Time synchronization method and system for multiple sensors in novel train positioning system

Abstract

The invention discloses a novel time synchronization method and system for multiple sensors in a train positioning system. The method comprises the following steps: triggering distribution of timestamps of an ultra-wideband module, a laser radar, an inertial measurement unit and a millimeter-wave radar according to a main clock; distance measurement time delay is obtained through distance measurement of the ultra-wideband module; and acquiring delay time between the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar and the central processing unit. Further, estimating clock drift rates of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar based on the delay time, and dynamically supplementing the clock drift rates; when the environment changes or the system parameters change, the time synchronization state of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter wave radar is dynamically maintained, the subsequent control of the clock drift rate is compatible, and the overall compatibility of the environment change or the system parameter change is realized. And the accuracy of time synchronization of the plurality of sensors in the novel train positioning system is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of urban rail transit, and in particular to a time synchronization method and system for multiple sensors in a novel train positioning system. Background Art

[0002] In the field of urban rail transit, the existing train autonomous speed measurement and positioning systems have gradually exposed some difficult-to-solve technical problems in the long-term actual engineering application process, such as being affected by the wheel-rail relationship, slow positioning completion / recovery, and limited equipment modification and installation. In order to solve these technical problems, the field of urban rail transit signal systems has begun to study the next generation of train speed measurement and positioning technology. At present, the mainstream of new vehicle-mounted autonomous technology is based on the multi-sensor fusion technology route.

[0003] The multiple on-board sensors include ultra-wideband modules, lidar, inertial measurement units and millimeter-wave radars. The ultra-wideband modules, lidar, inertial measurement units and millimeter-wave radars all work as the train moves. However, the accuracy of the existing time synchronization methods of urban rail transit signal systems is low. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art. The present invention provides a time synchronization method and system for multiple sensors in a novel train positioning system, which collects a master clock and initializes and configures an ultra-wideband module, a laser radar, an inertial measurement unit and a millimeter-wave radar; collects corresponding delay information based on the ranging of the ultra-wideband module; triggers the allocation of timestamps of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar according to the master clock; collects the delay time between the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar and a central processing unit, introduces the delay time, and further controls the delay time. At the same time, the allocation of timestamps of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar is realized.

[0005] Furthermore, the clock drift rates of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are estimated based on the delay time, and the clock drift rates are dynamically supplemented. During the operation of the train, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is collected. When the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained, thereby ensuring the dynamic control of the time synchronization status and being compatible with the subsequent control of the clock drift rate, achieving overall compatibility with environmental changes or system parameter changes, and ensuring the accuracy of time synchronization of multiple sensors in the new train positioning system.

[0006] An embodiment of the present invention provides a time synchronization method for multiple sensors in a novel train positioning system, which is applied to a time synchronization scenario for multiple sensors in a novel train positioning system;

[0007] The time synchronization method of multiple sensors in the novel train positioning system comprises:

[0008] Collect the master clock and initialize the configuration of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar;

[0009] Collecting corresponding delay information based on ranging of the ultra-wideband module;

[0010] Trigger the distribution of timestamps for the UWB module, LiDAR, IMU, and MMW radar based on the master clock;

[0011] Collect the delay time between the UWB module, LiDAR, IMU, and mmWave radar and the central processor;

[0012] Based on the delay time, the clock drift rates of the ultra-wideband module, the lidar, the inertial measurement unit and the millimeter-wave radar are estimated, and the clock drift rates are dynamically supplemented;

[0013] During the operation of the train, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is collected; when the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained.

[0014] Optionally, the acquisition of the master clock and initialization configuration of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter wave radar include:

[0015] Acquisition satellite timing system;

[0016] The clock corresponding to the satellite timing system is used as the master clock to collect the master clock;

[0017] Correlate the master clock, UWB module, LiDAR, IMU and mmWave radar;

[0018] Based on the master clock, ultra-wideband module, lidar, inertial measurement unit and millimeter wave radar trigger corresponding configuration;

[0019] Initialize the configuration of the ultra-wideband module, lidar, inertial measurement unit, and millimeter-wave radar;

[0020] The corresponding working parameters are matched according to the initialization configuration of the ultra-wideband module, laser radar, inertial measurement unit and millimeter wave radar.

[0021] Optionally, the collecting corresponding delay information based on ranging of the ultra-wideband module includes:

[0022] Collect data from the UWB module on the train and multiple UWB modules on the trackside;

[0023] Communicate with the UWB module on the train and multiple UWB modules on the trackside, and record corresponding communication signals;

[0024] Defining the corresponding propagation time according to the analysis of the communication signal;

[0025] Defining corresponding delay information according to the propagation time and the ranging of the ultra-wideband module;

[0026] The corresponding delay information is collected, and at this time, corresponding information processing is triggered according to the delay information.

