Vehicle-mounted RTK differential positioning device test method and system, and storage medium

Abstract

The present application relates to the technical field of device testing, solves the problem that there is no RTK differential positioning device testing scheme capable of truly and controllably reproducing multipath propagation effect in a vehicle application scenario in the prior art, and provides a vehicle-mounted RTK differential positioning device testing method, system and storage medium, a virtual physical environment is constructed according to a testing plan; signal simulation is performed according to vehicle motion parameters and environment parameters, to obtain direct signals and synthetic signals; differential correction is performed according to the direct signals, to obtain correction data; the synthetic signals and the correction data are input into a to-be-tested vehicle-mounted RTK differential positioning device for positioning calculation, to obtain calculated vehicle motion parameters; and a testing result of the to-be-tested vehicle-mounted RTK differential positioning device is obtained according to the calculated vehicle motion parameters and the vehicle motion parameters. The embodiment of the present application improves testing accuracy by constructing a virtual physical environment, simulating an actual driving scenario, and taking vehicle motion parameters and environment parameters into account.

Description

Technical Field

[0001] This invention relates to the field of equipment testing technology, and in particular to a testing method, system and storage medium for vehicle-mounted RTK differential positioning equipment. Background Technology

[0002] With the development of autonomous driving and intelligent connected vehicles, the accuracy and reliability of satellite high-precision positioning equipment are crucial. RTK differential positioning technology can achieve centimeter-level positioning accuracy by correcting user terminal errors through a reference station. However, in typical vehicle application scenarios such as urban canyons, tunnels, or densely built-up areas, the propagation path of satellite signals changes complexly due to building obstruction and multipath effects such as signal reflection and diffraction. This easily introduces non-line-of-sight signal interference, severely reducing the accuracy and stability of RTK positioning, and even leading to positioning drift or failure. Therefore, the ability to realistically and controllably reproduce the aforementioned multipath propagation environment during the testing phase becomes the key to evaluating the performance of vehicle-mounted RTK differential positioning equipment.

[0003] Existing Chinese patent CN109343089A discloses a performance testing method for general positioning devices. This method generates satellite signals for a virtual location using a GNSS simulator and differential correction data using a reference station simulator. An error jammer is used to simulate satellite orbit errors, clock errors, and network transmission interference. Finally, the virtual location is compared with the device's calculated results to obtain accuracy, repeatability, and dynamic performance indicators. However, this method primarily focuses on the impact of error source injection and system-level interference on positioning accuracy. It lacks spatial environment modeling based on specific vehicle application scenarios and does not involve simulation of multipath signal propagation mechanisms in complex environments such as urban canyons, tunnels, or densely populated high-rise areas. Therefore, it is difficult to reflect the impact of multipath effects on positioning performance in actual road environments.

[0004] Existing Chinese patent CN113703004A discloses a reliability testing method for vehicle-mounted millimeter-wave radar. This method utilizes a radar signal simulator to generate echo signals and, combined with factors such as temperature, humidity, vibration, and absorption environment, detects the radar's operating status under different external environments. It evaluates radar operational reliability by analyzing positioning motion information and matching environmental parameters. However, this scheme primarily simulates physical environmental conditions (temperature, humidity, vibration) and does not address the modeling and control of signal propagation paths and multipath effects. Therefore, it cannot meet the testing requirements of vehicle-mounted high-precision positioning equipment in complex multipath scenarios.

[0005] Therefore, how to construct virtual physical scenarios based on simulation scenario software that can characterize typical vehicle application environments such as urban canyons, tunnels, or densely built-up areas, and how to controllably simulate multipath propagation effects in the virtual physical scenarios, thereby realizing the real-world testing of the performance of vehicle-mounted RTK differential positioning devices in complex multipath environments, is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a testing method, system and storage medium for vehicle-mounted RTK differential positioning devices, in order to solve the problem that the prior art lacks a testing scheme for RTK differential positioning devices that can realistically and controllably reproduce multipath propagation effects in vehicle application scenarios.

[0007] In a first aspect, embodiments of the present invention provide a testing method for a vehicle-mounted RTK differential positioning device, the method comprising: A virtual physical environment for vehicle-mounted application scenarios is constructed according to the test plan. The virtual physical environment includes vehicle motion parameters and environmental parameters used to characterize multipath propagation conditions. Based on the vehicle motion parameters and environmental parameters, signal simulation is performed to obtain direct signals and synthetic signals; Differential correction is performed based on the direct signal to obtain correction data; The synthesized signal and the correction data are input into the vehicle-mounted RTK differential positioning device under test for positioning calculation to obtain the calculated vehicle motion parameters. Based on the calculated vehicle motion parameters and the vehicle motion parameters, the test results of the vehicle-mounted RTK differential positioning device under test are obtained.

[0008] Preferably, the step of simulating signals based on the vehicle motion parameters and environmental parameters to obtain direct signals and synthetic signals includes: Simulate multiple target satellites and the corresponding signals for each target satellite using a GNSS simulator; For any target satellite, the direct signal is obtained by simulating the vehicle motion parameters using a GNSS simulator; The vehicle motion parameters and environmental parameters are simulated using the GNSS simulator to obtain multipath signals. The direct signal and the multipath signal are combined to obtain the composite signal corresponding to each target satellite.

[0009] Preferably, for any target satellite, a direct signal is obtained by simulating the vehicle motion parameters using a GNSS simulator, including: The vehicle motion parameters are obtained, including vehicle position, vehicle speed, and vehicle attitude. For any target satellite, the propagation delay is obtained based on the geometric relationship between the GNSS simulator, the vehicle's position, and the ephemeris coordinates of the target satellite. The Doppler shift is obtained based on the relative change between the vehicle speed and the target satellite speed; The received power parameters are obtained based on the vehicle attitude and the incident direction of the target satellite; The direct signal is obtained by synthesizing the propagation delay, the Doppler frequency shift, and the received power parameters.

[0010] Preferably, the step of simulating multipath signals based on the vehicle motion parameters and environmental parameters using the GNSS simulator to obtain multipath signals includes: Based on the GNSS simulator and the vehicle motion parameters, determine multiple propagation paths of the target satellite signal under the environmental parameters, as well as the propagation delay, Doppler shift, and received power parameters of each propagation path; Based on the propagation delay, Doppler shift, and received power parameters of each propagation path, the component signal corresponding to each propagation path is obtained; By superimposing all component signals, a multipath signal is obtained.

[0011] Preferably, the step of performing differential correction based on the direct signal to obtain correction data includes: For any target satellite, the direct signal of the target satellite is sent to the differential base station, and the first pseudorange observation value and the first carrier phase observation value of the target satellite are calculated based on the differential base station. The calculated positions corresponding to the first pseudorange observation value and the first carrier phase observation value are compared with the preset known coordinates of the base station to obtain the pseudorange residual and phase residual of the target satellite. Correction data for the target satellite is generated based on the pseudorange residual and phase residual.

[0012] Preferably, the step of inputting the synthesized signal and the correction data into the on-board RTK differential positioning device under test for positioning calculation to obtain the calculated vehicle motion parameters includes: For any target satellite, the synthetic signal of the target satellite is demodulated by the vehicle-mounted RTK differential positioning device under test to obtain the second pseudorange observation value and the second carrier phase observation value of the target satellite; Based on the correction data, differential correction is analyzed between the second pseudorange observation value and the second carrier phase observation value to obtain the pseudorange correction value corresponding to the second pseudorange observation value and the phase correction value corresponding to the second carrier phase observation value. The second pseudorange observation is corrected based on the pseudorange correction to obtain the third pseudorange observation; The second carrier phase observation value is corrected according to the phase correction number to obtain the third phase observation value; Based on the third pseudorange and third phase observations of each target satellite, multi-satellite joint positioning calculations are performed to obtain the vehicle motion parameters.

