A method and system for positioning a rail transit train

Abstract

Embodiments of the present application disclose a method and system for positioning a rail transit train. Ultra-wideband (UWB) ground sensors are arranged on a rail line, and UWB vehicle-mounted sensors are arranged at set positions of the train. The UWB vehicle-mounted sensors include a UWB vehicle-mounted host and a UWB vehicle-mounted antenna that are connected to each other. The method includes: collecting distance information between the UWB ground sensors and the UWB vehicle-mounted antenna; calculating the spatial coordinates of the UWB vehicle-mounted antenna by using the distance information and the coordinates of the UWB ground sensors; and determining the positioning information of the train according to the spatial coordinates of the UWB vehicle-mounted antenna. Through the solution of this embodiment, the active positioning function of the mountain rail transit train is realized, and the positioning accuracy requirements are met.

Description

Technical Field

[0001] The embodiments of the present application relate to train positioning technology, and particularly to a rail transit train positioning method and system. Background Art

[0002] The conventional track operation speed limit of mountain rail transit is about 60 - 120 km / h, and the speed limit in the rack rail section is 10 - 30 km / h, which is similar to urban rail transit and conforms to the operation scenario of CBTC (CBTC, Communication Based on Train Control). Train positioning technology is one of the key technologies of CBTC. Real-time and accurate positioning information is the prerequisite for ensuring the safety and efficiency of trains. The powerful climbing ability of mountain rail transit makes the displacement change in the vertical direction very large when the train is running, which poses higher requirements for train positioning.

[0003] Common train positioning technologies include interrogator transponder technology, satellite positioning technology, track section positioning technology, mileage accumulation technology, inertial navigation technology, etc. Track section positioning technology locates according to track sections, with extremely poor accuracy and is completely inapplicable to the CBTC system. Interrogator transponder technology is a common train positioning technology in the CBTC system. However, due to the unique structure of the track and the train in mountain rail transit, it is difficult to find a metal-free area under the train chassis for installing the transponder receiving antenna, and it is also difficult to install transponders that meet European standards on the track. Satellite positioning technology has poor anti-interference ability in mountainous areas, and after entering the tunnel, additional differential base stations need to be installed. At the same time, the positioning accuracy is difficult to meet the requirements of precise parking in the station. Both mileage accumulation technology and inertial navigation technology have problems of cumulative errors in distance calculation.

[0004] In addition, except for satellite positioning technology, the above positioning technologies all have the situation that the train position is unknown after the train is initialized and powered on, and it takes a period of operation to achieve train positioning, which causes the train to run at a lower restricted speed and reduces the train operation efficiency.

[0005] Therefore, a train active positioning technology that can meet the active positioning requirements and accuracy of mountain rail transit trains is extremely important for the development of mountain rail transit. Summary of the Invention

[0006] The embodiments of the present application provide a rail transit train positioning method and system, which can realize the active positioning function of mountain rail transit trains and meet the positioning accuracy requirements.

[0007] An embodiment of the present application provides a method for positioning a rail transit train. Ultra-wideband (UWB) ground sensors are arranged on a track line, and UWB vehicle-mounted sensors are arranged at set positions of the train. The UWB vehicle-mounted sensors include a UWB vehicle-mounted host and a UWB vehicle-mounted antenna connected to each other. The method may include:

[0008] Collect distance information between the UWB ground sensor and the UWB vehicle-mounted antenna;

[0009] Calculate the spatial coordinates of the UWB vehicle-mounted antenna using the distance information and the coordinates of the UWB ground sensor;

[0010] Determine the positioning information of the train based on the spatial coordinates of the UWB vehicle-mounted antenna.

[0011] In an exemplary embodiment of the present application, the determining the positioning information of the train based on the spatial coordinates of the UWB vehicle-mounted antenna may include:

[0012] Taking the spatial coordinates of the UWB vehicle-mounted antenna as the positioning information of the train; or,

[0013] Calculate a first distance between the UWB vehicle-mounted antenna and a preset positioning reference point on the line according to the spatial coordinates of the UWB vehicle-mounted antenna; calculate a third distance between the head of the train and the positioning reference point according to the first distance and a second distance from the UWB vehicle-mounted antenna to the head of the train; calculate a distance from the head of the train to the starting point of the track section according to the third distance and the distance between the positioning reference point and the starting point of the track section; take the distance from the head of the train to the starting point of the track section as the positioning information of the train.

[0014] In an exemplary embodiment of the present application, the calculating the spatial coordinates of the UWB vehicle-mounted antenna using the distance information and the coordinates of the UWB ground sensor may include:

[0015] Taking the spatial coordinates of the UWB vehicle-mounted antenna as unknowns, and listing a system of equations about the unknowns according to the coordinates of the UWB ground sensor, the spatial coordinates of the UWB vehicle-mounted antenna, the distance information, and the distance formula between two points;

[0016] Solve the system of equations to obtain the spatial coordinates of the UWB vehicle-mounted antenna.

[0017] In an exemplary embodiment of the present application, before calculating the spatial coordinates of the UWB vehicle-mounted antenna using the distance information and the coordinates of the UWB ground sensor, the method may further include:

[0018] Obtain the line ramp angle where the UWB ground sensor is located and the train ramp angle where the UWB vehicle-mounted antenna is located;

[0019] Use the line ramp angle and the train ramp angle to correct the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna.

[0020] In an exemplary embodiment of the present application, the step of using the line ramp angle and the train ramp angle to correct the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna may include:

[0021] Calculate the included angle between the UWB ground sensor and the UWB vehicle-mounted antenna according to the line ramp angle and the train ramp angle;

[0022] Calculate the corrected distance information between the UWB ground sensor and the UWB vehicle-mounted antenna according to the included angle between the UWB ground sensor and the UWB vehicle-mounted antenna and the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna.

[0023] In an exemplary embodiment of the present application, the step of obtaining the line ramp angle where the UWB vehicle-mounted antenna is located may include:

[0024] Obtain the original wheel speeds measured by the speed sensors set on each wheel, and filter the original wheel speeds measured by the speed sensors to obtain the first wheel speeds;

[0025] Calculate the first wheel accelerations according to the first wheel speeds;

[0026] Obtain the original wheel accelerations measured by the acceleration sensors set on each wheel, and filter the original wheel accelerations measured by the acceleration sensors to obtain the second wheel accelerations;

[0027] Calculate the line ramp accelerations corresponding to each wheel according to the difference between the first wheel accelerations and the second wheel accelerations;

[0028] Determine the final line ramp acceleration according to whether the wheels are idling or skidding and the line ramp accelerations corresponding to each wheel;

[0029] Calculate the line ramp angle according to the final line ramp acceleration.

[0030] In an exemplary embodiment of the present application, the step of determining the final line ramp acceleration according to whether the wheels are idling or skidding and the line ramp accelerations corresponding to each wheel may include:

[0031] When neither of the two wheels slips or spins, calculate the average of the track ramp accelerations corresponding to the two wheels as the final track ramp acceleration;

[0032] When either of the wheels slips or spins, use the track ramp acceleration corresponding to the wheel that does not slip or spin as the final track ramp acceleration;

[0033] When both wheels slip or spin, use the data in the track database as the final track ramp acceleration.

[0034] In an exemplary embodiment of the present application, the method may further include:

[0035] Calculate the ranging error based on the ranging information of the axle speed sensor and the acceleration sensor, and the ranging information of the UWB ground sensor and the UWB vehicle-mounted sensor, and verify the positioning information of the train according to the magnitude of the ranging error.

[0036] In an exemplary embodiment of the present application, calculating the ranging error based on the ranging information of the axle speed sensor and the acceleration sensor, and the ranging information of the UWB ground sensor and the UWB vehicle-mounted sensor, and verifying the positioning information of the train according to the magnitude of the ranging error may include:

[0037] Estimate the wheel speed based on the acquisition data of the axle speed sensor and the acceleration sensor, and calculate the traveling distance of the train using the estimated vehicle speed;

[0038] Calculate the displacement of the train relative to the positioning reference point according to the traveling distance and a preset positioning reference point;

[0039] Calculate the distance between the train and the positioning reference point according to the positioning information of the train obtained by the UWB ground sensor and the UWB vehicle-mounted sensor;

[0040] Compare the calculated displacement with the distance to calculate the ranging error;

[0041] When the ranging error is greater than a preset difference threshold, confirm that the positioning information of the train is abnormal; when the ranging error is less than or equal to the preset difference threshold, confirm that the positioning information of the train is normal.

[0042] An embodiment of the present application also provides a positioning system for a mountain rail transit train, which may include: an ultra-wideband (UWB) ground sensor, a UWB vehicle-mounted sensor, a speed sensor, an acceleration sensor, a positioning reference point, a vehicle-mounted controller, and a computer-readable storage medium. The UWB vehicle-mounted sensor includes a UWB vehicle-mounted host and a UWB vehicle-mounted antenna connected to each other; instructions are stored in the computer-readable storage medium, and when the instructions are executed by the vehicle-mounted controller, the rail transit train positioning method described above is implemented.

