Vehicle-mounted single Beidou positioning terminal system

Abstract

The invention discloses a vehicle-mounted single Beidou positioning terminal system, and belongs to the technical field of vehicle-mounted positioning, the vehicle-mounted single Beidou positioning terminal system comprises a processor, a Beidou satellite navigation receiver and a memory which are installed on a vehicle, and the Beidou satellite navigation receiver is used for receiving signals sent by a Beidou satellite to the ground and determining Beidou satellite signals; the processor is used for processing the Beidou satellite signals and determining vehicle position information; and the memory is used for storing the Beidou satellite signal and the vehicle position information. The vehicle-mounted positioning terminal solves the problems that an existing vehicle-mounted positioning terminal is poor in positioning reliability and cannot effectively improve the safety and the operation efficiency of a vehicle. The Beidou satellite navigation receiver is used for receiving signals sent to the ground from the Beidou satellite, the Beidou satellite signals are determined, the processor is used for processing the Beidou satellite signals, the vehicle position information is determined, high precision and reliability are achieved, the safety and operation efficiency of the vehicle can be effectively improved, and the use effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle-mounted positioning, and in particular to a vehicle-mounted single Beidou positioning terminal system. Background Art

[0002] With the rapid development of the Internet of Things, the Internet of Vehicles has become an important part of the Internet of Things. It uses wireless communication and network technology, as well as advanced sensing devices, to collect, analyze and process various types of automobile information to achieve effective management and efficient use of vehicles. Among them, the on-board positioning terminal is an important device for realizing the collection of vehicle location information, mainly completing vehicle tracking and route planning.

[0003] The Chinese patent with publication number CN105510947B discloses a vehicle-mounted positioning terminal and a vehicle-mounted positioning method, wherein the vehicle-mounted positioning terminal includes: a GPS hardware module, a communication hardware module and a central control module; the central control module includes a GPS unit, a communication unit and a business logic unit; the business logic unit is used to determine whether to turn on the GPS hardware module according to the closing cycle of the GPS hardware module and the acquired motion parameters of the vehicle-mounted positioning terminal; the GPS hardware module is used to collect the positioning information of the location of the vehicle-mounted positioning terminal during the operation cycle; the business logic unit is also used to obtain the positioning information collected by the GPS hardware module and process it, and send the processed information to the communication hardware module; the communication hardware module is used to send the information processed by the business logic unit to an external communication server or mobile terminal; it can solve the problem of short standby and working time of the vehicle-mounted positioning terminal, save power consumption, and provide a longer tracking time; however, the patent has the following defects: The existing vehicle-mounted positioning terminal has poor positioning reliability and cannot effectively improve the safety and operating efficiency of the vehicle, resulting in poor use effect. Summary of the invention

[0004] The purpose of the present invention is to provide a vehicle-mounted single Beidou positioning terminal system, which is small in size, light in weight, easy to install and use, and has high accuracy and reliability. It can effectively improve the safety and operating efficiency of the vehicle, enhance the use effect, and solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A vehicle-mounted single Beidou positioning terminal system comprises a processor installed on the vehicle, a Beidou satellite navigation receiver and a memory, wherein the Beidou satellite navigation receiver is used to receive a signal sent from a Beidou satellite to the ground and determine the Beidou satellite signal; A processor, used to process Beidou satellite signals and determine vehicle location information; The memory is used to store Beidou satellite signals and vehicle location information.

[0006] Preferably, the Beidou satellite navigation receiver receives a signal sent by a Beidou satellite and performs the following operations: Based on the vehicle-mounted single Beidou positioning requirements, establish a signal transmission connection between the Beidou satellite navigation receiver and the Beidou satellite; Among them, the Beidou satellite navigation receiver transmits an instruction requesting to establish a signal transmission connection to the Beidou satellite, the Beidou satellite establishes an instruction of the signal transmission connection based on the request transmitted by the Beidou satellite navigation receiver, and the Beidou satellite transmits an instruction agreeing to establish the signal transmission connection to the Beidou satellite navigation receiver; The Beidou satellite navigation receiver receives an instruction transmitted by the Beidou satellite agreeing to establish a signal transmission connection, and the Beidou satellite navigation receiver establishes a signal transmission connection with the Beidou satellite based on the instruction transmitted by the Beidou satellite agreeing to establish a signal transmission connection; Among them, Beidou satellites send electromagnetic wave signals to the ground, and the Beidou satellite navigation receiver installed on the vehicle captures and receives the electromagnetic wave signals sent by the Beidou satellite, thereby determining the Beidou satellite signal.

[0007] Preferably, real-time monitoring of the signal transmission operation quality between the Beidou satellite navigation receiver and the Beidou satellite, and abnormal alarm when the signal transmission operation is abnormal, include: Real-time monitoring of the first signal transmission operating parameters and the second signal transmission operating parameters between the Beidou satellite navigation receiver and the Beidou satellite, wherein the first signal transmission operating parameters include the signal strength of each Beidou satellite, the signal transmission delay rate, the signal-to-noise ratio and the number of satellites; the second signal transmission operating parameters include the multipath signal fading amplitude, the multipath delay rate and the ratio of the reflected path signal to the direct path signal strength; Acquire a first operation evaluation coefficient between each Beidou satellite and the Beidou satellite navigation receiver using the first signal transmission operation parameter; The first operation evaluation coefficient corresponding to each Beidou satellite is obtained by the following formula: ; Among them, R 01 represents the first operation evaluation coefficient corresponding to each Beidou satellite; n represents the number of unit times of signal transmission between the Beidou satellite navigation receiver and each Beidou satellite, and the unit time is 1s; S i Indicates the Beidou satellite signal strength corresponding to the i-th Beidou satellite per unit time; SNR i Represents the signal-to-noise ratio per unit time of the i-th Beidou satellite; SNR x represents a preset signal-to-noise ratio reference value; ε represents a preset proportionality coefficient, and the value range of the proportionality coefficient is 0.001-0.008; Smax and S min Indicates the maximum and minimum values ​​of the Beidou satellite signal strength that appear in n unit time corresponding to each Beidou satellite; S b represents the standard deviation of BeiDou satellite signal strength in n units of time; P tb represents the standard deviation of the signal transmission delay rate of n units of time corresponding to each Beidou satellite; P tmax It represents the signal transmission delay rate corresponding to the maximum signal-to-noise ratio that occurs in n unit time for each Beidou satellite; Compare the first operation evaluation coefficient corresponding to each Beidou satellite with a preset first coefficient threshold; When the first operation evaluation coefficient corresponding to each Beidou satellite is lower than the preset first coefficient threshold, the second signal transmission operation parameter is called up, and the second signal transmission operation parameter is used to determine whether there is any abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite.

