PPP-rtk correction number broadcasting method and system

Abstract

This invention relates to a method and system for broadcasting PPP-RTK corrections. The method includes acquiring grid point information; determining correction information according to a dynamic partitioning method based on the satellite's orbital direction, satellite signal coverage area, and the grid point information; the correction information includes a header file, the grid point information, tropospheric corrections, and oblique ionospheric corrections; and uploading the correction information to an uplink station to control satellite broadcasting of the correction information. This invention solves the problems of satellite bandwidth allocation, correction area division, and correction data format encoding for PPP-RTK atmospheric delay corrections broadcast in low-Earth orbit satellite broadcasting areas.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of GNSS data processing, in particular to a PPP-RTK correction number broadcasting method and system. BACKGROUND

[0002] Low-orbit satellites with an orbital height below 1000 km play a significant role in many aspects due to their special applications and scientific research needs. In recent years, with the rapid development of low-orbit commercial constellations such as Hongyan and Rainbow Cloud, providing navigation and positioning enhancement services based on low-orbit constellations has become a research hotspot at home and abroad.

[0003] PPP-RTK enhancement services can help users obtain centimeter-level position solutions within a few seconds or tens of seconds, significantly reducing the waiting time for positioning services and significantly improving the efficiency of positioning work compared to the convergence time of several minutes to several tens of minutes without using the service. However, how to broadcast the PPP-RTK atmospheric delay correction number with high frequency and communication capability has been a problem plaguing the industry. Unlike traditional GNSS systems that are mainly used to transmit their own navigation signals, low-orbit navigation systems can carry enhancement service data by designing redundant frequency band information during planning. At the same time, thanks to the use of inter-satellite link technology, low-orbit satellite systems have the ability to update the uploaded information with high frequency, which makes it possible to implement large-scale PPP-RTK correction services.

[0004] Currently, low-orbit satellite systems used for navigation by multiple companies are still in the technical research and development and preparation stages, and there is no mature low-orbit navigation satellite system to provide large-scale PPP-RTK services as a precedent or demonstration application. The SBAS system in the United States and the QZSS system in Japan are currently available for enhancement services in medium and high orbits. The SBAS system does not provide regional atmospheric delay corrections, and the QZSS system only provides small-scale services to Japan through geostationary satellites. It is difficult to directly apply to the design of China's low-orbit PPP-RTK enhancement services,

[0005] How to design a set of low-orbit satellite broadcasting methods for China's multi-GNSS system PPP-RTK correction numbers has become a scientific and engineering application problem that needs to be solved urgently. SUMMARY

[0006] The purpose of the present application is to provide a PPP-RTK correction number broadcasting method and system to solve the problems of satellite bandwidth allocation, correction number regional division, and correction number data format coding for low-orbit satellite broadcasting of regional PPP-RTK atmospheric delay corrections.

[0007] To achieve the above purpose, the present application provides the following scheme:

[0008] A PPP-RTK correction number broadcasting method, comprising:

[0009] acquiring grid point information;

[0010] determining correction information according to a satellite running direction, a satellite signal coverage area, and the grid point information in a dynamic partitioning manner; the correction information including a header file, the grid point information, troposphere correction, and oblique ionosphere correction;

[0011] uploading the correction information to an injection station to control a satellite to broadcast the correction information through the injection station.

[0012] Optionally, the acquiring of the grid point information specifically includes:

[0013] determining a grid deployment principle according to population differences of regions and meridians of the regions;

[0014] determining the grid point information according to the grid deployment principle and ionosphere areas of the regions.

[0015] Optionally, the dynamic partitioning manner is specifically a region partitioning manner in a cross-sweeping manner along the satellite running direction.

[0016] Optionally, the troposphere correction includes a troposphere fitting value and a troposphere residual value; and the oblique ionosphere correction includes an oblique ionosphere fitting value and an oblique ionosphere residual value.

[0017] Optionally, an expression of the troposphere fitting value is:

[0018] ΔT = T 00 + T 01 (φ-φ0) + T 10 (λ-λ0)

[0019] wherein φ and λ are respectively a longitude and a latitude of a point to be calculated, φ0 and λ0 are respectively a longitude and a latitude of a grid point at an end of a temporary sub-grid, and ΔT is a troposphere delay fitting value; T 00 and T 10 are respectively a 0-order and a 1-order fitting coefficient.