[0027] Optionally, the triggering of the allocation of timestamps of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter wave radar according to the master clock includes:

[0028] Freeze the master clock;

[0029] Correlate the master clock with ultra-wideband modules, lidar, inertial measurement units and millimeter wave radars;

[0030] Trigger the allocation of corresponding timestamps based on the master clock and the UWB module, LiDAR, IMU, and MMW radar;

[0031] The corresponding timestamp of the ultra-wideband module, the timestamp of the laser radar, the timestamp of the inertial measurement unit and the timestamp of the millimeter-wave radar are defined according to the allocation of the timestamp.

[0032] Optionally, the delay time between the ultra-wideband module, the laser radar, the inertial measurement unit, the millimeter-wave radar and the central processor is collected, including:

[0033] Fixed frame ultra-wideband modules, lidar, inertial measurement units and millimeter wave radar;

[0034] The UWB module, LiDAR, IMU, and mmWave radar interact with the CPU separately;

[0035] The UWB module, LiDAR, IMU, and MMW radar transmit the time-stamped data to the central processing unit via a high-speed communication link, and the central processing unit caches the received data.

[0036] Based on the timestamp of the ultra-wideband module, the time difference between the laser radar, the inertial measurement unit and the millimeter-wave radar is calculated, and the corresponding timestamps are adjusted according to the time difference between the laser radar, the inertial measurement unit and the millimeter-wave radar;

[0037] The UWB module, LiDAR, IMU and MMW radar interact with the central processor, and measure the delay time of the communication link between the UWB module, LiDAR, IMU and MMW radar and the central processor.

[0038] Optionally, estimating the clock drift rates of the ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar based on the delay time, and dynamically supplementing the clock drift rates, includes:

[0039] Freeze the delay time;

[0040] estimating clock drift rates of the ultra-wideband module, the lidar, the inertial measurement unit, and the millimeter-wave radar based on the delay time;

[0041] The corresponding drift amount is matched according to the clock drift rate.

[0042] Optionally, the estimating the clock drift rates of the ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar based on the delay time, and dynamically supplementing the clock drift rates, further includes:

[0043] Dynamic compensation is performed based on the drift amount, the timestamp of the ultra-wideband module, the timestamp of the lidar, the timestamp of the inertial measurement unit, and the timestamp of the millimeter-wave radar to dynamically supplement the clock drift rate.

[0044] Optionally, during the operation of the train, the time synchronization state of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar is collected; when the environment changes or the system parameters change, the time synchronization state of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar is dynamically maintained, including:

[0045] Real-time monitoring of the dynamic operation of trains;

[0046] During the operation of the train, the compensation values ​​of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are collected;

[0047] Corresponding dynamic adjustments are made based on the compensation amounts of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar.

[0048] Optionally, during the operation of the train, the time synchronization state of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar is collected; when the environment changes or the system parameters change, the time synchronization state of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar is dynamically maintained, and further includes:

[0049] Real-time monitoring of environmental changes or system parameters;

[0050] Dynamically maintain the time synchronization state of the UWB module, LiDAR, IMU, and mmWave radar when the environment changes or system parameters change.

[0051] In addition, an embodiment of the present invention further provides a time synchronization system for multiple sensors in a novel train positioning system, wherein the time synchronization system for multiple sensors in the novel train positioning system comprises:

[0052] The acquisition module is used to acquire the main clock and initialize the configuration of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar;

[0053] The delay module is used to collect the corresponding delay information based on the ranging of the ultra-wideband module;

[0054] A timestamp module is used to trigger the allocation of timestamps for the ultra-wideband module, lidar, inertial measurement unit, and millimeter-wave radar based on the master clock;

[0055] Delay time module, used to collect the delay time between the ultra-wideband module, lidar, inertial measurement unit, millimeter-wave radar and the central processor;

[0056] A clock drift rate module is used to estimate the clock drift rates of the ultra-wideband module, the lidar, the inertial measurement unit and the millimeter-wave radar based on the delay time, and to dynamically supplement the clock drift rates;

[0057] The time synchronization module is used to collect the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar during the operation of the train; when the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained.

[0058] In an embodiment of the present invention, through the method in the embodiment of the present invention, the master clock is collected, and the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are initialized and configured; the corresponding delay information is collected based on the ranging of the ultra-wideband module; the allocation of timestamps of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is triggered according to the master clock; the delay time between the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar and the central processor is collected, the delay time is introduced, and the delay time is further controlled, and at the same time, the allocation of timestamps of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is realized.

