A vehicle-mounted single Beidou positioning terminal system

Abstract

The present invention discloses an in-vehicle single Beidou positioning terminal system, belonging to the technical field of vehicle positioning. It includes a processor, a Beidou satellite navigation receiver and a memory installed on the vehicle. The Beidou satellite navigation receiver is used to receive the signals sent by Beidou satellites to the ground and determine the Beidou satellite signals. The processor is used to process the Beidou satellite signals and determine the vehicle position information. The memory is used to store the Beidou satellite signals and the vehicle position information. The present invention solves the problems of the existing in-vehicle positioning terminal, such as poor positioning reliability and inability to effectively improve the safety and operation efficiency of vehicles. By receiving the signals sent by Beidou satellites to the ground through the Beidou satellite navigation receiver and determining the Beidou satellite signals, and processing the Beidou satellite signals through the processor to determine the vehicle position information, the present invention has high precision and reliability, can effectively improve the safety and operation efficiency of vehicles, and enhance the use effect.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle positioning, and specifically 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; by using wireless communication and network technologies, as well as advanced sensing devices, various types of vehicle information are collected, analyzed, and processed to achieve effective management and efficient utilization of vehicles; among them, the vehicle-mounted positioning terminal is an important device for collecting vehicle position information, mainly completing vehicle tracking and route planning.

[0003] Chinese Patent with publication number CN105510947B discloses a vehicle-mounted positioning terminal and a vehicle-mounted positioning method. Among them, 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 service logic unit; the service logic unit is used to determine whether to turn on the GPS hardware module according to the shutdown cycle of the GPS hardware module and the obtained motion parameters of the vehicle-mounted positioning terminal; the GPS hardware module is used to collect positioning information of the location where the vehicle-mounted positioning terminal is located during the operation cycle; the service logic unit is also used to obtain and process the positioning information collected by the GPS hardware module, and send the processed information to the communication hardware module; the communication hardware module is used to send the information processed by the service logic unit to an external communication server or a 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, this patent has the following defects:

[0004] For existing vehicle-mounted positioning terminals, their positioning reliability is poor, and they cannot effectively improve the safety and operation efficiency of vehicles, resulting in poor use effects. Summary of the Invention

[0005] 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 operation efficiency of vehicles, enhance the use effect, and solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A vehicle-mounted single Beidou positioning terminal system includes a processor, a Beidou satellite navigation receiver, and a memory installed on a vehicle. The Beidou satellite navigation receiver is used to receive signals sent by Beidou satellites to the ground and determine Beidou satellite signals;

[0008] The processor is used to process the Beidou satellite signals and determine the vehicle position information;

[0009] A memory for storing Beidou satellite signals and vehicle position information.

[0010] Preferably, the Beidou satellite navigation receiver receives the signals sent by Beidou satellites and performs the following operations:

[0011] Based on the vehicle-mounted single Beidou positioning requirement, establish a signal transmission connection between the Beidou satellite navigation receiver and Beidou satellites;

[0012] Among them, the Beidou satellite navigation receiver transmits an instruction requesting to establish a signal transmission connection to the Beidou satellite, and the Beidou satellite, based on the instruction requesting to establish a signal transmission connection transmitted by the Beidou satellite navigation receiver, transmits an instruction consenting to establish a signal transmission connection to the Beidou satellite navigation receiver;

[0013] The Beidou satellite navigation receiver receives the instruction consenting to establish a signal transmission connection transmitted by the Beidou satellite, and the Beidou satellite navigation receiver establishes a signal transmission connection with the Beidou satellite based on the instruction consenting to establish a signal transmission connection transmitted by the Beidou satellite;

[0014] Among them, the Beidou satellite sends an electromagnetic wave signal to the ground, and the Beidou satellite navigation receiver installed on the vehicle captures and receives the electromagnetic wave signal sent by the Beidou satellite, and then determines the Beidou satellite signal.

[0015] Preferably, the signal transmission operation quality between the Beidou satellite navigation receiver and Beidou satellites is monitored in real time, and when the signal transmission operation is abnormal, an abnormal alarm is given, including:

[0016] The first signal transmission operation parameters and the second signal transmission operation parameters between the Beidou satellite navigation receiver and Beidou satellites are monitored in real time. Among them, the first signal transmission operation parameters include the strength of each Beidou satellite signal, the signal transmission delay rate, the signal-to-noise ratio, and the number of satellites; the second signal transmission operation parameters include the multipath signal fading amplitude, the multipath delay rate, and the ratio of the strength of the reflected path signal to the direct path signal;

[0017] Use the first signal transmission operation parameters to obtain the first operation evaluation coefficient between each Beidou satellite and the Beidou satellite navigation receiver;

[0018] Among them, the first operation evaluation coefficient corresponding to each Beidou satellite is obtained through the following formula:

[0019] ;

[0020] where R 01Represents the first operation evaluation coefficient corresponding to each Beidou satellite; n represents the number of unit time intervals experienced by the signal transmission between the Beidou satellite navigation receiver and each Beidou satellite, and the unit time is 1 s; S i Represents the Beidou satellite signal strength corresponding to the i-th unit time of each Beidou satellite; SNR i Represents the signal-to-noise ratio corresponding to the i-th unit time of each Beidou satellite; SNR x Represents a preset signal-to-noise ratio reference value; ε is a preset proportionality coefficient, and the value range of the proportionality coefficient is 0.001 - 0.008; S max and S min Represents the maximum and minimum values of the Beidou satellite signal strength that appear in the n unit time intervals corresponding to each Beidou satellite; S b Represents the standard deviation of the Beidou satellite signal strength in n unit time intervals; P tb Represents the standard deviation of the signal transmission delay rate in the n unit time intervals corresponding to each Beidou satellite; P tmax Represents the signal transmission delay rate corresponding to the maximum signal-to-noise ratio that appears in the n unit time intervals corresponding to each Beidou satellite;

[0021] Compare the first operation evaluation coefficient corresponding to each Beidou satellite with a preset first coefficient threshold;

[0022] When the first operation evaluation coefficient corresponding to each Beidou satellite is lower than the preset first coefficient threshold, then retrieve the second signal transmission operation parameters, and use the second signal transmission operation parameters to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite.

