High-precision positioning method based on Beidou satellite and 5G-Mesh

Abstract

The present invention discloses a high-precision positioning method based on the joint use of Beidou satellites and 5G-Mesh, which relates to the field of satellite positioning technology, including: real-time reception of Beidou satellite navigation signals and 5G-Mesh network communication signals; real-time monitoring of topological changes in the 5G-Mesh network, and dynamic adjustment of the connection relationship between nodes based on network performance indicators; a receiver performs pseudo-range measurement on the signals of visible satellites; demodulates the navigation message from the received satellite signal, and uses a satellite orbit calculation model to calculate the precise position of each satellite at the current moment; constructs a signal strength fingerprint database; outputs a reference position with the highest similarity to the current signal strength characteristics to perform error modeling on the Beidou satellite signal and the 5G-Mesh network signal; and uses a weighted fusion algorithm to fuse the two types of position information. By integrating the technical advantages of the two positioning technologies, positioning accuracy and reliability are improved, meeting the demand for high-precision positioning in complex scenarios.

Description

Technical Field

[0001] The present invention relates to the field of satellite positioning technology, and specifically to a high-precision positioning method based on the combination of Beidou satellites and 5G-Mesh. Background Art

[0002] In the field of intelligent transportation, autonomous vehicles require real-time and accurate knowledge of their location on the road to ensure safe and efficient driving, avoid collisions, and comply with traffic regulations. In intelligent logistics and transportation, freight transport vehicles require precise positioning information to optimize route planning, improve transportation efficiency, and ensure that goods are delivered to their destinations on time and accurately. In the field of industrial automation, robots and automated equipment within factories require high-precision positioning to ensure precise operation and collaborative work. In the construction of smart cities, urban infrastructure management and public safety monitoring also rely on high-precision positioning technology.

[0003] However, existing single-site positioning technologies often struggle to meet the high-precision positioning requirements in these complex scenarios. Traditional satellite positioning technologies (such as Beidou satellite positioning) can provide high positioning accuracy in open environments. However, in complex environments like urban canyons and indoors, positioning accuracy can drop significantly due to factors such as signal obstruction and multipath effects. While wireless communication network-based positioning technologies (such as 5G-Mesh network positioning) can somewhat compensate for the shortcomings of satellite positioning in complex environments, they also suffer from limited positioning accuracy when used alone and are significantly affected by network topology and performance. Summary of the Invention

[0004] In order to solve the above technical problems, a high-precision positioning method based on Beidou satellite and 5G-Mesh is provided. This technical solution solves the problems raised in the above background technology.

[0005] In order to achieve the above objects, the technical solution adopted by the present invention is:

[0006] High-precision positioning method based on BeiDou satellite and 5G-Mesh, including:

[0007] The terminal device has a built-in Beidou and 5G-Mesh signal fusion receiving module, which receives the navigation signals of Beidou satellites and the communication signals of the 5G-Mesh network in real time;

[0008] By monitoring the topology changes of the 5G-Mesh network in real time and combining network performance indicators such as signal strength and transmission delay, the connection relationship between nodes is dynamically adjusted;

[0009] The receiver performs pseudo-range measurements on the signals of visible satellites to obtain at least one set of pseudo-range observation values ​​and observes the carrier phase;

[0010] Demodulate the navigation message from the received satellite signal and calculate the precise position of each satellite at the current moment using the satellite orbit calculation model. The navigation message includes the satellite's orbit parameters and clock correction parameters.

[0011] At at least one reference location, measure the 5G-Mesh signal strength and take the average value to build a signal strength fingerprint database, and measure the arrival time of the signal from the Mesh node to the terminal device;

[0012] When the terminal device is in the positioning state, it measures the signal strength of the current position in real time and matches it with the feature vector in the fingerprint database, and outputs the reference position with the highest similarity to the current signal strength feature as the terminal's position estimate;

[0013] Error modeling is performed on BeiDou satellite signals based on ionospheric delay, tropospheric delay, satellite clock error, and receiver clock error. Error modeling is performed on 5G-Mesh network signals based on multipath effects, signal obstruction, and node clock error.

[0014] The weighted fusion algorithm is used to fuse the two types of position information, and the corresponding weight is assigned to each position information according to the results of error modeling.

