Railway yard positioning system and method based on Beidou positioning

Abstract

The invention provides a railway yard positioning system and method based on Beidou positioning, and relates to the technical field of railway yard positioning, and the system 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 the 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. According to the invention, the stability and accuracy of positioning in a complex scene of a railway yard are improved.

Description

Technical Field

[0001] The present invention 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 Art

[0002] Beidou RTK (Real Time Kinematic) high-precision positioning technology is currently widely used in the market. This technology uses the Beidou satellite navigation system to receive satellite signals and, in combination with RTK differential positioning principles, achieves centimeter-level positioning accuracy. Specifically, the Beidou RTK system consists of two components: a base station and a rover. The base station receives Beidou satellite signals, calculates satellite signal errors, and transmits this error information to the rover via a data link. The rover then corrects the received satellite signals, achieving high-precision positioning. However, existing RTK differential positioning technology cannot provide stable and accurate positioning in the complex environments of railway stations. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a railway station positioning system and method based on Beidou positioning, so as to improve the stability and accuracy of positioning in complex scenarios of railway stations.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows: In the first aspect, the present invention 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 preset control point, and the mobile receiver and the correction receiver are arranged on the target object to be positioned; 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 the target position information of the target object to be positioned.

[0005] Optionally, the correction receiver is specifically used 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 located target object based on the second carrier phase, and correct the position information of the located target object based on the differential correction information to obtain the target position information of the located target object.

[0006] Optionally, the base station receiver further includes: a differential source, configured to send differential correction information to the correction receiver via the NTRIP protocol.

[0007] Optionally, the correction receiver includes: a first correction unit, used to determine the coordinate information of the located target object based on the target position information of the located target object using a position matching algorithm; and a second correction unit, used to correct the target position information of the located target object using a positioning latitude and longitude information error path matching algorithm.

[0008] Optionally, the first correction unit is specifically used to: collect the latitude and longitude information of the road network in the railway station, and create a coordinate system set based on the latitude and longitude information; compare the target position information of the target object to be located with the coordinate points in the coordinate system set to determine the railway track corresponding to the target object to be located; calculate the perpendicular point of the target object to the railway track based on the latitude and longitude information of the railway track, and obtain the coordinate information of the target object to be located based on the perpendicular point.

[0009] Optionally, the second correction unit is specifically used to: correct the target position information of the located target object based on the moving speed of the located target object or the position difference of the target position information of the located target object between adjacent sampling points; or, correct the target position information of the located target object based on multiple historical position information of the located target object and the moving direction of the located target object; or, calculate the shortest distance from the target position information of the located target object to the railway track, and correct the target position information of the located target object based on the shortest distance.

[0010] Optionally, the correction receiver is further used 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.

[0011] In the second aspect, the present invention provides a railway station positioning method based on Beidou positioning, which is applied to any railway station positioning system based on Beidou positioning provided in the first aspect, including: receiving the 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 the second carrier phase of the Beidou navigation satellite system through a mobile receiver, and sending the second carrier phase to the correction receiver; 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 target object to be positioned.

[0012] In a third aspect, the present invention provides an electronic device comprising 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 any one of the methods provided in the second aspect above.

[0013] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program executes the steps of any one of the methods provided in the second aspect.

[0014] The present invention brings the following beneficial effects: The above-mentioned Beidou-based railway station positioning system and method provided by the present invention includes: 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 positioned; the base station receiver is used to receive the 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 the 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 the target position information of the positioned target object. The above-mentioned positioning system transmits 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 at the centimeter level (accuracy <0.5m) in complex railway conditions, and improving the stability and accuracy of positioning in complex scenarios of railway stations.

[0015] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purposes and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0016] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the preferred embodiments are specifically listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A schematic structural diagram of a railway station positioning system based on Beidou positioning provided by an embodiment of the present invention; Figure 2 A schematic diagram of a position positioning algorithm provided by an embodiment of the present invention; Figure 3 A flowchart of a railway station positioning method based on Beidou positioning provided by an embodiment of the present invention; Figure 4 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] Currently, the existing RTK differential positioning technology cannot provide stable and accurate positioning in the complex environment of railway stations. The main problems are as follows: 1. High-voltage electrical interference (complex electromagnetic environment) High-voltage transmission lines and electrified railway catenary systems (25kV AC) around railway stations generate broadband electromagnetic radiation, potentially covering the BeiDou satellite L-band (1.2-1.6GHz). This can lead to receiver front-end circuit saturation or signal-to-noise ratio degradation, with the following main impacts: Carrier phase observation value jumps: Electromagnetic noise overwhelms weak satellite signals, causing frequent cycle slips and disrupting the continuous phase tracking required for RTK positioning.

