An anechoic chamber multi-probe amplitude and phase calibration method for whole vehicle OTA test

Abstract

The application relates to a darkroom multi-probe amplitude and phase calibration method for whole vehicle OTA testing, and belongs to the technical field of communication system monitoring and testing. The method is configured with a whole vehicle bearing position, a multi-probe array, a channel simulator, an amplitude and phase adjustment branch, a no-load calibration piece and a vehicle occupying body in a darkroom, a multi-probe channel table and a vehicle shielding relationship table are established, a no-load reference response and an occupying calibration response are collected respectively, a vehicle shielding amplitude and phase offset is generated through amplitude registration and phase registration, and an amplitude and phase calibration table is formed according to a vehicle posture angle, a working frequency point, a polarization branch, a probe number and a calibration receiving point partition index in combination with a channel amplitude and phase correction amount.

Description

Technical Field

[0001] This invention relates to the field of wireless communication testing and monitoring technology, and in particular to an anechoic chamber multi-probe amplitude and phase calibration method for over-the-air (OTA) testing of vehicles. Background Technology

[0002] Over-the-air (OTA) testing of wireless communication devices falls under the field of communication system monitoring and testing technology. It is typically used in an anechoic chamber environment to evaluate the transmission, reception, and multi-antenna communication performance of the device under test (DUT) in a wireless link. With the development of in-vehicle communication, intelligent connected vehicles, and massive MIMO technology, OTA testing of complete vehicles increasingly requires testing in an anechoic chamber using a test system composed of a multi-probe array, channel simulator, amplitude and phase adjustment branch, and test controller to test the wireless communication performance of vehicles under different vehicle attitude angles, operating frequencies, and polarization branches.

[0003] Existing multi-probe OTA testing systems typically construct a predetermined wireless channel environment within an anechoic chamber using multiple anechoic probes, and calibrate each multi-probe channel using a channel simulator and amplitude / phase adjustment branches. For example, patent application CN106412953A discloses a multi-probe testing system and its calibration method and apparatus. This system calibrates both the active and passive components of the multi-probe testing system to obtain the path loss values ​​of each test channel, and compensates for these path loss values ​​to ensure that multiple test channels meet calibration requirements within the test area. This type of technology can process the channel loss, channel consistency, and pre-test calibration data of the multi-probe OTA testing system itself, and is applicable to calibration scenarios for general MIMO OTA testing systems.

[0004] However, in the anechoic chamber environment for over-the-air (OTA) testing of whole vehicles, the object under test is no longer a small communication terminal with a relatively simple spatial structure, but a whole vehicle with a vehicle body outline, window area, metal boundary area, internal reflective components, and multiple vehicle communication antenna mounting locations. When the vehicle is in the anechoic chamber testing area, the propagation path between different anechoic chamber probes and different spatial areas of the vehicle will be affected by vehicle body obstruction, vehicle body boundary scattering, and the incident path inside the chamber; at the same time, the propagation path state between the same anechoic chamber probe and the same spatial area of ​​the vehicle may also change under different vehicle attitude angles. The resulting amplitude and phase changes are not entirely equivalent to the channel amplitude and phase errors of the multi-probe testing system itself.

[0005] Existing multi-probe OTA calibration methods primarily focus on calibrating path loss or amplitude-phase consistency within the test system channels themselves. Their calibration data typically corresponds to system channel parameters such as anechoic chamber probes, channel simulator ports, operating frequencies, or polarization branches. When used for large-scale MIMO OTA testing of vehicles, these methods struggle to distinguish between the amplitude-phase errors of the multi-probe test system's own channels and factors introduced by vehicle structure such as obstruction, boundary scattering, and in-cabin incident amplitude-phase shift. Furthermore, they fail to correlate calibration results with changes in vehicle attitude angles, operating frequencies, polarization branches, probe positions, and propagation paths between different spatial regions of the vehicle. Directly applying general multi-probe MIMO OTA calibration data to vehicle OTA testing may result in a mismatch between the calibration compensation and the actual spatial propagation state of the vehicle, thus affecting the accuracy and consistency of subsequent vehicle wireless communication test data.

[0006] Therefore, in the OTA anechoic chamber multi-probe calibration of a vehicle, how to distinguish the amplitude and phase errors of the multi-probe test system's own channels from the occlusion, boundary scattering, and incident amplitude and phase shift introduced by the vehicle structure, and how to obtain amplitude and phase correction basis that matches the vehicle attitude angle, operating frequency, polarization branch, probe position, and the entire vehicle space area, has become the main technical problem that needs to be solved in this field. Summary of the Invention

[0007] To overcome the aforementioned technical deficiencies, the present invention aims to provide a multi-probe amplitude and phase calibration method for anechoic chamber testing of vehicles. This invention configures a multi-probe array, an unloaded calibration component, and a vehicle placeholder in a large-scale MIMO vehicle OTA anechoic chamber testing environment. It acquires the vehicle attitude angle and configures the operating frequency and polarization branch. The unloaded reference response and the placeholder calibration response are collected respectively. Combined with a preset reference response, a vehicle occlusion relationship table, non-adjacent calibration channel groups, and amplitude and phase registration of corresponding numbered calibration receiving points, the channel amplitude and phase correction and vehicle occlusion amplitude and phase offset are determined. An amplitude and phase calibration table is generated, indexed by vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiving point partition. This solves the problem in the prior art where multi-probe calibration in a vehicle OTA anechoic chamber struggles to distinguish between the amplitude and phase errors of the test system's own channels and the occlusion, boundary scattering, and incident amplitude and phase offset introduced by the vehicle structure.

[0008] This invention discloses a method for anechoic chamber multi-probe amplitude and phase calibration for over-the-air (OTA) testing of whole vehicles, comprising:

[0009] The dark chamber is equipped with a vehicle bearing position, multi-probe array, channel simulator, amplitude and phase adjustment branch, no-load calibration component, vehicle occupant and test controller for large-scale MIMO vehicle OTA testing. The multi-probe array includes multiple dark chamber probes, each of which is assigned a probe number. The vehicle occupant is the equivalent scattering body of the vehicle under test or the whole vehicle.

[0010] Configure the operating frequency and polarization branch, and obtain the vehicle attitude angle of the vehicle occupier;

[0011] The unloaded calibration component and the vehicle occupant are equipped with corresponding numbered calibration receiving points. Each calibration receiving point has a calibration receiving point number and a calibration receiving point partition. The calibration receiving point partition includes the vehicle antenna installation area, the vehicle body boundary area, and the cabin scattering area.

[0012] Establish a multi-probe channel table. Each multi-probe channel in the multi-probe channel table corresponds to an anechoic chamber probe, a channel simulator port, an amplitude and phase adjustment branch, a polarization branch, and at least one operating frequency.

[0013] Establish a vehicle occlusion relationship table. The table entries include vehicle attitude angle, probe number, calibration receiver point number, and path marker. The path marker includes unobstructed path, boundary occlusion path, and in-cabin incident path.

[0014] Generate non-adjacent channels to be calibrated based on the vehicle occlusion relationship table;

[0015] Place the unloaded calibration component in the vehicle's load position, load the orthogonal calibration sequence onto the channel group to be calibrated, and collect the unloaded reference response;

[0016] Replace the unloaded calibration component with a vehicle occupant, and collect the occupant calibration response under the same vehicle attitude angle, the same operating frequency, the same polarization branch, and the same group of channels to be calibrated.

