Beidou / GNSS Satellite Time and Space Matching Method and System Based on Angular Distance

Abstract

The present invention discloses a Beidou / GNSS satellite time and space matching method and system based on angular distance. The method includes establishing a satellite angular distance calculation model based on the elevation angle and azimuth angle, and calculating to form a numerical sequence of angular distances; based on the constructed numerical sequence of angular distances, screening the satellite pairs corresponding to the minimum angular distance one by one, and performing satellite space matching in sequence; based on the constructed numerical sequence of angular distances, calculating the average angular distance of all satellites within the selected time period; using the calculated average angular distance as the matching index of all satellites within the selected time period to perform satellite time matching. The present invention is applicable to the scenario of Beidou / GNSS satellite signal grafting, is not affected by the poor matching accuracy of a single elevation angle or azimuth angle, takes into account both satellite time and space matching, can provide rich sample data for satellite precise positioning and integrity monitoring of integrated navigation, and solves the problem of high cost in actual measurement data acquisition.

Description

Technical Field

[0001] The present invention relates to a Beidou / GNSS satellite time and space matching method and system based on angular distance. Background Art

[0002] Signal grafting is a typical hardware-in-the-loop simulation test method, which is a compromise between field tests and laboratory tests. The idea is to graft error signals onto "clean" signals so that the grafted signals can exhibit the characteristics of the error signals. The data simulation method based on signal grafting has the advantages of low cost and high data utilization rate. Typical Global Navigation Satellite System (GNSS) data simulation is realized by using a Beidou / GNSS simulator and a Record and Playback Systems (RPS). The Beidou / GNSS simulator conducts theoretical simulation of various Beidou / GNSS information, while the RPS records signals in the real environment. Both can obtain research data in the laboratory. In addition, the Beidou / GNSS data simulation can also draw on the idea of signal grafting: obtain the errors that have a greater impact on GNSS performance in complex urban environments, and graft the errors onto the Beidou / GNSS data collected in open environments or the satellite-earth distances calculated according to the coordinates of open environments, so as to achieve the purpose of simulating Beidou / GNSS data in complex urban environments.

[0003] The Beidou / GNSS positioning principle shows that the Beidou / GNSS positioning accuracy is not only related to the Beidou / GNSS observation accuracy, but also affected by the distribution of Beidou / GNSS satellites. The Beidou / GNSS receiver can simultaneously observe multiple satellites, which results in multiple satellites available for grafting in open environments and multiple errors available for grafting in complex environments. In addition, it is impossible to ensure that the lengths of the grafted data and the grafted errors are the same. Therefore, it is necessary to consider the satellite matching between the grafted errors and the grafting sources in Beidou / GNSS error grafting to solve the problems of "many-to-many" satellites and inconsistent data lengths in Beidou / GNSS error grafting. Summary of the Invention

[0004] In order to reduce the influence of satellite spatial distribution and time inconsistency on the correctness of Beidou / GNSS satellite signal grafting, the present invention considers the influence of satellite distribution on GNSS positioning, and proposes a satellite space matching method based on angular distance and a satellite time matching method based on average angular distance to select the satellites and time periods in open environments that are closest to the satellite distribution in complex environments, ensuring the accuracy of satellite matching.

[0005] According to one aspect of the specification of the present invention, there is provided a Beidou / GNSS satellite time and space matching method based on angular distance, which is applicable to the scenario of Beidou / GNSS satellite signal grafting, including:

[0006] Establish a satellite angular distance calculation model based on the elevation angle and azimuth angle, and calculate to form a sequence of angular distance values;

[0007] Based on the constructed sequence of angular distance values, screen the satellite pairs corresponding to the minimum angular distance one by one, and perform satellite spatial matching in sequence;

[0008] Based on the constructed sequence of angular distance values, calculate the average angular distance of all satellites within the selected time period;

[0009] Use the calculated average angular distance as the matching index of all satellites within the selected time period to perform satellite time matching.

[0010] The above technical solution establishes the angular distance information based on the combination of the elevation angle and azimuth angle as the satellite matching index. At the same time, the satellite matching process takes into account spatial consistency and time consistency, ensuring the continuity and correctness of the satellite movement trajectory within the time period after matching.

[0011] As a further technical solution, establish a satellite angular distance calculation model based on the elevation angle and azimuth angle, and calculate to form a sequence of angular distance values, including:

[0012] Calculate the satellite angular distance using the elevation angles and azimuth angles of two satellites, obtain the angular distance value of these two satellites at this moment, and traverse all the satellite numbers one by one to form a sequence of angular distance values between different satellites.

