A satellite-based RTK positioning enhancement method and system based on short message communication

Abstract

This invention provides a satellite-based RTK positioning enhancement method and system based on short message communication, comprising: a reference station collecting data to obtain a set of positioning observations; performing common error calculation and modeling on the set of positioning observations to obtain observation correction values; constructing a reference station update query list, encoding the observation correction values, and generating a binary data stream; based on the encoding format, packetizing and broadcasting the binary data stream into short messages, and sending it to a target user station; the target user station receiving the binary data stream and calculating its location coordinates. This invention utilizes the BeiDou satellite-based link to achieve global RTK service coverage, solving the biggest application bottleneck of traditional RTK. Through a common error modeling deduction + residual error high-resolution encoding strategy, the amount of RTK enhancement information data per epoch is compressed to an extremely low level, perfectly adapting to the limited bandwidth of BeiDou short messages.

Description

Technical Field

[0001] This invention relates to the field of navigation and positioning technology, and in particular to a satellite-based RTK positioning enhancement method and system based on short message communication. Background Technology

[0002] Real-Time Kinematic (RTK) technology provides centimeter-level high-precision positioning services to user stations by receiving carrier phase observation correction information broadcast by a reference station. However, traditional RTK technology heavily relies on stable, continuous terrestrial mobile communication networks (such as 4G / 5G) or dedicated data links for differential information transmission. In remote areas with weak or absent terrestrial network signal coverage, such as oceans, deserts, and mountains, and in emergency scenarios where terrestrial communication facilities are damaged due to earthquakes or floods, traditional RTK technology fails due to the inability to obtain real-time correction information, severely limiting its application scope. Its core technical solutions are typically based on two mainstream modes: "terrestrial data communication link" and "observation domain correction" or "state domain correction." Conventional RTK technology based on terrestrial communication links is the most widely used RTK mode. Its technical solution mainly includes the following steps: (1) Reference station network: One or more GNSS reference stations with known precise coordinates are deployed within the service area (usually a city, project area, etc.).

[0003] (2) Data acquisition and generation: The reference station continuously receives GNSS satellite signals and generates a data stream containing raw observation values ​​such as pseudorange and carrier phase.

[0004] (3) Data broadcasting: The reference station transmits its original observations or generated differential correction data to users within a certain distance range in real time through the ground wireless communication network.

[0005] (4) User-end positioning calculation: The rover simultaneously receives GNSS satellite signals and differential data from the reference station. The rover receiver adopts a double-difference observation model, which combines its own observations with the reference station's observations to eliminate common errors such as satellite clock error, receiver clock error, ionospheric and tropospheric delays, thereby quickly fixing integer ambiguity and calculating its own coordinates with centimeter-level accuracy.

[0006] Satellite-based augmentation services based on state-domain correction (such as PPP-RTK): To overcome the limitation of short operating range in conventional RTK, technologies have been developed that utilize satellite broadcast channels to broadcast augmentation information. The main technical steps include: (1) Global or regional reference station network: Construct a large-scale ground reference station network.

[0007] (2) Data center processing: The data center collects data from all reference stations and estimates satellite orbital errors, satellite clock errors, phase deviations, and regional ionospheric and tropospheric delays through precise data processing.

[0008] (3) Information broadcasting: These state domain correction parameters are encoded and broadcast through the dedicated navigation enhancement signal link of the geostationary orbit (GEO) communication satellite.

[0009] (4) Precise point positioning at the user end: The user receives satellite signals and SSR correction streams, and uses the correction numbers at the receiver end to precisely correct their observations or positioning models. Precise point positioning (PPP) technology is used, which usually requires a long convergence time (several minutes to tens of minutes) to fix the ambiguity, and finally achieves centimeter to decimeter level positioning.

[0010] The above technology has the following drawbacks: (1) Service coverage is heavily dependent on ground infrastructure: In areas such as oceans, deserts, deep mountains, and remote border regions where ground networks cannot cover or have extremely poor signals, the technology is completely ineffective or its performance drops sharply, resulting in huge service blind spots.

[0011] (2) The communication link is vulnerable: the radio used is susceptible to terrain obstruction and electromagnetic interference, and the communication distance is limited; the mobile public network on which it relies may fail during natural disasters (such as earthquakes and floods) or special events, posing a risk in scenarios with high reliability requirements such as emergency rescue.

