An indoor and outdoor integrated positioning method and system based on Beidou satellite navigation

Abstract

The present invention discloses an indoor and outdoor integrated positioning method and system based on Beidou satellite navigation, which mainly relates to the field of navigation technology, wherein the method includes: using 5G communication technology and Beidou satellite navigation system to locate the terminal receiver, and obtaining positioning data, wherein the positioning data includes time information and distance information; using Chan algorithm to process the positioning data, and obtaining first position information data; defining and using weighting coefficients to adjust the first position information data to obtain final position information data. The present invention solves the problems of low positioning accuracy, single application scenario, and unstable satellite signal of the current Beidou satellite navigation system in non-exposed space, and realizes the integration of indoor and outdoor navigation, positioning, and communication functions in the environment of mega-city rail transit.

Description

Technical Field

[0001] The present invention belongs to the field of navigation technology, and in particular relates to an indoor and outdoor integrated positioning method and system based on Beidou satellite navigation. Background Art

[0002] The existing Beidou satellite system positioning technology is as follows: the Beidou satellite terminal receiver obtains multiple satellite signals and uses the time interval of each satellite signal to calculate the distance between each satellite and the terminal receiver, and then uses the intersection method to calculate the three-dimensional coordinates of the terminal receiver to achieve navigation positioning. Although the BDS outdoor positioning service has reached a satisfactory level of technical maturity, in the complex environment of the indoor and outdoor boundary areas, a single positioning technology is difficult to cover indoor and outdoor spaces at the same time and cannot meet the overall accuracy requirements. The positioning performance is insufficient under indoor and occluded conditions, and it is impossible to achieve a smooth transition and seamless connection of positioning technology, algorithms, accuracy and coverage in multiple scenarios.

[0003] The Beidou satellite navigation system has low power in indoor / outdoor blocked areas and the distance between the satellite and the ground is far. When ground users receive satellite signals, the signals are relatively weak. If they are underground or in tunnels, they will not be able to receive navigation signals due to the influence of various environmental factors during signal propagation. Beidou satellite navigation signals are easily interfered by electromagnetic signals. In addition, buildings block the signal source, weakening signal coverage, resulting in large positioning errors and inability to accurately locate. Satellites in the Beidou navigation system operate according to specific orbits and cannot achieve continuous coverage of remote areas. They have weak adaptability to terrain. In addition, since user capacity depends on factors such as the satellite's available bandwidth, signal modulation and coding methods, and the computing speed of the ground center station, problems such as limited capacity, network instability, and positioning delays occur in actual specific applications. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present invention proposes an indoor and outdoor integrated positioning method and system based on Beidou satellite navigation.

[0005] In a first aspect, the present invention provides an indoor and outdoor integrated positioning method based on Beidou satellite navigation, comprising the following steps:

[0006] Step S1: Using 5G communication technology and Beidou satellite navigation system to locate the terminal receiver to obtain positioning data, where the positioning data includes time information and distance information;

[0007] Step S2: Processing the positioning data using the Chan algorithm to obtain first position information data;

[0008] Step S3: defining and using a weighting coefficient to adjust the first position information data to obtain final position information data.

[0009] After the step of processing the positioning data using the Chan algorithm to obtain the first position information data, the following steps are further performed:

[0010] Step S2.A: using the Taylor series expansion method to recursively calculate the first position information data using the positioning data to obtain the measurement error of the terminal receiver coordinates;

[0011] Step S2.B: Compare the measurement error with a preset threshold value. If it is greater than the threshold value, return to step S2, use the first position information data as positioning data, and continue to use the Chan algorithm for processing; if it is less than the threshold value, go to step S3.

[0012] The method of using 5G communication technology and Beidou satellite navigation system to locate the terminal receiver includes the following steps:

[0013] Step S1.1: Synchronize the terminal receiver and BeiDou satellite;

[0014] Step S1.2: Measure the distance between the Beidou satellite and the terminal receiver;

[0015] Step S1.3: Find the Beidou satellite position and determine the number of terminal receivers receiving signals from the same Beidou satellite;

[0016] Step S1.4: Multilateration of the terminal receiver.

[0017] The synchronization terminal receiver and the Beidou satellite are synchronized by using the FTSP time synchronization algorithm, specifically, the terminal receiver and the Beidou satellite are synchronized by broadcasting synchronization messages unidirectionally between the reference node and the node to be synchronized.

[0018] The synchronization terminal receiver and Beidou satellite comprises the following steps:

[0019] Step S1.1.1: Allocate a unique identification number to all nodes in the entire network as an identifier, and use the root node of the entire wireless sensor network as a reference node for time synchronization;

[0020] Step S1.1.2: The root node marks its own synchronization information with a timestamp and sends it to all nodes to be synchronized within the communication range in a flooding manner. After receiving the synchronization information, the nodes to be synchronized parse the timestamp therein, calculate the clock offset, adjust the local time to the reference time, and complete the time synchronization;

[0021] Step S1.1.3: All nodes to be synchronized refer to the root node and use themselves as reference nodes to broadcast synchronization messages within the communication range. The synchronization messages contain two timestamp information. All unsynchronized nodes complete their own time synchronization after receiving the timestamp information. The synchronized nodes determine the synchronization level according to the timestamp information.