[0008] Preferably, when the first operation evaluation coefficient corresponding to each Beidou satellite is lower than a preset first coefficient threshold, a second signal transmission operation parameter is retrieved, and the second signal transmission operation parameter is used to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, including: When the first operation evaluation coefficient corresponding to any one of the multiple Beidou satellites is lower than the preset first coefficient threshold, the Beidou satellite corresponding to the first operation evaluation coefficient lower than the preset first coefficient threshold is taken as the target satellite; Retrieving the second signal transmission operation parameters of the target satellite; wherein the second signal transmission operation parameters of the target satellite include the multipath signal fading amplitude, the multipath delay rate, and the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; Acquire a second operation evaluation coefficient corresponding to the target satellite using the second signal transmission operation parameter of the target satellite; The second operation evaluation coefficient corresponding to the target satellite is obtained by the following formula: ; Among them, R 02m represents the second operation evaluation coefficient corresponding to the target satellite; D m Indicates the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; R m01 Represents the first operation evaluation coefficient corresponding to the target satellite; R y represents a preset first coefficient threshold; β represents an adjustment coefficient, and the value range of the adjustment coefficient is 0.38-1.17; M fm Indicates the proportional value of the multipath signal fading amplitude corresponding to the target satellite; Mtm represents the multipath delay rate corresponding to the target satellite; B mb Indicates the BeiDou satellite signal strength change rate corresponding to the target satellite in n unit time; Comparing a second operation evaluation coefficient corresponding to the target satellite with a preset second coefficient threshold; When the second operation evaluation coefficient corresponding to the target satellite exceeds a preset second coefficient threshold, a risk warning is only issued for the target satellite; When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, the second operation evaluation coefficients of other Beidou satellites except the target satellite are combined to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite.

[0009] Preferably, when the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, the second operation evaluation coefficients of other Beidou satellites except the target satellite are combined to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, including: When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, other Beidou satellites except the target satellite are used as observation satellites; Extracting the second signal transmission operation parameters corresponding to the observation satellite; wherein the second signal transmission operation parameters of the observation satellite include the multipath signal fading amplitude, the multipath delay rate and the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; Obtaining a second operation evaluation coefficient corresponding to the observation satellite using a second signal transmission operation parameter corresponding to the observation satellite; The second operation evaluation coefficient corresponding to the observation satellite is obtained by the following formula: ; Among them, R 02g represents the second operation evaluation coefficient corresponding to the observed satellite; D m Indicates the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; D g M represents the ratio of the reflected path signal to the direct path signal strength corresponding to the observed satellite; fg Indicates the proportional value of the multipath signal fading amplitude corresponding to the observed satellite; M tg represents the multipath delay rate corresponding to the observed satellite; B gb Indicates the Beidou satellite signal strength change rate corresponding to the observed satellite in n unit time; B mb Indicates the BeiDou satellite signal strength change rate corresponding to the target satellite in n unit time; Obtaining a comprehensive operation evaluation coefficient using the second operation evaluation coefficient corresponding to the observation satellite and the second operation evaluation coefficient corresponding to the target satellite; The comprehensive operation evaluation coefficient is obtained by the following formula: ; Among them, R z represents the comprehensive operation evaluation coefficient; m represents the number of observed satellites; R 02gi represents the second operation evaluation coefficient corresponding to the i-th observation satellite; R 02m represents the second operation evaluation coefficient corresponding to the target satellite; λ represents an adjustment factor, and the value range of the adjustment factor is 0.27-0.82; Comparing the comprehensive operation evaluation coefficient with a preset comprehensive coefficient threshold; When the comprehensive operation evaluation coefficient is lower than a preset comprehensive coefficient threshold, it is determined that there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, and an abnormality alarm is issued.

[0010] Preferably, the processor comprises: The signal processing module is used to decode the Beidou satellite signal, determine the Beidou satellite navigation data, and clean and optimize the Beidou satellite navigation data; The position calculation module is used to calculate the vehicle position information using a distance-based nearest neighbor algorithm.

[0011] Preferably, the signal processing module comprises: A signal decoding unit, used for decoding Beidou satellite signals; Get Beidou satellite signals and extract PN codes from Beidou satellite signals. Among them, PN code is the coding method used for randomizing signals in the Beidou satellite system; By identifying the PN code, the propagation delay and Doppler frequency shift information of the Beidou satellite signal are calculated; Based on the PN code and Beidou satellite signal, the pseudorange and pseudoscale are calculated; Among them, the pseudorange is the physical distance from the Beidou satellite to the Beidou satellite navigation receiver; The pseudo-scale is the angle from the Beidou satellite navigation receiver to the direction of the Beidou satellite; Based on pseudorange and pseudoscale, estimate the position and state of Beidou satellite, determine the Beidou satellite speed, calculate the position and speed of Beidou satellite, and extract and decode the navigation message of Beidou satellite; Among them, the navigation message includes the Beidou satellite’s timestamp, atomic clock error and service information; Determine Beidou satellite navigation data based on the position, speed and timestamp of Beidou satellite.

[0012] Preferably, extracting the PN code from the Beidou satellite signal includes: Synchronize the BeiDou satellite signal with the BeiDou satellite reference signal, set a localized PN code sequence on the BeiDou satellite navigation receiver, and match it with the BeiDou satellite PN code sequence; Depolarize the Beidou satellite signal to eliminate the distortion of the Beidou satellite signal caused by the earth's magnetic field; Perform noise reduction processing on Beidou satellite signals to eliminate noise and clutter in Beidou satellite signals; The Beidou satellite signal is modulated and processed to remove all frequency modulation components except the PN code in the Beidou satellite signal, and then the PN code is extracted.