[0021] Data link interruption: The digital radio or 4G / 5G differential signal transmission is subject to electromagnetic interference, and the packet loss rate in communications between the base station and the rover increases.

[0022] 2. High building obstruction (urban canyon effect) High-rise buildings (such as station buildings and commercial complexes) around railway stations create "urban canyons." Signals are blocked when the satellite elevation angle is less than 30°, and RTK fixed solutions fail when the number of visible satellites is less than six. Reflective surfaces such as glass curtain walls and metal awnings cause signals to reflect multiple times before reaching the receiver, resulting in pseudorange measurement errors reaching meters and prolonged carrier phase ambiguity resolution convergence time. Temporary obstacles within the station yard, such as cranes and mobile equipment, cause dynamic signal obstruction, exacerbating positioning jitter.

[0023] 3. Vehicle (metal) shielding (near-field shielding effect) Metal structures such as train cars and freight containers create a Faraday cage effect, attenuating L-band signals by over 20dB, causing the rover antenna's received power to fall below the acquisition threshold. Signals reflected from metal surfaces superimpose on the direct signal, causing carrier phase interference. Positioning errors exhibit spatially correlated distortion, particularly at the edges of the vehicle. During yard shunting operations, even roof-mounted rovers can be laterally obscured by adjacent cars, degrading satellite geometry (DOP).

[0024] 4. Dynamic multipath interference Metal objects such as trains and mobile maintenance equipment within the station create a time-varying reflective environment, resulting in non-stationary multipath errors that are difficult to effectively suppress using traditional Kalman filters. Low-elevation-angle reflective surfaces such as platform canopies and track gravel exacerbate ground multipath interference in the L1 / L2 signals, introducing decimeter-level errors in observations from low-elevation-angle satellites (<15°).

[0025] 5. Complex electromagnetic environment Wireless dispatching systems (400 MHz), Wi-Fi (2.4 GHz), radar, and other equipment around stations can generate in-band spurious radiation, reducing the signal-to-noise ratio (SNR) of the receiver correlator output. Transient electromagnetic pulses generated by offline discharge of electric locomotive pantographs and relay switching can cause ADC sampling data anomalies and outliers in observed values.

[0026] Based on this, the embodiments of the present invention provide a railway station positioning system and method based on Beidou positioning, which can improve the stability and accuracy of positioning in complex scenarios of railway stations.

[0027] To facilitate understanding of this embodiment, firstly, a railway station positioning system based on Beidou positioning disclosed in an embodiment of the present invention is described in detail. Figure 1 The structural schematic diagram of a railway station positioning system based on Beidou positioning is shown, which illustrates that the system includes: at least one base station receiver (also known as a reference station), a mobile receiver and a correction receiver; wherein, the base station receiver is set at a preset control point, and the precise position of the control point in this embodiment is known, the mobile receiver and the correction receiver are set on the target object to be positioned, and the target object to be positioned can be a person or a vehicle, and the correction receiver can also be set on the server.

[0028] In this embodiment of the present invention, at least one RTK receiver can be selected as a base station. When the base station receiver is relatively close to the mobile receiver (less than 20 km), it can transmit received satellite signals and other information to the mobile receiver in real time. The mobile receiver then performs a difference calculation between the received satellite signals and other information and the information from the base station receiver, thereby achieving centimeter-level positioning accuracy (accuracy < 0.5 m). However, if the RTK environment has a small number of satellites to search or poor search quality (such as under trees, in buildings, on metal, or glass), this will affect the RTK's positioning effect and positioning accuracy to a certain extent. The principle of relative positioning actually assumes that the errors received by the base station and the mobile station are the same. Therefore, the greater the distance between the two, the lower the positioning accuracy may be.

