Navigation information deconstruction and recoding method and device based on GNSS service information enhancement

Abstract

A method and device for deconstructing and recoding navigation information based on GNSS service information enhancement relates to the field of global navigation satellite systems. In view of the problem in the prior art that for navigation applications related to life safety, the system side needs to provide integrity information of enhanced data; and so far, there is no open, industry-recognized standard to support the minimum bandwidth requirements required for PPP-RTK applications, and provide integrity information for navigation applications related to life safety, the technical solution provided by the present invention is: a method for deconstructing and recoding navigation information based on GNSS service information enhancement, the method comprising: step 1: enhancing the GNSS service information data of the navigation information; step 2: formatting and optimizing the bandwidth of the enhanced GNSS service information; step 3: outputting the processing result of step 2 as the recoding result. It is suitable for use in the research of navigation related to life safety, and can also be used in the processing of maritime navigation information.

Description

Technical Field

[0001] It relates to the field of global navigation satellite systems and, more specifically, to maritime navigation information. Background Art

[0002] Real-Time Kinematic (RTK) and Precise Point Positioning (PPP) are the most widely used and representative technologies in GNSS high-precision positioning. Among them, PPP technology, which features state domain spatial error correction, has a wide coverage, but a long convergence time; network RTK technology, which features densely deployed stations, converges quickly, but has a small service range. Therefore, PPP-RTK technology, which combines the advantages of the above two technologies, came into being.

[0003] At present, Japan's Quasi-Zenith Satellite System (QZSS) has taken the lead in implementing satellite-based PPP-RTK enhanced service CLAS based on L6D signals, with a data broadcast rate of 2000bps and a service coverage of Japan. In addition, some commercial companies have also begun to provide PPP-RTK services, such as Trimble's CenterPoint RTX service, NovAtel's TerraStar-X service, Fugro's Marinstar G4+ service, and GEO++'s SSRPOST service. Although the above commercial services involve PPP-RTK applications, there is little public information available for reference on the encoding format and broadcasting scheme of PPP-RTK services.

[0004] The demand for GNSS satellite-based augmentation services in marine applications is increasing. To achieve signal augmentation services for marine applications, bandwidth limitations of the communication link are one of the key issues. This problem is exacerbated by the introduction of multiple GNSS systems and regional atmospheric correction information. And for navigation applications related to life safety, the system needs to provide integrity information of the augmentation data. So far, there is no open, industry-recognized standard that supports the minimum bandwidth requirements required for PPP-RTK applications while providing integrity information for navigation applications related to life safety.

[0005] In summary, it is of great significance to invent a deconstruction and recoding method based on GNSS enhanced service information. Summary of the invention

[0006] In view of the problem that navigation applications related to life safety in the prior art require the system to provide integrity information of enhanced data; and so far, there is no open, industry-recognized standard to support the minimum bandwidth requirements required for PPP-RTK applications, and provide integrity information for navigation applications related to life safety, the technical solution provided by the present invention is:

[0007] A navigation information deconstruction and recoding method based on GNSS service information enhancement, the method comprising:

[0008] Step 1: enhancing the GNSS service information data of the navigation information;

[0009] Step 2: Format compression and bandwidth optimization of the enhanced GNSS service information;

[0010] Step 3: Output the processing result of step 2 as the re-encoding result.

[0011] Further, a preferred embodiment is provided, wherein step 1 further comprises:

[0012] Step 1.1: Collect the preset correction information change rate;

[0013] Step 1.2: Expand regional atmospheric correction information;

[0014] Step 1.3: Collect the preset integrity indicators.

[0015] Furthermore, a preferred embodiment is provided, wherein the regional atmospheric correction information in step 1.2 includes: regional ionosphere information and regional troposphere information.

[0016] Further, a preferred embodiment is provided, wherein step 2 further comprises:

[0017] Step 2.1: Describe the changes of the correction information of the enhanced GNSS service information data in a compact format.

[0018] Based on the same inventive concept, the present invention also provides a navigation information deconstruction and recoding device based on GNSS service information enhancement, the device comprising:

[0019] Module 1: used to enhance the GNSS service information data of the navigation information;

[0020] Module 2: used to compress the format and optimize the bandwidth of enhanced GNSS service information;

[0021] Module 3: used to output the processing result of step 2 as the re-encoding result.