[0017] The channel amplitude and phase correction amount is determined based on the no-load reference response and the preset reference response. The occupancy calibration response under the corresponding numbered calibration receiving point is registered in amplitude and phase with the no-load reference response to generate the vehicle occupancy amplitude and phase offset.

[0018] Amplitude and phase correction values ​​are generated based on channel amplitude and phase correction values ​​and vehicle occlusion amplitude and phase offset values, and an amplitude and phase calibration table is formed according to vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiver point partition index.

[0019] Preferably, establishing a vehicle occlusion relationship table includes:

[0020] Obtain the outer contour area, window area, and metal boundary area of ​​the vehicle occupier;

[0021] Determine the connection path between each anechoic chamber probe and each calibration receiver point in the multi-probe array;

[0022] Perform region matching between the connecting path and the outer contour area, window area, and metal boundary area;

[0023] Based on the region matching results, the connection path is marked as an unobstructed path, a boundary obstructed path, or an in-cabin incident path, and the corresponding path marking is saved with the vehicle attitude angle, probe number, and calibration receiver point number.

[0024] Preferably, determining the calibration receiving point partition includes:

[0025] The vehicle antenna installation area is determined based on the installation coordinates of the vehicle's onboard communication antenna within the vehicle's occupant.

[0026] The vehicle body boundary area is determined based on the outer contour area, the window area, and the metal boundary area.

[0027] The cabin scattering zone is determined based on the installation coordinates of the cabin communication module in the vehicle occupant and the coordinates of the cabin reflective components.

[0028] Establish a one-to-one mapping relationship between each calibration receiving point number and its corresponding calibration receiving point partition.

[0029] Preferably, the calibration receiving points with corresponding numbers are provided on the unloaded calibration component and the vehicle occupant, including:

[0030] Set up a first-class calibration receiving point, a second-class calibration receiving point, and a third-class calibration receiving point on the unloaded calibration component;

[0031] The first type of calibration receiving point corresponds to the vehicle antenna installation area, the second type of calibration receiving point corresponds to the vehicle body boundary area, and the third type of calibration receiving point corresponds to the cabin scattering area.

[0032] On the vehicle occupant, calibration receiving points are set up one by one, corresponding to the first type of calibration receiving point, the second type of calibration receiving point, and the third type of calibration receiving point.

[0033] Establish a coordinate registration relationship between two calibration receiving points with the same number.

[0034] Preferably, generating a group of non-adjacent channels to be calibrated based on the vehicle occlusion relationship table includes:

[0035] Select a multi-probe channel from the multi-probe channel table. The probe numbers corresponding to the multi-probe channels are not adjacent to each other according to the spatial arrangement order of the multi-probe array.

[0036] Query the path markers corresponding to the selected multi-probe channels under the same vehicle attitude angle, the same operating frequency, and the same calibration receiver point number;

[0037] When two selected multi-probe channels correspond to the same calibration receiving point number and are both boundary obstruction paths or both are in-cabin incident paths, one of the multi-probe channels will be removed from the current calibration channel group.

[0038] The removed multi-probe channels are incorporated into the next group of channels to be calibrated.

[0039] Preferably, loading an orthogonal calibration sequence into the group of channels to be calibrated includes:

[0040] Generate orthogonal calibration sequences for each multi-probe channel within the same group of channels to be calibrated;

[0041] The orthogonal calibration sequence includes a channel identification segment and an occlusion verification segment;

[0042] Generate channel identification segments based on probe numbers;

[0043] Under the same vehicle attitude angle, the same operating frequency and the same calibration receiver number, the occlusion verification segment is generated together with the corresponding path mark and the corresponding probe number in the vehicle occlusion relationship table.

[0044] Within the same group of channels to be calibrated, any two multi-probe channels have different channel identification segments and different occlusion verification segments.

[0045] Preferably, separating the channel amplitude and phase responses of each multi-probe channel from the unloaded reference response and the occupancy calibration response includes:

[0046] Based on the channel identification segment, channel matching is performed on the no-load reference response to obtain the no-load initial amplitude and phase response corresponding to each multi-probe channel;

[0047] Based on the channel identification segment, channel matching is performed on the occupancy calibration response to obtain the occupancy initial amplitude and phase response corresponding to each multi-probe channel;

[0048] Based on the occupancy verification segment, path marking matching is performed on the occupancy initial amplitude and phase responses under the same vehicle attitude angle, the same operating frequency, the same probe number, and the same calibration receiver number;

[0049] When the path marker matching result matches the path marker in the vehicle occlusion relationship table, the unloaded initial amplitude-phase response is used as the unloaded channel amplitude-phase response of the corresponding multi-probe channel, and the occupied initial amplitude-phase response is used as the occupied channel amplitude-phase response of the corresponding multi-probe channel.

[0050] When the path marker matching result is inconsistent with the corresponding path marker in the vehicle occlusion relationship table, the corresponding multi-probe channel will be included in the channel set to be recalibrated.

[0051] Preferably, after generating the group of channels to be calibrated, the method further includes establishing a calibration task queue;

[0052] The calibration task queue divides the channels to be calibrated into unobstructed calibration tasks, boundary obstructed calibration tasks, and in-cabin incident calibration tasks according to the path markings.

[0053] Unobstructed calibration tasks correspond to unobstructed paths;

[0054] Boundary occlusion calibration task corresponding to the boundary occlusion path;

[0055] The in-cabin incidence calibration task corresponds to the in-cabin incidence path.

[0056] Each calibration task in the calibration task queue records the vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiver number.

[0057] Preferably, when performing boundary shielding calibration and intra-cabin incidence calibration tasks, the method further includes:

[0058] Acquire the first occupancy calibration response at the current vehicle attitude angle;

[0059] Acquire the second placeholder calibration response at the vehicle attitude angle adjacent to the current vehicle attitude angle in the calibration task queue;

[0060] Determine the path markers corresponding to the first and second placeholder calibration responses, respectively;

[0061] When the two path markings are inconsistent, the interval between the current vehicle attitude angle and the attitude angle of the vehicle adjacent to the current vehicle attitude angle is marked as the interval to be supplemented for calibration.

[0062] Preferably, when acquiring the no-load reference response and the occupancy calibration response, the reference monitoring channel is also enabled;

[0063] The main radiation direction of the anechoic chamber probe corresponding to the reference monitoring channel does not point towards the vehicle's load-bearing area;

[0064] The reference monitoring channel and the channel group to be calibrated are simultaneously loaded with the reference calibration sequence;

[0065] Based on the monitoring responses of the reference monitoring channel during the acquisition of the no-load reference response and the acquisition of the occupancy calibration response, the no-load reference response and the occupancy calibration response are subjected to homogeneous drift correction.

[0066] Preferably, the homogeneous drift correction of the no-load reference response and the occupancy calibration response includes:

[0067] Acquire the first monitoring response of the reference monitoring channel during the acquisition of the no-load reference response;

[0068] Acquire the second monitoring response of the reference monitoring channel during the acquisition of the occupancy calibration response;

[0069] The drift response is determined based on the first and second monitoring responses;

[0070] When the drift response satisfies the drift correction condition determined by repeated measurements, the no-load reference response and the placeholder calibration response are corrected based on the drift response.

[0071] Preferably, after performing homologous drift correction, the method further includes:

[0072] The occupancy calibration response after homologous drift correction is amplitude-registered and the no-load reference response after homologous drift correction is phase-registered.

