Vehicle-to-vehicle channel measurement system and method combined with carrier phase difference positioning module

Abstract

The invention relates to a vehicle-to-vehicle channel measurement system and method combined with a carrier phase difference positioning module, the measurement system comprises a transmitting vehicle and a receiving vehicle which are used for channel measurement, a mobile power station, a power amplifier, a signal generator, a first computer and a first carrier phase difference positioning module are arranged in the transmitting vehicle; a vector network analyzer, a second computer and a second carrier phase difference positioning module are mounted in the receiving vehicle; instruments are installed in the vehicle for testing, instrument parameters are configured, equipment is debugged, and measurement is carried out in a driving scene; the method comprises the following steps: acquiring channel characteristic data by combining relevant parameters of a receiving and transmitting antenna and a data interface of a vector network analyzer, acquiring vehicle driving process data by combining positioning information reported by a carrier phase difference positioning system, aligning the data according to time, and constructing a scene frame according to a corresponding relationship between the channel characteristic and the driving information; according to the invention, the channel characteristic data and the vehicle driving information data in the vehicle-to-vehicle channel measurement and the corresponding relation between the channel characteristic data and the vehicle driving information data can be completely reproduced, the inconvenience of the measurement result of the vehicle-to-vehicle channel when being applied to ray tracking is solved, the measurement accuracy is high, and the effect is good.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio wave propagation characteristics and channel characteristics, and in particular, relates to a vehicle-to-vehicle channel measurement system and method combined with a carrier phase differential positioning module. Background Art

[0002] In recent years, with the development of the vehicle industry and the completion of urban infrastructure and communication facilities, the concept of vehicle self-organizing network (VANET) has been proposed and has received widespread attention from the industry and academia. Many companies and research and development institutions have begun to realize the demand for vehicle networking. The communication scenario of vehicle networking is different from traditional cellular mobile communication. Cellular communication scenarios usually establish communication between base stations at fixed locations and mobile terminals. In most cases, it is a line-of-sight scenario, and the channel situation is relatively simple. The main body of vehicle-to-vehicle communication is the vehicle-mounted mobile communication platform. The vehicle-mounted platform has communication activities with other vehicle-mounted platforms and communication network base stations in existing infrastructure in the traffic environment. At the same time, the vehicle itself moves at a high speed in traffic flow, urban environment, and high-speed road environment, with diverse movement trajectories and relatively complex channel conditions. In order to obtain channel parameters such as received power, path loss, and multipath, people have studied vehicle-to-vehicle channels from the aspects of network characteristics, antenna design, and channel characteristics of vehicle-to-vehicle communication. The current channel-related research includes research results on network communication and physical layer channels. The channel model of vehicle-to-vehicle communication can be divided into two types: statistical model and deterministic model, among which the deterministic channel model is mainly based on ray tracing method.

[0003] The ray tracing method is a more general channel modeling method. It is a deterministic channel modeling method based on geometric optics, consistent diffraction theory, radio wave propagation mechanism and basic theory. Channel prediction can be performed when the geometric modeling of the wireless communication environment, the electrical parameters in 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 has a Sub-6 GHz multi-band wireless channel measurement system and modeling method. The patent application with 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) building a multi-band wireless channel measurement system; (2) measuring the outdoor scene layout and establishing a simulated three-dimensional scene model; (3) performing fixed-point measurement on the medium in the outdoor scene; obtaining a fixed-point simulation result based on the fixed-point measurement result; (5) calibrating the medium parameters of the simulated three-dimensional scene model according to the simulation result; performing continuous channel measurement in the outdoor scene; obtaining simulation parameters according to the continuous channel measurement result based on the optimal parameter search method; (6) performing global ray simulation tracing on the calibrated simulated three-dimensional scene model, and matching the model parameters to obtain a Sub-6 GHz multi-band wireless channel model. The method can accurately reflect the characteristics of the outdoor scene, but does not consider the impact of dynamic objects such as vehicles in the scene on the channel, and cannot take the geometric shape of the vehicle into account in the prediction calculation of the vehicle-to-vehicle channel. At the same time, it lacks the corresponding relationship between the vehicle's driving information and the spectrum characteristics. The data measured by this method cannot completely restore the vehicle driving information and channel characteristics in the vehicle-to-vehicle channel. Summary of the invention