[0013] As a further technical solution, screen the satellite pairs corresponding to the minimum angular distance one by one, and perform satellite spatial matching in sequence, including:

[0014] Determine the satellite pair corresponding to the minimum angular distance from the constructed sequence of angular distance values between different satellites as the optimal matching result of these two satellites. At the same time, delete all the angular distance values corresponding to these two satellites in the sequence of angular distance values;

[0015] Select the minimum angular distance from the new sequence of angular distance values in sequence, and determine the satellite pair corresponding to the minimum angular distance at this time until all satellite pairs are selected, completing the satellite spatial matching.

[0016] As a further technical solution, calculate the average angular distance of all satellites within the target time period, including:

[0017] Calculate the angular distance value of the satellite pair to be matched at each moment, take the average value of the angular distance values of the satellite pair to be matched within the selected time period, and obtain the angular distance average value of the satellite pair to be matched within the selected time period;

[0018] Use the obtained satellite pairing and the angular distance average values of each satellite pair to calculate the average angular distance of all satellites within the selected time period.

[0019] As a further technical solution, satellite time matching is performed, including:

[0020] Taking the average angular distance as the matching index for all satellite pairs within the selected time period, calculating the average angular distance of satellites in multiple time periods through translation, and obtaining a numerical sequence of average angular distances in multiple time periods;

[0021] Judging the average angular distance values of satellite pairs in all time periods, and taking the time period with the smallest average angular distance value as the final result of satellite time matching to complete satellite time matching.

[0022] According to one aspect of the specification of the present invention, a Beidou / GNSS satellite time and space matching system based on angular distance is provided, which is applicable to the Beidou / GNSS satellite signal grafting scenario, including:

[0023] A satellite angular distance calculation module, which is used to establish a satellite angular distance calculation model based on the altitude angle and azimuth angle, and calculate and form a numerical sequence of angular distances;

[0024] A satellite space matching module, which is used to screen satellite pairs corresponding to the smallest angular distance one by one based on the constructed numerical sequence of angular distances, and perform satellite space matching in sequence;

[0025] A satellite average angular distance calculation module, which is used to calculate the average angular distance of all satellites within the selected time period based on the constructed numerical sequence of angular distances;

[0026] A satellite time matching module, which is used to perform satellite time matching by taking the calculated average angular distance as the matching index for all satellites within the selected time period.

[0027] According to one aspect of the specification of the present invention, a Beidou / GNSS satellite time and space matching device based on angular distance is provided, including a memory and a processor. The memory stores program instructions executed by the processor, and the processor calls the program instructions to execute the steps of the Beidou / GNSS satellite time and space matching method based on angular distance.

[0028] According to one aspect of the specification of the present invention, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium stores computer instructions, and the computer instructions cause the computer to execute the steps of the Beidou / GNSS satellite time and space matching method based on angular distance.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. The present invention aims at the grafting of Beidou / GNSS satellite signals, constructs the angular distance information between satellites based on the elevation angle and azimuth angle, and establishes the angular distance value as the evaluation index for satellite matching, so as to solve the limitation that only relying on the elevation angle or azimuth angle causes inconsistent sky distributions of satellites, and can effectively ensure the accuracy of satellite matching.

[0031] 2. When the present invention performs satellite matching, it takes into account both spatial matching and temporal matching. It not only requires that the satellite positions have good consistency at a fixed moment, but also requires that the satellite movement trajectories have good consistency within a certain time period, so as to solve the problem of jumping of matching satellites existing only through spatial matching and ensure the continuity of satellite matching results within a certain time period.

[0032] 3. The present invention uses the actually collected open environment and complex environment to verify the satellite matching performance: satellite matching can achieve better matching results with consistent sky distributions of satellites in both the data collected simultaneously in the same area and the dynamic vehicle-mounted data. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings used in the description of the embodiments or the prior art. Obviously, the following-described drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 It is a schematic flowchart of the Beidou / GNSS satellite time and space matching method based on angular distance provided by the embodiment of the present invention;

[0035] Figure 2 It is a schematic diagram of the principle of Beidou / GNSS satellite time and space matching based on angular distance provided by the embodiment of the present invention;

[0036] Figure 3 It is a schematic diagram of the angular distance of a satellite at a certain fixed moment provided by the embodiment of the present invention;

[0037] Figure 4 It is a schematic diagram of the angular distance of a satellite at different moments provided by the embodiment of the present invention;

[0038] Figure 5 It is a flowchart of satellite spatial matching based on angular distance provided by the embodiment of the present invention;