[0059] Furthermore, the clock drift rates of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are estimated based on the delay time, and the clock drift rates are dynamically supplemented. During the operation of the train, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is collected. When the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained, thereby ensuring the dynamic control of the time synchronization status and being compatible with the subsequent control of the clock drift rate, achieving overall compatibility with environmental changes or system parameter changes, and ensuring the accuracy of time synchronization of multiple sensors in the new train positioning system. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0061] Figure 1 It is a flow chart of a method for time synchronization of multiple sensors in a novel train positioning system in an embodiment of the present invention;

[0062] Figure 2 This is a flow chart of S11 in a time synchronization method for multiple sensors in a novel train positioning system in an embodiment of the present invention;

[0063] Figure 3 This is a flow chart of S12 in a time synchronization method for multiple sensors in a novel train positioning system in an embodiment of the present invention;

[0064] Figure 4 This is a flow chart of S13 in a time synchronization method for multiple sensors in a novel train positioning system in an embodiment of the present invention;

[0065] Figure 5 is a flow chart of S14 in a time synchronization method for multiple sensors in a novel train positioning system in an embodiment of the present invention;

[0066] Figure 6 This is a flow chart of S15 in a time synchronization method for multiple sensors in a novel train positioning system in an embodiment of the present invention;

[0067] Figure 7 This is a flow chart of S16 in a time synchronization method for multiple sensors in a novel train positioning system in an embodiment of the present invention;

[0068] Figure 8 It is a schematic diagram of the structure of a time synchronization system for multiple sensors in a novel train positioning system in an embodiment of the present invention;

[0069] Fig. 9 The figure is a hardware diagram of an electronic device according to an exemplary embodiment.

[0070] Fig.10 It is a schematic diagram of distance measurement in a time synchronization method for multiple sensors in a novel train positioning system in an embodiment of the present invention. DETAILED DESCRIPTION

[0071] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0072] See also Figures 1 to 10 A time synchronization method for multiple sensors in a novel train positioning system is applied to a time synchronization scenario of multiple sensors in a novel train positioning system; the time synchronization method for multiple sensors in a novel train positioning system includes:

[0073] Step S11: collecting the master clock and initializing the configuration of the ultra-wideband module, laser radar, inertial measurement unit and millimeter wave radar;

[0074] Step S12: collecting corresponding delay information based on the ranging of the ultra-wideband module;

[0075] Step S13: triggering the allocation of timestamps for the ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar according to the master clock;

[0076] Step S14: collecting the delay time between the ultra-wideband module, the laser radar, the inertial measurement unit, the millimeter-wave radar and the central processor;

[0077] Step S15: estimating the clock drift rates of the ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar based on the delay time, and dynamically supplementing the clock drift rates;

[0078] Step S16: During the operation of the train, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is collected; when the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained.

[0079] In an embodiment of the present invention, through the method in the embodiment of the present invention, the master clock is collected, and the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are initialized and configured; the corresponding delay information is collected based on the ranging of the ultra-wideband module; the allocation of timestamps of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is triggered according to the master clock; the delay time between the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar and the central processor is collected, the delay time is introduced, and the delay time is further controlled, and at the same time, the allocation of timestamps of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is realized.

[0080] Furthermore, the clock drift rates of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are estimated based on the delay time, and the clock drift rates are dynamically supplemented. During the operation of the train, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is collected. When the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained, thereby ensuring the dynamic control of the time synchronization status and being compatible with the subsequent control of the clock drift rate, achieving overall compatibility with environmental changes or system parameter changes, and ensuring the accuracy of time synchronization of multiple sensors in the new train positioning system.

[0081] refer to Figure 2 , in step S11, the master clock is collected, and the ultra-wideband module, laser radar, inertial measurement unit and millimeter wave radar are initialized and configured;

[0082] In the specific implementation process of the present invention, the specific steps may be:

[0083] S111: satellite timing system;

[0084] S112: using the clock corresponding to the satellite timing system as the master clock to collect the master clock;

[0085] S113: Associate the master clock, ultra-wideband module, lidar, inertial measurement unit and millimeter wave radar;

[0086] S114: trigger corresponding configuration based on master clock, ultra-wideband module, lidar, inertial measurement unit and millimeter wave radar;

[0087] S115: Initialize and configure the ultra-wideband module, laser radar, inertial measurement unit, and millimeter wave radar;

[0088] S116: Matching corresponding working parameters according to the initialization configuration of the ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar.

[0089] In an embodiment of the present application, a satellite timing system is collected; based on the clock corresponding to the satellite timing system as the master clock, the master clock is collected, the master clock is introduced, and subsequent management and control are performed on the master clock.

[0090] Furthermore, the master clock, ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar are associated; the corresponding configuration is triggered based on the master clock, ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar; the ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar are initialized and configured, and the initialization configuration of the ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar is realized, so as to facilitate the initialization configuration of the ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar for zero control. At the same time, the corresponding working parameters are matched according to the initialization configuration of the ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar.

[0091] At this time, a high-precision satellite timing system (such as GPS or BeiDou) is selected as the master clock to provide a unified time reference for the entire system. Initialize and configure the ultra-wideband module, inertial measurement unit, lidar, and millimeter-wave radar, and set working parameters.

[0092] refer to Figure 3 , in step S12, corresponding delay information is collected based on the ranging of the ultra-wideband module;

[0093] In the specific implementation process of the present invention, the specific steps may be:

[0094] S121: collecting data from an ultra-wideband module on the train and multiple ultra-wideband modules on the trackside;

[0095] S122: Communicate with the ultra-wideband module on the train and multiple ultra-wideband modules on the trackside, and record corresponding communication signals;

[0096] S123: defining a corresponding propagation time according to analysis of the communication signal;

[0097] S124: defining corresponding delay information according to the propagation time and the ranging of the ultra-wideband module;

[0098] S125: Collect corresponding delay information. At this time, trigger corresponding information processing based on the delay information.