[0043] In an exemplary embodiment of the present application, the UWB vehicle-mounted antenna is directly mounted on the UWB vehicle-mounted host or connected to the UWB vehicle-mounted host through wiring; the UWB vehicle-mounted antenna is vertically arranged along the forward direction of the train and mounted at the front end of the top of the train head;

[0044] The UWB vehicle-mounted antenna is mounted at the center line position of the roof;

[0045] The installation interval between multiple UWB vehicle-mounted antennas is greater than or equal to a preset interval threshold;

[0046] At least one set of UWB ground sensors is arranged on each ramp, and each set of UWB ground sensors is distributed on both sides of the track;

[0047] The vertical height difference between the UWB ground sensor and the UWB vehicle-mounted antenna is less than or equal to a preset height threshold;

[0048] The distance between multiple positioning reference points meets the requirements of a preset distance threshold.

[0049] Compared with the related art, an embodiment of the present application may include: collecting the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna; calculating the spatial coordinates of the UWB vehicle-mounted antenna by using the distance information and the coordinates of the UWB ground sensor; determining the positioning information of the train according to the spatial coordinates of the UWB vehicle-mounted antenna. Through the solution of this embodiment, the active positioning function of the mountain rail transit train is realized and the positioning accuracy requirements are met.

[0050] Other features and advantages of the present application will be described in the subsequent description, and part of them will become obvious from the description or be understood by implementing the present application. Other advantages of the present application can be realized and obtained through the solutions described in the description and the drawings. Description of the Drawings

[0051] The drawings are used to provide an understanding of the technical solutions of the present application, and constitute a part of the description. They are used together with the embodiments of the present application to explain the technical solutions of the present application and do not constitute a limitation to the technical solutions of the present application.

[0052] Figure 1 Flow chart of the rail transit train positioning method according to the embodiment of the present application;

[0053] Figure 2 Schematic diagram of the installation positions of the acceleration sensor and the speed sensor according to the embodiment of the present application;

[0054] Figure 3 Schematic diagram of the installation position of the UWB vehicle-mounted antenna according to the embodiment of the present application;

[0055] Figure 4 Schematic diagram of the UWB installation according to the embodiment of the present application;

[0056] Figure 5 Schematic diagram of the architecture of each module of the rail transit train positioning algorithm according to the embodiment of the present application;

[0057] Figure 6 Schematic diagram of the installation of the ground sensor according to the embodiment of the present application;

[0058] Figure 7 Flow chart of the method for obtaining the line ramp angle where the UWB vehicle-mounted antenna is located according to the embodiment of the present application;

[0059] Figure 8 Schematic diagram of ramp correction according to the embodiment of the present application;

[0060] Figure 9 Schematic diagram of the positions of three UWB ground sensors according to the embodiment of the present application;

[0061] Figure 10 Schematic diagram of curve positioning according to the embodiment of the present application;

[0062] Figure 11 Schematic diagram of the curve positioning embodiment according to the embodiment of the present application;

[0063] Figure 12 Block diagram of the composition of the rail transit train positioning system according to the embodiment of the present application. Detailed implementation manners

[0064] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it will be obvious to those of ordinary skill in the art that there can be more embodiments and implementation solutions within the scope covered by the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the detailed implementation manners, many other combination ways of the disclosed features are also possible. Unless specifically restricted, any feature or element of any embodiment can be combined with any other feature or element in any other embodiment, or can replace any other feature or element in any other embodiment.

[0065] This application includes and contemplates combinations with features and elements known to those of ordinary skill in the art. The disclosed embodiments, features, and elements of this application may also be combined with any conventional features or elements to form a unique inventive solution defined by the claims. Any feature or element of any embodiment may also be combined with features or elements from other inventive solutions to form another unique inventive solution defined by the claims. Accordingly, it should be understood that any feature shown and / or discussed in this application may be implemented alone or in any suitable combination. Accordingly, the embodiments are not limited except as defined by the appended claims and their equivalents. In addition, various modifications and changes may be made within the scope of the appended claims.

[0066] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a particular sequence of steps. However, to the extent that the method or process does not depend on the particular sequence of steps described herein, the method or process should not be limited to the recited particular sequence of steps. As will be understood by those of ordinary skill in the art, other sequences of steps are possible. Accordingly, the particular sequence of steps set forth in the specification should not be construed as a limitation on the claims. In addition, the claims directed to the method and / or process should not be limited to performing their steps in the order written, as those skilled in the art can readily understand that such order may vary and still remain within the spirit and scope of the embodiments of this application.

[0067] An embodiment of this application provides a method for positioning a rail transit train. Ultra-wideband (UWB) ground sensors are arranged on a rail line, and UWB vehicle-mounted sensors are arranged at set positions of the train. The UWB vehicle-mounted sensors include a UWB vehicle-mounted host and a UWB vehicle-mounted antenna connected to each other; as Figure 1 shown, the method may include steps S101 - S103:

[0068] S101. Collect distance information between the ultra-wideband (UWB) ground sensors and the UWB vehicle-mounted antenna;

[0069] S102. Calculate the spatial coordinates of the UWB vehicle-mounted antenna using the distance information and the coordinates of the UWB ground sensors;

[0070] S103. Determine the positioning information of the train based on the spatial coordinates of the UWB vehicle-mounted antenna.

[0071] UWB (Ultra Wide Band) is a carrierless communication technology that transmits data using non-sinusoidal narrow pulses in the nanosecond to picosecond range. By transmitting extremely low-power signals over a relatively wide spectrum, UWB can achieve data transmission rates ranging from several hundred Mbit / s (megabits per second) to several Gbit / s (gigabits per second) within a range of about 10 meters. UWB has many advantages such as strong anti-interference performance, high transmission rate, extremely wide bandwidth, low power consumption, and low transmit power.

[0072] Axle speed sensors are the most common train speed and distance measurement sensors. Its basic principle is to calculate the train speed and distance by calculating the rotation speed of the train wheels. Due to the creep phenomenon of the train wheels, axle speed sensors usually need to be assisted by other speed and distance measurement technical means that are not affected by the rotation speed of the train wheels, such as radar and acceleration sensors.

[0073] Acceleration sensors are sensors that measure the acceleration of the train in the traveling direction. The commonly used gravity servo acceleration sensors on trains have characteristics such as high sensitivity, high accuracy, and high safety.

[0074] Currently, the mainstream train speed, distance measurement, and positioning solution for CBTC systems is to use axle speed sensors and acceleration sensors to measure the train speed and distance, and then use interrogators to perform train positioning to eliminate the cumulative error of the train distance.

[0075] In the exemplary embodiment of the present application, based on the axle speed sensor and the acceleration sensor, a UWB ranging system is superimposed, and information fusion technology is used to achieve the active positioning function of mountain rail transit trains.

[0076] In the exemplary embodiment of the present application, the purpose of the embodiment of the present application is to meet the train active positioning technology for rail transit (such as mountain rail transit). The main contents include: the on-vehicle sensor configuration and installation plan for the mountain rail transit train active positioning technology, the ground sensor configuration and installation plan for the mountain rail transit train active positioning technology, and the algorithm for the mountain rail transit train active positioning technology.

[0077] In the exemplary embodiment of the present application, the configuration and installation plan of the on-vehicle sensors are introduced first.

[0078] In the exemplary embodiment of the present application, the on-vehicle sensors may include but are not limited to: speed sensors (such as axle speed sensors), acceleration sensors, and UWB on-vehicle sensors (which may include: UWB on-vehicle antennas and UWB on-vehicle hosts). The configured quantity of the on-vehicle sensors is shown in Table 1:

[0079] Table 1

[0080]

[0081]

[0082] In an exemplary embodiment of the present application, as shown in Table 1, the number of axle speed sensors can be 2, forming a hot standby redundancy configuration scheme; the number of acceleration sensors can be 3, forming a two-out-of-three configuration scheme; the UWB vehicle-mounted antennas correspond one-to-one with the UWB vehicle-mounted hosts, and the number of UWB vehicle-mounted antennas and UWB vehicle-mounted hosts can be 3 respectively, forming a two-out-of-three configuration scheme.

[0083] In an exemplary embodiment of the present application, the installation scheme of the axle speed sensor is introduced below.

[0084] In an exemplary embodiment of the present application, the measurement accuracy of the axle speed sensor is mainly affected by wheel creep in addition to the accuracy of the sensor itself. Therefore, in order to reduce the influence of wheel creep, the installation requirements of the axle speed sensor are as follows:

[0085] 1) It shall not be installed on the first wheel set in the forward direction of the train;

[0086] 2) Two axle speed sensors shall not be installed on the same wheel set of the train;

[0087] 3) Two axle speed sensors shall be installed on different axles of the same bogie as much as possible;

[0088] 4) Try not to install it on the power axle;

[0089] 5) It is preferably installed on the rolling axle.