[0020] Optionally, after the uploading of the correction information to the injection station to control the satellite to broadcast the correction information through the injection station, the method further includes:

[0021] the injection station sending the correction information to a satellite within a field of view of the injection station;

[0022] the satellite within the field of view of the injection station transmitting the correction information to a satellite outside the field of view of the injection station through inter-satellite link data communication.

[0023] A PPP-RTK correction broadcasting system, comprising:

[0024] The acquisition module is configured to acquire grid point information.

[0025] The correction number information determination module is configured to determine correction number information according to the satellite running direction, the satellite signal coverage area, and the grid point information in a dynamic partition block manner; the correction number information comprises a header file, the grid point information, troposphere correction numbers, and oblique ionosphere correction numbers.

[0026] The uploading module is configured to upload the correction number information to an injection station to control a satellite to broadcast the correction number information through the injection station.

[0027] Optionally, the acquisition module specifically comprises:

[0028] The grid deployment principle determination unit is configured to determine a grid deployment principle according to population differences of regions and meridians of the regions.

[0029] The grid point information determination unit is configured to determine grid point information according to the grid deployment principle and ionosphere areas of the regions.

[0030] According to the specific embodiments of the present application, the following technical effects are provided:

[0031] The present application acquires grid point information, determines correction number information according to the satellite running direction, the satellite signal coverage area, and the grid point information in a dynamic partition block manner, and uploads the correction number information to an injection station to control a satellite to broadcast the correction number information through the injection station. The present application can solve the problems of satellite bandwidth distribution, correction number area division, and correction number data format coding of low-orbit satellite broadcasted atmospheric delay correction numbers of regions of PPP-RTK. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0033] Figure 1 A schematic diagram is designed for a first-level grid point.

[0034] Figure 2 A schematic diagram is designed for a second-level encrypted grid point.

[0035] Figure 3 A schematic diagram is designed for a low-orbit satellite correction number limit broadcast range.

[0036] Figure 4 A correction number broadcast method for dynamic division of broadcast zones is shown in the figure;

[0037] Figure 5 A direction diagram for internal numbering is shown in the figure;

[0038] Figure 6 A temporary subnetwork division diagram is shown in the figure;

[0039] Figure 7 A PPP-RTK correction number broadcast method diagram is shown in the figure;

[0040] Figure 8 A PPP-RTK correction number broadcast method flow chart is shown in the figure. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0042] The purpose of the present application is to provide a PPP-RTK correction number broadcast method and system to solve the problems of satellite bandwidth allocation, correction number zone division and correction number data format coding of PPP-RTK atmospheric delay correction numbers in low-orbit satellite broadcast areas.

[0043] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0044] For the purpose of serving the whole country, a definition method of nationwide grid points, a division block broadcast mode and an atmospheric delay correction number expression format are designed. As shown in Figure 8 The present application provides a PPP-RTK correction number broadcast method for implementing PPP-RTK enhancement services in China, which mainly consists of three parts: a nationwide grid point deployment method, a division block broadcast mode design and an atmospheric delay correction number expression format design. The method specifically includes:

[0045] Step 101: Obtain grid point information. Step 101 specifically includes: determining a grid deployment principle according to population differences and meridians of an area; and determining grid point information according to the grid deployment principle and ionosphere regions of the area.

[0046] As shown in Figure 1 and Figure 2As shown, the service center publishes the predefined grid point number and location, the information of which will be built into the software system of the service end and the user. The key points of the nationwide grid point deployment method include: considering the population difference between the east and west, different grid deployment principles are used on both sides of the 97° east longitude; for the ionosphere active area and key city area south of 28° north latitude, a 0.33° interval secondary grid is designed.

[0047] The nationwide grid point deployment method:

[0048] The grid design and deployment must follow the changes in the atmospheric environment. Only in the areas where the atmospheric environment changes dramatically and the spatial correlation of the delay is weak, can a sufficient number of grid points be designed to meet the positioning accuracy requirements. In addition, three problems should be considered at the initial stage of grid design. First, the system design must consider the scalability of the service. Second, there are a large number of grasslands, snow-capped mountains, deserts and forest lands in the central and western regions of China, and it is costly to establish ground reference stations in these areas and the utilization rate is low. Third, for the ionosphere active area in southern China and the densely populated key areas (such as Beijing-Tianjin-Hebei, Yangtze River Delta, etc.), it is necessary to design a dense grid point. In summary, different interval two-level grids are deployed in the grid point design, and the population density difference between the east and west is taken into account.