[0099] In an embodiment of the present application, an ultra-wideband module on a train and multiple ultra-wideband modules on the trackside are collected, an ultra-wideband module on a train and multiple ultra-wideband modules on the trackside are introduced, and multiple interactions are performed on the ultra-wideband module on the train and multiple ultra-wideband modules on the trackside.

[0100] At this time, the ultra-wideband module on the train and multiple ultra-wideband modules on the trackside communicate, and the corresponding communication signals are recorded; the corresponding propagation time is defined based on the analysis of the communication signal; the corresponding delay information is defined based on the propagation time and the ranging of the ultra-wideband module, which is compatible with the propagation time and the ranging of the ultra-wideband module, ensuring the accuracy of the delay information. At the same time, the corresponding delay information is collected, and at this time, the corresponding information processing is triggered for the delay information.

[0101] At the same time, after unified timing, the UWB module sends out ranging information. The starting time of ranging at this time is recorded as Tmaster. The ranging data packet 1 is sent to multiple UWB modules on the trackside. After being processed by the UWB module on the trackside, the processed ranging data packet 2 and confirmation information are fed back to the UWB module. After receiving the data packet and confirmation information, the UWB module sends confirmation information to multiple UWB modules on the trackside. At this time, the first ranging is completed.

[0102] At the beginning of the second ranging, the UWB module sends ranging data packet 2 to multiple UWB modules on the trackside. After processing the data, the multiple UWB modules on the trackside send confirmation information, processed data packet 2, and the time delay information t between the start of the first ranging and the first ranging return to the vehicle-mounted UWB module. UWB_offset , each sensor makes corrections based on this delay information to re-ensure time synchronization. The UWB module then sends confirmation information to multiple UWB modules on the trackside to complete the second ranging. The train repeats this process throughout its operation to ensure time synchronization of each sensor.

[0103] refer to Figure 4 , in step S13, the allocation of timestamps of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar is triggered according to the master clock;

[0104] In the specific implementation process of the present invention, the specific steps may be:

[0105] S131: freeze master clock;

[0106] S132: Associates the master clock with the ultra-wideband module, lidar, inertial measurement unit, and millimeter-wave radar;

[0107] S133: triggering allocation of corresponding timestamps according to the master clock and the ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar;

[0108] S134: Define the corresponding timestamp of the ultra-wideband module, the timestamp of the laser radar, the timestamp of the inertial measurement unit and the timestamp of the millimeter-wave radar according to the allocation of the timestamp.

[0109] In an embodiment of the present application, a master clock is frozen; the master clock and an ultra-wideband module, a lidar, an inertial measurement unit and a millimeter-wave radar are associated, and the master clock and an ultra-wideband module, a lidar, an inertial measurement unit and a millimeter-wave radar are introduced to control the master clock and the ultra-wideband module, the lidar, the inertial measurement unit and the millimeter-wave radar as a whole.

[0110] Therefore, the allocation of corresponding timestamps is triggered according to the master clock and the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar; the corresponding timestamp of the ultra-wideband module, the timestamp of the lidar, the timestamp of the inertial measurement unit and the timestamp of the millimeter-wave radar are defined according to the allocation of the timestamp, and the timestamp of the ultra-wideband module, the timestamp of the lidar, the timestamp of the inertial measurement unit and the timestamp of the millimeter-wave radar are introduced.

[0111] For the allocation of timestamps:

[0112] (1) Assign an accurate timestamp based on the master clock to each TOA ranging delay information collected by the ultra-wideband module, denoted as T UWB =T master +t UWB_offset +Δt_UWB, where T master is the master clock time, t UWB_offset is the fixed offset of the UWB module relative to the master clock, and Δt_UWB is the random time deviation of the data collected by the UWB module this time.

[0113] (2) When Lidar collects data, the timestamp is T Lidar =T master +t Lidar_offset +Δt_lidar, where t Lidar_offset Δt_lidar is the fixed offset relative to the master clock and the random time deviation of the Lidar data collected this time.

[0114] (3) When the inertial measurement unit collects data, the timestamp is T IMU =T master +t IMU_offset +Δt_IMU, where t IMU_offset is the fixed offset of the inertial measurement unit relative to the master clock, and Δt_IMU is the random time deviation of the data collected by the inertial measurement unit this time.

[0115] (4) When the millimeter wave radar collects data, the timestamp is T mmWave =T master +t mmWave_offset +Δt_mmWave, where t mmWave_offsetis the fixed offset of the millimeter-wave radar relative to the master clock, and Δt_mmWave is the random time deviation of the millimeter-wave radar's data collection this time.