[0090] In an exemplary embodiment of the present application, the installation scheme of the acceleration sensor is introduced below.

[0091] In an exemplary embodiment of the present application, the acceleration sensor is used to measure the acceleration of the train. Since the gravity servo type acceleration sensor is affected by gravity, therefore, in order to reduce the difference in the influence of gravity on the acceleration sensor and the accuracy of eliminating the gravity influence through the axle speed sensor, the installation requirements of the acceleration sensor are as follows:

[0092] 1) Three acceleration sensors are installed side by side along the forward direction of the train, as Figure 2 shown;

[0093] 2) Three acceleration sensors are installed as close as possible above the axle speed sensor.

[0094] In an exemplary embodiment of the present application, the installation scheme of the UWB vehicle-mounted antenna is introduced below.

[0095] In an exemplary embodiment of the present application, the UWB vehicle-mounted host has nothing to do with the measurement accuracy and can be installed near the vehicle-mounted VOBC (Vehicle OnBoard Controller, which is a component of CBTC). The installation of the UWB vehicle-mounted antenna is related to the measurement accuracy. To reduce problems such as measurement errors in the running distances of the inner and outer rails, the installation requirements for the UWB vehicle-mounted antenna can include the following:

[0096] 1) Try to arrange three UWB vehicle-mounted antennas vertically along the train's forward direction and install them at the very front of the vehicle head top;

[0097] 2) Try to install the three UWB vehicle-mounted antennas at the center line position of the vehicle roof;

[0098] 3) The installation interval between the three UWB vehicle-mounted antennas is not less than 50 cm.

[0099] In an exemplary embodiment of the present application, the installation scheme of the UWB vehicle-mounted antenna can be as Figure 3 shown.

[0100] In an exemplary embodiment of the present application, secondly, the configuration and installation scheme of the ground sensors are introduced.

[0101] In an exemplary embodiment of the present application, among the three sensors (speed sensor, acceleration sensor, and UWB sensor) used in the embodiments of the present application, only the UWB sensor is configured with ground equipment (i.e., UWB ground sensor) for wireless communication and positioning with the UWB vehicle-mounted antenna.

[0102] In an exemplary embodiment of the present application, in addition, benchmark points need to be arranged. As shown in Table 2, it is the ground equipment configuration table.

[0103] Table 2

[0104] Name Quantity Technical Conditions UWB Ground Sensor X Configure according to the configuration principle and the actual line length. Positioning Reference Point X Configure according to the configuration principle and the actual line length.

[0105] In an exemplary embodiment of the present application, the UWB ground sensor configuration scheme is introduced below.

[0106] In an exemplary embodiment of the present application, the UWB ranging method is calculated based on the time of light wave transmission between the UWB vehicle-mounted host and the UWB ground sensor through the UWB vehicle-mounted antenna. Therefore, a single UWB ground sensor can only measure the distance between this UWB ground sensor and the vehicle-mounted UWB vehicle-mounted antenna. Therefore, to achieve spatial positioning, at least 4 UWB ground sensors are required to achieve train positioning, and any 3 of these 4 UWB ground sensors must not be installed on the same straight line. Otherwise, the four UWB ground sensors can only form a plane and cannot form a space. However, if the UWB ground sensor and the UWB vehicle-mounted antenna are in the same plane, only 3 UWB ground sensors are required to achieve train positioning.

[0107] In an exemplary embodiment of the present application, to avoid the loss of the train positioning function due to the failure of 1 UWB ground device sensor, the embodiment of the present application adopts an N+1 redundant configuration scheme, that is, N UWB ground devices are used as a group to achieve the train positioning function, and 1 UWB ground device is reserved to prevent the loss of the positioning function caused by a single point of failure. Therefore, considering the cost of the entire system, the embodiment of the present application can ultimately adopt a 3+1 redundant configuration scheme.

[0108] In an exemplary embodiment of the present application, the installation scheme of the UWB ground sensor is introduced below.

[0109] In an exemplary embodiment of the present application, a 3+1 redundant configuration scheme can be adopted, that is, 3 UWB ground sensors are used to achieve train positioning. In this case, it is necessary to ensure that the UWB ground sensor and the UWB vehicle-mounted antenna are in the same plane. At the same time, considering the communication range between the UWB ground sensor and the UWB vehicle-mounted antenna, the installation requirements for the UWB ground sensor can be as follows:

[0110] 1) The UWB ground sensor group is arranged and installed in sections based on the ramp;

[0111] 2) When the slope difference between different ramp sections is not greater than 100‰, the ramp sections can be merged;

[0112] 3) The arrangement interval of the UWB ground sensor group in the merged ramp section is not greater than 500m;

[0113] 4) If a ramp section is in more than one track section, a group of UWB ground sensors needs to be arranged separately for each track section;

[0114] 5) In the ramp section where the radius of curvature is less than the preset radius threshold, the arrangement interval between the UWB ground sensor groups is not greater than 200m;

[0115] 6) The installation height difference between the UWB ground sensor and the UWB vehicle-mounted antenna when the train is in this section does not exceed 10cm;

[0116] 7) Each of the four UWB ground sensors included in each UWB ground sensor group is installed on both sides of the track, with two UWB ground sensors installed on each side.

[0117] 8) The installation interval between the two UWB ground sensors installed on the same side of the track in each UWB ground sensor group should divide the current ramp section into three equal parts.

[0118] 9) The UWB ground sensors installed on both sides of the track in each UWB ground sensor group should be installed on both sides of the track at the same position as much as possible.

[0119] In an exemplary embodiment of the present application, the UWB installation schematic diagram is as Figure 4 shown. Each UWB ground sensor group may include: UWB ground sensor 1, UWB ground sensor 2, UWB ground sensor 3, and UWB ground sensor 4.

[0120] In an exemplary embodiment of the present application, the following introduces the layout principle of the positioning reference points.

[0121] In an exemplary embodiment of the present application, the layout principle of the positioning reference points includes but is not limited to:

[0122] 1) In the straight section of the line section, the interval between the positioning reference points is not greater than 50 m.

[0123] 2) In the curved section of the line section, the interval between the positioning reference points is not greater than 5 m.

[0124] 3) In the straight section of the line platform area, the interval between the positioning reference points is not greater than 25 m.

[0125] 4) In the curved section of the line platform area, the interval between the positioning reference points is not greater than 3 m.

[0126] In an exemplary embodiment of the present application, the following details the train active positioning technology algorithm.

[0127] In an exemplary embodiment of the present application, the train active positioning technology algorithm can be completed by modules such as a data preprocessing module, a line ramp calculation module, a wheel spin and skid judgment module, and a train estimated position calculation module.

[0128] In an exemplary embodiment of the present application, the data preprocessing module may include two sub-modules: acceleration sensor data preprocessing and UWB sensor data preprocessing.

[0129] In an exemplary embodiment of the present application, the line ramp calculation module calculates the current ramp acceleration of the train according to the preprocessing results of the axle speed sensor and the acceleration sensor and combines the wheel spin and slide state through an algorithm, so as to obtain the ramp value.

[0130] In an exemplary embodiment of the present application, the wheel spin and slide judgment module uses the acceleration detection method and the speed difference detection method to judge wheel spin and slide.

[0131] In an exemplary embodiment of the present application, the train estimated position calculation module uses the trilateration positioning method to calculate the train estimated position.

[0132] In an exemplary embodiment of the present application, the algorithm module architecture can be as Figure 5 shown.

[0133] In an exemplary embodiment of the present application, the algorithm inputs of the train active positioning technology algorithm can include configuration inputs and real-time inputs:

[0134] 1) Configuration inputs refer to fixed data, including algorithm configuration parameters and line fixed data. As shown in Table 3, it is an example of configuration input information.

[0135] 2) Real-time input data are sensor input data. As shown in Table 4, it is an example of real-time input information.

[0136] Table 3

[0137]

[0138] Table 4

[0139]

[0140]

[0141] In an exemplary embodiment of the present application, the distances and IDs between the UWB vehicle-mounted sensors and the UWB ground sensors are more than one, and all UWB ground sensors within the effective reception range are included.

[0142] In an exemplary embodiment of the present application, in the above variable definitions, the distance S between the UWB vehicle-mounted sensor (mainly referring to the UWB vehicle-mounted antenna) and the UWB ground sensor 2_ID where 2_ID represents the distance between the second UWB vehicle-mounted sensor and the UWB ground sensor with the ID number. For example, S 2_128 represents the distance between the second UWB vehicle-mounted sensor and the UWB ground sensor with the ID number 182.

[0143] In an exemplary embodiment of the present application, the train estimated position calculation model can utilize the distance information from 3 UWB ground sensors to the UWB vehicle-mounted antenna, and adopt the trilateration method to calculate the spatial coordinates of the UWB vehicle-mounted antenna.

[0144] In an exemplary embodiment of the present application, before calculating the spatial coordinates of the UWB vehicle-mounted antenna using the trilateration method, UWB sensor data preprocessing can be performed first. UWB sensor data preprocessing is to screen out the information for calculating the train position in this cycle from the received UWB ground sensor information.