[0022] Further, a preferred embodiment is provided, wherein the module 1 further comprises:

[0023] Module 1.1: used to collect the preset correction information change rate;

[0024] Module 1.2: used to expand regional atmospheric correction information;

[0025] Module 1.3: Used to collect preset integrity indicators.

[0026] Furthermore, a preferred embodiment is provided, wherein the regional atmospheric correction information in the module 1.2 includes: regional ionosphere information and regional troposphere information.

[0027] Further, a preferred embodiment is provided, wherein the module 2 further comprises:

[0028] Module 2.1: used to describe the changes of the correction information of the enhanced GNSS service information data in a compact format.

[0029] Based on the same inventive concept, the present invention also provides a computer storage medium for storing a computer program. When a computer processor processes the computer program in the storage medium, the computer executes the navigation information deconstruction and recoding method based on GNSS service information enhancement.

[0030] Based on the same inventive concept, the present invention also provides a computer, including a processor and a storage medium, wherein the storage medium stores a computer program. When the processor of the computer processes the computer program in the storage medium, the computer executes the navigation information deconstruction and recoding method based on GNSS service information enhancement.

[0031] The present invention is beneficial in that:

[0032] The navigation information deconstruction and recoding method based on GNSS service information enhancement provided by the present invention is aimed at the problem that the GNSS enhanced service information data volume of PPP-RTK service application is large and no regional atmospheric integrity information is provided. The present invention proposes a deconstruction and recoding method of GNSS enhanced service information, which can ensure the service performance and integrity of the user terminal under the condition of restricted sea communication.

[0033] It is suitable for use in research on navigation related to life safety, and can also be used in the processing of marine navigation information. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of the navigation information deconstruction and recoding method based on GNSS service information enhancement mentioned in the eleventh implementation mode. DETAILED DESCRIPTION

[0035] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail with reference to the accompanying drawings, specifically:

[0036] Embodiment 1: This embodiment provides a navigation information deconstruction and recoding method based on GNSS service information enhancement. The method includes:

[0037] Step 1: enhancing the GNSS service information data of the navigation information;

[0038] Step 2: Format compression and bandwidth optimization of the enhanced GNSS service information;

[0039] Step 3: Output the processing result of step 2 as the re-encoding result.

[0040] Specifically,

[0041] Step 1 includes providing the rate of change of correction information to improve the stability of GNSS services in the sea under slow update conditions; expanding regional atmospheric correction information, including regional ionosphere information and regional troposphere information, to support PPP-RTK services; providing integrity indicators of various correction information to support integrity monitoring of the user end and ensure the integrity requirements of the user end;

[0042] Step 2 includes describing the changes in various correction information of GNSS augmentation service data in a compact format and ensuring service performance for marine users under slow update conditions of augmentation service data; maintaining compatibility with existing RTCM standards; and being flexible enough to support existing and future GNSS signals.

[0043] Implementation method 2: This implementation method further limits the navigation information deconstruction and recoding method based on GNSS service information enhancement provided in implementation method 1, and step 1 further includes:

[0044] Step 1.1: Collect the preset correction information change rate;

[0045] Step 1.2: Expand regional atmospheric correction information;

[0046] Step 1.3: Collect the preset integrity indicators.

[0047] Implementation method three: This implementation method is a further limitation of the navigation information deconstruction and recoding method based on GNSS service information enhancement provided in implementation method two, and the regional atmospheric correction information in step 1.2 includes: regional ionosphere information and regional troposphere information.

[0048] Embodiment 4: This embodiment further limits the navigation information deconstruction and recoding method based on GNSS service information enhancement provided in any one of embodiments 1 to 3, and step 2 further includes:

[0049] Step 2.1: Describe the changes of the correction information of the enhanced GNSS service information data in a compact format.

[0050] Embodiment 5: This embodiment provides a navigation information deconstruction and recoding device based on GNSS service information enhancement, the device comprising:

[0051] Module 1: used to enhance the GNSS service information data of the navigation information;

[0052] Module 2: used to compress the format and optimize the bandwidth of enhanced GNSS service information;

[0053] Module 3: used to output the processing result of step 2 as the re-encoding result.

