Railway station yard positioning system and method based on beidou positioning

Abstract

The application provides a railway station yard positioning system and method based on Beidou positioning, and relates to the technical field of railway station yard positioning, and comprises at least one base station receiver, a mobile receiver and a correction receiver; wherein the base station receiver is arranged at a preset control point, and the mobile receiver and the correction receiver are arranged on a positioned target object; the base station receiver is used for receiving a first carrier phase of a Beidou navigation satellite system and sending the first carrier phase to the correction receiver; the mobile receiver is used for receiving a second carrier phase of the Beidou navigation satellite system and sending the second carrier phase to the correction receiver; and the correction receiver is used for generating differential correction information based on the first carrier phase and correcting the second carrier phase based on the differential correction information to obtain target position information of the positioned target object. The application improves the stability and accuracy of positioning in a complex scene of a railway station yard.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of railway station positioning, and in particular to a railway station positioning system and method based on Beidou positioning. BACKGROUND

[0002] At present, Beidou RTK (Real Time Kinematic, real-time dynamic carrier phase difference technology) high-precision positioning technology has been widely used in the market. This technology receives satellite signals through the Beidou satellite navigation system and combines the RTK differential positioning principle to achieve centimeter-level positioning accuracy. Specifically, the Beidou RTK system includes two parts: a reference station and a mobile station. The reference station receives Beidou satellite signals and calculates the errors of the satellite signals, and then sends these error information to the mobile station through the data link. After the mobile station receives the error information, it corrects the satellite signals it receives, thereby achieving high-precision positioning. However, the existing RTK differential positioning technology cannot stably and accurately position in the complex environment of a railway station. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a railway station positioning system and method based on Beidou positioning to improve the stability and accuracy of positioning in complex scenarios of a railway station.

[0004] To achieve the above purpose, the technical solution adopted by the present application is as follows:

[0005] In a first aspect, the present application provides a railway station positioning system based on Beidou positioning, comprising: at least one base station receiver, a mobile receiver and a correction receiver; wherein the base station receiver is arranged at a predetermined control point, and the mobile receiver and the correction receiver are arranged on a target object to be positioned; the base station receiver is used to receive the first carrier phase of the Beidou navigation satellite system and send it to the correction receiver; the mobile receiver is used to receive the second carrier phase of the Beidou navigation satellite system and send it to the correction receiver; the correction receiver is used to generate differential correction information based on the first carrier phase and correct the second carrier phase based on the differential correction information to obtain the target position information of the target object to be positioned.

[0006] Optionally, the correction receiver is specifically configured to: determine the position information of the base station receiver based on the first carrier phase, and determine the differential correction information based on the position information of the base station receiver and the position information of the control point; determine the position information of the target object to be positioned based on the second carrier phase, and correct the position information of the target object to be positioned based on the differential correction information to obtain the target position information of the target object to be positioned.

[0007] Optionally, the base station receiver further comprises a differential source configured to send the differential correction information to the correction receiver via the NTRIP protocol.

[0008] Optionally, the correction receiver comprises a first correction unit configured to determine the coordinate information of the target object based on the target position information of the target object by using a position matching algorithm, and a second correction unit configured to correct the target position information of the target object by using a positioning latitude and longitude information error path matching algorithm.

[0009] Optionally, the first correction unit is specifically configured to collect latitude and longitude information of a road network in a railway station yard, and create a coordinate system set based on the latitude and longitude information; compare the target position information of the target object with coordinate points in the coordinate system set to determine a railway track corresponding to the target object; calculate a foot point of the target object to the railway track based on latitude and longitude information of the railway track, and obtain the coordinate information of the target object based on the foot point.

[0010] Optionally, the second correction unit is specifically configured to correct the target position information of the target object based on a moving speed of the target object or a position difference value of the target position information of the target object between adjacent sampling points; or correct the target position information of the target object based on a plurality of historical position information of the target object and a moving direction of the target object; or calculate a shortest distance from the target position information of the target object to the railway track, and correct the target position information of the target object based on the shortest distance.

[0011] Optionally, the correction receiver is further configured to calculate a parked vehicle position based on the target position information of the target object and the received shunting operation information.

[0012] In a second aspect, the present application provides a railway station yard positioning method based on Beidou positioning, which is applied to the railway station yard positioning system based on Beidou positioning provided in any of the first aspect, and comprises the following steps: receiving, by a base station receiver, a first carrier phase of a Beidou navigation satellite system, and sending the first carrier phase to a correction receiver; receiving, by a mobile receiver, a second carrier phase of the Beidou navigation satellite system, and sending the second carrier phase to the correction receiver; generating, by the correction receiver, differential correction information based on the first carrier phase, and correcting the second carrier phase based on the differential correction information to obtain target position information of a target object.

[0013] In a third aspect, the present application provides an electronic device comprising a processor and a memory, wherein the memory stores computer executable instructions capable of being executed by the processor, and the processor executes the computer executable instructions to implement the steps of the method provided in any of the second aspect.

[0014] In a fourth aspect, the present application provides a computer readable storage medium, and the computer readable storage medium stores a computer program, and the computer program is run by a processor to execute the steps of the method of any one of the above-mentioned second aspect.