[0015] Preferably, the demodulating the navigation message from the received satellite signal and calculating the precise position of each satellite at the current moment using a satellite orbit calculation model specifically includes:

[0016] Identify the subframe start mark of the navigation message, determine the message structure, integrate and judge each data bit, and recover the binary message;

[0017] Parse the message content and extract the satellite's orbital parameters and clock correction parameters;

[0018] Calculate the root of the ratio of the Earth's gravitational constant to the cube of the satellite's orbital semi-major axis, and output it as the satellite's average angular velocity;

[0019] Calculate the product of the average angular velocity and the difference between the current time and the message reference time, and output the sum of the average angular velocity and the initial position of the satellite as the mean anomaly angle;

[0020] Based on Kepler's equation, the value of the eccentric anomaly is solved according to the mean anomaly;

[0021] The true anomaly formula and the current orbital coordinate formula are used to calculate the true anomaly of the satellite and the coordinates of the current satellite in the orbital plane.

[0022] Preferably, when the terminal device is in a positioning state, the signal strength of the current position is measured in real time, matched with the feature vector in the fingerprint database, and the reference position with the highest similarity to the current signal strength feature is output as the terminal position estimation, which specifically includes:

[0023] Compare the current signal strength list with each record in the fingerprint library one by one and calculate the degree of difference between the two;

[0024] Different weights are assigned to the signal strength of different nodes, with the master node having a higher weight;

[0025] The instantaneous speed of BeiDou is calculated through the continuous satellite positioning results, and the displacement change of the continuous fingerprint matching results is used to estimate the 5G-Mesh assisted speed;

[0026] Based on the fusion rule, the comprehensive mobile speed of the terminal device is calculated as the sum of 0.7 times the instantaneous speed of Beidou and 0.3 times the auxiliary speed of 5G-Mesh;

[0027] Determine whether the terminal's comprehensive moving speed is higher than three meters per second. If so, select the five records with the smallest differences as candidate locations. If not, select the three records with the smallest differences as candidate locations.

[0028] The coordinates of the candidate positions are averaged to obtain the final positioning result.

[0029] Preferably, the error modeling of Beidou satellite signals based on ionospheric delay, tropospheric delay, satellite clock error and receiver clock error, and the error modeling of 5G-Mesh network signals based on multipath effect, signal shielding and node clock error specifically include:

[0030] For dual-frequency receivers, the error caused by ionospheric delay is eliminated by using the relationship that ionospheric delay is inversely proportional to the square of the carrier frequency;

[0031] Based on the Sastamonen model, the error caused by tropospheric delay is calculated according to local temperature, pressure and relative humidity;

[0032] The satellite clock error is monitored in real time by ground monitoring stations, and the correction parameters are broadcast to users through navigation messages. Users use the correction parameters to correct the satellite clock error.

[0033] In the positioning solution, the receiver clock error is treated as an unknown number and solved together with the position parameters. The differential positioning technology is used to eliminate the receiver clock error through the clock error observation value between the reference station and the user station.

[0034] Adopt channel modeling technology to simulate the propagation path and attenuation characteristics of signals in complex environments, thereby eliminating errors caused by multipath effects;

[0035] Through field testing and simulation analysis, we can determine the signal blocking area and degree, and optimize the node layout in network planning.

[0036] The signal blocking factor is taken into account in the positioning algorithm, and the signal in the blocked area is weighted to eliminate the error caused by signal blocking.

[0037] The time synchronization protocol is used to achieve clock synchronization of Mesh network nodes. During the positioning process, the node clock error is monitored in real time and corrected through algorithms.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] It greatly enhances the reliability of the positioning system, ensures that positioning services can be provided continuously and stably in various complex environments, improves the system's fault tolerance and robustness, and is of great significance for ensuring the safe operation of key applications. It has strong adaptability to different environments, whether it is densely populated urban areas, indoor environments or remote areas, and can flexibly adjust positioning strategies according to local environmental characteristics and signal conditions to achieve effective positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a flow chart of the high-precision positioning method based on Beidou satellite and 5G-Mesh combined with the present invention;

[0041] Figure 2 This is a flow chart of a method for dynamically adjusting the connection relationship between nodes according to the present invention;

[0042] Figure 3 This is a flow chart of a method for measuring pseudoranges of visible satellite signals by a receiver of the present invention;

[0043] Figure 4 This is a flow chart of a method for calculating the precise position of each satellite at the current moment using a satellite orbit calculation model according to the present invention;