[0005] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a vehicle-to-vehicle channel measurement system and method combined with a carrier phase differential positioning module, wherein an antenna, a signal source, a power amplifier, a vector network analyzer, and other equipment used to measure channel characteristics are installed on a measuring vehicle; the carrier phase differential positioning module is installed on the measuring vehicle and debugged; vehicle-to-vehicle communication scenarios are measured to obtain channel characteristic data and vehicle driving information data; a data processing program is used to construct a scene frame based on the channel characteristic data and the vehicle driving information data, aiming to solve the vehicle driving information and channel characteristic measurement in vehicle-to-vehicle channel measurement, and construct the correspondence between driving information channel characteristics.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A vehicle-to-vehicle channel measurement system combined with a carrier phase differential positioning module comprises: a transmitting vehicle and a receiving vehicle for channel measurement, wherein a mobile power station, a power amplifier, a signal generator, a first computer and a first carrier phase differential positioning module are arranged in the transmitting vehicle, and a transmitting antenna and a first carrier phase differential positioning antenna are installed on the top of the transmitting vehicle; the mobile power station is respectively connected to the power supply ends of the power amplifier and the signal generator through a power line, the radio frequency output end of the signal generator is connected to the signal input end of the power amplifier through a microwave transmission line, and the signal output end of the power amplifier is connected to the signal input end 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 of the transmitting vehicle through the first carrier phase differential positioning module;

[0008] A vector network analyzer, a second computer and a second carrier phase differential positioning module are installed in the receiving vehicle; a receiving antenna and a second wave 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 network cable; the vector network analyzer and the second carrier phase differential positioning module are connected to the second computer via a 10 Gigabit network cable respectively.

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

[0011] A distance is left between the receiving antenna and the second carrier phase differential positioning antenna to avoid or reduce the horizontal line of sight path of the receiving antenna being blocked by the positioning antenna.

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

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

[0014] Step 1: Configure the channel measurement equipment, install the receiving antenna and the 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; and obtain the required channel characteristic data during the measurement process:

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

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

[0017] Step 4: According to Steps 1 to 3, set the channel measurement equipment parameters and data recording program required before measurement:

[0018] Step 5: According to the settings of steps 1 to 4, measure the channel characteristic data and vehicle driving information data during driving:

[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 a scene frame for vehicle-to-vehicle channel measurement.

[0020] The specific method of step 2 is:

[0021] 2.1 Install the first carrier phase differential positioning module in the transmitting vehicle, and the second carrier phase differential positioning module in the receiving vehicle. Install a pair of first carrier phase differential positioning antennas on the roof of the transmitting vehicle symmetrically about the direction of travel, and keep a distance from the transmitting antenna to avoid or reduce the horizontal line of sight path of the transmitting antenna being blocked by the positioning antenna; install a pair of second carrier phase differential positioning antennas on the roof of the receiving vehicle, and keep a distance from the receiving antenna to avoid or reduce the horizontal line of sight path of the receiving antenna being blocked by the positioning antenna;

[0022] 2.2 Perform the following configurations 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 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 symmetric about the direction of travel", check the operation panels of the first carrier phase differential positioning module and the second carrier phase differential positioning module after the settings are completed, the preheating status of the inertial navigation system of the first carrier phase differential positioning module and the second carrier phase differential positioning module is "preheating completed", the number of available positioning satellites is greater than 10, and the data reporting rate is greater than ten times per second, which means 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: installing the first computer in the transmitting vehicle and the second computer in the receiving vehicle; connecting the first carrier phase differential positioning module to the first computer in the transmitting vehicle, and connecting the second computer to the vector network analyzer and the second carrier phase differential positioning module in the receiving vehicle, respectively, calling the interface function of the vector network analyzer, and using the channel parameter reporting program to configure the frequency sweep parameters of the vector network analyzer n times per second: triggering the frequency sweep data recording of the vector network analyzer n times per second at the moment when each nth group of data in the positioning module report data appears, and writing the data in .mat format as channel characteristic data.

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

[0025] The specific method of step 5 is:

[0026] 5.1 When the receiving vehicle and the transmitting vehicle drive to the starting point of the measurement route in the measurement scene, the second computer starts recording the data reported by the channel parameters, i.e., the channel characteristic data, and then starts the data output of the positioning data recording program, 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 scene, first stop the data output of the 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 step 5.1 and step 5.2.

