RTK differential data transmission method based on polarization code and LoRa modulation

Abstract

The invention discloses an RTK differential data transmission method based on a polarization code and LoRa modulation, and belongs to the technical field of surveying and mapping, and the method comprises the steps: obtaining the observation data of a reference station, and dividing the observation data of the reference station into a plurality of bit sequences; performing reliability evaluation on each bit sequence, performing polarization code coding and LoRa modulation on each bit sequence according to an evaluation result, and generating a plurality of reference station LoRa symbols; and transmitting the reference station LoRa symbol to a mobile station, so that the mobile station carries out chirp removal and polarization code decoding on the reference station LoRa symbol to obtain a reference station observation data estimation value, and in combination with pre-obtained mobile station observation data, a mobile station data value is obtained. According to the method disclosed by the invention, the transmission reliability of the RTK radio station in a remote area can be improved.

Description

Technical Field

[0001] This invention belongs to the field of surveying and mapping technology, specifically relating to an RTK differential data transmission method based on polar codes and LoRa modulation. Background Technology

[0002] The rapid development of global navigation satellite system technology has brought revolutionary changes to the field of high-precision positioning. Among them, real-time dynamic differential positioning (RTK) technology has become a key technology for achieving centimeter-level real-time positioning. Its core technology lies in the collaborative work of the RTK reference station and the RTK rover station to achieve data transmission. The widespread application of this technology in fields such as field surveying, precision agriculture, and geological disaster monitoring is driving technological upgrades in related industries.

[0003] However, in remote areas such as mountainous regions and deserts, this technology suffers from insufficient communication network coverage and a lack of adaptation and optimization of transmission characteristics between the RTK reference station and the RTK mobile station, making it impossible to establish an effective data link and resulting in unstable data transmission in the RTK system. Due to the unique geographical constraints, it is often difficult to deploy a stable communication network in these areas by increasing the number of RTK reference stations, making it impossible for RTK technology to provide stable and reliable data transmission in these remote regions. Even under weak signal conditions, the communication process implemented by existing technologies will experience a significant increase in the bit error rate due to signal fading and Doppler shift, and the performance of the RTK system may deteriorate rapidly with increasing distance and terminal movement, thus affecting the reliability of data transmission. Therefore, the transmission reliability of existing technologies in remote areas is poor. Summary of the Invention

[0004] The present invention aims to provide an RTK differential data transmission method based on polar codes and LoRa (Long Range Radio) modulation to solve the above-mentioned technical problems and improve the transmission reliability of RTK radios in remote areas.

[0005] To address the aforementioned technical problems, this invention provides an RTK differential data transmission method based on polar codes and LoRa modulation, implemented using an RTK radio, which includes a reference station and a rover station. The method comprises the following steps: Acquire reference station observation data and divide the reference station observation data into several bit sequences; For each bit sequence, a reliability assessment is performed. Based on the assessment results, each bit sequence is polar-coded and LoRa modulated to generate several reference station LoRa symbols. The reference station LoRa symbol is transmitted to the mobile station, which then performs dechirping and polar code decoding on the reference station LoRa symbol to obtain the estimated value of the reference station observation data. Combined with the pre-acquired mobile station observation data, the mobile station data value is obtained to complete the data transmission.

[0006] It should be noted that the acquired reference station observation data or rover station observation data refers to the positioning data transmitted by the satellite and received by the GNSS receiver of the reference station or rover station.

[0007] In the above scheme, after acquiring the reference station observation data, it is divided into several bit sequences. Each bit sequence undergoes a reliability assessment. Based on the assessment results, each bit sequence is encoded using polar codes and modulated using LoRa to generate several reference station LoRa symbols. Channel polarization is achieved through reliability assessment, and LoRa modulation is used to generate LoRa symbols suitable for long-distance transmission, thereby improving transmission reliability. After transmitting the LoRa symbols to the mobile station, the mobile station performs dechirping and polar code decoding on the reference station LoRa symbols to obtain an estimated value of the reference station observation data. This value is then combined with pre-acquired mobile station observation data to obtain the mobile station data value. This effectively offsets errors during long-distance data transmission, maximizing the preservation of reference station observation data, thereby improving the transmission reliability of RTK radios in remote areas.