[0013] Preferably, obtaining the test results of the on-board RTK differential positioning device under test based on the calculated vehicle motion parameters and the vehicle motion parameters includes: The calculated vehicle motion parameters are compared one-to-one with the vehicle motion parameters to obtain the differences between the two in terms of position coordinates, velocity vector and time synchronization. The performance indicators are obtained based on the differences between the two in terms of position coordinates, velocity vectors, and time synchronization. The performance indicators are compared with preset thresholds to obtain the performance level evaluation of the vehicle-mounted RTK differential positioning device under test in the virtual physical environment. Based on the performance level evaluation of the vehicle-mounted RTK differential positioning device under test in different virtual physical environments, a comprehensive performance curve is constructed.

[0014] Preferably, the step of comparing the calculated vehicle motion parameters with the actual vehicle motion parameters one-to-one to obtain the differences between the two in terms of position coordinates, velocity vector, and time synchronization includes: Based on the timestamp sequence in the vehicle motion parameters, multiple reference test epochs are determined; Based on the output timestamp in the calculated vehicle motion parameters, the calculated vehicle motion parameters are time-matched with each of the reference test epochs to obtain the time matching result corresponding to each reference test epoch. When the time deviation between any reference test epoch and the corresponding output timestamp is not greater than the preset synchronization threshold, the calculated vehicle motion parameters corresponding to the output timestamp are determined as the synchronous calculated vehicle motion parameters corresponding to the reference test epoch. When any reference test epoch does not match an output timestamp with a time deviation not greater than a preset synchronization threshold, interpolation is performed based on the calculated vehicle motion parameters located before and after the reference test epoch to obtain the synchronous calculated vehicle motion parameters corresponding to the reference test epoch. The calculated position coordinates in the synchronously calculated vehicle motion parameters are compared with the reference position coordinates in the vehicle motion parameters to obtain the position coordinate difference. The calculated velocity vector in the synchronously calculated vehicle motion parameters is compared with the reference velocity vector in the vehicle motion parameters to obtain the velocity vector difference. The time synchronization difference is obtained based on the time deviation between the output timestamp and the reference test epoch.

[0015] Secondly, embodiments of the present invention provide a vehicle-mounted RTK differential positioning device testing system, the system comprising: A scene simulation engine used to build virtual physical environments; GNSS simulator, used for signal simulation; Differential base stations are used for differential correction; An automated testing platform is used to generate test plans and output test results; The automated testing platform includes: The test tool management module is used to configure and maintain the GNSS simulator and programmable power supply hardware tools. The device under test (DUT) management module is used to manage the access and status of vehicle-mounted RTK differential positioning devices. The test case management module is used to store the multipath scenario library; The test plan management module is used to create test plans. The test execution monitoring module is used to monitor the test execution status in real time. The test result management module is used to analyze the result data and output performance indicators, including positioning deviation and convergence time. The test report management module is used to generate test reports, which include positioning accuracy analysis and multipath impact assessment. The data storage management module is used to store test process data and test results.

[0016] Thirdly, embodiments of the present invention provide a storage medium storing computer program instructions, which, when executed by a processor, implement the method of the first aspect described above.

[0017] In summary, the beneficial effects of the present invention are as follows: The vehicle-mounted RTK differential positioning device testing method, system, and storage medium provided in this invention first construct a virtual physical environment for vehicle-mounted application scenarios according to the test plan. Vehicle motion parameters and environmental parameters used to characterize multipath propagation conditions are uniformly incorporated into the test input. This allows the vehicle motion state, spatial occlusion relationship, and signal reflection conditions in complex road environments such as urban canyons, tunnels, and densely populated high-rise areas to be parameterized and described at the test front end, thereby providing a scenario basis for the reproduction of multipath propagation effects. Based on this, signal simulation is performed according to vehicle motion parameters and environmental parameters to obtain direct signal and synthetic signal respectively. Furthermore, the multipath propagation effect caused by environmental factors is superimposed on the synthetic signal so that the input signal received by the device under test can closely approximate the satellite signal propagation state in a real vehicle scenario. Subsequently, differential correction is performed using the direct signal to obtain correction data. The synthesized signal and correction data are then input together into the vehicle-mounted RTK differential positioning device under test for positioning calculation. On the one hand, the real interference of multipath effect on the terminal reception and calculation process is preserved. On the other hand, differential correction maintains the controllability and comparability of test conditions and avoids other common errors from excessively masking the test results. Finally, by comparing the calculated vehicle motion parameters with the preset vehicle motion parameters, the test results are obtained, thereby enabling a quantitative evaluation of the positioning performance of the device under test in complex vehicle scenarios.

[0018] By combining virtual scene construction with multipath signal simulation, the real reproduction and controllable testing of multipath propagation effects in vehicle application scenarios were achieved. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, and these are all within the protection scope of the present invention.

[0020] Figure 1 This is a flowchart illustrating the testing method for an on-board RTK differential positioning device according to an embodiment of the present invention. Figure 1 .

[0021] Figure 2 This is a flowchart illustrating the testing method for a vehicle-mounted RTK differential positioning device according to an embodiment of the present invention. Figure 2 .

[0022] Figure 3 This is a schematic diagram of the structure of the vehicle-mounted RTK differential positioning equipment testing system according to an embodiment of the present invention. Detailed Implementation

[0023] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0025] It should be noted that all actions involving the acquisition of signals, information, or data in this invention are carried out in compliance with the relevant data protection laws and regulations of the locality and with authorization from the owner of the relevant device.

[0026] Example 1 This application embodiment is applied to a vehicle-mounted RTK differential positioning equipment testing system. The system includes: a scene simulation engine for constructing a virtual physical environment; a GNSS simulator for signal simulation; a differential base station for differential correction; and an automated testing platform for generating test plans and outputting test results.

[0027] Further, please see Figure 1 This invention provides a testing method for a vehicle-mounted RTK differential positioning device, the method comprising: S101. Construct a virtual physical environment for vehicle application scenarios according to the test plan. The virtual physical environment includes vehicle motion parameters and environmental parameters used to characterize multipath propagation conditions. Specifically, the virtual physical environment refers to a scene where real roads, buildings, and the atmosphere are digitally modeled under a unified coordinate and time scale; vehicle motion parameters refer to the sequence of vehicle position, speed, and attitude that changes over time; environmental parameters refer to scene geometry (streets, bridges, tunnels, etc.), material reflection / scattering characteristics, obstructions, and atmospheric conditions such as the ionosphere / troposphere. Environmental parameters can be classified to obtain test results for each set of environmental parameters. Classifications can include urban environmental parameters, rural environmental parameters, tunnel environmental parameters, open area environmental parameters, etc. The purpose of this step is to externalize what to measure, under what environment to measure, and which constellations / frequency points to use in the test plan into a repeatable, controllable, and traceable unified input, thereby providing a consistent benchmark for subsequent signal simulation, differential analysis, and evaluation. During implementation, the constellation and frequency, sampling rate and duration are determined according to the test plan. The time reference and coordinate system are set, and the vehicle position-velocity-attitude timing sequence is generated based on the trajectory template or road network. The scene library and material library are called to arrange the three-dimensional geometry and assign dielectric constant, roughness and reflection coefficient to the surface / volume elements. At the same time, the ionosphere / troposphere model is loaded according to the meteorological settings and the ephemeris time synchronization and antenna reference point calibration are completed. If necessary, the visible satellites and the obstruction area and the candidate reflective surface set are pre-calculated and the vehicle motion parameter set + environmental parameter set is output. The beneficial effects of this are that the scene, motion and error source are all parameterized and versioned, the experiment can be reproduced, the variables can be separated, the boundary conditions can be controlled, and it is convenient for large-scale regression and comparative experiments.