[0044] Figure 5 This is a flow chart of the method for constructing a signal strength fingerprint database of the present invention;

[0045] Figure 6 This is a flow chart of the method for matching feature vectors in a fingerprint database according to the present invention;

[0046] Figure 7 This is a flow chart of the error modeling method for Beidou satellite signals and 5G-Mesh network signals of the present invention. DETAILED DESCRIPTION

[0047] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0048] Reference Figure 1 As shown in the figure, the high-precision positioning method based on BeiDou satellite and 5G-Mesh joint includes:

[0049] The terminal device has a built-in Beidou and 5G-Mesh signal fusion receiving module, which receives the navigation signals of Beidou satellites and the communication signals of the 5G-Mesh network in real time;

[0050] By monitoring the topology changes of the 5G-Mesh network in real time and combining network performance indicators such as signal strength and transmission delay, the connection relationship between nodes is dynamically adjusted;

[0051] The receiver performs pseudo-range measurements on the signals of visible satellites to obtain at least one set of pseudo-range observation values ​​and observes the carrier phase;

[0052] Demodulate the navigation message from the received satellite signal and calculate the precise position of each satellite at the current moment using the satellite orbit calculation model. The navigation message includes the satellite's orbit parameters and clock correction parameters.

[0053] At at least one reference location, measure the 5G-Mesh signal strength and take the average value to build a signal strength fingerprint database, and measure the arrival time of the signal from the Mesh node to the terminal device;

[0054] When the terminal device is in the positioning state, it measures the signal strength of the current position in real time and matches it with the feature vector in the fingerprint database, and outputs the reference position with the highest similarity to the current signal strength feature as the terminal's position estimate;

[0055] Error modeling is performed on BeiDou satellite signals based on ionospheric delay, tropospheric delay, satellite clock error, and receiver clock error. Error modeling is performed on 5G-Mesh network signals based on multipath effects, signal obstruction, and node clock error.

[0056] The weighted fusion algorithm is used to fuse the two types of position information, and the corresponding weight is assigned to each position information according to the results of error modeling.

[0057] Reference Figure 2 As shown in the figure, by real-time monitoring of the topology changes of the 5G-Mesh network and combining it with network performance indicators, the connection relationship between nodes is dynamically adjusted, specifically including:

[0058] Use the network discovery protocol to regularly scan and identify each node in the 5G-Mesh network and its connection status, and record each node's ID, IP address, connection port, and neighbor node list information;

[0059] Based on the node discovery results, a topology diagram of the 5G-Mesh network is constructed. In the diagram, nodes are recorded as devices in the network, and edges are recorded as the connection relationships between devices.

[0060] Deploy performance monitoring agents on each node to collect and report network performance indicator data;

[0061] Use time series analysis to process the collected network performance indicator data and predict the load of each node and connection;

[0062] Combine the current topology with load forecast results to analyze bottlenecks and overloaded nodes in the network, evaluate the performance of each connection path, and determine which connections need to be adjusted.

[0063] Based on topology analysis and load forecast results, formulate connection adjustment strategies, increase or decrease connections, change connection paths, and adjust node power.

[0064] Modules that support network discovery protocols are deployed in the 5G-Mesh network. These modules regularly broadcast discovery requests and listen to responses in the network to identify all active nodes. When responding to a discovery request, each node must provide its unique ID, IP address, connection port, and current neighbor node list. This information will be centrally stored in the network's central controller or distributed database for subsequent processing.

[0065] Reference Figure 3 As shown, the receiver performs pseudo-range measurement on the signals of visible satellites to obtain at least one set of pseudo-range observation values, and observes the carrier phase, specifically including:

[0066] The receiver searches for visible satellite signals by scanning the frequency band and identifying the satellite's pseudo-random noise code. Once the signal is successfully captured, the receiver locks onto the signal and enters the tracking phase.

[0067] The receiver generates a local replica code synchronized with the satellite signal and adjusts the phase and frequency of the local code to align it with the received satellite signal.