[0023] Preferably, when the first operation evaluation coefficient corresponding to each Beidou satellite is lower than the preset first coefficient threshold, then retrieve the second signal transmission operation parameters, and use the second signal transmission operation parameters to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, including:

[0024] When there is any one of the multiple Beidou satellites whose first operation evaluation coefficient is lower than the preset first coefficient threshold, then use the Beidou satellite corresponding to the first operation evaluation coefficient lower than the preset first coefficient threshold as the target satellite;

[0025] Retrieve 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, multipath delay rate, and the ratio of the reflected path signal strength to the direct path signal strength corresponding to the target satellite;

[0026] Use the second signal transmission operation parameters of the target satellite to obtain the second operation evaluation coefficient corresponding to the target satellite;

[0027] Among them, the second operation evaluation coefficient corresponding to the target satellite is obtained through the following formula:

[0028] ;

[0029] Among them, R 02m represents the second operation evaluation coefficient corresponding to the target satellite; D m represents the ratio of the intensity of the reflected path signal to the direct path signal 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 represents 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 represents the change rate of the Beidou satellite signal intensity of the target satellite in n unit times;

[0030] Compare the second operation evaluation coefficient corresponding to the target satellite with a preset second coefficient threshold;

[0031] When the second operation evaluation coefficient corresponding to the target satellite exceeds the preset second coefficient threshold, only risk warnings are given for the target satellite;

[0032] When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite in combination with the second operation evaluation coefficients of other Beidou satellites except the target satellite.

[0033] Preferably, when the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite in combination with the second operation evaluation coefficients of other Beidou satellites except the target satellite, including:

[0034] When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, use other Beidou satellites except the target satellite as observation satellites;

[0035] Extract the second signal transmission operation parameters corresponding to the observation satellites; among them, the second signal transmission operation parameters of the observation satellites include the multipath signal fading amplitude, multipath delay rate, and the ratio of the intensity of the reflected path signal to the direct path signal corresponding to the target satellite;

[0036] Obtain the second operation evaluation coefficient corresponding to the observation satellite by using the second signal transmission operation parameter corresponding to the observation satellite;

[0037] Among them, the second operation evaluation coefficient corresponding to the observation satellite is obtained through the following formula:

[0038] ;

[0039] Among them, R 02g represents the second operation evaluation coefficient corresponding to the observation satellite; D m represents the ratio of the intensity of the reflected path signal to the direct path signal corresponding to the target satellite; D g represents the ratio of the intensity of the reflected path signal to the direct path signal corresponding to the observation satellite; M fg represents the proportional value of the multipath signal fading amplitude corresponding to the observation satellite; M tg represents the multipath delay rate corresponding to the observation satellite; B gb represents the change rate of the Beidou satellite signal intensity of the observation satellite corresponding to n unit times; B mb represents the change rate of the Beidou satellite signal intensity of the target satellite corresponding to n unit times;

[0040] Obtain the comprehensive operation evaluation coefficient by using the second operation evaluation coefficient corresponding to the observation satellite and the second operation evaluation coefficient corresponding to the target satellite;

[0041] Among them, the comprehensive operation evaluation coefficient is obtained through the following formula:

[0042] ;

[0043] Among them, R z represents the comprehensive operation evaluation coefficient; m represents the number of observation 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 the adjustment factor, and the value range of the adjustment factor is 0.27 - 0.82;

[0044] Compare the comprehensive operation evaluation coefficient with the preset comprehensive coefficient threshold;

[0045] When the comprehensive operation evaluation coefficient is lower than the 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 given.

[0046] Preferably, the processor includes:

[0047] A signal processing module, which is used to decode the Beidou satellite signal, determine the Beidou satellite navigation data, and clean and optimize the Beidou satellite navigation data;

[0048] A position calculation module, which is used to calculate the vehicle position information by using the distance-based nearest neighbor algorithm.

[0049] Preferably, the signal processing module includes:

[0050] A signal decoding unit, which is used to decode the Beidou satellite signal;

[0051] Obtain the Beidou satellite signal, extract the PN code from the Beidou satellite signal,

[0052] wherein, the PN code is an encoding method used for randomizing signals in the Beidou satellite system;

[0053] By identifying the PN code, calculate the propagation delay and Doppler frequency shift information of the Beidou satellite signal;

[0054] Based on the PN code and the Beidou satellite signal, calculate the pseudorange and pseudoscale;

[0055] wherein, the pseudorange is the physical distance from the Beidou satellite to the Beidou satellite navigation receiver;

[0056] The pseudoscale is the angle from the Beidou satellite navigation receiver to the direction of the Beidou satellite;

[0057] Based on the pseudorange and pseudoscale, estimate the position and state of the Beidou satellite, determine the Beidou satellite speed, after calculating the position and speed of the Beidou satellite, extract and decode the navigation message of the Beidou satellite;

[0058] wherein, the navigation message includes the timestamp, atomic clock error and service information of the Beidou satellite;

[0059] Based on the position, speed and timestamp of the Beidou satellite, determine the Beidou satellite navigation data.