[0028] S102. Perform signal simulation based on the vehicle motion parameters and environmental parameters to obtain direct signals and synthetic signals; Specifically, the direct signal is the component of the shortest path from the satellite to the receiver that has not been reflected / scattered / diffused; the multipath signal is several non-direct path components generated by the environment; the composite signal is the radio frequency / intermediate frequency baseband stream obtained by superimposing the direct signal and multipath signal of the same satellite and then merging them with the multi-satellite signal. The purpose of this step is to reproduce the propagation characteristics in a real road environment indoors, so that the vehicle-mounted RTK differential positioning device under test can expose the performance boundaries caused by multipath and obstruction under controllable conditions. In practice, the time delay τ and the Doppler fd of the relative velocity can be obtained by calculating the geometric distance based on the vehicle's position and ephemeris. The direct component amplitude is then calibrated by combining the antenna pattern and free space loss. Subsequently, based on the environmental geometry and materials, one-hop or multi-hop reflection / scattering / diffraction paths are searched using methods such as mirror method / ray tracing / Monte Carlo diffuse reflection. The time delay, phase, attenuation, and frequency shift of each path are obtained according to the path length, incident and reflection angles, Fresnel coefficients, or BRDF model, and component signals are generated. After being aligned in time and phase, the signals are superimposed one by one to obtain the composite signal of that satellite. This composite signal is then merged with the composite signals of other satellites. If necessary, receiver noise, oscillator phase noise, quantization noise, and bandwidth limitations are injected to form the final composite signal. The beneficial effect of this is that the signal contains both geometric and motion effects as well as path group effects caused by the environment, resulting in high fidelity, adjustable difficulty, and test results that are highly correlated with road scenes.

[0029] S103. Perform differential correction based on the direct signal to obtain correction data; Specifically, differential correction refers to the process of estimating common errors (satellite clock errors, orbital errors, atmospheric delays, etc.) and broadcasting correction information using a reference station with known coordinates. The purpose of this step is to minimize common errors even in the presence of multipath interference, shorten convergence time, and improve solution accuracy, providing a cleaner observation base for evaluating terminal algorithm capabilities. In implementation, the differential base station receives the direct signal from S202 at its known coordinates, demodulates the multi-satellite pseudorange and carrier phase observations, calculates the theoretical geometric distance and phase based on the ephemeris / clock error true values ​​and APC calibration, obtains the satellite-by-satellite pseudorange residuals and phase residuals, and combines this with electrical... Common error decomposition and smoothing filtering are performed on the exospheric model (such as Klobuchar / NeQuick), the tropospheric model (such as Saastamoinen), and the orbit correction. This generates satellite-by-satellite pseudorange corrections and phase corrections, which are then packaged according to RTCM3.x messages (such as 1004 / 1077, 1006, 1033, etc.), with added time stamps and integrity flags, and periodically output via serial port / Ethernet. The beneficial effect of this step is that it removes environmentally irrelevant systematic errors from terminal observations, significantly improving the stability and repeatability of centimeter-level calculations, and facilitating horizontal comparisons between different terminals or different algorithms.

[0030] S104. Input the synthesized signal and the correction data into the vehicle-mounted RTK differential positioning device under test for positioning calculation to obtain the calculated vehicle motion parameters; Specifically, the tested vehicle-mounted RTK differential positioning equipment refers to a terminal with multi-satellite and multi-frequency reception, differential calculation, and ambiguity fixing capabilities; observation correction refers to applying corrections to the original pseudorange / phase observations to obtain observations that are closer to the true geometry; joint calculation includes weighted least squares / extended Kalman filtering and integer ambiguity fixing (such as LAMBDA); its purpose is to enable the terminal to output PVT (position / velocity / time) and quality indicators that are as close as possible to the true trajectory under the combined action of synthetic signals containing multipath and differential correction, thereby truly exposing the advantages and disadvantages of the tracking and calculation link; in practice, the terminal completes the acquisition / tracking of the synthetic signal and outputs multi-satellite and multi-frequency pseudorange, carrier phase, and multi-dimensional ambiguity. The Puller algorithm analyzes RTCM corrections and performs satellite and epoch matching to correct and interpolate observations. Then, under unified coordinates and time scales, it performs observation modeling, random model weighting, RAIM / integrity monitoring, and anti-multipath weighting suppression. It performs filtering estimation and integer ambiguity search-verification-fixing (or maintains floating-point solutions) to obtain quality quantifications such as PVT, covariance matrix, DOP, fixation rate, and TTFF / TTFA. The intermediate states and results are then transmitted back to the test platform. Its beneficial effect is that it measures not only position but also quantifiable indicators reflecting robustness and dynamism (such as fixation time and loss / reacquisition time), thus providing a panoramic view of the terminal's real performance in complex scenarios.

[0031] S105. Based on the calculated vehicle motion parameters and the vehicle motion parameters, the test results of the vehicle-mounted RTK differential positioning device under test are obtained.

[0032] Specifically, test results can include RMSE, horizontal / vertical 95% error (CEP95 / LE95 / VE95), fixation rate, convergence time, availability, long-term drift, and error distribution. The purpose of this step is to convert the terminal output into objective, comparable, and traceable conclusions, providing a basis for R&D optimization and mass production release. In practice, the trajectory generated by the terminal PVT and S201 can be registered and interpolated according to the epoch timescale, and a uniform conversion and antenna phase center correction can be completed between geographic coordinates. The position or velocity error and statistical distribution of each epoch can be calculated, and segmented evaluation and robustness analysis can be performed according to scene segments (such as urban canyons, tunnels, or elevated roads). Outlier identification and integrity measurement are performed, and conclusions are given according to standard thresholds or grade rules (such as A, B, or C levels). A report containing error curves, box plots, fixation rate heatmaps, and event timelines is automatically generated and archived. The beneficial effect of this step is to condense complex time-series data into a standardized, multi-dimensional indicator system, realize horizontal comparability and vertical regression between different devices or scenes, and significantly improve the persuasiveness and engineering availability of test conclusions.

[0033] Please refer to Figure 2 In some embodiments, S102, signal simulation is performed based on the vehicle motion parameters and environmental parameters to obtain direct signals and synthetic signals, including: S201. Simulate multiple target satellites and the corresponding signals for each target satellite using a GNSS simulator; Specifically, the target satellites refer to the set of satellites selected in the test plan that are visible and participate in the calculation. By loading ephemeris or calendar and messages according to the test plan in the GNSS simulator, setting the simulation start and end times and sampling rate, selecting constellation and PRN number, setting elevation angle interception, carrier parameters and navigation message rate, and configuring transmit power spectral density, number of channels, frequency point combination, reference clock model and output format when necessary, the configuration and timing baseline of multi-target satellites and multi-frequency signals are obtained. Its beneficial effect is that the dimensions of satellites and signals participating in the simulation are determined at one time, with high coverage and traceable parameters, providing a stable entry point for the generation of direct signals and multipath signals on a satellite-by-satellite basis and reducing subsequent uncertainties.

[0034] S202. For any target satellite, simulate the direct signal based on the vehicle motion parameters using a GNSS simulator to obtain the direct signal; Specifically, the direct signal refers to the shortest path component from the satellite to the receiver without reflection, scattering, or diffraction. The purpose of this step is to establish a reference component that is geometrically and motionally consistent for each target satellite, so that subsequent multipath signals only serve as additional disturbances and do not affect the reference phase and code synchronization. In implementation, based on the conventional geometric propagation model, the geometric distance and incident direction under ECEF / ENU are calculated according to the vehicle position and satellite ephemeris. Propagation delay τ and code phase positioning are performed. Doppler is obtained by projecting the relative velocity between the satellite and the vehicle in the propagation direction. The amplitude is calibrated according to free space path loss and combined with the receiving antenna pattern. At the same time, the PRN code and navigation message at the corresponding frequency point are superimposed, and time-scale alignment and frequency synthesis are completed to obtain the direct signal of the satellite. Its beneficial effect is to provide a reference for phase and code, ensuring that the receiver still has the correct acquisition anchor point after the subsequent multipath signals are superimposed, thereby improving the physical consistency of the simulation.