[0022] Step S1.1.4: Determine whether all nodes in the entire network have received the synchronization message. If not, go to step S1.1.1. If yes, exit.

[0023] The positioning data is processed using the Chan algorithm, and the final calculation formula obtained is as follows:

[0024]

[0025] Where Z is the approximate solution of the TDOA covariance matrix, Ψ is the covariance matrix of the vector error, G is the distance difference matrix, h is the distance difference error matrix, T represents the transposed matrix, and a is the number of iterations.

[0026] The Taylor series expansion method is used to recursively calculate the first position information data using the positioning data to obtain the measurement error of the terminal receiver coordinates. The calculation formula is as follows:

[0027]

[0028] Among them, δ is the solution of the least squares vector error, Q is the covariance matrix of TDOA, Δx is the measurement error between the i-th node position information and the first position information data in the x-axis direction, △y is the measurement error between the i-th node position information and the first position information data in the y-axis direction, and i is the number of the terminal receiver.

[0029] The calculation formula of the weighting coefficient is as follows:

[0030]

[0031] Where η is the weighting coefficient, n is the number of measurements, l is the number of reference terminal receivers, and △R is the square of the difference between the measured value and the estimated value of the reference terminal receiver positioning coordinates.

[0032] In a second aspect, the present invention provides an indoor and outdoor integrated positioning system based on Beidou satellite navigation, comprising: a positioning data acquisition module, a first position information data acquisition module and a final position information data acquisition module, each module being connected in sequence;

[0033] The positioning data acquisition module is used to use 5G communication technology and Beidou satellite navigation system to locate the terminal receiver and obtain positioning data, wherein the positioning data includes time information and distance information;

[0034] The first location information data acquisition module is used to process the positioning data using a Chan algorithm to obtain first location information data;

[0035] The final position information data acquisition module is used to define and use a weighting coefficient to adjust the first position information data to obtain the final position information data.

[0036] In a third aspect, the present invention provides a computer-readable storage medium, which stores computer program instructions. When the computer-readable storage medium runs on a computer, it enables the computer to execute the indoor and outdoor integrated high-precision positioning method based on Beidou satellite navigation.

[0037] Compared with the prior art, the present invention has the following beneficial technical effects:

[0038] 1. The present invention provides an indoor and outdoor high-precision positioning method, which realizes that Beidou satellite signals can fully cover indoor / outdoor shielded areas (such as complex environments such as under viaducts, tunnels, tree-shaded areas, and urban canyons) based on indoor and outdoor integrated application scenarios, and has high positioning accuracy, little influence from other electromagnetic signal interference / building shielding, and stable signal transmission; a time synchronization method provided therein solves the errors generated during signal transmission.

[0039] 2. The present invention is based on the Beidou satellite navigation system and uses the FTSP time synchronization algorithm and the Chan-Taylor hybrid algorithm to solve the problems of low positioning accuracy, single application scenario, unstable satellite signals, etc. of the Beidou satellite navigation system in non-exposed space, and realizes the integration of indoor and outdoor navigation, positioning, and communication functions, becoming a terminal positioning method that can be applied to a variety of complex environments.

[0040] 3. The present invention adopts 5G communication technology and utilizes its characteristics such as ultra-large bandwidth, ultra-low latency and massive connection communication capabilities to improve the user capacity and data processing rate of the Beidou satellite navigation system, solve the problems of network instability and congestion, and expand the application capabilities of Beidou.

[0041] 4. The present invention adopts the FTSP synchronization algorithm to achieve full network synchronization by broadcasting synchronization messages between the reference node and the node to be synchronized. It has low power consumption, high accuracy, good scalability and robustness, is easy to use in complex indoor environments, and achieves high-precision time measurement.

[0042] 5. The present invention adopts the Chan algorithm, utilizes all the measured data, and uses functions to form expressions for calculation, so as to obtain more accurate location information data. Even in a bad channel environment, it can well reflect the estimation of the initial location information, and is beneficial to improving the accuracy and running speed of the Taylor algorithm.

[0043] 6. The present invention adopts the Taylor series expansion method, recursively calculates the obtained measurement data with the initial position information, and then solves the iterative part with the least squares method. By controlling the measurement error of the node to be measured within the threshold value, the positioning technology has better noise resistance, reduces the impact of noise on Beidou satellite signal transmission, and improves the stability of satellite signals.

[0044] 7. The present invention defines weighted coefficients and adjusts data through iterative calculations to make positioning more accurate, thereby obtaining more precise location information.