[0012] (3) The challenge of achieving “fast, reliable and high precision”: “fast and high precision” (instantaneous centimeter level) can be achieved within the coverage area, but “reliability” is limited by the ground communication link.

[0013] In addition to providing positioning, navigation, and timing (PNT) services, the BeiDou Navigation Satellite System boasts unique global short message communication services with advantages such as wide coverage (especially in the Asia-Pacific region), independence from terrestrial networks, and reliable communication. Theoretically, broadcasting RTK augmentation information via short messages could completely eliminate reliance on terrestrial communication, achieving true global / regional wide-area precise positioning. However, short message communication suffers from bandwidth limitations and latency issues, making it impractical to directly transmit traditional RTK data streams via short messages.

[0014] Therefore, there is an urgent need for an efficient data compression and encoding method to significantly compress RTK enhancement information to adapt to the transmission capability of short messages, while ensuring the accuracy of user-end decoding. Summary of the Invention

[0015] This invention provides a satellite-based RTK positioning enhancement method and system based on short message communication to address the deficiencies in the prior art.

[0016] In a first aspect, the present invention provides a satellite-based RTK positioning enhancement method based on short message communication, comprising: The reference station collects data to obtain a set of positioning observations; The common error is calculated and modeled on the set of positioning observations to obtain the observation correction values; Construct a base station update query list, encode the observed value correction values, and generate a binary data stream; Based on the encoding format, the binary data stream is packetized into short messages and broadcast to the target user station; The target user station receives the binary data stream and calculates the target user station's location coordinates.

[0017] According to the present invention, a satellite-based RTK positioning enhancement method based on short message communication is provided, wherein a reference station performs data acquisition to obtain a set of positioning observations, including: The reference station receives raw pseudorange and carrier phase observations from multi-frequency, multi-mode GNSS satellites; Obtain satellite broadcast ephemeris and satellite broadcast clock bias.

[0018] According to the present invention, a satellite-based RTK positioning enhancement method based on short message communication is provided, which performs common error calculation and modeling on the positioning observation set to obtain observation correction values, including: Obtain the carrier observation equation and pseudorange observation equation; The geometric distance between the reference station and the satellite is calculated using the satellite position obtained from the reference station's coordinates and the satellite broadcast ephemeris. The tropospheric delay error was calculated using the Saastamoinen model. The ionospheric delay error was calculated using the Klobuchar ionospheric model. The satellite clock bias is calculated using the satellite clock bias parameters provided by satellite broadcast ephemeris. The receiver clock error is calculated by taking the mean of the residuals from the pseudorange observation equations of multiple satellites. Remove the integer part of the integer ambiguity in the carrier phase observation and retain the fractional part to obtain the processed integer ambiguity; By taking into account the geometric distance between the reference station and the satellite, the tropospheric delay error, the ionospheric delay error, the satellite clock error, the receiver clock error, and the processed integer ambiguity, the residual pseudorange correction and the carrier phase correction are obtained.

[0019] According to the present invention, a satellite-based RTK positioning enhancement method based on short message communication is provided, which constructs a base station update query list, encodes the observed value correction values, and generates a binary data stream, including: The elements of the base station update query list include base station broadcast identifier, base station coordinates, observation time, number of satellites, satellite PRN number, phase correction value and pseudorange correction value. All elements include the corresponding size value, value range, resolution and broadcast mechanism. The base station broadcast identifier includes a no-coordinate update identifier and a coordinate update identifier; The residual pseudorange correction value and carrier phase correction value are encoded according to the updated query list of the base station, and the binary data stream is output.

[0020] According to the present invention, a satellite-based RTK positioning enhancement method based on short message communication, based on an encoding format, assembles and broadcasts the binary data stream into short message packets and sends them to the target user station, including: According to the preset satellite short message communication protocol, the binary data stream is packaged at the application layer. Data packets are broadcast to target user stations within the service area via a pre-defined satellite channel.

[0021] According to the present invention, a satellite-based RTK positioning enhancement method based on short message communication is provided, wherein the target user station receives the binary data stream and calculates the target user station's position coordinates, including: The target user station parses the binary data stream to obtain the reference station coordinates, observation time, residual pseudorange corrections and carrier phase corrections for each satellite; The target user station uses its own GNSS observations, combined with the residual pseudorange correction and carrier phase correction obtained by analysis, and uses a unified spatiotemporal reference to eliminate residual common errors, fix integer ambiguities, and calculate the position coordinates of the target user station.