[0035] S203. Multipath signal simulation is performed on the vehicle motion parameters and environmental parameters using the GNSS simulator to obtain multipath signals; Specifically, the purpose of this step is to reconstruct the main degradation mechanisms of GNSS propagation in complex scenarios such as urban canyons and under overpasses, and to quantify their impact on code and carrier delay, amplitude, and frequency shift. This can be achieved using the mirror method and ray tracing method: based on the vehicle attitude and satellite incident direction, search for one-hop and necessary two-hop mirror surfaces and obstructions; perform intersection detection, path length, and incident / exit angle calculations for each candidate path; obtain amplitude / phase and polarization changes according to Fresnel reflection, BRDF, or Lambertian scattering models; and provide component Doppler from the velocity components of the relative motion along the path direction. For rough surfaces, the signal can be trimmed according to a power threshold or upper limit of the number of paths to obtain a set of component signals with τ, attenuation, phase, and frequency shift attributes. Its beneficial effect is that the multipath intensity and distribution are controllable and reproducible.

[0036] S204. The direct signal and the multipath signal are combined to obtain the composite signal corresponding to each target satellite.

[0037] Specifically, the synthesis process refers to the linear superposition of the direct signal and multipath signal according to the time, phase, and frequency relationships under a uniform sampling rate or bandwidth. Component alignment refers to the synchronization of the code phase and carrier phase based on τ and the initial phase. The purpose of this step is to generate a real and outputtable single-satellite synthetic signal for each target satellite, which retains the LOS reference and includes NLOS perturbation, providing a physically consistent input for subsequent processing. In implementation, based on the direct signal obtained in S302 and the multipath signal obtained in S303, interpolation resampling, time delay shifting, phase rotation, and amplitude scaling are performed. Pulse shaping is completed according to the set bandwidth, and then all signals are superimposed in the same local oscillator and sampling clock domain to obtain the synthetic signal corresponding to the target satellite. Its beneficial effect is that the output synthetic signal of a single target satellite simultaneously contains key features such as code delay distortion and carrier phase oscillation, which facilitates subsequent multi-satellite superposition and receiver channel-level evaluation, and ensures comparability and traceability between different scenarios and rounds.

[0038] In some implementations, S202, for any target satellite, the vehicle motion parameters are simulated using a GNSS simulator to obtain a direct signal, including: The vehicle motion parameters are obtained, including vehicle position, vehicle speed, and vehicle attitude. For any target satellite, the propagation delay is obtained based on the geometric relationship between the GNSS simulator, the vehicle's position, and the ephemeris coordinates of the target satellite. Specifically, propagation delay refers to the time difference between a satellite signal being transmitted from the satellite and received by the receiver, and is usually calculated from the path length and the speed of light. The purpose of this step is to calculate the propagation delay of the signal based on the geometric relationship (i.e., position difference) between the vehicle and the satellite, which is used for subsequent pseudorange calculations and signal synchronization. Based on the vehicle's position and the target satellite's ephemeris coordinates, the three-dimensional spatial distance between the vehicle and the satellite can be calculated first. Then, based on the known speed of light, the propagation delay can be obtained. By calculating the propagation delay, the relative distance between the vehicle and the satellite can be accurately determined, serving as the basis for pseudorange measurement.

[0039] The Doppler shift is obtained based on the relative change between the vehicle speed and the target satellite speed; Specifically, vehicle speed refers to the vehicle's velocity in space, usually represented by a three-dimensional velocity vector; target satellite speed refers to the target satellite's velocity in its orbit, also represented by a three-dimensional velocity vector; Doppler shift refers to the offset between the received signal frequency and the transmitted signal frequency, usually caused by the relative motion between the receiver and the signal source. The purpose of this step is to calculate the Doppler shift caused by the relative motion between the vehicle and the satellite, which affects the signal frequency. The relative velocity vector can be obtained from the difference between the vehicle's and the target satellite's velocity vectors. The relative velocity components are calculated based on the projection of the relative velocity vector onto the signal propagation direction. The Doppler shift is then obtained from the relative velocity components, the original frequency of the satellite signal, and the speed of light. By calculating the Doppler shift, the signal frequency can be adjusted, eliminating the frequency error caused by the relative motion between the vehicle and the satellite, thereby ensuring accurate signal reception and the accuracy of subsequent positioning calculations.

[0040] The received power parameters are obtained based on the vehicle attitude and the incident direction of the target satellite; Specifically, vehicle attitude refers to the vehicle's pitch, roll, and yaw angles relative to the ground or other reference frame, affecting the directivity of the receiver antenna; the incident direction of the target satellite refers to the directivity of the signal propagation path from the satellite to the receiver; and received power refers to the signal strength received by the receiver from the satellite. The purpose of this step is to calculate the signal power on the receiver antenna, considering the vehicle's attitude and the directivity of the signal propagation path. Based on the vehicle's attitude parameters, the main lobe direction of the receiver antenna can be calculated, yielding the antenna gain function. Based on the relative position of the target satellite's incident direction and the receiving antenna, the incident angle of the signal in the antenna direction can be calculated. Based on the incident angle and the antenna directivity model, the received power parameters are obtained. By calculating the received power parameters, the signal gain can be adjusted according to the vehicle's attitude and the signal propagation path, improving signal quality.

[0041] The direct signal is obtained by synthesizing the propagation delay, the Doppler frequency shift, and the received power parameters.

[0042] Specifically, this step involves shifting the signal in time based on the propagation delay. This step ensures that the signal reception time matches its propagation delay. The signal frequency is adjusted based on the Doppler shift to compensate for frequency variations caused by relative velocity. The signal amplitude is adjusted based on the received power to ensure the received signal strength meets expectations. By accurately calculating the propagation delay, Doppler shift, and received power parameters, the synthesized direct signal can realistically simulate the satellite signal propagation process, providing reliable input for subsequent positioning calculations.

[0043] In some embodiments, the step of simulating multipath signals based on the vehicle motion parameters and environmental parameters using the GNSS simulator to obtain multipath signals includes: Based on the GNSS simulator and the vehicle motion parameters, determine multiple propagation paths of the target satellite signal under the environmental parameters, as well as the propagation delay, Doppler shift, and received power parameters of each propagation path; Specifically, this step obtains multiple propagation paths that a single target satellite's signal may have under a single environmental parameter, and then generates propagation delay, Doppler shift, and received power parameters for each propagation path, providing realistic parameter support for the generation of multipath signals.

[0044] Based on the propagation delay, Doppler shift, and received power parameters of each propagation path, the component signal corresponding to each propagation path is obtained; Specifically, component signals refer to satellite signals propagating through individual propagation paths. Each path generates a separate signal, which are independent but superimposed at the receiver. The purpose of this step is to apply these influencing factors—propagation delay, Doppler shift, and received power parameters—to the signal from each propagation path to generate corresponding component signals. These component signals represent different propagation paths and will be used for subsequent signal synthesis.

[0045] In some implementations, S103, differential correction is performed based on the direct signal to obtain correction data, including: For any target satellite, the direct signal of the target satellite is sent to the differential base station, and the first pseudorange observation value and the first carrier phase observation value of the target satellite are calculated based on the differential base station. Specifically, pseudorange observations are relative distances obtained by calculating the propagation delay of the satellite signal from the satellite to the base station; for distinction, this is referred to as the first pseudorange observation. Carrier phase observations are more accurate distance information obtained by measuring the phase offset of the received signal; for distinction, this is referred to as the first carrier phase observation. The differential base station receives the direct signal transmitted by the target satellite and demodulates the signal based on the satellite ephemeris and the known base station location to obtain the pseudorange and carrier phase observations of the target satellite. The purpose of this process is to obtain accurate pseudorange and phase observation data as the basis for subsequent differential positioning calculations, ensuring that the base station can provide accurate positioning references for the receiver.