[0145] In an exemplary embodiment of the present application, the communication distance between the UWB vehicle-mounted sensor and the UWB ground sensor can reach up to 2000m. Therefore, according to the UWB ground sensor installation scheme, each UWB vehicle-mounted sensor can receive multiple groups of UWB ground sensor group information. To improve the calculation accuracy, the algorithm selects the UWB ground sensor group information in the same line ramp section as the UWB vehicle-mounted sensor for calculation.

[0146] In an exemplary embodiment of the present application, a UWB vehicle-mounted sensor can finally screen out the distance information sent by 4 UWB ground sensors, which are respectively denoted as S i_1 、S i_2 、S i_3 and S i_4 . Among them, i represents the vehicle-mounted sensor number, and the values are 1, 2, 3, corresponding to 3 UWB vehicle-mounted sensors.

[0147] In an exemplary embodiment of the present application, each UWB ground sensor group has 4 ground sensors, and 3 of them can determine a plane. Therefore, it is necessary to determine which 3 ground sensors are used to construct the plane, and 3 ground sensors can be selected from 4 UWB ground sensors.

[0148] In an exemplary embodiment of the present application, as Figure 6 shown, the coordinates of the 4 ground sensors are D1(x D1 , y D1 , z D1 ), D2(x D2 , y D2 , z D2 ), D3(x D3 , y D3 , z D3 ), D4(x D4 , y D4 , z D4 ) on the plane with a ramp of α, following the layout principle of the positioning reference point. The detailed selection method includes:

[0149] 1) Use D1, D2, and D3 to determine a plane and obtain the normal vector of this plane.

[0150] First, use the coordinates of D1, D2, and D3 and the cross - product method to obtain the normal vector of the plane formed by these 3 points. Where i, j, and k are the unit vectors in each dimension in three - dimensional space.

[0151] Perpendicular to the vector Then:

[0152]

[0153] According to the calculation formula (1), a, b, and c can be solved:

[0154] a=(y D2 - y D1 )·(z D3 - z D1 )-(y D3 - y D1 )·(z D2 - z D1 );

[0155] b=(z D2 - z D1 )·(x D3 - x D1 )-(z D3 - z D1 )·(x D2 - x D1 );

[0156] c=(x D2 - x D1 )·(y D3 - y D1 )-(x D3 - x D1 )·(y D2 - y D1 ).

[0157] 2) Use to determine whether D4 is on the same plane. If D4 is on the same plane as the other 3 ground sensors, then the vector D3D4(x D4 - x D3 , y D4 - y D3 , z D4 - z D3 ) should be perpendicular to the normal vector Then there is:

[0158]

[0159] If the calculation formula (2) holds, it means that the 4 ground sensors are on the same plane. When determining the train position, the plane determined by D1, D2, and D3 can be used.

[0160] If the calculation formula (2) does not hold, then calculate the inclination angle between D3D4 and the plane. When the inclination angle is less than the preset threshold limitAngle, continue to use the plane determined by D1, D2, and D3; if it exceeds the threshold limitAngle, it means that there is a large installation error in a certain ground sensor, and calculate the inclination angle β between the plane determined by every 3 ground sensors and the actual horizontal plane. i Compare it with the ramp α where the positioning base station group is located, and select the plane closest to α:

[0161] 1) The inclination angle between the plane determined by D1, D2, and D3 and the horizontal plane is β1, and the difference from α is θ1;

[0162] 2) The inclination angle between the plane determined by D1, D2, and D3 and the horizontal plane is β2, and the difference from α is θ2;

[0163] 3) The inclination angle between the plane determined by D1, D2, and D3 and the horizontal plane is β3, and the difference from α is θ3;

[0164] For example, if θ1 is the smallest, then select the plane determined by D1, D2, and D3 as the calculation basis. In the exemplary embodiment of the present application, due to the merger of the line ramp section and the installation error of the UWB ground sensor, etc., it may actually cause the UWB vehicle-mounted antenna and 3 UWB ground sensors not to be on the same plane, resulting in a trilateral positioning calculation error; therefore, before calculating the spatial coordinates of the UWB vehicle-mounted antenna, the distance information from 3 UWB ground sensors to the UWB vehicle-mounted antenna can be corrected first to ensure the accuracy of this distance information.

[0165] In the exemplary embodiment of the present application, the line ramp calculation module calculates the ramp information where the UWB vehicle-mounted sensor antenna of the current train is located, and can be used for UWB ranging correction calculation.

[0166] In the exemplary embodiment of the present application, when the wheels do not slip, the wheel acceleration is closest to the actual acceleration of the train. Therefore, based on the acceleration measured by the acceleration sensor, the line ramp acceleration can be calculated to obtain the ramp value. If the wheels slip, the wheel acceleration is no longer accurate. At this time, the line ramp value in the line database is used. The detailed solution will be introduced below.

[0167] In the exemplary embodiment of the present application, before calculating the spatial coordinates of the UWB vehicle-mounted antenna using the distance information and the coordinates of the UWB ground sensors, the method may further include:

[0168] Obtain the line ramp angle where the UWB ground sensor is located and the train ramp angle where the UWB vehicle-mounted antenna is located;

[0169] Use the line ramp angle and the train ramp angle to correct the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna.

[0170] In an exemplary embodiment of the present application, as Figure 7 shown, obtaining the line ramp angle where the UWB vehicle-mounted antenna is located may include steps S201 - S206:

[0171] S201. Obtain the original wheel speed measured by the speed sensors provided on each wheel, and filter the original wheel speed measured by the speed sensors to obtain the first wheel speed.

[0172] In an exemplary embodiment of the present application, the filtered wheel speed of the speed sensors in the previous cycle (n - 1) may be used to filter the original wheel speed V raw_i (i = 1, 2) of the speed sensors in the current cycle (n) to obtain the filtered wheel speed V wheel_i (n) of the speed sensors in the current cycle (n):

[0173]

[0174] where p = P_VWHEEL, which is the wheel speed filtering parameter; the filtered wheel speed V wheel_i (n) of the speed sensors in the current cycle (n) is the above-mentioned first wheel speed.

[0175] S202. Calculate the first wheel acceleration according to the first wheel speed.

[0176] In an exemplary embodiment of the present application, the filtered wheel speed V wheel_i (n - 1) in the previous cycle (n - 1) and the filtered wheel speed V wheel_i (n) in the current cycle (n) may be used to calculate the wheel acceleration A wheel_i (n) in the current cycle, and the calculation formula includes:

[0177]

[0178] In an exemplary embodiment of the present application, the wheel acceleration A wheel_i (n) in the current cycle is the above-mentioned first wheel acceleration.

[0179] S203. Obtain the original wheel acceleration measured by the acceleration sensors provided on each wheel, and filter the original wheel acceleration measured by the acceleration sensors to obtain the second wheel acceleration.

[0180] In an exemplary embodiment of the present application, the average value of the original acceleration measured by the acceleration sensors in this period (n) can be filtered according to the acceleration measured by the acceleration sensors in the previous period (n - 1) to obtain the acceleration A measured by the acceleration sensors in this period. meas (n):

[0181]

[0182] Wherein, p = P_AMEAS, which is the filtering parameter of the acceleration sensor, and the acceleration A measured by the acceleration sensors in this period meas (n) is the above-mentioned second wheel acceleration. In an exemplary embodiment of the present application, prior to this, the data of the speed sensors can be preprocessed by the speed sensor preprocessing sub-module in the data preprocessing module first:

[0183] 1) Judgment of the validity of the acceleration sensor data:

[0184] If the measured acceleration value of the acceleration sensor does not meet the following conditions:

[0185] SYSTEM_MINIMUM_ACCELERATION (preset system minimum acceleration) < A raw_i < SYSTEM_MAXIMUM_ACCELERATION (preset system maximum acceleration);

[0186] Then it is determined that the acceleration value measured by the acceleration sensor in this period is invalid and cannot be used for data calculation in this period.

[0187] 2) Calculate the average acceleration of the acceleration sensor:

[0188] According to the effective values of the original accelerations of the acceleration sensors collected, the average value A of the original accelerations of the acceleration sensors can be calculated raw :

[0189] ① If the original accelerations of all three acceleration sensors are valid:

[0190]

[0191] Wherein, A raw_1 、A raw_2 、A raw_3 are the original accelerations of the three acceleration sensors respectively.

[0192] ② If the raw accelerations of the two acceleration sensors are valid (assuming that the raw accelerations of acceleration sensor 1 and acceleration sensor 2 are valid):

[0193]

[0194] ③ If the raw acceleration of only one acceleration sensor is valid, the algorithm will no longer perform the average calculation of the acceleration.

[0195] S204. Calculate the line ramp acceleration corresponding to each wheel according to the difference between the first wheel acceleration and the second wheel acceleration.