[0054] Embodiment 6: This embodiment is a further limitation of the navigation information deconstruction and recoding device based on GNSS service information enhancement provided in Embodiment 5, wherein the module 1 further includes:

[0055] Module 1.1: used to collect the preset correction information change rate;

[0056] Module 1.2: used to expand regional atmospheric correction information;

[0057] Module 1.3: Used to collect preset integrity indicators.

[0058] Implementation method seven: This implementation method is a further limitation on the navigation information deconstruction and re-encoding device based on GNSS service information enhancement provided in implementation method six. The regional atmospheric correction information in module 1.2 includes: regional ionosphere information and regional troposphere information.

[0059] Embodiment 8: This embodiment further limits the navigation information deconstruction and recoding device based on GNSS service information enhancement provided in embodiments 5 to 7, and the module 2 further includes:

[0060] Module 2.1: used to describe the changes of the correction information of the enhanced GNSS service information data in a compact format.

[0061] Implementation method nine: This implementation method provides a computer storage medium for storing a computer program. When a computer processor processes the computer program in the storage medium, the computer executes the navigation information deconstruction and recoding method based on GNSS service information enhancement provided in implementation method four.

[0062] Implementation method ten: This implementation method provides a computer, including a processor and a storage medium, wherein the storage medium stores a computer program. When the processor of the computer processes the computer program in the storage medium, the computer executes the navigation information deconstruction and recoding method based on GNSS service information enhancement provided in implementation method four.

[0063] Implementation eleven: This implementation provides a specific implementation for the navigation information deconstruction and recoding method based on GNSS service information enhancement provided in Implementation four, and is also used to explain Implementations one to four, specifically:

[0064] Step 1: GNSS service information data enhancement:

[0065] Due to the high frequency of the onboard atomic clock, the satellite clock error has a greater impact on positioning performance than other differential correction information, and the satellite clock error correction information provided by most real-time data streams only contains the C0 parameter, and the C1 and C2 parameters are set to 0. For terrestrial services, the communication bandwidth is large and the transmission stability is high, and the service requirements can be fully met through a high update frequency. However, due to limited communications in the marine environment, the update frequency of GNSS service data is low. In order to meet the established service requirements, it is necessary to broadcast the C1 and C2 parameters of the satellite clock error correction information in the GNSS service data to ensure service performance under slow update conditions of marine service data. For other correction information of GNSS service data, the corresponding correction information change rate can be provided according to its temporal and spatial characteristics to meet the positioning performance requirements of marine PPP-RTK services.

[0066] For the regional ionospheric correction information in the atmospheric delay correction information, the polynomial parameters related to the longitude and latitude of the service area and the grid point parameters are broadcast. The polynomial parameters are broadcast in the regional ionospheric correction information flow, while the grid point parameters and the tropospheric grid point parameters are combined and broadcast in the regional tropospheric correction information flow, which can reduce data redundancy and alleviate the pressure on maritime communications.

[0067] In addition to the clock and orbit correction information, GNSS service data are also attached with deviation B value, QI information and prior probability Pf. The B value, QI information and prior probability Pf of the satellite clock and orbit correction information are broadcast separately. Among them, for the satellite-related spatial geometry correction information, the prior probability Pf that does not distinguish between satellites is added to the corresponding message data header, and the B value and QI information that distinguish between satellites are added after each satellite correction information in the message data body; for the satellite-independent atmospheric delay correction information, the B value, QI and prior probability Pf are added to the corresponding message data header. For the GNSS service data before broadcasting, it is defaulted to be available at the time of broadcasting, and the availability mark is not broadcast to the user; after the broadcast, the GNSS service data is monitored a posteriori, and the user is promptly alerted to the abnormal correction information, and the availability mark of the abnormal correction information is separately appended.

