Rapid searching and positioning method and system based on network RTK one-way transmission

Abstract

The invention relates to the technical field of satellite navigation and positioning, in particular to a fast searching and positioning method and system based on network RTK one-way transmission, and the method comprises the steps: carrying out the grid division of a coverage geographic area of each reference station by taking equal latitude and longitude intervals as a criterion, numbering each grid point, and taking the numbered grid point as a virtual reference station; the central processing center receives the accurate coordinates and the real-time observation data of each reference station, calculates and generates a virtual observation value of each grid point, and stores the virtual observation value; designing a grid data coding format, and coding the virtual observation value; and the central processing center broadcasts the coded virtual observation values to the moving station, and after the moving station receives the virtual observation values of the grid points, the optimal grid point is selected by using a rapid search method to perform positioning calculation, so that real-time high-precision positioning is realized. According to the method, the concurrent processing capability of the system can be improved, the security of the system is improved, the system efficiency is improved through a quick search method, and finally accurate positioning service is realized.

Description

Technical Field

[0001] The present invention relates to the field of satellite navigation and positioning technology, and in particular to a fast search and positioning method and system based on network RTK one-way transmission. Background Art

[0002] Network RTK (Network Real-Time Kinematic) is a high-precision real-time positioning technology based on the Global Navigation Satellite System (GNSS). Network RTK deploys multiple base stations in a large area and transmits the data of these base stations to a central processing center through the network. The central processing center integrates the data of multiple base stations, calculates the system error, and provides more accurate differential correction data to the mobile station for high-precision positioning. It overcomes the problems of limited base station coverage, error growth with distance, and large multipath effect of traditional RTK technology, and provides a wider range and higher precision positioning service.

[0003] At present, network RTK widely uses virtual reference station (VRS) technology. The central processing center needs to generate a virtual reference station based on the approximate coordinates of the mobile station. Therefore, a two-way data transmission mode is adopted between the central processing center and the mobile station (such as Figure 1 The mobile station sends the approximate coordinates to the central processing center, and the central processing center transmits the differential correction data or virtual reference station data to the mobile station through NTRIP (Networked Transport of RTCM via Internet Protocol) or other protocols.

[0004] In the network RTK system, the data encoding formats used for data transmission are mainly RTCM (Radio Technical Commission for Maritime Services) format and NMEA (National Marine Electronics Association) format. RTCM format is used to transmit GNSS observation data and correction data. NMEA format is used for the mobile station to report its current position information to the processing center, or for base station status monitoring.

[0005] The mobile station receives correction data or virtual reference station data and combines it with its own GNSS observation data to perform differential calculations to obtain high-precision positioning.

[0006] Existing network RTK technology, especially the system based on virtual reference station (VRS), needs to dynamically generate a virtual reference station for each mobile station and perform real-time correction data calculation based on it. This method will significantly increase the computing burden of the central processing center when the number of mobile stations increases, reduce the response speed of the system, and may even fail to process the requests of all mobile stations in time, thus forming a user access restriction problem.

[0007] Traditional VRS technology relies on a two-way data communication mode, requiring the mobile station equipment to send an approximate position to the central processing center to generate the corresponding correction data. This mode not only increases the complexity of data transmission, but also has certain security risks, because the location information of the mobile station may be intercepted or tampered with during the transmission process, resulting in privacy leakage or system attacks. In addition, the existing RTCM protocol does not support the transmission of gridded data, further limiting the efficiency of data transmission and grid density. Summary of the invention

[0008] The present invention aims to solve the problems of high concurrent processing burden and insufficient data transmission security in the prior art, and proposes a fast search and positioning method and system based on network RTK one-way transmission, which can realize fast search and positioning.

[0009] To achieve the above purpose, the technical solution adopted is:

[0010] A fast search and positioning method based on network RTK one-way transmission, comprising:

[0011] The geographical area covered by each base station is divided into grids with equal latitude and longitude intervals, and each grid point is numbered and used as a virtual reference station;

[0012] The central processing center receives the precise coordinates and real-time observation data of each base station, calculates and generates virtual observation values ​​for each grid point and stores them;

[0013] Design grid data encoding format to encode virtual observation values;

[0014] The central processing center broadcasts the encoded virtual observation values ​​to the mobile station through broadcasting. After receiving the virtual observation values ​​of the grid points, the mobile station uses a fast search method to select the optimal grid point for positioning and solution, thereby achieving real-time and high-precision positioning.