[0013] Preferably, the signal processing module further includes: Data optimization unit, used to clean and optimize Beidou satellite navigation data; Obtain decoded Beidou satellite navigation data; Clean and optimize the decoded Beidou satellite navigation data, including: Conduct consistency check on Beidou satellite navigation data; According to the data consistency requirements, check whether the Beidou satellite navigation data contains inconsistent data that is useless for vehicle-mounted single Beidou positioning, and remove the inconsistent data in the Beidou satellite navigation data; Check the invalid and missing values ​​of Beidou satellite navigation data; According to the data validity and integrity requirements, check whether the Beidou satellite navigation data contains invalid values ​​and missing values ​​that are useless for vehicle-mounted single Beidou positioning, and remove the invalid values ​​and missing values ​​in the Beidou satellite navigation data; Determine the Beidou satellite navigation data that is useful for vehicle-mounted single Beidou positioning.

[0014] Preferably, the position calculation module includes: A plan making unit, used for making a vehicle position calculation plan; Obtain Beidou satellite navigation data useful for vehicle-mounted single Beidou positioning; Analyze the Beidou satellite navigation data that is useful for vehicle-mounted single Beidou positioning and develop a vehicle position calculation plan; A position calculation unit, used to accurately calculate the vehicle position; Obtain vehicle position calculation solution; The vehicle position is accurately calculated based on the vehicle position calculation solution.

[0015] Preferably, the vehicle position is accurately calculated by performing the following operations: The vehicle location information is calculated using the nearest neighbor algorithm based on distance; For the current vehicle, compare it with all reference stations and calculate the distances between them, and select the vehicle with the smallest sum of distances as the current hypothetical vehicle; According to the current position of the assumed vehicle and Beidou satellite navigation data, the distance-based nearest neighbor algorithm is used to update the position of the assumed vehicle and select new candidate vehicles, and the cycle is repeated until the stop condition is met; When the stopping condition is reached, the last position of the assumed vehicle is output, that is, the actual position of the vehicle, and then the vehicle position information is calculated.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention receives a signal sent from a Beidou satellite to the ground through a Beidou satellite navigation receiver, determines the Beidou satellite signal, decodes and processes the Beidou satellite signal through a processor, determines Beidou satellite navigation data, cleans and optimizes the Beidou satellite navigation data, analyzes the Beidou satellite navigation data, formulates a vehicle position calculation scheme, accurately calculates the vehicle position based on the vehicle position calculation scheme, determines the vehicle position information, and stores the Beidou satellite signal and the vehicle position information through a memory. The vehicle-mounted single Beidou positioning terminal system has small size, light weight, is easy to install and use, and has high accuracy and reliability, can effectively improve the safety and operation efficiency of the vehicle, and enhances the use effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a module architecture diagram of the vehicle-mounted single Beidou positioning terminal system of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In order to solve the problem that the existing vehicle-mounted positioning terminal has poor positioning reliability, cannot effectively improve the safety and operating efficiency of the vehicle, and leads to poor use effect, please refer to Figure 1 , this embodiment provides the following technical solutions: A vehicle-mounted single Beidou positioning terminal system comprises a processor, a Beidou satellite navigation receiver and a memory installed on the vehicle.

[0020] It should be noted that the Beidou satellite navigation receiver receives the signal sent from the Beidou satellite to the ground to determine the Beidou satellite signal; the processor processes the Beidou satellite signal to determine the vehicle position information; the memory stores the Beidou satellite signal and the vehicle position information. The vehicle-mounted single Beidou positioning terminal system is small in size, light in weight, easy to install and use, and has high accuracy and reliability, which can effectively improve the safety and operation efficiency of the vehicle.

[0021] In this embodiment, the Beidou satellite navigation receiver receives a signal sent by a Beidou satellite, including: Based on the vehicle-mounted single Beidou positioning requirements, establish a signal transmission connection between the Beidou satellite navigation receiver and the Beidou satellite; Among them, the Beidou satellite navigation receiver transmits an instruction requesting to establish a signal transmission connection to the Beidou satellite, the Beidou satellite establishes an instruction of the signal transmission connection based on the request transmitted by the Beidou satellite navigation receiver, and the Beidou satellite transmits an instruction agreeing to establish the signal transmission connection to the Beidou satellite navigation receiver; The Beidou satellite navigation receiver receives an instruction transmitted by the Beidou satellite agreeing to establish a signal transmission connection, and the Beidou satellite navigation receiver establishes a signal transmission connection with the Beidou satellite based on the instruction transmitted by the Beidou satellite agreeing to establish a signal transmission connection; Among them, Beidou satellites send electromagnetic wave signals to the ground, and the Beidou satellite navigation receiver installed on the vehicle captures and receives the electromagnetic wave signals sent by the Beidou satellite, thereby determining the Beidou satellite signal.

[0022] Specifically, the signal transmission quality between the Beidou satellite navigation receiver and the Beidou satellite is monitored in real time, and an abnormal alarm is issued when the signal transmission operation is abnormal, including: Real-time monitoring of the first signal transmission operating parameters and the second signal transmission operating parameters between the Beidou satellite navigation receiver and the Beidou satellite, wherein the first signal transmission operating parameters include the signal strength of each Beidou satellite, the signal transmission delay rate, the signal-to-noise ratio and the number of satellites; the second signal transmission operating parameters include the multipath signal fading amplitude, the multipath delay rate and the ratio of the reflected path signal to the direct path signal strength; Acquire a first operation evaluation coefficient between each Beidou satellite and the Beidou satellite navigation receiver using the first signal transmission operation parameter; The first operation evaluation coefficient corresponding to each Beidou satellite is obtained by the following formula: ; Among them, R 01represents the first operation evaluation coefficient corresponding to each Beidou satellite; n represents the number of unit times of signal transmission between the Beidou satellite navigation receiver and each Beidou satellite, and the unit time is 1s; S i Indicates the Beidou satellite signal strength corresponding to the i-th Beidou satellite per unit time; SNR i Represents the signal-to-noise ratio per unit time of the i-th Beidou satellite; SNR x represents a preset signal-to-noise ratio reference value; ε represents a preset proportionality coefficient, and the value range of the proportionality coefficient is 0.001-0.008; S max and S min Indicates the maximum and minimum values ​​of the Beidou satellite signal strength that appear in n unit time corresponding to each Beidou satellite; S b represents the standard deviation of BeiDou satellite signal strength in n units of time; P tb represents the standard deviation of the signal transmission delay rate of n units of time corresponding to each Beidou satellite; P tmax It represents the signal transmission delay rate corresponding to the maximum signal-to-noise ratio that occurs in n unit time for each Beidou satellite; Compare the first operation evaluation coefficient corresponding to each Beidou satellite with a preset first coefficient threshold; When the first operation evaluation coefficient corresponding to each Beidou satellite is lower than the preset first coefficient threshold, the second signal transmission operation parameter is called up, and the second signal transmission operation parameter is used to determine whether there is any abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite.

