Dynamic positioning precision test system for vehicle-mounted positioning equipment

Abstract

The invention provides a system for testing the dynamic positioning precision of vehicle-mounted positioning equipment, which is characterized in that at least three fixed high-precision reference position units are distributed in a scattered manner, high-precision fixed point coordinates are provided based on various satellite positioning systems, and a standard position terminal mounted on a target vehicle is adopted to receive data of the high-precision reference position units by using an antenna, so that the dynamic positioning precision of the vehicle-mounted positioning equipment is tested. And a time difference positioning method is adopted to calculate the standard coordinates of the vehicle, so that the consistency and accuracy of measurement are ensured. Based on the time synchronization unit, multiple satellite positioning systems are used for time service, high-precision time synchronization signals are provided for the whole system, and the accuracy of positioning testing is guaranteed. And the positioning precision analysis module compares the standard coordinates with the positioning coordinates of the vehicle-mounted positioning equipment, calculates errors and performs statistical analysis, and provides detailed data information for evaluation of dynamic positioning precision, so that the dynamic positioning precision of the vehicle-mounted positioning equipment can be accurately measured.

Description

Technical Field

[0001] The invention relates to the field of positioning technology, and in particular to a dynamic positioning accuracy testing system for vehicle-mounted positioning equipment. Background Art

[0002] With the implementation of the smart railway strategy, business applications based on railway mobile equipment location services are becoming increasingly widespread, especially in mobile equipment dispatching and command, train approach warning, railway comprehensive inspection, passenger and freight transportation, etc. The improvement of the dynamic positioning performance of mobile equipment has further enhanced the railway operation safety guarantee capability and promoted the improvement of railway passenger and freight transportation service quality and railway operation efficiency.

[0003] The dynamic positioning accuracy of the onboard positioning equipment of railway mobile equipment is one of the key performance parameters of railway onboard navigation and positioning equipment. The dynamic positioning accuracy directly affects the level of dynamic location service business application of mobile equipment. Railway science and technology is an applied science in the field of science and technology. The application of research results to railway practice requires testing and verification through scientific experiments.

[0004] Product testing is an important means to ensure product quality and ensure safe and reliable application. In the existing national and railway industry standards on the dynamic positioning accuracy of on-board positioning equipment, the dynamic positioning accuracy test method mainly includes laboratory simulation environment testing and high-precision standard positioning equipment comparison testing under ideal actual signal environment. Among them, the dynamic positioning accuracy test method of laboratory simulation environment testing mainly uses a satellite navigation signal simulator to broadcast simulated satellite navigation signals according to test requirements. In the simulation signal simulation parameters, the motion parameters, position parameters, and navigation signal parameters of the device under test are simulated. By comparing the positioning data returned by the device under test with the simulated position information, statistical analysis is performed to obtain the evaluation results of dynamic positioning accuracy; the high-precision standard positioning equipment comparison test under ideal actual signal environment mainly involves the device under test and the standard dynamic positioning equipment using a high-precision combined navigation and positioning system receiving actual satellite navigation signals at the same time, comparing and analyzing the positioning data at the same time, and statistical analysis is performed to obtain the evaluation results of dynamic positioning accuracy. In the above two test methods, whether in the simulated environment or the actual environment, the satellite navigation signal quality of the test environment is relatively ideal, and there is a problem that the test evaluation results do not match the actual application effects of complex application scenarios. Especially in the railway industry, the railway transportation lines are geographically large, and the natural environment, business scenarios, and line conditions of vehicle-mounted positioning applications are complex, involving railway stations, tunnels, cuttings, mountain obstructions, bridges and other special scenarios. The results of ideal test conditions cannot meet the needs of actual dynamic positioning accuracy testing. In addition, the satellite navigation signal simulation equipment and standard positioning equipment used in the two existing test methods are restricted by installation and deployment conditions, which greatly limits the scope of dynamic positioning accuracy test sites, bringing certain inconveniences to actual testing work. In addition, the equipment is expensive and the test cost is high. There is an urgent need for a convenient, low-cost, and highly reliable test method and device to meet the needs of dynamic positioning accuracy testing of railway vehicle-mounted positioning equipment. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a vehicle-mounted positioning device dynamic positioning accuracy testing system to eliminate or improve one or more defects existing in the prior art and solve the problem that the prior art cannot efficiently, accurately and cost-effectively test the dynamic positioning accuracy of the vehicle-mounted positioning device.

[0006] The present invention provides a dynamic positioning accuracy testing system for a vehicle-mounted positioning device, the system comprising:

[0007] At least three fixed high-precision reference position units, each of which is arranged at a dispersed fixed point, and the fixed point coordinate data of the fixed high-precision reference position units are obtained based on one or more of a plurality of satellite positioning systems;

[0008] A standard position terminal is arranged on the target vehicle and maintains a preset relative position with the vehicle-mounted positioning device to be tested; the standard position terminal obtains the fixed point coordinate data of at least three of the fixed high-precision reference position units through a receiving antenna, and calculates the current standard coordinates of the standard position terminal based on time difference positioning;

[0009] A time synchronization unit that provides time synchronization based on one or more of a variety of satellite positioning systems and provides synchronization signals;

[0010] A test terminal data interface, connected to the standard position terminal, the time synchronization unit and the vehicle-mounted positioning device to be tested; the test terminal data interface is used to obtain the synchronization signal of the time synchronization unit, and obtain the standard coordinates of the standard position terminal at the same time point and the positioning coordinates to be analyzed independently collected by the vehicle-mounted positioning device to be tested based on the synchronization signal;

[0011] The positioning accuracy analysis module is used to calculate the error of the positioning coordinates to be analyzed by combining the preset relative position and the standard coordinates, and to statistically analyze the dynamic positioning accuracy of the vehicle-mounted positioning device to be tested.