[0068] Measure the propagation time of the satellite signal from transmission to reception, and obtain at least one set of pseudorange observations by calculating the time difference and multiplying it by the speed of light;

[0069] During the tracking phase of pseudorange measurements, the receiver simultaneously locks onto the carrier component of the satellite signal;

[0070] The receiver generates a local oscillation signal with the same frequency as the satellite carrier, and adjusts the phase and frequency of the local signal through a phase-locked loop to keep it synchronized with the received carrier signal;

[0071] The receiver measures the carrier phase difference at an initial moment, where the carrier phase difference includes a fractional part less than one cycle and a whole cycle.

[0072] After the local oscillator signal is synchronized with the received carrier signal, the receiver measures the carrier phase difference at the initial moment. The carrier phase difference contains the relative position information between the satellite and the receiver. However, due to the short wavelength of the carrier, the directly measured phase difference may be less than one week, that is, less than a complete carrier cycle. At the same time, there is also the problem of the number of whole cycles. The decimal part less than one week can be directly obtained through high-precision phase measurement technology, while the number of whole cycles needs to be determined through certain algorithms and technical means. The continuous tracking method can be used to record the changes in the carrier phase over a period of time, so as to calculate the number of whole cycles. The carrier phase observation value has high accuracy, but it is also easily affected by various errors, such as multipath effects, receiver noise, etc. Therefore, corresponding error processing and correction are required in practical applications.

[0073] Reference Figure 4 As shown, the navigation message is demodulated from the received satellite signal, and the precise position of each satellite at the current moment is calculated using the satellite orbit calculation model. Specifically, the following steps are involved:

[0074] Identify the subframe start mark of the navigation message, determine the message structure, integrate and judge each data bit, and recover the binary message;

[0075] Parse the message content and extract the satellite's orbital parameters and clock correction parameters;

[0076] Calculate the root of the ratio of the Earth's gravitational constant to the cube of the satellite's orbital semi-major axis, and output it as the satellite's average angular velocity;

[0077] Calculate the product of the average angular velocity and the difference between the current time and the message reference time, and output the sum of the average angular velocity and the initial position of the satellite as the mean anomaly angle;

[0078] Based on Kepler's equation, the value of the eccentric anomaly is solved according to the mean anomaly;

[0079] The true anomaly formula and the current orbital coordinate formula are used to calculate the true anomaly of the satellite and the coordinates of the current satellite in the orbital plane.

[0080] The Kepler equation is: ,

[0081] Where, is the mean anomaly angle, is the eccentric anomaly angle, is the eccentricity of the satellite orbit;

[0082] The true anomaly formula is: ,

[0083] Where, is the true anomaly angle;

[0084] The current orbit coordinate formula is: ,

[0085] Where, are the horizontal and vertical coordinates of the current satellite in the orbital plane, is the semi-major axis length of the satellite orbit;

[0086] If the satellite's coordinates in the orbital plane need to be converted to the geocentric inertial coordinate system or other coordinate systems, coordinate rotation is also required, taking into account parameters such as orbital inclination and right ascension of the ascending node. Ultimately, the satellite position after coordinate conversion can be output as three-dimensional coordinates in the geocentric coordinate system for use by the positioning algorithm.

[0087] Reference Figure 5 As shown, at at least one reference location, the 5G-Mesh signal strength is measured and averaged, a signal strength fingerprint database is constructed, and the arrival time of the signal from the Mesh node to the terminal device is measured. Specifically, the following steps are involved:

[0088] The target area is divided into regular grids, and the center point of each grid is recorded as the reference position;

[0089] Use a signal analyzer to measure the 5G-Mesh signal strength and remove outliers that deviate from the mean by more than 3 times the standard deviation;

[0090] Take the arithmetic average of the remaining data and record it as the signal strength fingerprint of the location;

[0091] The node sends a signal containing a transmission timestamp, the terminal records the reception timestamp, and replies with a response signal containing a reception timestamp, and the node records the reception timestamp of the response signal;

[0092] The signal arrival time formula is used to calculate the arrival time of the signal from the Mesh node to the terminal device.

[0093] Divide the target area into regular grids based on its size, shape, and positioning accuracy requirements. For example, if the target area is a square area 100 meters long and 100 meters wide, to ensure positioning accuracy, it can be divided into 10×10 grids, with each grid side being 10 meters long. The center point of each grid is recorded as the reference position, and each reference position is assigned a unique identifier, such as a number and coordinates, for subsequent data recording and management. The Mesh node sends a signal containing a transmission timestamp. The transmission timestamp can be obtained through the node's internal clock system and accurately records the moment the signal is transmitted. After receiving the signal, the terminal device records the reception timestamp. The terminal device also needs to have a high-precision clock system to ensure the accuracy of the reception timestamp. After receiving the signal, the terminal device replies with a response signal containing the reception timestamp. After receiving the response signal from the terminal device, the Mesh node records the reception timestamp of the response signal.