[0029] Based on this, the present application can automatically communicate with the base station receiver with the best positioning status based on the positioning coordinates and positioning status of the mobile receiver and multiple base station receivers when the positioning status is not good. Specifically, the present application can use a differential connection method for communication. This method generates an initial request data packet that complies with the NTRIP protocol (based on HTTP) and is used to initiate a connection to the NTRIP server (such as a CORS base station server). The core functions include: constructing a GET request of the HTTP1.0 protocol, declaring the client type of NTRIP1.0.0, setting the connection behavior to close after a single request, and configuring the address, port, account, password, and mount point for connecting to the CORS server.

[0030] In practice, a base station receiver receives the first carrier phase of the BeiDou navigation satellite system and transmits it to a correction receiver. Specifically, a differential base station, or base station receiver, is deployed on the ground. Deployed at a control point with a known precise location, the base station receiver receives signals from the BeiDou navigation satellite system and transmits them, along with related information (such as observation data), to the correction receiver.

[0031] The mobile receiver is used to receive the second carrier phase of the BeiDou navigation satellite system and transmit the second carrier phase to the correction receiver. Specifically, the mobile receiver is mounted on the target object to be positioned, also receives signals from the BeiDou navigation satellite system, and transmits the data to the correction receiver via radio signals.

[0032] The correction receiver generates differential correction information based on the first carrier phase and corrects the second carrier phase based on this differential correction information to obtain the target position information of the located object. Specifically, the correction receiver (i.e., the RTK positioning module) analyzes signals from the base station receiver and the mobile receiver to accurately calculate the position of the mobile receiver (i.e., the target position information of the located object).

[0033] In one embodiment, the correction receiver is specifically used 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 located target object based on the second carrier phase, and correct the position information of the located target object based on the differential correction information to obtain the target position information of the located target object.

[0034] Specifically, the correction receiver can first determine the base station receiver's location information based on the received first carrier phase transmitted by the base station receiver. It then compares this location information with the base station receiver's actual location (i.e., the location of the control point where the base station receiver is deployed). If the difference is small, the correction receiver can send a differential correction signal (determined based on the calculated base station receiver position and the base station receiver's actual location) to the mobile receiver. The mobile receiver uses this differential correction signal to correct its position and obtain the target location information of the located target object, thereby achieving high-precision positioning. At the same time, the entire positioning process is completed within seconds, ensuring real-time high-precision positioning.

[0035] In this embodiment of the present invention, the base station receiver and mobile receiver can acquire data through satellite search. The searched satellite data contains precise satellite orbital parameters (such as Kepler's six elements) and clock corrections, which are used to calculate the satellite's real-time position (in the geocentric coordinate system XYZ). The time it takes for a known satellite signal to propagate to the base station receiver and mobile receiver is multiplied by the propagation speed (default is the speed of light) to obtain the distance (pseudorange) between the satellite and the base station receiver and mobile receiver, including errors. Using this distance and the known coordinates (X, Y, Z) of each satellite, a formula is established to calculate the current coordinates (X, Y, Z) of the base station receiver and mobile receiver. The more satellites discovered and the greater the known parameters, the higher the RTK positioning accuracy.

[0036] Furthermore, the correction receiver uses carrier phase differential technology to process the carrier phase of Beidou satellite signals and use the phase difference to eliminate common errors (such as satellite clock error and ionospheric delay). The base station receiver and mobile receiver simultaneously observe the same set of satellites, and through real-time differential calculation, positioning accuracy is improved from meters to centimeters.

[0037] The above-mentioned Beidou positioning-based railway station positioning system provided by the present invention sends the data collected by the base station receiver and the mobile receiver to the correction receiver, which analyzes the data to obtain high-precision target position information of the target object to be positioned, thereby ensuring high-precision positioning at the centimeter level (accuracy <0.5m) under complex railway conditions, and improving the stability and accuracy of positioning in complex scenarios of railway stations.

[0038] Because satellite signals are affected by various factors during propagation, such as the ionosphere, troposphere, and multipath, the accuracy of a single RTK positioning system is typically limited to approximately 5 meters, effectively achieving a single-point solution. To improve RTK positioning accuracy, the present invention introduces a differential source, sending differential correction information to a correction receiver via the NTRIP protocol. Relative positioning is then used to eliminate common unknown errors.