[0023] The technical effect of the above technical solution is: by real-time monitoring of the first signal transmission operation parameters (such as signal strength, signal transmission delay rate, signal-to-noise ratio and number of satellites) and the second signal transmission operation parameters (such as multipath signal fading amplitude, multipath delay rate and the ratio of reflected path signal to direct path signal strength) between the Beidou satellite navigation receiver and the Beidou satellite, the operation status of the signal transmission can be fully and accurately grasped. The first operation evaluation coefficient calculated by the first signal transmission operation parameter can quantitatively evaluate the signal transmission quality between each Beidou satellite and the receiver, and provide accurate data support for subsequent abnormal judgment. By comparing the first operation evaluation coefficient with the preset first coefficient threshold, when the evaluation coefficient is lower than the threshold, the abnormal alarm mechanism can be quickly triggered to achieve a rapid response to the signal transmission abnormality. After confirming that the first signal transmission operation parameter is abnormal, the second signal transmission operation parameter is further retrieved for judgment, which increases the hierarchy and accuracy of the abnormal judgment and reduces the possibility of false alarms and missed alarms. The parameters involved in the formula (such as signal strength, signal-to-noise ratio, signal transmission delay rate, etc.) all take into account the influence of time changes. By performing statistics and analysis on multiple data points within a unit time (such as 1 second), the stability and reliability of the evaluation results are improved. The value range of the proportional coefficient ε (0.001-0.008) provides a certain flexibility for the algorithm, which can be adjusted according to actual conditions to meet the application requirements in different scenarios. By comprehensively considering multiple factors such as the maximum value, minimum value, standard deviation of signal strength, and the standard deviation and maximum value of signal transmission delay rate, the algorithm can more comprehensively reflect the operating status of signal transmission and improve the robustness of the system. This technical solution can monitor and quickly respond to signal transmission anomalies in real time, which helps to take timely measures to avoid or reduce navigation positioning errors or failures caused by signal transmission problems. By quantitatively evaluating the quality of signal transmission, it provides strong data support for system maintenance and optimization, and helps to improve the overall performance and user experience of the Beidou satellite navigation system.

[0024] To sum up, the technical solution demonstrates technical effects such as real-time monitoring, precise evaluation, sensitivity and accuracy of abnormal warning, adaptability and robustness, as well as high efficiency and practicality in terms of performance indicators, which is of great significance for improving the reliability and stability of the Beidou satellite navigation system.

[0025] Specifically, when the first operation evaluation coefficient corresponding to each Beidou satellite is lower than the preset first coefficient threshold, the second signal transmission operation parameter is retrieved, and the second signal transmission operation parameter is used to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, including: When the first operation evaluation coefficient corresponding to any one of the multiple Beidou satellites is lower than the preset first coefficient threshold, the Beidou satellite corresponding to the first operation evaluation coefficient lower than the preset first coefficient threshold is taken as the target satellite; Retrieving the second signal transmission operation parameters of the target satellite; wherein the second signal transmission operation parameters of the target satellite include the multipath signal fading amplitude, the multipath delay rate, and the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; Acquire a second operation evaluation coefficient corresponding to the target satellite using the second signal transmission operation parameter of the target satellite; The second operation evaluation coefficient corresponding to the target satellite is obtained by the following formula: ; Among them, R 02m represents the second operation evaluation coefficient corresponding to the target satellite; D m Indicates the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; R m01 Represents the first operation evaluation coefficient corresponding to the target satellite; R y represents a preset first coefficient threshold; β represents an adjustment coefficient, and the value range of the adjustment coefficient is 0.38-1.17; M fm Indicates the proportional value of the multipath signal fading amplitude corresponding to the target satellite; M tm represents the multipath delay rate corresponding to the target satellite; B mb Indicates the BeiDou satellite signal strength change rate corresponding to the target satellite in n unit time; Comparing a second operation evaluation coefficient corresponding to the target satellite with a preset second coefficient threshold; When the second operation evaluation coefficient corresponding to the target satellite exceeds a preset second coefficient threshold, a risk warning is only issued for the target satellite; When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, the second operation evaluation coefficients of other Beidou satellites except the target satellite are combined to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite.

[0026] The technical effect of the above technical solution is: by first monitoring the first signal transmission operation parameter and calculating the first operation evaluation coefficient, the Beidou satellite (i.e., the target satellite) that may have an abnormality can be preliminarily screened out. This step effectively reduces unnecessary comprehensive inspections and improves monitoring efficiency. When the first operation evaluation coefficient is lower than the preset threshold, the second signal transmission operation parameter of the target satellite is retrieved for further analysis. This hierarchical monitoring method makes the abnormal positioning more accurate and helps to quickly lock the source of the problem. The calculation of the second operation evaluation coefficient comprehensively considers multiple factors such as the multipath signal fading amplitude, the multipath delay rate, the ratio of the reflected path signal to the direct path signal strength, and the signal strength change rate, providing comprehensive data support for evaluating the signal transmission quality of the target satellite. By comparing the second operation evaluation coefficient with the preset second coefficient threshold, risk warning of the target satellite can be achieved. This comprehensive evaluation method improves the accuracy of the warning and helps to take timely measures to avoid or mitigate potential signal transmission problems. The value range of the adjustment coefficient β (0.38-1.17) provides a certain flexibility for the algorithm, which can be adjusted according to actual application scenarios and needs to adapt to different signal transmission environments and conditions. This technical solution not only takes into account the abnormal conditions of the target satellite, but also combines the second operation evaluation coefficients of other Beidou satellites for comprehensive judgment, thus improving the overall robustness and reliability of the system. This technical solution realizes real-time monitoring and abnormal warning of the signal transmission quality between Beidou satellite navigation receivers and Beidou satellites through layered monitoring and comprehensive evaluation, which helps to timely discover and deal with potential signal transmission problems. At the same time, this technical solution also has certain practicality and can be applied to various scenarios that require high-precision navigation and positioning, providing strong guarantees for users' navigation and positioning needs.