[0008] Furthermore, the reliability assessment of each bit sequence, and the polar code encoding and LoRa modulation of each bit sequence based on the assessment results to generate several reference station LoRa symbols, includes: assessing the reliability of the polar sub-channels of each bit sequence; sorting the polar sub-channels of each bit sequence based on the assessment results to obtain several source bit sequences; calculating each source bit sequence to obtain several polar codewords; interleaving each polar codeword to obtain several interleaved sequences; and performing LoRa modulation on each interleaved sequence to generate several LoRa symbols.

[0009] It should be noted that the reliability assessment of the polarization sub-channel for each bit sequence is a process of reliability estimation for the polarization sub-channel carrying the bit sequence. Specifically, it involves determining the reliability of the polarization sub-channel based on the length of the bit sequence. Thus, the code length of the polar code is determined. and information bit length The bitrate is Assume there are a total of For each bit sequence, firstly, the reliability of each polar sub-channel of the polar code is estimated, then the channels are sorted according to their reliability, and the most reliable one is selected. One sub-channel is used to transmit the information bits in the bit sequence. These information bits are the bits that contain the required data, while the remaining... Each sub-channel is used to transmit frozen bits from the bit sequence. These frozen bits are error-correcting redundancy bits, and their values ​​are preset fixed values, thus obtaining the source bit sequence. Then, by calculating its nth-order Kronecker product, the generator matrix, identity matrix, and permutation matrix are obtained, where... These matrices are then multiplied by the source bit sequence to obtain several polar codewords, thus completing the polar code encoding process.

[0010] In the above scheme, a reliability assessment is conducted on the polar sub-channels of each bit sequence. Based on the assessment results, the polar sub-channels of each bit sequence are sorted, and suitable channel resources for data transmission are selected to construct the source bit sequence. This process accurately matches the transmission carrier of the bit sequence with the characteristics of the polar code channel, making the polar code encoding process closer to the channel limit, thereby improving data transmission reliability. Polar code codewords are generated by processing each source bit sequence. Polar code encoding reduces the impact of data transmission errors on subsequent data processing, providing key support for ultimately improving transmission reliability. Each polar codeword is then interleaved to obtain an interleaved sequence, and LoRa modulation is applied to each interleaved sequence to generate LoRa symbols. This effectively improves the ability to transmit data over long distances, avoids partial data failure due to insufficient communication coverage in remote areas, and improves the reliability of reference station observation data during transmission in remote areas.

[0011] Furthermore, the step of performing LoRa modulation on each interleaved sequence to generate several LoRa symbols includes: determining the spreading factor of LoRa modulation based on the interleaved sequence; mapping each interleaved sequence into several bit symbols based on the spreading factor; and calculating each bit symbol to obtain a LoRa symbol.

[0012] It should be noted that this scheme determines the spreading factor used for LoRa modulation after obtaining the interleaved sequence. , It is an integer multiple of the bit length of the interleaved sequence, so that each LoRa symbol has Therefore, the interleaved sequence can be mapped to bits. Each bit symbol. Therefore, the specific process is as follows: determine the spreading factor. Then, the interleaved sequences are divided into equal parts. A length of The sequence, the first indivual The first in the interleaved sequence indivual Length is The bit symbol is then converted to decimal to generate the LoRa symbol. The generation formula is as follows: in, Represents the original rising chirp signal in discrete time; This represents the energy carried by each symbol; m represents the first... The first interleaved sequence in the nth interleaved sequence A length of The decimal bit symbol, where n represents the time domain index. .

[0013] In the above scheme, the spreading factor of LoRa modulation is determined based on the interleaved sequence, ensuring that the spreading factor matches the bit length of the interleaved sequence, thus enabling better transmission of the required data via LoRa modulation. Based on this spreading factor, each interleaved sequence is mapped into several bit symbols, transforming the coded and interleaved data into basic data units recognizable by LoRa modulation, ensuring the standardization of the modulation process. Furthermore, LoRa symbols are generated by calculating each bit symbol, enhancing the spreading characteristics of LoRa modulation, making long-distance data transmission more reliable, reducing signal attenuation and bit error rates in remote areas with weak signals and strong interference, and further improving the transmission reliability of reference station observation data.