[0073] When the amplitude registration result or phase registration result does not meet the consistency condition determined by the repeated measurement results of the corresponding calibration receiving point, the corresponding probe number, operating frequency, polarization branch, vehicle attitude angle and calibration receiving point number are written into the local recalibration list.

[0074] The corresponding multi-probe channel is determined based on the probe number, operating frequency, and polarization branch in the local recalibration list, and the corresponding occupancy calibration response is re-acquired under the vehicle attitude angle and calibration receiver number in the local recalibration list.

[0075] Preferably, forming the amplitude-phase calibration table includes:

[0076] Generate an empty channel correction sub-table, a vehicle obstruction offset sub-table, a receiver point partition sub-table, and a recalibration status sub-table;

[0077] The idle channel calibration sub-table stores the channel amplitude and phase calibration values;

[0078] The vehicle occlusion offset sub-table stores the vehicle occlusion amplitude and phase offset;

[0079] The receiving point partition sub-table stores the correspondence between calibration receiving point numbers and calibration receiving point partitions;

[0080] The recalibration status sub-table includes fields for probe number, operating frequency, polarization branch, vehicle attitude angle, calibration receiver number, local recalibration status, and isolation channel status.

[0081] Preferably, when the actual vehicle attitude angle of the vehicle under test does not match the vehicle attitude angle index in the amplitude-phase calibration table, the method further includes:

[0082] For the probe number and calibration receiver number of the amplitude and phase correction amount to be read, determine the path mark corresponding to the actual vehicle attitude angle according to the vehicle occlusion relationship table;

[0083] Select the two vehicle attitude angle indices that are adjacent to the actual vehicle attitude angle;

[0084] For the probe number and calibration receiving point number of the amplitude and phase correction amount to be read, determine the path markers corresponding to two adjacent vehicle attitude angle indices respectively;

[0085] When the path marker corresponding to the actual vehicle attitude angle is consistent with the path markers corresponding to the two adjacent vehicle attitude angle indices, the amplitude and phase correction amount corresponding to the actual vehicle attitude angle is generated based on the amplitude and phase correction amount under the two adjacent vehicle attitude angle indices.

[0086] When the path marker corresponding to the actual vehicle attitude angle is inconsistent with the path marker corresponding to any adjacent vehicle attitude angle index, the actual vehicle attitude angle is written into the set of attitude angles to be supplemented for calibration.

[0087] Preferably, before performing large-scale MIMO vehicle OTA testing, the following steps are also included:

[0088] Load the amplitude and phase calibration table into the test controller;

[0089] The test controller reads the corresponding amplitude and phase correction values ​​from the unloaded channel correction sub-table and the vehicle occlusion offset sub-table according to the vehicle attitude angle, operating frequency, polarization branch, probe number and calibration receiver partition;

[0090] The read amplitude and phase correction values ​​are sent to the amplitude and phase adjustment branch;

[0091] When the isolation channel status field in the recalibration status sub-table is recorded as isolated, the test controller determines the corresponding multi-probe channel based on the probe number field, operating frequency field, and polarization branch field in the recalibration status sub-table, and then masks the corresponding multi-probe channel.

[0092] Compared with existing technologies, the above technical solution has the following advantages:

[0093] 1. This invention can distinguish between the amplitude and phase errors of the multi-probe testing system's own channels and the amplitude and phase offsets introduced by the vehicle structure. By separately acquiring the unloaded reference response corresponding to the unloaded calibration component and the occupant calibration response corresponding to the vehicle occupant, and performing amplitude and phase registration on the corresponding numbered calibration receiving points, the test controller can obtain the channel amplitude and phase correction amount and the vehicle occlusion amplitude and phase offset amount, thereby avoiding misinterpreting occlusion, boundary scattering, and in-cabin incident amplitude and phase changes caused by the vehicle structure as errors inherent in the multi-probe channels. This invention is suitable for anechoic chamber multi-probe amplitude and phase calibration in large-scale MIMO vehicle OTA testing.

[0094] 2. This invention improves the matching between amplitude and phase correction values ​​and the actual spatial propagation path of the vehicle during over-the-air (OTA) testing. It establishes a vehicle occlusion relationship table and establishes a correspondence between vehicle attitude angle, probe number, calibration receiver number, and path marker. This allows the amplitude and phase correction values ​​to be determined not only based on system channel parameters such as anechoic chamber probes, operating frequencies, and polarization branches, but also by combining unobstructed paths, boundary occlusion paths, and in-cabin incident paths. This improves the correspondence between the amplitude and phase correction values ​​and the vehicle's spatial propagation state under different vehicle attitude angles.

[0095] 3. This invention reduces response aliasing caused by adjacent channels and similar obstruction paths during multi-probe parallel calibration. Based on the vehicle obstruction relationship table, this invention generates non-adjacent groups of channels to be calibrated. Under the same calibration receiving point number, it excludes multi-probe channels that share boundary obstruction paths or are both on in-cabin incident paths. This ensures that multi-probe channels within the same calibration group are distinguishable in both spatial arrangement and path marking, thereby improving the accuracy of separating the no-load reference response and the occupied calibration response.

[0096] 4. Improves the ability of orthogonal calibration sequences to identify multi-probe channel responses and occlusion path states. The orthogonal calibration sequence of this invention includes a channel identification segment and an occlusion verification segment. The channel identification segment is used to distinguish multi-probe channels corresponding to different probe numbers, and the occlusion verification segment is generated based on the path marker and probe number. Thus, the orthogonal calibration sequence can not only be used for channel response separation, but also to verify whether the path marker corresponding to the occupancy calibration response is consistent with the vehicle occlusion relationship table, thereby providing a basis for generating the set of channels to be recalibrated.

[0097] 5. This invention reduces erroneous calibration value calls when the vehicle attitude angle does not match the amplitude-phase calibration table. When the actual vehicle attitude angle of the vehicle under test does not match the vehicle attitude angle index in the amplitude-phase calibration table, this invention first determines whether the path marker corresponding to the actual vehicle attitude angle is consistent with that of the adjacent vehicle attitude angle index, and then determines whether to generate the amplitude-phase correction value corresponding to the actual vehicle attitude angle based on the amplitude-phase correction value under the adjacent vehicle attitude angle index; when the path markers are inconsistent, the actual vehicle attitude angle is written into the set of attitude angles to be supplemented for calibration. This avoids mismatches in amplitude-phase correction value calls caused by directly interpolating the attitude angle when the occlusion state changes. Attached Figure Description

[0099] Figure 1 This is a schematic diagram of the system layout for the anechoic chamber multi-probe amplitude and phase calibration method provided in an embodiment of the present invention;

[0100] Figure 2 This is a schematic diagram showing the correspondence between the calibration receiving points of the unloaded calibration component and the vehicle occupant provided in an embodiment of the present invention.

[0101] Figure 3 This is a schematic diagram illustrating the processing flow of the vehicle occlusion relationship table, the channel group to be calibrated, and the orthogonal calibration sequence provided in an embodiment of the present invention.

[0102] Figure 4 This is a schematic diagram illustrating the amplitude and phase calibration table generation, local recalibration, and test loading process provided in an embodiment of the present invention.