[0060] Preferably, extracting the PN code from the Beidou satellite signal includes:

[0061] Synchronize the Beidou satellite signal with the reference signal of the Beidou satellite, set a localized PN code sequence on the Beidou satellite navigation receiver, and make it match the PN code sequence of the Beidou satellite;

[0062] Perform depolarization processing on the Beidou satellite signal to eliminate the distortion of the Beidou satellite signal caused by the earth's magnetic field;

[0063] Perform noise reduction processing on the Beidou satellite signal to eliminate the noise and clutter in the Beidou satellite signal;

[0064] Modulate the Beidou satellite signal, remove all frequency modulation components in the Beidou satellite signal except the PN code, and then extract the PN code.

[0065] Preferably, the signal processing module further includes:

[0066] A data optimization unit for cleaning and optimizing the Beidou satellite navigation data;

[0067] Obtain the decoded Beidou satellite navigation data;

[0068] Cleaning and optimizing the decoded Beidou satellite navigation data includes:

[0069] Perform a consistency check on the Beidou satellite navigation data;

[0070] According to the data consistency requirements, check whether the Beidou satellite navigation data contains inconsistent data that is useless for vehicle single Beidou positioning, and remove the inconsistent data in the Beidou satellite navigation data;

[0071] Perform an invalid value and missing value check on the Beidou satellite navigation data;

[0072] 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 single Beidou positioning, and remove the invalid values and missing values in the Beidou satellite navigation data;

[0073] Determine the Beidou satellite navigation data that is useful for vehicle single Beidou positioning.

[0074] Preferably, the position calculation module includes:

[0075] A scheme formulation unit for formulating a vehicle position calculation scheme;

[0076] Obtain the Beidou satellite navigation data that is useful for vehicle single Beidou positioning;

[0077] Analyze the Beidou satellite navigation data that is useful for vehicle single Beidou positioning and formulate a vehicle position calculation scheme;

[0078] A position calculation unit for accurately calculating the vehicle position;

[0079] Obtain the vehicle position calculation scheme;

[0080] Accurately calculate the vehicle position based on the vehicle position calculation scheme.

[0081] Preferably, to accurately calculate the vehicle position, perform the following operations:

[0082] Use the distance-based nearest neighbor algorithm to calculate the vehicle position information;

[0083] For the current vehicle, compare it with all reference stations, calculate the distances between them, and select the vehicle with the minimum sum of distances as the current hypothesized vehicle;

[0084] Based on the position of the current hypothesized vehicle and the Beidou satellite navigation data, use the distance-based nearest neighbor algorithm to update the position of the hypothesized vehicle, and select new candidate vehicles, and loop in turn until the stop condition is met;

[0085] When the stop condition is reached, output the last position of the hypothesized vehicle, which is the actual position of the vehicle, and then calculate the vehicle position information.

[0086] Compared with the prior art, the beneficial effects of the present invention are:

[0087] The present invention receives the signals sent by the Beidou satellites to the ground through a Beidou satellite navigation receiver to determine the Beidou satellite signals, decodes and processes the Beidou satellite signals through a processor to determine the 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 to determine the vehicle position information, and stores the Beidou satellite signals and the vehicle position information through a memory. This 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, and can effectively improve the safety and operation efficiency of the vehicle and enhance the use effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 It is a module architecture diagram of the vehicle-mounted single Beidou positioning terminal system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0089] The following will clearly and completely describe the technical solutions in the embodiments of the present invention 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 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.

[0090] In order to solve the problem that the existing vehicle-mounted positioning terminal has poor positioning reliability, cannot effectively improve the safety and operation efficiency of the vehicle, and results in poor use effect, please refer to Figure 1 , the following technical solutions are provided in this embodiment:

[0091] A vehicle-mounted single Beidou positioning terminal system includes a processor, a Beidou satellite navigation receiver and a memory installed on the vehicle.

[0092] It should be noted that the Beidou satellite navigation receiver receives the signals sent by Beidou satellites to the ground to determine the Beidou satellite signals; the processor processes the Beidou satellite signals to determine the vehicle position information; the memory stores the Beidou satellite signals and the vehicle position information. This 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 vehicles.

[0093] In this embodiment, the Beidou satellite navigation receiver receives the signals sent by Beidou satellites, including:

[0094] Based on the vehicle-mounted single-Beidou positioning requirements, establish a signal transmission connection between the Beidou satellite navigation receiver and the Beidou satellite;

[0095] Among them, the Beidou satellite navigation receiver transmits an instruction requesting to establish a signal transmission connection to the Beidou satellite, and the Beidou satellite establishes a signal transmission connection based on the instruction requesting to establish a signal transmission connection transmitted by the Beidou satellite navigation receiver, and the Beidou satellite transmits an instruction agreeing to establish a signal transmission connection to the Beidou satellite navigation receiver;

[0096] The Beidou satellite navigation receiver receives the instruction agreeing to establish a signal transmission connection transmitted by the Beidou satellite, and the Beidou satellite navigation receiver establishes a signal transmission connection with the Beidou satellite based on the instruction agreeing to establish a signal transmission connection transmitted by the Beidou satellite;

[0097] Among them, the Beidou satellite sends an electromagnetic wave signal to the ground, and the Beidou satellite navigation receiver installed on the vehicle captures and receives the electromagnetic wave signal sent by the Beidou satellite, and then determines the Beidou satellite signal.

