A vehicle-to-vehicle channel measurement system and method incorporating a carrier phase differential positioning module

Abstract

A vehicle-to-vehicle channel measurement system and method incorporating a carrier phase differential positioning module is disclosed. The measurement system includes a transmitting vehicle and a receiving vehicle for channel measurement. The transmitting vehicle is equipped with a mobile power station, a power amplifier, a signal generator, a first computer, and a first carrier phase differential positioning module. The receiving vehicle is equipped with a vector network analyzer, a second computer, and a second carrier phase differential positioning module. Instruments are installed in a test vehicle, instrument parameters are configured, and equipment is debugged. Measurements are performed in a driving scenario. Channel characteristic data is obtained by combining relevant parameters of the transmitting and receiving antennas and the data interface of the vector network analyzer. Vehicle driving process data is obtained by combining the positioning information reported by the carrier phase differential positioning system. The above data is aligned according to time, and a scene frame is constructed based on the correspondence between channel characteristics and driving information. This invention can completely reproduce the channel characteristic data and vehicle driving information data in vehicle-to-vehicle channel measurement, as well as their correspondence, solving many inconveniences in applying vehicle-to-vehicle channel measurement results to ray tracing. It offers high measurement accuracy and good results.

Description

Technical Field

[0001] This invention belongs to the technical field of radio wave propagation characteristics and channel characteristics, and particularly relates to a vehicle-to-vehicle channel measurement system and method that combines a carrier phase differential positioning module. Background Technology

[0002] In recent years, with the development of the vehicle industry and the improvement of urban infrastructure and communication facilities, the concept of Vehicle Ad Hoc Networks (VANET) has been proposed and has received widespread attention from industry and academia. Many enterprises and research institutions have begun to realize the demand for vehicle-to-everything (V2X) communication. The V2X communication scenario differs from traditional cellular mobile communication. Cellular communication typically involves communication between a fixed-location base station and a mobile terminal, mostly in line-of-sight scenarios, resulting in relatively simple channel conditions. In contrast, vehicle-to-vehicle communication primarily involves the onboard mobile communication platform, which communicates with other onboard platforms and existing communication network base stations in the traffic environment. Furthermore, vehicles themselves move at high speeds in traffic flow, urban environments, and high-speed road conditions, exhibiting diverse trajectories and making channel conditions relatively complex. To obtain channel parameters such as received power, path loss, and multipath propagation, researchers have studied V2X channels from the perspectives of network characteristics, antenna design, and channel characteristics. Current channel-related research includes findings on network communication and physical layer channels. Vehicle-to-vehicle communication channel models can be divided into two types: statistical models and deterministic models. Among them, the deterministic channel model is mainly based on the ray tracing method.

[0003] Ray tracing is a relatively common channel modeling method. It is a deterministic channel modeling method based on geometric optics, uniform diffraction theory, radio wave propagation mechanism and basic theory. It can perform channel prediction when the geometric model of the wireless communication environment, the electrical parameters of the propagation environment, the parameters of the receiving antenna and the transmitting antenna, and the basic parameters of the radio wave are available.

[0004] The prior art discloses a Sub-6 GHz multi-band wireless channel measurement system and modeling method. Patent application number CN202410416169.9 discloses a Sub-6 GHz multi-band wireless channel measurement system and modeling method. The implementation steps of the method are: (1) build a multi-band wireless channel measurement system; (2) measure the outdoor scene layout and establish a simulated three-dimensional scene model; (3) perform fixed-point measurement on the medium in the outdoor scene; (4) obtain fixed-point simulation results based on the fixed-point measurement results; (5) calibrate the medium parameters of the simulated three-dimensional scene model according to the simulation results; (6) perform continuous channel measurement in the outdoor scene; obtain simulation parameters based on the continuous channel measurement results using the optimal parameter search method; (7) perform global ray simulation tracing on the calibrated simulated three-dimensional scene model and perform parameter matching on the model to obtain a Sub-6 GHz multi-band wireless channel model. This method can accurately reflect the characteristics of the outdoor scene but does not consider the influence of dynamic objects such as vehicles on the channel. It cannot take the geometric shape of the vehicle into the prediction calculation of the vehicle-to-vehicle channel, and it lacks the correspondence between the vehicle's driving information and the spectrum characteristics. The data obtained by this method cannot fully reconstruct the vehicle driving information and channel characteristics in the vehicle-to-vehicle channel. Summary of the Invention