[0027] To sum up, this technical solution demonstrates technical effects such as layered monitoring and precise positioning of anomalies, comprehensive assessment and risk warning, flexibility and robustness, as well as high efficiency and practicality in terms of performance indicators, which is of great significance for improving the stability and reliability of the Beidou satellite navigation system.

[0028] Specifically, when the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, the second operation evaluation coefficients of other Beidou satellites except the target satellite are combined to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, including: When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, other Beidou satellites except the target satellite are used as observation satellites; Extracting the second signal transmission operation parameters corresponding to the observation satellite; wherein the second signal transmission operation parameters of the observation satellite include the multipath signal fading amplitude, the multipath delay rate and the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; Obtaining a second operation evaluation coefficient corresponding to the observation satellite using a second signal transmission operation parameter corresponding to the observation satellite; The second operation evaluation coefficient corresponding to the observation satellite is obtained by the following formula: ; Among them, R 02g represents the second operation evaluation coefficient corresponding to the observed satellite; D m Indicates the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; D g M represents the ratio of the reflected path signal to the direct path signal strength corresponding to the observed satellite; fg Indicates the proportional value of the multipath signal fading amplitude corresponding to the observed satellite; M tg represents the multipath delay rate corresponding to the observed satellite; B gb Indicates the Beidou satellite signal strength change rate corresponding to the observed satellite in n unit time; B mb Indicates the BeiDou satellite signal strength change rate corresponding to the target satellite in n unit time; Obtaining a comprehensive operation evaluation coefficient using the second operation evaluation coefficient corresponding to the observation satellite and the second operation evaluation coefficient corresponding to the target satellite; The comprehensive operation evaluation coefficient is obtained by the following formula: ; Among them, R z represents the comprehensive operation evaluation coefficient; m represents the number of observed satellites; R 02gi represents the second operation evaluation coefficient corresponding to the i-th observation satellite; R 02m represents the second operation evaluation coefficient corresponding to the target satellite; λ represents an adjustment factor, and the value range of the adjustment factor is 0.27-0.82; Comparing the comprehensive operation evaluation coefficient with a preset comprehensive coefficient threshold; When the comprehensive operation evaluation coefficient is lower than a preset comprehensive coefficient threshold, it is determined that there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, and an abnormality alarm is issued.

[0029] The technical effect of the above technical solution is: the technical solution not only focuses on the second operation evaluation coefficient of the target satellite (i.e., the satellite that is initially judged to be abnormal), but also considers the second operation evaluation coefficients of other observation satellites, and realizes comprehensive monitoring of the signal transmission quality between the Beidou satellite navigation receiver and all Beidou satellites. By calculating the comprehensive operation evaluation coefficient, the evaluation results of the target satellite and the observation satellite are combined to provide more comprehensive and accurate data support for determining whether there is an abnormality in the signal transmission operation. The calculation of the comprehensive operation evaluation coefficient takes into account multiple factors, including the ratio of the reflected path signal to the direct path signal strength, the proportional value of the multipath signal fading amplitude, the multipath delay rate, and the Beidou satellite signal strength change rate, etc. These factors jointly reflect the quality of signal transmission. Comparing the comprehensive operation evaluation coefficient with the preset comprehensive coefficient threshold can more accurately determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, reducing the possibility of false alarms and missed alarms. The technical solution determines the abnormality of signal transmission by combining the evaluation results of multiple satellites, thereby enhancing the robustness of the system. Even if the evaluation results of individual satellites are interfered with or erroneous, it will not have a significant impact on the overall determination result. At the same time, by adjusting the preset coefficient threshold, the technical solution can adapt to different application scenarios and signal transmission environments, improving the flexibility and adaptability of the system. The technical solution realizes real-time monitoring and abnormality judgment of signal transmission quality, can find potential problems at the first time, and helps to take timely measures to avoid or reduce the impact of signal transmission abnormalities on navigation positioning accuracy. Through hierarchical monitoring and comprehensive evaluation, the technical solution improves monitoring efficiency, reduces unnecessary comprehensive inspections, and reduces the consumption of system resources.

[0030] To sum up, this technical solution demonstrates technical effects such as comprehensive monitoring and comprehensive evaluation, accuracy of anomaly judgment, system robustness, high efficiency and real-time performance, and practicality in terms of performance indicators, which is of great significance for improving the overall performance and user experience of the Beidou satellite navigation system.

[0031] In this embodiment, the processor includes: a signal processing module and a position calculation module.

[0032] It should be noted that the Beidou satellite signal is decoded and processed through the signal processing module to determine the Beidou satellite navigation data, and the Beidou satellite navigation data is cleaned and optimized; the vehicle position information is calculated by the position calculation module using a distance-based nearest neighbor algorithm, which has high accuracy and reliability.

[0033] In this embodiment, the signal processing module includes: A signal decoding unit, used for decoding Beidou satellite signals; It should be noted that decoding is a process of using a specific method to restore digital data to the content it represents or convert electrical pulse signals, optical signals, radio waves, etc. into the information, data, etc. they represent; decoding is the process of the receiver restoring the received symbols or codes to information, which corresponds to the encoding process. In a computer network, the network interconnects computers through a communication network to achieve resource sharing and data transmission. When the signal form of the communication network used is different from the signal form of the transmission equipment, the signal form must be converted. Generally, the signal form conversion performed by the sender is called encoding, and the signal form conversion performed by the receiver is called decoding.

[0034] Specifically, obtain Beidou satellite signals, extract PN codes from Beidou satellite signals, Among them, PN code is the coding method used for randomizing signals in the Beidou satellite system; It should be noted that the PN code is a coding sequence composed of 0 and 1 with autocorrelation properties similar to white noise. The Beidou satellite transmitter and Beidou satellite navigation receiver use a high-precision and high-stability clock frequency source to ensure the stability of frequency and phase. However, in practical applications, there are many uncertain factors that cannot be estimated in advance, such as unstable receiving and transmitting clocks, uncertain transmission time, channel transmission delay and interference, etc., especially in mobile communications. These uncertain factors are random and cannot be compensated in advance. They can only be eliminated through the synchronization system. Therefore, in CDMA spread spectrum communication, the synchronization system is essential.