[0045] In summary, the method and system of the present invention realize the integration of indoor and outdoor navigation, positioning and communication in the mega-city rail transit environment through the combination of Beidou satellite and 5G communication technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a flow chart of an indoor and outdoor integrated positioning method based on Beidou satellite navigation according to an embodiment of the present invention;

[0047] Figure 2 A principle block diagram of an indoor and outdoor integrated positioning system based on Beidou satellite navigation according to an embodiment of the present invention;

[0048] Figure 3 A flowchart of iterative optimization of positioning data of a terminal receiver under test according to an embodiment of the present invention;

[0049] Figure 4 This is a simulation comparison diagram of the accuracy of three algorithms when the noise standard deviation is 0.2 in an embodiment of the present invention;

[0050] Figure 5 This is a simulation comparison diagram of the accuracy of three algorithms when the noise standard deviation of the embodiment of the present invention is 0.4;

[0051] Figure 6 This is a simulation comparison diagram of the accuracy of three algorithms when the noise standard deviation of the embodiment of the present invention is 0.6;

[0052] Figure 7 This is a simulation comparison diagram of the accuracy of three algorithms when the noise standard deviation is 0.4 and there are 5 terminal receivers in an embodiment of the present invention;

[0053] Figure 8 This is a simulation comparison diagram of the accuracy of three algorithms when the noise standard deviation of the embodiment of the present invention is 0.4 and there are 6 terminal receivers;

[0054] Fig. 9 This is a comparison chart of RMSE between the Chan algorithm and the Chan-Taylor hybrid algorithm when the noise standard deviation increases according to an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0056] When the Beidou satellite navigation system transmits signals in a complex environment, it is often interfered by electromagnetic signals or blocked by buildings, which reduces the positioning accuracy and increases the error. The present invention is based on the Beidou satellite navigation and positioning system, uses the FTSP (Flooding Time Synchronization Protocol) time synchronization algorithm to synchronize the signal sending end and the signal receiving end, and then uses the Chan-Taylor hybrid algorithm to process the measurement data, thereby improving the navigation and positioning accuracy of ground users, reducing the influence of electromagnetic signals and noise, and expanding the navigation and visual range of the system, thereby realizing indoor and outdoor integrated high-precision positioning measurement.

[0057] Now the present invention is described in detail in conjunction with specific embodiments as follows:

[0058] In the first aspect, the present invention provides an indoor and outdoor integrated positioning method based on Beidou satellite navigation, such as Figure 1 As shown, the following steps are included:

[0059] Step S1: Using 5G communication technology and Beidou satellite navigation system to locate the terminal receiver to obtain positioning data, where the positioning data includes time information and distance information;

[0060] Step S2: Processing the positioning data using the Chan algorithm to obtain first position information data;

[0061] Step S3: defining and using a weighting coefficient to adjust the first position information data to obtain final position information data.

[0062] In step S1, the terminal receiver is positioned using 5G communication technology and the Beidou satellite navigation system, which mainly includes the following steps:

[0063] Step S1.1: A-BDS synchronizes the terminal receiver and BeiDou satellite;

[0064] Step S1.2: A-BDS extracts the positioning data.

[0065] In a possible embodiment, the specific implementation is as follows:

[0066] Step 101: Turn on the A-BDS (Assisted-BeiDou Navigation Satellite System) and the terminal receiver at a certain moment, and record the time;

[0067] Step 102: A-BDS obtains the position of the terminal receiver and monitors and tracks Beidou satellite signals;

[0068] Step 103: The terminal receiver receives the Beidou satellite signal, measures the time when the Beidou satellite signal arrives at the terminal receiver, calculates the pseudorange and returns the A-BDS;

[0069] Pseudorange refers to the pseudo-range, which is the approximate distance between the terminal receiver and the Beidou satellite during the Beidou satellite positioning process. Assuming that the Beidou satellite clock and the receiver clock are strictly synchronized, the propagation time of the Beidou satellite signal can be obtained based on the transmission time of the Beidou satellite signal and the reception time of the Beidou satellite signal by the terminal receiver, and then multiplied by the speed of light to obtain the distance between the Beidou satellite and the terminal receiver.

[0070] Step 104: Synchronize the terminal receiver and the Beidou satellite.

[0071] In another embodiment, it is obvious that after turning on the Beidou terminal receiver, it is also possible to directly determine whether the terminal receiver and the Beidou satellite are time synchronized without enabling the Beidou satellite navigation system server. If synchronized, proceed directly to the next step to measure the distance between the Beidou satellite and the terminal receiver. If not synchronized, continue to return to continue comparing and judging until synchronization is achieved.

[0072] The synchronization terminal receiver and the Beidou satellite are synchronized by using the FTSP time synchronization algorithm, specifically by unidirectionally broadcasting synchronization messages between the reference node and the node to be synchronized.

[0073] In this embodiment, terminal receivers are regarded as nodes in the system. Unless otherwise specified, the following nodes are all terminal receivers.