[0005] To overcome the shortcomings of the existing technology, the present invention aims to provide a vehicle-to-vehicle channel measurement system and method incorporating a carrier phase differential positioning module. The system involves installing antennas, signal sources, power amplifiers, vector network analyzers, and other equipment for measuring channel characteristics on a measurement vehicle; installing and debugging the carrier phase differential positioning module on the measurement vehicle; measuring vehicle-to-vehicle communication scenarios to obtain channel characteristic data and vehicle driving information data; and using a data processing program to construct scenario frames based on the channel characteristic data and vehicle driving information data. This aims to solve the problem of measuring vehicle driving information and channel characteristics in vehicle-to-vehicle channel measurement, and to establish the correspondence between driving information and channel characteristics.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A vehicle-to-vehicle channel measurement system incorporating a carrier phase differential positioning module includes: a transmitting vehicle and a receiving vehicle for channel measurement. The transmitting vehicle houses a mobile power station, a power amplifier, a signal generator, a first computer, and a first carrier phase differential positioning module. A transmitting antenna and a first carrier phase differential positioning antenna are mounted on the top of the transmitting vehicle. The mobile power station is connected to the power supply terminals of the power amplifier and the signal generator via power lines. The radio frequency output terminal of the signal generator is connected to the signal input terminal of the power amplifier via a microwave transmission line. The signal output terminal of the power amplifier is connected to the signal input terminal of the transmitting antenna. The first carrier phase differential positioning antenna receives satellite signals and is connected to the data receiving terminal of the first computer in the transmitting vehicle via the first carrier phase differential positioning module.

[0008] The receiving vehicle is equipped with a vector network analyzer, a second computer, and a second carrier phase differential positioning module; a receiving antenna and a second carrier phase differential positioning antenna are installed on the top of the receiving vehicle; the microwave connection end of the vector network analyzer is connected to the receiving antenna through a microwave transmission line, the data output end of the vector network analyzer is connected to the data receiving end of the second computer, and the data receiving end of the second computer is also connected to the output end of the second carrier phase differential positioning antenna through the second carrier phase differential positioning module.

[0009] The first carrier phase differential positioning module is connected to the first computer via a 10 Gigabit Ethernet cable; the vector network analyzer and the second carrier phase differential positioning module are respectively connected to the second computer via 10 Gigabit Ethernet cables.

[0010] A gap is left between the transmitting antenna and the first carrier phase differential positioning antenna to avoid or reduce the line-of-sight path of the transmitting antenna in the horizontal direction being blocked by the positioning antenna.

[0011] A gap is left between the receiving antenna and the second carrier phase differential positioning antenna to avoid or reduce the obstruction of the line-of-sight path of the receiving antenna in the horizontal direction by the positioning antenna.

[0012] The vector network analyzer and carrier phase differential positioning module are connected to the computer via a 10 Gigabit Ethernet cable.

[0013] A vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module, characterized by comprising the following steps:

[0014] Step 1: Configure the channel measurement equipment by installing the receiving antenna and transmitting antenna on the roofs of the transmitting and receiving vehicles, respectively; install the mobile power station, signal generator, and power amplifier in the transmitting vehicle; and install the vector network analyzer in the receiving vehicle. This is used to obtain the required channel characteristic data during the measurement process.

[0015] Step 2: Configure the carrier phase differential positioning module to ensure consistent data return rates for recording vehicle driving information data during the measurement process.

[0016] Step 3: Based on the configurations in Steps 1 and 2, synchronize the carrier phase differential positioning module with the report from the vector network analyzer:

[0017] Step 4: Based on steps 1 to 3, set the required channel measurement equipment parameters and data logging program before measurement:

[0018] Step 5: Based on the settings in Steps 1 to 4, measure the channel characteristic data and vehicle driving information data during the driving process:

[0019] Step 6: Use a data processing program to process the channel characteristic data and vehicle driving information data measured in Step 5 to obtain the scene frame of vehicle-to-vehicle channel measurement.

[0020] The specific method for step 2 is as follows:

[0021] 2.1 The first carrier phase differential positioning module is installed in the transmitting vehicle, and the second carrier phase differential positioning module is installed in the receiving vehicle. A pair of first carrier phase differential positioning antennas are symmetrically installed on the roof of the transmitting vehicle about the direction of travel, maintaining a distance from the transmitting antenna to avoid or reduce the obstruction of the line-of-sight path of the transmitting antenna in the horizontal direction by the positioning antenna; a pair of second carrier phase differential positioning antennas are installed on the roof of the receiving vehicle, maintaining a distance from the receiving antenna to avoid or reduce the obstruction of the line-of-sight path of the receiving antenna in the horizontal direction by the positioning antenna.