[0196] In an exemplary embodiment of the present application, according to the difference between the accelerations after filtering by the acceleration sensor and the speed sensor in the previous cycle [i.e., A meas (n - 1) and A wheel_i (n)], the difference between the acceleration A meas (n) measured by the acceleration sensor in this cycle (i.e., the first wheel acceleration) and the wheel acceleration A wheel_i (n) obtained from the speed sensor in this cycle (i.e., the second wheel acceleration) is filtered to obtain the difference A dif_i after filtering by the speed sensor and the acceleration sensor in this cycle:

[0197]

[0198] where p = P_ADIF, which is the filtering parameter for the difference between the wheel acceleration and the acceleration sensor acceleration;

[0199] The line ramp acceleration A grade_i (n) corresponding to each wheel in this cycle:

[0200]

[0201] S205. Determine the final line ramp acceleration according to whether the wheel slips or idles and the line ramp acceleration corresponding to each wheel.

[0202] In an exemplary embodiment of the present application, the determining the final line ramp acceleration according to whether the wheel slips or idles and the line ramp acceleration corresponding to each wheel may include:

[0203] When neither of the two wheels slips or idles, calculate the average value of the line ramp accelerations corresponding to the two wheels as the final line ramp acceleration;

[0204] When any one of the wheels slips or idles, use the line ramp acceleration corresponding to the wheel that does not slip or idle as the final line ramp acceleration;

[0205] When both wheels spin or skid, use the data in the line database as the final line ramp acceleration.

[0206] In an exemplary embodiment of the present application, if neither wheel spins or skids, then according to the ramp acceleration A grade_i (n - 1) of the previous cycle and the acceleration A meas (n) measured by the acceleration sensor in this cycle (i.e., the first wheel acceleration) and the wheel acceleration A wheel_i (n) obtained from the speed sensor in this cycle (i.e., the second wheel acceleration), calculate the ramp acceleration A grade_i (n) of this cycle:

[0207]

[0208] Take the average value of the ramp accelerations of the two wheels in this cycle as the ramp acceleration A grade (n) of this cycle:

[0209]

[0210] If only one wheel does not spin or skid, then the ramp acceleration of this cycle can be calculated according to calculation formula (9);

[0211] If both wheels spin or skid, use the data in the line database as the ramp acceleration of this cycle. In an exemplary embodiment of the present application, the method for determining whether a wheel spins or skids may include an acceleration detection method, and this acceleration detection method may include: determining whether a wheel spins or skids according to the change magnitude of the difference between the first wheel acceleration and the second wheel acceleration from one cycle to the next cycle, and the magnitude of the absolute value of the difference between the first wheel acceleration and the second wheel acceleration. In an exemplary embodiment of the present application, the method for determining whether a wheel spins or skids may further include a speed difference detection method, and this speed difference detection method may include:

[0212] When it is not detected whether the wheel spins or skids according to the change magnitude and the absolute value magnitude of the difference between the first wheel acceleration and the second wheel acceleration, detect whether the wheel spins or skids according to preset limit conditions.

[0213] In an exemplary embodiment of the present application, the acceleration detection method and the speed difference detection method can be used to determine whether a wheel spins or skids through a wheel spin / skid judgment model:

[0214] (1) Acceleration detection method

[0215] If any of the following conditions occur for a speed sensor, set the acceleration idle or coasting detection flag corresponding to that speed sensor to true:

[0216] 1) A dif_i The change from one period to the next exceeds ASLIP_TOL (the threshold for determining idle / coasting based on the change in acceleration difference);

[0217] 2) |A dif_i | is greater than AH_LIMIT (the threshold for determining idle / coasting based on the acceleration difference);

[0218] (2) Speed difference detection method

[0219] When the speed sensor does not detect any idle / coasting, calculate the speed difference idle / coasting detection limit condition Speed_Slip_Limit_i(n), which is adjusted according to the current speed:

[0220] Speed_Slip_Limit_i(n) = max[V dif (n), Speed_Slip_Limit_Min]; (12)

[0221] Where: The calculation formula for Speed_Slip_Limit_Min is as follows

[0222] When the estimated speed V of the train calculated_i < VCALCULATED_LoW:

[0223] Speed_Slip_Limit_Min = VELOCITY_SLIP_LIMIT_MIN_LOW; (13)

[0224] When V calculated_i ≥ VCALCULATED_LOW:

[0225] Speed_Slip_Limit_Min = VELOCITY_SLIP_LIMIT_MIN_HIGH; (14)

[0226] Where:

[0227] Speed_Slip_Limit_i is the threshold for determining idle / coasting by the speed difference method in this period;

[0228] V dif is the difference between the speed transmitted in this period and the speed integrated by the accelerometer; Speed_Slip_Limit_Min is the minimum threshold for determining idle / coasting by the speed difference;

[0229] Vcalculated_i is the estimated speed for this period;

[0230] VCALCULATED_LOW is the lower threshold for speed judgment;

[0231] VCALCULATED_HIGH is the higher threshold for speed judgment;

[0232] VELOCITY_SLIP_LIMIT_MIN_LOW is the minimum value of the threshold for idling and coasting judgment;

[0233] VELOCITY_SLIP_LIMIT_MIN_LOW is the maximum value of the threshold for idling and coasting judgment.

[0234] When the acceleration idling / coasting detection flag is false, but the speed difference idling / coasting detection flag is true, since the speed difference idling / coasting detection method is a secondary idling / coasting detection means, when acceleration idling / coasting is not detected, it is necessary to increase the detection limit conditions of the speed difference idling / coasting detection method to reduce the occurrence of untrustworthy states. The calculation of the speed difference idling / coasting detection limit condition Speed_Slip_Limit can include:

[0235] Speed_Slip_Limit_i(n) = Speed_Slip_Limit_i(n - 1)+VELOCITY_SLIP_LIMIT_ADD; (15)

[0236] Temp = min[SPEED_SLIP_LIMIT_MAX, V calculated / 2],

[0237] Temp = max[Temp, Speed_Slip_Limit_Min];

[0238] When Speed_Slip_Limit_i(n)>Temp,

[0239] Speed_Slip_Limit_i(n) = Temp; (16)

[0240] Where:

[0241] Speed_Slip_Limit_i is the threshold for judging idling and coasting by the speed difference method in this period;

[0242] VELOCITY_SLIP_LIMIT_ADD is the supplementary value of the threshold for judging idling and coasting by the speed difference method;

[0243] Speed_Slip_Limit_Min is the minimum threshold value for judging idling and sliding by speed difference.

[0244] Speed_Slip_Limit_Max is the maximum threshold value for judging idling and sliding by speed difference.

[0245] V calculated is the estimated speed of this cycle.

[0246] When the acceleration idling / sliding detection flag is true, since the acceleration idling / sliding detection method is the first detection method, when the acceleration idling / sliding detection method detects idling / sliding, the speed difference idling / sliding detection method should reduce the detection conditions to improve the sensitivity of the speed difference idling / sliding detection method. Calculating the speed difference idling / sliding detection limit condition Speed_Slip_Limit can include:

[0247]

[0248] Among them:

[0249] Speed_Slip_Limit_i is the threshold value for judging idling and sliding by the speed difference method in this cycle.

[0250] VELOCITY_SLIP_LIMIT_SUB: is the reference value for the threshold of judging idling and sliding by the speed difference method.

[0251] Since the speed of the previous cycle is used when calculating the threshold of idling / sliding and the running speed of the train, the basis for judging idling / sliding in this cycle is: if |V dif_i (n)| > Speed_Slip_Limit_i(n - 1), then the flag of the speed difference idling / sliding detection method of this speed sensor is marked as true, indicating that idling / sliding is detected.

[0252] The state of idling and sliding needs to be combined with the type of axle.

[0253] (1) If the axle where the speed sensor is located is a driving axle, the possible states of the wheel are no idling / sliding state, idling / sliding state, idling state, sliding state, and untrustworthy state;

[0254] (2) If the axle where the speed sensor is located is a braking axle, the possible states of the wheel are no idling / sliding state, idling / sliding state, sliding state, and untrustworthy state; if the idling state is judged, it is classified as the untrustworthy state;

[0255] (3) If the axis where the speed sensor is located is the rolling axis, the possible states of the wheel are no idling / sliding state and untrustworthy state; if the idling state, sliding state, and idling / sliding state are judged, they are classified as untrustworthy states.

[0256] Based on the idling and sliding state of the train judged according to whether there is a speed difference and an acceleration difference, and the type of axle where the speed sensor is located, the idling and sliding are further subdivided, and finally it is judged that the wheel is in:

[0257] 1) Normal state, no idling or sliding;

[0258] 2) Idling and sliding judgment state, it is necessary to continue to observe to identify whether it is idling, sliding, or untrustworthy;

[0259] 3) Idling state: The wheel speed is higher than the train speed;

[0260] 4) Sliding state: The wheel speed is lower than the train speed;

[0261] 5) Untrustworthy state: Contrary to the physical phenomenon (for example, the speed sensor on the braking axle judges an idling state), it may be that the sensor fails and the error is large.