[0014] Further, the step of transmitting the reference station LoRa symbol to the mobile station, so that the mobile station can perform dechirping and polar code decoding on the reference station LoRa symbol to obtain an estimated value of the reference station observation data, and combining it with pre-acquired mobile station observation data to obtain the mobile station data value, includes: sending the reference station LoRa symbol so that the mobile station can receive the reference station LoRa symbol; having the mobile station perform dechirping based on the reference station LoRa symbol to obtain a plurality of dechirped signals; having the mobile station calculate a plurality of LLR sequences for each dechirped signal, concatenating all LLR sequences and performing polar code decoding to obtain an estimated value of the reference station observation data; and having the mobile station obtain the mobile station data value based on the estimated value of the reference station observation data and the pre-acquired mobile station observation data.

[0015] It should be noted that the received signal of the reference station LoRa symbol can be represented as: in It is the amplitude of the fading channel coefficient. With a mean of zero and a variance of , Additive white Gaussian noise, The LoRa symbols generated above are used for dechirping. The dechirping process involves calculating the complex conjugate of the LoRa symbol, multiplying it by the received reference station LoRa symbol, and performing a Discrete Fourier Transform. Based on the output value of the Discrete Fourier Transform, the LLR (Log-Likelihood Ratio) of the reference station LoRa symbol is calculated. After calculating the LLR of all reference station LoRa symbols, all LLRs are concatenated in order, and then decoded through a successive elimination SC decoder of polar codes to obtain the estimated value of the reference station observation data.

[0016] In the above scheme, a reference station LoRa symbol is sent and received by the mobile station. Data interaction between the reference station and the mobile station is achieved through LoRa's infinite long-distance transmission, making it suitable for scenarios in remote areas without communication network coverage. The mobile station performs dechirping based on the reference station LoRa symbol to obtain a dechirped signal, eliminating FM interference during transmission and restoring the initial signal, thereby improving transmission reliability. The mobile station calculates several LLR sequences for each dechirped signal. After concatenating all LLR sequences and performing polar code decoding, the core information of the reference station's observation data can be accurately recovered, yielding an estimated value of the reference station's observation data. The mobile station then uses this estimated value combined with pre-acquired mobile station observation data to obtain the mobile station's data value, achieving accurate data transmission to the mobile station. This effectively offsets transmission errors caused by long-distance transmission in remote areas, maximizing the reliability of RTK radio data transmission.

[0017] Furthermore, the step of having the rover station obtain rover station data values ​​based on the reference station observation data estimate and combined with pre-acquired rover station observation data includes: acquiring rover station observation data; and calculating the rover station data values ​​based on the reference station observation data estimate, the rover station observation data, and a preset difference algorithm.

[0018] It should be noted that the preset differential algorithm can be a carrier phase differential positioning algorithm. By establishing a corresponding differential model between the estimated values ​​of the rover station observation data and the reference station observation data, data transmission errors are eliminated, thereby obtaining the rover station data value.

[0019] In the above scheme, acquiring rover station observation data provides the core data for solving rover station data. In the process of calculating rover station data values ​​based on the estimated values ​​of reference station observation data, rover station observation data, and preset differential algorithm, by establishing corresponding differential models for the two types of data, it is possible to effectively eliminate data deviations caused by satellite clock bias, data delay, etc. This not only makes up for data transmission distortion in weak signal scenarios in remote areas, but also realizes data calculation through differential algorithm, significantly improving the transmission reliability of rover stations in remote areas.

[0020] The present invention also provides an RTK differential data transmission system based on polar codes and LoRa modulation, comprising: a data acquisition module for acquiring reference station observation data; a data partitioning module for partitioning the reference station observation data into several bit sequences; a reliability assessment module for performing reliability assessment on each bit sequence; an encoding and modulation module for performing polar code encoding and LoRa modulation on each bit sequence according to the assessment results to generate several reference station LoRa symbols; a data transmission module for transmitting the reference station LoRa symbols to a mobile station; and a data processing module for instructing the mobile station to perform dechirping and polar code decoding on the reference station LoRa symbols to obtain an estimated value of the reference station observation data, and combining it with pre-acquired mobile station observation data to obtain the mobile station data value.

[0021] Furthermore, the reliability assessment module is used to perform reliability assessment on each bit sequence, including: assessing the reliability of the polarization sub-channels of each bit sequence, and sorting the polarization sub-channels of each bit sequence according to the assessment results to obtain several source bit sequences.