[0116] refer to Figure 5 ,S14: collect the delay time between the ultra-wideband module, lidar, inertial measurement unit, millimeter-wave radar and the central processor;

[0117] In the specific implementation process of the present invention, the specific steps may be:

[0118] S141: freeze-frame ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar;

[0119] S142: The ultra-wideband module, lidar, inertial measurement unit, and millimeter-wave radar interact with the central processor respectively;

[0120] S143: The ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar transmit the data with the timestamp to the central processing unit through the high-speed communication link, and the central processing unit caches the data after receiving it;

[0121] S144: Calculate the time difference between the laser radar, the inertial measurement unit, and the millimeter wave radar based on the time stamp of the ultra-wideband module, and adjust the corresponding time stamps according to the time difference between the laser radar, the inertial measurement unit, and the millimeter wave radar;

[0122] S145: The ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar interact with the central processor, and the delay time of the communication link between the ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar and the central processor is measured.

[0123] In an embodiment of the present application, a master clock is collected, and the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are initialized and configured; corresponding delay information is collected based on the ranging of the ultra-wideband module; the allocation of timestamps of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is triggered according to the master clock; the delay time between the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar and the central processor is collected, the delay time is introduced, and the delay time is further controlled, and at the same time, the allocation of timestamps of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is realized.

[0124] At this time, the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are frozen; the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar interact with the central processing unit respectively; the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar transmit the data with timestamps to the central processing unit through a high-speed communication link, and the central processing unit caches the data after receiving it, thereby realizing the storage of the corresponding data.

[0125] Therefore, based on the timestamp of the ultra-wideband module, the time difference of the lidar, inertial measurement unit and millimeter-wave radar is calculated, and the corresponding timestamp is adjusted according to the time difference of the lidar, inertial measurement unit and millimeter-wave radar; the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar interact with the central processing unit, and the delay time of the communication link between the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar and the central processing unit is measured, and the delay time is introduced to realize the control of the delay time.

[0126] refer to Figure 6 , S15: estimating the clock drift rates of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar based on the delay time, and dynamically supplementing the clock drift rates;

[0127] In the specific implementation process of the present invention, the specific steps may be:

[0128] S151: freeze the delay time;

[0129] S152: estimating clock drift rates of the ultra-wideband module, the laser radar, the inertial measurement unit, and the millimeter-wave radar based on the delay time;

[0130] S153: Matching a corresponding drift amount according to the clock drift rate;

[0131] S154: Dynamically compensate according to the drift amount, the timestamp of the ultra-wideband module, the timestamp of the lidar, the timestamp of the inertial measurement unit, and the timestamp of the millimeter-wave radar to dynamically supplement the clock drift rate.

[0132] In an embodiment of the present application, the delay time is frozen; and the clock drift rates of the ultra-wideband module, lidar, inertial measurement unit, and millimeter-wave radar are estimated based on the delay time, thereby realizing the estimation of the clock drift rates of the ultra-wideband module, lidar, inertial measurement unit, and millimeter-wave radar, so as to facilitate further processing of the clock drift rates of the ultra-wideband module, lidar, inertial measurement unit, and millimeter-wave radar.

[0133] Therefore, the corresponding drift amount is matched according to the clock drift rate; dynamic compensation is performed according to the drift amount, the timestamp of the ultra-wideband module, the timestamp of the lidar, the timestamp of the inertial measurement unit and the timestamp of the millimeter-wave radar to dynamically supplement the clock drift rate, thereby realizing dynamic control of the clock drift rate.

[0134] refer to Figure 7 , S16: During the operation of the train, the time synchronization status of the ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar is collected; when the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar is dynamically maintained;

[0135] In the specific implementation process of the present invention, the specific steps may be:

[0136] S161: Real-time monitoring of the dynamic operation of trains;

[0137] S162: During the operation of the train, the compensation values ​​of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter wave radar are collected;

[0138] S163: Implement corresponding dynamic adjustment based on the compensation amount of the ultra-wideband module, laser radar, inertial measurement unit and millimeter wave radar;

[0139] S164: Real-time monitoring of environmental changes or system parameters;

[0140] S165: Dynamically maintain the time synchronization state of the ultra-wideband module, lidar, inertial measurement unit and millimeter wave radar when the environment changes or system parameters change.

[0141] In the specific implementation process of the present invention, the clock drift rate of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is estimated based on the delay time, and the clock drift rate is dynamically supplemented; during the operation of the train, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is collected; when the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained, thereby ensuring the dynamic control of the time synchronization status, being compatible with the subsequent control of the clock drift rate, achieving overall compatibility with environmental changes or system parameter changes, and ensuring the accuracy of time synchronization of multiple sensors in the new train positioning system.

[0142] At this time, the dynamic operation of the train is monitored in real time; during the operation of the train, the compensation amounts of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are collected; corresponding dynamic adjustments are made based on the compensation amounts of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar, thereby realizing dynamic compensation of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar.