[0022] Secondly, the present invention also provides a satellite-based RTK positioning enhancement system based on short message communication, comprising: The data acquisition module is used by the reference station to collect data and obtain a set of positioning observation values; The calculation module is used to perform common error calculation and modeling on the set of positioning observations to obtain the observation correction values; The encoding module is used to construct the base station update query list, encode the observed value correction values, and generate a binary data stream. The sending module is used to assemble and broadcast the binary data stream into short messages based on the encoding format and send it to the target user station; The calculation module is used to receive the binary data stream from the target user station and calculate the location coordinates of the target user station.

[0023] Thirdly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the satellite-based RTK positioning enhancement method based on short message communication as described above.

[0024] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the satellite-based RTK positioning enhancement method based on short message communication as described above.

[0025] The satellite-based RTK positioning enhancement method and system based on short message communication provided by this invention have the following beneficial effects: (1) Completely eliminates ground dependence: By utilizing the BeiDou satellite-based link, RTK service coverage is achieved globally / regionally (especially in remote areas, oceans, and airspace), solving the biggest application bottleneck of traditional RTK.

[0026] (2) Efficient correction compression method: By using the strategy of "common error modeling deduction + residual error high-resolution coding", the amount of RTK enhancement information data in a single epoch is compressed to an extremely low level, perfectly adapting to the limited bandwidth of Beidou short message.

[0027] (3) Positioning accuracy guarantee: The broadcast carrier phase correction value retains fractional-week information. Combined with the reference station coordinates, the user station can quickly recover the complete double-difference observation equation, thereby achieving fast and reliable integer ambiguity fixation and ensuring centimeter-level positioning accuracy.

[0028] (4) Strong system robustness: Short message communication has strong anti-interference ability and has obvious advantages in scenarios with extremely high requirements for communication reliability, such as emergency rescue, disaster relief, and national defense security. (5) Wide range of applications: It can be widely used in ocean navigation, resource exploration, precision agriculture, autonomous navigation of unmanned systems, geological disaster monitoring, border patrol and other fields. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1This is one of the flowcharts illustrating the satellite-based RTK positioning enhancement method based on short message communication provided by the present invention; Figure 2 This is the second flowchart of the satellite-based RTK positioning enhancement method based on short message communication provided by the present invention; Figure 3 This is a schematic diagram of the structure of the satellite-based RTK positioning enhancement system based on short message communication provided by the present invention; Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] Figure 1 This is one of the flowcharts illustrating the satellite-based RTK positioning enhancement method based on short message communication provided in this embodiment of the invention, such as... Figure 1 As shown, it includes: Step 100: The reference station collects data to obtain a set of positioning observations; Step 200: Perform common error calculation and modeling on the set of positioning observations to obtain the observation correction values; Step 300: Construct a base station update query list, encode the observed value correction values, and generate a binary data stream; Step 400: Based on the encoding format, the binary data stream is packetized into short messages and broadcast to the target user station; Step 500: The target user station receives the binary data stream and calculates the target user station's location coordinates.

[0033] Specifically, the technical solution route of the embodiments of the present invention is as follows: Figure 2 As shown, it includes: Step S1: Reference station data acquisition and preprocessing.

[0034] The reference station receives raw pseudorange and carrier phase observations from multi-frequency, multi-mode GNSS satellites and acquires information such as satellite broadcast ephemeris and satellite broadcast clock bias.

[0035] Step S2: Common error modeling and subtraction.