[0022] Furthermore, the coding and modulation module is used to perform polar code encoding and LoRa modulation on each bit sequence according to the evaluation results to generate several reference station LoRa symbols, including: calculating each source bit sequence to obtain several polar code words; interleaving each polar code word to obtain several interleaved sequences; and performing LoRa modulation on each interleaved sequence to generate several LoRa symbols.

[0023] Furthermore, the data processing module is used to instruct the mobile station to perform dechirping and polar code decoding on the reference station LoRa symbol to obtain an estimated value of the reference station observation data, and to obtain the mobile station data value by combining it with the pre-acquired mobile station observation data. This includes: instructing the mobile station to perform dechirping based on the reference station LoRa symbol to obtain several dechirped signals; instructing the mobile station to calculate several LLR sequences for each dechirped signal, concatenating all LLR sequences and performing polar code decoding to obtain an estimated value of the reference station observation data; and instructing the mobile station to obtain the mobile station data value based on the estimated value of the reference station observation data and the pre-acquired mobile station observation data.

[0024] Furthermore, it also includes a rover observation data acquisition module for acquiring rover observation data.

[0025] The system architecture provided by the above solution has clear logic, distinct functional divisions for each module, and close coordination, forming a complete closed-loop link for data encoding, transmission, and resolution: The data acquisition module first obtains the reference station observation data. After the data division module splits it into a standardized bit sequence, it is passed to the reliability evaluation module to complete reliability evaluation and sorting, generating a source bit sequence adapted for encoding. After receiving the source bit sequence, the encoding and modulation module completes polar code encoding and LoRa modulation, and outputs a reference station LoRa symbol adapted for long-distance transmission. After the data transmission module wirelessly transmits this LoRa symbol to the mobile station, the data processing module drives the mobile station to complete de-chirping, LLR sequence calculation, and polar code decoding, restoring the estimated value of the reference station observation data. At the same time, the mobile station observation data acquisition module synchronously captures the mobile station observation data, and finally combines the two types of data to obtain the mobile station data value. The core of this system lies in the collaborative work of the encoding and modulation module and the data processing module. The encoding and modulation module generates a LoRa symbol adapted for long-distance transmission in remote areas through polar code encoding and LoRa modulation, improving transmission reliability. The data processing module drives the mobile station to complete de-chirping of the LoRa symbol and polar code decoding, accurately restoring the reference station observation data, and then combines the mobile station observation data to complete differential resolution, forming a closed-loop collaborative link for anti-interference encoding modulation and accurate data transmission. This collaborative mechanism specifically solves the problem of unreliable transmission caused by insufficient coverage of the communication network and signal fading in remote areas. The system is adapted to remote scenarios without network coverage such as mountains and deserts, and does not rely on traditional communication networks to build data links. It only realizes reliable data transmission through the linkage of core functional modules, achieving the core goal of improving the transmission reliability of RTK radios in remote areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic flowchart of a method for RTK differential data transmission based on polar codes and LoRa modulation provided by an embodiment of the present invention; Figure 2 is a schematic diagram of the system architecture of an RTK differential data transmission based on polar codes and LoRa modulation provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Please refer to Figure 1 , this embodiment provides a method, including the following steps: Step S1: Obtain the reference station observation data and divide the reference station observation data into several bit sequences; Step S2: Perform reliability assessment on each bit sequence, and based on the assessment results, perform polar code encoding and LoRa modulation on each bit sequence to generate several reference station LoRa symbols; Step S3: Transmit the reference station LoRa symbol to the mobile station so that the mobile station can perform dechirping and polar code decoding on the reference station LoRa symbol to obtain the estimated value of the reference station observation data, and combine it with the pre-acquired mobile station observation data to obtain the mobile station data value.

[0029] It should be noted that the acquired reference station observation data or rover station observation data refers to the positioning data transmitted by the satellite and received by the GNSS receiver of the reference station or rover station.

[0030] In this embodiment, after acquiring the reference station observation data, it is divided into several bit sequences. Each bit sequence undergoes a reliability assessment. Based on the assessment results, each bit sequence is encoded using polar codes and modulated using LoRa to generate several reference station LoRa symbols. Channel polarization is achieved through reliability assessment, and LoRa modulation is used to generate LoRa symbols suitable for long-distance transmission, thereby improving transmission reliability. After transmitting the LoRa symbols to the mobile station, the mobile station performs dechirping and polar code decoding on the reference station LoRa symbols to obtain an estimated value of the reference station observation data. This value is then combined with pre-acquired mobile station observation data to obtain the mobile station data value. This effectively offsets errors during long-distance data transmission, maximizing the preservation of reference station observation data and thus improving the transmission reliability of the RTK radio in remote areas.