[0022] 2.2 Configure the following settings in the operation panels of the first carrier phase differential positioning module and the second carrier phase differential positioning module: ① Set the reference coordinate system to WGS84; ② Align the timestamps of the first carrier phase differential positioning module and the second carrier phase differential positioning module to the same UNIX timestamp; ③ Set the distribution mode of the first carrier phase differential positioning antenna and the second carrier phase differential positioning antenna to "left-right symmetry about the direction of travel". After completing the settings, check the operation panels of the first carrier phase differential positioning module and the second carrier phase differential positioning module. If the inertial navigation system warm-up status of the first carrier phase differential positioning module and the second carrier phase differential positioning module is "warm-up complete", the number of available positioning satellites is greater than 10, and the data reporting rate is greater than 10 times per second, it is considered that the first carrier phase differential positioning module and the second carrier phase differential positioning module are operating normally.

[0023] The specific method of step 3 is as follows: The first computer is installed in the transmitting vehicle, and the second computer is installed in the receiving vehicle; in the transmitting vehicle, the first carrier phase differential positioning module is communicatively connected to the first computer; in the receiving vehicle, the second computer is communicatively connected to the vector network analyzer and the second carrier phase differential positioning module respectively; the interface function of the vector network analyzer is invoked, and the channel parameter reporting program is used to configure the frequency sweep parameters of the vector network analyzer n times per second; the frequency sweep data recording of the vector network analyzer is triggered at the moment when each nth group of data appears in the data reported by the positioning module, and the data is written out in .mat format as channel characteristic data.

[0024] The specific method of step 4 is as follows: drive the transmitting vehicle and the receiving vehicle to the starting point of the measurement route in the measurement scenario, set the signal generator parameters and the power amplifier parameters, and start the carrier phase differential positioning data recording program in the first computer and the second computer, as well as the channel parameter reporting program in the second computer that calls the vector network analyzer interface.

[0025] The specific method for step 5 is as follows:

[0026] 5.1 When the receiving vehicle and the transmitting vehicle are driven to the starting point of the measurement route in the measurement scenario, the second computer starts recording the channel parameter report data, i.e., the channel characteristic data, and then outputs the positioning data recording program data, i.e., the vehicle driving information data, through the command line.

[0027] 5.2 When the two vehicles reach the end position of the measurement scenario, first stop the output of positioning data, and then turn off the data monitoring of the channel parameter reporting program;

[0028] 5.3 Save the channel characteristic data and vehicle driving information data obtained in steps 5.1 and 5.2.

[0029] The specific method of step 6 is as follows: Use any computer to obtain the channel characteristic data and vehicle driving information data obtained from the first and second computers; use a script program written in MATLAB to read the vehicle driving information data and channel characteristic data; index the two sets of data according to UNIX time; and remove invalid data that cannot be matched according to time due to unstable return rates; use a script program written in Python to convert the WGS84 coordinates recorded in the matched data to UTM coordinates, and offset them according to the offset set in the preset construction scene frame; use a script program written in Python to... Dynamic objects (vehicles, etc.) are stitched together with static scenes (ground buildings, etc.) according to the vehicle orientation and posture recorded in the matched data to obtain a simulation scene file in .stl format for each scene frame. A script program written in Python is used to write an antenna parameter file in .csv format for each scene frame, containing the UTM coordinates of the antenna and the basic parameters of the receiving and transmitting antennas, based on the vehicle position in the matched data, the offset of the position recorded by the roof-mounted antenna relative to the positioning system during measurement, and the antenna parameters itself. Finally, scene frames containing vehicle-to-vehicle channel measurement data at each moment are obtained, including the simulation scene, antenna parameters, and channel characteristic data.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] This invention utilizes a channel measurement device, including a receiving antenna, a transmitting antenna, a signal generator, a power amplifier, and a vector network analyzer, to acquire channel characteristic data in vehicle-to-vehicle (V2V) channel scenarios. It also configures a carrier phase differential positioning module and a positioning antenna to acquire vehicle driving information data. Based on these two types of data, a scene frame is established. This scene frame is used to establish a data correlation between the channel characteristic data and vehicle driving information in V2V channel measurements, providing a channel measurement method for ray tracing algorithm research. The data is more organized, enabling faster creation of numerous simulation scenarios within the measurement time period. This provides greater convenience in data processing and simulation calculations. The scene frame contains accurate vehicle attitude and position information, facilitating the selection and use of high-precision and low-precision scene models when combining and constructing simulation scenarios. Therefore, this method offers greater flexibility and versatility in ray tracing simulations. It can be applied to research and production in fields such as wireless channel models, algorithms, and traffic control. Attached Figure Description