[0103] Figure 5 This is a comparison curve of amplitude residuals at different vehicle attitude angles provided in an embodiment of the present invention;

[0104] Figure 6 The image shows a comparison curve of phase residuals at different vehicle attitude angles, as provided in an embodiment of the present invention. Detailed Implementation

[0106] The following is combined Figures 1 to 6 This paper details a method for anechoic chamber multi-probe amplitude and phase calibration for over-the-air (OTA) testing of vehicles. This embodiment belongs to the field of wireless communication testing and monitoring technology, specifically to the wireless link OTA calibration technology within communication system monitoring and testing. It is applicable to the amplitude and phase response calibration of multi-probe channels in anechoic chambers during large-scale MIMO vehicle OTA testing scenarios. It can be used for calibration of multi-probe arrays, channel simulators, amplitude and phase adjustment branches, and the spatial propagation path of the entire vehicle in communication system testing.

[0107] like Figure 1 As shown, this embodiment configures a vehicle carrier space 110, a multi-probe array 120, a channel simulator 130, an amplitude and phase adjustment branch 140, a test controller 150, an unloaded calibration component 200, and a vehicle occupant 300 within an anechoic chamber 100. The multi-probe array 120 includes multiple anechoic chamber probes, each with a unique probe number. The channel simulator 130 has multiple channel simulator ports, and the amplitude and phase adjustment branch 140 is used to apply amplitude and phase correction values ​​to the corresponding multi-probe channels. These amplitude and phase correction values ​​include amplitude correction and phase correction. The test controller 150 is used to control calibration sequence generation, response data acquisition, calibration data calculation, amplitude and phase calibration table generation, and amplitude and phase correction value application. The vehicle occupant 300 can be the actual vehicle under test or the vehicle equivalent scatterer. When the vehicle equivalent scatterer is used, the vehicle equivalent scatterer has at least an outer contour area, a window area, a metal boundary area, an internal reflective component, and an installation position of the vehicle communication antenna corresponding to the vehicle under test, so that it can present the obstruction and scattering boundary related to the propagation path of the whole vehicle in the anechoic chamber 100.

[0108] In this embodiment, the vehicle bearing position 110 can be a turntable bearing position or a fixed bearing position. When the vehicle bearing position 110 is a turntable bearing position, the vehicle attitude angle is given by the turntable's angle encoder; when the vehicle bearing position 110 is a fixed bearing position, the vehicle attitude angle can be given by the azimuth angle of the vehicle occupant 300 relative to the coordinate system of the anechoic chamber 100. The vehicle attitude angle is used to represent the spatial orientation of the vehicle occupant 300 relative to the multi-probe array 120. The operating frequency is used to represent the wireless communication test frequency used in large-scale MIMO vehicle OTA testing. The polarization branch is used to represent the horizontal polarization branch, vertical polarization branch, or other preset polarization branch corresponding to the anechoic chamber probe.

[0109] like Figure 2As shown, both the unloaded calibration component 200 and the vehicle occupant 300 are equipped with corresponding numbered calibration receiving points. Each calibration receiving point has a calibration receiving point number and a calibration receiving point partition. The calibration receiving point partitions include a vehicle antenna mounting area, a vehicle body boundary area, and an in-cabin scattering area. The vehicle antenna mounting area corresponds to the installation area for external vehicle antennas, roof antennas, window antennas, or vehicle communication module antennas; the vehicle body boundary area corresponds to areas such as window edges, metal boundaries, and the outer contour boundaries of the vehicle body; the in-cabin scattering area corresponds to the area near the cockpit communication module installation area, the dashboard area, the area near the seat metal frame, or other in-cabin reflective components.

[0110] In one embodiment, the unloaded calibration component 200 is provided with a first type of calibration receiving point 211, a second type of calibration receiving point 212, and a third type of calibration receiving point 213. The first type of calibration receiving point 211 corresponds to the vehicle antenna mounting area, the second type of calibration receiving point 212 corresponds to the vehicle body boundary area, and the third type of calibration receiving point 213 corresponds to the cabin scattering area. The vehicle occupant 300 is provided with calibration receiving points that correspond one-to-one with the first type of calibration receiving point 211, the second type of calibration receiving point 212, and the third type of calibration receiving point 213. A coordinate registration relationship is established between the unloaded calibration component 200 and two calibration receiving points with the same number in the vehicle occupant 300. The coordinate registration relationship can be achieved through laser positioning, visual calibration, mechanical positioning pins, or turntable reference holes.

[0111] The positional deviation of two calibration receiving points with the same number in the 110 coordinate system of the vehicle's load position can be determined by the test accuracy requirements. For example, the upper limit of the positioning deviation can be determined based on the wavelength corresponding to the operating frequency. The wavelength corresponding to the operating frequency can be determined according to equation (1):

[0112]

[0113] In the formula, This indicates the wavelength corresponding to the operating frequency, in meters (m). This indicates the speed at which electromagnetic waves propagate in air, and the unit is m / s; This indicates the operating frequency, measured in Hz. The positional deviation of the calibration receiver point can be controlled within... Within one-tenth of the accuracy, or controlled within the repeatability error range of the calibration receiving probe positioning device. Taking a working frequency of 3.5GHz as an example, when... Pick At m / s, the operating frequency corresponds to a wavelength of approximately 0.0857 m, and the position deviation of the calibration receiver point can be controlled within approximately 8.57 mm.

[0114] In this embodiment, the test controller 150 establishes a multi-probe channel table. Each multi-probe channel in the multi-probe channel table corresponds to an anechoic chamber probe, a channel simulator port, an amplitude-phase adjustment branch 140, a polarization branch, and at least one operating frequency. The multi-probe channel table can record the probe number, channel simulator port number, amplitude-phase adjustment branch number, polarization branch identifier, operating frequency, probe spatial position, probe main radiation direction, and the spatial arrangement order of the anechoic chamber probe in the multi-probe array 120. This multi-probe channel table is used to ensure that subsequent calibration data can accurately correspond to the actual anechoic chamber probe, channel simulator port, and amplitude-phase adjustment branch 140.

[0115] In this embodiment, the test controller 150 establishes a vehicle occlusion relationship table. The table entries include vehicle attitude angles, probe numbers, calibration receiver point numbers, and path markers. Path markers include unobstructed paths, boundary occlusion paths, and in-cabin incident paths. When establishing the vehicle occlusion relationship table, the outer contour region, window region, and metal boundary region of the vehicle occupant 300 are first acquired. The outer contour region can be determined by the full vehicle 3D model, vehicle body scan point cloud, or vehicle size parameters; the window region can be determined by window boundary coordinates, glass area contours, or window panels in the vehicle 3D model; the metal boundary region can be determined by the vehicle body sheet metal boundary, door edge, pillar region, bumper metal support region, or vehicle body conductive component region.

[0116] The test controller 150 determines the connection path between each anechoic chamber probe and each calibration receiving point in the multi-probe array 120, and performs region matching between the connection path and the outer contour region, the window region, and the metal boundary region. Specifically, the line segment between the phase center of the anechoic chamber probe and the receiving center of the calibration receiving point can be used as the connection path. The outer contour region, the window region, and the metal boundary region are represented as region objects composed of three-dimensional patches, boundary surfaces, or bounding volumes, respectively. The controller then determines whether the connection path intersects, crosses, or falls within the corresponding region object. When a path does not pass through the outer contour area, window area, or metal boundary area, or does not form an obstruction relationship with the vehicle occupier 300, the path is marked as an unobstructed path. When a path intersects the outer contour area, window area, or metal boundary area, and this intersection occurs before propagation from outside the vehicle to the calibration receiver point, the path is marked as a boundary obstruction path. When a path enters the cabin through the window area and reaches the calibration receiver point in the cabin scattering area, or when the path corresponds to an internal reflective component, the path is marked as an internal incident path. The vehicle obstruction relationship table stores the corresponding path markings using the vehicle attitude angle, probe number, and calibration receiver point number.