[0074] The synchronization terminal receiver and Beidou satellite also include the following steps:

[0075] Step S1.1.1: Use the unique ID (Identity document) assigned to all nodes in the entire network as an identifier, and use the root node of the entire wireless sensor network as a reference node for time synchronization, that is, the root node represents the terminal receiver as a reference;

[0076] Step S1.1.2: The root node marks its own synchronization information with a timestamp and sends it to all nodes to be synchronized within the communication range in a flooding manner. After receiving the synchronization information, the nodes to be synchronized parse the timestamp therein, calculate the clock offset, adjust the local time to the reference time, and complete the time synchronization;

[0077] Step S1.1.3: All nodes to be synchronized refer to the root node and use themselves as reference nodes to broadcast synchronization messages within the communication range. The synchronization messages contain two timestamp information. All unsynchronized nodes complete their own time synchronization after receiving the timestamp information. The synchronized nodes determine the synchronization level according to the timestamp information.

[0078] Step S1.1.4: Determine whether all nodes in the entire network have received the synchronization message. If not, go to step S1.1.1. If yes, exit.

[0079] The steps of extracting the positioning data in this embodiment are as follows:

[0080] Step 105: Measure the distance between the Beidou satellite and the terminal receiver;

[0081] Step 106: Find the Beidou satellite position and determine the number of terminal receivers receiving signals from the same Beidou satellite;

[0082] Step 107: Multilateration positioning of the terminal receiver;

[0083] Step 108: The terminal receiver obtains positioning data;

[0084] Step 109: A-BDS extracts positioning data.

[0085] In step 105, the distance between the Beidou satellite and the terminal receiver is measured. Specifically, the Beidou satellite and the terminal receiver simultaneously generate and send the same pseudo-random code or signal, and achieve time synchronization. The terminal receiver can measure the delay according to the difference between the two sets of pseudo-codes, and multiply the measured delay by the speed of light to obtain the distance between the Beidou satellite and the terminal receiver.

[0086] It should be noted that in step 105, the A-BDS needs to determine whether the distance between the Beidou satellite and the terminal receiver is the measurement distance. The determination method here is a prior art and will not be described in detail in this application. If yes, step 106 is executed, if not, step 105 is executed;

[0087] Similarly, in the process of finding the Beidou satellite position in step 106, the A-BDS should determine whether the Beidou satellite position is found. The Beidou satellite position is specifically determined by the known node position and the distance between the Beidou satellite and the node to be measured. This determination method is a prior art, so it is not repeated here. If yes, step 107 is executed, if not, step 106 is continued;

[0088] In step 107, the terminal receivers are multi-laterally positioned. The terminal receivers all receive signals sent by the same Beidou satellite, and the number of terminal receivers within the Beidou satellite signal transmission range can be known by determining the Beidou satellite positions.

[0089] The principle of multi-lateral positioning is as follows: Assume that the real coordinates of the node U to be measured are (x, y); the known nodes M1, M2, ..., M i The positions are: (x1,y1),(x2,y2),…,(x i ,y i ); Through field investigation and survey, the actual distances from the node to be tested U to each node are: z1, z2, ..., z i ; The measured distance information from the node U to each node is obtained by multiplying the signal propagation speed and the time required for the propagation process: d1, d2, ..., d i , according to the geometric relationship of the two-dimensional plane:

[0090]

[0091] Now, a terminal receiver is used as a reference, and its position information is fixed. Other terminal receivers use this terminal receiver as a reference. The time difference of signal transmission can be obtained according to the time recorded before and after this terminal receiver receives the signal. The distance difference can be obtained by multiplying the measured time with the transmission speed. Based on these data, an equation can be established. The following embodiment takes three terminal receivers as an example to describe in detail the process of calculating the positioning data of a terminal receiver to be tested:

[0092] Assume that three terminal receivers are M1, M2, and M3, and their position coordinates are (x1, y1), (x2, y2), and (x3, y3), respectively. The position coordinates of the terminal receiver U to be tested are (x, y). We can get:

[0093]

[0094] By solving the equation, we can get:

[0095]

[0096] Wherein, d1, d2, and d3 are respectively the measurement distances from the terminal receiver U to be tested to the terminal receivers M1, M2, and M3;

[0097] z1, z2, z3 are the real distances from the terminal receiver U to be tested to the terminal receivers M1, M2, M3;

[0098] d 21 is the distance from terminal receiver M2 to M1; d 31 is the distance from terminal receiver M3 to M1;

[0099] After repeated experiments, the measurement data of the terminal receiver to be tested each time is obtained through the above calculation A-BDS, which is used as the terminal receiver positioning data for time synchronization to be processed in the next step.

[0100] After A-BDS obtains the positioning data, we need to correct the observed positioning data. The specific positioning error correction process is: fix a certain terminal receiver to be tested as a reference node, process the positioning data of this reference node obtained by A-BDS through the Chan algorithm, use the obtained coordinate data as the first position information data, adjust the first position information data through weighted correction, and obtain the positioning result; in order to further obtain higher positioning accuracy, the present application can also use a function to represent the connection between the terminal receiver to be tested and the signals of other terminal receivers, perform Taylor series expansion of the function using the first position information data, and then obtain the vector error calculation formula through calculation according to the formula in the Chan algorithm, thereby obtaining the least squares solution of the formula, and perform iterative correction by comparing the measurement error value determined in this way with the preset threshold value. Specifically, determine whether the comparison result meets the requirements. If not, return to the processing step using the Chan algorithm and enter the next cycle. If it meets the requirements, output the positioning result of the terminal receiver to be tested.