[0032] Figure 1 This is a flowchart of a vehicle-to-vehicle channel measurement using a carrier phase differential positioning module, provided in an embodiment of the present invention.

[0033] Figure 2 This is a diagram showing the connection of equipment in the receiving and dispatching vehicles according to an embodiment of the present invention; wherein, Figure 2(a) is a diagram showing the equipment connections in the launch vehicle. Figure 2 (b) is a diagram of the equipment connections in the receiving vehicle.

[0034] Figure 3 This is a schematic diagram of the rooftop antenna installation position provided in an embodiment of the present invention; wherein, Figure 3 (a) Figure 3 (b) Side views of the rooftop antenna mounting positions of the transmitting vehicle and the receiving vehicle, respectively;

[0035] Figure 3 (c) Figure 3 (d) are top views of the rooftop antenna installation positions of the transmitting and receiving vehicles, respectively.

[0036] Figure 4 This is a vehicle driving route map in a latitude and longitude coordinate system provided in an embodiment of the present invention.

[0037] Figure 5 This is a schematic diagram of the simulation environment provided in the embodiments of the present invention.

[0038] Figure 6 This is a dynamic object model diagram (receiving and sending vehicles) provided in an embodiment of the present invention.

[0039] Figure 7 This is a power spectrum obtained by measurement according to an embodiment of the present invention.

[0040] Figure 8 This is a graph showing the absolute speed of a vehicle as measured, provided in an embodiment of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to examples and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0042] This invention primarily utilizes existing channel measurement equipment and a real-time carrier phase positioning module to acquire channel parameter data and vehicle driving information data during the channel measurement process in vehicle-to-vehicle communication scenarios. Scene frames are then constructed using the channel characteristic data and vehicle driving information data, ultimately for ray tracing simulation calculations. For example... Figure 1 A flowchart for measuring vehicle-to-vehicle communication using a carrier phase real-time positioning system.

[0043] A vehicle-to-vehicle channel measurement system incorporating a carrier phase differential positioning module, see [link / reference]. Figure 2The system includes a transmitting vehicle and a receiving vehicle for channel measurement. The transmitting vehicle is equipped with a mobile power station, a power amplifier, a signal generator, a first computer, and a first carrier phase differential positioning module. A transmitting antenna and a first carrier phase differential positioning antenna are mounted on the top of the transmitting vehicle. The mobile power station is connected to the power supply terminals of the power amplifier and the signal generator via power lines. The radio frequency output terminal of the signal generator is connected to the signal input terminal of the power amplifier via a microwave transmission line. The signal output terminal of the power amplifier is connected to the signal input terminal of the transmitting antenna. The first carrier phase differential positioning antenna receives satellite signals and is connected to the data receiving terminal of the first computer on the transmitting vehicle via the first carrier phase differential positioning module.

[0044] The receiving vehicle is equipped with a vector network analyzer, a second computer, and a second carrier phase differential positioning module; a receiving antenna and a second carrier phase differential positioning antenna are installed on the top of the receiving vehicle; the microwave connection end of the vector network analyzer is connected to the receiving antenna through a microwave transmission line, the data output end of the vector network analyzer is connected to the data receiving end of the second computer, and the data receiving end of the second computer is also connected to the output end of the second carrier phase differential positioning antenna through the second carrier phase differential positioning module.

[0045] The first carrier phase differential positioning antenna on the top of the transmitting vehicle and the second wave phase differential positioning antenna on the top of the receiving vehicle are both installed in pairs and are symmetrical about the direction of travel. The equipment connections and antenna assembly are as follows: Figure 2 , Figure 3 As shown.

[0046] A gap is left between the transmitting antenna and the first carrier phase differential positioning antenna to avoid or reduce the obstruction of the line-of-sight path of the transmitting antenna in the horizontal direction by the positioning antenna.