[0039] Figure 6 It is a flowchart of satellite temporal matching based on average angular distance provided by the embodiment of the present invention;

[0040] Figure 7(a)-(b) are schematic diagrams of the simulated satellite spatial matching results of the same group of data provided by the embodiments of the present invention. (a) is a sky map in an open environment, and (b) is a sky map in a complex environment;

[0041] Figure 8 (a)-(b) are schematic diagrams of the influence of the average angular distance limit on the satellite time and space matching provided by the embodiments of the present invention. (a) Without the average angular distance limit, (b) With the average angular distance limit (threshold 30°);

[0042] Figure 9 is a structural block diagram of the Beidou / GNSS satellite time and space matching system based on angular distance provided by the embodiments of the present invention. Detailed implementation manners

[0043] It should be noted that:

[0044] The azimuth and elevation angles of a satellite are often used to describe the position of the satellite in the sky. Therefore, it is reasonable to use the azimuth and elevation angles to construct an index to measure the proximity of satellites. In astronomy, angular distance is used to describe the distance between stars observed from the Earth. The angular distance is defined as the angle between the straight lines pointing from the observer to two objects when observing these two objects from a position different from the two objects (i.e., the third point). The angular distance is used as an index to measure the proximity of Beidou / GNSS satellites in the Beidou / GNSS satellite matching. In the Beidou / GNSS satellite spatial matching, the smaller the angular distance, the closer the distribution of the satellites in the sky. The distribution of Beidou / GNSS satellites is strictly bound to time. Conducting time matching is essentially still based on the spatial distribution of the satellites for selection. The spatial matching is selected with a certain moment as an example, while in the time matching, the time period data is processed, and it is necessary to calculate the angular distance at each moment within the time period to measure the proximity of the satellites within the time period.

[0045] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. In addition, the technical features in each embodiment or individual embodiment provided by the present invention can be arbitrarily combined with each other to form a new technical solution. Such combination is not restricted by the order of steps and / or the mode of structural composition, but must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0047] Please refer to Figure 1 , a Beidou / GNSS satellite time matching and space matching method based on angular distance provided by the embodiments of the present invention is applicable to the Beidou / GNSS satellite signal grafting scenario, and includes a satellite angular distance calculation sub-process, a satellite space matching sub-process, a satellite average angular distance calculation sub-process, and a satellite time matching sub-process.

[0048] Among them, the satellite angular distance calculation sub-process mainly calculates the satellite angular distance by using the elevation angle and azimuth angle of two satellites, obtains the angular distance value of these two satellites at this moment, and traverses all satellite numbers one by one to form a sequence of angular distance values between different satellites.

[0049] The satellite space matching sub-process mainly determines the satellite pair corresponding to the minimum angular distance from the angular distance value sequence as the optimal matching result of these two satellites. At the same time, all angular distance values corresponding to these two satellites are deleted from the angular distance value sequence, and the angular distance values corresponding to these two satellites no longer participate in the subsequent minimum angular distance screening process. Select the minimum angular distance from the new angular distance value sequence in turn, and determine the satellite pair corresponding to the minimum angular distance at this time until all satellite pairs are selected, and the satellite space matching is completed.

[0050] The satellite average angular distance calculation sub-process first calculates the angular distance value of the satellite pair to be matched at each moment, and then takes the average value of the angular distance values of the satellite pair within the selected time period to obtain the angular distance average value of the satellite pair within this time period. Then, using the obtained satellite pairing and the angular distance average value of each satellite pair, calculate the average angular distance of all satellites within this time period.

[0051] The satellite time matching calculation sub - process is carried out after the angular distance calculation, spatial matching, and average angular distance calculation. The average angular distance is used as the matching index for all satellite pairs during this period. By translation, the average angular distance of satellites in multiple time periods is calculated, obtaining a numerical sequence of average angular distances in multiple time periods. The average angular distance values of satellite pairs in all time periods are judged, and the time period with the smallest average angular distance value is used as the final result of satellite time matching, thus completing the satellite time matching.

[0052] In the embodiment of the present invention, the angular distance information between satellites is constructed based on the elevation angle and azimuth angle, and the angular distance value is established as the evaluation index for satellite matching; taking into account both satellite spatial matching and time matching, the angular distance evaluation is used to show that the satellite positions have good consistency at a fixed moment, and at the same time, the average angular distance evaluation is used to show that the satellite motion trajectories have good consistency within a certain time period.

[0053] Please refer to Figure 2 , the figure shows the technical principle framework of Beidou / GNSS satellite time and space matching based on angular distance provided by the embodiment of the present invention, including processes such as satellite data input to be matched, satellite angular distance calculation, satellite spatial matching and its judgment, satellite average angular distance calculation, satellite time matching and its judgment, etc.