[0046] The calculated positions corresponding to the first pseudorange observation value and the first carrier phase observation value are compared with the preset known coordinates of the base station to obtain the pseudorange residual and phase residual of the target satellite. Specifically, pseudorange residuals reflect errors in signal propagation, typically caused by factors such as satellite clock errors and atmospheric delays; phase residuals, on the other hand, are caused by errors in phase measurements (such as periodic errors or other systematic errors). Differential base stations compare the calculated position from pseudorange and phase observations with the base station's known coordinates to obtain the pseudorange and phase residuals of the target satellite. Through the calculation of these residuals, differential base stations can quantify and identify the sources of error in the signal, providing data support for the subsequent generation of accurate correction data.

[0047] Correction data for the target satellite is generated based on the pseudorange residual and phase residual.

[0048] Specifically, the differential base station generates correction data for the target satellite based on the pseudorange and phase residuals calculated in the previous step. The calculation results of the pseudorange and phase residuals are used to derive the corresponding pseudorange and phase corrections, which correct errors in the satellite signal, making it closer to the true satellite signal. Based on this, the differential base station generates correction data containing pseudorange and phase corrections, as well as other possible error correction information (such as ionospheric and atmospheric delay), and packages it for transmission to the device under test. The core purpose of this step is to eliminate signal errors through correction data and improve the positioning accuracy of the device.

[0049] In some embodiments, S104, the synthesized signal and the correction data are input into the on-board RTK differential positioning device under test for positioning calculation to obtain the calculated vehicle motion parameters, including: For any target satellite, the synthetic signal of the target satellite is demodulated by the vehicle-mounted RTK differential positioning device under test to obtain the second pseudorange observation value and the second carrier phase observation value of the target satellite; Specifically, demodulation processing refers to processing the synthesized signal using a demodulator to extract useful information from the satellite signal. The purpose of this step is to demodulate the received synthesized signal from the target satellite using the vehicle-mounted RTK differential positioning device under test, and obtain the second pseudorange observation value and the second carrier phase observation value output by the vehicle-mounted RTK differential positioning device under test.

[0050] Based on the correction data, differential correction is analyzed between the second pseudorange observation value and the second carrier phase observation value to obtain the pseudorange correction value corresponding to the second pseudorange observation value and the phase correction value corresponding to the second carrier phase observation value. Specifically, the pseudorange correction is used to correct the differential data of the pseudorange observations, and is calculated and output by the differential base station. The phase correction is used to correct the differential data of the carrier phase observations, and is also calculated and output by the differential base station. The purpose of this step is to analyze the differential corrections of the second pseudorange observation and the second carrier phase observation using the vehicle-mounted RTK differential positioning device under test and the correction data to obtain the pseudorange correction and phase correction.

[0051] The second pseudorange observation is corrected based on the pseudorange correction to obtain the third pseudorange observation; Specifically, the purpose of this step is to correct the second pseudorange observation based on the pseudorange correction, thereby obtaining a more accurate third pseudorange observation. Errors in the satellite signal can be eliminated by subtracting the pseudorange correction.

[0052] The second carrier phase observation value is corrected according to the phase correction number to obtain the third phase observation value; Specifically, the purpose of this step is to obtain a more accurate third phase observation by applying phase corrections to correct the carrier phase observation.

[0053] Based on the third pseudorange and third phase observations of each target satellite, multi-satellite joint positioning calculations are performed to obtain the vehicle motion parameters.

[0054] Specifically, the multi-satellite joint positioning solution uses pseudorange and phase observations from multiple satellites to perform joint calculations, obtaining the final vehicle position, velocity, and clock deviation. The calculated vehicle motion parameters are the dynamic information such as three-dimensional position, velocity, and time output by the vehicle-mounted RTK differential positioning device under test. The purpose of this step is to calculate the vehicle's three-dimensional position, velocity, and other motion parameters through multi-satellite joint solution, combining the third pseudorange and third phase observations, eliminating other interference factors. This ensures that the positioning results output by the vehicle-mounted RTK differential positioning device under test are only related to the virtual physical environment, thereby improving the testing effect of the vehicle-mounted RTK differential positioning device.

[0055] In some implementations, S105, based on the calculated vehicle motion parameters and the vehicle motion parameters, the test results of the on-board RTK differential positioning device under test are obtained, including: The calculated vehicle motion parameters are compared one-to-one with the vehicle motion parameters to obtain the differences between the two in terms of position coordinates, velocity vector and time synchronization. Specifically, the purpose of this step is to compare the motion parameters calculated by the under-test vehicle-mounted RTK differential positioning device with the motion parameters of a reference vehicle to obtain the difference between the two. This comparison quantifies the errors in positioning accuracy, velocity accuracy, and time synchronization, helping to evaluate the device's performance. Based on the known motion parameters of the reference vehicle and the calculation results of the under-test device, the position coordinates, velocity vectors, and time synchronization of the two are compared one-to-one. This can be implemented by: calculating the difference between position coordinates to obtain the position accuracy error; calculating the difference between velocity vectors to obtain the velocity error; and calculating the time synchronization error to obtain the time deviation. Finally, the differences in position, velocity, and time synchronization are obtained, and these differences will be used to evaluate positioning accuracy and system stability.

[0056] In some implementations, the step of comparing the calculated vehicle motion parameters with the actual vehicle motion parameters one-to-one to obtain the differences between the two in terms of position coordinates, velocity vector, and time synchronization includes: Based on the timestamp sequence in the vehicle motion parameters, multiple reference test epochs are determined; Based on the output timestamp in the calculated vehicle motion parameters, the calculated vehicle motion parameters are time-matched with each of the reference test epochs to obtain the time matching result corresponding to each reference test epoch. Specifically, the timestamp sequence in the vehicle motion parameters serves as the time reference when the scene simulation engine generates the reference vehicle motion trajectory. For example, a reference test epoch is formed every 0.1s, 0.2s, or 1s. Each reference test epoch corresponds to a set of reference vehicle position, reference vehicle speed, and reference vehicle attitude. First, multiple consecutive or selected reference test epochs at preset sampling intervals are extracted from the timestamp sequence as the reference time for subsequent error comparison. Then, the calculated vehicle motion parameters and their output timestamps output by the on-board RTK differential positioning device under test are read. Each set of calculated vehicle motion parameters is matched with the reference test epochs according to the output timestamps. For example, if the reference test epoch is 10.0s, and the device output timestamps are 9.98s and 10.03s, the calculation result with smaller time deviation or meeting the threshold requirement can be selected as the matching result of the reference test epoch according to the preset synchronization threshold.

[0057] When the time deviation between any reference test epoch and the corresponding output timestamp is not greater than the preset synchronization threshold, the calculated vehicle motion parameters corresponding to the output timestamp are determined as the synchronous calculated vehicle motion parameters corresponding to the reference test epoch. When any reference test epoch does not match an output timestamp with a time deviation not greater than a preset synchronization threshold, interpolation is performed based on the calculated vehicle motion parameters located before and after the reference test epoch to obtain the synchronous calculated vehicle motion parameters corresponding to the reference test epoch. Specifically, after matching the reference test epoch with the output timestamp of the calculated vehicle motion parameters, the data output by the on-board RTK differential positioning device under test is time-synchronized. The preset synchronization threshold can be pre-set according to the sampling period of the test system, the output frequency of the GNSS simulator, the data reporting frequency of the device under test, and the test accuracy requirements. This threshold is used to determine whether the calculated vehicle motion parameters corresponding to a certain output timestamp can directly represent the solution result under the corresponding reference test epoch. When the time deviation between any reference test epoch and its matched output timestamp is not greater than the preset synchronization threshold, it indicates that the set of calculated vehicle motion parameters is sufficiently close to the reference test epoch in time, and the calculated results such as position and velocity corresponding to the output timestamp can be directly determined as the synchronous calculated vehicle motion parameters under the reference test epoch. When there is no output timestamp that meets the preset synchronization threshold near a certain reference test epoch, the calculated vehicle motion parameters located before and after the reference test epoch are selected, and the position coordinates, velocity vectors, and other data are interpolated according to the time interval to obtain the synchronous calculated vehicle motion parameters corresponding to the reference test epoch.