[0262] S206. Calculate the line ramp angle according to the final line ramp acceleration.

[0263] In the exemplary embodiment of the present application, the line ramp angle of this period, that is, ramp γ(n), can be calculated according to the ramp acceleration value and the following calculation formula:

[0264]

[0265] In the exemplary embodiment of the present application, the correction of the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna by using the line ramp angle and the train ramp angle may include:

[0266] Calculate the included angle between the UWB ground sensor and the UWB vehicle-mounted antenna according to the line ramp angle and the train ramp angle;

[0267] Calculate the corrected distance information between the UWB ground sensor and the UWB vehicle-mounted antenna according to the included angle between the UWB ground sensor and the UWB vehicle-mounted antenna and the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna.

[0268] In an exemplary embodiment of the present application, there are merges in the line ramp section, installation errors of UWB ground sensors, etc. Therefore, in fact, it will cause the UWB vehicle-mounted antenna and the three UWB ground sensors not to be in the same plane, resulting in trilateration calculation errors. Therefore, the line ramp angle and the train ramp angle can be used to correct the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna, as Figure 8 shown, is a schematic diagram of ramp correction.

[0269] In an exemplary embodiment of the present application, let the ramp angle where the UWB vehicle-mounted antenna is located be γ, the ramp angle where the UWB ground sensor is located be β, and the distances between the UWB vehicle-mounted antenna and the three UWB ground sensors be d1, d2, and d3 respectively; then the angle θ between the UWB vehicle-mounted antenna and the first UWB ground sensor is:

[0270] θ = β - γ; (19)

[0271] Therefore, the actual distance d′1 between the UWB vehicle-mounted antenna and the UWB ground sensor can be calculated as:

[0272] d′1 = d1·cosθ; (20)

[0273] In an exemplary embodiment of the present application, similarly, the actual distance d′2 between the UWB vehicle-mounted antenna and the second UWB ground sensor and the actual distance d′3 between the UWB vehicle-mounted antenna and the third UWB ground sensor can be calculated.

[0274] In an exemplary embodiment of the present application, the calculation of the spatial coordinates of the UWB vehicle-mounted antenna using the distance information and the coordinates of the UWB ground sensor may include:

[0275] Taking the spatial coordinates of the UWB vehicle-mounted antenna as unknowns, and listing a system of equations about the unknowns according to the coordinates of the UWB ground sensor, the spatial coordinates of the UWB vehicle-mounted antenna, the distance information, and the distance formula between two points;

[0276] Solving the system of equations to obtain the spatial coordinates of the UWB vehicle-mounted antenna.

[0277] In an exemplary embodiment of the present application, as Figure 9 shown, there are three UWB ground sensors D1(x D1 , y D1 , z D1 ), D2(x D2 , y D2 , z D2 ), D3(x D3 , y D3 , z D3 ).

[0278] In an exemplary embodiment of the present application, a plane can be obtained based on the coordinates of three UWB ground sensors, and the solution of the plane equation is as follows:

[0279] Find the normal vector of the plane The solution of the normal vector is as shown in the calculation formula (1), and then the plane calculation formula is obtained according to the normal vector:

[0280] ax + by + cz + d = 0 (21)

[0281] where d = -ax D1 -by D1 -cz D1 .

[0282] In an exemplary embodiment of the present application, assuming that the UWB vehicle-mounted antenna and the UWB ground sensor are on the same plane, a distance equation set about the spatial coordinates P(x, y, z) of the UWB vehicle-mounted antenna on the plane is obtained by using the distances from the UWB vehicle-mounted antenna to the three UWB ground sensors, the spatial coordinates of the UWB ground sensors, and the distance formula. Squaring both sides of the distance equation set, the following equation is obtained:

[0283] d′1 2 =(x D1 -x) 2 +(y D1 -y) 2 +(z D1 -z) 2 ; (22)

[0284]

[0285]

[0286] According to the calculation formulas (22), (23), and (24), the spatial coordinates of the UWB vehicle-mounted antenna can be solved.

[0287] In an exemplary embodiment of the present application, according to the above calculation scheme, the spaces of the three UWB vehicle-mounted antennas can be calculated as P1(x1, y1, z1), P2(x2, y2, z2), and P3(x3, y3, z3) respectively.

[0288] In an exemplary embodiment of the present application, the method may further include:

[0289] Calculating a first distance between the UWB vehicle-mounted antenna and a preset positioning reference point on the line according to the spatial coordinates of the UWB vehicle-mounted antenna;

[0290] Calculate a third distance between the front of the vehicle and the positioning reference point according to the first distance and a second distance from the UWB vehicle-mounted antenna to the front of the vehicle;

[0291] Calculate a distance from the front of the vehicle to a starting point of a track section according to the third distance and a distance between the positioning reference point and the starting point of the track section;

[0292] Use the distance from the front of the vehicle to the starting point of the track section as the positioning information of the train.

[0293] In an exemplary embodiment of the present application, after obtaining the spatial coordinates of the UWB vehicle-mounted antenna, the distances between the three UWB vehicle-mounted antennas and the positioning reference point can be calculated according to the spatial coordinates of the three UWB vehicle-mounted antennas and the spatial coordinates of the positioning reference point, and then the distance from the front of the train to the positioning reference point can be calculated according to the distances from the three UWB vehicle-mounted antennas to the front of the vehicle. Finally, according to the distance from the front of the train to the positioning reference point in the current period and the position of the track section where the positioning reference point is located, the position of the track section where the train is located in the current period is calculated.

[0294] In an exemplary embodiment of the present application, after the line is built, the three-dimensional map information of the line can be collected to make an electronic map. Given the spatial coordinates of the three antennas and the spatial coordinates of the positioning reference point, combined with the electronic map, the position of the train in the electronic map can be identified, and the relative distance from the vehicle-mounted antenna to the positioning reference point can be calculated.

[0295] In an exemplary embodiment of the present application, when calculating the distance of the train position relative to the positioning reference point, the shape of the track needs to be considered. If the track is a straight track with a constant slope, the spatial coordinates of the positioning reference point and the vehicle-mounted antenna can be directly used for calculation. If the track section is a curved track, it is necessary to calculate in combination with the radius of curvature of the curve in the electronic map and the starting and ending points of the curve. The following details are given for the two cases respectively.

[0296] Case 1: The track section is a straight track on the same slope

[0297] In an exemplary embodiment of the present application, the following gives an example of calculating the distance between the UWB vehicle-mounted antenna and the positioning reference point:

[0298] In an exemplary embodiment of the present application, it can be assumed that the spatial coordinates of the i-th (i is a positive integer) positioning reference point are G(x G_i , y G_i , z G_i ), then the distances between the UWB vehicle-mounted antennas 31, 32, and 33 and the positioning reference point can be calculated as S1, S2, and S3 respectively according to the spatial distance formula;

[0299] S1 = (x1 - x G_i ) 2+(y1 - y G_i ) 2 +(z1 - z G_i ) 2 ; (25)

[0300] S2 = (x2 - x G_i ) 2 +(y2 - y G_i ) 2 +(z2 - z G_i ) 2 ; (26)

[0301] S3 = (x3 - x G_i ) 2 +(y3 - y G_i ) 2 +(z3 - z G_i ) 2 。 (27)

[0302] Case 2: The track section contains a curve (horizontal or vertical)

[0303] In the exemplary embodiment of the present application, the schematic diagram of curve positioning can be as shown in Figure 10 . Map the spatial coordinates of the vehicle-mounted antenna and the spatial coordinates of the positioning reference point to the electronic map, and then consult the electronic map to obtain the distance between the two points.

[0304] In the exemplary embodiment of the present application, given the position of the positioning reference point 4 and the position of the vehicle-mounted antenna, according to the track information in the electronic map (including information such as the starting point, ending point, length, slope change, curvature change, etc.), the distance S x is obtained, where x represents the number of the vehicle-mounted antenna.

[0305] In the exemplary embodiment of the present application, the detailed solution method can be determined according to the encapsulated information in the electronic map. An existing data method can be adopted. The following is only an example of one case:

[0306] As shown in Figure 11 , assuming that the track slope between the balises 4 and 5 is the same and the radius of curvature R remains unchanged: Then, based on the distance from the vehicle-mounted antenna to the balise 4, the sine value of the corresponding angle can be solved, and then the angle can be obtained by looking up the table, and multiplied by the circumference to obtain the curve distance; L 4-c is the straight-line distance from the balise 4 to the vehicle-mounted antenna C, S 4-c is the straight-line distance from the balise 4 to the vehicle-mounted antenna C; sinδ = (R × L 4-c ) / 2;

[0307] In the exemplary embodiments of the present application, it should be noted that: there is a significant deviation in the spatial coordinates of the vehicle-mounted antenna from the ground track. When setting the coordinates of the ground positioning reference point, this deviation needs to be converted to be as close as possible to the same horizontal plane as the vehicle-mounted antenna (relative to the track plane):

[0308] 1) The positioning reference point is on the ground, in the middle of the track: When setting the spatial coordinates, the height of the train perpendicular to the track needs to be added.