[0029] The specific method of step 6 is: use any computer to obtain the channel characteristic data and vehicle driving information data obtained in the first computer and the second computer, read the vehicle driving information data and the channel characteristic data through a script program written in MATLAB, match the two sets of data according to UNIX time as indexes, and eliminate 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 into UTM coordinates, and offset them according to the offset set by the preset construction scene frame; use a script program written in PYTHON to Dynamic objects (vehicles, etc.) are spliced ​​with static scenes (ground buildings, etc.) according to the vehicle orientation recorded in the matched data to obtain the simulation scene file in each scene frame in .stl format; a script program written in PYTHON is used to write the antenna parameter file in each scene frame in .csv format according to the vehicle position in the matched data, the offset of the position recorded by the relative positioning system of the roof-mounted antenna during measurement, and the antenna parameters itself. The file contains the UTM coordinates of the antenna and the basic parameters of the receiving and transmitting antennas; finally, a scene frame of vehicle-to-vehicle channel measurement at each moment containing the simulation scene, antenna parameters, and channel characteristic data is obtained.

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

[0031] The present invention configures a channel measurement device including a receiving antenna, a transmitting antenna, a signal generator, a power amplifier and a vector network analyzer to obtain channel characteristic data in a vehicle-to-vehicle channel scenario; configures a carrier phase differential positioning module and a positioning antenna to obtain vehicle driving information data, and establishes a scene frame based on these two types of data, and uses the scene frame to establish a data association between the channel characteristic data and the vehicle driving information in the vehicle-to-vehicle channel measurement, and a channel measurement method for ray tracing algorithm research; the data is more organized, and a variety of simulation scenarios within the measurement time period can be established more quickly, and more convenience is obtained in data processing and simulation calculations. The scene frame contains accurate information such as vehicle posture and position, and it is also convenient to select and use or mix high-precision scene models and low-precision scene models when combining and building simulation scenarios. Therefore, this method has greater flexibility and versatility when used for ray tracing simulation. It can be used for research and production in the fields of wireless channel models, algorithms, traffic control, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of vehicle-to-vehicle channel measurement using a carrier phase differential positioning module provided by an embodiment of the present invention.

[0033] Figure 2 is a diagram of the equipment connection in the receiving and sending vehicle provided by an embodiment of the present invention; wherein, Figure 2(a) is the equipment connection diagram in the launch vehicle. Figure 2 (b) is the equipment connection diagram in the receiving vehicle.

[0034] Figure 3 : is a schematic diagram of the installation position of the roof antenna provided by an embodiment of the present invention; wherein, Figure 3 (a) Figure 3 (b) Side views of the roof antenna installation locations of the transmitting vehicle and the receiving vehicle, respectively;

[0035] Figure 3 (c) Figure 3 (d) Top views of the roof antenna installation positions of the transmitting vehicle and the receiving vehicle, respectively.

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

[0037] Figure 5 It is a schematic diagram of a simulation environment provided by an embodiment of the present invention.

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

[0039] Figure 7 It is a power spectrum diagram obtained by measurement provided by an embodiment of the present invention.

[0040] Figure 8 It is an absolute speed diagram of a vehicle traveling obtained by measurement according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0042] The present invention mainly utilizes the existing channel measurement equipment and carrier phase real-time positioning module to obtain channel parameter data and vehicle driving information data during the channel measurement process of vehicle-to-vehicle communication scenarios, and constructs a scene frame with the channel characteristic data and vehicle driving information data, which is finally used for ray tracing simulation calculation. Figure 1 Flowchart for measuring vehicle-to-vehicle channel using carrier phase real-time positioning system.

[0043] A vehicle-to-vehicle channel measurement system combined with a carrier phase differential positioning module, see Figure 2, including: a transmitting vehicle and a receiving vehicle for channel measurement, wherein a mobile power station, a power amplifier, a signal generator, a first computer and a first carrier phase differential positioning module are arranged in the transmitting vehicle, and a transmitting antenna and a first carrier phase differential positioning antenna are installed on the top of the transmitting vehicle; the mobile power station is connected to the power supply ends of the power amplifier and the signal generator respectively through power lines, the radio frequency output end of the signal generator is connected to the signal input end of the power amplifier through a microwave transmission line, and the signal output end of the power amplifier is connected to the signal input end 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 of the transmitting vehicle through the first carrier phase differential positioning module;

[0044] A vector network analyzer, a second computer and a second carrier phase differential positioning module are installed in the receiving vehicle; a receiving antenna and a second wave 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 carrier phase differential positioning antenna on the top of the receiving vehicle are arranged in pairs and are symmetrical about the direction of travel. Figure 2 , Figure 3 shown.

[0046] A distance is left between the transmitting antenna and the first carrier phase differential positioning antenna to avoid or reduce the horizontal line of sight path of the transmitting antenna being blocked by the positioning antenna.