[0054] (1) Embodiment of satellite spatial matching

[0055] The schematic diagram of the angular distance between two satellites during satellite spatial matching is shown in Figure 3 . Two vectors can be constructed between two satellites and a ground observation point respectively, and the satellite angular distance is the included angle between these two satellite vectors. The unit vector of the line - of - sight direction of satellite A is represented by using the azimuth angle and elevation angle of the satellite , and the unit vector of the line - of - sight direction of satellite B is , as follows:

[0056] (1)

[0057] In the formula, and are the azimuth angle and elevation angle of satellite A at moment respectively, and are the azimuth angle and elevation angle of satellite B at moment respectively. According to the relationship between the dot - product of vectors and the included angle, it can be obtained that

[0058] (2)

[0059] The satellite angular distance can be calculated through vector dot - product and inverse - trigonometric function operations.

[0060] (3)

[0061] According to the satellite angular distance calculation formula (3), the angular distance value between any two satellites can be given, and the objects to be evaluated for spatial matching are judged based on the magnitude of the angular distance value. The following gives the implementation process of satellite spatial matching.

[0062] During the satellite spatial matching process, in an open environment the number of satellites observed at a certain moment is m, and in a complex environment the number of satellites observed at a certain moment is n. Theoretically, there are types of matching situations between the satellites in the open environment and those in the complex environment. For each situation, the angular distance of satellite pairs needs to be calculated according to the matching relationship of the satellites, and the average value is taken to measure the closeness of the satellites under the current matching condition. The situation with the smallest average angular distance is selected as the matching relationship between the satellites in the open environment and those in the complex environment. However, the above method of traversing all satellites for matching has problems such as excessive calculation amount and long time consumption in actual use, and cannot meet the requirements of matching calculation efficiency. Therefore, in order to improve the matching efficiency and reliability, the present invention simplifies the processing during satellite spatial matching, changing the overall matching of all observed satellites to one-by-one matching of satellites.

[0063] By calculating the angular distance between the satellites in the open environment and those in the complex environment according to the angular distance calculation formula (1), the angular distance of satellite pairs can be obtained. The spatial matching for determining the satellite matching relationship satisfies two principles. Principle ①: The satellites that have successfully matched cannot be reused, and the satellites that have completed the matching do not participate in the matching of other satellites subsequently; Principle ②: Priority is given to considering the satellite pairs with small angular distances. The satellite pairs with the smallest current angular distance are selected in sequence until there are no satellites available for selection, and the matching of all satellites is completed. The detailed implementation process of satellite spatial matching is as Figure 5 . In this document, it is not limited to using three satellites A, B, and C at a certain moment in the open environment and two satellites D and E at a certain moment in the complex environment as the implementation cases of the present invention to elaborate on the satellite spatial matching process and explain the above algorithm process:

[0064] First, calculate the angular distance between each satellite in the open environment and each satellite in the complex environment according to the angular distance calculation formula (1) to obtain the angular distance values between each satellite in the open environment and each satellite in the complex environment, and form an angular distance value sequence.

[0065] Secondly, select the smallest angular distance from the above angular distance value sequence and determine the satellite pair corresponding to the smallest angular distance. Here, taking satellite C and satellite D as an example, they are used as the satellite pair at this moment.

[0066] Furthermore, the satellites that are successfully matched at this time are determined through the satellite pairs corresponding to the above minimum angular distance. Here, taking Satellite C and Satellite D as an example, they are used as the successfully matched satellite pair. At the same time, the satellites that have been successfully matched will no longer participate in subsequent satellite matching, that is, the minimum angular distance that has completed satellite matching is deleted from the angular distance numerical sequence. Then, at this time, the open environment satellites are A and B, and the complex environment satellites are E.

[0067] Then, the minimum angular distance is selected from the new angular distance numerical sequence, and the satellite pair corresponding to the minimum angular distance is determined. The satellites that are successfully matched at this time are determined through the satellite pair corresponding to the minimum angular distance and used as the successfully matched satellite pair.

[0068] Finally, the above process is repeated until all available satellites are matched, ending the satellite spatial matching process and establishing successfully matched satellite pairs.

[0069] The above process can complete the spatial matching of open environment satellites and complex environment satellites, obtain satellite pairs that can be spatially matched, and provide a basic guarantee for the correctness of subsequent satellite signal grafting work.