[0309] 2) The positioning reference point is not on the ground: Then, the vertical and horizontal offsets of the positioning reference point relative to the track need to be considered.

[0310] In the exemplary embodiments of the present application, the following gives a calculation example of the distance between the train head and the positioning reference point:

[0311] Assume that the distances of the UWB vehicle-mounted antennas 31, 32, and 33 from the train head are L1, L2, and L3 respectively. Then the distances S G_1 , S G_2 and S G_3 between the train head and the positioning reference point can be calculated as follows:

[0312] S G_1 = S1 + L1; (28)

[0313] S G_2 = S2 + L2; (29)

[0314] S G_3 = S3 + L3. (30)

[0315] In the exemplary embodiments of the present application, the calculated distance between the train head and the positioning reference point can be judged for validity.

[0316] In the exemplary embodiments of the present application, the validity judgment method may include, but is not limited to: the pairwise comparison method of vehicle-mounted antennas, and the comparison method of the distance calculated by UWB and the distance calculated by non-UWB.

[0317] In the exemplary embodiments of the present application, the pairwise comparison method of vehicle-mounted antennas:

[0318] For the three distances S G_1 , S G_2 and S G_3 between the train head and the positioning reference point, the validity judgment is carried out, including: pairwise comparing the distances S G_1 , S G_2 and S G_3 between the train head and the positioning reference point. If the difference in the comparison results is not within the preset distance comparison threshold range (TOL_DISTANCE_COMPARE), then the distance is considered invalid: If SG_1 and S G_2 The comparison with S is out of range, and S G_1 and S G_3 If the comparison with S is out of range, then set S G_1 to be abnormal; otherwise, set S G_1 to be normal.

[0319] In an exemplary embodiment of the present application, therefore, if S G_1 , S G_2 and S G_3 are all normal, then the distance S of the train head from the positioning reference point is G as follows:

[0320]

[0321] If S G_1 is abnormal, S G_2 and S G_3 are all normal, then the distance S of the train head from the positioning reference point is G as follows:

[0322]

[0323] In an exemplary embodiment of the present application, that is, the method may further include: G The distance S of the on-vehicle antenna relative to the positioning reference point obtained by using UWB positioning, and the distance obtained by using non-UWB positioning is S estimate_offset . If the error between the two exceeds TOL_DISTANCE_DIFF_COMPARE, then give a warning to indicate that the positioning result is abnormal.

[0324] In an exemplary embodiment of the present application, that is, the method may further include:

[0325] Calculate the ranging error according to the ranging information of the axle speed sensor and the acceleration sensor, and the ranging information of the UWB ground sensor and the UWB on-vehicle sensor, and verify the positioning information of the train according to the magnitude of the ranging error.

[0326] In an exemplary embodiment of the present application, the calculating the ranging error according to the ranging information of the axle speed sensor and the acceleration sensor, and the ranging information of the UWB ground sensor and the UWB on-vehicle sensor, and verifying the positioning information of the train according to the magnitude of the ranging error may include:

[0327] Estimate the wheel speed according to the acquisition data of the axle speed sensor and the acceleration sensor, and calculate the traveling distance of the train by using the estimated vehicle speed;

[0328] Calculate the displacement of the train relative to the positioning reference point according to the walking distance and the preset positioning reference point;

[0329] Calculate the distance between the train and the positioning reference point according to the positioning information of the train obtained by the UWB ground sensor and the UWB vehicle-mounted sensor;

[0330] Compare the calculated displacement with the distance to calculate the ranging error;

[0331] When the ranging error is greater than the preset difference threshold, confirm that the positioning information of the train is abnormal; when the ranging error is less than or equal to the preset difference threshold, confirm that the positioning information of the train is normal.

[0332] In the exemplary embodiment of the present application, the estimated wheel speed can be implemented by a train estimated speed calculation model.

[0333] In the exemplary embodiment of the present application, the wheel speed per cycle can be calculated by a train estimated speed calculation model:

[0334] (1) Acceleration integral speed calculation

[0335] It is known that the estimated speed of the train in the previous cycle is v pre_estimate , the acceleration of the train measured by the acceleration sensor in this cycle is A raw , the sampling period is T cycle , then the acceleration integral speed V acc in this cycle is:

[0336] V acc = v pre_estimate + A raw * T cycle (33)

[0337] (2) Axle speed sensor speed calculation

[0338] The train speed V wheel obtained from the wheels, due to reasons such as the accuracy and installation error of the axle speed sensor, it is filtered before use.

[0339] Let the wheel speed in the previous cycle be V pre_wheel , that is, the aforementioned V w h eel_i (n - 1), the original speeds collected by the axle speed sensors of two wheels (such as wheel 1 and wheel 2) in this cycle are V raw_1 and V raw_2 , the filtering parameter is p wheel , the sampling period is T cycle , then the wheel speeds of the two wheels after filtering in this cycle are respectively:

[0340]

[0341]

[0342] In an exemplary embodiment of the present application, based on the judging result of wheel idling and coasting, the data of wheel 1 and wheel 2 can be corrected, which may include:

[0343] If both wheels 1 and 2 are normal, then v cal_wheel1 and v cal_wheel2 are the calculation results of formula (34) and formula (35).

[0344] If only wheel 1 idles and coasts and wheel 2 is normal, then the filtering result of wheel 2 is given to wheel 1:

[0345] v cal_wheel1 = v cal_wheel2 (36)

[0346] If only wheel 2 idles and coasts and wheel 1 is normal, then the filtering result of wheel 1 is given to wheel 2:

[0347] v cal_wheel2 = v cal_wheel1 ; (37)

[0348] If both wheels 1 and 2 idle and coast, use the acceleration value to calculate:

[0349]

[0350]

[0351] Finally, calculate the wheel speed V wheel (i.e., the aforementioned speed V wheel_i (n)):

[0352]

[0353] In an exemplary embodiment of the present application, the UWB speed can also be calculated, and the final wheel speed can be estimated based on the UWB speed. At this time, the wheel speed can be represented by v estimate .

[0354] In an exemplary embodiment of the present application, calculating the UWB speed may include: calculating the time difference T uwb_diff and the displacement difference S uwb_diff between two UWB localizations according to the distance and timestamp calculated by UWB. The UWB speed in this cycle is V uwb :

[0355]

[0356] In an exemplary embodiment of the present application, estimating the final wheel speed may include: performing data fusion on the axle speed sensor and the acceleration sensor after preprocessing.

[0357]

[0358] Wherein:

[0359] 1 = p1 + p2 + p3 (43)

[0360] Wherein, there are 3 sets of values for p1, p2, and p3, and different values are set in 3 scenarios respectively:

[0361] 1) In a conventional track section, no wheel spin or skid occurs, or wheel spin or skid occurs on a single wheel: p1 and p2 are relatively large;

[0362] 2) In a rack track section, no wheel spin or skid occurs, or wheel spin or skid occurs on a single wheel: p1 and p3 are relatively large;

[0363] 3) Double-wheel spin or skid: The proportion of p2 continues to decrease.

[0364] In an exemplary embodiment of the present application, the distance information of the positioning reference point can be calibrated according to the distance determined by the speed sensor and the acceleration sensor. The estimated speed v of the train has been obtained estimate , and by integrating the speed over time, the displacement S of the train is obtained estimate .

[0365] S estimate = ∑(v estimate * T cycle ) (44)

[0366] When passing through the positioning reference point, S estimate is calibrated to obtain the distance S estimate_offset relative to the positioning reference point.

[0367] There are many calibration methods, which are relatively mature. The equal-ratio method is taken as an example for illustration below.

[0368] After receiving the information of the positioning reference point, record the timestamp T stamp , and then search for the two sets of speed information and their corresponding timestamps before and after: v estimate_1 , S estimate_1 , t estimate_1 , v estimate_2 , S estimate_2 , t estimate_2 .

[0369] According to the splitting ratio of T stamp between t estimate_1 and t estimate_2 , obtain T stampv at a moment estimate_stamp and S estimate_stamp 。

[0370]

[0371] Then:

[0372]

[0373] S estimate_offset = S estimate - S estimate_stamp 。 (47)

[0374] In an exemplary embodiment of the present application, the distance S of the vehicle-mounted antenna obtained by UWB positioning relative to the positioning reference point G , the distance obtained by non-UWB positioning is S estimate_offset , if the error between the two exceeds TOL_DISTANCE_DIFF_COMPARE, a warning is given to indicate that the positioning result is abnormal.