[0012] In some embodiments, the fixed high-precision reference position unit includes: a satellite navigation signal receiving antenna, a satellite positioning unit, a high-precision rubidium clock unit, and a time synchronization signal input and output interface;

[0013] The satellite navigation signal receiving antenna is a multi-band receiving antenna, which is used to support the reception of Beidou satellite positioning signals, GPS positioning signals, Galileo positioning signals and / or GLONASS positioning signals;

[0014] The satellite positioning unit includes: a Beidou satellite positioning module, a GPS positioning module, a Galileo positioning module and / or a GLONASS positioning module;

[0015] The satellite positioning unit selects one of the Beidou satellite positioning module, the GPS positioning module, the Galileo positioning module and / or the GLONASS positioning module to perform positioning based on signal strength to obtain the fixed point coordinate data;

[0016] Alternatively, the satellite positioning unit optimizes the fixed point coordinate data respectively acquired by the Beidou satellite positioning module, the GPS positioning module, the Galileo positioning module and / or the GLONASS positioning module in a weighted average form.

[0017] In some embodiments, the time synchronization unit includes:

[0018] Beidou satellite navigation signal receiving antenna, used to receive the time signal of Beidou satellite;

[0019] Beidou timing receiver module, used to demodulate the received time signal, parse out the time information, and provide accurate time mark;

[0020] High-precision rubidium clock unit, used to perform time calibration after receiving Beidou time signals and maintain a stable internal clock;

[0021] Time synchronization signal output interface, used to distribute the calibrated time to other devices;

[0022] Alternatively, the time synchronization unit further configures a plurality of high-precision clock sources to construct redundant backup clocks, and the high-precision clock sources include cesium clocks or GPS clocks.

[0023] In some embodiments, the high-precision rubidium clock unit is further provided with a temperature sensor and a frequency adjustment unit;

[0024] The temperature sensor is used to collect the current ambient temperature in real time;

[0025] The frequency adjustment unit is used to establish a relationship model between temperature and frequency drift through a linear regression or polynomial fitting method, calculate a frequency drift compensation value according to the relationship model and the current ambient temperature, dynamically adjust the clock frequency, and compensate for the frequency drift caused by temperature changes.

[0026] In some embodiments, the system further comprises:

[0027] A comprehensive display module, used for displaying the working status and detected parameters of the fixed high-precision reference position unit, the standard position terminal, the time synchronization unit, the test terminal data interface and the positioning accuracy analysis module in real time;

[0028] A parameter configuration module, used to initialize and adjust the operating parameters of the fixed high-precision reference position unit, the standard position terminal, the time synchronization unit, the test terminal data interface and the positioning accuracy analysis module;

[0029] A test control module, used to control the initiation, stop, process control and abnormal alarm of the positioning accuracy detection of the vehicle-mounted positioning device to be tested;

[0030] Test data storage module, used for preprocessing, saving, deleting and recording test data;

[0031] Test data query module, used to query historical test data.

[0032] In some embodiments, the test control module is also used to query the data transmission status in the actual application environment according to the operating route of the vehicle-mounted positioning device to be tested, and configure a simulated test environment with similar data transmission status to detect the system; the data transmission status includes data integrity rate, cycle slip ratio, multipath error value and carrier-to-noise ratio.

[0033] In some embodiments, the standard position terminal calculates the standard coordinates using the following formula:

[0034]

[0035] Among them, (x1, y1, z1) is the fixed point coordinate data of the first fixed high-precision reference location unit, (x2, y2, z2) is the fixed point coordinate data of the second fixed high-precision reference location unit, and (x3, y3, z3) is the fixed point coordinate data of the third fixed high-precision reference location unit; T1 is the time when the first fixed high-precision reference location unit transmits the model, T2 is the time when the second fixed high-precision reference location unit transmits the model, and T3 is the time when the third fixed high-precision reference location unit transmits the model; T is the time when the data of the first fixed high-precision reference location unit, the second fixed high-precision reference location unit and the third fixed high-precision reference location unit are received; δt is the delay of the signal in the hardware transceiver channel.

[0036] In some embodiments, the system is further provided with a standard accuracy correction unit for optimizing the estimation of the standard coordinates based on an extended Kalman filter, comprising:

[0037] Setting the initial state of the standard position terminal and its error covariance matrix, wherein the initial state includes position and speed;

[0038] Use the motion model to predict the state and error covariance at the next moment, and update the error;

[0039] Calculating a Kalman gain based on the predicted error covariance and current observation data to balance the influence of the predicted data and the observation data;

[0040] In combination with the observation data, the predicted state is adjusted to obtain the precise position of the standard location terminal;

[0041] updating the state and the error covariance to reflect the new estimated accuracy;

[0042] Repeat the above steps.

