comprehensively considers the weight of each satellite, but also establishes a good geometric configuration with a lower DOP value. Under the premise of ensuring positioning accuracy, it selects appropriate BeiDou satellites to participate in data processing, thereby improving the efficiency of positioning solution data processing and reducing the occupation of communication resources.

[0047] Aiming at the problems of reduced data processing efficiency and more communication resource occupation caused by more visible satellites under the condition of limited communication resources and data processing resources in battlefield environment, the present invention proposes a four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellite, comprehensively considers the orbit type, altitude angle, azimuth angle and signal-to-noise ratio information of Beidou satellite, selects appropriate Beidou satellite to participate in data processing, improves the positioning solution data processing efficiency, and reduces the communication resource occupation.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites, characterized in that: The specific steps are as follows: Step 1: Calculate the satellite's azimuth, altitude, and signal-to-noise ratio information based on the satellite ephemeris; Step 2: Calculate the satellite comprehensive weight according to the satellite orbit type, altitude angle and signal-to-noise ratio; Step 3, dividing the receiver zenith area into quadrants and layers according to the azimuth and altitude; Step 4: Select the satellite with the largest weight in each small area; Step 5: Mark the selected satellites.

2. A four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites according to claim 1, characterized in that: Step 1 specifically includes receiving satellite signals and ephemeris information for initial single-point positioning, and calculating the initial position of the receiver and the position, altitude angle, azimuth angle, and signal-to-noise ratio information of the satellite.

3. A four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites according to claim 1, characterized in that: In step 2, the weight ratio is determined according to the satellite orbit type; then the altitude angle weight of each satellite is calculated according to the altitude angle; and then the signal-to-noise ratio weight is calculated according to the signal-to-noise ratio information; Finally, the final comprehensive weight is calculated by integrating the orbit weight ratio, altitude angle weight, and signal-to-noise ratio weight.

4. A four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites according to claim 3, characterized in that: The orbit weight ratio is determined according to the satellite GEO, IGSO, and MEO orbit types.

5. A four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites according to claim 1, characterized in that: In step 3, the receiver zenith area is divided into three layers according to the altitude angle, and then each layer is divided into four quadrants. The entire zenith area is divided into 12 star selection areas.

6. A four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites according to claim 5, characterized in that: In step 3, the receiver zenith area is divided into three layers according to the altitude angles above 60°, 30° to 60°, and below 30°.

7. A four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites according to claim 1, characterized in that: In step 4, the first round of satellite selection is performed in each region, and a satellite with the largest weight is selected in each region; if there are multiple satellites with the same weight in some regions, the distances of these satellites from the center point of the region are calculated according to the principle of minimum distance, and the satellite with the closest distance is selected.

8. A four-quadrant hierarchical satellite selection method taking into account the orbit type of Beidou satellites according to claim 7, characterized in that: If there is no valid satellite in the area, after the first round of satellite selection, a satellite with a better distance and weight will be selected from the remaining satellites in the nearby area to replace it until a satellite is selected in all areas.

9. The four-quadrant hierarchical satellite selection method according to claim 1, characterized in that: The marked satellites are used for subsequent positioning solutions and calculation of enhanced information. The unselected satellites are eliminated and do not participate in data solutions to reduce the amount of calculation.

10. The four-quadrant hierarchical satellite selection method according to claim 1, characterized in that: When the current number of satellites does not exceed 12, the positioning solution is performed directly without performing satellite selection.

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