[0094] Reference Figure 6 As shown in the figure, when the terminal device is in the positioning state, the signal strength of the current position is measured in real time, and matched with the feature vector in the fingerprint database, and the reference position with the highest similarity to the current signal strength feature is output as the terminal position estimation. Specifically, it includes:

[0095] Compare the current signal strength list with each record in the fingerprint library one by one and calculate the degree of difference between the two;

[0096] Different weights are assigned to the signal strength of different nodes, with the master node having a higher weight;

[0097] The instantaneous speed of BeiDou is calculated through the continuous satellite positioning results, and the displacement change of the continuous fingerprint matching results is used to estimate the 5G-Mesh assisted speed;

[0098] Based on the fusion rule, the comprehensive mobile speed of the terminal device is calculated as the sum of 0.7 times the instantaneous speed of Beidou and 0.3 times the auxiliary speed of 5G-Mesh;

[0099] Determine whether the terminal's comprehensive moving speed is higher than three meters per second. If so, select the five records with the smallest differences as candidate locations. If not, select the three records with the smallest differences as candidate locations.

[0100] The coordinates of the candidate positions are averaged to obtain the final positioning result.

[0101] In a 5G-Mesh network, there is usually a division between master nodes and slave nodes. The master node plays a more important role in the network, and its signal strength is usually more stable and reliable. Therefore, the signal strength of the master node is given a higher weight. The difference between the current signal strength list and each record in the fingerprint library is calculated. Common methods for calculating the difference degree include Euclidean distance, Manhattan distance, or cosine similarity.

[0102] Reference Figure 7 As shown in the figure, based on ionospheric delay, tropospheric delay, satellite clock error and receiver clock error, the Beidou satellite signal error modeling is carried out. Based on multipath effect, signal shielding and node clock error, the 5G-Mesh network signal error modeling is carried out. Specifically, the following are included:

[0103] For dual-frequency receivers, the error caused by ionospheric delay is eliminated by using the relationship that ionospheric delay is inversely proportional to the square of the carrier frequency;

[0104] Based on the Sastamonen model, the error caused by tropospheric delay is calculated according to local temperature, pressure and relative humidity;

[0105] The satellite clock error is monitored in real time by ground monitoring stations, and the correction parameters are broadcast to users through navigation messages. Users use the correction parameters to correct the satellite clock error.

[0106] In the positioning solution, the receiver clock error is treated as an unknown number and solved together with the position parameters. The differential positioning technology is used to eliminate the receiver clock error through the clock error observation value between the reference station and the user station.

[0107] Adopt channel modeling technology to simulate the propagation path and attenuation characteristics of signals in complex environments, thereby eliminating errors caused by multipath effects;

[0108] Through field testing and simulation analysis, we can determine the signal blocking area and degree, and optimize the node layout in network planning.

[0109] The signal blocking factor is taken into account in the positioning algorithm, and the signal in the blocked area is weighted to eliminate the error caused by signal blocking.

[0110] The time synchronization protocol is used to achieve clock synchronization of Mesh network nodes. During the positioning process, the node clock error is monitored in real time and corrected through algorithms.

[0111] According to the Sastamonen model, local meteorological data such as temperature, pressure and relative humidity are first obtained. Using these meteorological data, the tropospheric delay value is calculated according to the calculation method specified by the model. Then, in the positioning solution process, this calculated value is used to correct the observation data to eliminate the tropospheric delay error. Using differential positioning technology, the reference station and the user station respectively obtain their own receiver clock errors and calculate the clock error observation value between the two, that is, the differential correction value. The user station corrects its own receiver clock error based on this differential correction value to eliminate the receiver clock error.

[0112] Furthermore, this solution also proposes a computer-readable storage medium on which a computer-readable program is stored. When the computer-readable program is called, it executes the above-mentioned high-precision positioning method based on Beidou satellite and 5G-Mesh joint.

[0113] It is understandable that the storage medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; an optical medium, such as a DVD; or a semiconductor medium, such as a solid state disk (SSD).