[0070] (2) Implementation method of satellite time matching

[0071] Satellite spatial matching calculates and analyzes satellite pairs at a certain moment, while satellite time matching needs to consider all data within a time period, that is, calculate the angular distances at each moment within the time period to measure the matching degree of satellites within that time period. The schematic diagram of the angular distance between two satellites during satellite time matching is shown in Figure 4 , and the observable time periods of Satellite A and Satellite B are and respectively, and the lengths of both are the same. At time , the angular distance between Satellite A and Satellite B at time is . The average angular distance is used to represent the closeness of the distribution of Satellite A within the time period and Satellite B within the time period

[0072] (4)

[0073] During the satellite time matching process of any two satellites, first, according to the satellite angular distance calculation formula (3), the angular distance value between Satellite A and Satellite B at a certain moment can be given, and then the average angular distance formula (4) is used to calculate the average angular distance between Satellite A and Satellite B within a certain time period.

[0074] During the satellite time matching process, there are satellite data within the time period for the open environment data, and the satellite signals to be grafted are in During a period Some satellites have observation errors. In order to make full use of satellite observation data, when matching satellite time, satellite data with a length of is retained, and satellite data with a length of is matched from the complex environment data. The satellite time matching process is as shown in Figure 6 This invention describes the implementation process taking as an example, but does not limit that this invention is still applicable to the case of . The specific implementation process of satellite time matching is as follows:

[0075] Step 1: When , retain the entire segment of satellite error data to be grafted, and intercept satellite data with a time length of starting from the start time of the open environment data. The number of satellite observations in the open environment during the period is satellites, and the number of satellite observations in the complex environment during the period is satellites.

[0076] Step 2: Calculate the satellite matching situation between the satellite data intercepted in the open environment period and the satellite error data to be grafted. It should be noted that here this invention uses the mean angular distance to describe the closeness of the sky distribution of two satellites in a certain period. Therefore, first calculate the angular distance value of the satellite pair composed of the satellite data intercepted in the open environment period and the satellite error data to be grafted at each moment according to formula (3), and then take the mean value of the angular distance values of this satellite pair within the selected period to obtain the mean angular distance of this satellite pair within this period, and use the mean angular distance as the matching index of this satellite pair within this period.

[0077] Step 3: Calculate the mean angular distance of all satellite pairs within the above same period, and complete satellite spatial pairing according to the satellite spatial matching process.

[0078] Step 4: Use the satellite pairing and the mean angular distance of each satellite pair calculated in Step 3 to calculate the average angular distance according to formula (4). This invention uses the average angular distance as the matching index of all satellite pairs within this period.

[0079] Step 5: Move the data interception window by one epoch in the open environment satellite data (i.e., the translation amount is expressed as ), as the next interception period, and repeat the process of Steps 2 - 4 until , indicating that the entire segment of open environment satellite data has been traversed.

[0080] Step 6: Select the time period with the smallest average angular distance value of the satellite pairs during all time periods in the above translation process as the final result of satellite time matching.

[0081] Since it is necessary to traverse the entire satellite data in the open environment, if all situations in the satellite spatial matching process are traversed, it will lead to a very large amount of satellite matching calculations. Even if the simplified satellite spatial matching method is used to only calculate the angular distance of each corresponding moment of the satellite pair, the amount of calculation in this case is also very large. Therefore, considering the direction characteristics of satellite operation, the present invention can be simplified to only select several typical moments for calculating the average angular distance during the specific implementation process, such as only calculating the average angular distance at the start moment, the middle moment, and the end moment of the time period, and using the time period with the smallest average angular distance value among these three moments as the satellite time matching result.

[0082] The embodiment of the present invention implements and verifies the method of the present invention based on the PC side. Refer to Figure 7 Figures (a)-(b) and Figure 8 Figures (a)-(b).

[0083] The most intuitive way to verify the correctness of the satellite spatio-temporal matching method is to directly check the satellite matching situation in the same region and at the same time period, that is, to collect data in the same region and at the same time for the open environment data and the complex environment data. In this case, the satellites in the open environment can be perfectly matched with the satellites in the complex environment. According to the above implementation process, the present invention prepared satellite data with a length of 3 hours to verify the satellite spatio-temporal matching method during verification. During the verification process, a scenario where the length of the simulated complex environment data is greater than the length of the open environment data is set, and the middle 1-hour data is intercepted as the open environment data, and the complete 3-hour data is used as the complex environment data. The purpose of this verification design scheme is to verify both the satellite spatial matching ability and the satellite time matching ability. Figure 7 In Figures (a) and (b), the satellite sky maps of the open environment and the complex environment under the experimental verification conditions are respectively shown. In the sky maps of (a) and (b), the successfully matched parts of the satellites are represented by the same color trajectories, and the gray trajectories represent the satellites that are not successfully matched. The "r" after the satellite number indicates the satellite in the open environment, and being marked in red indicates that the satellite is successfully matched; the "mp" after the satellite number indicates the satellite in the complex environment. Comparing Figure 7 Figures (a) and (b), it can be seen that the satellites in the open environment and the satellites in the complex environment are correctly matched both spatially and temporally. In addition, to further verify the correctness of the implementation of the satellite spatio-temporal matching, the present invention also sets a scenario where the length of the urban complex environment data is less than the length of the open environment data, intercepts the middle 1-hour data as the complex environment data, and uses the complete 3-hour data as the open environment data. The obtained satellite matching results are Figure 7 basically the same, and can also achieve correct satellite spatio-temporal matching. Therefore, the specific satellite sky distribution maps are not repeated here.