[0098] Specifically, the signal transmission operation quality between the Beidou satellite navigation receiver and the Beidou satellite is monitored in real time, and when the signal transmission operation is abnormal, an abnormal alarm is given, including:

[0099] The first signal transmission operation parameters and the second signal transmission operation parameters between the Beidou satellite navigation receiver and the Beidou satellite are monitored in real time. Among them, the first signal transmission operation 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 operation parameters include the multipath signal fading amplitude, the multipath delay rate, and the ratio of the reflected path signal strength to the direct path signal strength;

[0100] Use the first signal transmission operation parameters to obtain the first operation evaluation coefficient between each Beidou satellite and the Beidou satellite navigation receiver;

[0101] Among them, the first operation evaluation coefficient corresponding to each Beidou satellite is obtained through the following formula:

[0102] ;

[0103] Among them, R 01 represents the first operation evaluation coefficient corresponding to each Beidou satellite; n represents the number of unit time intervals experienced by the signal transmission between the Beidou satellite navigation receiver and each Beidou satellite, and the unit time is 1 s; S i represents the Beidou satellite signal strength corresponding to the i-th unit time of each Beidou satellite; SNR i represents the signal-to-noise ratio corresponding to the i-th unit time of each Beidou satellite; SNR x represents a preset signal-to-noise ratio reference value; ε is a preset proportionality coefficient, and the value range of the proportionality coefficient is 0.001 - 0.008; S max and S min represent the maximum and minimum values of the Beidou satellite signal strength that appear in the n unit time intervals corresponding to each Beidou satellite; S b represents the standard deviation of the Beidou satellite signal strength in n unit time intervals; P tb represents the standard deviation of the signal transmission delay rate in the n unit time intervals corresponding to each Beidou satellite; P tmax represents the signal transmission delay rate corresponding to the maximum signal-to-noise ratio that appears in the n unit time intervals corresponding to each Beidou satellite;

[0104] Compare the first operation evaluation coefficient corresponding to each Beidou satellite with a preset first coefficient threshold;

[0105] 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.

[0106] The technical effects of the above technical solution are as follows: By real-time monitoring the first signal transmission operation parameters (such as signal strength, signal transmission delay rate, signal-to-noise ratio, and number of satellites) between the Beidou satellite navigation receiver and Beidou satellites and the second signal transmission operation parameters (such as multipath signal fading amplitude, multipath delay rate, and ratio of reflected path signal strength to direct path signal strength), the operation status of signal transmission can be comprehensively and accurately grasped. The first operation evaluation coefficient calculated using the first signal transmission operation parameters can quantitatively evaluate the signal transmission quality between each Beidou satellite and the receiver, providing accurate data support for subsequent anomaly judgment. By comparing the first operation evaluation coefficient with a preset first coefficient threshold, when the evaluation coefficient is lower than the threshold, the anomaly alarm mechanism can be quickly triggered to achieve a rapid response to signal transmission anomalies. After confirming that there are anomalies in the first signal transmission operation parameters, the second signal transmission operation parameters are further retrieved for determination, increasing the hierarchy and accuracy of anomaly judgment and reducing 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 consider the influence of time variation, and are statistically analyzed through multiple data points within a unit time (such as 1 second), improving the stability and reliability of the evaluation results. The value range of the proportionality coefficient ε (0.001 - 0.008) provides a certain degree of flexibility for the algorithm, which can be adjusted according to actual situations 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 operation status of signal transmission, improving the robustness of the system. This technical solution can real-time monitor and quickly respond to signal transmission anomalies, helping to take timely measures to avoid or reduce navigation positioning errors or failures caused by signal transmission problems. By quantitatively evaluating signal transmission quality, it provides strong data support for system maintenance and optimization, helping to improve the overall performance and user experience of the Beidou satellite navigation system.

[0107] In summary, this technical solution shows technical effects such as real-time monitoring, precise evaluation, sensitivity and accuracy of anomaly warning, adaptability and robustness, as well as efficiency and practicality in performance indicators, which is of great significance for improving the reliability and stability of the Beidou satellite navigation system.

[0108] 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 parameters are retrieved, and the second signal transmission operation parameters are used to determine whether there are anomalies in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite, including:

[0109] When any one of the multiple Beidou satellites has a first operation evaluation coefficient lower than a preset first coefficient threshold, the Beidou satellite corresponding to the first operation evaluation coefficient lower than the preset first coefficient threshold is used as the target satellite;

[0110] Retrieve 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, multipath delay rate, and the ratio of the reflected path signal intensity to the direct path signal intensity corresponding to the target satellite;

[0111] Obtain the second operation evaluation coefficient corresponding to the target satellite by using the second signal transmission operation parameters of the target satellite;

[0112] Among them, the second operation evaluation coefficient corresponding to the target satellite is obtained through the following formula:

[0113] ;

[0114] Among them, R 02m represents the second operation evaluation coefficient corresponding to the target satellite; D m represents the ratio of the reflected path signal intensity to the direct path signal intensity corresponding to the target satellite; R m01 represents the first operation evaluation coefficient corresponding to the target satellite; R y represents the preset first coefficient threshold; β represents the adjustment coefficient, and the value range of the adjustment coefficient is 0.38 - 1.17; M fm represents 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 represents the Beidou satellite signal intensity change rate corresponding to the target satellite in n unit times;

[0115] Compare the second operation evaluation coefficient corresponding to the target satellite with a preset second coefficient threshold;

[0116] When the second operation evaluation coefficient corresponding to the target satellite exceeds the preset second coefficient threshold, only risk warnings are given for the target satellite;

[0117] When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, it is determined whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite by combining the second operation evaluation coefficients of other Beidou satellites except the target satellite.