[0035] By identifying the PN code, the propagation delay and Doppler frequency shift information of the Beidou satellite signal are calculated; It should be noted that Doppler shift refers to the change in phase and frequency caused by the difference in propagation distance when a mobile station moves in a certain direction at a constant speed. This change is usually called Doppler shift. It reveals the law that the properties of waves change during motion. When moving in front of the wave source, the wave is compressed, the wavelength becomes shorter, and the frequency becomes higher; when moving behind the wave source, the opposite effect occurs, the wavelength becomes longer, and the frequency becomes lower.

[0036] Based on the PN code and Beidou satellite signal, the pseudorange and pseudoscale are calculated; Among them, the pseudorange is the physical distance from the Beidou satellite to the Beidou satellite navigation receiver; The pseudo-scale is the angle from the Beidou satellite navigation receiver to the direction of the Beidou satellite; Based on pseudorange and pseudoscale, estimate the position and state of Beidou satellite, determine the Beidou satellite speed, calculate the position and speed of Beidou satellite, and extract and decode the navigation message of Beidou satellite; Among them, the navigation message includes the Beidou satellite’s timestamp, atomic clock error and service information; Determine Beidou satellite navigation data based on the position, speed and timestamp of Beidou satellite.

[0037] In this embodiment, extracting the PN code from the Beidou satellite signal includes: Synchronize the BeiDou satellite signal with the BeiDou satellite reference signal, set a localized PN code sequence on the BeiDou satellite navigation receiver, and match it with the BeiDou satellite PN code sequence; Depolarize the Beidou satellite signal to eliminate the distortion of the Beidou satellite signal caused by the earth's magnetic field; Perform noise reduction processing on Beidou satellite signals to eliminate noise and clutter in Beidou satellite signals; The Beidou satellite signal is modulated and processed to remove all frequency modulation components except the PN code in the Beidou satellite signal, and then the PN code is extracted.

[0038] In this embodiment, the process of calculating the pseudorange and pseudoscale based on the PN code and the Beidou satellite signal is generally referred to as "pseudorange positioning (PDL)", which is one of the key technologies of the global navigation satellite system. The following is a method for calculating the pseudorange and pseudoscale: First, it is necessary to extract the PN code sequence from the received Beidou satellite signal. The PN code is an artificially injected code sequence used to distinguish different time and space sampling points in the signal. By comparing the received PN code with the known PN reference code, the pseudorange (PR) can be obtained. Then, the pseudo-range (PR) can be used to calculate the pseudo-scale (PS), which is a linear transformation of the pseudo-range that provides the exact location of the measurement point. The pseudo-scale is calculated as: PS = 2 * (PR^2 - 1) / ((PR + 1)^2 - 1) When calculating pseudo-scale, the Doppler effect needs to be considered. The Doppler effect is caused by the change in signal frequency due to the relative motion between the receiver and the satellite. In order to avoid the influence of the Doppler effect, the pseudo-range needs to be appropriately corrected. A commonly used correction method is to use the Doppler shift model (PMM) of the pseudo-range; the Doppler shift model assumes that the frequency of the satellite transmission is constant near the receiver. Therefore, the Doppler shift model of the pseudo-range can be used to convert the pseudo-range (PR) into the pseudo-scale (PS). The calculation formula of the pseudo-scale (PS) is: PS_corrected = PS / (1 + 2 *V_OR / c) Where V_OR is the average relative velocity between the receiver and the satellite, c is the speed of light (approximately 3*10^8 m / s), and PS_corrected is the pseudo-scale after Doppler correction; Specifically, the calculation of pseudo-range and pseudo-scale involves complex mathematical operations and high-precision timing and frequency measurements. In practical applications, high-performance signal processors and software tools are usually required.

[0039] In this embodiment, the signal processing module further includes: Data optimization unit, used to clean and optimize Beidou satellite navigation data; Obtain decoded Beidou satellite navigation data; Clean and optimize the decoded Beidou satellite navigation data, including: Conduct consistency check on Beidou satellite navigation data; According to the data consistency requirements, check whether the Beidou satellite navigation data contains inconsistent data that is useless for vehicle-mounted single Beidou positioning, and remove the inconsistent data in the Beidou satellite navigation data; Check the invalid and missing values ​​of Beidou satellite navigation data; According to the data validity and integrity requirements, check whether the Beidou satellite navigation data contains invalid values ​​and missing values ​​that are useless for vehicle-mounted single Beidou positioning, and remove the invalid values ​​and missing values ​​in the Beidou satellite navigation data; Determine the Beidou satellite navigation data that is useful for vehicle-mounted single Beidou positioning.

[0040] It should be noted that by cleaning and optimizing the Beidou satellite navigation data, inconsistent data, invalid values ​​and missing values ​​that are useless for the on-board single Beidou positioning can be removed, and the Beidou satellite navigation data that is useful for the on-board single Beidou positioning can be determined. The calculation accuracy and efficiency of subsequent Beidou satellite navigation data can be improved, so that the on-board single Beidou positioning terminal system has higher accuracy and reliability, which can effectively improve the safety and operation efficiency of the vehicle.

[0041] In this embodiment, the position calculation module includes: A plan making unit, used for making a vehicle position calculation plan; Obtain Beidou satellite navigation data useful for vehicle-mounted single Beidou positioning; Analyze the Beidou satellite navigation data that is useful for vehicle-mounted single Beidou positioning and develop a vehicle position calculation plan; A position calculation unit, used to accurately calculate the vehicle position; Obtain vehicle position calculation solution; The vehicle position is accurately calculated based on the vehicle position calculation solution.

[0042] Specifically, to accurately calculate the vehicle position, perform the following operations: The vehicle location information is calculated using the nearest neighbor algorithm based on distance; For the current vehicle, compare it with all reference stations and calculate the distances between them, and select the vehicle with the smallest sum of distances as the current hypothetical vehicle; According to the current position of the assumed vehicle and Beidou satellite navigation data, the distance-based nearest neighbor algorithm is used to update the position of the assumed vehicle and select new candidate vehicles, and the cycle is repeated until the stop condition is met; When the stopping condition is reached, the last position of the assumed vehicle is output, that is, the actual position of the vehicle, and then the vehicle position information is calculated.