[0084] One special note: The reason why the satellite trajectory in the sky map does not show interruption is that the present invention regards the satellite signal interruption as a special extreme (environmental) error. Therefore, the satellite error sequence is continuous (i.e., the satellite observations are continuous), so the satellite trajectory is also continuous. At this time, when calculating the azimuth and elevation angles of the satellite, first determine the start and end times when the satellite has real observation values, and then calculate the azimuth and elevation angles during this period. The azimuth and elevation angles are not calculated during the satellite interruption period.

[0085] In addition, to further verify the satellite matching situation at different times of a day, the present invention also uses dynamic measured data in open environments and complex environments to investigate the dynamic satellite matching effect and the average angular distance constraint. Figure 8 The satellite matching results in open environments and complex environments under dynamic conditions considering the average angular distance constraint are given. Generally speaking, after adding the average angular distance limit, satellite matching pairs with large differences in trajectories can be eliminated, and the remaining trajectories are relatively close. Specifically, in Figure 8 (a), the average angular distance between G32_r and G31_mp matching (yellow) is 38.22°, the average angular distance between G16_r and G04_mp matching (orange) is 31.17°, and the average angular distance between G27_r and G28_mp matching (light purple) is 64.91°. There are obvious differences in the sky distributions of these three groups of satellites in open environments and satellites in complex environments, and their average angular distance values are also large. If the average angular distance value is not constrained, it will lead to large differences in the sky distribution characteristics after satellite spatio-temporal matching. Therefore, the constraint condition of the average angular distance being less than or equal to 30° is adopted, and the satellite matching results that meet this constraint condition of the average angular distance are selected (see Figure 8 (b)), which can effectively eliminate unreasonable satellite matching pairs and ensure that the sky distribution characteristics after satellite matching are basically consistent.

[0086] The present invention establishes the angular distance information based on the combination of elevation angle and azimuth angle as the satellite matching index. At the same time, during the satellite matching process, spatial consistency and temporal consistency are taken into account to ensure the continuity and correctness of the satellite motion trajectory within the time period after matching.

[0087] The implementation basis of each embodiment of the present invention is achieved through programmed processing by a device with a processor function. Therefore, in engineering practice, the technical solutions and functions of each embodiment of the present invention are encapsulated into various modules. Based on this actual situation, on the basis of the above embodiments, the embodiment of the present invention provides a Beidou / GNSS satellite time and space matching system based on angular distance, which is used to execute a Beidou / GNSS satellite time and space matching method based on angular distance in the above method embodiments.

[0088] See Figure 9, the system includes: a satellite angular distance calculation module, which is used to establish a satellite angular distance calculation model based on the elevation angle and azimuth angle, and calculate and form a sequence of angular distance values; a satellite spatial matching module, which is used to screen the satellite pairs corresponding to the minimum angular distance one by one based on the constructed sequence of angular distance values, and perform satellite spatial matching in sequence; a satellite average angular distance calculation module, which is used to calculate the average angular distance of all satellites within a selected time period based on the constructed sequence of angular distance values; a satellite time matching module, which is used to use the calculated average angular distance as the matching index of all satellites within a selected time period to perform satellite time matching.

[0089] An angular distance-based Beidou / GNSS satellite time and space matching system provided by an embodiment of the present invention aims at the problems of "many-to-many" satellites and inconsistent data lengths in GNSS / Beidou error grafting, and adopts Figure 9 several modules therein to construct angular distance information between satellites based on the elevation angle and azimuth angle, and establish an angular distance value as the evaluation index for satellite matching; taking into account both satellite spatial matching and time matching, using the angular distance evaluation to have better consistency in the satellite positions at a fixed moment, and at the same time using the average angular distance evaluation to have better consistency in the satellite movement trajectories within a certain time period.