[0049] The design of the first-level grid point is as Figure 1 China is divided into east and west parts by the 97° east longitude. The east of 97° line is a densely populated area, and it is considered that it is possible or will be possible to establish a dense grid. The grid points are densely distributed in the entire area with an interval of 1°, and each point is numbered from 1-001 to 1-762. 1 represents the first-level grid, and the last three digits are the intra-level number. In order to facilitate the positioning of the grid points in the correction number broadcast, a cross-level parallel number is designed, and the corresponding cross-level parallel number is 0001-0762. The invention refers to the "number" in the related description of the correction number format design.

[0050] For areas with a latitude lower than 28°, a secondary grid is used for encryption. Two points are added to each of the two grid points with a distance of 1°. The interpolation error in the correction number in the low-latitude area will be reduced to 1 / 3 of the original, reaching an error level similar to that in the high-latitude area. The interval of the encrypted grid is about 37km, as shown in Figure 2 The larger black grid points are first-level grid points, and the smaller gray grid points are secondary encrypted points, as shown in Figure 2 The area number is from 2-0001 to 2-1238, and the corresponding cross-level parallel number is 0763-2000.

[0051] Step 102: Determine the correction information using a dynamic partitioning method based on the satellite's direction of travel, the satellite signal coverage area, and the grid point information. The correction information includes the header file, the grid point information, the tropospheric correction, and the oblique ionospheric correction. Specifically, the dynamic partitioning method involves dividing the region into blocks in a sweeping motion along the satellite's direction of travel. The tropospheric correction includes the tropospheric fitted value and the tropospheric residual value; the oblique ionospheric correction includes the oblique ionospheric fitted value and the oblique ionospheric residual value.

[0052] Key aspects of the partitioned broadcast mode design include: adjustable satellite service area coverage lobe angle design; and a sweeping correction area partitioning method along the satellite's orbital direction, with partition size determined by the bandwidth of the broadcastable resources in the subframe. Key aspects of the atmospheric delay correction representation format include: a simplified representation method for grid point information based on number differences; and a subnetting method determined by the internal numbering of grid point areas.

[0053] like Figure 7 As shown, reference stations A, B, C, ..., X send correction information to the data service center. The data center, based on the satellite's direction of travel and signal coverage area, ... Figure 3 , Figure 4 The dynamic partitioning method shown determines the grid point number for each satellite to broadcast correction information in each frame over a period of time.

[0054] Design of correction data broadcasting mode for partitioned blocks:

[0055] The design concept of real-time service area adjustment is that each satellite only transmits correction values ​​for areas where its elevation angle reaches a certain threshold, and adjusts the service coverage area appropriately based on the amount of data transmitted. Initially, low-Earth orbit satellites are configured to only broadcast correction values ​​for areas where the receiver's elevation angle is higher than 25°. Figure 3 As shown. For a certain satellite (SAT), the limit of its signal coverage is within the tangent to the Earth's surface, with its intersection point E. Ground observations of the area within E′ of the satellite's zenith distance from the Earth's surface are considered to be within this area. In short, the area within E can receive the satellite's navigation signals and correction information, but the correction information only includes data from the area within E′; the augmentation service is unavailable for the area between E′ and E. Correction data for the area between E′ and E needs to be obtained from the satellite signal with the highest observable elevation angle in that area. At a zenith distance of 65°, the half-lobe angle is approximately 51°, and the coverage area of ​​the correction service is approximately twice the great circle segment, 1466 km, nearly 3000 km. The augmentation service coverage area is about one-fifth of the signal coverage area, significantly reducing the pressure on correction broadcasting.

[0056] In addition, the service area is adjustable, and the ground service system will estimate the data amount of the satellite transmission correction number at all times, and when the estimated data amount is not large and the channel resource is abundant, the lobe angle of the satellite transmission atmospheric delay correction number will be appropriately expanded, the service range thereof is expanded, and the channel resource is fully utilized.