[0036] For the observations of each common-view satellite, using known precise models and algorithms, the common error components that can be accurately calculated or modeled are subtracted to obtain the residual error components. The observation equations for carrier and pseudorange are as follows: (1) In the formula, express Time Satellite Relative to the base station No. Carrier observations at each frequency point; Indicates pseudorange observations; This indicates the actual distance from the base station receiver to the satellite; express Time Satellite Location, Indicates the location of the base station receiver; Indicates tropospheric delay error; Indicates satellite No. Ionospheric delay error at each frequency point; Indicates receiver clock bias; Indicates satellite clock bias; Indicates satellite No. Integer ambiguity at each frequency point. The compressible terms mainly include: Satellite position and receiver position: Calculate the satellite position using the known precise coordinates of the reference station and the broadcast ephemeris, and calculate the geometric distance between the reference station and the satellite; Tropospheric delay error: The tropospheric delay dry component was calculated using the Saastamoinen model; Ionospheric delay error: Ionospheric delay is calculated using ionospheric models such as Klobuchar; Satellite clock bias: The satellite clock bias is calculated using satellite clock bias parameters provided by the broadcast ephemeris. Receiver clock bias: The receiver clock bias is calculated by taking the mean of the residuals from the pseudorange observation equations of multiple satellites. (2) In the formula, Indicates the number of satellites.

[0037] Integer ambiguity: For carrier phase observations, separate and subtract the integer part of their integer ambiguity, and retain the fractional part.

[0038] (3) By eliminating the above common error components, it is ultimately possible to achieve short message broadcasting of RTK enhancement information with pseudorange correction values ​​of approximately ±2m and carrier frequency of approximately ±0.01 cycles.

[0039] Step S3: Generation and binary encoding of observation corrections.

[0040] The residual pseudorange correction value and carrier phase correction value information processed in step S2 are encoded. A compact binary encoding format needs to be designed to adapt to the capacity limitations of BeiDou short messages. The specific encoding format and the size, range, and resolution of each field can be found in Table 1. It is important to note that, to improve channel utilization efficiency, a coordinate update identifier (1 bit) is set for dynamic control of the base station coordinate information. When the identifier is "0", it indicates that the base station coordinates have not changed, and the message does not contain the base station coordinate field; when the identifier is "1", it indicates that the base station coordinates need to be updated, and the message contains the complete base station coordinate field. Simultaneously, a gross error judgment is performed when encoding and broadcasting satellites and their correction values. If the pseudorange correction value exceeds ±20.48m (where 20.48 corresponds to the upper limit of 20 bits), it is generally considered that the pseudorange residual exceeds 20m, and is therefore considered a gross error, and the satellite is skipped and not broadcast. This not only reduces bandwidth usage but also improves the reliability of the base station.

[0041] Table 1 Binary Encoding Field Information

[0042] Step S4: Short message packet assembly and broadcasting.

[0043] Based on the compact encoding format defined in step S3, the generated binary data stream is strictly packaged at the application layer according to the BeiDou short message communication protocol and broadcast to the service area through the channels of BeiDou GEO / IGSO satellites. According to calculations, using this encoding method, broadcasting the base station coordinates requires 93 bits (31 bits for a single base station coordinate multiplied by 3 directions), and broadcasting the dual-frequency observation correction values ​​of each satellite requires 39 bits (5 bits for satellite PRN + phase correction values ​​of two frequencies (7 bits * 2) + pseudorange correction values ​​of two frequencies (10 bits * 2)). If the base station coordinates are broadcast, a single epoch contains complete augmentation information from dual-frequency observations of approximately 14 satellites. After encoding, the data volume can be efficiently compressed to within 650 bits. If the base station coordinates are not broadcast, a single epoch contains complete augmentation information from dual-frequency observations of approximately 16 satellites. After encoding, the data volume can be efficiently compressed to within 635 bits (base station broadcast identifier 1 + observation time 6 + number of satellites 4 + 16 satellites and their dual-frequency corrections (16*39)), which is lower than the maximum capacity limit of a single BeiDou short message (650 bits), fully meeting the transmission requirements for real-time and reliable broadcasting.

[0044] Step S5: Rover receives, decodes, and calculates positioning data.

[0045] The user station receives BeiDou short message information and parses it to obtain the reference station coordinates, observation time, pseudorange of each satellite, and carrier phase correction. Using its own GNSS observations and the corrected information obtained from the parsing, the user station eliminates residual common errors and quickly fixes integer ambiguities under a unified spatiotemporal reference, employing methods such as the double-difference model, ultimately calculating the user station's high-precision coordinates.

[0046] In summary, the present invention solves the following problems: (1) Common error modeling and residual coding technology: By accurately modeling and subtracting common errors (such as satellite position, clock error, troposphere, ionosphere, etc.) in GNSS observations, only the residual pseudorange and carrier phase correction values ​​are efficiently binary encoded to achieve a large compression of data volume and meet the bandwidth limit of Beidou short message.