[0047] A gap is left between the receiving antenna and the second carrier phase differential positioning antenna to avoid or reduce the obstruction of the line-of-sight path of the receiving antenna in the horizontal direction by the positioning antenna.

[0048] The first carrier phase differential positioning module is connected to the first computer via a 10 Gigabit Ethernet cable; the vector network analyzer and the second carrier phase differential positioning module are respectively connected to the second computer via 10 Gigabit Ethernet cables.

[0049] A vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module, characterized by comprising the following steps, see below. Figure 1 :

[0050] Step 1: Configure the channel measurement equipment to obtain the required channel characteristic data during the measurement process; install the receiving antenna and transmitting antenna on the roof of the transmitting vehicle and the receiving vehicle, respectively; install the mobile power station, signal generator, and power amplifier in the transmitting vehicle; install the vector network analyzer in the receiving vehicle.

[0051] Step 2: Configure the carrier phase differential positioning module to ensure consistent data return rates for recording vehicle driving information data during the measurement process.

[0052] 2.1 The first carrier phase differential positioning module is installed in the transmitting vehicle, and the second carrier phase differential positioning module is installed in the receiving vehicle. A pair of first carrier phase differential positioning antennas are symmetrically mounted on the roof of the transmitting vehicle about the direction of travel, maintaining a distance from the transmitting antenna to avoid or reduce the obstruction of the horizontal line-of-sight path of the transmitting antenna by the positioning antenna. See [link to relevant documentation]. Figure 3 (a) Figure 3 (b) Mount a pair of second carrier phase differential positioning antennas on the roof of the receiving vehicle, maintaining a distance from the receiving antenna, to avoid or reduce the obstruction of the receiving antenna's line-of-sight path in the horizontal direction by the positioning antennas. See [link to relevant documentation]. Figure 3 (c) Figure 3 (d);

[0053] 2.2 Configure the following settings in the operation panels of the first carrier phase differential positioning module and the second carrier phase differential positioning module: ① Set the reference coordinate system; ② Align the timestamps of the first carrier phase differential positioning module and the second carrier phase differential positioning module to the same UNIX timestamp; ③ Set the distribution mode of the first carrier phase differential positioning antenna and the second carrier phase differential positioning antenna to "left-right symmetry about the direction of travel". After completing the settings, check the operation panels of the first carrier phase differential positioning module and the second carrier phase differential positioning module. If the inertial navigation system warm-up status of the first carrier phase differential positioning module and the second carrier phase differential positioning module is "warm-up complete", the number of available positioning satellites is greater than 10, and the data reporting rate is greater than 10 times per second, it is considered that the first carrier phase differential positioning module and the second carrier phase differential positioning module are operating normally.

[0054] Step 2.2 describes setting the reference coordinate system using the WGS84 coordinate system.

[0055] Step 3: Based on the configurations in Steps 1 and 2, synchronize the carrier phase differential positioning module with the report from the vector network analyzer:

[0056] The first computer is installed in the transmitting vehicle, and the second computer is installed in the receiving vehicle. In the transmitting vehicle, the first carrier phase differential positioning module is connected to the first computer for communication. In the receiving vehicle, the second computer is connected to the vector network analyzer and the second carrier phase differential positioning module for communication. The interface function of the vector network analyzer is invoked, and the channel parameter reporting program is used to configure the frequency sweep parameters of the vector network analyzer n times per second. The frequency sweep data recording of the vector network analyzer is triggered at the time when each nth group of data appears in the data reported by the positioning module. The data is written out in .mat format as channel characteristic data.

[0057] Step 4: Based on steps 1 to 3, set the required channel measurement equipment parameters and data logging program before measurement:

[0058] The transmitting and receiving vehicles are driven to the starting point of the measurement route in the measurement scenario. The parameters of the signal generator and the power amplifier are set. The carrier phase differential positioning data recording program in the first computer and the channel parameter reporting program that calls the vector network analyzer interface in the second computer are started respectively.

[0059] Step 5: Based on the settings in Steps 1 to 4, measure the channel characteristic data and vehicle driving information data during the driving process:

[0060] 5.1 When the receiving vehicle and the transmitting vehicle are driven to the starting point of the measurement route in the measurement scenario, the second computer starts recording the channel parameter report data, i.e., the channel characteristic data, and then outputs the positioning data recording program data, i.e., the vehicle driving information data, through the command line.