[0015] The present application has the following beneficial effects:

[0016] The above-mentioned railway station positioning system and method based on Beidou positioning provided by the present application comprise: at least one base station receiver, a mobile receiver and a correction receiver; wherein the base station receiver is arranged at a preset control point, and the mobile receiver and the correction receiver are arranged on a target object to be positioned; the base station receiver is used for receiving a first carrier phase of a Beidou navigation satellite system and sending the first carrier phase to the correction receiver; the mobile receiver is used for receiving a second carrier phase of the Beidou navigation satellite system and sending the second carrier phase to the correction receiver; and the correction receiver is used for generating differential correction information based on the first carrier phase and correcting the second carrier phase based on the differential correction information to obtain target position information of the target object to be positioned. The positioning system sends the data collected by the base station receiver and the mobile receiver to the correction receiver, and the correction receiver analyzes the data to obtain high-precision target position information of the target object to be positioned, thereby ensuring high-precision positioning of less than 0.5 m in a complex railway environment and improving the stability and accuracy of positioning in a complex railway station environment.

[0017] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and achieved by the structure particularly pointed out in the description, claims and drawings.

[0018] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the following will be described in detail in combination with the preferred embodiments and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0020] Figure 1 A structure schematic diagram of a railway station positioning system based on Beidou positioning provided by an embodiment of the present application is shown in the figure.

[0021] Figure 2A schematic diagram of a position positioning algorithm provided for an embodiment of the present application;

[0022] Figure 3 A flow chart of a railway station positioning method based on Beidou positioning provided for an embodiment of the present application;

[0023] Figure 4 A structural schematic diagram of an electronic device provided for an embodiment of the present application. DETAILED DESCRIPTION

[0024] To make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0025] At present, the existing RTK differential positioning technology cannot stably and accurately position in the complex environment of a railway station. There are mainly the following problems;

[0026] 1. High-voltage interference (complex electromagnetic environment)

[0027] The high-voltage transmission line and the electrified railway catenary (25kV alternating current) around the railway station will produce wideband electromagnetic radiation, and the frequency range may cover the Beidou satellite L band (1.2-1.6GHz), which causes the receiver front-end circuit to be saturated or the signal-to-noise ratio to be deteriorated, and mainly affects as follows.

[0028] Carrier phase observation value jump: electromagnetic noise overwhelms weak satellite signals, leading to frequent cycle slips, which destroys the continuous phase tracking required for RTK positioning.

[0029] Data link interruption: the electromagnetic interference of the data transmission radio or 4G / 5G differential signal transmission causes the packet loss rate of the communication between the reference station and the mobile station to rise.

[0030] 2. High building shielding (urban canyon effect)

[0031] The high-rise buildings (such as station buildings and commercial complexes) around the railway station form an "urban canyon", and when the satellite elevation angle is <30°, the signal is shielded, and when the number of visible satellites is <6, the RTK fixed solution fails. The reflective surfaces such as glass curtain walls and metal canopies cause the signal to be reflected multiple times to reach the receiver, and the pseudo-range measurement error can reach meters, and the carrier phase ambiguity resolution convergence time is prolonged. Temporary obstacles such as cranes and mobile devices in the station yard cause dynamic changes in signal shielding, which aggravates the positioning result jitter.

[0032] 3. Vehicle body (metal) shielding (near-field shielding effect)

[0033] The metal structure of the train compartment, freight container, etc. forms a Faraday cage effect, and the attenuation of the L-band signal can reach more than 20 dB, resulting in that the received power of the flow station antenna is lower than the capture threshold. The reflected signal of the metal surface is superimposed with the direct signal, causing the carrier phase interference phenomenon, especially the positioning error at the edge of the car body presents a spatial correlation distortion. When the station yard is shunted, the flow station installed on the roof can still be blocked laterally by the adjacent car body, resulting in the deterioration of the satellite geometry (DOP value).

[0034] 4、Dynamic multipath interference

[0035] The metal objects such as the train driving in the station yard and the mobile maintenance equipment form a time-varying reflection environment, resulting in the non-stationary characteristics of the multipath error, and the traditional Kalman filter is difficult to effectively suppress. The low-elevation reflection surface such as the station canopy and the track ballast aggravates the ground multipath interference of the L1 / L2 signal, and introduces the decimeter-level error in the low-elevation satellite (<15°) observation value.

[0036] 5、Complex electromagnetic environment

[0037] The wireless dispatching system (400 MHz), Wi-Fi (2.4 GHz), radar and other devices around the station may produce in-band spurious radiation, resulting in the decrease of the signal-to-noise ratio of the receiver correlator output. The transient electromagnetic pulse generated by the power car pantograph offline discharge, relay switch, etc. causes the abnormal ADC sampling data, and the observation value appears an outlier (Outlier).

[0038] Based on this, the railway station yard positioning system and method based on Beidou positioning provided by the embodiment of the application can improve the stability and accuracy of positioning in the complex scene of the railway station yard.