[0057] The schematic diagram of the broadcasting scheme is shown in Figure 4 The coverage range of the satellite enhanced service in the initial position is a circle O, and the data of the first subframe is started to be broadcast. Before the first subframe is broadcast, the ground operation and control will estimate the data space of the atmospheric delay correction number remaining after the satellite information mask, the precise orbit and clock difference, the hardware delay deviation and other conventional information are removed. The number of grid points that can be transmitted is estimated by the bit number, and then the broadcasting area covered by the grid points that can be transmitted is calculated from the O point in the circle O along the running direction of the satellite, that is, the first subframe correction number area dynamically divided, which is set as the area surrounded by OAB in the figure. After the above work is completed, the correction number of the first subframe is transmitted. The interval of the subframe data transmission is 1 second, and when the first subframe transmission is completed, the satellite enhanced service coverage range moves to a circle O', and the satellite starts to broadcast the data of the second subframe. The coverage range of the second subframe broadcasting correction number is set as the area surrounded by A'B'CD in Figure 4 According to the above broadcasting rules, the area that cannot be covered by the broadcasting of the required correction number is the area surrounded by AA' and the intersection points of the upper sides of the two circles and the area surrounded by BB' and the intersection points of the lower sides of the two circles. According to the moving speed of the satellite, the distance between O and O' is only less than 7 km, so the area that cannot be covered in practice is almost negligible. Assuming that the correction number broadcasting in all areas in the circle is completed according to the above rules, the coverage area of the satellite is O''. At this time, the next correction number broadcasting cycle starts from the O'' point. In summary, the scheme dynamically divides the broadcasting partition, and the correction number broadcasting coverage area of each frame and each subframe is different, and the data amount is also different.

[0058] Design of the expression format of the atmospheric delay correction number:

[0059] The official standard format of the PPP-RTK correction number is RTCM 10403.2. For the broadcasting mode of the low-orbit satellite PPP-RTK correction number, a plurality of adaptive improvements need to be made on the standard format. In the improved low-orbit enhanced correction number information format design of the application, the atmospheric delay correction number module, that is, the correction number information, is divided into four parts: the header file, the grid point information, the troposphere correction number part and the oblique ionosphere correction number part. The content and capacity requirement of the header file are shown in Table 1.

[0060] Table 1 Content and capacity requirement of the header file

[0061] Content Threshold Bit number RTCM correction type 0～15 4 Seconds of hour 0～3599 12 Tropospheric correction availability 0～1 1 Ionospheric correction availability 0～1 1

[0062] (1) RTCM correction type

[0063] Refer to RTCM 10403.2 for correction type definition.

[0064] (2) seconds of hour

[0065] BDT time seconds of hour.

[0066] (3) troposphere correction availability

[0067] "0" means the data part does not contain troposphere correction; "1" means it contains.

[0068] (4) ionosphere correction availability

[0069] "0" means the data part does not contain ionosphere correction; "1" means it contains.

[0070] Grid point information

[0071] This part gives all grid points that broadcast valid corrections in this module. The ionosphere and troposphere delay correction parts broadcast grid point data in order according to the internal grid point number in this section. Table 2 gives the format and capacity requirements of grid point information. Type I grid points refer to grid points whose number difference with the initial grid point number is less than 10. Since the initial grid point number is the smallest among all grid point numbers, there are at most 9 type I grid points, so the threshold is 1-9. Type II grid points refer to grid points whose number difference with the initial grid point number is less than 100, and there are at most 99 type II grid points. Type III grid points refer to grid points whose number difference with the initial grid point number is less than 1000, and there are at most 999 type III grid points. Type IV grid points refer to grid points whose number difference with the initial grid point number is greater than 1000 and less than 2000, and there are at most 999 type IV grid points. Due to the coverage of satellite correction broadcast, the case where the grid point number difference with the initial grid point number is greater than 1999 is impossible.

[0072] Table 2 Grid point information format and capacity requirement table

[0073]

[0074] (1) Internal number

[0075] The grid points that need to be broadcast are renumbered from 1 according to the size of the grid point number. The internal number corresponds to the grid point number one by one, and the maximum value of the internal number is 99.