[0047] A distance is left between the receiving antenna and the second carrier phase differential positioning antenna to avoid or reduce the horizontal line of sight path of the receiving antenna being blocked by the positioning antenna.

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

[0049] A vehicle-to-vehicle channel measurement method combined with a carrier phase differential positioning module, characterized in that it comprises the following steps, see 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 the 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;

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

[0052] 2.1 Install the first carrier phase differential positioning module in the transmitting vehicle, install the second carrier phase differential positioning module in the receiving vehicle, and install a pair of first carrier phase differential positioning antennas on the roof of the transmitting vehicle symmetrically about the direction of travel, and keep a distance from the transmitting antenna to avoid or reduce the horizontal line of sight path of the transmitting antenna being blocked by the positioning antenna, see Figure 3 (a) Figure 3 (b) A pair of second carrier phase differential positioning antennas are installed on the roof of the receiving vehicle, keeping a distance from the receiving antenna to avoid or reduce the horizontal line of sight path of the receiving antenna being blocked by the positioning antenna, see Figure 3 (c) Figure 3 (d);

[0053] 2.2 Perform the following configurations 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 symmetric about the direction of travel", check the operation panels of the first carrier phase differential positioning module and the second carrier phase differential positioning module after the settings are completed, the preheating status of the inertial navigation system of the first carrier phase differential positioning module and the second carrier phase differential positioning module is "preheating completed", the number of available positioning satellites is greater than 10, and the data reporting rate is greater than ten times per second, which means that the first carrier phase differential positioning module and the second carrier phase differential positioning module are operating normally.

[0054] The reference coordinate system set in step 2.2 adopts the WGS84 coordinate system.

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

[0056] The first computer is installed in a transmitting vehicle, and the second computer is installed in a receiving vehicle; the first carrier phase differential positioning module is communicatively connected to the first computer in the transmitting vehicle, and the second computer is communicatively connected to the vector network analyzer and the second carrier phase differential positioning module in the receiving vehicle, respectively, the interface function of the vector network analyzer is called, and the channel parameter reporting program is used to configure the frequency sweeping parameters of the vector network analyzer n times per second: the frequency sweeping data recording of the vector network analyzer n times per second is triggered by the moment when each nth group of data in the positioning module reporting data appears, and the data is written out in .mat format as channel characteristic data.

[0057] Step 4: According to Steps 1 to 3, set the channel measurement equipment parameters and data recording program required before measurement:

[0058] Drive the transmitting vehicle and the receiving vehicle to the starting point of the measurement route in the measurement scene, 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 and the channel parameter reporting program that calls the vector network analyzer interface in the second computer respectively.

[0059] Step 5: According to the settings of steps 1 to 4, measure the channel characteristic data and vehicle driving information data during driving:

[0060] 5.1 When the receiving vehicle and the transmitting vehicle drive to the starting point of the measurement route in the measurement scene, the second computer starts recording the data reported by the channel parameters, i.e., the channel characteristic data, and then starts the data output of the positioning data recording program, 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 scene, first stop the data output of the 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 step 5.1 and step 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 a scene frame for vehicle-to-vehicle channel measurement:

[0064] Use any computer to obtain the channel characteristic data and vehicle driving information data obtained in the first computer and the second computer, read the vehicle driving information data and channel characteristic data through a script program written in MATLAB, match the two sets of data according to the UNIX time as an index, and eliminate the invalid data that cannot be matched according to the time due to the unstable return rate; use the script program written in PYTHON to convert the WGS84 coordinates recorded in the matched data into UTM coordinates, and offset them according to the offset set by the preset construction scene frame; use the script program written in PYTHON to splice the dynamic objects (vehicles, etc.) with the static scenes (ground buildings, etc.) according to the vehicle orientation posture recorded in the matched data to obtain the simulation scene file in each scene frame in .stl format; use the script program written in PYTHON to write the antenna parameter file in each scene frame in .csv format according to the vehicle position in the matched data, the offset of the relative positioning system recorded position of the roof-mounted antenna during measurement, and the antenna parameters themselves. The file contains the UTM coordinates of the antenna and the basic parameters of the receiving and transmitting antennas; finally, a scene frame of vehicle-to-vehicle channel measurement at each moment containing the simulation scene, antenna parameters and channel characteristic data 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 participating in the composition 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, and z represent the coordinate values ​​of the 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 contains the index values ​​of the three points that make up each face, the normal of the face, and the electrical parameter material corresponding to the face; (3) Record the information of all edges in the simulation scene model in the edge file Corner.csv, which contains the index of the points that make up each edge and the associated information of the index of the faces on both sides of the edge

[0067] Configure ray tracing simulation parameters, and configure the ray emission number, reflection order, transmission order, diffraction order, receiving sphere radius and other parameters of the ray tracing algorithm according to the simulation scenario;

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

[0069] Verify the accuracy of the algorithm by comparing and analyzing the channel parameters obtained by ray tracing calculations with the values ​​in the channel characteristic data to verify the accuracy of the ray tracing algorithm.