[0375] In an exemplary embodiment of the present application, a valid vehicle-mounted antenna is used. According to the spatial coordinates of the vehicle-mounted antennas 31, 32, 33 and L1, L2, L3, and according to the aforementioned UWB sensor data preprocessing scheme and the spatial coordinate calculation method of the UWB vehicle-mounted sensor antenna, the spatial coordinates G(x, y, z) of the train head can be obtained. In an exemplary embodiment of the present application, the distance of the train head from the starting point of the track section can be calculated as the positioning data of the current train. Let the distance of the positioning reference point from the starting point of the track section be S0, then the distance S of the train head from the starting point of the track section offset is:

[0376] S offset = S G + S0. (48)

[0377] In an exemplary embodiment of the present application, based on the axle speed sensor and the acceleration sensor, a UWB ranging system is added, so that on the basis of taking into account the existing speed measurement scheme, active positioning of the train is realized in mountain rail transit where it is difficult to install transponders.

[0378] The embodiment of the present application also provides a rail transit train positioning system A, as Figure 12As shown, it may include: UWB ground sensor A1, UWB vehicle-mounted antenna A2, UWB vehicle-mounted host A3, speed sensor A4, acceleration sensor A5, positioning reference point A6, vehicle-mounted controller A7, and computer-readable storage medium A8. The UWB vehicle-mounted sensor includes a UWB vehicle-mounted host A3 and a UWB vehicle-mounted antenna AA2 connected to each other; instructions are stored in the computer-readable storage medium A8, and when the instructions are executed by the vehicle-mounted controller A7, the described rail transit train positioning method is implemented.

[0379] In an exemplary embodiment of the present application, the UWB vehicle-mounted antenna is directly installed on the UWB vehicle-mounted host or connected to the UWB vehicle-mounted host through wiring; the UWB vehicle-mounted antenna is vertically arranged and installed at the front end of the top of the vehicle head along the forward direction of the train;

[0380] The UWB vehicle-mounted antenna is installed at the center line position of the roof;

[0381] The installation interval between multiple UWB vehicle-mounted antennas is greater than or equal to a preset interval threshold;

[0382] At least one set of UWB ground sensors is arranged on each ramp, and each set of UWB ground sensors is distributed on both sides of the track;

[0383] The vertical height difference between the UWB ground sensor and the UWB vehicle-mounted antenna is less than or equal to a preset height threshold;

[0384] The distance between multiple positioning reference points meets the requirements of a preset distance threshold.

[0385] In an exemplary embodiment of the present application, any of the foregoing embodiments of the rail transit train positioning method is applicable to this system embodiment, and will not be elaborated here one by one.

[0386] Those of ordinary skill in the art will understand that all or some of the steps in the methods disclosed above, and the functional modules / units in systems and devices, can be implemented as software, firmware, hardware, and appropriate combinations thereof. In the hardware implementation, the division of functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be executed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is well known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassettes, tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and may include any information delivery medium.

Claims

1. A positioning method for rail transit trains, characterized in that, Ultra-wideband (UWB) ground sensors are provided on the track line, and UWB vehicle-mounted sensors are provided at the set positions of the train. The UWB vehicle-mounted sensors include a UWB vehicle-mounted host and a UWB vehicle-mounted antenna connected to each other; The method includes: Collect the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna; Obtain the line ramp angle where the UWB ground sensor is located and the train ramp angle where the UWB vehicle-mounted antenna is located; Correct the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna by using the line ramp angle and the train ramp angle, including: Calculate the included angle between the UWB ground sensor and the UWB vehicle-mounted antenna according to the line ramp angle and the train ramp angle; Calculate the corrected distance information between the UWB ground sensor and the UWB vehicle-mounted antenna according to the included angle between the UWB ground sensor and the UWB vehicle-mounted antenna and the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna; Calculate the spatial coordinates of the UWB vehicle-mounted antenna by using the corrected distance information between the UWB ground sensor and the UWB vehicle-mounted antenna and the coordinates of the UWB ground sensor; Determine the positioning information of the train according to the spatial coordinates of the UWB vehicle-mounted antenna; Among them, the calculating the corrected distance information between the UWB ground sensor and the UWB vehicle-mounted antenna according to the included angle between the UWB ground sensor and the UWB vehicle-mounted antenna and the distance information between the UWB ground sensor and the UWB vehicle-mounted antenna includes: Determine the first plane according to 3 of the UWB ground sensors; According to the included angle between the UWB ground sensor and the UWB vehicle-mounted antenna, calculate the projected distances of the distances from the UWB vehicle-mounted antenna to the 3 UWB ground sensors on the first plane respectively, so as to obtain the corrected distance information between the UWB ground sensor and the UWB vehicle-mounted antenna.

2. The rail transit train positioning method according to claim 1, characterized in that, The determining the positioning information of the train according to the spatial coordinates of the UWB vehicle-mounted antenna includes: Taking the spatial coordinates of the UWB vehicle-mounted antenna as the positioning information of the train; or, Calculate the first distance between the UWB vehicle-mounted antenna and a preset positioning reference point on the track line according to the spatial coordinates of the UWB vehicle-mounted antenna; Calculate the third distance between the head of the train and the positioning reference point according to the first distance and the second distance from the UWB vehicle-mounted antenna to the head of the train; Calculate the distance from the head of the train to the starting point of the track section according to the third distance and the distance between the positioning reference point and the starting point of the track section; Take the distance from the head of the train to the starting point of the track section as the positioning information of the train.

3. The rail transit train positioning method according to claim 1, wherein The obtaining the line ramp angle where the UWB vehicle-mounted antenna is located includes: Obtain the original wheel speeds measured by the speed sensors provided on each wheel, and filter the original wheel speeds measured by the speed sensors to obtain the first wheel speed; Calculate the first wheel acceleration according to the first wheel speed; Obtain the original wheel acceleration measured by the acceleration sensors provided on each wheel, and filter the original wheel acceleration measured by the acceleration sensors to obtain the second wheel acceleration; Calculate the line ramp acceleration corresponding to each wheel according to the difference between the first wheel acceleration and the second wheel acceleration; Determine the final line ramp acceleration according to whether the wheels are spinning or skidding, and the line ramp acceleration corresponding to each wheel; Calculate the line ramp angle according to the final line ramp acceleration; 4. The rail transit train positioning method according to claim 3, characterized in that, The determining the final line ramp acceleration according to whether the wheels are spinning or skidding, and the line ramp acceleration corresponding to each wheel includes: When neither of the two wheels is spinning or skidding, calculate the average value of the line ramp accelerations corresponding to the two wheels as the final line ramp acceleration; When any one of the wheels is spinning or skidding, use the line ramp acceleration corresponding to the wheel that is not spinning or skidding as the final line ramp acceleration; When both wheels are spinning or skidding, use the data in the line database as the final line ramp acceleration; 5. The rail transit train positioning method according to claim 1, characterized in that The method further includes: Calculate the ranging error according to the ranging information of the axle speed sensor and the acceleration sensor, and the ranging information of the UWB ground sensor and the UWB vehicle-mounted sensor, and calibrate the positioning information of the train according to the magnitude of the ranging error; 6. The rail transit train positioning method according to claim 5, characterized in that The calculating the ranging error according to the first ranging information of the axle speed sensor and the acceleration sensor, and the second ranging information of the UWB ground sensor and the UWB vehicle-mounted sensor, and calibrating the positioning information of the train according to the magnitude of the ranging error includes: Estimate the wheel speed according to the acquisition data of the axle speed sensor and the acceleration sensor, and calculate the traveling distance of the train using the estimated vehicle speed; Calculate the displacement of the train relative to the positioning reference point according to the traveling distance and the preset positioning reference point; Calculate the distance between the train and the positioning reference point according to the positioning information of the train obtained by the UWB ground sensor and the UWB vehicle-mounted sensor; Compare the calculated displacement with the distance to calculate the ranging error; When the ranging error is greater than the preset difference threshold, confirm that the positioning information of the train is abnormal; when the ranging error is less than or equal to the preset difference threshold, confirm that the positioning information of the train is normal; 7. A rail transit train positioning system, characterized in that, Includes: Ultra-wideband UWB ground sensor, UWB vehicle-mounted sensor, speed sensor, acceleration sensor, positioning reference point, vehicle-mounted controller and computer-readable storage medium, the UWB vehicle-mounted sensor includes a UWB vehicle-mounted host and a UWB vehicle-mounted antenna connected to each other; instructions are stored in the computer-readable storage medium, and when the instructions are executed by the vehicle-mounted controller, the rail transit train positioning method according to any one of claims 1-6 is implemented; 8. The rail transit train positioning system according to claim 7, characterized in that The UWB vehicle-mounted antenna is directly installed on the UWB vehicle-mounted host or connected to the UWB vehicle-mounted host through wiring; the UWB vehicle-mounted antenna is vertically arranged and installed at the front end of the top of the vehicle head along the advancing direction of the train; The UWB vehicle-mounted antenna is installed at the center line position of the roof; The installation interval between multiple UWB vehicle-mounted antennas is greater than or equal to a preset interval threshold; At least one set of UWB ground sensors is arranged on each ramp, and each set of UWB ground sensors is distributed on both sides of the track; The vertical height difference between the UWB ground sensor and the UWB vehicle-mounted antenna is less than or equal to a preset height threshold.

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