[0076] (2) Internal number direction

[0077] The number direction is along the meridian direction and along the latitude direction, respectively represented by "0" and "1". When the acute angle between the satellite running direction and the latitude is less than or equal to 45°, the number is along the latitude direction; when the acute angle is greater than 45°, the number is along the meridian direction. As shown in Figure 5 , according to the different running directions of the two satellites, the areas A and B adopt different numbering methods along the latitude and along the longitude, respectively. Figure 5 The acute angle between the satellite running direction of area A and the latitude is less than or equal to 45°, so the number is along the latitude direction from the initial grid point position, and the first three grid point numbers are as follows Figure 5 ; the acute angle between the satellite running direction of area B and the latitude is greater than or equal to 45°, so the number is along the meridian direction, and the first three grid point numbers are as follows Figure 5 .

[0078] (3) Grid level

[0079] "0" is the first level grid, and "1" is the first level and second level grid.

[0080] (4) Initial grid point number

[0081] This module needs to broadcast the number value of the smallest grid point in all grid points.

[0082] (5) Type I grid point number

[0083] This module needs to broadcast the number of type I grid points. Type I grid points refer to grid points whose number difference from the initial grid point number is less than 10.

[0084] (6) Type I grid point

[0085] The difference between type I grid points and the initial grid point number is given in sequence, and the field length is determined by the type I grid point number.

[0086] (7) Type II grid point number

[0087] This module needs to broadcast the number of type II grid points. Type II grid points refer to grid points whose number difference from the initial grid point number is less than 100.

[0088] (8) Type II grid point

[0089] The difference between type II grid points and the initial grid point number is given in sequence, and the field length is determined by the type II grid point number.

[0090] (9) Type III grid point number

[0091] This module needs to broadcast the number of type III grid points. Type III grid points refer to grid points whose number difference from the initial grid point number is less than 1000.

[0092] (10) Type III grid point number

[0093] The difference between the type III grid point and the initial grid point number is given in sequence, and the field length is determined by the type III grid point number.

[0094] (11) Type IV grid point number

[0095] The type IV grid point number is required to be broadcast by this module. The type IV grid point refers to the grid point whose number difference from the initial grid point number is greater than 1000 and less than 2000.

[0096] (12) Type IV grid point

[0097] The value of the difference between the type IV grid point and the initial grid point number minus 1000 is given in sequence, and the field length is determined by the type IV grid point number.

[0098] Tropospheric correction number

[0099] The zenith tropospheric correction number is composed of two parts, the fitting value and the residual value. The correction number information will first indicate the temporary subnetwork area, give the fitting coefficient of the subnetwork, and then give the residual of each grid point, and the format is shown in Table 3.

[0100] Table 3 Tropospheric correction number information format and capacity requirement table

[0101]

[0102]

[0103] (1) Data resolution

[0104] Bit data increases or decreases by 1, the increase or decrease amplitude of the data represented, that is, the resolution of the data.

[0105] (2) Temporary subnetwork number

[0106] The number of subnetworks divided by the end grid point of each subnetwork.

[0107] (3) End grid point internal number

[0108] The end flag of the temporary subnetwork as shown in Figure 6 , assuming that the internal numbers of the three temporary subnetwork end grid points are 11, 21 and 27, then the area A is divided into three subnetworks with internal numbers 1-11, 12-21 and 22-27. Each subnetwork publishes a set of fitting coefficients, and gives the residual value of each grid point in the network except the fitting value.

[0109] (4) Tropospheric fitting coefficient

[0110] The formula for calculating the fitting model value according to the fitting coefficients is

[0111] ΔT = T 00 + T 01 (φ - φ0) + T 10 (λ - λ0)

[0112] wherein φ and λ are the longitude and latitude of the point to be calculated, φ0 and λ0 are the longitude and latitude of the temporary sub-network end grid point, and ΔT is the troposphere delay fitting value; T 00 and T 10 are the 0th and 1st order fitting coefficients, respectively.

[0113] (5) Troposphere residual

[0114] The residual value of each grid point after removing the fitting model value is given in order according to the internal number of all grid points, a total of , with a resolution of 0.004 meters.

[0115] Slant ionosphere correction

[0116] The slant ionosphere correction is also composed of a fitting value and a residual value. The ionosphere and troposphere corrections share the temporary sub-network division method. The information format is shown in Table 4.

[0117] Table 4 Information format and capacity requirement table of slant ionosphere correction

[0118]

[0119]

[0120] (1) Ionosphere data quality warning symbol

[0121] The satellite order is given by the satellite mask information.