[0015] According to the fast search and positioning method based on network RTK one-way transmission of the present invention, further, each grid point is numbered using the Geohash code of the longitude and latitude coordinates of the grid point, and a Geohash code is assigned to each grid point;

[0016] The Geohash encoding process is as follows: first determine the longitude and latitude of the grid point; set the encoding precision; then convert the longitude and latitude into binary form; alternately combine the binary bits of longitude and latitude; convert to Base32 format to obtain the Geohash encoding string.

[0017] According to the fast search and positioning method based on network RTK one-way transmission of the present invention, a grid data encoding format is further designed. The encoding format is based on RTCM and includes four parts: a custom header, grid position information, data information, and a check bit. The encoding structure of each grid point is defined as follows:

[0018]

[0019]

[0020] Where: Nsat is the number of satellites; Nsig is the number of signals;

[0021] The grid point number in the custom header in the table is the Geohash code of the longitude and latitude coordinates of the grid point. The data information part supports single Beidou at the B1I / B3 frequency point, and the grid position information uses RTCM MT 1032 or RTCM MT 1006 type data.

[0022] According to the fast search and positioning method based on network RTK one-way transmission of the present invention, further, using the fast search method to select the optimal grid point for positioning solution includes:

[0023] The rover stores all grid point data in a data structure;

[0024] Obtain the latitude and longitude coordinates of the mobile station to determine the location of the mobile station;

[0025] Convert the latitude and longitude of the rover location to the corresponding Geohash code using the same accuracy as the entire grid;

[0026] Use the Geohash code of the rover as the search key to search for the Geohash code of the corresponding grid point from the data structure; if the corresponding grid point is matched, proceed to the next step; if no grid point is found, the Geohash code of the rover is reduced by one digit and searched again to obtain all adjacent grid points;

[0027] If only one grid point is matched, it is the nearest grid point; if multiple grid points are matched, all grid points are traversed, and the Haversine formula is used to calculate the actual distance between the mobile station position and the grid point, and the calculated distances are sorted to determine the nearest grid point;

[0028] Returns the virtual observation value of the nearest grid point.

[0029] Furthermore, the present invention also provides a rapid search and positioning system based on network RTK one-way transmission, comprising a grid division and numbering module, a virtual observation value solving module, a grid encoding module and a search and positioning module, wherein:

[0030] The grid division and numbering module is used to divide the coverage area of ​​each reference station into grids with equal latitude and longitude intervals, and to number each grid point as a virtual reference station;

[0031] The virtual observation value calculation module is used for the central processing center to receive the precise coordinates and real-time observation data of each reference station, calculate and generate the virtual observation value of each grid point and store it;

[0032] The grid coding module is used to design the grid data coding format and encode the virtual observation values;

[0033] The search and positioning module is used by the central processing center to broadcast the encoded virtual observation values ​​to the mobile station. After the mobile station receives the virtual observation values ​​of the grid points, it uses a fast search method to select the optimal grid point for positioning solution to achieve real-time and high-precision positioning.

[0034] The beneficial effects achieved by adopting the above technical solution are:

[0035] 1. Reduce the computing burden and improve the system's concurrent processing capabilities.

[0036] By dividing the base station coverage area into multiple fixed grids and pre-calculating and storing correction data for each grid point, the present invention greatly reduces the real-time computing burden under high concurrency conditions. Users no longer need to dynamically generate virtual reference stations, but can directly obtain correction information from pre-calculated grid point data, thereby improving the system's response speed and concurrent processing capabilities.

[0037] 2. Improve data transmission efficiency and enhance security.

[0038] The present invention designs a grid data encoding format, which transmits the correction data to the mobile station in a compact and secure manner through a one-way data transmission mode, avoiding the leakage of the mobile station position information in two-way communication. At the same time, the check bit included in the encoding structure ensures the integrity and accuracy of the data transmission.