[0143] Therefore, environmental changes or system parameters are monitored in real time. When the environment or system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained, ensuring the dynamic control of the time synchronization status and compatibility with the subsequent control of the clock drift rate, achieving overall compatibility with environmental changes or system parameter changes, and ensuring the accuracy of time synchronization of multiple sensors in the new train positioning system.

[0144] The synchronization algorithm is introduced, taking the timestamp of the ultra-wideband module as the benchmark, assuming the timestamp of the ultra-wideband module is T UWB , the timestamp of Lidar is T Lidar , then the time difference is:

[0145] ΔT Lidar =T Lidar -T UWB

[0146] =(t lidar_offset -t UWB_offsett )+(Δt_ lidar -Δt_UWB) adjusts the timestamp of Lidar data:

[0147]

[0148] For the inertial measurement unit, let its timestamp be T IMU , then the time difference is:

[0149] ΔT IMU =T IMU -T UWB =(t IMU_offset -t UWB_offsett )+(Δt_ IMU -Δt_UWB)

[0150] Adjust the timestamps of the IMU data:

[0151] T IMU_synced =T UWB +ΔT IMU

[0152] For millimeter wave radar, let its timestamp be T mmWave , the time difference is:

[0153] ΔT mmWave =T mmWave -T UWB

[0154] =(t mmWave_offset -t UWB_offset )+(Δt_ mmWave -Δt_UWB) adjusts the timestamp of the millimeter wave radar data:

[0155] T mmWave_synced =T UWB +ΔT mmWave

[0156] In addition, communication delay error analysis and compensation are performed to measure the delay time of the communication link between each sensor and the central processing unit, which is denoted as t delay_sensor (where sensor represents Lidar, inertial measurement unit or millimeter wave radar).

[0157] Since standard time synchronization protocols such as NTP and 1588 assume that the uplink and downlink delays of the communication link are equal when calculating the communication link delay, and design algorithms based on this to eliminate the delay of the communication network to achieve the purpose of time synchronization, but in actual situations this assumption is not always true, so a method based on one-way delay measurement is designed to achieve time synchronization. A set of sensor communication link delay compensation clocks are deployed in the central processing unit network node. The clock is synchronized with the Beidou / GPS satellite clock to obtain a high-precision clock. Every fixed period T Cycle Trigger an event n , send the standard timestamp T when the event occurs to all sensor nodes n And the corresponding serial number S n After each sensor node receives the synchronization message, it synchronizes it with its own system timestamp T n′ Compare and calculate the delay compensation time t of each communication link delay_sensor =T n′ -T n Each sensor node is based on the same clock source, and only the one-way delay value t needs to be calculated. delay_sensor The communication link delay of each sensor can be eliminated, thus obtaining the compensated T Sensor_compensated .

[0158] (1) Compensate the Lidar data. The timestamp after compensation is:

[0159]

[0160] (2) Compensate the inertial measurement unit data, and the timestamp after compensation is:

[0161] T IMU_compensated=T IMU_synced -t delay_IMU

[0162] (3) Compensate the millimeter-wave radar data, and the timestamp after compensation is:

[0163] T mmWave_compensated =T mmWave_synced -t delay_mmWave

[0164] Clock drift error analysis and compensation, estimate the clock drift rate of each sensor, denoted as r sensor (where sensor represents Lidar, inertial measurement unit or millimeter wave radar). After time t, the drift amount is d sensor =r sensor ×t.

[0165] (1) Compensate the lidar data. The timestamp after compensation is:

[0166] T Lidar_final =T Lidar_compensated -d

[0167] At the same time, during the operation of the train, the communication link delay compensation clock continuously monitors the time synchronization status of each sensor, so that each sensor node uploads its own t delay_sensor The clock will be based on the sensor ID or IP address according to the t reported in the previous few cycles. delay_sensor Data smoothing removes jitter and pre-deducts the standard time before sending it to each sensor node, so that each sensor node can dynamically maintain a globally unified time when recording logs, rather than making post-adjustments based on delay information in the final data statistics and processing. When the environment changes or system parameters change, the parameters of the time synchronization algorithm are dynamically adjusted to ensure the accuracy and stability of the positioning system time synchronization.

[0168] In an embodiment of the present invention, through the method in the embodiment of the present invention, the master clock is collected, and the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are initialized and configured; the corresponding delay information is collected based on the ranging of the ultra-wideband module; the allocation of timestamps of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is triggered according to the master clock; the delay time between the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar and the central processor is collected, the delay time is introduced, and the delay time is further controlled, and at the same time, the allocation of timestamps of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is realized.

[0169] Furthermore, the clock drift rates of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are estimated based on the delay time, and the clock drift rates are dynamically supplemented. During the operation of the train, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is collected. When the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained, thereby ensuring the dynamic control of the time synchronization status and being compatible with the subsequent control of the clock drift rate, achieving overall compatibility with environmental changes or system parameter changes, and ensuring the accuracy of time synchronization of multiple sensors in the new train positioning system.

[0170] At the same time, the standard time is deducted in advance before being sent to each sensor node, so that the moment when each sensor node records the log can dynamically maintain a global unified time, instead of making post-adjustments based on delay information in the final data statistics and processing stage.