[0090] It should be noted that the system embodiments provided by the present invention are used not only to implement the methods in the above method embodiments, but also to implement the methods in other method embodiments provided by the present invention. The difference is only in setting the corresponding functional modules, and its principle is basically the same as that of the above system embodiments provided by the present invention. As long as those skilled in the art, on the basis of the above system embodiments, refer to the specific technical solutions in other method embodiments, obtain the corresponding technical means by combining technical features, and the technical solutions constituted by these technical means, and on the premise of ensuring the practicability of the technical solutions, improve the modules in the above system embodiments to obtain the corresponding system-like embodiments for implementing the methods in other method-like embodiments. For example:

[0091] Based on the content of the above system embodiments, as a preferred embodiment, in an angular distance-based Beidou / GNSS satellite time and space matching system provided by an embodiment of the present invention, the satellite angular distance calculation module is further used to execute the following instructions:

[0092] Calculate the satellite angular distance using the elevation angles and azimuth angles of two satellites to obtain the angular distance value of these two satellites at this moment, and traverse all the satellite numbers one by one to form a sequence of angular distance values between different satellites.

[0093] Based on the content of the above system embodiments, as a preferred embodiment, in an angular distance-based Beidou / GNSS satellite time and space matching system provided by an embodiment of the present invention, the satellite spatial matching module is further used to execute the following instructions:

[0094] Determine the satellite pair corresponding to the minimum angular distance from the constructed sequence of angular distance values between different satellites as the optimal matching result of these two satellites, and at the same time delete all angular distance values corresponding to these two satellites in the sequence of angular distance values;

[0095] Select the minimum angular distance from the new sequence of angular distance values in turn, and determine the satellite pair corresponding to the minimum angular distance at this time until all satellite pairs are selected, completing the satellite spatial matching.

[0096] Based on the content of the above system embodiment, as a preferred embodiment, in the Beidou / GNSS satellite time and space matching system based on angular distance provided in the embodiment of the present invention, the satellite average angular distance calculation module is further configured to execute the following instructions:

[0097] Calculate the angular distance value of the satellite pair to be matched at each moment, and take the average value of the angular distance values of the satellite pair to be matched within the selected time period to obtain the angular distance average value of the satellite pair to be matched within the selected time period;

[0098] Use the obtained satellite pairing and the angular distance average value of each satellite pair to calculate the average angular distance of all satellites within the selected time period.

[0099] Based on the content of the above system embodiment, as a preferred embodiment, in the Beidou / GNSS satellite time and space matching system based on angular distance provided in the embodiment of the present invention, the satellite time matching module is further configured to execute the following instructions:

[0100] Take the average angular distance as the matching index of all satellite pairs within the selected time period, and calculate the average angular distance of satellites through translation in multiple time periods to obtain a sequence of average angular distance values in multiple time periods;

[0101] Judge the average angular distance values of satellite pairs in all time periods, and take the time period with the minimum average angular distance value as the final result of satellite time matching, completing the satellite time matching.

[0102] Based on the same inventive concept as the above embodiment, the embodiment of the present invention further provides a Beidou / GNSS satellite time and space matching device based on angular distance, including a memory and a processor, the memory stores program instructions executed by the processor, and the processor calls the program instructions to execute the steps of the Beidou / GNSS satellite time and space matching method based on angular distance.

[0103] In an embodiment of the present invention, the memory may be a non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), etc., or may also be a volatile memory, such as a random-access memory (RAM). The memory is any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory in the embodiment of the present invention may also be a circuit or any other device capable of implementing a storage function, for storing program instructions and / or data.

[0104] In an embodiment of the present invention, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, and can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present invention. The general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present invention may be directly embodied as being executed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

[0105] Based on the same inventive concept as the above embodiments, the embodiment of the present invention further provides a non-transitory computer-readable storage medium, and the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions cause the computer to execute the steps of the above-mentioned Beidou / GNSS satellite time and space matching method based on angular distance.