[0039] In one embodiment, after the calibration receiver calculates the target location information of the located object, a positioning algorithm can be used to further calibrate the target location information to further improve positioning accuracy. The positioning algorithm primarily includes a position matching algorithm for personnel and locomotives, and a path matching algorithm for positioning latitude and longitude information errors.

[0040] Based on this, the calibration receiver includes a first calibration unit, which uses a position matching algorithm to determine the coordinates of the located target object based on the target location information. The personnel and vehicle position matching algorithm creates a coordinate system based on the collected longitude and latitude information. The algorithm then compares coordinate points, calculates the average latitude, extrapolates arc angles, and calculates the perpendicular distance between the point and the line to obtain new coordinates.

[0041] During specific implementation, the first correction unit is specifically used to: collect the latitude and longitude information of the road network in the railway station, and create a coordinate system set based on the latitude and longitude information; compare the target position information of the target object to be located with the coordinate points in the coordinate system set to determine the railway track corresponding to the target object to be located; calculate the perpendicular point of the target object to the railway track based on the latitude and longitude information of the railway track, and obtain the coordinate information of the target object to be located based on the perpendicular point.

[0042] For details, see Figure 2 As shown in the figure, assume that point C is the point to be bound, i.e., the location of the target object, and AB are the surrounding road network points, i.e., the railway track points. First, a coordinate system set is created based on the collected longitude and latitude information of the road network in the railway station. The acquired longitude and latitude coordinates (i.e., the target location information of the target object) are then passed into this set. Each coordinate point is then repeatedly compared with the other coordinates in the set to determine the railway track corresponding to the target object. Furthermore, based on the Earth's radius of approximately 6371 km, the mean latitude is calculated, and the arc angle corresponding to each angle is deduced. Finally, the distance from the point to the foot of the perpendicular line is calculated to derive the new coordinates in meters.

[0043] In specific implementation, the personnel and locomotive position matching algorithm is as follows: Step 1: Assuming x1, y1, x2, and y2 are the latitude and longitude information of the railway track, calculate the equation of the straight line corresponding to the railway track according to the following formula: : Calculate the y coefficient of the straight line equation; : Calculate the x coefficient of the straight line equation; : Calculate the constant term of the straight line equation; The foot of the perpendicular is the projection point of the foot of the perpendicular from point (0,0) to the straight line. The coordinates of the foot of the perpendicular are calculated according to the following formula: : Calculate the x coordinate of the foot of the perpendicular; : Calculate the y-coordinate of the foot of the perpendicular.

[0044] The formula is derived from vector projection and is simplified to: .

[0045] : Calculate the distance from the point (0,0) to the straight line.

[0046] The following formula is a direct application of the point-to-line distance formula: , where (x0,y0) is the point (0,0).

[0047] Step 2: Set the initial minimum distance dis=5.0 (threshold). If it is greater than 5.0, it is considered to be matched to the line by default.

[0048] Step 3. Traverse all tracks: the outer loop i traverses each track gpsMap.get(i); the inner loop j traverses each line segment of the track from gpsMap.get(i).get(j) to gpsMap.get(i).get(j+1).

[0049] Step 4. Calculate the shortest distance from the point to the line according to step 1. If dis > 5.0, it means that no track is within 5 meters of the point. Otherwise, return the track number closest to the point.

[0050] Step 5. If the track number returned by the above method is valid, execute the following method; otherwise, return 0 directly.

[0051] Step 6: Get the starting point p1 and end point p2 of the matched railway track segment: p1=gps.get(mGuDao).get(0) (starting point of the line segment).

[0052] p2=gps.get(mGuDao).get(size-1) (end point of the line segment).

[0053] Step 7: Calculate the straight line equation of the matched railway track.

[0054] (y coefficient of the straight-line equation).

[0055] (x coefficient of the straight-line equation).

[0056] (constant term).