[0114] To sum up, the advantages of the present invention are: it greatly enhances the reliability of the positioning system, ensures that positioning services can be provided continuously and stably in various complex environments, improves the fault tolerance and robustness of the system, is of great significance for ensuring the safe operation of key applications, and has strong adaptability to different environments. Whether it is a densely populated urban area, an indoor environment or a remote area, it can flexibly adjust the positioning strategy according to the local environmental characteristics and signal conditions to achieve effective positioning.

[0115] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-precision positioning method based on BeiDou satellite and 5G-Mesh, characterized by: include: The terminal device has a built-in Beidou and 5G-Mesh signal fusion receiving module, which receives the navigation signals of Beidou satellites and the communication signals of the 5G-Mesh network in real time; By monitoring the topology changes of the 5G-Mesh network in real time and combining network performance indicators such as signal strength and transmission delay, the connection relationship between nodes is dynamically adjusted; The receiver performs pseudo-range measurements on the signals of visible satellites to obtain at least one set of pseudo-range observation values ​​and observes the carrier phase; Demodulate the navigation message from the received satellite signal and calculate the precise position of each satellite at the current moment using the satellite orbit calculation model. The navigation message includes the satellite's orbit parameters and clock correction parameters. At at least one reference location, measure the 5G-Mesh signal strength and take the average value to build a signal strength fingerprint database, and measure the arrival time of the signal from the Mesh node to the terminal device; When the terminal device is in the positioning state, it measures the signal strength of the current position in real time and matches it with the feature vector in the fingerprint database, and outputs the reference position with the highest similarity to the current signal strength feature as the terminal's position estimate; Error modeling is performed on BeiDou satellite signals based on ionospheric delay, tropospheric delay, satellite clock error, and receiver clock error. Error modeling is performed on 5G-Mesh network signals based on multipath effects, signal obstruction, and node clock error. The weighted fusion algorithm is used to fuse the two types of position information, and the corresponding weight is assigned to each position information according to the results of error modeling.

2. The high-precision positioning method based on BeiDou satellite and 5G-Mesh according to claim 1 is characterized in that: The real-time monitoring of topological changes in the 5G-Mesh network and the dynamic adjustment of the connection relationship between nodes based on network performance indicators specifically include: Use the network discovery protocol to regularly scan and identify each node in the 5G-Mesh network and its connection status, and record each node's ID, IP address, connection port, and neighbor node list information; Based on the node discovery results, a topology diagram of the 5G-Mesh network is constructed. In the diagram, nodes are recorded as devices in the network, and edges are recorded as the connection relationships between devices. Deploy performance monitoring agents on each node to collect and report network performance indicator data; Use time series analysis to process the collected network performance indicator data and predict the load of each node and connection; Combine the current topology with load forecast results to analyze bottlenecks and overloaded nodes in the network, evaluate the performance of each connection path, and determine which connections need to be adjusted. Based on topology analysis and load forecast results, formulate connection adjustment strategies, increase or decrease connections, change connection paths, and adjust node power.

3. The high-precision positioning method based on BeiDou satellite and 5G-Mesh according to claim 2 is characterized in that: The receiver performs pseudo-range measurement on the signal of the visible satellite to obtain at least one set of pseudo-range observation values, and observes the carrier phase, specifically including: The receiver searches for visible satellite signals by scanning the frequency band and identifying the satellite's pseudo-random noise code. Once the signal is successfully captured, the receiver locks onto the signal and enters the tracking phase. The receiver generates a local replica code synchronized with the satellite signal and adjusts the phase and frequency of the local code to align it with the received satellite signal. Measure the propagation time of the satellite signal from transmission to reception, and obtain at least one set of pseudorange observations by calculating the time difference and multiplying it by the speed of light; During the tracking phase of pseudorange measurements, the receiver simultaneously locks onto the carrier component of the satellite signal; The receiver generates a local oscillation signal with the same frequency as the satellite carrier, and adjusts the phase and frequency of the local signal through a phase-locked loop to keep it synchronized with the received carrier signal; The receiver measures the carrier phase difference at an initial moment, where the carrier phase difference includes a fractional part less than one cycle and a whole cycle.