[0031] Furthermore, the reliability assessment of each bit sequence, and the polar code encoding and LoRa modulation of each bit sequence based on the assessment results to generate several reference station LoRa symbols, includes: assessing the reliability of the polar sub-channels of each bit sequence; sorting the polar sub-channels of each bit sequence based on the assessment results to obtain several source bit sequences; calculating each source bit sequence to obtain several polar codewords; interleaving each polar codeword to obtain several interleaved sequences; and performing LoRa modulation on each interleaved sequence to generate several LoRa symbols.

[0032] It should be noted that the reliability assessment of the polarization sub-channel for each bit sequence is a process of reliability estimation for the polarization sub-channel carrying the bit sequence. Specifically, it involves determining the reliability of the polarization sub-channel based on the length of the bit sequence. Thus, the code length of the polar code is determined. and information bit length The bitrate is Assume there are a total of For each bit sequence, firstly, the reliability of each polar sub-channel of the polar code is estimated, then the channels are sorted according to their reliability, and the most reliable one is selected. One sub-channel is used to transmit the information bits in the bit sequence. These information bits are the bits that contain the required data, while the remaining... Each sub-channel is used to transmit frozen bits from the bit sequence. These frozen bits are error-correcting redundancy bits, and their values ​​are preset fixed values, thus obtaining the source bit sequence. Then, by calculating its nth-order Kronecker product, the generator matrix, identity matrix, and permutation matrix are obtained, where... These matrices are then multiplied by the source bit sequence to obtain several polar codewords, thus completing the polar code encoding process.

[0033] In this embodiment, a reliability assessment is performed on the polar sub-channels of each bit sequence. Based on the assessment results, the polar sub-channels of each bit sequence are sorted, and suitable channel resources for data transmission are selected to construct the source bit sequence. This process precisely matches the transmission carrier of the bit sequence with the characteristics of the polar code channel, making the polar code encoding process closer to the channel limit, thereby improving data transmission reliability. Polar code codewords are generated by processing each source bit sequence. Polar code encoding reduces the impact of data transmission errors on subsequent data processing, providing crucial support for ultimately improving transmission reliability. Each polar codeword is then interleaved to obtain an interleaved sequence, and LoRa modulation is applied to each interleaved sequence to generate LoRa symbols. This effectively improves the ability to transmit data over long distances, avoids partial data failure due to insufficient communication coverage in remote areas, and improves the reliability of reference station observation data during transmission in remote areas.

[0034] Furthermore, the step of performing LoRa modulation on each interleaved sequence to generate several LoRa symbols includes: determining the spreading factor of LoRa modulation based on the interleaved sequence; mapping each interleaved sequence into several bit symbols based on the spreading factor; and calculating each bit symbol to obtain a LoRa symbol.

[0035] It should be noted that, in this embodiment, after obtaining the interleaved sequence, the spreading factor used for LoRa modulation is determined. , It is an integer multiple of the bit length of the interleaved sequence, so that each LoRa symbol has Therefore, the interleaved sequence can be mapped to bits. Each bit symbol. Therefore, the specific process is as follows: determine the spreading factor. Then, the interleaved sequences are divided into equal parts. A length of The sequence, the first indivual The first in the interleaved sequence indivual Length is The bit symbol is then converted to decimal to generate the LoRa symbol. The generation formula is as follows: in, Represents the original rising chirp signal in discrete time; This represents the energy carried by each symbol; m represents the first... The first interleaved sequence in the nth interleaved sequence A length of The decimal bit symbol, where n represents the time domain index. .

[0036] In this embodiment, the spreading factor of LoRa modulation is determined based on the interleaving sequence, ensuring that the spreading factor matches the bit length of the interleaving sequence. This allows for better transmission of the required data via LoRa modulation. Based on this spreading factor, each interleaving sequence is mapped into several bit symbols, transforming the coded and interleaved data into basic data units recognizable by LoRa modulation, ensuring the standardization of the modulation process. Furthermore, LoRa symbols are generated by calculating each bit symbol, enhancing the spreading characteristics of LoRa modulation. This makes long-distance data transmission more reliable, reducing signal attenuation and bit error rates in remote areas with weak signals and strong interference, further improving the transmission reliability of reference station observation data.