[0043] It should be noted that by decoding the Beidou satellite signal through the processor, determining the Beidou satellite navigation data, and cleaning and optimizing the Beidou satellite navigation data, the calculation accuracy and efficiency of the subsequent Beidou satellite navigation data can be improved. By analyzing the Beidou satellite navigation data, a vehicle position calculation plan is formulated, and the vehicle position is accurately calculated based on the vehicle position calculation plan to determine the vehicle position information. By storing the Beidou satellite signal and vehicle position information in the memory, the vehicle-mounted single Beidou positioning terminal system can be small in size, light in weight, easy to install and use, and has high accuracy and reliability, which can effectively improve the safety and operating efficiency of the vehicle and improve the use effect.

[0044] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0045] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A vehicle-mounted single Beidou positioning terminal system, comprising a processor, a Beidou satellite navigation receiver and a memory installed on the vehicle, characterized in that: The Beidou satellite navigation receiver is used to receive signals sent from Beidou satellites to the ground and determine Beidou satellite signals; A processor, used to process Beidou satellite signals and determine vehicle location information; A memory for storing Beidou satellite signals and vehicle location information; The Beidou satellite navigation receiver receives the signal sent by the Beidou satellite and performs the following operations: Based on the vehicle-mounted single Beidou positioning requirements, establish a signal transmission connection between the Beidou satellite navigation receiver and the Beidou satellite; Among them, the Beidou satellite navigation receiver transmits an instruction requesting to establish a signal transmission connection to the Beidou satellite, the Beidou satellite establishes an instruction of the signal transmission connection based on the request transmitted by the Beidou satellite navigation receiver, and the Beidou satellite transmits an instruction agreeing to establish the signal transmission connection to the Beidou satellite navigation receiver; The Beidou satellite navigation receiver receives an instruction transmitted by the Beidou satellite agreeing to establish a signal transmission connection, and the Beidou satellite navigation receiver establishes a signal transmission connection with the Beidou satellite based on the instruction transmitted by the Beidou satellite agreeing to establish a signal transmission connection; Among them, Beidou satellites send electromagnetic wave signals to the ground, and the Beidou satellite navigation receiver installed on the vehicle captures and receives the electromagnetic wave signals sent by the Beidou satellite, thereby determining the Beidou satellite signal.

2. A vehicle-mounted single Beidou positioning terminal system according to claim 1, characterized in that: Real-time monitoring of the signal transmission quality between the Beidou satellite navigation receiver and the Beidou satellite, and abnormal alarm when the signal transmission is abnormal, including: Real-time monitoring of the first signal transmission operating parameters and the second signal transmission operating parameters between the Beidou satellite navigation receiver and the Beidou satellite, wherein the first signal transmission operating parameters include the signal strength of each Beidou satellite, the signal transmission delay rate, the signal-to-noise ratio and the number of satellites; the second signal transmission operating parameters include the multipath signal fading amplitude, the multipath delay rate and the ratio of the reflected path signal to the direct path signal strength; Acquire a first operation evaluation coefficient between each Beidou satellite and the Beidou satellite navigation receiver using the first signal transmission operation parameter; The first operation evaluation coefficient corresponding to each Beidou satellite is obtained by the following formula: ； Among them, R 01 represents the first operation evaluation coefficient corresponding to each Beidou satellite; n represents the number of unit times of signal transmission between the Beidou satellite navigation receiver and each Beidou satellite, and the unit time is 1s; S i Indicates the Beidou satellite signal strength corresponding to the i-th unit time of each Beidou satellite; SNR i Represents the signal-to-noise ratio per unit time of the i-th Beidou satellite; SNR x represents a preset signal-to-noise ratio reference value; ε represents a preset proportionality coefficient, and the value range of the proportionality coefficient is 0.001-0.008; S max and S min Indicates the maximum and minimum values ​​of the Beidou satellite signal strength that appear in n unit time corresponding to each Beidou satellite; S b represents the standard deviation of BeiDou satellite signal strength in n units of time; P tb represents the standard deviation of the signal transmission delay rate of n units of time corresponding to each Beidou satellite; P tmax It represents the signal transmission delay rate corresponding to the maximum signal-to-noise ratio that occurs in n unit time for each Beidou satellite; Compare the first operation evaluation coefficient corresponding to each Beidou satellite with a preset first coefficient threshold; When the first operation evaluation coefficient corresponding to each Beidou satellite is lower than the preset first coefficient threshold, the second signal transmission operation parameter is called up, and the second signal transmission operation parameter is used to determine whether there is any abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite.

3. A vehicle-mounted single Beidou positioning terminal system according to claim 2, characterized in that: When the first operation evaluation coefficient corresponding to each Beidou satellite is lower than the preset first coefficient threshold, the second signal transmission operation parameter is retrieved, and the second signal transmission operation parameter is used to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, including: When the first operation evaluation coefficient corresponding to any one of the multiple Beidou satellites is lower than the preset first coefficient threshold, the Beidou satellite corresponding to the first operation evaluation coefficient lower than the preset first coefficient threshold is taken as the target satellite; Retrieving the second signal transmission operation parameters of the target satellite; wherein the second signal transmission operation parameters of the target satellite include the multipath signal fading amplitude, the multipath delay rate, and the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; Acquire a second operation evaluation coefficient corresponding to the target satellite using the second signal transmission operation parameter of the target satellite; The second operation evaluation coefficient corresponding to the target satellite is obtained by the following formula: ； Among them, R 02m represents the second operation evaluation coefficient corresponding to the target satellite; D m Indicates the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; R m01 Represents the first operation evaluation coefficient corresponding to the target satellite; R y represents a preset first coefficient threshold; β represents an adjustment coefficient, and the value range of the adjustment coefficient is 0.38-1.17; M fm Indicates the proportional value of the multipath signal fading amplitude corresponding to the target satellite; M tm represents the multipath delay rate corresponding to the target satellite; B mb Indicates the Beidou satellite signal strength change rate corresponding to the target satellite in n unit time; Comparing a second operation evaluation coefficient corresponding to the target satellite with a preset second coefficient threshold; When the second operation evaluation coefficient corresponding to the target satellite exceeds a preset second coefficient threshold, a risk warning is only issued for the target satellite; When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, the second operation evaluation coefficients of other Beidou satellites except the target satellite are combined to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite.