[0043] In some embodiments, the integrated display module is also used to associate the standard coordinates with a railway electronic map and display them visually.

[0044] In some embodiments, the positioning accuracy analysis module calculates the Euclidean distance, root mean square error or mean absolute error between the standard coordinates and the positioning coordinates to be analyzed as the positioning accuracy, and displays and visualizes it based on the Grafana platform.

[0045] The beneficial effects of the present invention are at least:

[0046] The dynamic positioning accuracy test system for the vehicle-mounted positioning device of the present invention provides high-precision fixed point coordinates based on multiple satellite positioning systems through the dispersed layout of at least three fixed high-precision reference position units, and adopts a standard position terminal installed on the target vehicle to receive the data of the high-precision reference position unit using an antenna, and adopts a time difference positioning method to calculate the standard coordinates of the vehicle to ensure the consistency and accuracy of the measurement. Based on the time synchronization unit, multiple satellite positioning systems are used for timing, providing a high-precision time synchronization signal for the entire system, thereby ensuring the accuracy of the positioning test. The positioning accuracy analysis module compares the standard coordinates with the positioning coordinates of the vehicle-mounted positioning device, calculates the error and performs statistical analysis, and provides detailed data information for the evaluation of dynamic positioning accuracy, thereby being able to accurately measure the dynamic positioning accuracy of the vehicle-mounted positioning device.

[0047] Furthermore, the present application combines multiple positioning systems to jointly detect the positioning coordinates of fixed points, and optimizes them through weighted averaging, which can improve accuracy.

[0048] Furthermore, by providing a temperature sensor and a frequency adjustment unit, the frequency drift compensation of the clock frequency is performed based on the change of the ambient temperature, thereby ensuring the accuracy of the positioning of each part in the system described in the present application.

[0049] Furthermore, the present application provides a simulated test environment by querying the data transmission status of the vehicle-mounted positioning device to be tested in the actual operating line, which can improve the integrity of the test and meet the needs of more scenarios.

[0050] Furthermore, the standard position terminal uses the time difference positioning method to calculate the current standard coordinates with the help of at least three fixed point coordinate data, which can improve the positioning accuracy of the standard coordinates and improve the detection effect of the dynamic positioning accuracy of the vehicle-mounted positioning equipment.

[0051] Furthermore, the present application optimizes the standard coordinates of the standard position terminal based on the extended Kalman filter, which can improve the detection effect of the dynamic positioning accuracy of the vehicle-mounted positioning equipment.

[0052] Additional advantages, purposes, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The purposes and other advantages of the present invention may be achieved and obtained by the structures specifically indicated in the specification and the accompanying drawings.

[0053] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute a limitation of the present invention. In the drawings:

[0055] Figure 1 It is a structural schematic diagram of a dynamic positioning accuracy testing system for a vehicle-mounted positioning device according to an embodiment of the present invention.

[0056] Figure 2 The figure is a schematic diagram of the deployment relationship of various structures in the dynamic positioning accuracy test system of the vehicle-mounted positioning equipment according to one embodiment of the present invention.

[0057] Figure 3 The figure is a working logic diagram of a dynamic positioning accuracy testing system for a vehicle-mounted positioning device according to an embodiment of the present invention.

[0058] Figure 4 The figure is a schematic diagram of the structure of an integrated antenna component of a dynamic positioning accuracy test system for a vehicle-mounted positioning device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0060] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0061] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0062] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection involving an intermediate.

[0063] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0064] The present invention provides a dynamic positioning accuracy test scheme for railway vehicle-mounted positioning equipment based on time difference positioning combined with map matching positioning technology. By combining time synchronization technology, time difference positioning technology, Beidou positioning technology, electronic map technology, mathematical statistical analysis technology and dynamic positioning accuracy test technology, after the railway vehicle-mounted positioning equipment and a test terminal complete high-precision time synchronization through a time synchronization unit, the dynamic positioning absolute coordinates of the measured positioning equipment at the same time and the standard coordinates of the test terminal itself based on the time difference positioning + map matching positioning technology are compared, calculated and statistically analyzed, the dynamic positioning error of the measured positioning equipment can be obtained in real time, and the dynamic positioning accuracy of the measured positioning equipment is evaluated based on the positioning error data statistics, which is more in line with the actual application scenario of the railway vehicle-mounted positioning equipment, can more truly reflect the dynamic positioning accuracy of the measured equipment in the actual railway application, and the test result is more scientific and accurate.

[0065] Specifically, the present invention provides a vehicle-mounted positioning equipment dynamic positioning accuracy testing system, such as Figure 1 and 3 As shown, the system includes: a fixed high-precision reference position unit, a standard position terminal, a time synchronization unit, a test terminal data interface and a positioning accuracy analysis module.