[0037] Further, the step of transmitting the reference station LoRa symbol to the mobile station, so that the mobile station can perform dechirping and polar code decoding on the reference station LoRa symbol to obtain an estimated value of the reference station observation data, and combining it with pre-acquired mobile station observation data to obtain the mobile station data value, includes: sending the reference station LoRa symbol so that the mobile station can receive the reference station LoRa symbol; having the mobile station perform dechirping based on the reference station LoRa symbol to obtain a plurality of dechirped signals; having the mobile station calculate a plurality of LLR sequences for each dechirped signal, concatenating all LLR sequences and performing polar code decoding to obtain an estimated value of the reference station observation data; and having the mobile station obtain the mobile station data value based on the estimated value of the reference station observation data and the pre-acquired mobile station observation data.

[0038] It should be noted that the received signal of the reference station LoRa symbol can be represented as: in It is the amplitude of the fading channel coefficient. With a mean of zero and a variance of , Additive white Gaussian noise, The LoRa symbols generated above are used for dechirping. The dechirping process involves calculating the complex conjugate of the LoRa symbol, multiplying it by the received reference station LoRa symbol, and performing a Discrete Fourier Transform. Based on the output value of the Discrete Fourier Transform, the LLR (Log-Likelihood Ratio) of the reference station LoRa symbol is calculated. After calculating the LLR of all reference station LoRa symbols, all LLRs are concatenated in order, and then decoded through a successive elimination SC decoder of polar codes to obtain the estimated value of the reference station observation data.

[0039] In this embodiment, a reference station LoRa symbol is sent and received by the mobile station. Data interaction between the reference station and the mobile station is achieved through LoRa's infinite long-distance transmission, adaptable to scenarios in remote areas without communication network coverage. The mobile station performs dechirping based on the reference station LoRa symbol to obtain a dechirped signal, eliminating frequency modulation interference during transmission and restoring the initial signal, thereby improving transmission reliability. The mobile station calculates several LLR sequences for each dechirped signal. After concatenating all LLR sequences and performing polar code decoding, the core information of the reference station's observation data can be accurately recovered, yielding an estimated value of the reference station's observation data. The mobile station then uses this estimated value combined with pre-acquired mobile station observation data to obtain the mobile station's data value, achieving accurate data transmission to the mobile station. This effectively offsets transmission errors caused by long-distance transmission in remote areas, maximizing the reliability of RTK radio data transmission.

[0040] Furthermore, the step of having the rover station obtain rover station data values ​​based on the reference station observation data estimate and combined with pre-acquired rover station observation data includes: acquiring rover station observation data; and calculating the rover station data values ​​based on the reference station observation data estimate, the rover station observation data, and a preset difference algorithm.

[0041] It should be noted that the preset differential algorithm can be a carrier phase differential positioning algorithm. By establishing a corresponding differential model between the estimated values ​​of the rover station observation data and the reference station observation data, data transmission errors are eliminated, thereby obtaining the rover station data value.

[0042] In this embodiment, acquiring rover station observation data provides core data for the calculation of rover station data. In the process of calculating rover station data values ​​based on the estimated values ​​of reference station observation data, rover station observation data, and preset differential algorithm, by establishing corresponding differential models for the two types of data, data deviations caused by satellite clock bias, data delay, etc. can be effectively eliminated. This not only compensates for data transmission distortion in weak signal scenarios in remote areas, but also realizes data calculation through differential algorithm, significantly improving the transmission reliability of rover stations in remote areas.

[0043] Please see Figure 2This embodiment also provides an RTK differential data transmission system based on polar codes and LoRa modulation, comprising: a data acquisition module for acquiring reference station observation data; a data partitioning module for partitioning the reference station observation data into several bit sequences; a reliability assessment module for performing reliability assessment on each bit sequence; an encoding and modulation module for performing polar code encoding and LoRa modulation on each bit sequence according to the assessment results to generate several reference station LoRa symbols; a data transmission module for transmitting the reference station LoRa symbols to a mobile station; and a data processing module for instructing the mobile station to perform dechirping and polar code decoding on the reference station LoRa symbols to obtain an estimated value of the reference station observation data, and combining it with pre-acquired mobile station observation data to obtain the mobile station data value.