[0039] In order to facilitate the understanding of the embodiment, first, a railway station yard positioning system based on Beidou positioning disclosed by the embodiment of the application is introduced in detail, referring to the structure schematic diagram of a railway station yard positioning system based on Beidou positioning shown in Figure 1 The system includes at least one base station receiver (i.e. reference station), mobile receiver and correction receiver; wherein the base station receiver is arranged at a preset control point, and the accurate position of the control point in the embodiment is known. The mobile receiver and the correction receiver are arranged on the target object to be positioned, which can be personnel or vehicles. The correction receiver can also be arranged on the server.

[0040] In the embodiments of the present application, at least one RTK can be selected as a base station receiver. When the base station receiver is close to the mobile receiver (distance < 20 km), the base station receiver can send the received satellite signals and other information to the mobile receiver in real time. The mobile receiver then performs difference operation on the received same satellite signals and other information and the information of the base station receiver, so as to realize centimeter-level (accuracy < 0.5 m) positioning accuracy. However, if the RTK is in an environment with few or poor quality satellite search (such as under a tree, a building, metal, glass, etc.), the fixing effect and positioning accuracy of the RTK will be affected to some extent. The principle of relative positioning is actually to assume that the errors received by the base station and the mobile station are the same. Therefore, the farther the distance between the two is, the worse the positioning accuracy can be.

[0041] Based on this, in the present application, the positioning coordinates and states of the mobile receiver and multiple base station receivers can be used to automatically communicate with the base station receiver with the best positioning state in the case that the positioning state is not good. Specifically, the differential connection method can be used for communication in the present application. This method generates an initial request data packet conforming to the NTRIP protocol (based on HTTP), which is used to initiate connection to the NTRIP server (such as the CORS reference station server). The core functions include: constructing the GET request of the HTTP1.0 protocol, declaring the NTRIP1.0.0 of the client type, setting the connection behavior to close after a single request, and configuring the address, port, account, password, and mounting point of the connected CORS server.

[0042] In specific implementation, the base station receiver is used to receive a first carrier phase of the Beidou navigation satellite system and send the first carrier phase to the correction receiver. Specifically, a differential base station is added on the ground, that is, the base station receiver. The base station receiver is deployed on a control point with a known accurate position, is responsible for receiving signals from the Beidou navigation satellite system, and transmits the received signals and related information (such as observation data) to the correction receiver.

[0043] The mobile receiver is used to receive a second carrier phase of the Beidou navigation satellite system and send the second carrier phase to the correction receiver. Specifically, the mobile receiver is installed on a target object to be positioned, also receives signals from the Beidou navigation satellite system, and transmits data to the correction receiver through radio signals.

[0044] The correction receiver is used to generate differential correction information based on the first carrier phase, and correct the second carrier phase based on the differential correction information to obtain target position information of the positioned target object. Specifically, the correction receiver (that is, the RTK positioning module) accurately calculates the position of the mobile receiver (that is, the target position information of the positioned target object) by analyzing the signals from the base station receiver and the mobile receiver.

[0045] In an embodiment, the correction receiver is specifically configured to: determine position information of the base station receiver based on the first carrier phase, and determine differential correction information based on the position information of the base station receiver and the position information of the control point; determine position information of the positioned target object based on the second carrier phase, and correct the position information of the positioned target object based on the differential correction information to obtain target position information of the positioned target object.

[0046] Specifically, the correction receiver can first determine the position information of the base station receiver according to the received first carrier phase, and then compare the position information with the actual position of the base station receiver (i.e. the position of the control point where the base station receiver is deployed). If the difference is small, the correction receiver can send a differential correction information (determined according to the calculated position of the base station receiver and the actual position of the base station receiver) to the mobile receiver, which uses the differential correction information to correct its position to obtain the target position information of the positioned target object, thereby achieving high-precision positioning. At the same time, the entire positioning process is completed within a few seconds, ensuring real-time high-precision positioning.

[0047] In the embodiment of the application, the base station receiver and the mobile receiver can obtain data by searching for satellites. The satellite data obtained by searching contains satellite precise orbit parameters (such as Kepler six elements) and clock correction, which are used to calculate the real-time position of the satellite (geocentric coordinate system XYZ). The time taken by the satellite signal to propagate to the base station receiver and the mobile receiver is multiplied by the propagation speed (default light speed) to obtain the distance (pseudo-range) between the satellite and the base station receiver and the mobile receiver containing errors. By establishing an equation based on the distance and the known coordinates (X, Y, Z) of each satellite, the current coordinates (X, Y, Z) of the base station receiver and the mobile receiver can be calculated. The more satellites searched, the more known quantities, and the higher the RTK positioning accuracy.

[0048] Further, the correction receiver uses carrier phase differential technology to eliminate common errors (such as satellite clock error and ionospheric delay) by processing the carrier phase of the Beidou satellite signal. The base station receiver and the mobile receiver synchronously observe the same group of satellites, and the positioning accuracy is improved from meter level to centimeter level through real-time differential calculation.

[0049] The above-mentioned railway station positioning system based on Beidou positioning provided by the application sends the data collected by the base station receiver and the mobile receiver to the correction receiver, and the correction receiver analyzes the data to obtain high-precision target position information of the positioned target object, thereby ensuring high-precision positioning of less than 0.5 m (accuracy <0.5 m) under complex railways, and improving the stability and accuracy of positioning in complex railway station scenarios.