[0066] At least three fixed high-precision reference position units are set up, and the fixed high-precision reference position units are respectively set at dispersed fixed points, and the fixed point coordinate data of the fixed high-precision reference position units are obtained based on one or more of a variety of satellite positioning systems. Each set of fixed high-precision reference position units is composed of a Beidou satellite navigation signal receiving antenna, a Beidou measurement positioning unit, a high-precision rubidium clock unit, a time synchronization signal input and output interface, etc. It obtains high-precision position data through satellite positioning post-processing and supports high-precision position data transmission function. At the same time, the fixed high-precision reference position unit has a remote configuration function, which can realize the remote startup, initialization, parameter configuration and other functions of the fixed high-precision reference position unit at the test site.

[0067] The data protocol of the signal transmitted by the fixed high-precision reference location unit includes the fixed high-precision reference location unit serial number, longitude, latitude, altitude, and signal transmission time. According to the requirements of meter-level positioning accuracy of vehicle-mounted positioning, the signal transmission time information is accurate to nanoseconds, that is, the time information format is YYYY-MM-DD HH:MM:ss.sssssssss, which represents year / month / day / hour / minute / second / millisecond / microsecond / nanosecond respectively.

[0068] In some embodiments, the fixed high-precision reference position unit includes: a satellite navigation signal receiving antenna, a satellite positioning unit, a high-precision rubidium clock unit, and a time synchronization signal input and output interface.

[0069] The satellite navigation signal receiving antenna is a multi-band receiving antenna, which is used to support the reception of Beidou satellite positioning signals, GPS positioning signals, Galileo positioning signals and / or GLONASS positioning signals. The satellite positioning unit includes: Beidou satellite positioning module, GPS positioning module, Galileo positioning module and / or GLONASS positioning module. The satellite positioning unit selects one of the Beidou satellite positioning module, GPS positioning module, Galileo positioning module and / or GLONASS positioning module based on the signal strength to perform positioning and obtain fixed point coordinate data; or, the satellite positioning unit optimizes the fixed point coordinate data respectively obtained by the Beidou satellite positioning module, GPS positioning module, Galileo positioning module and / or GLONASS positioning module in the form of weighted average.

[0070] The standard position terminal is set on the target vehicle and maintains a preset relative position with the vehicle-mounted positioning device to be tested; the standard position terminal obtains the fixed point coordinate data of at least three of the fixed high-precision reference position units through the receiving antenna, and calculates the current standard coordinates of the standard position terminal based on the time difference positioning. Since multiple fixed high-precision reference position units can be set, three of them in a triangular distribution can be used for time difference positioning calculation during each positioning process of the standard position terminal.

[0071] Specifically, Figure 2As shown, before the test, the fixed high-precision reference position units 1, 2, and 3 are installed at fixed points dispersed at a certain distance. The three points can be arranged in a triangle according to the test requirements. The precise position coordinates of each reference position unit are calculated based on the post-processing algorithm of the year-round positioning system (GNSS) through the ground-based enhanced service of the railway Beidou application service platform. The coordinates are set to be (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3). The standard position terminal is installed on the railway test mobile equipment. The standard position terminal receives the fixed high-precision reference position unit 1 and the fixed high-precision reference position unit 3 at the same time at time T. The signals transmitted by the reference position unit 2 and the fixed high-precision reference position unit 3 are T1, T2, and T3 respectively. To ensure the test accuracy, the fixed high-precision reference position units use Beidou satellite timing, which is used for field applications after unified high-precision time synchronization through the time synchronization unit. At the same time, to ensure the accuracy of time synchronization and reduce the time error caused by the transmission path, the signal receiving channel of the standard position terminal is calibrated for transmission delay, and δt is the delay of the signal in the hardware transceiver channel.

[0072] Specifically, the calculation formula for calculating the standard coordinates of the standard position terminal is:

[0073]

[0074] Among them, (x1, y1, z1) is the fixed point coordinate data of the first fixed high-precision reference location unit, (x2, y2, z2) is the fixed point coordinate data of the second fixed high-precision reference location unit, and (x3, y3, z3) is the fixed point coordinate data of the third fixed high-precision reference location unit; T1 is the time when the first fixed high-precision reference location unit transmits the model, T2 is the time when the second fixed high-precision reference location unit transmits the model, and T3 is the time when the third fixed high-precision reference location unit transmits the model; T is the time when data from the first fixed high-precision reference location unit, the second fixed high-precision reference location unit and the third fixed high-precision reference location unit are received; δt is the delay of the signal in the hardware transceiver channel.

[0075] The time synchronization unit performs timing based on one or more of a variety of satellite positioning systems and provides synchronization signals. In some embodiments, the time synchronization unit includes: a Beidou satellite navigation signal receiving antenna, a Beidou timing receiver module, a high-precision rubidium clock unit, and a time synchronization signal output interface. Through the Beidou satellite system timing, it supports the output of time synchronization signals such as 1PPS second pulses and IRIG-B (DC), which are used for high-precision time unification and time synchronization of the equipment under test and the ground standard position unit. The Beidou satellite navigation signal receiving antenna is used to receive the time signal of the Beidou satellite; the Beidou timing receiver module is used to demodulate the received time signal, parse the time information, and provide an accurate time mark; the high-precision rubidium clock unit is used to perform time calibration after receiving the Beidou time signal and maintain a stable internal clock; the time synchronization signal output interface is used to distribute the calibrated time to other devices.