[0061] 5.2 When the two vehicles reach the end position of the measurement scenario, first stop the output of positioning data, and then turn off the data monitoring of the channel parameter reporting program;

[0062] 5.3 Save the channel characteristic data and vehicle driving information data obtained in steps 5.1 and 5.2.

[0063] Step 6: Use a data processing program to process the channel characteristic data and vehicle driving information data measured in Step 5 to obtain the scene frame of vehicle-to-vehicle channel measurement:

[0064] Using any computer, channel characteristic data and vehicle driving information data obtained from the first and second computers are acquired. A MATLAB script reads the vehicle driving information data and channel characteristic data, indexes the two sets of data according to UNIX time, and removes invalid data that cannot be matched according to time due to unstable return rates. A Python script converts the WGS84 coordinates recorded in the matched data to UTM coordinates and offsets them according to the preset offset settings of the scene frame. A Python script then stitches dynamic objects (vehicles, etc.) with static scenes (ground buildings, etc.) according to the vehicle orientation recorded in the matched data to obtain a simulation scene file in .stl format for each scene frame. A Python script then writes an antenna parameter file in .csv format for each scene frame based on the vehicle position in the matched data, the offset of the position recorded by the roof-mounted antenna relative to the positioning system during measurement, and the antenna's own parameters. This file contains the UTM coordinates of the antenna and the basic parameters of the receiving and transmitting antennas. Finally, a scene frame containing the simulation scene, antenna parameters, and channel characteristic data at each moment of the vehicle-to-vehicle channel measurement is obtained.

[0065] Simulation verification:

[0066] Convert the static scene in the scene frame into the accelerated file format required for ray tracing calculation: (1) Record the coordinates of all points that participate in the formation of the surface element in the simulation scene model in the point file Points.csv, where the row number is the index value, and x, y, z represent the coordinate values ​​of its position in the UTM coordinate system with the coordinate offset superimposed, such as Figure 6 As shown; (2) Record the information of all face elements in the simulation scene model in the face file Faces.csv, which includes the index values ​​of the three points that make up each face, the normal of the face, and the electrical parameters and material of the face; (3) Record the information of all edges in the simulation scene model in the edge file Corner.csv, which includes the index of the points that make up each edge and the association information of the indexes of the faces on both sides of the edge.

[0067] Configure ray tracing simulation parameters, including the number of rays emitted, reflection order, transmission order, diffraction order, and receiving sphere radius of the ray tracing algorithm, based on the simulation scenario.

[0068] Start the ray tracing simulation script and perform frame-by-frame scene calculations based on the accelerated file obtained from the scene frame conversion and the ray tracing simulation parameters.

[0069] To verify the accuracy of the algorithm, the channel parameters calculated by ray tracing are compared and analyzed with the values ​​in the channel characteristic data.

[0070] Process the messages reported by the carrier phase differential positioning module, and categorize the vehicle's driving information data according to UNIX time, longitude, latitude, and real-time vehicle speed (e.g., ...). Figure 8 The format of the vehicle's orientation azimuth angle should be written as a .csv file.

[0071] The vector network analyzer interface is invoked to write the channel parameter data into a .mat file, organized into three matrices: time, xAxisInfo, and PowerSpectrum. PowerSpectrum contains the power spectrum data obtained from the frequency sweep measurement, with values ​​representing the power intensity received at the receiver. Time represents all UNIX times recorded during the measurement process, totaling t time points. xAxisInfo records the frequency points included in the frequency sweep data, totaling f frequency points, each corresponding to an f×t power data point in PowerSpectrum.

[0072] Move the test vehicle to the designated location in the test scenario in the following order:

[0073] 1) Check whether the measuring equipment is functioning properly and whether the connections between the equipment are normal;

[0074] 2) Configure the data processing program on both computers to ensure that the program performs the specified function;

[0075] 3) Start the RF output of the signal generator and perform channel measurements;

[0076] 4) Process the data to obtain scene frame data.

[0077] Perform ray tracing simulation verification:

[0078] When constructing scene frames, use static scene and dynamic object models, such as Figure 4 , Figure 5 As shown.

[0079] In this embodiment, the driving routes and speeds of the two vehicles in the scene are as follows: Figure 6 , Figure 8 As shown.