[0101] We use the Chan-Taylor hybrid algorithm to process the obtained positioning data as follows:

[0102] In step S2, the positioning data is processed using the Chan algorithm to obtain first position information data; the details are as follows:

[0103] The Chan algorithm is used to calculate the time difference of multiple node signals received in a certain measurement and the distance difference between multiple nodes to obtain a more accurate location information data as the first location information data; the specific steps are as follows:

[0104] Step S2.1: The coordinates of the node to be measured are represented by (x, y), and the i-th node position is represented by (x i ,y i ) and the distance between them is represented by Ri Indicates that We can get:

[0105]

[0106] Step S2.2: Let R i,1 is the distance difference between the node to be tested and nodes i and 1, we can get:

[0107]

[0108]

[0109] Step S2.3: Let i = 1, then R i,1 =0,

[0110] have to:

[0111] Step S2.4: Subtract ② from formula ① to get:

[0112] From this we can get the vector error:

[0113] Where:

[0114] Among them, K is the Rice factor, K i represents the square of the distance between the ith node and the node to be tested; Z 0 It represents the error between the measured value and the actual value of the position of the node to be measured; G is the distance difference matrix; h is the distance difference error matrix, that is, the deviation between the measured distance difference between two nodes and the node to be measured and the actual distance difference; Z represents the approximate solution of the TDOA covariance matrix, and a is the number of iterations.

[0115] Step S2.5: Since the measured value consists of the accurate value plus the error, we can get: The vector error is then:

[0116]

[0117] in represents the distance in Euclidean space; c represents the speed of light; n represents the number of measurements;

[0118] because So its covariance matrix is:

[0119] Ψ=E[ψψ Τ ]=c 2 BQB

[0120] E represents the identity matrix;

[0121] Therefore, the covariance matrix of TDOA (Time Difference of Arrival) is:

[0122] Q=E[nn],

[0123] The approximate solution formula of the measured value obtained by the least squares method is:

[0124]

[0125] Solving this equation yields x, y, and the first position information data.

[0126] It can be understood that in order to obtain higher precision positioning data, after the step of processing the positioning data using the Chan algorithm to obtain the first position information data, the present application further performs the following steps:

[0127] Step S2.A: using the Taylor series expansion method to recursively calculate the first position information data using the positioning data to obtain the measurement error of the terminal receiver coordinates;

[0128] Step S2.B: Compare the measurement error with a preset threshold value. If it is greater than the threshold value, return to step S2, use the first position information data as positioning data, and continue to use the Chan algorithm for processing; if it is less than the threshold value, go to step S3.

[0129] In another embodiment, the relationship between the node to be tested and the signal of the i-th node is expressed by a function f i (x,y,x i ,y i ) is expressed by M i Represents the measured value of the function, that is, the measured value of the node coordinates to be measured (x, y):

[0130]

[0131] where e i is the measurement error, is the true value.

[0132] Let μ represent the threshold value, then when e i =|△x+△y|<μ, the requirement is met, and the calculation result (x, y) is the first position information data, and the process goes to step S3 to continue weighted adjustment;

[0133] If the requirements are not met, the process returns to step S2 and the new positioning data, ie, the first position information data that does not meet the requirements, continues to be processed using the Chan algorithm.

[0134] The specific calculation process of △x and △y is described as follows:

[0135] Let the initial coordinate value of the node to be measured be (x0, y0), and the coordinate of the node to be measured calculated by step S2 is (x, y), and x = x0 + △x, y = y0 + △y. Perform Taylor series expansion on the function at (x0, y0), and the result is as follows:

[0136] The terms greater than two can be ignored because they are much smaller than the other parts, and the above formula can be simplified to:

[0137]

[0138] According to the formula in step 2.4:

[0139] We get: ψ = h i -G i δ;

[0140] in,

[0141] Where R i (i=2,3,…,k) represents the distance between the i-th node and the node to be measured during the iteration process, and k is the total number of terminal receivers covered by the satellite;

[0142] From this we can get the least squares solution of the above equation:

[0143]

[0144] Among them, δ is the solution of the least squares vector error; Q is the covariance matrix of TDOA; Δx is the measurement error between the i-th node position information and the first position information data in the x-axis direction; Δy is the measurement error between the i-th node position information and the first position information data in the y-axis direction, and i is the number of the terminal receiver.

[0145] In step S3, a weighting coefficient is defined and used to adjust the first position information data to obtain final position information data.