[0076] Alternatively, the time synchronization unit further configures a plurality of high-precision clock sources to construct redundant backup clocks, and the high-precision clock sources include cesium clocks or GPS clocks.

[0077] In some embodiments, the high-precision rubidium clock unit is further provided with a temperature sensor and a frequency adjustment unit. The temperature sensor is used to collect the current ambient temperature in real time. The frequency adjustment unit is used to establish a relationship model between temperature and frequency drift by linear regression or polynomial fitting, calculate the frequency drift compensation value according to the relationship model and the current ambient temperature, dynamically adjust the clock frequency, and compensate for the frequency drift caused by temperature changes.

[0078] The test terminal data interface is used to connect the standard position terminal, the time synchronization unit and the vehicle-mounted positioning device to be tested; the test terminal data interface is used to obtain the synchronization signal of the time synchronization unit, and based on the synchronization signal, obtain the standard coordinates of the standard position terminal at the same time point and the positioning coordinates to be analyzed independently collected by the vehicle-mounted positioning device to be tested.

[0079] The positioning accuracy analysis module is used to calculate the error of the positioning coordinates to be analyzed by combining the preset relative position and the standard coordinates, and statistically analyze the dynamic positioning accuracy of the vehicle-mounted positioning device to be tested. In some embodiments, the positioning accuracy analysis module calculates the Euclidean distance, root mean square error or mean absolute error between the standard coordinates and the positioning coordinates to be analyzed as the positioning accuracy, and displays and visualizes it based on the Grafana platform.

[0080] Specifically, the positioning accuracy analysis module first restores the actual position of the vehicle-mounted positioning device to be tested based on the preset relative position and standard coordinates, and then calculates the error with the positioning coordinates to be analyzed. Based on the process of the vehicle-mounted positioning device to be tested accompanying the test vehicle or train running, the positioning accuracy is dynamically detected and dynamically analyzed.

[0081] In some embodiments, the system further includes: a comprehensive display module, a parameter configuration module, a test control module, a test data storage module and a test data query module.

[0082] The integrated display module is used to display the working status and detected parameters of the fixed high-precision reference position unit, standard position terminal, time synchronization unit, test terminal data interface and positioning accuracy analysis module in real time.

[0083] The parameter configuration module is used to initialize and adjust the operating parameters of the fixed high-precision reference position unit, standard position terminal, time synchronization unit, test terminal data interface and positioning accuracy analysis module.

[0084] The test control module is used to control the initiation, stop, process control and abnormal alarm of the positioning accuracy detection of the vehicle-mounted positioning device to be tested.

[0085] The test data storage module is used to preprocess, save, delete and record test data.

[0086] The test data query module is used to query historical test data.

[0087] In some embodiments, the test control module is also used to query the data transmission status in the actual application environment according to the operating route of the vehicle-mounted positioning device to be tested, and configure a simulated test environment with similar data transmission status to detect the system; the data transmission status includes data integrity rate, cycle slip ratio, multipath error value and carrier-to-noise ratio.

[0088] The railway line test environment should be able to reflect the line conditions of the actual application scenario and have similarities with the application scenario application type, such as mountain obstruction, road cuttings, bridges, stations, etc. The test railway line environment does not have special situations such as human interference and natural interference that are not involved in the actual application scenario of the tested equipment. The selection and simulation method of the railway line test environment is to configure the satellite navigation signal acquisition terminal on site, transmit the collected original observation data to the background satellite navigation signal quality assessment system through the mobile public network and wireless network, and perform similarity matching with the actual application environment for key parameters such as data integrity rate, cycle slip ratio, multipath error value, carrier-to-noise ratio, satellite viewing angle, etc. The scene with similarity matching that meets the requirements is the selected test environment.

[0089] Environmental type refers to the business scope and application scenarios of railway Beidou applications, mainly involving roadbed, bridges, cuttings, culverts, tunnel backslope (tunnel entrance), mountain obstructions (half the sky, etc.), stations, etc.

[0090] The satellite viewing angle is the horizontal angle range of 1° to 90° for observing and receiving Beidou satellite signals. The larger the satellite viewing angle, the more conducive it is to observing more satellites and higher satellite signal quality.

[0091] The data integrity rate is the ratio of the number of epochs actually observed by the GNSS receiver to the number of epochs that should be observed theoretically under a certain sampling rate in an observation period. The maximum value of the data integrity rate is 100%. The larger the value, the more epochs the GNSS receiver actually observed in the current observation period, and the better the observation environment and operating status.

[0092]

[0093] Among them, D I is the data integrity rate; N have is the actual observed epoch number; N expt is the number of epochs that should be observed theoretically.

[0094] Multipath error value: When the GNSS receiver receives signals directly from the satellite, the reflection and refraction of the signals by nearby objects cause interference and superposition with the satellite signals, forming a synthetic signal, which causes deviations in the observed values. The smaller the multipath error value, the smaller the influence of the observation environment around the GNSS receiver on the reflection and refraction of the signals. It is generally believed that when the actual measured MP1 is greater than 0.35 and MP2 is greater than 0.45, the multipath effect on the accuracy of the observed data cannot be ignored, and the larger the multipath error value, the greater the error in the measurement result.