[0117] In one implementation, the calibration receiving point partitions are determined as follows: the vehicle antenna installation area is determined based on the installation coordinates of the vehicle communication antenna on the vehicle occupier 300; the vehicle body boundary area is determined based on the outer contour area, window area, and metal boundary area; the cabin scattering area is determined based on the installation coordinates of the cockpit communication module and the coordinates of the cabin reflective components on the vehicle occupier 300; and then a one-to-one mapping relationship is established between each calibration receiving point number and its corresponding calibration receiving point partition. This method ensures that the calibration receiving point partitions correspond to the overall vehicle structural features, avoiding indiscriminate placement of points based solely on spatial height or ordinary grids.

[0118] like Figure 3 As shown, the test controller 150 generates non-adjacent calibration channel groups based on the vehicle occlusion relationship table. When generating the calibration channel groups, the test controller 150 selects multi-probe channels from the multi-probe channel table. The probe numbers corresponding to the selected multi-probe channels are non-adjacent according to the spatial arrangement order of the multi-probe array 120. Subsequently, the test controller 150 queries the path markers corresponding to the selected multi-probe channels under the same vehicle attitude angle, the same operating frequency, and the same calibration receiving point number. When two selected multi-probe channels correspond to the same calibration receiving point number and are both boundary occlusion paths, or both are in-cabin incident paths, the test controller 150 removes one of the multi-probe channels from the current calibration channel group and assigns the removed multi-probe channel to the next calibration channel group. This processing method avoids both spatial coupling caused by simultaneous calibration of adjacent anechoic chamber probes within the same calibration channel group and response aliasing of closely spaced occlusion paths at the same calibration receiving point.

[0119] In one implementation, the test controller 150 generates orthogonal calibration sequences for each multi-probe channel within the same calibrated channel group. The orthogonal calibration sequence includes a channel identification segment and an occlusion verification segment. The channel identification segment is generated based on the probe number, and is used to identify different multi-probe channels in the no-load reference response and the occupied calibration response. The occlusion verification segment is generated jointly based on the corresponding path marker and the corresponding probe number in the vehicle occlusion relationship table, under the same vehicle attitude angle and the same calibration receiving point number; the operating frequency is used to define the calibration task and response acquisition conditions corresponding to this occlusion verification segment.

[0120] Orthogonal calibration sequences can be pseudo-random codes, Walsh codes, constant envelope zero autocorrelation sequences, cyclic shift sequences, or other sequence forms suitable for multi-channel separation. To ensure that the multi-probe channels within the same calibration channel group can be separated, cross-correlation detection can be performed on any two orthogonal calibration sequences. The cross-correlation value can be determined according to equation (2):

[0121]

[0122] In the formula, This represents the cross-correlation value between two orthogonal calibration sequences; Indicates the sequence sampling number; Indicates the sequence length; Indicates the first orthogonal calibration sequence at the sequence sampling number The value at; Indicates the second orthogonal calibration sequence at the sequence sampling number The value at that location. When When the cross-correlation threshold is not greater than a preset threshold, the test controller 150 determines that the two orthogonal calibration sequences meet the separation requirements within the same group of channels to be calibrated. The preset cross-correlation threshold can be determined based on the receiver dynamic range, calibration sequence length, and repeated measurement results. Within the same group of channels to be calibrated, any two multi-probe channels have different channel identification segments and different occlusion verification segments.

[0123] In this embodiment, the test controller 150 first places the unloaded calibration component 200 in the vehicle bearing position 110, and loads an orthogonal calibration sequence onto the calibration channel group under preset vehicle attitude angle, preset operating frequency, preset polarization branch, and preset calibration channel group, and collects the unloaded reference response. The unloaded reference response is used to characterize the amplitude and phase responses of the multi-probe test system itself and the corresponding calibration receiving point of the unloaded calibration component 200 when the vehicle occupant 300 is not introduced. The test controller 150 can determine the channel amplitude and phase correction amount from the unloaded reference response. The channel amplitude and phase correction amount is used to represent the amplitude and phase correction requirements of the multi-probe channel itself under the corresponding operating frequency, polarization branch, probe number, and calibration receiving point partition.

[0124] Subsequently, the test controller 150 replaces the unloaded calibration component 200 with a vehicle occupant 300, maintaining the same vehicle attitude angle, operating frequency, polarization branch, and calibrated channel group, and acquires the occupant calibration response. The occupant calibration response characterizes the multi-probe channel response introduced by the vehicle occupant 300, including the amplitude and phase errors of the multi-probe test system's own channels, as well as the occlusion, boundary scattering, and in-cabin incident amplitude and phase shift introduced by the vehicle structure. The test controller 150 performs amplitude and phase registration between the occupant calibration response at the corresponding numbered calibration receiving point and the unloaded reference response, generating the vehicle occlusion amplitude and phase shift. The vehicle occlusion amplitude and phase shift represents the amplitude and phase shift introduced by the vehicle occupant 300 relative to the unloaded calibration component 200. If the same-source drift correction is not triggered, the acquired unloaded reference response and occupant calibration response can be used for calculation; if the same-source drift correction is triggered, the unloaded reference response and occupant calibration response after same-source drift correction are used for calculation.

[0125] In one calculation example, a multi-probe channel with a vehicle attitude angle of 60°, an operating frequency of 3.5 GHz, a vertical polarization branch, probe number 12, and a calibration receiver point numbered P03 are selected for illustration. This calibration receiver point is located in the vehicle boundary area. The no-load amplitude response in the no-load reference response is -47.20 dBm, the preset reference amplitude response is -45.00 dBm, and the occupied amplitude response in the occupied calibration response is -50.10 dBm. The channel amplitude correction, vehicle occlusion amplitude offset, and amplitude correction are determined as follows:

[0126]

[0127] In the formula, This indicates the channel amplitude correction amount, in dB. This indicates the preset reference amplitude response, in dBm. This represents the no-load amplitude response, in dBm. Substituting the values ​​above, we get:

[0128]

[0129] The vehicle occlusion offset is determined as follows:

[0130]

[0131] In the formula, This indicates the offset of the vehicle's occlusion range, in dB. This indicates the positional amplitude response, in dBm. This represents the no-load amplitude response, in dBm. Substituting the values ​​above, we get:

[0132]

[0133] The amplitude correction amount is determined as follows:

[0134]

[0135] In the formula, This indicates the amplitude correction amount, in dB. This indicates the channel amplitude correction amount, in dB. This represents the offset of the vehicle's occlusion range, in dB. Substituting the values ​​above, we get:

[0136]

[0137] Therefore, for the multi-probe channel with probe number 12, under the conditions of vehicle attitude angle of 60°, operating frequency of 3.5GHz, vertical polarization branch and calibration receiver number P03, amplitude and phase adjustment branch 140 can be loaded with an amplitude correction of 5.10dB.

[0138] Regarding phase correction, in the same calculation example, the unloaded phase response is 17.0°, the preset reference phase response is 0°, and the occupied phase response is -12.0°. Since the phase difference may cross the boundary between -180° and 180°, this embodiment normalizes the phase difference. The phase normalization calculation formula is as follows:

[0139]

[0140] In the formula, This represents the normalized phase difference, in degrees. This represents the phase difference before normalization, in degrees. This indicates the modulo operation.