[0068] Step 2: GNSS service information format compression and bandwidth optimization:

[0069] Masks - satellite masks, signal masks and cell masks. The deconstructed re-encoded GNSS service data does not distinguish between GNSS systems, and the same type of correction information of each GNSS system is merged into the same message for broadcast. The satellite mask is used to distinguish the correction information and integrity information related to the satellite, such as satellite orbit, satellite clock correction information and clock orbit integrity information. The signal mask and cell mask are used to determine the code deviation information and phase deviation information that need to be broadcast, which can effectively reduce the data volume of GNSS service information.

[0070] Among them, the satellite mask range is 0-59, corresponding to the PRN number of each GNSS system satellite. When the corresponding flag bit is 1, it indicates that the system has correction information related to the corresponding satellite, such as satellite orbit correction information, satellite clock correction information and clock orbit integrity information; the signal mask range is 0-15, corresponding to the navigation service signal of each GNSS system. When the corresponding flag bit is 1, it indicates the collection of all satellite signals whose satellite mask flag bit is 1; the unit mask range is determined according to the number of signal masks, indicating the specific signal subset of the corresponding satellite. When the corresponding flag bit is 1, it indicates that there is corresponding signal deviation correction information, such as code deviation correction information, phase deviation correction information and corresponding integrity information.

[0071] Variable length - The length of the deconstructed re-encoded GNSS service data is variable. The spatial geometry correction information in the GNSS service data is based on the satellite mask, signal mask and unit mask provided by the mask information. Only the spatial geometry correction information with the corresponding flag bit of 1 is broadcast. For the spatial geometry correction information with the flag bit of 0, the corresponding valid data bit is not retained. The processing strategy of atmospheric delay correction information and integrity information is the same as above.

[0072] Relative deviation - describes the systematic difference in satellite signal delays between different signals of the same frequency, avoiding the use of absolute value transmission in real-time data. Relative deviation mainly refers to the code deviation and phase deviation in the differential correction information of the GNSS service. Generally speaking, the code deviation and phase deviation in the RTCM SSR broadcast the absolute value of the signal deviation, which is relatively close in value. Therefore, for the PPP-RTK service, the deconstruction and re-encoding format adopts the strategy of merging and broadcasting the code deviation and the phase deviation. With the code deviation as the benchmark, the phase deviation only broadcasts the difference between the same-frequency code deviation and the original phase deviation, which can reduce the effective number of bits of the integer part of the phase deviation and the redundancy of the data header, effectively reducing data throughput and optimizing bandwidth.

[0073] Effective number of bits - Determine the impact of the effective number of bits of each GNSS service data on the performance of the required services at sea, and reduce the effective number of bits in its transmission. Conduct a large number of experiments and simulations, analyze the impact of the effective number of bits of various correction information on positioning performance by changing the effective number of bits of each type of service data, and optimize the effective number of bits of GNSS service data broadcast while meeting the PPP-RTK service requirements.

[0074] Lossless compression coding - compresses and deconstructs the real-time data stream in a re-encoded format to further optimize bandwidth. The compressed GNSS service data is re-encoded using the Rice coding algorithm, which further reduces data throughput through lossless data compression, optimizing maritime communication bandwidth and transmission efficiency.

[0075] The navigation information deconstruction and recoding method based on GNSS service information enhancement provided by the present invention integrates and optimizes various types of PPP-RTK enhanced service information and corresponding integrity information to generate compact enhanced service data, optimizes the communication link bandwidth and improves the user-side integrity monitoring performance, and provides an enhanced service information coding protocol for the system end for sea users.

[0076] The several specific implementation modes described above are intended to highlight the advantages and benefits of the technical solutions provided by the present invention and are not intended to be used as limitations on the present invention. Any modifications and improvements to the technical solutions provided by the present invention, improvements and combinations of the implementation modes, etc., based on the spirit and principles of the present invention, should be included in the scope of protection of the present invention.