[0095]

[0096] MP is the multipath error value; ρ is the pseudorange observation value, and f is the carrier frequency; is the carrier phase observation; 1 and 2 represent the two band frequency indexes corresponding to the GNSS system satellites.

[0097] The carrier-to-noise ratio is the ratio of the carrier power of the navigation signal to the noise power spectral density, that is, the signal-to-noise ratio in a 1 Hz bandwidth. It is one of the signal quality indicators.

[0098]

[0099] is the ratio of the carrier power to the noise power at the receiving end; B N is the equivalent noise bandwidth, in dBHz.

[0100] The cycle slip ratio is caused by environmental occlusion or other reasons that cause the signal to lose lock, the integer cycle count of the carrier phase observation is discontinuous, and then a jump phenomenon occurs.

[0101]

[0102] o is the number of carrier observations; slps is the number of cycle slips. The cosine similarity algorithm is mainly used to evaluate the similarity matching, and the key parameters scenario type, satellite visual angle, data integrity rate, cycle slip ratio, multipath error value, and carrier-to-noise ratio are defined as the test scenario a (x1, x2, x3, x4, x5, x6) and the demand scenario β (y1, y2, y3, y4, y5, y6).

[0103]

[0104] The cosine value range is [-1,1]. Find the angle between the two vectors and get the cosine value corresponding to the angle. This cosine value can be used to characterize the similarity of the two vectors. The smaller the angle is, the closer it is to 0 degrees, and the closer the cosine value is to 1, the more consistent their directions are, and the more similar they are. When the directions of the two vectors are completely opposite, the cosine of the angle takes the minimum value of -1. When the cosine value is 0, the two vectors are orthogonal and the angle is 90 degrees. Therefore, it can be seen that the cosine similarity has nothing to do with the amplitude of the vector, but only with the direction of the vector. This patent takes into account the particularity of the dynamic positioning application of railway on-board positioning equipment. When calculating the similarity between the railway line test environment and the actual application scenario, the cosine value is taken as 0.85 or above to meet the needs of matching the actual application scenario.

[0105] In some embodiments, the system is further provided with a standard accuracy correction unit for optimizing the estimation of the standard coordinates based on the extended Kalman filter, including steps S101 to S106:

[0106] Step S101: setting the initial state of the standard position terminal and its error covariance matrix, the initial state including position and speed.

[0107] Step S102: Use the motion model to predict the state and error covariance at the next moment, and update the error.

[0108] Step S103: Based on the predicted error covariance and the current observation data, the Kalman gain is calculated to balance the influence of the predicted data and the observation data.

[0109] Step S104: Combine the observed data and adjust the predicted state to obtain the precise position of the standard location terminal.

[0110] Step S105: Update the state and error covariance to reflect the new estimation accuracy.

[0111] Step S106: Repeat the above steps.

[0112] In some embodiments, the integrated display module is also used to associate the standard coordinates with the railway electronic map and display them visually. Based on the map matching positioning technology, the standard coordinates of the standard location terminal obtained by the solution are associated with the longitude and latitude and line mileage information in the railway electronic map, so that the line mileage coordinates of the standard location terminal on the railway line can be displayed.

[0113] In the system described in the present invention, data transmission uses shortwave wireless channels to achieve spatial transmission of test data, and the frequency of the receiving and transmitting signals for wireless data transmission uses the 3-30MHz shortwave public civilian frequency band. The data of the fixed high-precision reference position unit is converted from digital to analog through a high-speed D / A conversion module to achieve conversion of the test data digital signal into an analog signal, and up-conversion is performed to achieve frequency isolation with the satellite navigation signal band to avoid signal interference; in terms of signal modulation, based on radio frequency signal modulation technology, a pseudo-random code sequence is used for frequency shift keying to transmit test data, and A / D conversion is used to achieve conversion of analog signals to digital signals and digital demodulation to achieve data communication; at the same time, identity authentication and data password protection technology are used to achieve the security of the test channel and test data.

[0114] In another embodiment, if Figure 4 As shown, an integrated antenna assembly of a dynamic positioning accuracy test system for a vehicle-mounted positioning device is constructed. The integrated antenna assembly includes an integrated antenna mounting base, a high-precision IMU device, a fixed high-precision reference position unit signal receiving antenna, a satellite navigation signal receiving antenna, and an absolute position correction unit.

[0115] In this embodiment, the test system integrates a high-precision IMU inertial measurement unit. The installation position of the IMU and the phase center of the satellite navigation signal receiving antenna, as well as the receiving antenna that receives the fixed high-precision reference position unit signal (hereinafter referred to as the receiving antenna), are installed at different heights of the same horizontal coordinate, and the height difference between the three is known. When calculating the dynamic positioning accuracy of the vehicle-mounted device under test, the three-dimensional coordinates of the actual position of the receiving antenna are calculated by receiving the fixed high-precision reference position unit signal. On this basis, the height difference between the receiving antenna and the satellite navigation signal receiving antenna is superimposed, and the positioning result of the vehicle-mounted device under test can be compared with the positioning result of the vehicle-mounted device under test to calculate the dynamic positioning accuracy of the vehicle-mounted device under test.