[0039] 3. Provide quick search methods and optimize positioning services.

[0040] Through the fast search method based on Geohash coding, the present invention can realize efficient positioning and data retrieval of the nearest grid of the mobile station, ensuring that the mobile station can quickly obtain the optimal correction data, thereby realizing more accurate positioning services. This search method utilizes the hierarchical structure and proximity characteristics of Geohash coding, significantly improving the efficiency of the system and user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention, wherein the drawings are only used to illustrate some embodiments of the present invention, but not to limit all embodiments of the present invention thereto.

[0042] Figure 1 It is a schematic diagram of the existing network RTK working mode using virtual reference station technology;

[0043] Figure 2 It is a flowchart of a fast search and positioning method based on network RTK one-way transmission according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings of specific embodiments of the present invention to clearly and completely describe the exemplary scheme of the embodiment of the present invention. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field.

[0045] like Figure 2 As shown, this embodiment discloses a fast search and positioning method based on network RTK one-way transmission, which includes the following contents:

[0046] Step S101: divide the geographical area covered by each reference station into grids with equal latitude and longitude intervals, and number each grid point as a virtual reference station.

[0047] The divided grid points are numbered using the Geohash encoding of the longitude and latitude coordinates of the grid points. The Geohash encoding process is as follows: first determine the longitude and latitude of the grid points; set the encoding accuracy; then convert the longitude and latitude into binary form; alternately combine the binary bits of longitude and latitude; convert to Base32 format to obtain the Geohash encoding string.

[0048] The grid point number uses Geohash coding, which is used by the rover to quickly search and select grid points. Geohash is a geographic location coding system based on latitude and longitude. It divides the earth's surface into grids and assigns a unique code to each grid point. Using this feature of Geohash, the network RTK service area is divided into multiple grids, and a Geohash code is assigned to each grid, thereby achieving efficient management and retrieval of network RTK data.

[0049] Step S102: The central processing center receives the precise coordinates and real-time observation data of each reference station, calculates and generates virtual observation values ​​for each grid point, and stores them.

[0050] Specifically, a triangle network of base stations is constructed, the real-time observation data of the base stations are used to solve the network baseline, and the atmospheric delay error is interpolated to each grid point virtual observation station to generate the corresponding virtual observation value.

[0051] Step S103: To achieve efficient data transmission and processing, when the traditional RTCM protocol does not support grid data communication, a grid data encoding format is developed and designed to encode virtual observation values.

[0052] Different from the traditional network RTK two-way transmission mode (i.e. receiving the approximate coordinates of the mobile station and generating and broadcasting a single virtual reference station data), network RTK uses a one-way transmission mode to broadcast virtual observation values. In this mode, multiple grid point virtual observation values ​​need to be broadcast to the same mobile station. Currently, there is no applicable format for grid data encoding, so it is necessary to expand and modify the traditional standard RTCM protocol encoding format. A custom grid data encoding format is proposed. The encoding format is based on RTCM, combines the required information and data, adds a custom header, and defines the grid point related information field to form a new grid data encoding format.

[0053] The main differences between the grid data encoding format and the traditional RTCM data format are:

[0054] (1) Add a custom header for the rover to quickly search and select grid points.

[0055] (2) Add a grid point number field to define the Geohash number content of each grid point.

[0056] (3) Define the grid point location information and data information content.

[0057] The encoding structure of each grid point is defined in the following table:

[0058] Table 1 Grid point coding structure table

[0059]

[0060]

[0061] Where: Nsat is the number of satellites; Nsig is the number of signals.

[0062] The coding structure consists of four parts: custom header, grid location information, data information, and check digit. The grid point number in the custom header is the Geohash code of the longitude and latitude coordinates of the grid point. The data information part supports single Beidou at the B1I / B3 frequency point, and the grid location information uses RTCM MT 1032 or RTCM MT 1006 type data.