[0058] The calculated position coordinates in the synchronously calculated vehicle motion parameters are compared with the reference position coordinates in the vehicle motion parameters to obtain the position coordinate difference. The calculated velocity vector in the synchronously calculated vehicle motion parameters is compared with the reference velocity vector in the vehicle motion parameters to obtain the velocity vector difference. The time synchronization difference is obtained based on the time deviation between the output timestamp and the reference test epoch.

[0059] Specifically, after the vehicle motion parameters have been synchronized to the reference test epoch, the output results of the on-board RTK differential positioning device under test are quantified for error. First, the calculated position coordinates in the synchronously calculated vehicle motion parameters are extracted under the same reference test epoch, and the reference position coordinates in the vehicle motion parameters are also extracted. The two can be compared under the same coordinate system, such as the Northeast-Sky coordinate system, the Geocentric-Earth-Fixed coordinate system, or the Latitude-Longitude-Height coordinate system, before conversion and calculation. This yields the position coordinate difference, which can be further used to calculate the horizontal position error, vertical position error, or three-dimensional position error. Then, the calculated velocity vector and the reference velocity vector under the same reference test epoch are extracted, and the differences between the two in the longitudinal, lateral, vertical, or velocity magnitude are compared to obtain the velocity vector difference, which reflects the accuracy of the device under test in solving the vehicle motion velocity. At the same time, based on the time deviation between the output timestamp of the device under test and the reference test epoch, the time synchronization difference is obtained, which characterizes the degree of synchronization of the device's solution results with respect to the simulation reference time axis.

[0060] The performance indicators are obtained based on the differences between the two in terms of position coordinates, velocity vectors, and time synchronization. Specifically, performance metrics refer to standards for measuring the performance of vehicle-mounted RTK differential positioning equipment, including positioning accuracy, velocity accuracy, and time synchronization accuracy. Implementation methods may include: calculating position accuracy metrics, such as RMSE (Root Mean Square Error) or CEP95 (95% probability of circular error), based on position differences; calculating velocity error metrics, such as maximum velocity error or velocity consistency error, based on velocity differences; and calculating time deviations, such as clock synchronization error, based on time synchronization differences. By comprehensively calculating these differences, a set of performance metrics is obtained, reflecting the overall performance of the device under test in terms of position, velocity, and time synchronization. This step, by quantifying error values, provides clear performance metrics, enabling precise evaluation of the equipment's performance in various aspects.

[0061] In some implementations, obtaining performance metrics based on the differences between the two in position coordinates, velocity vectors, and time synchronization includes: Based on the position coordinate difference, calculate the horizontal position error and vertical position error at each reference test epoch. Based on the velocity vector difference, calculate the velocity error at each reference test epoch; Based on the time synchronization difference, calculate the time synchronization error at each reference test epoch; Specifically, after obtaining the position coordinate difference, velocity vector difference, and time synchronization difference, the original differences are further converted into single-epoch error data that can be used for statistical evaluation. The position coordinate difference is decomposed according to a unified coordinate system. For example, in the Northeast-Northeast coordinate system, the eastward and northward differences are combined to form the horizontal position error, and the celestial difference is used as the vertical position error. If latitude, longitude, and altitude coordinates are used, the latitude and longitude differences can be converted into planar distances to obtain the horizontal position error, and the vertical position error can be obtained based on the altitude difference. The velocity vector difference can be calculated as the velocity modulus error according to the test requirements, or the longitudinal velocity error, lateral velocity error, or vertical velocity error can be calculated separately to reflect the deviation of the device under test in calculating the vehicle's speed. The time synchronization difference can be directly taken as the absolute value of the time deviation between the output timestamp and the reference test epoch, used as the time synchronization error under that reference test epoch, to evaluate the consistency between the device's output data and the simulation reference time axis.

[0062] A horizontal position error sample set is formed based on the horizontal position error under multiple reference test epochs; a vertical position error sample set is formed based on the vertical position error under multiple reference test epochs; a velocity error sample set is formed based on the velocity error under multiple reference test epochs; and a time synchronization error sample set is formed based on the time synchronization error under multiple reference test epochs. Statistical processing is performed on the horizontal position error sample set, the vertical position error sample set, the velocity error sample set, and the time synchronization error sample set to obtain horizontal positioning accuracy, vertical positioning accuracy, velocity measurement accuracy, and time synchronization error indicators. The performance index is obtained based on at least one of the horizontal positioning accuracy, the vertical positioning accuracy, the speed measurement accuracy, and the time synchronization error index.

[0063] Specifically, after obtaining the single-shot error at each reference test epoch, the dispersed error data is organized into evaluation data that can represent the overall performance of a test process. According to the test time sequence, test scenario segment, or test item number, the horizontal position errors at multiple reference test epochs are summarized into a horizontal position error sample set. The vertical position error, velocity error, and time synchronization error are summarized into vertical position error sample sets, velocity error sample sets, and time synchronization error sample sets, respectively. The error values ​​in each sample set all originate from continuous test results within the same test item or the same virtual physical environment.

[0064] Subsequently, statistical processing was performed on each sample set. The statistical method can be selected according to the test requirements, such as root mean square error, average error, maximum error, standard deviation, or 95th percentile value. The horizontal position error sample set is used to obtain the horizontal positioning accuracy, the vertical position error sample set is used to obtain the vertical positioning accuracy, the speed error sample set is used to obtain the speed measurement accuracy, and the time synchronization error sample set is used to obtain the time synchronization error index.

[0065] Finally, appropriate indicators are selected to form performance indicators based on the evaluation objects of the current test project. For example, the static positioning accuracy test and dynamic positioning accuracy test mainly select horizontal positioning accuracy and vertical positioning accuracy, and the speed measurement accuracy test mainly selects speed measurement accuracy. If it is necessary to evaluate the consistency between the equipment output data and the reference time axis, the time synchronization error indicator is further introduced.

[0066] The performance indicators are compared with preset thresholds to obtain the performance level evaluation of the vehicle-mounted RTK differential positioning device under test in the virtual physical environment. Specifically, preset thresholds refer to performance standards set according to industry standards or testing requirements, typically including the tolerance ranges for position accuracy, velocity accuracy, and time synchronization accuracy. The purpose of this step is to compare the calculated performance indicators with the preset threshold standards, thereby generating a performance level evaluation for the vehicle-mounted RTK differential positioning device under test. This evaluation helps determine whether the device meets design and application requirements. The implementation process compares the device's performance indicators with the preset threshold values ​​to determine whether each indicator is within the standard range. Based on the error values ​​of position accuracy, velocity accuracy, and time synchronization accuracy, it is determined whether the device meets the preset standards: if the error is within the threshold range, it is rated as excellent (e.g., Grade A); if the error is slightly larger but still meets the basic requirements, it is rated as acceptable (e.g., Grade B); if the error exceeds the threshold range, it is rated as unacceptable (e.g., Grade C). Finally, a performance level evaluation is generated, and the overall performance of the device in the virtual physical environment is reported.

[0067] In some implementations, comparing the performance indicators with preset thresholds to obtain a performance level evaluation of the vehicle-mounted RTK differential positioning device under test in the virtual physical environment includes: Based on the scene type and test item type corresponding to the virtual physical environment, a corresponding preset threshold is determined. The scene type includes at least one of open sky scene and urban canyon scene. The test item type includes at least one of static positioning accuracy test, dynamic positioning accuracy test and speed measurement accuracy test. When the test item type is static positioning accuracy test or dynamic positioning accuracy test, the horizontal positioning accuracy and the vertical positioning accuracy are compared with the corresponding preset positioning accuracy thresholds to obtain the positioning accuracy comparison results. When the test item type is speed measurement accuracy test, the speed measurement accuracy is compared with the corresponding preset speed measurement accuracy threshold to obtain the speed measurement accuracy comparison result. The performance level evaluation is determined based on the positioning accuracy comparison result or the speed measurement accuracy comparison result.