[0116] When the train is traveling in certain sections, such as curved lines, the train may have a certain inclination, causing the coordinate difference between the receiving antenna and the satellite navigation signal receiving antenna to change in the three directions of x, y, and z, and the amount of change is unknown, which will affect the positioning result comparison. The present invention integrates the IMU inertial measurement unit to measure the acceleration values ​​of the IMU components in the three directions of x, y, and z, respectively, and then calculate the inclination angles in the three directions. Since the receiving antenna, the satellite navigation signal receiving antenna and the IMU are all hard-connected, the inclination angles of the three are the same. Then, the distance difference between the receiving antenna and the satellite navigation signal receiving antenna in the three directions of x, y, and z can be calculated. When comparing the positioning results, by superimposing the above-calculated distance differences in the three directions of x, y, and z, the influence of the train inclination on the positioning data comparison results can be eliminated, and the real dynamic positioning accuracy of the tested vehicle-mounted equipment can be obtained.

[0117] In summary, the dynamic positioning accuracy test system for the vehicle-mounted positioning device of the present invention provides high-precision fixed point coordinates based on a variety of satellite positioning systems through the dispersed layout of at least three fixed high-precision reference position units, and adopts a standard position terminal installed on the target vehicle to receive the data of the high-precision reference position unit using an antenna, and adopts a time difference positioning method to calculate the standard coordinates of the vehicle to ensure the consistency and accuracy of the measurement. Based on the time synchronization unit, a variety of satellite positioning systems are used for timing, providing a high-precision time synchronization signal for the entire system, thereby ensuring the accuracy of the positioning test. The positioning accuracy analysis module compares the standard coordinates with the positioning coordinates of the vehicle-mounted positioning device, calculates the error and performs statistical analysis, and provides detailed data information for the evaluation of dynamic positioning accuracy, thereby being able to accurately measure the dynamic positioning accuracy of the vehicle-mounted positioning device.

[0118] Furthermore, the present application combines multiple positioning systems to jointly detect the positioning coordinates of fixed points, and optimizes them through weighted averaging, which can improve accuracy.

[0119] Furthermore, by providing a temperature sensor and a frequency adjustment unit, the frequency drift compensation of the clock frequency is performed based on the change of the ambient temperature, thereby ensuring the accuracy of the positioning of each part in the system described in the present application.

[0120] Furthermore, the present application provides a simulated test environment by querying the data transmission status of the vehicle-mounted positioning device to be tested in the actual operating line, which can improve the integrity of the test and meet the needs of more scenarios.

[0121] Furthermore, the standard position terminal uses the time difference positioning method to calculate the current standard coordinates with the help of at least three fixed point coordinate data, which can improve the positioning accuracy of the standard coordinates and improve the detection effect of the dynamic positioning accuracy of the vehicle-mounted positioning equipment.

[0122] Furthermore, the present application optimizes the standard coordinates of the standard position terminal based on the extended Kalman filter, which can improve the detection effect of the dynamic positioning accuracy of the vehicle-mounted positioning equipment.

[0123] It should be understood by those skilled in the art that the exemplary components, systems and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software or a combination of the two. Whether it is performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present invention are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link via a data signal carried in a carrier.

[0124] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0125] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0126] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dynamic positioning accuracy test system for vehicle-mounted positioning equipment, characterized in that: The system comprises: At least three fixed high-precision reference position units, each of which is arranged at a dispersed fixed point, and the fixed point coordinate data of the fixed high-precision reference position units are obtained based on one or more of a plurality of satellite positioning systems; A standard position terminal is arranged on the target vehicle and maintains a preset relative position with the vehicle-mounted positioning device to be tested; the standard position terminal obtains the fixed point coordinate data of at least three of the fixed high-precision reference position units through a receiving antenna, and calculates the current standard coordinates of the standard position terminal based on time difference positioning; A time synchronization unit that provides time synchronization based on one or more of a variety of satellite positioning systems and provides synchronization signals; A test terminal data interface, connected to the standard position terminal, the time synchronization unit and the vehicle-mounted positioning device to be tested; the test terminal data interface is used to obtain the synchronization signal of the time synchronization unit, and obtain the standard coordinates of the standard position terminal at the same time point and the positioning coordinates to be analyzed independently collected by the vehicle-mounted positioning device to be tested based on the synchronization signal; The positioning accuracy analysis module is used to calculate the error of the positioning coordinates to be analyzed by combining the preset relative position and the standard coordinates, and to statistically analyze the dynamic positioning accuracy of the vehicle-mounted positioning device to be tested.