[0050] Since the satellite signal is affected by ionosphere, troposphere, multipath effect and other factors during transmission, the accuracy of single RTK positioning is usually only about 5 meters, that is, single point solution. In order to improve the positioning accuracy of RTK, a differential source is introduced in the embodiment of the application, the differential correction information is sent to the correction receiver through the NTRIP protocol, and the relative positioning mode is used to eliminate the common unknown error.

[0051] In one embodiment, after the target position information of the positioned target object is calculated by the correction receiver, the target position information can be further corrected by using a position positioning algorithm, so as to further improve the positioning accuracy. The position positioning algorithm mainly includes a personnel and vehicle position matching algorithm and a positioning latitude and longitude information error path matching algorithm.

[0052] Therefore, the correction receiver comprises a first correction unit configured to determine coordinate information of the positioned target object by using a position matching algorithm based on the target position information of the positioned target object. The personnel and vehicle position matching algorithm creates a coordinate system set based on the collected latitude and longitude information, and obtains new coordinates by comparing coordinate points, calculating average latitude, calculating radian, and calculating the perpendicular distance from a point to a straight line.

[0053] In specific implementation, the first correction unit is specifically configured to: collect latitude and longitude information of a road network in a railway station yard, and create a coordinate system set based on the latitude and longitude information; compare the target position information of the positioned target object with coordinate points in the coordinate system set, and determine a railway track corresponding to the positioned target object; calculate a perpendicular foot point of the positioned target object to the railway track based on the latitude and longitude information of the railway track, and obtain coordinate information of the positioned target object based on the perpendicular foot point.

[0054] Specifically, as shown in FIG. 1, Figure 2 First, a coordinate system set is created based on the collected latitude and longitude information of the road network in the railway station yard. Then, the obtained latitude and longitude coordinate points (i.e., the target position information of the positioned target object) are input into the set, and each coordinate point is compared with other coordinate points in the set to determine the railway track corresponding to the positioned target object. Furthermore, the average latitude is calculated based on the fact that the radius of the earth is about 6371 km, and the radian corresponding to an angle is calculated. Finally, the perpendicular distance from a point to a straight line is calculated, so as to calculate new coordinates in meters.

[0055] In specific implementation, the personnel and vehicle position matching algorithm is specifically as follows:

[0056] Step 1, assuming x1, y1, x2, y2 are the latitude and longitude information of the railway track, then the corresponding calculation of the straight line equation of the railway track is as follows:

[0057] : Calculate the y coefficient of the straight line equation;

[0058] : Calculate the x coefficient of the straight line equation;

[0059] : Calculate the constant term of the straight line equation;

[0060] Where the foot is the foot projection point of the point (0, 0) to the straight line, then the coordinates of the foot are calculated according to the following formula:

[0061] : Calculate the x coordinate of the foot;

[0062] : Calculate the y coordinate of the foot.

[0063] The formula is derived from vector projection and simplified as: .

[0064] : Calculate the distance from the point (0, 0) to the straight line.

[0065] The following formula is a direct application of the point-to-line distance formula: , where (x0, y0) is the point (0, 0).

[0066] Step 2, set the initial minimum distance dis = 5.0 (threshold), greater than 5.0 by default as matching to the line.

[0067] Step 3, traverse all the tracks: outer loop i traverses each track gpsMap.get(i); inner loop j traverses each line segment of the track gpsMap.get(i).get(j) to gpsMap.get(i).get(j+1).

[0068] Step 4, according to step 1, calculate the shortest distance from the point to the straight line, if dis > 5.0, it means there is no track within 5 meters of the point, otherwise return the nearest track number.

[0069] Step 5, if the track number returned by the above method is valid, execute the following method, otherwise return 0 directly.

[0070] Step 6, get the start point p1 and end point p2 of the line segment of the matched railway track:

[0071] p1 = gps.get(mGuDao).get(0) (line segment start point).

[0072] p2 = gps.get(mGuDao).get(size - 1) (end point of the line segment).

[0073] Step 7, calculate the straight line equation of the matched railway track.

[0074] (y coefficient of the straight line equation).

[0075] (x coefficient of the straight line equation).

[0076] (constant term).

[0077] The straight line equation is as follows:

[0078]

[0079] Step 8, calculate the x coordinate of the foot of the point p (projection point), that is, the x coordinate of the perpendicular projection of the point p to the straight line according to the following formula:

[0080]

[0081] Step 9, calculate the normalized projection ratio r according to the following formula:

[0082]

[0083] The normalized projection ratio represents the relative position of the foot x on the line segment [x1, x2]:

[0084] If r = 0, the foot is at p2 (the end point); if r = 1, the foot is at p1 (the starting point); if 0 < r < 1, the foot is inside the line segment; if r < 0 or r > 1, the foot is outside the line segment.

[0085] The second correction unit is configured to correct the target position information of the positioned target object by using a positioning latitude and longitude information error path matching algorithm. The positioning latitude and longitude information error path matching algorithm sets a threshold to judge the positioning validity, optimizes the result by using electronic fence and precision check, and determines the best matching road section by multi-point calibration and considering the positioning error.