[0146] The specific calculation of this embodiment is as follows:

[0147] Let (x(n), y(n)) be the coordinate value obtained by the nth measurement, is the distance difference between the nth measurement value and the estimated value of the coordinates of the reference terminal receiver numbered i obtained by calculating between the terminal receiver numbered 1 and the reference terminal receiver numbered i (i.e., the i-th terminal receiver to be measured), and it can be obtained that:

[0148]

[0149] The square of the difference between the measured value and the estimated value of the receiver coordinates of the i-th terminal to be tested is defined as △R:

[0150] Thus, the weighting coefficient η(n) can be defined as:

[0151]

[0152] Where l is the number of reference terminal receivers, n is the number of measurements, and △R is the square of the difference between the reference terminal receiver positioning coordinate measurement value and the estimated value;

[0153] The final coordinate results are as follows:

[0154]

[0155] k is the total number of terminal receivers covered by the satellite;

[0156] The above steps of this embodiment are all solved by the least square method. In the further process of outputting the final positioning result of the node to be measured, the threshold value is set to make a standard determination, and the position coordinate measurement error of the node to be measured after correction is controlled within the threshold value to achieve the best optimization effect of the positioning calculation, such as Figure 3 As shown, the specific steps are as follows:

[0157] Step 110: obtaining coordinate data of a terminal receiver through the A-BDS, and calculating the coordinate data through the Chan algorithm to obtain first position information data of the terminal receiver;

[0158] Step 111: fix the terminal receiver as a reference node, express the relationship between it and other terminal receiver node signals by a function, perform Taylor series expansion on the function using the first position information data, and then calculate according to the vector error calculation formula obtained by calculation in the Chan algorithm to obtain the measurement error;

[0159] Step 112: determine whether the measurement error is less than a threshold value, if so, execute step 113, if not, use the first position information data as coordinate data and execute step 110;

[0160] Step 113: Correcting and adjusting the first position information data after iterative calculation by defining a weighting coefficient to obtain a final positioning result of the terminal receiver;

[0161] Step 114: Output the final positioning result of the terminal receiver.

[0162] In a second aspect, the present invention provides an indoor and outdoor integrated positioning system based on Beidou satellite navigation, such as Figure 2As shown, it includes: a positioning data acquisition module, a first position information data acquisition module and a final position information data acquisition module, and each module is connected in sequence;

[0163] The positioning data acquisition module is used to use 5G communication technology and Beidou satellite navigation system to locate the terminal receiver and obtain positioning data, which includes time information and distance information;

[0164] The first location information data acquisition module is used to process the positioning data using a Chan algorithm to obtain first location information data;

[0165] The final position information data acquisition module is used to define and use a weighting coefficient to adjust the first position information data to obtain the final position information data.

[0166] Comparison of simulation results of the embodiment:

[0167] The following is a simulation comparison chart of four terminal receivers using the Chan algorithm, Taylor algorithm and Chan-Taylor hybrid weighted algorithm. Figure 4 This is a comparison chart with a noise standard deviation of 0.2. Figure 5 This is a comparison chart when the noise standard deviation is 0.4. Figure 6 This is a comparison chart when the noise standard deviation is 0.6. The results are as follows:

[0168] When the noise standard deviation is 0.2, it is not difficult to find that the positioning accuracy of the Chan algorithm, Taylor algorithm and improved algorithm is not much different, but with the increase of noise, especially when the noise standard deviation is 0.6, the advantage of the Chan-Taylor algorithm is reflected, which is better than the two traditional algorithms. The experimental results show that in the same noise environment, the positioning accuracy of the improved Chan-Taylor hybrid algorithm proposed in this application is better than the other two algorithms.

[0169] Since the Chan algorithm can increase the number of base stations and improve positioning accuracy by adding redundant items, and the advantages of the improved algorithm cannot be well reflected when the noise is too small and the channel environment is good, and it is not consistent with the normal test environment when it is too high, we chose to conduct the experiment when the noise standard deviation is 0.4. Here we compare the simulation results of the three algorithms with different numbers of terminal receivers when the noise standard deviation is 0.4. Figure 7 This is a comparison chart of the accuracy of five receivers when the noise standard deviation is 0.4. Figure 8 The following is a comparison of the accuracy of the six receivers when the noise standard deviation is 0.4. The results are as follows:

[0170] from Figure 4 , Figure 7 as well as Figure 8It can be found that when the noise standard deviation is 0.4, the positioning accuracy can be increased by increasing the number of base stations. When there are four base stations, the positioning accuracy of the improved Chan-Taylor algorithm is the highest. As the number of base stations increases, the positioning accuracy advantage of the improved Chan-Taylor algorithm decreases, but it is still the highest.

[0171] The Chan algorithm and the Chan-Taylor hybrid algorithm are compared in the simulation experiment of static coordinate positioning of four terminal receivers. The coordinates of the four base stations are set to the coordinates of the main base station (0,0), the coordinates of the other base stations are (5,0), (5,5), (0,5), and the coordinates of the tag are (1,2). The noise is gradually increased from 0.01 to 1 for the experiment. The simulation results are shown in Figure 2. Fig. 9 As shown in the figure, TDOA-CHAN is the arrival time difference of the Chan algorithm, and TDOA-Chan&Taylor is the arrival time difference of the Chan-Taylor hybrid algorithm. It can be seen from the figure that when the noise standard deviation is very small, that is, when the noise standard deviation is less than 0.1, the root mean square error (RMSE value in the figure) of the two algorithms is basically the same, but as the noise standard deviation gradually increases, the root mean square error of the Chan algorithm becomes larger and larger, while the root mean square error of the improved Chan-Taylor hybrid algorithm increases relatively less. When the noise standard deviation is greater than 0.5, the change in the root mean square error of the Chan algorithm is much higher than that of the improved Chan-Taylor hybrid algorithm. This is because the Chan algorithm has poor noise resistance, while the improved Chan-Taylor hybrid algorithm is relatively less affected by noise due to the application of the Taylor series expansion method, which can greatly improve the accuracy.