2. The vehicle-mounted positioning equipment dynamic positioning accuracy test system according to claim 1, characterized in that: The fixed high-precision reference position unit includes: a satellite navigation signal receiving antenna, a satellite positioning unit, a high-precision rubidium clock unit, and a time synchronization signal input and output interface; The satellite navigation signal receiving antenna is a multi-band receiving antenna, which is used to support the reception of Beidou satellite positioning signals, GPS positioning signals, Galileo positioning signals and / or GLONASS positioning signals; The satellite positioning unit includes: a Beidou satellite positioning module, a GPS positioning module, a Galileo positioning module and / or a GLONASS positioning module; The satellite positioning unit selects one of the Beidou satellite positioning module, the GPS positioning module, the Galileo positioning module and / or the GLONASS positioning module to perform positioning based on signal strength to obtain the fixed point coordinate data; Alternatively, the satellite positioning unit optimizes the fixed point coordinate data respectively acquired by the Beidou satellite positioning module, the GPS positioning module, the Galileo positioning module and / or the GLONASS positioning module in a weighted average form.

3. The vehicle-mounted positioning equipment dynamic positioning accuracy test system according to claim 1, characterized in that: The time synchronization unit comprises: Beidou satellite navigation signal receiving antenna, used to receive the time signal of Beidou satellite; Beidou timing receiver module, used to demodulate the received time signal, parse out the time information, and provide accurate time mark; High-precision rubidium clock unit, used to perform time calibration after receiving Beidou time signals and maintain a stable internal clock; Time synchronization signal output interface, used to distribute the calibrated time to other devices; Alternatively, the time synchronization unit further configures a plurality of high-precision clock sources to construct redundant backup clocks, and the high-precision clock sources include cesium clocks or GPS clocks.

4. The vehicle-mounted positioning equipment dynamic positioning accuracy test system according to claim 3, characterized in that: The high-precision rubidium clock unit is also provided with a temperature sensor and a frequency adjustment unit; The temperature sensor is used to collect the current ambient temperature in real time; The frequency adjustment unit is used to establish a relationship model between temperature and frequency drift through a linear regression or polynomial fitting method, calculate a frequency drift compensation value according to the relationship model and the current ambient temperature, dynamically adjust the clock frequency, and compensate for the frequency drift caused by temperature changes.

5. The vehicle-mounted positioning equipment dynamic positioning accuracy test system according to claim 1, characterized in that: The system further comprises: A comprehensive display module, used for displaying the working status and detected parameters of the fixed high-precision reference position unit, the standard position terminal, the time synchronization unit, the test terminal data interface and the positioning accuracy analysis module in real time; A parameter configuration module, used to initialize and adjust the operating parameters of the fixed high-precision reference position unit, the standard position terminal, the time synchronization unit, the test terminal data interface and the positioning accuracy analysis module; A test control module, used to control the initiation, stop, process control and abnormal alarm of the positioning accuracy detection of the vehicle-mounted positioning device to be tested; Test data storage module, used for preprocessing, saving, deleting and recording test data; Test data query module, used to query historical test data.

6. The vehicle-mounted positioning equipment dynamic positioning accuracy test system according to claim 1, characterized in that: The test control module is also used to query the data transmission status in the actual application environment according to the operating route of the vehicle-mounted positioning device to be tested, and configure a simulated test environment with similar data transmission status to detect the system; the data transmission status includes data integrity rate, cycle slip ratio, multipath error value and carrier-to-noise ratio.

7. The vehicle-mounted positioning equipment dynamic positioning accuracy test system according to claim 1, characterized in that: The calculation formula for calculating the standard coordinates by the standard position terminal is: Among them, (x1, y1, z1) is the fixed point coordinate data of the first fixed high-precision reference location unit, (x2, y2, z2) is the fixed point coordinate data of the second fixed high-precision reference location unit, and (x3, y3, z3) is the fixed point coordinate data of the third fixed high-precision reference location unit; T1 is the time when the first fixed high-precision reference location unit transmits the model, T2 is the time when the second fixed high-precision reference location unit transmits the model, and T3 is the time when the third fixed high-precision reference location unit transmits the model; T is the time when the data of the first fixed high-precision reference location unit, the second fixed high-precision reference location unit and the third fixed high-precision reference location unit are received; δt is the delay of the signal in the hardware transceiver channel.

8. The vehicle-mounted positioning equipment dynamic positioning accuracy test system according to claim 1, characterized in that: The system is also provided with a standard accuracy correction unit for estimating the standard coordinates based on extended Kalman filtering optimization, including: Setting the initial state of the standard position terminal and its error covariance matrix, wherein the initial state includes position and speed; Use the motion model to predict the state and error covariance at the next moment, and update the error; Calculating a Kalman gain based on the predicted error covariance and current observation data to balance the influence of the predicted data and the observation data; In combination with the observation data, the predicted state is adjusted to obtain the precise position of the standard location terminal; updating the state and the error covariance to reflect the new estimated accuracy; Repeat the above steps.

9. The vehicle-mounted positioning equipment dynamic positioning accuracy test system according to claim 1, characterized in that: The integrated display module is also used to associate the standard coordinates with the railway electronic map and display them visually.

10. The vehicle-mounted positioning equipment dynamic positioning accuracy test system according to claim 1, characterized in that: The positioning accuracy analysis module calculates the Euclidean distance, root mean square error or mean absolute error between the standard coordinates and the positioning coordinates to be analyzed as the positioning accuracy, and displays and visualizes it based on the Grafana platform.

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