[0086] In specific implementation, the second correction unit is specifically configured to:

[0087] (1) correct the target position information of the positioned target object based on the moving speed of the positioned target object or the position difference of the target position information of the positioned target object between adjacent sampling points.

[0088] Specifically, the positioning validity can be determined by setting different distance and accuracy thresholds and combining the speed and position changes. In the cyclic calculation process, the electronic fence and accuracy checking mechanism are used to optimize the positioning result, so as to ensure that the positioning accuracy is high in both the moving and static states. If the positioned target object is static, the position difference of the target position information of the positioned target object between adjacent sampling points can be used to determine whether the positioning is reasonable. If the position difference exceeds the set threshold, it is determined that the positioning is unreasonable. If the positioned target object is moving, the position difference of the target position information of the positioned target object between adjacent sampling points is combined with the moving speed of the positioned target object to determine whether the positioning is reasonable. Similarly, if the deviation between the position difference and the moving distance exceeds the preset threshold, it is determined that the positioning is unreasonable.

[0089] (2) Correct the target position information of the positioned target object based on the plurality of historical position information of the positioned target object and the moving direction of the positioned target object.

[0090] Specifically, during the movement of the positioned target object, the historical direction matching degree can be considered, the influence of the moving route on the position can be estimated by recording a plurality of positioning points, and the final position can be corrected. Among them, if the moving direction of the third positioning point is different from the other four historical position information, it is determined that the point is unreasonable, and the positioning information of the point is filtered out.

[0091] (3) Calculate the shortest distance from the target position information of the positioned target object to the railway track, and correct the target position information of the positioned target object based on the shortest distance.

[0092] Specifically, considering the positioning error of the Beidou satellite positioning system, the received data positioning point may deviate. In the embodiment of the present application, the shortest distance from the collected information point (i.e. the target position information of the positioned target object) to the path (i.e. the corresponding railway track) can be calculated, and whether the projection point is on the road is considered to determine the best matching section. If the error is large, whether the positioning information is accurate is confirmed by the speed of the locomotive.

[0093] Specifically, the positioning latitude and longitude information error path matching algorithm is as follows:

[0094] 1. Threshold judgment of positioning validity

[0095] According to steps 1-5 of the personnel and locomotive position matching algorithm, the track result obtained according to the threshold range is obtained.

[0096] 2. Electronic fence filtering

[0097] Initialize the range of the electronic fence, load the electronic fence from the database or configuration file, such as adding a rectangular fence, and then check whether there is an electronic fence according to the positioning result, as shown below:

[0098] 3. Precision check optimization

[0099] Get the longitude of the current position (east-west position), valid range: -180 to 180 (inclusive), -180 represents 180° west longitude (west of the international date line), and 180 represents 180° east longitude (east of the international date line).

[0100] The check conditions include:

[0101] location.getLongitude()<-180, i.e. the longitude is less than -180 (invalid);

[0102] location.getLongitude()>180, i.e. the longitude is greater than 180 (invalid).

[0103] Get the latitude of the current position (north-south position), valid range: -90 to 90 (inclusive), -90 represents the South Pole, and 90 represents the North Pole.

[0104] The check conditions include:

[0105] location.getLatitude()<-90, i.e. the latitude is less than -90 (invalid);

[0106] location.getLatitude()>90, i.e. the latitude is greater than 90 (invalid).

[0107] 4. Multi-point calibration

[0108] Kalman filter and inertial navigation unit are used for short-time dead reckoning. Specifically, the above-mentioned system provided by the embodiments of the present application fuses multi-dimensional technology optimization, mainly including: first, the base station receiver is deployed at a known coordinate point, and provides error correction reference for the mobile receiver by broadcasting differential correction data (such as RTCM format) in real time; second, the mobile receiver receives original satellite observation data at the same time, and combines differential data to solve high-precision relative position. In this process, the use of dual-frequency or multi-frequency signals significantly suppresses the influence of ionospheric delay, and through adaptive filtering algorithm (such as Kalman filter), random errors caused by multipath effect and receiver noise can be effectively smoothed. For complex environments (such as urban canyons or railway tunnels), the embodiments of the present application can also perform short-time dead reckoning through an inertial navigation unit (IMU) to ensure positioning continuity.

[0109] The core idea of Kalman filter is to constantly make "prediction" (estimate the current value based on previous data) and "correction" (adjust the predicted value with sensor and measurement data), so that the error becomes smaller and smaller.

[0110] The prediction stage of Kalman filter is: = + .

[0111] For the predicted state, it can be represented as: .

[0112] A is the state transition matrix, which describes how the state changes from the previous time to the current time k (e.g. the effect of speed), the state transition matrix A can be understood as a "time advancer", which determines how the current state changes to the next time.

[0113] For example: represents: 1. new position = old position + speed × time, 2. speed remains unchanged.

[0114] B is the degree of influence of control input on state (control matrix), is the control input, which represents the external influence, such as acceleration, braking, direction adjustment, etc., if there is no external input, this part can be ignored.