[0118] The technical effects of the above technical solution are as follows: By first monitoring the first signal transmission operation parameters and calculating the first operation evaluation coefficient, it is possible to preliminarily screen out the Beidou satellites (i.e., target satellites) that may be abnormal. This step effectively reduces unnecessary comprehensive inspections and improves the monitoring efficiency. When the first operation evaluation coefficient is lower than the preset threshold, the second signal transmission operation parameters of the target satellite are then 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, multipath delay rate, ratio of the reflected path signal intensity to the direct path signal intensity, and signal intensity 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, the 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 degree of flexibility for the algorithm, which can be adjusted according to the actual application scenarios and requirements to adapt to different signal transmission environments and conditions. This technical solution not only considers the abnormal situation of the target satellite but also combines the second operation evaluation coefficients of other Beidou satellites for comprehensive determination, improving the overall robustness and reliability of the system. Through the methods of hierarchical monitoring and comprehensive evaluation, this technical solution realizes the real-time monitoring and abnormal warning of the signal transmission quality between the Beidou satellite navigation receiver and the Beidou satellite, helping to timely discover and handle potential signal transmission problems. At the same time, this technical solution also has a certain degree of practicality and can be applied to various scenarios requiring high-precision navigation and positioning, providing strong guarantee for users' navigation and positioning needs.

[0119] In summary, this technical solution shows technical effects such as hierarchical monitoring and precise abnormal positioning, comprehensive evaluation and risk warning, flexibility and robustness, as well as efficiency and practicality in performance indicators, which is of great significance for improving the stability and reliability of the Beidou satellite navigation system.

[0120] Specifically, when the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellite is determined for abnormality by combining the second operation evaluation coefficients of other Beidou satellites except the target satellite, including:

[0121] 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;

[0122] Extract the second signal transmission and operation parameters corresponding to the observation satellite; wherein, the second signal transmission and operation parameters of the observation satellite include the multipath signal fading amplitude, multipath delay rate corresponding to the target satellite, and the ratio of the intensity of the reflected path signal to the direct path signal;

[0123] Obtain the second operation evaluation coefficient corresponding to the observation satellite by using the second signal transmission and operation parameters corresponding to the observation satellite;

[0124] Wherein, the second operation evaluation coefficient corresponding to the observation satellite is obtained through the following formula:

[0125] ;

[0126] Wherein, R 02g represents the second operation evaluation coefficient corresponding to the observation satellite; D m represents the ratio of the intensity of the reflected path signal to the direct path signal corresponding to the target satellite; D g represents the ratio of the intensity of the reflected path signal to the direct path signal corresponding to the observation satellite; M fg represents the proportional value of the multipath signal fading amplitude corresponding to the observation satellite; M tg represents the multipath delay rate corresponding to the observation satellite; B gb represents the change rate of the Beidou satellite signal intensity corresponding to the observation satellite in n unit times; B mb represents the change rate of the Beidou satellite signal intensity corresponding to the target satellite in n unit times;

[0127] Obtain the comprehensive operation evaluation coefficient by using the second operation evaluation coefficient corresponding to the observation satellite and the second operation evaluation coefficient corresponding to the target satellite;

[0128] Wherein, the comprehensive operation evaluation coefficient is obtained through the following formula:

[0129] ;

[0130] Wherein, R z represents the comprehensive operation evaluation coefficient; m represents the number of observation 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 the adjustment factor, and the value range of the adjustment factor is 0.27 - 0.82;

[0131] Compare the comprehensive operation evaluation coefficient with the preset comprehensive coefficient threshold;

[0132] When the comprehensive operation evaluation coefficient is lower than the 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 given.

[0133] The technical effects of the above technical solution are as follows: This technical solution not only focuses on the second operation evaluation coefficient of the target satellite (i.e., the satellite that may be abnormally judged initially), but also considers the second operation evaluation coefficients of other observed satellites, realizing the 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 observed satellites are combined, providing 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 intensity, the proportional value of the multipath signal fading amplitude, the multipath delay rate, and the change rate of the Beidou satellite signal intensity, etc. These factors together reflect the quality of the 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. This technical solution determines the abnormality of the signal transmission by comprehensively evaluating the results of multiple satellites, enhancing the robustness of the system. Even if the evaluation results of individual satellites are interfered or have errors, it will not have a great impact on the overall judgment result. At the same time, by adjusting the preset coefficient threshold, this technical solution can adapt to different application scenarios and signal transmission environments, improving the flexibility and adaptability of the system. This technical solution realizes the real-time monitoring and abnormality determination of the signal transmission quality, can discover potential problems in the first time, and helps to take measures in time to avoid or reduce the impact of signal transmission abnormalities on the navigation and positioning accuracy. Through the method of hierarchical monitoring and comprehensive evaluation, this technical solution improves the monitoring efficiency, reduces unnecessary comprehensive inspections, and reduces the consumption of system resources.

[0134] In summary, this technical solution shows technical effects such as comprehensive monitoring and comprehensive evaluation, accuracy of abnormality determination, robustness, efficiency, real-time performance, and practicability in performance indicators, which is of great significance for improving the overall performance and user experience of the Beidou satellite navigation system.

[0135] In this embodiment, the processor includes: a signal processing module and a position calculation module.