[0057] The form of the straight-line equation is as follows:

[0058] Step 8, calculate the x coordinate of the foot of the perpendicular (projection point) of point p, that is, the x coordinate of the perpendicular projection of point p onto the straight line, according to the following formula:

[0059] Step 9, calculate the normalized projection ratio r according to the following formula:

[0060] The normalized projection ratio represents the relative position of the foot of the perpendicular x on the line segment [x1, x2]: If r = 0, the foot of the perpendicular is at p2 (the end point); if r = 1, the foot of the perpendicular is at p1 (the starting point); if 0 < r < 1, the foot of the perpendicular is inside the line segment; if r < 0 or r > 1, the foot of the perpendicular is outside the line segment.

[0061] A second correction unit is used to correct the target position information of the target object to be located by using the positioning longitude and latitude information error path matching algorithm. The positioning longitude and latitude information error path matching algorithm sets a threshold to judge the positioning validity, utilizes the electronic fence and the accuracy inspection optimization result, and determines the best-matched road section through multi-point calibration and considering the positioning error.

[0062] In specific implementation, the second correction unit is specifically used for: (1) Correct the target position information of the target object to be located based on the moving speed of the target object to be located or the position difference of the target position information of the target object to be located between adjacent sampling points.

[0063] Specifically, the effectiveness of positioning can be determined by setting thresholds of different distances and accuracies, and combining changes in speed and position. During the cyclic calculation process, electronic fences and accuracy check mechanisms are used to optimize the positioning results to ensure that high positioning accuracy is maintained regardless of whether the object is moving or stationary. If the target object is stationary, the rationality of the positioning can be determined based on the position difference of the target position information of the target object between adjacent sampling points. If the position difference exceeds the set threshold, the positioning is determined to be unreasonable. If the target object is moving, the rationality of the positioning can be determined based on the position difference of the target position information of the target object between adjacent sampling points and the moving speed of the target object. Similarly, if the deviation between the position difference and its moving distance exceeds the preset threshold, the positioning is determined to be unreasonable.

[0064] (2) Correcting the target position information of the located target object based on the multiple historical position information of the located target object and the moving direction of the located target object.

[0065] Specifically, during the movement of the located object, the historical direction matching can be considered. By recording multiple positioning points, the impact of the movement route on the location can be estimated and the final position can be corrected. For example, if the movement direction of the third positioning point in five consecutive historical positions differs from the others, the point can be considered unreasonable and its positioning information can be filtered out.

[0066] (3) Calculate the shortest distance between the target position information of the located target object and the railway track, and correct the target position information of the located target object based on the shortest distance.

[0067] Specifically, given the positioning errors of the Beidou satellite positioning system, the received data location point may deviate. In this embodiment of the present invention, the optimal matching section can be determined by calculating the shortest distance from the collected information point (i.e., the target location information of the located object) to the path (i.e., the corresponding railway track), while also considering whether the projection point is on the road. If the error is large, the accuracy of the positioning information is confirmed by measuring the locomotive speed.

[0068] Specifically, the positioning latitude and longitude information error path matching algorithm is as follows: 1. Threshold value to determine positioning effectiveness According to steps 1 to 5 of the personnel and locomotive position matching algorithm, the track result obtained according to the threshold range is obtained.

[0069] 2. Electronic fence filtering Initialize the range of the geo-fence. You can load the geo-fence from the database or configuration file, such as adding a rectangular fence, and then check whether there is a geo-fence based on the positioning result, as shown below: 3. Accuracy check optimization Gets the longitude of the current location (east-west position). The valid range is: -180 to 180 (inclusive). -180 indicates 180° west longitude (west of the International Date Line), and 180 indicates 180° east longitude (east of the International Date Line).

[0070] Inspection conditions include: location.getLongitude()<-180, that is, the longitude is less than -180 (invalid); location.getLongitude()>180, that is, the longitude is greater than 180 (invalid).

[0071] Gets the latitude of the current location (the north-south position). The valid range is: -90 to 90 (inclusive), where -90 represents the South Pole and 90 represents the North Pole.

[0072] Inspection conditions include: location.getLatitude()<-90, that is, the latitude is less than -90 (invalid); location.getLatitude()>90, that is, the latitude is greater than 90 (invalid).