[0047] (2) Dynamic reference station coordinate broadcasting mechanism: Set a coordinate update identifier (1 bit) and broadcast the complete coordinate information only when the reference station coordinates change, which greatly improves the channel utilization efficiency.

[0048] (3) Gross error detection and satellite screening mechanism: Before encoding and broadcasting, gross error judgment is performed on pseudorange correction values ​​(if the error exceeds ±20.48m, the satellite is skipped) to reduce invalid data transmission and enhance system reliability.

[0049] (4) RTK enhancement information broadcasting method applicable to satellite-based links: Using the BeiDou short message communication protocol, the compressed correction data is broadcast through GEO / IGSO satellites to achieve real-time high-precision positioning without ground networks in the global or regional area.

[0050] (5) Efficient coding structure of dual-frequency observations: The compact binary field (such as 7 bits for phase correction and 10 bits for pseudorange correction) is designed to support the complete broadcast of dual-frequency correction information of 14-16 satellites in a single epoch within 650 bits, meeting the requirements for real-time broadcast.

[0051] The following describes the satellite-based RTK positioning enhancement system based on short message communication provided by the present invention. The satellite-based RTK positioning enhancement system based on short message communication described below can be referred to in correspondence with the satellite-based RTK positioning enhancement method based on short message communication described above.

[0052] Figure 3 This is a schematic diagram of the structure of a satellite-based RTK positioning enhancement system based on short message communication provided in an embodiment of the present invention, as shown below. Figure 3 As shown, it includes: a data acquisition module 31, a calculation module 32, an encoding module 33, a transmission module 34, and a solution module 35, wherein: The acquisition module 31 is used to acquire data from the reference station to obtain a set of positioning observations; the calculation module 32 is used to perform common error calculation and modeling on the set of positioning observations to obtain the observation correction values; the encoding module 33 is used to construct a base station update query list, encode the observation correction values, and generate a binary data stream; the sending module 34 is used to assemble and broadcast the binary data stream into short messages based on the encoding format, and send it to the target user station; the solution module 35 is used by the target user station to receive the binary data stream and solve for the target user station's position coordinates.

[0053] Figure 4 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 4 As shown, the electronic device may include a processor 410, a communications interface 420, a memory 430, and a communication bus 440. The processor 410, communications interface 420, and memory 430 communicate with each other via the communication bus 440. The processor 410 can call logical instructions in the memory 430 to execute a satellite-based RTK positioning enhancement method based on short message communication. This method includes: a reference station acquiring data to obtain a set of positioning observations; performing common error calculation and modeling on the set of positioning observations to obtain observation correction values; constructing a reference station update query list, encoding the observation correction values, and generating a binary data stream; based on the encoding format, packetizing and broadcasting the binary data stream into short messages and sending it to a target user station; and the target user station receiving the binary data stream and calculating its position coordinates.

[0054] Furthermore, the logical instructions in the aforementioned memory 430 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0055] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the satellite-based RTK positioning enhancement method based on short message communication provided by the above methods. The method includes: a reference station collecting data to obtain a set of positioning observations; performing common error calculation and modeling on the set of positioning observations to obtain observation correction values; constructing a reference station update query list, encoding the observation correction values, and generating a binary data stream; based on the encoding format, packetizing and broadcasting the binary data stream into short messages and sending it to a target user station; and the target user station receiving the binary data stream and calculating the target user station's position coordinates.

[0056] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the satellite-based RTK positioning enhancement method based on short message communication provided by the methods described above. The method includes: a reference station collecting data to obtain a set of positioning observations; performing common error calculation and modeling on the set of positioning observations to obtain observation correction values; constructing a base station update query list, encoding the observation correction values, and generating a binary data stream; based on the encoding format, packetizing and broadcasting the binary data stream into short messages and sending it to a target user station; and the target user station receiving the binary data stream and calculating the target user station's position coordinates.

[0057] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0058] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for positioning enhancement of satellite-based RTK based on short message communication, characterized in that, The method comprises the following steps: The reference station collects data to obtain a set of positioning observation values; Common error calculation and modeling processing are performed on the set of positioning observation values to obtain observation value correction values; A reference station update query list is constructed, and the observation value correction values are encoded to generate a binary data stream; Based on the encoding format, the binary data stream is packaged and broadcasted in short messages to send to the target user station; The target user station receives the binary data stream and solves to obtain the position coordinates of the target user station.