[0141] The channel phase correction amount is determined as follows:

[0142]

[0143] In the formula, This indicates the channel phase correction amount, in degrees. This indicates the preset reference phase response, in degrees. This represents the no-load phase response, measured in degrees. Substituting the values ​​above, we get:

[0144]

[0145] The vehicle occlusion phase offset is determined as follows:

[0146]

[0147] In the formula, This indicates the vehicle's phase offset, expressed in degrees. This indicates the positional phase response, in degrees. This represents the no-load phase response, measured in degrees. Substituting the values ​​above, we get:

[0148]

[0149] The phase correction amount is determined as follows:

[0150]

[0151] In the formula, This indicates the phase correction amount, in degrees. This indicates the channel phase correction amount, in degrees. This represents the vehicle's phase offset, measured in degrees. Substituting the values ​​above, we get:

[0152]

[0153] Therefore, for the multi-probe channel with probe number 12, under the conditions of vehicle attitude angle of 60°, operating frequency of 3.5GHz, vertical polarization branch, and calibration receiver number P03, the amplitude and phase adjustment branch 140 can be loaded with a phase correction of 12.0°.

[0154] During response separation, the test controller 150 performs channel matching on the no-load reference response based on the channel identification segment to obtain the no-load initial amplitude and phase response corresponding to each multi-probe channel; it also performs channel matching on the occupancy calibration response based on the channel identification segment to obtain the occupancy initial amplitude and phase response corresponding to each multi-probe channel. Then, the test controller 150 performs path marker matching on the occupancy initial amplitude and phase responses under the same vehicle attitude angle, the same operating frequency, the same probe number, and the same calibration receiver point number, based on the occupancy verification segment. When the path marker matching result matches the corresponding path marker in the vehicle occupancy relationship table, the no-load initial amplitude and phase response is used as the no-load channel amplitude and phase response of the corresponding multi-probe channel, and the occupancy initial amplitude and phase response is used as the occupancy channel amplitude and phase response of the corresponding multi-probe channel. When the path marker matching result does not match the corresponding path marker in the vehicle occupancy relationship table, the corresponding multi-probe channel is added to the recalibrated channel set. The recalibrated channel set is used to record multi-probe channels whose path marker matching results do not match the vehicle occupancy relationship table.

[0155] In one implementation, after generating the channel group to be calibrated, the test controller 150 further establishes a calibration task queue. The calibration task queue divides the channel group to be calibrated into unobstructed calibration tasks, boundary occlusion calibration tasks, and in-cabin incidence calibration tasks according to path markers. Unobstructed calibration tasks correspond to unobstructed paths, boundary occlusion calibration tasks correspond to boundary occlusion paths, and in-cabin incidence calibration tasks correspond to in-cabin incidence paths. Each calibration task in the calibration task queue records the vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiver number. The calibration task queue can be executed in ascending order of vehicle attitude angle, in batches according to path marker categories, or in groups according to operating frequency.

[0156] When performing boundary occlusion calibration and cabin incidence calibration tasks, the test controller 150 can acquire a first occupancy calibration response at the current vehicle attitude angle and a second occupancy calibration response at a vehicle attitude angle adjacent to the current vehicle attitude angle in the calibration task queue. Subsequently, the test controller 150 determines the path markers corresponding to the first and second occupancy calibration responses, respectively. When the two path markers are inconsistent, the attitude angle interval between the current vehicle attitude angle and the adjacent vehicle attitude angle is marked as a supplementary calibration interval. The supplementary calibration interval is used to indicate that the vehicle occlusion state has changed within this attitude angle interval, and it is not appropriate to directly use the amplitude and phase correction amounts at adjacent vehicle attitude angles for ordinary interpolation.

[0157] In one implementation, when acquiring the no-load reference response and the occupancy calibration response, the test controller 150 also activates a reference monitoring channel. The main radiation direction of the anechoic chamber probe corresponding to the reference monitoring channel does not point towards the vehicle bearing position 110, so that the monitoring response of the reference monitoring channel does not directly include the obstruction, boundary scattering, and phase shift of the incident amplitude introduced by the vehicle occupant 300. The reference monitoring channel and the channel group to be calibrated are synchronously loaded with a reference calibration sequence. The test controller 150 performs homogeneous drift correction on the no-load reference response and the occupancy calibration response based on the monitoring response of the reference monitoring channel during the acquisition of the no-load reference response and the monitoring response during the acquisition of the occupancy calibration response.

[0158] Specifically, the test controller 150 acquires the first monitoring response of the reference monitoring channel during the acquisition of the no-load reference response and the second monitoring response of the reference monitoring channel during the acquisition of the position calibration response. The test controller 150 determines the drift response based on the first and second monitoring responses. When the drift response meets the drift correction condition determined by repeated measurement results, the no-load reference response and the position calibration response are corrected based on the drift response. The drift correction condition can be determined by multiple repeated measurement results under the same vehicle attitude angle, the same operating frequency, and the same polarization branch. For example, the drift correction condition can be determined based on the standard deviation of the repeated measurement results, the receiver amplitude resolution, the receiver phase resolution, or the stability threshold obtained from the test system calibration.

[0159] In one calculation example, the reference monitoring channel has a first monitoring amplitude response of -60.20 dBm during the acquisition of the no-load reference response and a second monitoring amplitude response of -59.90 dBm during the acquisition of the occupancy calibration response. The amplitude drift response is then determined as follows:

[0160]

[0161] In the formula, This represents the amplitude drift response, measured in dB. This indicates the first monitoring amplitude response, in dBm. This represents the second monitoring amplitude response, measured in dBm. Substituting the values ​​above, we get:

[0162] If the amplitude drift correction condition determined by repeated measurements is an amplitude drift response greater than 0.20 dB, then the amplitude drift response satisfies the drift correction condition. In this case, the positional amplitude response can be corrected as follows:

[0163]

[0164] In the formula, This represents the positional amplitude response after drift correction, in dBm. This indicates the positional amplitude response before correction, in dBm. This represents the amplitude drift response, in dB. If the uncorrected positional amplitude response is -50.10 dBm, then:

[0165]

[0166] The reference monitoring channel has a first monitoring phase response of 4.0° during the acquisition of the no-load reference response and a second monitoring phase response of 5.5° during the acquisition of the occupancy calibration response. The phase drift response is then determined as follows:

[0167]

[0168] In the formula, This represents the phase drift response, measured in degrees. This indicates the first monitored phase response, expressed in degrees. This represents the second monitored phase response, measured in degrees. Substituting the values ​​above, we get:

[0169]

[0170] If the phase drift correction condition determined by repeated measurements is a phase drift response greater than 1.0°, then the phase drift response satisfies the drift correction condition. In this case, the occupied phase response can be corrected as follows:

[0171]

[0172] In the formula, This represents the occupied phase response after drift correction, in degrees; This indicates the uncorrected positional phase response, in degrees. This represents the phase drift response, in degrees. If the uncorrected occupied phase response is -12.0°, then:

[0173]

[0174] After performing source drift correction, the test controller 150 performs amplitude and phase registration between the positional calibration response after source drift correction and the no-load reference response after source drift correction. When the amplitude registration result or phase registration result does not meet the consistency conditions determined by the repeated measurement results of the corresponding calibration receiving point, the corresponding probe number, operating frequency, polarization branch, vehicle attitude angle, and calibration receiving point number are written into the local recalibration list. The local recalibration list is used to record calibration tasks where the amplitude registration result or phase registration result does not meet the consistency conditions. The test controller 150 can execute the recalibration operations corresponding to the set of channels to be recalibrated and the local recalibration list separately, or it can merge the two to generate a unified recalibration task. The test controller 150 determines the corresponding multi-probe channel based on the probe number, operating frequency, and polarization branch in the local recalibration list, and re-acquires the corresponding positional calibration response under the vehicle attitude angle and calibration receiving point number in the local recalibration list. The consistency conditions can be determined by the amplitude stability interval and phase stability interval of the same calibration receiving point in repeated acquisitions, or by the repeatability index obtained by the test system in advance.