[0115] The above is a process of predicting the position, which is defined in Kalman filter as: prediction stage (Prediction Step), but since the measurement data will be affected by noise, the following process is also included, which is called correction stage (Correction Step). It is represented as:

[0116]

[0117] Among them, is the measurement value, is the predicted value, is the Kalman gain, which determines how to take a compromise between prediction and measurement, which is equivalent to a weight: if the measurement value is very reliable (sensor error is small), then takes a larger value, and more believes the measurement value. If the measurement value noise is larger, then takes a smaller value, and more depends on the predicted value.

[0118] The measurement value and the state variable are positions, so a weighted average can be directly taken. But if the measurement is not position, but speed, you need to introduce observation matrix H.

[0119]

[0120] In some cases, the state variables are not just positions, but also include speed, acceleration, and other variables.

[0121] For example: However, the measurement device may only measure part of the information, and the measurement value is only the speed, which cannot be directly weighted and averaged, but the speed information needs to be extracted from the state variable. Then the H matrix is defined as: , (since the measurement value only contains speed, and the state variable contains both position and speed, the corresponding speed information in the state variable is extracted through the matrix HHH to ensure that the correction process only affects the speed and does not change the position), which is the role of the matrix H: only the measured part is corrected, and other state variables are not affected.

[0122] An inertial navigation unit (IMU) is a core sensor used to measure the motion state of an object, typically composed of an accelerometer, a gyroscope, and (optionally) a magnetometer. It calculates the current position, attitude, and velocity information by detecting the angular velocity and linear acceleration of the object, without relying on external reference signals (such as GPS), thus having an advantage in short time or obstructed environments. The specific implementation process of the inertial navigation unit (IMU) involves hardware measurement, data preprocessing, motion state calculation, and error compensation, etc. The following is its detailed workflow:

[0123] 1. Hardware Measurement

[0124] The core sensors of the IMU output raw data in real time, including: Accelerometer: measures three-axis linear acceleration (unit: m / s²), including gravity component. Gyroscope: measures three-axis angular velocity (unit: rad / s), reflecting the rotation rate of the object. Magnetometer (if available): measures three-axis magnetic field strength (unit: μT), used to correct the heading angle.

[0125] 2. Data Preprocessing

[0126] Raw data needs to be calibrated and filtered to reduce errors, including the following steps:

[0127] 2.1 Calibration

[0128] 2.1.1 Zero Offset Correction: Eliminate the static bias of the sensor (such as the gyroscope should output 0 when stationary).

[0129] 2.1.2 Scale Factor Correction: Adjust the proportionality coefficient of the sensor output to make it consistent with the actual physical quantity.

[0130] 2.1.3 Non-orthogonal correction: compensate for non-orthogonal errors between sensor axes (e.g. X / Y / Z axes not perfectly perpendicular).

[0131] 2.2 Filtering

[0132] 2.2.1 Low-pass filtering: remove high-frequency noise (e.g. mechanical vibrations).

[0133] 2.2.2 Temperature compensation: adjust sensor output based on temperature changes (temperature affects zero offset and scale factor).

[0134] 3. Pose integration

[0135] Calculate the object's attitude angles (Pitch, Roll, Yaw) from gyroscope and accelerometer data:

[0136] 3.1 Gyroscope integration:

[0137] Integrate angular velocity to get attitude angles:

[0138]

[0139] 3.2 Complementary filtering or Kalman filtering:

[0140] 3.2.1 Fuse accelerometer and magnetometer data to correct gyroscope drift:

[0141] 3.2.2 Accelerometer estimates Pitch and Roll angles from gravity direction (effective when stationary).

[0142] 3.2.3 Magnetometer estimates Yaw angle from geomagnetic field (susceptible to interference, needs dynamic calibration).

[0143] 4. Position and velocity integration

[0144] Calculate displacement and velocity from accelerometer data, including:

[0145] 4.1 Gravity separation

[0146] Remove gravity component from accelerometer data (needs to know current attitude): .

[0147] Where R is the rotation matrix and g = [0, 0, 9.81]T is the gravity vector.

[0148] 4.2 Integration calculation

[0149] Integrate linear acceleration twice to get displacement:

[0150]

[0151] 5. Error compensation and fusion

[0152] The error of pure inertial navigation will grow over time and needs to be suppressed by the following methods:

[0153] 5.1 Zero Speed ​​Correction (ZUPT): When an object is detected to be stationary (such as a foot IMU), the speed is forced to zero and the error is reset.

[0154] 5.2 Multi-Sensor Fusion

[0155] 5.2.1GNSS / IMU combination: GPS provides absolute position and corrects IMU drift.

[0156] 5.2.2 Visual Inertial Navigation (VIO): The camera provides relative motion constraints.

[0157] 5.3 Kalman filter: Dynamically estimate and compensate for sensor errors (such as zero bias and scale factor).

[0158] 6. Output navigation parameters

[0159] The final output is 6-DoF information, including:

[0160] Attitude angles: Pitch, Roll, Yaw.

[0161] Speed: Three-axis speed.

[0162] Position: three-axis coordinates (the initial position must be known).