[0070] Process the message reported by the carrier phase differential positioning module, and convert the vehicle's driving information data into UNIX time, longitude, latitude, and real-time vehicle speed (such as Figure 8 ) The vehicle body orientation angle is written out in a .csv format file.

[0071] Call the vector network analyzer interface and write the channel parameter data into a .mat file according to the three matrices of time, xAxisInfo, and PowerSpectrum. Among them, PowerSpectrum is the power spectrum data obtained by the frequency sweep measurement, and its value represents the power intensity received by the receiving end. Time is all the UNIX time of recording data during the measurement process, and a total of t moments are recorded. xAxisInfo records the frequency points contained in the frequency sweep data, and a total of f frequency points are recorded, which correspond to f×t power data in PowerSpectrum.

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

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

[0074] 2) Configure the data processing program on the two computers to ensure that the program completes the specified functions;

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

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

[0077] Perform ray tracing simulation verification:

[0078] When building a scene frame, use static scenes and dynamic object models such as Figure 4 , Figure 5 shown.

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

[0080] Convert the scene model in the scene frame into an acceleration structure file, select appropriate ray tracing simulation parameters, and use ray tracing simulation to obtain the predicted received power. Select 5.9149975GHz as the simulation prediction frequency point, and compare the simulation prediction results with the measurement results. Figure 7 As shown in the figure, RT is the received power value predicted by ray tracing simulation; power is the received power value in actual measurement. The root mean square error between the predicted result and the measured value is 11.59 dB, which meets the accuracy requirements of the ray algorithm applied 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A vehicle-to-vehicle channel measurement system combined with a carrier phase differential positioning module, comprising: A transmitting vehicle and a receiving vehicle for channel measurement, characterized in that: The transmitting vehicle is provided with a mobile power station, a power amplifier, a signal generator, a first computer and a first carrier phase differential positioning module, and a transmitting antenna and a first carrier phase differential positioning antenna are installed on the top of the transmitting vehicle; the mobile power station is connected to the power supply ends of the power amplifier and the signal generator respectively through power lines, the radio frequency output end of the signal generator is connected to the signal input end of the power amplifier through a microwave transmission line, and the signal output end of the power amplifier is connected to the signal input end 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 through the first carrier phase differential positioning module; A vector network analyzer, a second computer and a second carrier phase differential positioning module are installed in the receiving vehicle; a receiving antenna and a second wave 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.

2. The vehicle-to-vehicle channel measurement system combined with a carrier phase differential positioning module according to claim 1, characterized in that: The first carrier phase differential positioning antenna on the top of the transmitting vehicle and the second carrier phase differential positioning antenna on the top of the receiving vehicle are both arranged in pairs and are symmetrical with respect to the left and right of the traveling direction.

3. A vehicle-to-vehicle channel measurement system combined with a carrier phase differential positioning module according to claim 1 or 2, characterized in that: A spacing is left between the transmitting antenna and the first carrier phase differential positioning antenna to avoid or reduce the horizontal line of sight path of the transmitting antenna being blocked by the positioning antenna; A distance is left between the receiving antenna and the second carrier phase differential positioning antenna to avoid or reduce the horizontal line of sight path of the receiving antenna being blocked by the positioning antenna.

4. The vehicle-to-vehicle channel measurement system combined with a carrier phase differential positioning module according to claim 1, characterized in that: The first carrier phase differential positioning module is connected to the first computer via a 10 Gigabit network cable; the vector network analyzer and the second carrier phase differential positioning module are connected to the second computer via a 10 Gigabit network cable respectively.

5. A vehicle-to-vehicle channel measurement method combined with a carrier phase differential positioning module, characterized in that: The specific steps include: Step 1: Configure the channel measurement equipment, install the receiving antenna and the 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 reporting rates for recording vehicle driving information data during the measurement process: Step 3: Based on the configurations of Steps 1 and 2, synchronize the carrier phase differential positioning module with the feedback from the vector network analyzer: Step 4: According to Steps 1 to 3, set the channel measurement equipment parameters and data recording program required before measurement: Step 5: According to the settings of steps 1 to 4, measure the channel characteristic data and vehicle driving information data during driving: Step 6: Use a data processing program to process the channel characteristic data and vehicle driving information data measured in step 5 to obtain a scene frame for vehicle-to-vehicle channel measurement.