[0122] (2) Ionosphere fitting coefficients

[0123] C 00 The coefficient resolution is 0.05 TECU, C 01 and C 10 The coefficient resolution is 0.02 TECU / deg.

[0124] Step 103: uploading the correction information to the injection station to control the satellite to broadcast the correction information through the injection station.

[0125] As Figure 3As shown, in actual application, after the uploading of the correction information to the injection station to control the satellite broadcasting of the correction information by the injection station, it further comprises: the injection station sends the correction information to the satellite within the field of view of the injection station; the satellite within the field of view of the injection station transmits the correction information to the satellite outside the field of view of the injection station through inter-satellite link data communication.

[0126] According to the design format of Table 1 to Table 4, the specific content of the broadcasting information of each satellite is organized, the data is transmitted to the injection station, and the injection station is uploaded to a satellite within the field of view. The correction information of each satellite is transmitted to the designated satellite through inter-satellite link data communication. Each satellite broadcasts the PPP-RTK correction number to provide enhanced services to the user under the satellite.

[0127] The present application mainly solves the problem of implementing the method for broadcasting the PPP-RTK correction number of the Chinese multi-GNSS system by the low-orbit navigation satellite. The present application can solve the problems of satellite bandwidth allocation, correction number regional division and correction number data format coding for broadcasting the atmospheric delay correction number of the low-orbit satellite. The present application provides a set of grid points with fixed coordinates covering the whole country, flexibly determines the broadcasting data partition according to the running direction and coverage area of the satellite, and broadcasts according to the simplified data format designed by the present application, so as to reduce the satellite bandwidth occupation as much as possible.

[0128] The present application has the following advantages:

[0129] Firstly, the population and service usage rate difference is considered when designing the atmospheric delay grid points covering the whole country.

[0130] When designing the atmospheric delay correction number grid points covering the whole country, the population difference between the east and west is considered, the fact that the ionosphere in the southern region is more active and the error is more significant is considered, and the grid is encrypted in the key city area. The design effect can reduce the occupation of satellite broadcasting bandwidth resources by invalid grid points and unnecessary grid points as much as possible on the premise of ensuring the positioning quality of the area with high service usage rate and high service accuracy requirement.

[0131] Secondly, the correction number broadcasting mode with adjustable coverage range and partition block broadcasting is designed.

[0132] The atmospheric delay correction number service coverage area determined according to the cut-off height angle is designed through overall planning of the satellite signal overlapping coverage area, which is significantly reduced compared with the satellite signal coverage area, thereby reducing the necessary broadcasting data amount of each satellite without affecting the service quality. The designed broadcasting mode of real-time partition block broadcasting along the running direction of the satellite guarantees the integrity and timeliness of the correction number broadcasting of the service coverage area to the greatest extent.

[0133] Thirdly, the PPP-RTK atmospheric delay correction data format suitable for low-orbit satellite broadcasting is designed.

[0134] For the low-orbit satellite broadcasting mode, the expression format of the SSR form of the PPP-RTK atmospheric delay correction number is improved so as to be suitable for the low-orbit navigation satellite broadcasting of the atmospheric delay correction number information of the ground pre-defined grid points.

[0135] The application also provides a PPP-RTK correction number broadcasting system, comprising:

[0136] The acquisition module is used to acquire the grid point information.

[0137] The correction number information determination module is used to determine the correction number information according to the satellite running direction, the satellite signal coverage area and the grid point information in a dynamic partition block manner; the correction number information comprises a header file, the grid point information, troposphere correction number and oblique ionosphere correction number.

[0138] The uploading module is used to upload the correction number information to an injection station so as to control the satellite broadcasting of the correction number information through the injection station.

[0139] As an optional implementation manner, the acquisition module specifically comprises:

[0140] The grid deployment principle determination unit is used to determine the grid deployment principle according to the population difference of the region and the meridian of the region;

[0141] The grid point information determination unit is used to determine the grid point information according to the grid deployment principle and the ionosphere area of the region.