[0044] Furthermore, the reliability assessment module is used to perform reliability assessment on each bit sequence, including: assessing the reliability of the polarization sub-channels of each bit sequence, and sorting the polarization sub-channels of each bit sequence according to the assessment results to obtain several source bit sequences.

[0045] Furthermore, the coding and modulation module is used to perform polar code encoding and LoRa modulation on each bit sequence according to the evaluation results to generate several reference station LoRa symbols, including: calculating each source bit sequence to obtain several polar code words; interleaving each polar code word to obtain several interleaved sequences; and performing LoRa modulation on each interleaved sequence to generate several LoRa symbols.

[0046] Furthermore, the data processing module is used to instruct the mobile station to perform dechirping and polar code decoding on the reference station LoRa symbol to obtain an estimated value of the reference station observation data, and to obtain the mobile station data value by combining it with the pre-acquired mobile station observation data. This includes: instructing the mobile station to perform dechirping based on the reference station LoRa symbol to obtain several dechirped signals; instructing the mobile station to calculate several LLR sequences for each dechirped signal, concatenating all LLR sequences and performing polar code decoding to obtain an estimated value of the reference station observation data; and instructing the mobile station to obtain the mobile station data value based on the estimated value of the reference station observation data and the pre-acquired mobile station observation data.

[0047] Furthermore, it also includes a rover observation data acquisition module for acquiring rover observation data.

[0048] The system architecture provided by this embodiment has clear logic. The functions of each module are clearly divided and cooperate closely, forming a complete closed-loop link for data encoding, transmission, and decoding: The data acquisition module first acquires the reference station observation data. After the data division module splits it into standardized bit sequences, it is passed to the reliability evaluation module to complete reliability evaluation and sorting, generating a source bit sequence suitable for encoding. After receiving the source bit sequence, the encoding and modulation module completes polar code encoding and LoRa modulation, and outputs a reference station LoRa symbol suitable for long-distance transmission. After the data transmission module wirelessly transmits this LoRa symbol to the mobile station, the data processing module drives the mobile station to complete de-chirping, LLR sequence calculation, and polar code decoding, restoring the estimated value of the reference station observation data. At the same time, the mobile station observation data acquisition module synchronously captures the mobile station observation data, and finally combines the two types of data to obtain the mobile station data value. The core of this system lies in the collaborative work of the encoding and modulation module and the data processing module. The encoding and modulation module generates a LoRa symbol suitable for long-distance transmission in remote areas through polar code encoding and LoRa modulation, improving transmission reliability. The data processing module drives the mobile station to complete de-chirping of the LoRa symbol and polar code decoding, accurately restoring the reference station observation data, and then combines the mobile station observation data to complete differential decoding, forming a closed-loop collaborative link for anti-interference encoding modulation and accurate data transmission. This collaborative mechanism specifically solves the problem of unreliable transmission caused by insufficient coverage of the communication network and signal fading in remote areas. The system is suitable for remote scenarios without network coverage such as mountains and deserts. Without relying on the traditional communication network to build a data link, it only realizes reliable data transmission through the linkage of the core functional modules, achieving the core goal of improving the transmission reliability of the RTK radio station in remote areas.

[0049] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. An RTK differential data transmission method based on polar codes and LoRa modulation, characterized in that, Based on an RTK radio, which includes a reference station and a rover station, the method includes: Acquire reference station observation data and divide the reference station observation data into several bit sequences; For each bit sequence, a reliability assessment is performed. Based on the assessment results, each bit sequence is polar-coded and LoRa modulated to generate several reference station LoRa symbols. The reference station LoRa symbol is transmitted to the mobile station, which then performs dechirping and polar code decoding on the reference station LoRa symbol to obtain the estimated value of the reference station observation data. Combined with the pre-acquired mobile station observation data, the mobile station data value is obtained to complete the data transmission.

2. The RTK differential data transmission method based on polar codes and LoRa modulation according to claim 1, characterized in that, The process involves performing a reliability assessment on each bit sequence, and based on the assessment results, performing polar code encoding and LoRa modulation on each bit sequence to generate several reference station LoRa symbols, including: The reliability of the polarization sub-channels of each bit sequence is evaluated, and the polarization sub-channels of each bit sequence are sorted according to the evaluation results to obtain several source bit sequences. Calculate each of the source bit sequences to obtain several polar code codes; Each polar codeword is interleaved to obtain several interleaved sequences; Each interleaved sequence is LoRa modulated to generate several LoRa symbols.