[0136] It should be noted that the signal processing module decodes the Beidou satellite signal to determine the Beidou satellite navigation data and cleans and optimizes the Beidou satellite navigation data; the position calculation module calculates the vehicle position information using the distance-based nearest neighbor algorithm, which has high accuracy and reliability.

[0137] In this embodiment, the signal processing module includes:

[0138] A signal decoding unit for decoding the Beidou satellite signal;

[0139] It should be noted that decoding is a process of restoring digital codes to their represented content or converting electrical pulse signals, optical signals, radio waves, etc. into the information, data, etc. they represent using specific methods; decoding is the process by which the recipient restores the received symbols or codes into information, corresponding 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 forms used in the communication network and the transmission device are different, signal form conversion must be performed. Generally, the signal form conversion performed at the sender is called encoding, and the signal form conversion performed at the receiver is called decoding.

[0140] Specifically, obtain the Beidou satellite signal and extract the PN code from the Beidou satellite signal.

[0141] Among them, the PN code is an encoding method used to randomize signals in the Beidou satellite system.

[0142] It should be noted that the PN code is a coding sequence composed of 0s and 1s with autocorrelation properties similar to white noise. Among them, the Beidou satellite transmitter and the Beidou satellite navigation receiver adopt high-precision and high-stability clock frequency sources to ensure the stability of frequency and phase. However, in actual applications, there are many unpredictable uncertain factors, such as unstable transceiver clocks, uncertain transmission times, channel transmission delays, and interference. Especially in mobile communications, these uncertain factors are random and cannot be compensated in advance, and can only be eliminated through a synchronization system. Therefore, in CDMA spread-spectrum communication, the synchronization system is essential.

[0143] By identifying the PN code, calculate the propagation delay and Doppler frequency shift information of the Beidou satellite signal.

[0144] It should be noted that the Doppler frequency shift refers to the change in phase and frequency caused by the difference in propagation path when the mobile station moves at a constant speed in a certain direction. Usually, this change is called the Doppler frequency shift; it reveals the law of change of the properties of waves during motion. When the motion is in front of the wave source, the wave is compressed, the wavelength becomes shorter, and the frequency becomes higher; when the motion is behind the wave source, the opposite effect occurs, the wavelength becomes longer, and the frequency becomes lower.

[0145] Based on the PN code and the Beidou satellite signal, calculate the pseudorange and pseudoscale.

[0146] Among them, the pseudorange is the physical distance from the Beidou satellite to the Beidou satellite navigation receiver.

[0147] The pseudo-scale is the angle from the Beidou satellite navigation receiver to the direction of the Beidou satellite;

[0148] Based on the pseudo-range and pseudo-scale, estimate the position and status of the Beidou satellite, determine the speed of the Beidou satellite. After calculating the position and speed of the Beidou satellite, extract and decode the navigation message of the Beidou satellite;

[0149] Among them, the navigation message includes the timestamp, atomic clock error and service information of the Beidou satellite;

[0150] Based on the position, speed and timestamp of the Beidou satellite, determine the Beidou satellite navigation data.

[0151] In this embodiment, extracting the PN code from the Beidou satellite signal includes:

[0152] Synchronize the Beidou satellite signal with the reference signal of the Beidou satellite, set a localized PN code sequence on the Beidou satellite navigation receiver, and make it match the PN code sequence of the Beidou satellite;

[0153] Perform depolarization processing on the Beidou satellite signal to eliminate the distortion of the Beidou satellite signal caused by the earth's magnetic field;

[0154] Perform noise reduction processing on the Beidou satellite signal to eliminate the noise and clutter in the Beidou satellite signal;

[0155] Perform modulation processing on the Beidou satellite signal to remove all frequency modulation components except the PN code in the Beidou satellite signal, and then extract the PN code.

[0156] In this embodiment, the process of calculating the pseudo-range and pseudo-scale based on the PN code and the Beidou satellite signal is usually called "Pseudo Distance Location (PDL)", which is one of the key technologies of the Global Navigation Satellite System. The following is the calculation method of the pseudo-distance and pseudo-scale:

[0157] 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 pseudo-range (PR) can be obtained;

[0158] Then, the pseudo-scale (PS) can be calculated using the pseudo-range (PR). The pseudo-scale is a linear transformation of the pseudo-range, which provides the exact position of the measurement point. Among them, the calculation formula of the pseudo-scale is:

[0159] PS = 2 * (PR^2 - 1) / ((PR + 1)^2 - 1)

[0160] When calculating the pseudo-scale, the Doppler effect needs to be considered. The Doppler effect is the change in signal frequency due to the relative motion between the receiver and the satellite. To avoid the influence of the Doppler effect, appropriate corrections need to be made to the pseudo-range. A commonly used correction method is to use the Doppler frequency shift model (PMM) of the pseudo-range; the Doppler frequency shift model assumes that the frequency transmitted by the satellite is constant near the receiver. Therefore, the pseudo-range (PR) can be converted into the pseudo-scale (PS) using the Doppler frequency shift model of the pseudo-range. The calculation formula for the pseudo-scale (PS) is:

[0161] PS_corrected = PS / (1 + 2 *V_OR / c)

[0162] where V_OR is the average relative velocity between the receiver and the satellite, c is the speed of light (about 3*10^8 m / s), and PS_corrected is the pseudo-scale after Doppler correction;

[0163] Specifically, the calculation of the pseudo-range and the 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.