[0080] The scene model in the scene frame is converted into an accelerated structure file. Appropriate ray tracing simulation parameters are selected, and ray tracing simulation is used to obtain the predicted received power. 5.9149975 GHz is selected as the simulation prediction frequency. The simulation prediction results are compared with the measurement results. Figure 7 As shown in the figure, RT represents the received power value predicted by the ray tracing simulation, and power represents the measured received power value. The root mean square error between the predicted and measured values ​​is 11.59 dB, which meets the accuracy requirements for applying the ray tracing algorithm to this scenario.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module, characterized in that: Specifically, the following steps are included: Step 1: Configure the channel measurement equipment by installing the receiving antenna and transmitting antenna on the roof of the transmitting vehicle and the receiving vehicle, respectively; install the mobile power station, signal generator, and power amplifier in the transmitting vehicle; and install the vector network analyzer in the receiving vehicle. Used to obtain the required channel characteristic data during the measurement process: Step 2: Configure the carrier phase differential positioning module to ensure consistent data return rates for recording vehicle driving information data during the measurement process. Step 3: Based on the configurations in Steps 1 and 2, synchronize the carrier phase differential positioning module with the report from the vector network analyzer: Step 4: Set the required channel measurement equipment parameters and data logging program before measurement: Step 5: Measure channel characteristic data and vehicle driving information data during the driving process: Step 6: Process the channel characteristic data and vehicle driving information data measured in Step 5 using a data processing program to obtain the scene frame for vehicle-to-vehicle channel measurement, specifically: Vehicle driving information data and channel characteristic data are read and matched. The matched data is then transformed into coordinates and offset according to the preset offset set in the scene frame. The dynamic object is then stitched together with the static scene according to the vehicle orientation recorded in the matched data to obtain the simulation scene file in each scene frame. Based on the vehicle position in the matched data, the offset of the position recorded by the roof-mounted antenna relative to the positioning system during measurement, and the antenna parameters themselves, the antenna parameter file in each scene frame is written, containing the UTM coordinates of the antenna and the basic parameters of the receiving and transmitting antennas. Finally, the scene frames containing the simulation scene, antenna parameters, and channel characteristic data at each moment of the vehicle-to-vehicle channel measurement are obtained.

2. The vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module according to claim 1, characterized in that: The specific method for step 2 is as follows: 2.1 The first carrier phase differential positioning module is installed in the transmitting vehicle, and the second carrier phase differential positioning module is installed in the receiving vehicle. A pair of first carrier phase differential positioning antennas are symmetrically installed on the roof of the transmitting vehicle about the direction of travel, and a distance is maintained between them and the transmitting antenna to avoid or reduce the line-of-sight path of the transmitting antenna in the horizontal direction being blocked by the positioning antenna. A pair of second carrier phase differential positioning antennas are mounted on the roof of the receiving vehicle, maintaining a distance from the receiving antenna, in order to avoid or reduce the obstruction of the receiving antenna's line-of-sight path in the horizontal direction by the positioning antennas. 2.2 Configure the following settings in the operation panels of the first carrier phase differential positioning module and the second carrier phase differential positioning module: ① Set the reference coordinate system to WGS84; ② Align the timestamps of the first carrier phase differential positioning module and the second carrier phase differential positioning module to the same UNIX timestamp; ③ Set the distribution mode of the first carrier phase differential positioning antenna and the second carrier phase differential positioning antenna to "left-right symmetry about the direction of travel". After completing the settings, check the operation panels of the first carrier phase differential positioning module and the second carrier phase differential positioning module. If the inertial navigation system preheating status of the first carrier phase differential positioning module and the second carrier phase differential positioning module is "preheating complete", the number of available positioning satellites is greater than 10, and the data reporting rate is greater than 10 times per second, it is considered that the first carrier phase differential positioning module and the second carrier phase differential positioning module are operating normally.

3. The vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module according to claim 1, characterized in that: The specific method of step 3 is as follows: The first computer is installed in the transmitting vehicle, and the second computer is installed in the receiving vehicle; in the transmitting vehicle, the first carrier phase differential positioning module is communicatively connected to the first computer; in the receiving vehicle, the second computer is communicatively connected to the vector network analyzer and the second carrier phase differential positioning module respectively; the interface function of the vector network analyzer is invoked, and the channel parameter reporting program is used to configure the frequency sweep parameters of the vector network analyzer n times per second; the frequency sweep data recording of the vector network analyzer is triggered at the moment when each nth group of data appears in the data reported by the positioning module, and the data is written out in .mat format as channel characteristic data.