[0172] According to the above experiments, we can get Table 1:

[0173] Table 1 Comparison of the root mean square error of the three algorithms under different noise standard deviations and different numbers of terminal receivers

[0174]

[0175] By analyzing the entire simulation experiment and data results: In the same noise environment, or under the same number of terminal receivers, the Chan-Taylor hybrid algorithm has higher accuracy than the traditional algorithm. The higher the accuracy of the positioning result, when the experimental noise standard deviation is 0.4 and the number of terminal receivers is 6, the simulation results show that the improved algorithm is about 0.07m and 0.2m higher than the traditional Chan algorithm and Taylor series expansion method respectively. Also comparing the three algorithms, the Chan algorithm only needs two least squares methods to calculate the result, so the amount of calculation is small.

[0176] The Chan-Taylor hybrid algorithm needs to first perform the Chan algorithm to obtain the first position information data, and then substitute it into the Taylor series expansion method, and add the weighted coefficient operation. The speed will be slightly lower than the Chan algorithm, but it can reach the threshold set by the program faster than the traditional Taylor series expansion method. Therefore, compared with the traditional Taylor series expansion method, the improved Chan-Taylor hybrid algorithm has improved both the operation speed and positioning accuracy.

[0177] Through the above simulation, it can be concluded that the improved Chan-Taylor hybrid algorithm significantly improves the Taylor algorithm's estimation of the initial position. The accuracy of the algorithm is improved as the accuracy of the initial position estimation is improved. At the same time, as the noise increases, the improved algorithm can also adapt better and has higher positioning accuracy.

[0178] In a third aspect, the present invention provides a computer-readable storage medium, which stores computer program instructions. When the computer-readable storage medium runs on a computer, it enables the computer to execute the indoor and outdoor integrated high-precision positioning method based on Beidou satellite navigation.

[0179] The present invention proposes a large-scale network high-precision time synchronization algorithm based on Beidou satellite navigation, which realizes the integration of Beidou + 5G positioning, time synchronization and communication in a super-large city rail transit environment for the first time, improves the accuracy of navigation positioning, etc., builds an indoor and outdoor integrated high-precision time synchronization network test platform, simulates the time synchronization and communication environment of subway production, generates signal flow and information flow similar to the scene, and verifies the rationality of the indoor and outdoor integrated high-precision time synchronization technology system and the effectiveness of various positioning algorithms.

[0180] The applicant of the present invention has made a detailed explanation and description of the implementation examples of the present invention in conjunction with the drawings in the specification. However, those skilled in the art should understand that the above implementation examples are only preferred implementation schemes of the present invention, and the detailed description is only to help readers better understand the spirit of the present invention, but not to limit the scope of protection of the present invention. On the contrary, any improvements or modifications based on the inventive spirit of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for indoor and outdoor integrated positioning based on Beidou satellite navigation, characterized in that: The steps include: Step S1: Using 5G communication technology and Beidou satellite navigation system to locate the terminal receiver to obtain positioning data, where the positioning data includes time information and distance information; Step S2: Processing the positioning data using the Chan algorithm to obtain first position information data; Step S3: defining and using a weighting coefficient to adjust the first position information data to obtain final position information data; After the step of processing the positioning data using the Chan algorithm to obtain the first position information data, the following steps are further performed: Step S2.A: using the Taylor series expansion method to recursively calculate the first position information data using the positioning data to obtain the measurement error of the terminal receiver coordinates; Step S2.B: Compare the measurement error with a preset threshold value. If the measurement error is greater than the threshold value, return to step S2, use the first position information data as positioning data, and continue to use the Chan algorithm for processing; if the measurement error is less than the threshold value, go to step S3; The method of using 5G communication technology and Beidou satellite navigation system to locate the terminal receiver includes the following steps: Step S1.1: Synchronize the terminal receiver and BeiDou satellite; Step S1.2: Measure the distance between the Beidou satellite and the terminal receiver; Step S1.3: Find the Beidou satellite position and determine the number of terminal receivers receiving signals from the same Beidou satellite; Step S1.4: Multilateration positioning of the terminal receiver; The synchronization terminal receiver and the Beidou satellite are synchronized by using the FTSP time synchronization algorithm, specifically by unidirectionally broadcasting synchronization messages between the reference node and the node to be synchronized. The synchronization terminal receiver and Beidou satellite comprises the following steps: Step S1.1.1: Allocate a unique identification number to all nodes in the entire network as an identifier, and use the root node of the entire wireless sensor network as a reference node for time synchronization; Step S1.1.2: The root node marks its own synchronization information with a timestamp and sends it to all nodes to be synchronized within the communication range in a flooding manner. After receiving the synchronization information, the nodes to be synchronized parse the timestamp therein, calculate the clock offset, adjust the local time to the reference time, and complete the time synchronization; Step S1.1.3: All nodes to be synchronized refer to the root node and use themselves as reference nodes to broadcast synchronization messages within the communication range. The synchronization messages contain two timestamp information. All unsynchronized nodes complete their own time synchronization after receiving the timestamp information. The synchronized nodes determine the synchronization level according to the timestamp information. Step S1.1.4: Determine whether all nodes in the entire network have received the synchronization message. If not, go to step S1.1.