[0164] In this embodiment, the signal processing module further includes:

[0165] A data optimization unit for cleaning and optimizing the Beidou satellite navigation data;

[0166] Obtain the decoded Beidou satellite navigation data;

[0167] The cleaning and optimization of the decoded Beidou satellite navigation data includes:

[0168] Perform consistency checks on the Beidou satellite navigation data;

[0169] 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 from the Beidou satellite navigation data;

[0170] Perform invalid value and missing value checks on the Beidou satellite navigation data;

[0171] 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 from the Beidou satellite navigation data;

[0172] Determine the Beidou satellite navigation data that is useful for vehicle-mounted single Beidou positioning.

[0173] It should be noted that by cleaning and optimizing the Beidou satellite navigation data, the inconsistent data, invalid values, and missing values in the Beidou satellite navigation data that are useless for vehicle-mounted single Beidou positioning can be removed, and the Beidou satellite navigation data useful for vehicle-mounted single Beidou positioning can be determined. This can improve the calculation accuracy and calculation efficiency of the subsequent Beidou satellite navigation data, making the vehicle-mounted single Beidou positioning terminal system have high accuracy and reliability, and can effectively improve the safety and operation efficiency of the vehicle.

[0174] In this embodiment, the position calculation module includes:

[0175] A scheme formulation unit for formulating a vehicle position calculation scheme;

[0176] Obtain the Beidou satellite navigation data useful for vehicle-mounted single Beidou positioning;

[0177] Analyze the Beidou satellite navigation data useful for vehicle-mounted single Beidou positioning and formulate a vehicle position calculation scheme;

[0178] A position calculation unit for accurately calculating the vehicle position;

[0179] Obtain the vehicle position calculation scheme;

[0180] Accurately calculate the vehicle position based on the vehicle position calculation scheme.

[0181] Specifically, to accurately calculate the vehicle position, the following operations are performed:

[0182] Use the distance-based nearest neighbor algorithm to calculate the vehicle position information;

[0183] For the current vehicle, compare it with all reference stations, calculate the distances between them, and select the vehicle with the smallest sum of distances as the current hypothesized vehicle;

[0184] According to the position of the current hypothesized vehicle and the Beidou satellite navigation data, use the distance-based nearest neighbor algorithm to update the position of the hypothesized vehicle, and select a new candidate vehicle, and loop in turn until the stop condition is met;

[0185] When the stop condition is reached, output the last position of the hypothesized vehicle, that is, the actual position of the vehicle, and then calculate the vehicle position information.

[0186] It should be noted that by decoding and processing the Beidou satellite signals through a processor to determine the Beidou satellite navigation data and cleaning and optimizing the Beidou satellite navigation data, the calculation accuracy and calculation efficiency of the subsequent Beidou satellite navigation data can be improved. By analyzing the Beidou satellite navigation data, a vehicle position calculation scheme is formulated, and based on the vehicle position calculation scheme, the vehicle position is accurately calculated to determine the vehicle position information. By storing the Beidou satellite signals and the vehicle position information in a memory, the on-vehicle single Beidou positioning terminal system can be made 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 and enhance the use effect.