2. The short message communication-based satellite-based RTK positioning enhancement method according to claim 1, characterized in that, The reference station collects data to obtain a set of positioning observation values, which comprises the following steps: The reference station receives original pseudo-range and carrier phase observation values of multi-frequency and multi-mode GNSS satellites; Satellite broadcast ephemeris and satellite broadcast clock difference are obtained. 3.The short message communication based positioning enhancement method of SB-RTK according to claim 1, wherein, Common error calculation and modeling processing are performed on the set of positioning observation values to obtain observation value correction values, which comprises the following steps: Carrier observation equation and pseudo-range observation equation are obtained; The geometric distance between the reference station and the satellite is calculated by using the satellite position obtained by the reference station coordinate position and the satellite broadcast ephemeris; The tropospheric delay error is calculated by using the Saastamoinen model; The ionospheric delay error is calculated by using the Klobuchar ionospheric model; The satellite clock difference is calculated by using the satellite clock difference parameter provided by the satellite broadcast ephemeris; The receiver clock difference is calculated by calculating the residual mean of the pseudo-range observation equation of multiple satellites; The integer part of the integer ambiguity in the carrier phase observation value is removed, and the decimal part is retained to obtain the processed integer ambiguity; The residual pseudo-range correction value and the carrier phase correction value are obtained by comprehensively considering the geometric distance between the reference station and the satellite, the tropospheric delay error, the ionospheric delay error, the satellite clock difference, the receiver clock difference, and the processed integer ambiguity.

4. The short message communication-based positioning enhancement method of the satellite-based RTK according to claim 1, wherein, A reference station update query list is constructed, and the observation value correction values are encoded to generate a binary data stream, which comprises the following steps: The elements of the reference station update query list include the base station broadcast identifier, the base station coordinates, the observation time, the number of satellites, the satellite PRN number, the phase correction value, and the pseudo-range correction value. All elements include corresponding size values, value ranges, resolutions, and broadcast mechanisms; The base station broadcast identifier includes a coordinate update identifier and a coordinate update identifier; According to the reference station update query list, the residual pseudo-range correction value and the carrier phase correction value are encoded to output the binary data stream.

5. The short message communication-based augmentation method for positioning with star-based RTK according to claim 1, characterized in that, Based on the encoding format, the binary data stream is packaged and broadcasted in short messages to send to the target user station, which comprises the following steps: According to the preset satellite short message communication protocol, the binary data stream is applied to the application layer packaging; The data packet is broadcasted to the target user station in the service area through the channel of the preset satellite.

6. The short message communication-based positioning enhancement method of the satellite-based RTK according to claim 1, wherein, The target user station receives the binary data stream and solves to obtain the position coordinates of the target user station, which comprises the following steps: The target user station analyzes the binary data stream to obtain the reference station coordinate position, the observation time, and the residual pseudo-range correction value and the carrier phase correction value of each satellite; The target user station uses its own GNSS observations, combined with the residual pseudorange correction and carrier phase correction obtained by analysis, and uses a unified spatiotemporal reference to eliminate residual common errors, fix integer ambiguities, and calculate the position coordinates of the target user station.

7. A short message communication-based satellite-based RTK positioning enhancement system, characterized in that, include: The data acquisition module is used by the reference station to collect data and obtain a set of positioning observation values; The calculation module is used to perform common error calculation and modeling on the set of positioning observations to obtain the observation correction values; The encoding module is used to construct the base station update query list, encode the observed value correction values, and generate a binary data stream. The sending module is used to assemble and broadcast the binary data stream into short messages based on the encoding format and send it to the target user station; The calculation module is used to receive the binary data stream from the target user station and calculate the location coordinates of the target user station.

8. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the satellite-based RTK positioning enhancement method based on short message communication as described in any one of claims 1 to 6. 9.A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that, When the computer program is executed by the processor, it implements the satellite-based RTK positioning enhancement method based on short message communication as described in any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the satellite-based RTK positioning enhancement method based on short message communication as described in any one of claims 1 to 6.

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