4. The vehicle-mounted single Beidou positioning terminal system according to claim 3 is characterized in that: When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, the second operation evaluation coefficients of other Beidou satellites except the target satellite are combined to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, including: When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, other Beidou satellites except the target satellite are used as observation satellites; Extracting the second signal transmission operation parameters corresponding to the observation satellite; wherein the second signal transmission operation parameters of the observation satellite include the multipath signal fading amplitude, the multipath delay rate and the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; Obtaining a second operation evaluation coefficient corresponding to the observation satellite using a second signal transmission operation parameter corresponding to the observation satellite; The second operation evaluation coefficient corresponding to the observation satellite is obtained by the following formula: ； Among them, R 02g represents the second operation evaluation coefficient corresponding to the observed satellite; D m Indicates the ratio of the reflected path signal to the direct path signal strength corresponding to the target satellite; D g M represents the ratio of the reflected path signal to the direct path signal strength corresponding to the observed satellite; fg Indicates the proportional value of the multipath signal fading amplitude corresponding to the observed satellite; M tg represents the multipath delay rate corresponding to the observed satellite; B gb Indicates the Beidou satellite signal strength change rate corresponding to the observed satellite in n unit time; B mb Indicates the Beidou satellite signal strength change rate corresponding to the target satellite in n unit time; Obtaining a comprehensive operation evaluation coefficient using the second operation evaluation coefficient corresponding to the observation satellite and the second operation evaluation coefficient corresponding to the target satellite; The comprehensive operation evaluation coefficient is obtained by the following formula: ； Among them, R z represents the comprehensive operation evaluation coefficient; m represents the number of observed satellites; R 02gi represents the second operation evaluation coefficient corresponding to the i-th observation satellite; R 02m represents the second operation evaluation coefficient corresponding to the target satellite; λ represents an adjustment factor, and the value range of the adjustment factor is 0.27-0.82; Comparing the comprehensive operation evaluation coefficient with a preset comprehensive coefficient threshold; When the comprehensive operation evaluation coefficient is lower than a preset comprehensive coefficient threshold, it is determined that there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, and an abnormality alarm is issued.

5. The vehicle-mounted single Beidou positioning terminal system according to claim 1, characterized in that: The processor comprises: The signal processing module is used to decode the Beidou satellite signal, determine the Beidou satellite navigation data, and clean and optimize the Beidou satellite navigation data; The position calculation module is used to calculate the vehicle position information using a distance-based nearest neighbor algorithm.

6. The vehicle-mounted single Beidou positioning terminal system according to claim 5, characterized in that: The signal processing module comprises: A signal decoding unit, used for decoding Beidou satellite signals; Obtain Beidou satellite signals and extract PN codes from Beidou satellite signals; Among them, PN code is the coding method used for randomizing signals in the Beidou satellite system; By identifying the PN code, the propagation delay and Doppler frequency shift information of the Beidou satellite signal are calculated; Based on the PN code and Beidou satellite signal, the pseudorange and pseudoscale are calculated; Among them, the pseudorange is the physical distance from the Beidou satellite to the Beidou satellite navigation receiver; The pseudo-scale is the angle from the Beidou satellite navigation receiver to the Beidou satellite direction; Based on pseudorange and pseudoscale, estimate the position and state of Beidou satellite, determine the Beidou satellite speed, calculate the position and speed of Beidou satellite, and extract and decode the navigation message of Beidou satellite; Among them, the navigation message includes the Beidou satellite’s timestamp, atomic clock error and service information; Determine Beidou satellite navigation data based on the position, speed and timestamp of Beidou satellite.

7. The vehicle-mounted single Beidou positioning terminal system according to claim 6, characterized in that: Extract PN code from Beidou satellite signal, including: Synchronize the BeiDou satellite signal with the BeiDou satellite reference signal, set a localized PN code sequence on the BeiDou satellite navigation receiver, and match it with the BeiDou satellite PN code sequence; Depolarize the Beidou satellite signal to eliminate the distortion of the Beidou satellite signal caused by the earth's magnetic field; Perform noise reduction processing on Beidou satellite signals to eliminate noise and clutter in Beidou satellite signals; The Beidou satellite signal is modulated and processed to remove all frequency modulation components except the PN code in the Beidou satellite signal, and then the PN code is extracted.

8. The vehicle-mounted single Beidou positioning terminal system according to claim 5, characterized in that: The signal processing module further includes: Data optimization unit, used to clean and optimize Beidou satellite navigation data; Obtain decoded Beidou satellite navigation data; Clean and optimize the decoded Beidou satellite navigation data, including: Conduct consistency check on Beidou satellite navigation data; According to the data consistency requirements, check whether the Beidou satellite navigation data contains inconsistent data that is useless for vehicle-mounted single Beidou positioning, and remove the inconsistent data in the Beidou satellite navigation data; Check the invalid and missing values ​​of Beidou satellite navigation data; According to the data validity and integrity requirements, check whether the Beidou satellite navigation data contains invalid values ​​and missing values ​​that are useless for vehicle-mounted single Beidou positioning, and remove the invalid values ​​and missing values ​​in the Beidou satellite navigation data; Determine the Beidou satellite navigation data that is useful for vehicle-mounted single Beidou positioning.

9. The vehicle-mounted single Beidou positioning terminal system according to claim 5, characterized in that: The position calculation module comprises: A plan making unit, used for making a vehicle position calculation plan; Obtain Beidou satellite navigation data useful for vehicle-mounted single Beidou positioning; Analyze the Beidou satellite navigation data that is useful for vehicle-mounted single Beidou positioning and develop a vehicle position calculation plan; A position calculation unit, used to accurately calculate the vehicle position; Obtain vehicle position calculation solution; The vehicle position is accurately calculated based on the vehicle position calculation solution.

10. The vehicle-mounted single Beidou positioning terminal system according to claim 9, characterized in that: To accurately calculate the vehicle position, perform the following operations: The vehicle location information is calculated using the nearest neighbor algorithm based on distance; For the current vehicle, compare it with all reference stations and calculate the distance, and select the vehicle with the smallest sum of distances as the current hypothetical vehicle; According to the current position of the assumed vehicle and Beidou satellite navigation data, the distance-based nearest neighbor algorithm is used to update the position of the assumed vehicle and select new candidate vehicles, and the cycle is repeated until the stop condition is met; When the stopping condition is reached, the last position of the assumed vehicle is output, that is, the actual position of the vehicle, and then the vehicle position information is calculated.

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