[0142] The application utilizes the low-orbit navigation satellite broadcasting of the atmospheric delay correction number product to improve the positioning precision and convergence speed of the flow station. Firstly, a two-stage atmospheric delay grid point deployment scheme is designed according to the ionosphere error space variation and the enhanced service utilization rate; secondly, in order to reduce the data broadcasting pressure and fully utilize the bandwidth resources of the low-orbit satellite, a broadcasting strategy with real-time adjustable service coverage range is established; then, a sub-area partition method of the data block according to the in-frame data amount is designed; finally, the corresponding correction number data format is improved for the designed broadcasting mode. The application designs a broadcasting mode of the PPP-RTK correction number of the low-orbit satellite, and simultaneously reduces the requirement for the broadcasting bandwidth according to the broadcasting partition optimization and format improvement, and has the characteristics of small bandwidth occupation, wide service range, strong service area expandability and the like.

[0143] The various embodiments described in this specification are presented for the purpose of illustrating the principles of the present application and its best mode of operation. Each of the embodiments described in this specification has been provided for the purpose of illustration only and the various embodiments are not intended to limit the present application in any way unless otherwise specifically indicated. The same parts and / or features of the various embodiments described in this specification can be referenced using the same reference numerals for the ease of understanding of the present application.

[0144] The principles and implementations of the present application have been described above with the specific examples. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, the specific implementation and application range of the present application can be changed according to the idea of the present application. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A method for broadcasting PPP-RTK correction numbers, characterized in that, The method comprises the following steps: acquiring grid point information; the acquiring grid point information specifically comprises: determining a grid deployment principle according to population differences of a region and meridians of the region; and determining grid point information according to the grid deployment principle and ionosphere regions of the region; determining correction number information according to a satellite running direction and a satellite signal coverage region and the grid point information in a dynamic partition block mode; the correction number information comprises a header file, the grid point information, troposphere correction numbers and oblique ionosphere correction numbers; key points of a partition block broadcasting mode design method comprise: satellite service region coverage lobe angle design of a correction number service coverage range adjustable satellite service region; a correction number region partition block method in a cross-sweeping mode along the satellite running direction, wherein a partition size is determined by a bandwidth of subframe broadcastable resources; uploading the correction number information to an injection station to control a satellite to broadcast the correction number information through the injection station.

2. The PPP-RTK correction broadcast method of claim 1, wherein, The dynamic partition block mode is specifically a cross-sweeping mode along the satellite running direction.

3. The PPP-RTK correction broadcasting method of claim 1, wherein, The troposphere correction numbers comprise troposphere fitting values and troposphere residual values; and the oblique ionosphere correction numbers comprise oblique ionosphere fitting values and oblique ionosphere residual values.

4. The PPP-RTK correction broadcasting method of claim 3, wherein, An expression of the troposphere fitting value is: ΔT = T 00 + T 01 (φ - φ0) + T 10 (λ - λ0) Wherein, φ and λ are the longitude and latitude of the point to be calculated, φ0 and λ0 are the longitude and latitude of the temporary sub-network ending grid point, ΔT is the tropospheric delay fitting value; T 00 and T 10 are 0 order and 1 order fitting coefficients respectively.

5. The PPP-RTK correction broadcasting method of claim 1, wherein, after the uploading of the correction number information to the injection station to control the satellite to broadcast the correction number information through the injection station, the method further comprises the following steps: the injection station sends the correction number information to a satellite within a field of view of the injection station; the satellite within the field of view of the injection station transmits the correction number information to a satellite outside the field of view of the injection station through inter-satellite link data communication.

6. A PPP-RTK correction number broadcasting system, characterized in that, The method comprises the following steps: an acquiring module is configured to acquire grid point information; the acquiring module specifically comprises: a grid deployment principle determination unit configured to determine a grid deployment principle according to population differences of a region and meridians of the region; and a grid point information determination unit configured to determine grid point information according to the grid deployment principle and ionosphere regions of the region; a correction number information determination module is configured to determine correction number information according to a satellite running direction and a satellite signal coverage region and the grid point information in a dynamic partition block mode; the correction number information comprises a header file, the grid point information, troposphere correction numbers and oblique ionosphere correction numbers; key points of a partition block broadcasting mode design method comprise: satellite service region coverage lobe angle design of a correction number service coverage range adjustable satellite service region; a correction number region partition block method in a cross-sweeping mode along the satellite running direction, wherein a partition size is determined by a bandwidth of subframe broadcastable resources; an uploading module is configured to upload the correction number information to an injection station to control a satellite to broadcast the correction number information through the injection station.

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