[0068] Specifically, after obtaining the horizontal positioning accuracy, vertical positioning accuracy, and speed measurement accuracy, a graded evaluation of the vehicle-mounted RTK differential positioning device under test is conducted based on the specific test scenario and test items. First, the scene type is determined according to the current virtual physical environment. For example, an open sky scene typically has less occlusion and weak multipath propagation, making it suitable as an evaluation scenario for the device's basic positioning performance; an urban canyon scene, with building occlusion, reflection, and non-line-of-sight propagation, is more suitable for evaluating the device's stability under complex multipath conditions. Simultaneously, the test plan determines whether a static positioning accuracy test, dynamic positioning accuracy test, or speed measurement accuracy test is being performed. Different test items focus on different indicators, therefore, corresponding preset thresholds need to be called. For static and dynamic positioning accuracy tests, the horizontal and vertical positioning accuracy are mainly compared with preset positioning accuracy thresholds, for example, determining whether the horizontal and vertical errors both meet the requirements of the corresponding scenario, thus obtaining the positioning accuracy comparison result. For speed measurement accuracy tests, the speed measurement accuracy is mainly compared with a preset speed measurement accuracy threshold, obtaining the speed measurement accuracy comparison result. Finally, the performance level is determined based on the comparison results corresponding to the current test items. For example, if all indicators meet the higher thresholds, it can be judged as a higher level; if some indicators only meet the basic thresholds, it can be judged as an intermediate level; and if it exceeds the allowable thresholds, it can be judged as a lower level. By setting thresholds and evaluating them separately according to scenario type and test item type, this method can avoid the distortion of results caused by using the same evaluation standard for open sky scenarios and urban canyon scenarios, or for positioning tests and speed tests. This makes the performance level evaluation more in line with the actual testing requirements of different vehicle application scenarios.

[0069] Based on the performance level evaluation of the vehicle-mounted RTK differential positioning device under test in different virtual physical environments, a comprehensive performance curve is constructed.

[0070] Specifically, the comprehensive performance curve refers to a performance curve plotted based on performance level evaluations under different virtual physical environments, which can display the overall performance changes of the device in different scenarios. The purpose of this step is to construct a comprehensive performance curve based on performance level evaluations under multiple virtual physical environments, visually displaying the device's performance fluctuations in various environments, facilitating the selection and deployment of the device in practical applications. The implementation process involves statistically analyzing the performance performance in different environments based on the performance level evaluation for each virtual physical environment, recording the performance indicators and level evaluations for each environment. These performance levels are then summarized according to environmental conditions (such as multipath effects, signal obstruction, dynamic environments, etc.) to construct the comprehensive performance curve, which presents the device's performance in different environments in a graphical format. The comprehensive performance curve can use indicators such as accuracy and reliability as the vertical axis and the type of environmental parameter (such as urban, rural, tunnel, open area) as the horizontal axis, showing the trend of device performance changes with the environment. By constructing the comprehensive performance curve, the overall performance of the device in different environments can be visually displayed, helping users or R&D teams understand the device's adaptability and make more appropriate application choices and optimization directions.

[0071] In some implementations, constructing a comprehensive performance curve based on the performance level evaluation of the vehicle-mounted RTK differential positioning device under test in different virtual physical environments includes: Acquire the performance indicators and performance level evaluations of the vehicle-mounted RTK differential positioning device under test in multiple virtual physical environments; According to the test item types corresponding to the multiple virtual physical environments, the performance indicators are divided into static positioning accuracy performance indicators, dynamic positioning accuracy performance indicators, and speed measurement accuracy performance indicators. Based on the static positioning accuracy performance index, the dynamic positioning accuracy performance index and the speed measurement accuracy performance index, corresponding performance points are generated respectively, and the corresponding performance level evaluation is used as the level identifier of the performance point. The performance points are sorted according to the scenario type or test item execution order of the virtual physical environment. The comprehensive performance curve is constructed based on the sorted performance points.

[0072] Specifically, after completing multiple virtual physical environments and multiple test projects, the scattered test results are compiled into a comprehensive evaluation result that can reflect the overall performance change trend of the device. First, the performance indicators and performance level evaluations of the vehicle-mounted RTK differential positioning device under test are obtained in different virtual physical environments, such as static positioning accuracy in open sky scenarios, dynamic positioning accuracy in urban canyon scenarios, and speed measurement accuracy in different scenarios. These performance indicators were then categorized according to the type of test item. Indicators used to evaluate the ability to calculate position in a static state were classified as static positioning accuracy performance indicators, indicators used to evaluate the ability to calculate position during vehicle movement were classified as dynamic positioning accuracy performance indicators, and indicators used to evaluate the ability to calculate speed were classified as speed measurement accuracy performance indicators.

[0073] Next, corresponding performance points are generated based on each type of performance indicator. These performance points can be characterized by scene type, test item type, specific performance value, and performance level evaluation. The performance level evaluation serves as the grade identifier for the performance point, ensuring that subsequent curves not only reflect numerical changes but also the corresponding pass / fail level or performance grade. Then, multiple performance points are sorted according to the scene type of the virtual physical environment or the execution order of the test items in the test plan. For example, performance points in an open sky scene are sorted first, followed by those in an urban canyon scene, or they can be sorted in the order of static positioning, dynamic positioning, and speed measurement.

[0074] A comprehensive performance curve is constructed based on multiple ranked performance points to demonstrate the performance changes of the device under test under different scenarios and test items. This process transforms isolated evaluation results from a single test into continuous and comparable performance trends.

[0075] Example 2 Please see Figure 3 This invention provides a vehicle-mounted RTK differential positioning device testing system, the system comprising: A scene simulation engine used to build virtual physical environments; GNSS simulator, used for signal simulation; Differential base stations are used for differential correction; An automated testing platform used to generate test plans and output test results.

[0076] The automated testing platform also includes: The test tool management module is used to configure and maintain the GNSS simulator and programmable power supply hardware tools. The device under test (DUT) management module is used to manage the access and status of vehicle-mounted RTK differential positioning devices. The test case management module is used to store the multipath scenario library; The test plan management module is used to create test plans. The test execution monitoring module is used to monitor the test execution status in real time. The test result management module is used to analyze the result data and output performance indicators, including positioning deviation and convergence time. The test report management module is used to generate test reports, which include positioning accuracy analysis and multipath impact assessment. The data storage management module is used to store test process data and test results.

[0077] Specifically, the scene simulation engine is used to construct a virtual physical environment and output vehicle motion parameters (position, speed, attitude) and environmental parameters (building geometry, material properties, etc.); these parameters are then transmitted to the GNSS simulator to generate corresponding satellite signals.

[0078] The GNSS simulator receives vehicle motion parameters and environmental parameters output by the scene simulation engine. Based on these parameters, it generates direct and multipath signals for each target satellite and synthesizes them into a composite signal. The composite signal is then input to the vehicle-mounted RTK differential positioning device under test to simulate satellite signal reception in complex environments. Simultaneously, it communicates with the automated testing platform to receive test case configuration and signal generation control commands.

[0079] Differential base stations can be RTK differential simulation base stations, used to receive direct signals output by GNSS simulators, calculate pseudorange residuals and phase residuals of each satellite, generate correction data, and send it to the vehicle-mounted RTK differential positioning equipment under test via data link for differential correction.

[0080] The vehicle-mounted RTK differential positioning device under test is used to receive synthetic signals generated by a GNSS simulator and correction data output by an RTK differential simulation base station; perform differential positioning calculations to obtain calculated vehicle motion parameters (position, speed, time, etc.); and feed the calculation results back to an automated testing platform for subsequent result comparison and performance evaluation.