4. The vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module according to claim 1, characterized in that: The specific method of step 4 is as follows: drive the transmitting vehicle and the receiving vehicle to the starting point of the measurement route in the measurement scenario, set the signal generator parameters and the power amplifier parameters, and start the carrier phase differential positioning data recording program in the first computer and the second computer, as well as the channel parameter reporting program in the second computer that calls the vector network analyzer interface.

5. The vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module according to claim 1, characterized in that: The specific method for step 5 is as follows: 5.1 When the receiving vehicle and the transmitting vehicle are driven to the starting point of the measurement route in the measurement scenario, the second computer starts recording the channel parameter report data, i.e., the channel characteristic data, and then outputs the positioning data recording program data, i.e., the vehicle driving information data, through the command line. 5.2 When the two vehicles reach the end position of the measurement scenario, first stop the output of positioning data, and then turn off the data monitoring of the channel parameter reporting program; 5.3 Save the channel characteristic data and vehicle driving information data obtained in steps 5.1 and 5.

2.

6. The vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module according to claim 1, characterized in that: The specific method of step 6 is as follows: Use any computer to obtain the channel characteristic data and vehicle driving information data obtained by the first computer and the second computer; use a script program written in MATLAB to read the vehicle driving information data and channel characteristic data; use UNIX time as an index to match the two sets of data; and remove invalid data that cannot be matched according to time due to unstable return rate; use a script program written in Python to convert the WGS84 coordinates recorded in the matched data to UTM coordinates, and offset them according to the offset set in the preset construction scene frame. A script written in Python is used to stitch dynamic objects together with the static scene according to the vehicle orientation and posture recorded in the matched data, resulting in a simulation scene file in .stl format for each scene frame. Another script written in Python is used to write an antenna parameter file in .csv format for each scene frame, containing the antenna's UTM coordinates and basic parameters of the receiving and transmitting antennas, based on the vehicle position in the matched data, the offset of the roof-mounted antenna relative to the position recorded by the positioning system during measurement, and the antenna's own parameters. Finally, scene frames containing the simulation scene, antenna parameters, and channel characteristic data for each moment of the vehicle-to-vehicle channel measurement are obtained.

7. A system based on the vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module as described in any one of claims 1 to 6, comprising: The transmitting and receiving vehicles used for channel measurement are characterized by: The launch vehicle is equipped with a mobile power station, a power amplifier, a signal generator, a first computer, and a first carrier phase differential positioning module. A transmitting antenna and a first carrier phase differential positioning antenna are mounted on the top of the launch vehicle. The mobile power station is connected to the power amplifier and the signal generator via power cables. The RF output of the signal generator is connected to the signal input of the power amplifier via a microwave transmission line. The signal output of the power amplifier is connected to the signal input of the transmitting antenna. The first carrier phase differential positioning antenna receives satellite signals and is connected to the data receiving end of the first computer via the first carrier phase differential positioning module. The receiving vehicle is equipped with a vector network analyzer, a second computer, and a second carrier phase differential positioning module; a receiving antenna and a second carrier phase differential positioning antenna are installed on the top of the receiving vehicle; the microwave connection end of the vector network analyzer is connected to the receiving antenna through a microwave transmission line, the data output end of the vector network analyzer is connected to the data receiving end of the second computer, and the data receiving end of the second computer is also connected to the output end of the second carrier phase differential positioning antenna through the second carrier phase differential positioning module.

8. The system for vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module according to claim 7, characterized in that: The first carrier phase differential positioning antenna on the top of the transmitting vehicle and the second wave phase differential positioning antenna on the top of the receiving vehicle are both arranged in pairs and are symmetrical about the direction of travel.

9. The system for vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module according to claim 7, characterized in that: A gap is left between the transmitting antenna and the first carrier phase differential positioning antenna to avoid or reduce the line-of-sight path of the transmitting antenna in the horizontal direction being blocked by the positioning antenna. A gap is left between the receiving antenna and the second carrier phase differential positioning antenna to avoid or reduce the obstruction of the line-of-sight path of the receiving antenna in the horizontal direction by the positioning antenna.

10. The system for vehicle-to-vehicle channel measurement method combining a carrier phase differential positioning module according to claim 7, characterized in that: The first carrier phase differential positioning module is connected to the first computer via a 10 Gigabit Ethernet cable; the vector network analyzer and the second carrier phase differential positioning module are respectively connected to the second computer via 10 Gigabit Ethernet cables.

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