[0187] It should be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0188] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and 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 a vehicle, characterized in that, The Beidou satellite navigation receiver is used to receive the signals sent by Beidou satellites to the ground and determine the Beidou satellite signals; The processor is used to process the Beidou satellite signals and determine the vehicle position information; The memory is used to store the Beidou satellite signals and the vehicle position information; The Beidou satellite navigation receiver receives the signals sent by Beidou satellites and performs the following operations: Based on the on-vehicle single Beidou positioning requirement, establish a signal transmission connection between the Beidou satellite navigation receiver and the Beidou satellites; Among them, the Beidou satellite navigation receiver transmits an instruction requesting to establish a signal transmission connection to the Beidou satellites, and the Beidou satellites, based on the instruction requesting to establish a signal transmission connection transmitted by the Beidou satellite navigation receiver, transmit an instruction consenting to establish a signal transmission connection to the Beidou satellite navigation receiver; When the Beidou satellite navigation receiver receives the instruction consenting to establish a signal transmission connection transmitted by the Beidou satellites, the Beidou satellite navigation receiver establishes a signal transmission connection with the Beidou satellites based on the instruction consenting to establish a signal transmission connection transmitted by the Beidou satellites; Among them, the 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 satellites, and then determines the Beidou satellite signals; Real-time monitor the signal transmission operation quality between the Beidou satellite navigation receiver and the Beidou satellites, and when the signal transmission operation is abnormal, perform an abnormal alarm, including: Real-time monitor the first signal transmission operation parameters and the second signal transmission operation parameters between the Beidou satellite navigation receiver and the Beidou satellites. Among them, the first signal transmission operation 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 operation parameters include the multipath signal fading amplitude, the multipath delay rate, and the ratio of the reflected path signal strength to the direct path signal strength; Use the first signal transmission operation parameters to obtain the first operation evaluation coefficient between each Beidou satellite and the Beidou satellite navigation receiver; Among them, the first operation evaluation coefficient corresponding to each Beidou satellite is obtained through the following formula: ； Among them, R 01 represents the first operation evaluation coefficient corresponding to each Beidou satellite; n represents the number of unit time intervals experienced by the signal transmission between the Beidou satellite navigation receiver and each Beidou satellite, and the unit time is 1 s; S i represents the Beidou satellite signal strength corresponding to the i-th unit time of each Beidou satellite; SNR i represents the signal-to-noise ratio corresponding to the i-th unit time of each Beidou satellite; SNR x represents the preset signal-to-noise ratio reference value; ε is a preset proportionality coefficient, and the value range of the proportionality coefficient is 0.001 - 0.008; S max and S min represent the maximum and minimum values of the Beidou satellite signal strength that occur in the n unit time intervals corresponding to each Beidou satellite; S b represents the standard deviation of the Beidou satellite signal strength in n unit time intervals; P tb represents the standard deviation of the signal transmission delay rate in the n unit time intervals corresponding to each Beidou satellite; P tmax represents the signal transmission delay rate corresponding to the maximum signal-to-noise ratio that occurs in the n unit time intervals corresponding to 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, then retrieve the second signal transmission operation parameters, and use the second signal transmission operation parameters to determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellites, including: When there is any Beidou satellite among multiple Beidou satellites whose first operation evaluation coefficient is lower than the preset first coefficient threshold, then use the Beidou satellite corresponding to the first operation evaluation coefficient lower than the preset first coefficient threshold as the target satellite; Retrieve the second signal transmission operation parameters of the target satellite; among them, 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 strength to the direct path signal strength corresponding to the target satellite; Use the second signal transmission operation parameters of the target satellite to obtain the second operation evaluation coefficient corresponding to the target satellite; Among them, the second operation evaluation coefficient corresponding to the target satellite is obtained through the following formula: ； Among them, R 02m represents the second operation evaluation coefficient corresponding to the target satellite; D m represents the ratio of the intensity of the reflected path signal to the direct path signal 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 a regulation coefficient, and the value range of the regulation coefficient is 0.38 - 1.17; M fm represents 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 represents the change rate of the Beidou satellite signal intensity of the target satellite in n unit time intervals; Compare the 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 the preset second coefficient threshold, only risk warnings are issued for the target satellite; When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, determine whether there is an abnormality in the signal transmission operation between the Beidou satellite navigation receiver and the Beidou satellites by combining the second operation evaluation coefficients of other Beidou satellites except the target satellite, including: When the second operation evaluation coefficient corresponding to the target satellite does not exceed the preset second coefficient threshold, use other Beidou satellites except the target satellite as observation satellites; Extract the second signal transmission operation parameters corresponding to the observation satellites; among them, the second signal transmission operation parameters of the observation satellites include the multipath signal fading amplitude, multipath delay rate, and the ratio of the reflected path signal intensity to the direct path signal intensity corresponding to the target satellite; Use the second signal transmission operation parameters corresponding to the observation satellites to obtain the second operation evaluation coefficient corresponding to the observation satellites; Among them, the second operation evaluation coefficient corresponding to the observation satellites is obtained through the following formula: ； Among them, R 02g represents the second operation evaluation coefficient corresponding to the observation satellite; D m represents the ratio of the intensity of the reflected path signal to the direct path signal corresponding to the target satellite; D g represents the ratio of the intensity of the reflected path signal to the direct path signal corresponding to the observation satellite; M fg represents the proportional value of the multipath signal fading amplitude corresponding to the observation satellite; M tg represents the multipath delay rate corresponding to the observation satellite; B gb represents the change rate of the Beidou satellite signal intensity corresponding to the observation satellite in n unit time; B mb represents the change rate of the Beidou satellite signal intensity corresponding to the target satellite in n unit time; Use the second operation evaluation coefficient corresponding to the observation satellites and the second operation evaluation coefficient corresponding to the target satellite to obtain a comprehensive operation evaluation coefficient; Among them, the comprehensive operation evaluation coefficient is obtained through the following formula: ； Among them, R z represents the comprehensive operation evaluation coefficient; m represents the number of observation 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 a regulation factor, and the value range of the regulation factor is 0.27 - 0.82; Compare the comprehensive operation evaluation coefficient with a preset comprehensive coefficient threshold; When the comprehensive operation evaluation coefficient is lower than the 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 satellites, and an abnormality alarm is issued.

2. The vehicle-mounted single Beidou positioning terminal system according to claim 1, characterized in that, The processor includes: A signal processing module for decoding Beidou satellite signals, determining Beidou satellite navigation data, and cleaning and optimizing the Beidou satellite navigation data; A position calculation module for calculating vehicle position information using a distance-based nearest neighbor algorithm.

3. The vehicle-mounted single Beidou positioning terminal system according to claim 2, wherein The signal processing module includes: A signal decoding unit for decoding Beidou satellite signals; Obtain Beidou satellite signals and extract PN codes from the Beidou satellite signals; Among them, the PN code is an encoding method used to randomize signals in the Beidou satellite system; By identifying the PN code, calculate the propagation delay and Doppler frequency shift information of the Beidou satellite signals; Based on the PN code and the Beidou satellite signals, calculate the pseudorange and pseudoscale; Among them, the pseudorange is the physical distance from the Beidou satellite to the Beidou satellite navigation receiver; The pseudoscale is the angle from the Beidou satellite navigation receiver to the direction of the Beidou satellite; Based on the pseudorange and pseudoscale, estimate the position and state of the Beidou satellite, determine the Beidou satellite speed, calculate the position and speed of the Beidou satellite, and then extract and decode the navigation message of the Beidou satellite; Among them, the navigation message includes the timestamp, atomic clock error, and service information of the Beidou satellite; Based on the position, speed, and timestamp of the Beidou satellite, determine the Beidou satellite navigation data.

4. The vehicle-mounted single Beidou positioning terminal system according to claim 3, characterized in that, Extracting the PN code from the Beidou satellite signals 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.

5. The vehicle-mounted single Beidou positioning terminal system according to claim 4, 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.

6. The vehicle-mounted single Beidou positioning terminal system according to claim 5, wherein, 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.

7. The vehicle-mounted single Beidou positioning terminal system according to claim 6, 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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