[0081] The automated testing platform includes functional modules such as test tool management, device under test (DUT) management, test case management, test plan management, test execution monitoring, test result management, test report management, and data storage management. It is used to uniformly schedule GNSS simulators, RTK differential base stations, and vehicle-mounted RTK differential positioning devices under test to execute test tasks. After collecting the calculation results of the DUT, it compares and analyzes them with the real vehicle motion parameters generated by the scene simulation engine to form test results and automatically output test reports.

[0082] The programmable power supply is used to provide a stable and controllable power supply to the vehicle-mounted RTK differential positioning equipment under test, ensuring the continuity and consistency of the testing process.

[0083] Example 3 Furthermore, in conjunction with the methods in the above embodiments, the present invention can be implemented using a computer-readable storage medium. This computer-readable storage medium stores computer program instructions; when executed by a processor, these computer program instructions implement any of the methods in the above embodiments.

[0084] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are 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. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0085] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0086] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0087] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0088] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0089] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0090] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A testing method for a vehicle-mounted RTK differential positioning device, characterized in that, The method includes: A virtual physical environment for vehicle-mounted application scenarios is constructed according to the test plan. The virtual physical environment includes vehicle motion parameters and environmental parameters used to characterize multipath propagation conditions. Based on the vehicle motion parameters and environmental parameters, signal simulation is performed to obtain direct signals and synthetic signals; Differential correction is performed based on the direct signal to obtain correction data; The synthesized signal and the correction data are input into the vehicle-mounted RTK differential positioning device under test for positioning calculation to obtain the calculated vehicle motion parameters. Based on the calculated vehicle motion parameters and the vehicle motion parameters, the test results of the vehicle-mounted RTK differential positioning device under test are obtained.

2. The method according to claim 1, characterized in that, The step of simulating signals based on the vehicle motion parameters and environmental parameters to obtain direct signals and synthetic signals includes: Simulate multiple target satellites and the corresponding signals for each target satellite using a GNSS simulator; For any target satellite, the direct signal is obtained by simulating the vehicle motion parameters using a GNSS simulator; The vehicle motion parameters and environmental parameters are simulated using the GNSS simulator to obtain multipath signals. The direct signal and the multipath signal are combined to obtain the composite signal corresponding to each target satellite.

3. The method according to claim 2, characterized in that, For any target satellite, the direct signal is obtained by simulating the vehicle motion parameters using a GNSS simulator, including: The vehicle motion parameters are obtained, including vehicle position, vehicle speed, and vehicle attitude. For any target satellite, the propagation delay is obtained based on the geometric relationship between the GNSS simulator, the vehicle's position, and the ephemeris coordinates of the target satellite. The Doppler shift is obtained based on the relative change between the vehicle speed and the target satellite speed; The received power parameters are obtained based on the vehicle attitude and the incident direction of the target satellite; The direct signal is obtained by synthesizing the propagation delay, the Doppler frequency shift, and the received power parameters.

4. The method according to claim 2, characterized in that, The step of simulating multipath signals based on the vehicle motion parameters and environmental parameters using the GNSS simulator to obtain multipath signals includes: Based on the GNSS simulator and the vehicle motion parameters, determine multiple propagation paths of the target satellite signal under the environmental parameters, as well as the propagation delay, Doppler shift, and received power parameters of each propagation path; Based on the propagation delay, Doppler shift, and received power parameters of each propagation path, the component signal corresponding to each propagation path is obtained; By superimposing all component signals, a multipath signal is obtained.

5. The method according to any one of claims 1-4, characterized in that, The step of performing differential correction based on the direct signal to obtain correction data includes: For any target satellite, the direct signal of the target satellite is sent to the differential base station, and the first pseudorange observation value and the first carrier phase observation value of the target satellite are calculated based on the differential base station. The calculated positions corresponding to the first pseudorange observation value and the first carrier phase observation value are compared with the preset known coordinates of the base station to obtain the pseudorange residual and phase residual of the target satellite. Correction data for the target satellite is generated based on the pseudorange residual and phase residual.

6. The method according to any one of claims 1-4, characterized in that, The step of inputting the synthesized signal and the correction data into the on-board RTK differential positioning device under test for positioning calculation to obtain the calculated vehicle motion parameters includes: For any target satellite, the synthetic signal of the target satellite is demodulated by the vehicle-mounted RTK differential positioning device under test to obtain the second pseudorange observation value and the second carrier phase observation value of the target satellite; Based on the correction data, differential correction is analyzed between the second pseudorange observation value and the second carrier phase observation value to obtain the pseudorange correction value corresponding to the second pseudorange observation value and the phase correction value corresponding to the second carrier phase observation value. The second pseudorange observation is corrected based on the pseudorange correction to obtain the third pseudorange observation; The second carrier phase observation value is corrected according to the phase correction number to obtain the third phase observation value; Based on the third pseudorange and third phase observations of each target satellite, multi-satellite joint positioning calculations are performed to obtain the vehicle motion parameters.

7. The method according to any one of claims 1-4, characterized in that, The step of obtaining the test results of the vehicle-mounted RTK differential positioning device under test based on the calculated vehicle motion parameters and the vehicle motion parameters includes: The calculated vehicle motion parameters are compared one-to-one with the vehicle motion parameters to obtain the differences between the two in terms of position coordinates, velocity vector and time synchronization. The performance indicators are obtained based on the differences between the two in terms of position coordinates, velocity vectors, and time synchronization. The performance indicators are compared with preset thresholds to obtain the performance level evaluation of the vehicle-mounted RTK differential positioning device under test in the virtual physical environment. Based on the performance level evaluation of the vehicle-mounted RTK differential positioning device under test in different virtual physical environments, a comprehensive performance curve is constructed.

8. The method according to claim 7, characterized in that, The step of comparing the calculated vehicle motion parameters with the actual vehicle motion parameters one-to-one to obtain the differences between the two in terms of position coordinates, velocity vector, and time synchronization includes: Based on the timestamp sequence in the vehicle motion parameters, multiple reference test epochs are determined; Based on the output timestamp in the calculated vehicle motion parameters, the calculated vehicle motion parameters are time-matched with each of the reference test epochs to obtain the time matching result corresponding to each reference test epoch. When the time deviation between any reference test epoch and the corresponding output timestamp is not greater than the preset synchronization threshold, the calculated vehicle motion parameters corresponding to the output timestamp are determined as the synchronous calculated vehicle motion parameters corresponding to the reference test epoch. When any reference test epoch does not match an output timestamp with a time deviation not greater than a preset synchronization threshold, interpolation is performed based on the calculated vehicle motion parameters located before and after the reference test epoch to obtain the synchronous calculated vehicle motion parameters corresponding to the reference test epoch. The calculated position coordinates in the synchronously calculated vehicle motion parameters are compared with the reference position coordinates in the vehicle motion parameters to obtain the position coordinate difference. The calculated velocity vector in the synchronously calculated vehicle motion parameters is compared with the reference velocity vector in the vehicle motion parameters to obtain the velocity vector difference. The time synchronization difference is obtained based on the time deviation between the output timestamp and the reference test epoch.

9. A vehicle-mounted RTK differential positioning device testing system, characterized in that, The system includes: A scene simulation engine used to build virtual physical environments; GNSS simulator, used for signal simulation; Differential base stations are used for differential correction; An automated testing platform is used to generate test plans and output test results; The automated testing platform includes: The test tool management module is used to configure and maintain the GNSS simulator and programmable power supply hardware tools. The device under test (DUT) management module is used to manage the access and status of vehicle-mounted RTK differential positioning devices. The test case management module is used to store the multipath scenario library; The test plan management module is used to create test plans. The test execution monitoring module is used to monitor the test execution status in real time. The test result management module is used to analyze the result data and output performance indicators, including positioning deviation and convergence time. The test report management module is used to generate test reports, which include positioning accuracy analysis and multipath impact assessment. The data storage management module is used to store test process data and test results.

10. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by a processor, the method as described in any one of claims 1-8 is implemented.

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