[0163] In one embodiment, the correction receiver is further configured to calculate the position of the parked vehicle based on the target position information of the located target object and the received shunting operation information.

[0164] In specific implementations, the position of the parked vehicle can be calculated based on satellite positioning and shunting operation information. Based on the operation signaling link, the track unhooking position (the position of the personnel's handheld device, i.e., the location of the located target object) is collected in real time, along with information about the current vehicle and the azimuth of the parked vehicle (clockwise angle relative to north). Based on this, the ground control center can calculate the accurate starting and ending positions of the parked vehicle. The initial position is the collected position of the located target object. The calculation of the ending position (i.e., the second point) includes:

[0165] Calculate the longitude of the second point, that is, the distance of horizontal translation ( ) divided by the current latitude section perimeter ( ), and then multiply it by 360 degrees to get the number of degrees of horizontal translation, and add lon1 (the longitude of the initial position) to get the value of the longitude lon2 of the second point.

[0166]

[0167] Calculate the latitude of the second point, that is, the distance of vertical translation (lat1 - lat0) divided by the longitudinal circumference of the earth, and then multiplied by 360 degrees, that is, how many degrees of longitudinal translation, plus lat1 (the latitude of the initial position), that is, the value of the latitude lat2 of the second point.

[0168] wherein,

[0169] is the length of the parked vehicle, d is the azimuth angle of the parked vehicle. α As a core means to improve the accuracy of satellite navigation and positioning, the core idea of Beidou differential technology is to eliminate the common errors in the satellite signal propagation process through data sharing and collaborative processing between multiple receivers. This technology relies on the synchronous observation of reference stations and mobile stations, and uses the spatial correlation of the signals received by the two to model and offset systematic biases such as ionospheric delay, tropospheric delay, and satellite orbit error. In the Real-Time Kinematic (RTK) mode, through carrier phase differential processing and integer ambiguity fixing algorithms, the Beidou positioning accuracy can be improved from the meter level of single point positioning to the centimeter level (the horizontal accuracy is usually better than 0.5 meters).

[0170] In the examples of the present application, the redundant observations and data screening in the post-processing stage further improve the reliability. Multiple independent observations are made at key measurement points, and gross errors are removed through statistical analysis methods, and then the internal consistency of the overall measurement results is optimized by combining with network adjustment technology. This dual protection mechanism of "real-time difference + post-processing" enables the Beidou RTK system to stably output centimeter-level positioning results in scenes with strict accuracy requirements such as engineering surveying, precision agriculture, and rail transportation, while meeting the dual demands of real-time and reliability.

[0171] The above-mentioned positioning system provided by the embodiment of the present application selects the RTK positioning module as the base station receiver and the mobile receiver, which has the characteristics of low power consumption, miniaturization and integration. Based on advanced process design, the BDS SoC design of miniaturization and radio frequency baseband integration and low power consumption is realized. (2) Support parallel acquisition and tracking technology of Beidou No. 3, support BDS: B1I, B1C, B2a,

[0172] . Strong real-time anti-interference capability, built-in wide / narrow band anti-interference technology, can detect and remove wide / narrow band interference in real time, and can resist total interference power not less than -75dBm; support ABDS; support multiple positioning modes: support single point positioning of dual-frequency BDS and RTK positioning of dual-frequency BDS. The main technical indexes are shown in Table 1.

[0173] Table 1 RTK positioning module technical indexes​

[0174]

[0175] For the foregoing embodiments of the Beidou positioning-based railway station positioning system, the embodiments of the present application also provide a Beidou positioning-based railway station positioning method, referring to Figure 3 The flowchart of the Beidou positioning-based railway station positioning method is shown in the figure, which shows that the method mainly includes the following steps S301 to S303:

[0176] Step S301: receiving the first carrier phase of the Beidou navigation satellite system through the base station receiver, and sending the first carrier phase to the correction receiver.

[0177] Step S302: receiving the second carrier phase of the Beidou navigation satellite system through the mobile receiver, and sending the second carrier phase to the correction receiver.

[0178] Step S303: generating differential correction information based on the first carrier phase through the correction receiver, and correcting the second carrier phase based on the differential correction information to obtain the target position information of the positioned target object.

[0179] The above-mentioned Beidou positioning-based railway station positioning method provided by the embodiments of the present application sends the data collected by the base station receiver and the mobile receiver to the correction receiver, and the correction receiver analyzes the data to obtain high-precision target position information of the positioned target object, thereby ensuring high-precision positioning of centimeter level (precision <0.5m) under complex railway conditions, and improving the stability and accuracy of positioning in complex railway station scenes.

[0180] It should be noted that the method provided by the embodiments of the present application has the same implementation principle and technical effects as the foregoing system embodiments. For brevity, the method embodiment part is not mentioned, and the corresponding content in the foregoing system embodiment can be referred to. The specific numerical values provided in the embodiments of the present application are only exemplary and are not limited herein.

[0181] The embodiments of the present application also provide an electronic device, specifically, the electronic device includes a processor and a storage device; the storage device stores a computer program, and the computer program executes the method described in any one of the above embodiments when executed by the processor.