[0171] See also Figure 8 , Figure 8 It is a schematic diagram of the structural composition of a time synchronization system of multiple sensors in a novel train positioning system in an embodiment of the present invention.

[0172] like Figure 8 As shown, a time synchronization system for multiple sensors in a novel train positioning system, the time synchronization system for multiple sensors in the novel train positioning system includes:

[0173] The acquisition module 21 is used to acquire the master clock and initialize the configuration of the ultra-wideband module, laser radar, inertial measurement unit and millimeter wave radar;

[0174] The delay module 22 is used to collect corresponding delay information based on the ranging of the ultra-wideband module;

[0175] A timestamp module 23, used to trigger the allocation of timestamps for the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar according to the master clock;

[0176] The delay time module 24 is used to collect the delay time between the ultra-wideband module, the laser radar, the inertial measurement unit, the millimeter-wave radar and the central processor;

[0177] A clock drift rate module 25, for estimating the clock drift rates of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter wave radar based on the delay time, and dynamically supplementing the clock drift rates;

[0178] The time synchronization module 26 is used to collect the time synchronization status of the ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar during the operation of the train; when the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, laser radar, inertial measurement unit and millimeter-wave radar is dynamically maintained.

[0179] See also Fig. 9 , refer to the following Fig. 9 The electronic device 40 according to this embodiment of the present invention will be described. Fig. 9 The electronic device 40 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0180] like Fig. 9 As shown, the electronic device 40 is in the form of a general computing device. The components of the electronic device 40 may include but are not limited to: at least one processing unit 41, at least one storage unit 42, and a bus 43 connecting different system components (including the storage unit 42 and the processing unit 41).

[0181] The storage unit stores program codes, which can be executed by the processing unit 41, so that the processing unit 41 executes the steps according to various exemplary embodiments of the present invention described in the above “Embodiment Method” section of this specification.

[0182] The storage unit 42 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 421 and / or a cache memory unit 422 , and may further include a read-only memory unit (ROM) 423 .

[0183] The storage unit 42 may also include a program / utility 424 having a set (at least one) of program modules 425, such program modules 425 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0184] Bus 43 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0185] The electronic device 40 may also communicate with one or more external devices (e.g., keyboards, pointing devices, Bluetooth devices, etc.), one or more devices that enable a user to interact with the electronic device 40, and / or any device that enables the electronic device 40 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 44. Furthermore, the electronic device 40 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 45. Fig. 9 As shown, the network adapter 45 communicates with other modules of the electronic device 40 via the bus 43. It should be understood that although Fig. 9 Not shown, other hardware and / or software modules may be used in conjunction with the electronic device 40, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup planning systems.

[0186] Through the description of the above implementation, it is easy for those skilled in the art to understand that the example implementation described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the implementation of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, a terminal device, or a network device, etc.) to execute the method according to the implementation of the present disclosure.

[0187] Those skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage medium can include: a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk, etc. In addition, it stores computer program instructions, and when the computer program instructions are executed by a computer, the computer executes the above method.

[0188] In addition, the above describes in detail the time synchronization method and system for multiple sensors in the new train positioning system provided by the embodiments of the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A novel time synchronization method for multiple sensors in a train positioning system, characterized in that: Applied to the time synchronization scenario of multiple sensors in the new train positioning system; The time synchronization method of multiple sensors in the novel train positioning system comprises: Collect the master clock and initialize the configuration of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar; Collecting corresponding delay information based on ranging of the ultra-wideband module; Trigger the distribution of timestamps for the UWB module, LiDAR, IMU, and MMW radar based on the master clock; Collect the delay time between the UWB module, LiDAR, IMU, and mmWave radar and the central processor; Based on the delay time, the clock drift rates of the ultra-wideband module, the lidar, the inertial measurement unit and the millimeter-wave radar are estimated, and the clock drift rates are dynamically supplemented; During the operation of the train, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is collected; when the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained.

2. The time synchronization method for multiple sensors in a novel train positioning system according to claim 1 is characterized in that: The master clock is collected and the ultra-wideband module, laser radar, inertial measurement unit and millimeter wave radar are initialized and configured, including: Acquisition satellite timing system; The clock corresponding to the satellite timing system is used as the master clock to collect the master clock; Correlate the master clock, UWB module, LiDAR, IMU and mmWave radar; Based on the master clock, ultra-wideband module, lidar, inertial measurement unit and millimeter wave radar trigger corresponding configuration; Initialize the configuration of the ultra-wideband module, lidar, inertial measurement unit, and millimeter-wave radar; The corresponding working parameters are matched according to the initialization configuration of the ultra-wideband module, laser radar, inertial measurement unit and millimeter wave radar.