[0106] In summary, the Beidou / GNSS satellite time and space matching method based on angular distance provided by the present invention includes: (1) establishing a satellite angular distance calculation model based on the satellite altitude angle and azimuth angle; (2) for satellite space matching, determining the satellite pair corresponding to the minimum angular distance from the angular distance numerical sequence as the optimal result of the space matching of these two satellites, and sequentially selecting the minimum angular distance from the new angular distance numerical sequence to complete the space matching of all satellites; (3) calculating the angular distance mean using the angular distance values of the satellite pairs to be matched at each moment, and calculating the average angular distance of all satellites during this period using the obtained satellite pairs and the angular distance means of each satellite pair; (4) realizing the calculation of the average angular distance of satellites in multiple time periods through translation, obtaining the average angular distance numerical sequence in multiple time periods, judging the average angular distance values of satellite pairs in all time periods, and taking the time period with the minimum average angular distance value as the final result of satellite time matching to complete satellite time matching. The present invention is applicable to the scenario of Beidou / GNSS satellite signal grafting, is not affected by the poor matching accuracy of a single altitude angle or azimuth angle, takes into account both satellite time and space matching, can provide rich sample data for satellite precise positioning and integrity monitoring of integrated navigation, and solves the problem of high cost in actual measurement data acquisition.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A BeiDou / GNSS satellite time and space matching method based on angular distance is applicable to BeiDou / GNSS satellite signal grafting scenarios, and is characterized by: include: A satellite angular distance calculation model is established based on the altitude angle and azimuth angle to calculate and form an angular distance numerical sequence; Based on the constructed angular distance numerical sequence, the satellite pairs corresponding to the minimum angular distance are selected one by one, and satellite spatial matching is performed in sequence; Based on the constructed angular distance value sequence, the average angular distance of all satellites in the selected period is calculated; The calculated average angular distance is used as the matching index of all satellites in the selected time period to perform satellite time matching.

2. The BeiDou / GNSS satellite time and space matching method based on angular distance according to claim 1, characterized in that: A satellite angular distance calculation model is established based on the altitude angle and azimuth angle to calculate the angular distance numerical sequence, including: The satellite angular distance is calculated using the altitude and azimuth angles of the two satellites to obtain the angular distance value of the two satellites at that moment, and all satellite numbers are traversed one by one to form a sequence of angular distance values ​​between different satellites.

3. The BeiDou / GNSS satellite time and space matching method based on angular distance according to claim 1, characterized in that: The satellite pairs corresponding to the minimum angular distance are selected one by one, and satellite spatial matching is performed in sequence, including: Determine the satellite pair corresponding to the minimum angular distance from the constructed sequence of angular distance values ​​between different satellites as the optimal matching result of the two satellites, and delete all angular distance values ​​corresponding to the two satellites in the sequence of angular distance values; The minimum angular distance is selected from the sequence of new angular distance values ​​in turn, and the satellite pair corresponding to the minimum angular distance at this time is determined until all satellite pairs are selected and the satellite spatial matching is completed.

4. The BeiDou / GNSS satellite time and space matching method based on angular distance according to claim 1, characterized in that: Calculate the average angular distance of all satellites during the target period, including: Calculate the angular distance value of the satellite pair to be matched at each moment, take the average of the angular distance values ​​of the satellite pair to be matched in the selected time period, and obtain the average angular distance value of the satellite pair to be matched in the selected time period; The average angular distance of all satellites in the selected period is calculated using the obtained satellite pairings and the average angular distance of each satellite pair.

5. The BeiDou / GNSS satellite time and space matching method based on angular distance according to claim 4, characterized in that: Perform satellite time matching, including: The average angular distance is used as the matching index of all satellite pairs in the selected period, and the average angular distance of satellites in multiple time periods is calculated by translation to obtain the average angular distance value sequence in multiple time periods; The average angular distance value of the satellite pairs in all time periods is judged, and the time period with the smallest average angular distance value is taken as the final result of satellite time matching to complete satellite time matching.

6. The BeiDou / GNSS satellite time and space matching system based on angular distance is suitable for BeiDou / GNSS satellite signal grafting scenarios, characterized by: include: A satellite angular distance calculation module is used to establish a satellite angular distance calculation model based on the altitude angle and the azimuth angle, and calculate and form an angular distance numerical sequence; The satellite space matching module is used to select the satellite pairs corresponding to the minimum angular distance one by one based on the constructed angular distance value sequence, and perform satellite space matching in sequence; The satellite average angular distance calculation module is used to calculate the average angular distance of all satellites in a selected period based on the constructed angular distance value sequence; The satellite time matching module is used to perform satellite time matching by using the calculated average angular distance as the matching index of all satellites in the selected time period.

7. A BeiDou / GNSS satellite time and space matching device based on angular distance, characterized in that: It comprises a memory and a processor, wherein the memory stores program instructions executed by the processor, and the processor calls the program instructions to execute the steps of the Beidou / GNSS satellite time and space matching method based on angular distance as described in any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium stores computer instructions, which enable the computer to execute the steps of the Beidou / GNSS satellite time and space matching method based on angular distance as described in any one of claims 1 to 5.

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