6. The vehicle-to-vehicle channel measurement method according to claim 5, characterized in that: The specific method of step 2 is: 2.1 Install the first carrier phase differential positioning module in the transmitting vehicle, install the second carrier phase differential positioning module in the receiving vehicle, and install a pair of first carrier phase differential positioning antennas on the roof of the transmitting vehicle symmetrically about the direction of travel, and keep a distance from the transmitting antenna to avoid or reduce the horizontal line of sight path of the transmitting antenna being blocked by the positioning antenna; A pair of second carrier phase differential positioning antennas are installed on the roof of the receiving vehicle, keeping a distance from the receiving antenna to avoid or reduce the horizontal line of sight path of the receiving antenna being blocked by the positioning antenna; 2.2 Perform the following configurations 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 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 symmetric about the direction of travel", check the operation panels of the first carrier phase differential positioning module and the second carrier phase differential positioning module after the settings are completed, the inertial navigation system preheating status of the first carrier phase differential positioning module and the second carrier phase differential positioning module is "preheating completed", the number of available positioning satellites is greater than 10, and the data reporting rate is greater than ten times per second, which means that the first carrier phase differential positioning module and the second carrier phase differential positioning module are operating normally.

7. The vehicle-to-vehicle channel measurement method according to claim 5, characterized in that: The specific method of step 3 is: installing the first computer in the transmitting vehicle and the second computer in the receiving vehicle; connecting the first carrier phase differential positioning module to the first computer in the transmitting vehicle, and connecting the second computer to the vector network analyzer and the second carrier phase differential positioning module in the receiving vehicle, respectively, calling the interface function of the vector network analyzer, and using the channel parameter reporting program to configure the frequency sweep parameters of the vector network analyzer n times per second: triggering the frequency sweep data recording of the vector network analyzer n times per second at the moment when each nth group of data in the positioning module report data appears, and writing the data in .mat format as channel characteristic data.

8. The vehicle-to-vehicle channel measurement method according to claim 5, characterized in that: The specific method of step 4 is: drive the transmitting vehicle and the receiving vehicle to the starting point of the measurement route in the measurement scene, set the signal generator parameters and the power amplifier parameters, and respectively start the carrier phase differential positioning data recording program in the first computer and the second computer and the channel parameter reporting program that calls the vector network analyzer interface in the second computer.

9. The vehicle-to-vehicle channel measurement method according to claim 5, characterized in that: The specific method of step 5 is: 5.1 When the receiving vehicle and the transmitting vehicle drive to the starting point of the measurement route in the measurement scene, the second computer starts recording the data reported by the channel parameters, i.e., the channel characteristic data, and then starts the data output of the positioning data recording program, i.e., the vehicle driving information data, through the command line; 5.2 When the two vehicles reach the end position of the measurement scene, first stop the data output of the 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 step 5.1 and step 5.

2.

10. The vehicle-to-vehicle channel measurement method according to claim 5, characterized in that: The specific method of step 6 is: using any computer to obtain the channel characteristic data and vehicle driving information data obtained in the first computer and the second computer, reading the vehicle driving information data and the channel characteristic data through a script program written in MATLAB, matching the two sets of data according to UNIX time as indexes, and eliminating invalid data that cannot be matched according to time due to unstable return rate; using a script program written in PYTHON to convert the WGS84 coordinates recorded in the matched data into UTM coordinates, and offset according to the offset set by the preset construction scene frame; Using a script program written in PYTHON, dynamic objects (vehicles, etc.) are spliced ​​with static scenes (ground buildings, etc.) according to the vehicle orientation posture recorded in the matched data to obtain a simulation scene file in each scene frame in .stl format; using a script program written in PYTHON, the antenna parameter file in each scene frame in .csv format is written according to the vehicle position in the matched data, the offset of the position recorded by the relative positioning system of the roof-mounted antenna during measurement, and the antenna parameters itself. The file contains the UTM coordinates of the antenna and the basic parameters of the receiving and transmitting antennas; finally, a scene frame of vehicle-to-vehicle channel measurement at each moment containing the simulation scene, antenna parameters, and channel characteristic data is obtained.

Images