[0073] 4. Multi-point calibration Kalman filtering and an inertial navigation unit (IMU) are used for short-term dead reckoning. Specifically, the system provided by the present invention incorporates multi-dimensional technical optimizations, primarily including: first, base station receivers deployed at known coordinates broadcast real-time differential correction data (e.g., in RTCM format) to provide error correction references for mobile receivers; second, the mobile receivers receive raw satellite observation data and combine it with differential data to calculate high-precision relative position. In this process, the use of dual-frequency or multi-frequency signals significantly mitigates the effects of ionospheric delay, while adaptive filtering algorithms (e.g., Kalman filtering) effectively smooth random errors caused by multipath effects and receiver noise. For complex environments (such as urban canyons or railway tunnels), this embodiment can also utilize an inertial navigation unit (IMU) for short-term dead reckoning to ensure positioning continuity.

[0074] The core idea of ​​Kalman filtering is to continuously perform "prediction" (estimating the current value based on previous data) and "correction" (adjusting the predicted value using sensors and measurement data) to make the error smaller and smaller.

[0075] The prediction stage of Kalman filtering is: = + .

[0076] is the predicted state, which can be expressed as: .

[0077] A is the state transition matrix, which describes how the state changes from the previous moment to the next moment. Changes to the current moment k (such as the influence of speed), the state transfer matrix A can be understood as a "time advancer", which determines how the current state changes to the next moment.

[0078] For example: It means: 1. New position = old position + speed × time, 2. Speed ​​remains unchanged.

[0079] B is the influence of the control input on the 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.

[0080] The above is the process of predicting position, which is defined as the prediction step in Kalman filtering. However, since the measured data may be affected by noise, it also includes the next step, called the correction step. It can be expressed as:

[0081] in, is the measured value, is the predicted value, is the Kalman gain, which determines how to compromise between prediction and measurement, and is equivalent to a weight: if the measurement value is very reliable (the sensor error is small), then Take the larger value and trust the measured value more. If the measured value is noisy, then The smaller the value, the more dependent on the predicted value.

[0082] Measurements and state variables Since they are all positions, we can just do a weighted average. However, if we want to measure velocity instead of position, we need to introduce the measurement matrix H.

[0083]

[0084] In some cases, the state variables are not just position, but may also include velocity, acceleration, and other variables.

[0085] For example: However, the measuring device may only be able to measure part of the information. The measured value is only the speed, and it cannot be directly weighted averaged. Instead, the speed information must be extracted from the state variables. Then the H matrix is ​​defined as: , (Since the measured value only contains velocity, while the state variable contains both position and velocity, the corresponding velocity information in the state variable is extracted through the matrix HHH to ensure that the correction process only affects the velocity and does not change the position). This is the role of the matrix H: only the measured part is corrected without affecting other state variables.

[0086] An inertial measurement unit (IMU) is a core sensor used to measure an object's motion state, typically consisting of an accelerometer, gyroscope, and (optionally) magnetometer. It detects an object's angular velocity and linear acceleration, and, based on its initial state, infers its current position, attitude, and velocity. This eliminates the need for external reference signals (such as GPS), making it advantageous in short-duration or obstructed environments. The specific implementation of an IMU involves multiple steps, including hardware measurement, data preprocessing, motion state calculation, and error compensation. The following is a detailed workflow: 1. Hardware Measurement The core sensors of the IMU output raw data in real time, including: Accelerometer: measures the three-axis linear acceleration (unit: ), including the gravity component. Gyroscope: Measures three-axis angular velocity (unit: rad / srad / s), reflecting the object's rotation rate. Magnetometer (if included): Measures three-axis magnetic field strength (unit: μT) for heading correction.

[0087] 2. Data Preprocessing The raw data needs to be calibrated and filtered to reduce errors, including the following steps: 2.1 Calibration 2.1.1 Zero bias correction: Eliminate the static bias of the sensor (for example, the gyroscope should output 0 when it is stationary).

[0088] 2.1.2 Scale factor correction: Adjust the proportional coefficient of the sensor output to make it consistent with the actual physical quantity.

[0089] 2.1.3 Non-orthogonality correction: Compensate for non-orthogonality errors between sensor axes (such as X / Y / Z axes are not completely vertical).

[0090] 2.2 Filtering 2.2.1 Low-pass filtering: removes high-frequency noise (such as mechanical vibration).