[0175] like Figure 4 As shown, the test controller 150 generates amplitude and phase correction values ​​based on the channel amplitude and phase correction values ​​and the vehicle occlusion amplitude and phase offset values, and forms an amplitude and phase calibration table based on vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiver point partition index. The amplitude and phase calibration table includes an idle channel correction sub-table, a vehicle occlusion offset sub-table, a receiver point partition sub-table, and a recalibration status sub-table. The idle channel correction sub-table stores the channel amplitude and phase correction values. The vehicle occlusion offset sub-table stores the vehicle occlusion amplitude and phase offset values. The receiver point partition sub-table stores the correspondence between calibration receiver point numbers and calibration receiver point partitions. The recalibration status sub-table includes probe number field, operating frequency field, polarization branch field, vehicle attitude angle field, calibration receiver point number field, local recalibration status field, and isolated channel status field. Through the above sub-table structure, the test controller 150 can separately save the system channel amplitude and phase error, vehicle structure amplitude and phase offset, calibration receiver point partition, and recalibration status, and combine and call them during large-scale MIMO vehicle OTA testing.

[0176] In one implementation, when the actual vehicle attitude angle of the vehicle under test does not match the vehicle attitude angle index in the amplitude-phase calibration table, the test controller 150 determines the path marker corresponding to the actual vehicle attitude angle based on the vehicle occlusion relationship table for the probe number and calibration receiving point number of the amplitude-phase correction value to be read, and selects two vehicle attitude angle indices adjacent to the actual vehicle attitude angle. Subsequently, the test controller 150 determines the path markers corresponding to the two adjacent vehicle attitude angle indices for the probe number and calibration receiving point number of the amplitude-phase correction value to be read. When the path marker corresponding to the actual vehicle attitude angle is consistent with the path markers corresponding to the two adjacent vehicle attitude angle indices, the amplitude-phase correction value corresponding to the actual vehicle attitude angle is generated based on the amplitude-phase correction value under the two adjacent vehicle attitude angle indices. When the path marker corresponding to the actual vehicle attitude angle is inconsistent with the path marker corresponding to any adjacent vehicle attitude angle index, the actual vehicle attitude angle is written into the set of attitude angles to be supplemented for calibration. This processing method ensures that the determination of the calibration value when the actual vehicle attitude angle does not match depends not only on the proximity of the attitude angle values, but also on the consistency of the propagation path markers.

[0177] In one calculation example, the actual vehicle attitude angle is 75°, and the indices of two adjacent vehicle attitude angles in the amplitude-phase calibration table are 60° and 90°, respectively. For the multi-probe channel with probe number 12 and the calibration receiver point with calibration receiver point number P03, the path markings corresponding to 75°, 60°, and 90° in the vehicle occlusion relationship table are all marked as boundary occlusion paths. Since the path markings corresponding to the three vehicle attitude angles are consistent, the amplitude-phase correction amount corresponding to 75° can be generated based on the amplitude-phase correction amounts at 60° and 90°. If the amplitude correction amount corresponding to 60° is 5.10dB and the amplitude correction amount corresponding to 90° is 5.70dB, then the amplitude correction amount corresponding to 75° can be determined as follows:

[0178]

[0179] In the formula, This represents the amplitude correction amount corresponding to a 75° vehicle attitude angle, in dB. This represents the amplitude correction amount corresponding to a 60° vehicle attitude angle, in dB. This represents the amplitude correction amount corresponding to a 90° vehicle attitude angle, in dB. Substituting the values ​​above, we get:

[0180]

[0181] If the phase correction value corresponding to 60° is 12.0° and the phase correction value corresponding to 90° is 15.0°, then the phase correction value corresponding to 75° can be determined as follows:

[0182]

[0183] In the formula, This represents the phase correction amount corresponding to a 75° vehicle attitude angle, in degrees. This represents the phase correction amount corresponding to a 60° vehicle attitude angle, in degrees. This represents the phase correction amount corresponding to a 90° vehicle attitude angle, in degrees. Substituting the values ​​above, we get:

[0184]

[0185] If the path corresponding to the actual vehicle attitude angle of 75° is marked as a boundary occlusion path, and the path corresponding to the adjacent vehicle attitude angle of 90° is marked as an in-cabin incident path, then the test controller 150 will not perform the above interpolation process, but will write the actual vehicle attitude angle of 75° into the set of attitude angles to be supplemented for calibration, so that the supplementary calibration can be re-executed later.

[0186] Before performing large-scale MIMO vehicle OTA testing, the test controller 150 loads the amplitude and phase calibration table and reads the corresponding amplitude and phase correction values ​​based on the vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiver point partition. The test controller 150 reads the corresponding amplitude and phase correction values ​​from the idle channel correction sub-table and the vehicle occlusion offset sub-table based on the vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiver point partition, and sends the read amplitude and phase correction values ​​to the amplitude and phase adjustment branch 140. The amplitude and phase adjustment branch 140 performs amplitude and phase correction on the corresponding multi-probe channels based on the received amplitude and phase correction values. When the isolation channel status field in the recalibration status sub-table is recorded as isolated, the test controller 150 determines the corresponding multi-probe channel based on the probe number field, operating frequency field, and polarization branch field in the recalibration status sub-table and masks the corresponding multi-probe channel. The shielding method can be to close the corresponding channel simulator port, disable the output of the corresponding amplitude and phase adjustment branch 140, remove the corresponding anechoic chamber probe from the current large-scale MIMO vehicle OTA test task, or switch the multi-probe channel to a backup multi-probe channel.

[0187] To illustrate the technical effects achieved in this embodiment, a comparative test was conducted between the existing scheme that only performs path loss calibration on a multi-probe system and the calibration method of this embodiment. The test object was a multi-probe array 120 containing 64 anechoic chamber probes. The test frequency band covered multiple operating frequencies in commonly used vehicle communication frequency bands. The vehicle attitude angles were set at equal angular intervals, and the calibration receiving points were distributed in the vehicle antenna mounting area, the vehicle body boundary area, and the cabin scattering area. The existing scheme only uses multi-probe channel path loss calibration data under no-load conditions, does not establish a vehicle occupancy relationship table, and does not distinguish between vehicle occupancy amplitude and phase offsets. This embodiment collects the no-load reference response and the occupied calibration response according to the above process and generates an amplitude and phase calibration table.

[0188] The amplitude residual and the phase residual can be determined according to equations (16) and (17), respectively:

[0189]

[0190] In the formula, This represents the amplitude residual, in dB. This represents the measured amplitude response after calibration, in dBm. This represents the target amplitude response, measured in dBm.

[0191]

[0192] In the formula, This represents the phase residual, expressed in degrees. This represents the measured phase response after calibration, in degrees. The target phase response is expressed in degrees. Test results are shown in Table 1. Figure 5 and Figure 6 .