[0063] Step S104: The central processing center broadcasts the encoded virtual observation values ​​to the mobile station through broadcasting. After receiving the virtual observation values ​​of the grid points, the mobile station uses a fast search method to select the optimal grid point for positioning and solving, thereby achieving real-time and high-precision positioning.

[0064] This embodiment proposes a fast search method based on Geohash coding, which can quickly locate the nearest grid of the mobile station and retrieve relevant data. The search method uses the hierarchical structure and proximity characteristics of Geohash coding to achieve fast grid positioning and data retrieval. The specific implementation steps are as follows:

[0065] Step S1041: The mobile station pre-processes the Geohash codes of all grid points and other data and other information, and stores them in an efficient data structure (hash table).

[0066] Step S1042: Obtain the longitude and latitude coordinates of the mobile station to determine the location of the mobile station.

[0067] Step S1043: Use the same accuracy as the entire grid to convert the longitude and latitude of the mobile station position into the corresponding Geohash code.

[0068] Step S1044, using the Geohash code of the mobile station as the search key to search the hash table for the Geohash code of the corresponding grid point, here all grid points containing the Geohash code of the mobile station are matched (for example: the Geohash code of the mobile station is webzz7, and it can match the grid point Geohash code of webzz7, webzz7d or webzz7a, etc.); if the corresponding grid point is matched, the next step can be carried out. If the grid point cannot be found, the Geohash code of the mobile station is reduced by one bit and searched again to obtain all adjacent grid points.

[0069] Step S1045: If only one grid point is matched, it is the nearest grid point; if multiple grid points are matched, traverse all grid points, use the Haversine formula to calculate the actual distance between the mobile station position and the grid point, and sort the calculated distances to determine the nearest grid point.

[0070] The Haversine formula is as follows:

[0071]

[0072] d = R. Haversin -1 (Haversin(φ2-φ1)+cosφ1cosφ2Haversin(λ2-λ1))

[0073] Among them, θ represents an arbitrary angle; R is the radius of the earth; λ1 and φ1 are the longitude and latitude of point A respectively; λ2 and φ2 are the longitude and latitude of point B respectively; d is the shortest distance between AB.

[0074] Step S1046: Return the virtual observation value of the nearest grid point. The mobile station performs differential calculation based on the virtual observation value (ie, correction data) and its own GNSS observation data to obtain high-precision positioning.

[0075] Corresponding to the above method, this embodiment also discloses a fast search and positioning system based on network RTK one-way transmission, comprising a grid division and numbering module, a virtual observation value solving module, a grid encoding module and a search and positioning module, wherein:

[0076] The grid division and numbering module is used to divide the geographical area covered by each base station into grids based on equal latitude and longitude intervals, and to number each grid point as a virtual reference station.

[0077] The virtual observation value calculation module is used by the central processing center to receive the precise coordinates and real-time observation data of each reference station, calculate and generate the virtual observation value of each grid point and store it.

[0078] The grid encoding module is used to design the grid data encoding format and encode the virtual observation values.

[0079] The search and positioning module is used by the central processing center to broadcast the encoded virtual observation values ​​to the mobile station. After the mobile station receives the virtual observation values ​​of the grid points, it uses a fast search method to select the optimal grid point for positioning solution to achieve real-time and high-precision positioning.

[0080] In summary, the base station coverage area is divided into grids according to certain criteria, and the correction data of each grid point is pre-calculated and stored, so that each grid point becomes a fixed virtual reference station (VRS). In view of the problem that the existing RTCM protocol does not support grid data transmission, the present invention proposes a dedicated grid data encoding format. The format includes a custom header, grid location information, data information and check bits, and in particular uses Geohash encoding to identify and locate grid points.

[0081] The present invention utilizes the hierarchical structure and proximity characteristics of Geohash coding to design a method for quickly searching and locating the nearest grid point of a rover. This method can efficiently retrieve and process relevant correction data, significantly improving the system's retrieval efficiency and positioning accuracy.

[0082] The present invention adopts a unidirectional data transmission mode to transmit pre-encoded grid correction data to the mobile station through broadcasting or other unidirectional communication methods, thereby avoiding the two-way transmission of the mobile station position information and improving the security of the system and the privacy protection of the mobile station.