[0091] 2.2.2 Temperature compensation: Adjust the sensor output according to temperature changes (temperature affects the zero bias and scale factor).

[0092] 3. Posture Settlement Calculate the object's attitude angle (pitch, roll, and yaw) using gyroscope and accelerometer data: 3.1 Gyroscope integration method: Integrating the angular velocity gives the attitude angle:

[0093] 3.2 Complementary filtering or Kalman filtering: 3.2.1 Fusion of accelerometer and magnetometer data to correct gyroscope drift: 3.2.2 Accelerometer estimates pitch and roll angles using the direction of gravity (valid when static).

[0094] 3.2.3 Magnetometer estimates the yaw angle through the Earth's magnetic field (susceptible to interference and requires dynamic calibration).

[0095] 4. Position and velocity settlement Inferring displacement and velocity from accelerometer data, including: 4.1 Gravity separation Remove the gravity component from the accelerometer data (need to know the current attitude): .

[0096] Where R is the rotation matrix and g=[0,0,9.81]T is the gravity vector.

[0097] 4.2 Points calculation The displacement is obtained by quadratically integrating the linear acceleration:

[0098] 5. Error compensation and fusion The error of pure inertial navigation will grow over time and needs to be suppressed by the following methods: 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.

[0099] 5.2 Multi-Sensor Fusion 5.2.1GNSS / IMU combination: GPS provides absolute position and corrects IMU drift.

[0100] 5.2.2 Visual Inertial Navigation (VIO): The camera provides relative motion constraints.

[0101] 5.3 Kalman filter: Dynamically estimate and compensate for sensor errors (such as zero bias and scale factor).

[0102] 6. Output navigation parameters The final output is 6-DoF information, including: Attitude angles: Pitch, Roll, Yaw.

[0103] Speed: Three-axis speed.

[0104] Position: three-axis coordinates (the initial position must be known).

[0105] 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.

[0106] 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 location (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: 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.

[0107]

[0108] Calculate the latitude of the second point, that is, the distance of vertical translation ( ) divided by the longitudinal circumference of the Earth, and then multiplied by 360 degrees, you can get the number of degrees of longitudinal translation, and add lat1 (the latitude of the initial position) to get the latitude of the second point, lat2.

[0109]

[0110] in, d is the length of the parked vehicle, α is the azimuth of the parked vehicle.

[0111] Beidou differential technology, a core means of improving satellite navigation positioning accuracy, relies on data sharing and collaborative processing among multiple receivers to eliminate common errors in satellite signal propagation. This technology relies on synchronized observations from a base station and a rover, exploiting the spatial correlation of their received signals to model and offset systematic biases such as ionospheric delay, tropospheric delay, and satellite orbit errors. In real-time kinematic (RTK) mode, carrier phase differential processing and an integer ambiguity fixation algorithm can improve Beidou positioning accuracy from the meter level for single-point positioning to the centimeter level (horizontal accuracy is typically better than 0.5 meters).

[0112] In this embodiment of the present invention, redundant observations and data screening during the post-processing phase further enhance reliability. Multiple independent observations are performed at key measurement points, gross errors are eliminated through statistical analysis, and network adjustment techniques are then combined to optimize the internal consistency of the overall measurement results. This dual guarantee mechanism of "real-time differencing + post-processing" enables the Beidou RTK system to stably output centimeter-level positioning results in demanding scenarios such as engineering surveying, precision agriculture, and rail transit, while meeting the dual requirements of real-time performance and reliability.

[0113] In the positioning system provided by the embodiment of the present invention, an RTK positioning module is selected as the base station receiver and the mobile receiver. The module has the characteristics of low power consumption, miniaturization, and integration. Based on advanced process design, a BDS SoC design with miniaturization, RF baseband integration, and low power consumption is realized. (2) Supports the parallel acquisition and tracking technology of BeiDou-3, and supports BDS: B1I, B1C, B2a, The GNSS 500 has strong real-time anti-interference capabilities, with built-in wideband and narrowband anti-interference technology enabling real-time detection and removal of wideband and narrowband interference, capable of withstanding total interference power levels of no less than -75dBm. It also supports ABDS and multiple positioning modes: single-point positioning with dual-frequency BDS and RTK positioning with dual-frequency BDS. Its main technical specifications are shown in Table 1.