Claims

1. A navigation information deconstruction and recoding method based on GNSS service information enhancement, characterized in that: The method comprises: Step 1: enhancing the GNSS service information data of the navigation information; Step 2: Format compression and bandwidth optimization of the enhanced GNSS service information; Step 3: Output the processing result of step 2 as the re-encoding result; Specifically, Step 1 includes providing the rate of change of correction information; expanding regional atmospheric correction information, including regional ionosphere information and regional troposphere information; providing integrity indicators of various correction information; Among them, in addition to the clock and orbit correction information, the GNSS service data are all attached with the deviation B value, QI information and prior probability Pf; the B value, QI information and prior probability Pf of the satellite clock and orbit correction information are broadcast separately, and the satellite-related spatial geometry correction information is added to the corresponding message data header. The satellite-indistinguishable prior probability Pf is added after each satellite correction information in the message data body. The satellite-indistinguishable B value and QI information are added to the corresponding message data header for the atmospheric delay correction information that is not related to the satellite. For the GNSS service data before broadcasting, it is assumed to be available at the time of broadcasting, and the availability mark is not broadcast to the user. After the broadcast, the GNSS service data is monitored a posteriori, and the user is promptly warned of the abnormal correction information, and the availability mark of the abnormal correction information is separately appended; Step 2 involves describing all correction changes in GNSS augmentation service data in a compact format; maintaining compatibility with existing RTCM standards; and being configured to support existing and future GNSS signals; Among them, the satellite mask range is 0-59, corresponding to the PRN number of each GNSS system satellite. When the corresponding flag bit is 1, it indicates that the system has correction information related to the corresponding satellite, specifically: satellite orbit correction information, satellite clock correction information and clock-orbit integrity information; the signal mask range is 0-15, corresponding to the navigation service signal of each GNSS system. When the corresponding flag bit is 1, it indicates the collection of all satellite signals whose satellite mask flag bit is 1; the unit mask range is determined according to the number of signal masks, indicating the specific signal subset of the corresponding satellite. When the corresponding flag bit is 1, it indicates that there is corresponding signal deviation correction information.

2. A navigation information deconstruction and recoding device based on GNSS service information enhancement, characterized in that: The device comprises: Module 1: used to enhance the GNSS service information data of the navigation information; Module 2: used to compress the format and optimize the bandwidth of enhanced GNSS service information; Module 3: used to output the processing result of module 2 as the re-encoding result; Specifically, Module 1 is implemented by providing the rate of change of correction information; expanding regional atmospheric correction information, including regional ionosphere information and regional troposphere information; and providing integrity indicators of various correction information; Among them, in addition to the clock and orbit correction information, the GNSS service data are all attached with the deviation B value, QI information and prior probability Pf; the B value, QI information and prior probability Pf of the satellite clock and orbit correction information are broadcast separately, and the satellite-related spatial geometry correction information is added to the corresponding message data header. The satellite-indistinguishable prior probability Pf is added after each satellite correction information in the message data body. The satellite-indistinguishable B value and QI information are added to the corresponding message data header for the atmospheric delay correction information that is not related to the satellite. For the GNSS service data before broadcasting, it is assumed to be available at the time of broadcasting, and the availability mark is not broadcast to the user. After the broadcast, the GNSS service data is monitored a posteriori, and the user is promptly warned of the abnormal correction information, and the availability mark of the abnormal correction information is separately appended; Module 2 is implemented by describing all correction information changes in GNSS augmentation service data in a compact format; maintaining compatibility with existing RTCM standards; and being configured to support existing and future GNSS signals; Among them, the satellite mask range is 0-59, corresponding to the PRN number of each GNSS system satellite. When the corresponding flag bit is 1, it indicates that the system has correction information related to the corresponding satellite, specifically: satellite orbit correction information, satellite clock correction information and clock-orbit integrity information; the signal mask range is 0-15, corresponding to the navigation service signal of each GNSS system. When the corresponding flag bit is 1, it indicates the collection of all satellite signals whose satellite mask flag bit is 1; the unit mask range is determined according to the number of signal masks, indicating the specific signal subset of the corresponding satellite. When the corresponding flag bit is 1, it indicates that there is corresponding signal deviation correction information.

3. A computer storage medium for storing a computer program, characterized in that: When the processor of the computer processes the computer program in the storage medium, the computer executes the navigation information deconstruction and recoding method based on GNSS service information enhancement as described in claim 1.

4. A computer, comprising a processor and a storage medium, wherein the storage medium stores a computer program, characterized in that: When the processor of the computer processes the computer program in the storage medium, the computer executes the navigation information deconstruction and recoding method based on GNSS service information enhancement as described in claim 1.

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