1. If yes, exit; The calculation formula of the weighting coefficient is as follows: Wherein, η is the weighting coefficient, n is the number of measurements, l is the number of reference terminal receivers, △R is the square of the difference between the reference terminal receiver positioning coordinate measurement value and the estimated value, and i is the number of the terminal receiver.

2. The indoor and outdoor integrated positioning method based on Beidou satellite navigation according to claim 1 is characterized in that: The positioning data is processed using the Chan algorithm, and the final calculation formula obtained is as follows: Where Z is the approximate solution of the TDOA covariance matrix, Ψ is the covariance matrix of the vector error, G is the distance difference matrix, h is the distance difference error matrix, T represents the transposed matrix, and a is the number of iterations.

3. The indoor and outdoor integrated positioning method based on Beidou satellite navigation according to claim 1 is characterized in that: The Taylor series expansion method is used to recursively calculate the first position information data using the positioning data to obtain the measurement error of the terminal receiver coordinates. The calculation formula is as follows: Among them, δ is the solution of the least squares vector error, Q is the covariance matrix of TDOA, △x is the measurement error between the i-th node position information and the first position information data in the x-axis direction, △y is the measurement error between the i-th node position information and the first position information data in the y-axis direction, i is the number of the terminal receiver, G is the distance difference matrix, h is the distance difference error matrix, and T represents the transposed matrix.

4. An indoor and outdoor integrated positioning system based on Beidou satellite navigation, characterized in that: include: A positioning data acquisition module, a first position information data acquisition module and a final position information data acquisition module, each module being connected in sequence; The positioning data acquisition module is used to use 5G communication technology and Beidou satellite navigation system to locate the terminal receiver and obtain positioning data, wherein the positioning data includes time information and distance information; The first location information data acquisition module is used to process the positioning data using a Chan algorithm to obtain first location information data; The final position information data acquisition module is used to define and use a weighting coefficient to adjust the first position information data to obtain the final position information data; After the step of processing the positioning data using the Chan algorithm to obtain the first position information data, the following steps are further performed: Step S2.A: using the Taylor series expansion method to recursively calculate the first position information data using the positioning data to obtain the measurement error of the terminal receiver coordinates; Step S2.B: Compare the measurement error with a preset threshold value. If the measurement error is greater than the threshold value, return to step S2, use the first position information data as positioning data, and continue to use the Chan algorithm for processing; if the measurement error is less than the threshold value, go to step S3; The method of using 5G communication technology and Beidou satellite navigation system to locate the terminal receiver includes the following steps: Step S1.1: Synchronize the terminal receiver and BeiDou satellite; Step S1.2: Measure the distance between the Beidou satellite and the terminal receiver; Step S1.3: Find the Beidou satellite position and determine the number of terminal receivers receiving signals from the same Beidou satellite; Step S1.4: Multilateration positioning of the terminal receiver; The synchronization terminal receiver and the Beidou satellite are synchronized by using the FTSP time synchronization algorithm, specifically by unidirectionally broadcasting synchronization messages between the reference node and the node to be synchronized. The synchronization terminal receiver and Beidou satellite comprises the following steps: Step S1.1.1: Allocate a unique identification number to all nodes in the entire network as an identifier, and use the root node of the entire wireless sensor network as a reference node for time synchronization; Step S1.1.2: The root node marks its own synchronization information with a timestamp and sends it to all nodes to be synchronized within the communication range in a flooding manner. After receiving the synchronization information, the nodes to be synchronized parse the timestamp therein, calculate the clock offset, adjust the local time to the reference time, and complete the time synchronization; Step S1.1.3: All nodes to be synchronized refer to the root node and use themselves as reference nodes to broadcast synchronization messages within the communication range. The synchronization messages contain two timestamp information. All unsynchronized nodes complete their own time synchronization after receiving the timestamp information. The synchronized nodes determine the synchronization level according to the timestamp information. Step S1.1.4: Determine whether all nodes in the entire network have received the synchronization message. If not, go to step S1.1.

1. If yes, exit; The calculation formula of the weighting coefficient is as follows: Wherein, η is the weighting coefficient, n is the number of measurements, l is the number of reference terminal receivers, △R is the square of the difference between the reference terminal receiver positioning coordinate measurement value and the estimated value, and i is the number of the terminal receiver.

5. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions, which, when executed on a computer, enable the computer to execute the indoor and outdoor integrated positioning method based on Beidou satellite navigation as described in any one of claims 1 to 3.

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