3. The RTK differential data transmission method based on polar codes and LoRa modulation according to claim 2, characterized in that, The step of performing LoRa modulation on each interleaved sequence to generate several LoRa symbols includes: The spreading factor of LoRa modulation is determined based on the interleaved sequence; Based on the spreading factor, each interleaved sequence is mapped into several bit symbols; Calculate the symbol for each bit to obtain the LoRa symbol.

4. The RTK differential data transmission method based on polar codes and LoRa modulation according to claim 1, characterized in that, The process of transmitting the reference station LoRa symbol to the mobile station, enabling the mobile station to dechirp and decode the reference station LoRa symbol to obtain an estimated value of the reference station observation data, and combining this with pre-acquired mobile station observation data to obtain the mobile station data value, includes: The reference station LoRa symbol is sent so that the mobile station receives the reference station LoRa symbol; The mobile station performs dechirping based on the LoRa symbol of the reference station to obtain several dechirped signals; The rover station calculates several LLR sequences for each dechirped signal, concatenates all LLR sequences and performs polar code decoding to obtain the estimated value of the reference station's observation data; The rover station estimates the rover station's data value based on the reference station's observation data and combines it with the pre-acquired rover station observation data.

5. The RTK differential data transmission method based on polar codes and LoRa modulation according to claim 4, characterized in that, The process of having the rover station estimate its data value based on the reference station's observation data, combined with pre-acquired rover station observation data, to obtain the rover station data value includes: Acquire observation data from the mobile station; Based on the estimated value of the reference station observation data, the rover station observation data, and the preset difference algorithm, the rover station data value is calculated.

6. An RTK differential data transmission system based on polar codes and LoRa modulation, characterized in that, include: The data acquisition module is used to acquire observation data from the reference station; The data partitioning module is used to divide the reference station observation data into several bit sequences; The reliability assessment module is used to assess the reliability of each bit sequence. The coding and modulation module is used to encode each bit sequence with polar code and modulate it with LoRa based on the evaluation results, generating several reference station LoRa symbols; The data transmission module is used to transmit the LoRa symbol of the reference station to the mobile station; The data processing module is used to instruct the mobile station to perform dechirping and polar code decoding on the LoRa symbol of the reference station to obtain the estimated value of the reference station observation data, and to obtain the mobile station data value by combining it with the pre-acquired mobile station observation data.

7. The RTK differential data transmission system based on polar codes and LoRa modulation according to claim 6, characterized in that, The reliability assessment module is used to perform reliability assessment on each bit sequence, including: assessing the reliability of the polarization sub-channels of each bit sequence, and sorting the polarization sub-channels of each bit sequence according to the assessment results to obtain several source bit sequences.

8. The RTK differential data transmission system based on polar codes and LoRa modulation according to claim 7, characterized in that, The encoding and modulation module is used to perform polar code encoding and LoRa modulation on each bit sequence according to the evaluation results, generating several reference station LoRa symbols, including: Calculate each of the source bit sequences to obtain several polar code codes; Each polar codeword is interleaved to obtain several interleaved sequences; Each interleaved sequence is LoRa modulated to generate several LoRa symbols.

9. The RTK differential data transmission system based on polar codes and LoRa modulation according to claim 6, characterized in that, The data processing module is used to instruct the mobile station to perform dechirping and polar code decoding on the reference station's LoRa symbol to obtain an estimated value of the reference station's observation data, and to combine this with pre-acquired mobile station observation data to obtain the mobile station's data value, including: The mobile station performs dechirping based on the LoRa symbol of the reference station to obtain several dechirped signals; The rover station calculates several LLR sequences for each dechirped signal, concatenates all LLR sequences and performs polar code decoding to obtain the estimated value of the reference station's observation data; The rover station estimates the rover station's data value based on the reference station's observation data and combines it with the pre-acquired rover station observation data.

10. The RTK differential data transmission system based on polar codes and LoRa modulation according to claim 6, characterized in that, It also includes a rover station observation data acquisition module, used to acquire rover station observation data.

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