3. The time synchronization method for multiple sensors in a novel train positioning system according to claim 1, characterized in that: The collecting corresponding delay information based on the ranging of the ultra-wideband module includes: Collect data from the UWB module on the train and multiple UWB modules on the trackside; Communicate with the UWB module on the train and multiple UWB modules on the trackside, and record corresponding communication signals; Defining the corresponding propagation time according to the analysis of the communication signal; Defining corresponding delay information according to the propagation time and the ranging of the ultra-wideband module; The corresponding delay information is collected, and at this time, corresponding information processing is triggered according to the delay information.

4. The time synchronization method for multiple sensors in a novel train positioning system according to claim 3 is characterized in that: The allocation of timestamps for triggering the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter wave radar according to the master clock includes: Freeze the master clock; Correlate the master clock with ultra-wideband modules, lidar, inertial measurement units and millimeter wave radars; Trigger the allocation of corresponding timestamps based on the master clock and the UWB module, LiDAR, IMU, and MMW radar; The corresponding timestamp of the ultra-wideband module, the timestamp of the laser radar, the timestamp of the inertial measurement unit and the timestamp of the millimeter-wave radar are defined according to the allocation of the timestamp.

5. The time synchronization method for multiple sensors in a novel train positioning system according to claim 4 is characterized in that: The delay time between the ultra-wideband module, laser radar, inertial measurement unit, millimeter-wave radar and the central processor is collected, including: Fixed frame ultra-wideband modules, lidar, inertial measurement units and millimeter wave radar; The UWB module, LiDAR, IMU, and mmWave radar interact with the CPU separately; The UWB module, LiDAR, IMU, and MMW radar transmit the time-stamped data to the central processing unit via a high-speed communication link, and the central processing unit caches the received data. Based on the timestamp of the ultra-wideband module, the time difference between the laser radar, the inertial measurement unit and the millimeter-wave radar is calculated, and the corresponding timestamps are adjusted according to the time difference between the laser radar, the inertial measurement unit and the millimeter-wave radar; The UWB module, LiDAR, IMU and MMW radar interact with the central processor, and measure the delay time of the communication link between the UWB module, LiDAR, IMU and MMW radar and the central processor.

6. The time synchronization method for multiple sensors in a novel train positioning system according to claim 5, characterized in that: The method of estimating the clock drift rate of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter wave radar based on the delay time and dynamically supplementing the clock drift rate includes: Freeze the delay time; estimating clock drift rates of the ultra-wideband module, the lidar, the inertial measurement unit, and the millimeter-wave radar based on the delay time; The corresponding drift amount is matched according to the clock drift rate.

7. The time synchronization method for multiple sensors in a novel train positioning system according to claim 6, characterized in that: The method of estimating the clock drift rate of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter wave radar based on the delay time and dynamically supplementing the clock drift rate also includes: Dynamic compensation is performed based on the drift amount, the timestamp of the ultra-wideband module, the timestamp of the lidar, the timestamp of the inertial measurement unit, and the timestamp of the millimeter-wave radar to dynamically supplement the clock drift rate.

8. The time synchronization method for multiple sensors in a novel train positioning system according to claim 7, characterized in that: During the operation of the train, the time synchronization state of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar is collected; when the environment changes or the system parameters change, the time synchronization state of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar is dynamically maintained, including: Real-time monitoring of the dynamic operation of trains; During the operation of the train, the compensation values ​​of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar are collected; Corresponding dynamic adjustments are made based on the compensation amounts of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar.

9. The time synchronization method for multiple sensors in a novel train positioning system according to claim 8, characterized in that: The method includes collecting the time synchronization status of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar during the operation of the train; dynamically maintaining the time synchronization status of the ultra-wideband module, the laser radar, the inertial measurement unit and the millimeter-wave radar when the environment changes or the system parameters change, and further comprising: Real-time monitoring of environmental changes or system parameters; Dynamically maintain the time synchronization state of the UWB module, LiDAR, IMU, and mmWave radar when the environment changes or system parameters change.

10. A time synchronization system for multiple sensors in a novel train positioning system, characterized in that: The time synchronization system for multiple sensors in the novel train positioning system is applied to the time synchronization method for multiple sensors in the novel train positioning system as claimed in any one of claims 1 to 9, and the time synchronization system for multiple sensors in the novel train positioning system includes: The acquisition module is used to acquire the main clock and initialize the configuration of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar; The delay module is used to collect the corresponding delay information based on the ranging of the ultra-wideband module; A timestamp module is used to trigger the allocation of timestamps for the ultra-wideband module, lidar, inertial measurement unit, and millimeter-wave radar based on the master clock; Delay time module, used to collect the delay time between the ultra-wideband module, lidar, inertial measurement unit, millimeter-wave radar and the central processor; A clock drift rate module is used to estimate the clock drift rates of the ultra-wideband module, the lidar, the inertial measurement unit and the millimeter-wave radar based on the delay time, and to dynamically supplement the clock drift rates; The time synchronization module is used to collect the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar during the operation of the train; when the environment changes or the system parameters change, the time synchronization status of the ultra-wideband module, lidar, inertial measurement unit and millimeter-wave radar is dynamically maintained.

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