4. The high-precision positioning method based on BeiDou satellite and 5G-Mesh joint according to claim 3 is characterized in that: Demodulating the navigation message from the received satellite signal and calculating the precise position of each satellite at the current moment using a satellite orbit calculation model specifically includes: Identify the subframe start mark of the navigation message, determine the message structure, integrate and judge each data bit, and recover the binary message; Parse the message content and extract the satellite's orbital parameters and clock correction parameters; Calculate the root of the ratio of the Earth's gravitational constant to the cube of the satellite's orbital semi-major axis, and output it as the satellite's average angular velocity; Calculate the product of the average angular velocity and the difference between the current time and the message reference time, and output the sum of the average angular velocity and the initial position of the satellite as the mean anomaly angle; Based on Kepler's equation, the value of the eccentric anomaly is solved according to the mean anomaly; The true anomaly formula and the current orbital coordinate formula are used to calculate the true anomaly of the satellite and the coordinates of the current satellite in the orbital plane.

5. The high-precision positioning method based on BeiDou satellite and 5G-Mesh according to claim 4 is characterized in that: The measuring of the 5G-Mesh signal strength at at least one reference location and taking an average value, constructing a signal strength fingerprint database, and measuring the arrival time of the signal from the Mesh node to the terminal device specifically includes: The target area is divided into regular grids, and the center point of each grid is recorded as the reference position; Use a signal analyzer to measure the 5G-Mesh signal strength and remove outliers that deviate from the mean by more than 3 times the standard deviation; Take the arithmetic average of the remaining data and record it as the signal strength fingerprint of the location; The node sends a signal containing a transmission timestamp, the terminal records the reception timestamp, and replies with a response signal containing a reception timestamp, and the node records the reception timestamp of the response signal; The signal arrival time formula is used to calculate the arrival time of the signal from the Mesh node to the terminal device.

6. The high-precision positioning method based on BeiDou satellite and 5G-Mesh according to claim 5, characterized in that: When the terminal device is in the positioning state, the signal strength of the current position is measured in real time, and matched with the feature vector in the fingerprint database, and the reference position with the highest similarity to the current signal strength feature is output as the terminal position estimation, which specifically includes: Compare the current signal strength list with each record in the fingerprint library one by one and calculate the degree of difference between the two; Different weights are assigned to the signal strength of different nodes, with the master node having a higher weight; The instantaneous speed of BeiDou is calculated through continuous satellite positioning results, and the displacement change of continuous fingerprint matching results is used to estimate the 5G-Mesh assisted speed; Based on the fusion rule, the comprehensive mobile speed of the terminal device is calculated as the sum of 0.7 times the instantaneous speed of Beidou and 0.3 times the auxiliary speed of 5G-Mesh; Determine whether the terminal's comprehensive moving speed is higher than three meters per second. If so, select the five records with the smallest differences as candidate locations. If not, select the three records with the smallest differences as candidate locations. The coordinates of the candidate positions are averaged to obtain the final positioning result.

7. The high-precision positioning method based on BeiDou satellite and 5G-Mesh joint according to claim 6 is characterized in that: The error modeling of BeiDou satellite signals based on ionospheric delay, tropospheric delay, satellite clock error, and receiver clock error, and the error modeling of 5G-Mesh network signals based on multipath effects, signal shielding, and node clock error specifically include: For dual-frequency receivers, the error caused by ionospheric delay is eliminated by using the relationship that ionospheric delay is inversely proportional to the square of the carrier frequency; Based on the Sastamonen model, the error caused by tropospheric delay is calculated according to local temperature, pressure and relative humidity; The satellite clock error is monitored in real time by ground monitoring stations, and the correction parameters are broadcast to users through navigation messages. Users use the correction parameters to correct the satellite clock error. In the positioning solution, the receiver clock error is treated as an unknown number and solved together with the position parameters. The differential positioning technology is used to eliminate the receiver clock error through the clock error observation value between the reference station and the user station. Adopt channel modeling technology to simulate the propagation path and attenuation characteristics of signals in complex environments, thereby eliminating errors caused by multipath effects; Through field testing and simulation analysis, we can determine the signal blocking area and degree, and optimize the node layout in network planning. The signal blocking factor is taken into account in the positioning algorithm, and the signal in the blocked area is weighted to eliminate the error caused by signal blocking. The time synchronization protocol is used to achieve clock synchronization of Mesh network nodes. During the positioning process, the node clock error is monitored in real time and corrected through algorithms.

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