[0083] Unless otherwise specifically stated, the relative steps, numerical expressions and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention.

[0084] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0085] The units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. A person of ordinary skill in the art may use different methods to implement the described functions for each specific application, but such implementation is not considered to be beyond the scope of the present invention.

[0086] Those skilled in the art will appreciate that all or part of the steps in the above method can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a disk or an optical disk. Optionally, all or part of the steps in the above embodiment can also be implemented using one or more integrated circuits, and accordingly, each module / unit in the above embodiment can be implemented in the form of hardware or in the form of software function modules. The present invention is not limited to any specific form of combination of hardware and software.

[0087] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A fast search and positioning method based on network RTK one-way transmission, characterized in that: Include: The geographical area covered by each base station is divided into grids with equal latitude and longitude intervals, and each grid point is numbered and used as a virtual reference station; The central processing center receives the precise coordinates and real-time observation data of each base station, calculates and generates virtual observation values ​​for each grid point and stores them; Design grid data encoding format and encode virtual observation values; The central processing center broadcasts the encoded virtual observation values ​​to the mobile station through broadcasting. After receiving the virtual observation values ​​of the grid points, the mobile station uses a fast search method to select the optimal grid point for positioning and solution, thereby achieving real-time and high-precision positioning.

2. The fast search and positioning method based on network RTK one-way transmission according to claim 1 is characterized in that: The grid points are numbered using the Geohash code of the grid point's longitude and latitude coordinates, and a Geohash code is assigned to each grid point; The Geohash encoding process is as follows: first determine the longitude and latitude of the grid point; set the encoding precision; then convert the longitude and latitude into binary form; alternately combine the binary bits of longitude and latitude; convert to Base32 format to obtain the Geohash encoding string.

3. The fast search and positioning method based on network RTK one-way transmission according to claim 2 is characterized in that: Design the grid data encoding format, which is based on RTCM and includes four parts: custom header, grid location information, data information, and check digit. The encoding structure of each grid point is defined in the following table: Where: Nsat is the number of satellites; Nsig is the number of signals; The grid point number in the custom header in the table is the Geohash code of the longitude and latitude coordinates of the grid point. The data information part supports single Beidou at the B1I / B3 frequency point, and the grid position information uses RTCM MT 1032 or RTCM MT 1006 type data.

4. The fast search and positioning method based on network RTK one-way transmission according to claim 3 is characterized in that: The use of fast search methods to select the optimal grid points for positioning solutions includes: The rover stores all grid point data in a data structure; Obtain the latitude and longitude coordinates of the mobile station to determine the location of the mobile station; Convert the latitude and longitude of the rover location to the corresponding Geohash code using the same accuracy as the entire grid; Use the Geohash code of the rover as the search key to search for the Geohash code of the corresponding grid point from the data structure; if the corresponding grid point is matched, proceed to the next step; if no grid point is found, the Geohash code of the rover is reduced by one digit and searched again to obtain all adjacent grid points; If only one grid point is matched, it is the nearest grid point; if multiple grid points are matched, all grid points are traversed, and the Haversine formula is used to calculate the actual distance between the mobile station position and the grid point, and the calculated distances are sorted to determine the nearest grid point; Returns the virtual observation value of the nearest grid point.

5. A fast search and positioning system based on network RTK one-way transmission, characterized in that: It includes a grid division and numbering module, a virtual observation value calculation module, a grid encoding module and a search and positioning module, among which: A grid division and numbering module is used to divide the coverage area of ​​each reference station into grids with equal latitude and longitude intervals, and to number each grid point as a virtual reference station; The virtual observation value calculation module is used for the central processing center to receive the precise coordinates and real-time observation data of each reference station, calculate and generate the virtual observation value of each grid point and store it; The grid coding module is used to design the grid data coding format and encode the virtual observation values; The search and positioning module is used by the central processing center to broadcast the encoded virtual observation values ​​to the mobile station. After the mobile station receives the virtual observation values ​​of the grid points, it uses a fast search method to select the optimal grid point for positioning solution to achieve real-time and high-precision positioning.

6. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 4.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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