[0114] Table 1 RTK positioning module technical indicators

[0115] Regarding the railway station positioning system based on Beidou positioning provided in the above embodiment, the embodiment of the present invention also provides a railway station positioning method based on Beidou positioning, see Figure 3 The flowchart of a railway station positioning method based on Beidou positioning is shown, which illustrates that the method mainly includes the following steps S301 to S303: Step S301: Receive a first carrier phase of the BeiDou navigation satellite system through a base station receiver, and send the first carrier phase to a correction receiver.

[0116] Step S302: Receive a second carrier phase of the BeiDou navigation satellite system through a mobile receiver, and send the second carrier phase to a correction receiver.

[0117] Step S303: generating differential correction information based on the first carrier phase by the correction receiver, and correcting the second carrier phase based on the differential correction information to obtain target position information of the located target object.

[0118] The above-mentioned railway station positioning method based on Beidou positioning provided by the embodiment of the present invention sends the data collected by the base station receiver and the mobile receiver to the correction receiver, and the correction receiver parses the data to obtain high-precision target position information of the target object to be positioned, thereby ensuring high-precision positioning at the centimeter level (accuracy <0.5m) under complex railway conditions, and improving the stability and accuracy of positioning in complex scenarios of railway stations.

[0119] It should be noted that the implementation principles and technical effects of the methods provided in the embodiments of the present invention are the same as those of the aforementioned system embodiments. For the sake of brevity, any details not mentioned in the method embodiments can be referred to the corresponding contents of the aforementioned system embodiments. The specific numerical values ​​provided in the implementation of the present invention are merely exemplary and are not intended to be limiting.

[0120] An embodiment of the present invention further provides an electronic device. Specifically, the electronic device includes a processor and a storage device. The storage device stores a computer program, and when the computer program is executed by the processor, it executes the method described in any one of the above embodiments.

[0121] Figure 4 This is a structural diagram of an electronic device provided in an embodiment of the present invention. 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 via the bus 42; the processor 40 is used to execute an executable module stored in the memory 41, such as a computer program.

[0122] Memory 41 may include high-speed random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage device. Communication between the system network element and at least one other network element is achieved through at least one communication interface 43 (which may be wired or wireless), and may utilize the Internet, a wide area network, a local area network, a metropolitan area network, or the like.

[0123] The bus 42 may be an ISA bus, a PCI bus, or an EISA bus. The bus may be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, Figure 4Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0124] Among them, the memory 41 is used to store programs, and the processor 40 executes the program after receiving the execution instruction. The method executed by the device for flow process definition disclosed in any embodiment of the above-mentioned embodiment of the present invention can be applied to the processor 40 or implemented by the processor 40.

[0125] Processor 40 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method may be completed by hardware integrated logic circuits or software instructions in processor 40. The above processor 40 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processing unit (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It may implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present invention. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in conjunction with the embodiments of the present invention may be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium well-known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory 41 , and the processor 40 reads the information in the memory 41 and completes the steps of the above method in combination with its hardware.

[0126] The computer program product of the readable storage medium provided in the embodiment of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the method described in the previous method embodiment. The specific implementation can be referred to the previous method embodiment and will not be repeated here.

[0127] If the functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0128] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-described embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. Such modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection 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 to correct the second carrier phase based on the differential correction information to obtain target position information of the located target object.

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 correction receiver comprises: a first correction unit, configured to determine coordinate information of the located target object by using a position matching algorithm based on the target position information of the located target object; The second correction unit is used to correct the target position information of the located target object by adopting a positioning latitude and longitude information error path matching algorithm.

5. The system according to claim 4, characterized in that The first correction unit is specifically configured to: Collecting the longitude and latitude information of the railway station network and creating a coordinate system set based on the longitude and latitude information; Comparing 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; A perpendicular point between the located target object and the railway track is calculated based on the longitude and latitude information of the railway track, and coordinate information of the located target object is obtained based on the perpendicular point.

6. The system according to claim 5, characterized in that 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.

7. The system according to claim 4, 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.

8. 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 7 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.

9. 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 8.

10. 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 8 are performed.

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