[0182] Figure 4 The structure diagram of an electronic device provided by the embodiments of the present application is shown in the figure, and the electronic device 100 includes a processor 40, a memory 41, a bus 42 and a communication interface 43, the processor 40, the communication interface 43 and the memory 41 are connected through the bus 42; the processor 40 is used to execute the executable modules stored in the memory 41, such as computer programs.

[0183] The memory 41 can include a high-speed random access memory (RAM), and can also include a non-volatile memory, such as at least one disk memory. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 43 (which can be wired or wireless), and the Internet, a wide area network, a local area network, a metropolitan area network, etc. can be used.

[0184] The bus 42 can be an ISA bus, a PCI bus, an EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 4 Only one bidirectional arrow is used in the figure, but it does not mean that there is only one bus or only one type of bus.

[0185] The memory 41 is used to store programs, and the processor 40 executes the programs after receiving execution instructions. The method executed by the device defined by the flow process disclosed in any of the embodiments of the present application can be applied to the processor 40 or implemented by the processor 40.

[0186] The processor 40 can be an integrated circuit chip with signal processing capability. In implementation, each step of the above method can be completed by integrated logic circuit of hardware in the processor 40 or by instructions in the form of software. The processor 40 described above can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. Each method, step and logic block diagram disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as a hardware code processor for execution, or a combination of hardware and software modules in the code processor for execution. The software module can be located in a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium in the art. The storage medium is located in the memory 41, and the processor 40 reads the information in the memory 41, and combines the hardware to complete the steps of the above method.

[0187] The computer program product of the readable storage medium provided by the embodiments of the present application comprises a computer readable storage medium storing program codes, and the program codes comprise instructions for executing the method described in the foregoing method embodiments. For specific implementation, reference can be made to the foregoing method embodiments, which will not be described here.

[0188] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the present application that essentially contribute to the prior art or the parts of the technical solutions can be embodied in the form of software products. The computer software product is stored in a storage medium and includes instructions for making a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in the embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0189] Finally, it should be noted that: the above-described embodiments are only specific embodiments of the present application, which are used to illustrate the technical solutions of the present application, but not to limit them. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily think of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed by the present application, or make equivalent replacements to some of the technical features. The modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A railway station positioning system based on Beidou positioning, characterized in that: include: At least one base station receiver, a mobile receiver, and a correction receiver; wherein the base station receiver is set at a preset control point, and the mobile receiver and the correction receiver are set on the target object to be located; The base station receiver is used to receive a first carrier phase of the Beidou navigation satellite system and send the first carrier phase to the correction receiver; The mobile receiver is used to receive a second carrier phase of the Beidou navigation satellite system and send the second carrier phase to the correction receiver; The correction receiver is used to generate differential correction information based on the first carrier phase, and correct the second carrier phase based on the differential correction information to obtain target position information of the located target object; The correction receiver includes: a first correction unit, configured to determine coordinate information of the located target object using a position matching algorithm based on target position information of the located target object; A second correction unit is used to correct the target position information of the located target object by using a positioning latitude and longitude information error path matching algorithm; The first correction unit is specifically used to: collect the longitude and latitude information of the road network in the railway station, and create a coordinate system set based on the longitude and latitude information; compare the target position information of the located target object with the coordinate points in the coordinate system set to determine the railway track corresponding to the located target object; calculate the perpendicular point from the located target object to the railway track based on the longitude and latitude information of the railway track, and obtain the coordinate information of the located target object based on the perpendicular point.

2. The system according to claim 1, wherein: The correction receiver is specifically used for: determining position information of the base station receiver based on the first carrier phase, and determining differential correction information based on the position information of the base station receiver and the position information of the control point; The position information of the located target object is determined based on the second carrier phase, and the position information of the located target object is corrected based on the differential correction information to obtain the target position information of the located target object.

3. The system according to claim 2, characterized in that The base station receiver further includes: a differential source, configured to send the differential correction information to the correction receiver via the NTRIP protocol.

4. The system according to claim 1, wherein: The second correction unit is specifically configured to: Correcting the target position information of the located target object based on a moving speed of the located target object or a position difference of the target position information of the located target object between adjacent sampling points; Alternatively, based on a plurality of historical position information of the located target object and the moving direction of the located target object, the target position information of the located target object is corrected; Alternatively, the shortest distance from the target position information of the located target object to the railway track is calculated, and the target position information of the located target object is corrected based on the shortest distance.

5. The system according to claim 1, wherein: The correction receiver is further configured to: The position of the parked vehicle is calculated based on the target position information of the located target object and the received shunting operation information.

6. A railway station positioning method based on Beidou positioning, characterized in that: The Beidou-based railway station positioning system according to any one of claims 1 to 5 comprises: receiving a first carrier phase of the BeiDou navigation satellite system through a base station receiver, and sending the first carrier phase to a correction receiver; receiving a second carrier phase of the BeiDou navigation satellite system through a mobile receiver, and sending the second carrier phase to the correction receiver; The target position information of the located target object is obtained by generating differential correction information based on the first carrier phase by a correction receiver and correcting the second carrier phase based on the differential correction information.

7. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement the steps of the method according to claim 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to claim 6 are performed.

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