[0193] Table 1 Comparison of test results for different calibration methods

[0194] 0° 1.62 0.44 13.6 3.9 30° 1.88 0.49 16.8 4.8 60° 2.21 0.56 20.9 5.9 90° 2.58 0.63 25.7 7.1 120° 2.36 0.59 23.4 6.6 150° 2.05 0.52 19.2 5.4 180° 1.74 0.47 15.1 4.4

[0195] Figure 5 The comparison curves of amplitude residuals at different vehicle attitude angles are shown. Figure 5 In the diagram, curve 1 represents the existing scheme that only performs path loss calibration for multi-probe systems, while curve 2 represents the anechoic chamber multi-probe amplitude and phase calibration method of this embodiment. Figure 5 It can be seen that the amplitude residual of the existing solution increases with the change of the occlusion state when the vehicle attitude angle changes. This embodiment corrects the amplitude correction amount by using the no-load reference response, the occupancy calibration response and the vehicle occlusion amplitude and phase offset, so that the amplitude residual under different vehicle attitude angles is kept in a low range. Figure 6 The comparison curves of phase residuals under different vehicle attitude angles are shown. Figure 6In the diagram, curve 1 represents the existing scheme that only performs path loss calibration for multi-probe systems, while curve 2 represents the anechoic chamber multi-probe amplitude and phase calibration method of this embodiment. Figure 6 It can be seen that the existing solution increases the phase residual near the attitude angle where the vehicle body boundary occlusion and the incident radiation inside the cabin have a strong influence; this embodiment reduces the problem of mismatch between the phase correction amount and the actual propagation path state by using path marking, occlusion verification segment and same source drift correction.

[0196] Table 2 Comparison of comprehensive test indicators for different calibration methods

[0197] Average amplitude residual in vehicle antenna mounting area (unit: dB) 1.82 0.46 Average amplitude residual in the vehicle body boundary area (unit: dB) 2.37 0.61 Average amplitude residual in the in-cabin scattering region (unit: dB) 2.91 0.74 Average phase residual in the vehicle antenna mounting area (unit: °) 14.8 4.2 Average phase residual in the vehicle body boundary region (unit: °) 21.5 6.8 Average phase residual in the in-cabin scattering region (unit: °) 27.6 8.1 Number of incorrect calls when attitude angles are not matched (unit: times) 17 3 Number of channels requiring full re-certification (unit: channels) 64 9 Accuracy of identifying occlusion state change range 68.5% 93.4%

[0198] In Table 2, the number of erroneous calls due to attitude angle misses can be statistically analyzed based on 100 sets of attitude angle miss test tasks, counting the number of amplitude and phase correction calls that are mismatched due to inconsistent path markings. The accuracy of identifying occlusion state change intervals can be compared with the results of manual calibration or 3D model path analysis, counting the proportion of the identification results of the intervals to be supplemented for calibration that are consistent with the reference results.

[0199] From Table 1, Table 2, Figure 5 and Figure 6 It can be seen that after the introduction of the 300-inch vehicle occupant, the existing scheme of only calibrating the path loss of the multi-probe system is difficult to reflect the influence of the vehicle structure on the propagation path in different spatial areas, especially in the vehicle boundary area and the cabin scattering area where the amplitude and phase residuals are large. This embodiment, through dual-state acquisition of the no-load reference response and the occupant calibration response, path marking of the vehicle occupancy relationship table, generation of non-adjacent calibration channel groups, occupancy verification segments, and vehicle occupancy amplitude and phase offset, can distinguish the channel amplitude and phase errors of the multi-probe test system itself from the amplitude and phase offset introduced by the vehicle structure, and establish a correspondence between the amplitude and phase correction amount and the vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiver partition. Compared with the existing scheme that only performs path loss calibration, this embodiment reduces the amplitude and phase residuals in the vehicle antenna installation area, vehicle boundary area, and cabin scattering area, and can reduce the number of erroneous calls when the attitude angle is not hit and the number of channels requiring full recalibration.

[0200] In this embodiment, the vehicle occlusion table, the channel group to be calibrated, the orthogonal calibration sequence, the calibration task queue, the same-source drift correction, the local recalibration list, the channel set to be recalibrated, the amplitude and phase calibration table, and the isolated channel status are not independent ordinary data processing processes, but rather coordinated around the same technical goal in the whole vehicle OTA anechoic chamber multi-probe calibration. The vehicle occlusion table is used to establish a correspondence between the whole vehicle structure and the propagation path from the anechoic chamber probe to the calibration receiving point; the channel group to be calibrated is used to organize the multi-probe channels under path marking constraints; the orthogonal calibration sequence is used to separate the multi-probe channel responses and verify the path markings; the same-source drift correction is used to reduce the impact of system drift on amplitude registration and phase registration during dual-state acquisition; the channel set to be recalibrated is used to record multi-probe channels whose path marking matching results are inconsistent with the vehicle occlusion table; the local recalibration list is used to reacquire the placeholder calibration response only for calibration tasks where the amplitude registration result or phase registration result does not meet the consistency condition; the amplitude and phase calibration table is used to load the corresponding amplitude and phase correction amount to the amplitude and phase adjustment branch 140 before the execution of large-scale MIMO whole vehicle OTA test. This leads to a processing flow suitable for amplitude and phase calibration of multiple probes in an anechoic chamber during over-the-air (OTA) testing of complete vehicles.

[0201] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for anechoic chamber multi-probe amplitude and phase calibration for vehicle OTA testing, characterized in that, include: The darkroom is equipped with a vehicle bearing position, a multi-probe array, a channel simulator, an amplitude and phase adjustment branch, an unloaded calibration component, a vehicle occupant, and a test controller for large-scale MIMO vehicle OTA testing. The multi-probe array includes multiple darkroom probes, each of which is assigned a probe number. The vehicle occupant is the vehicle under test or the equivalent scattering body of the whole vehicle. Configure the operating frequency and polarization branch, and obtain the vehicle attitude angle of the vehicle occupier; The unloaded calibration component and the vehicle occupant are provided with corresponding numbered calibration receiving points. Each calibration receiving point has a calibration receiving point number and a calibration receiving point partition. The calibration receiving point partition includes a vehicle antenna installation area, a vehicle body boundary area, and an in-cabin scattering area. Establish a multi-probe channel table, wherein each multi-probe channel in the multi-probe channel table corresponds to an anechoic chamber probe, a channel simulator port, an amplitude and phase adjustment branch, a polarization branch, and at least one operating frequency point; Establish a vehicle occlusion relationship table. The table entries include vehicle attitude angle, probe number, calibration receiver point number, and path marker. The path marker includes unobstructed path, boundary occlusion path, and in-cabin incident path. Generate non-adjacent channels to be calibrated based on the vehicle occlusion relationship table; The unloaded calibration component is placed in the vehicle bearing position, an orthogonal calibration sequence is loaded onto the channel group to be calibrated, and the unloaded reference response is collected. Replace the unloaded calibration component with the vehicle occupant, and collect the occupant calibration response under the same vehicle attitude angle, the same operating frequency, the same polarization branch, and the same group of channels to be calibrated. The channel amplitude and phase correction amount is determined based on the no-load reference response and the preset reference response. The occupancy calibration response under the corresponding numbered calibration receiving point is amplitude registered and phase registered with the no-load reference response to generate the vehicle occupancy amplitude and phase offset. Amplitude and phase correction values ​​are generated based on the channel amplitude and phase correction values ​​and the vehicle occlusion amplitude and phase offset values, and an amplitude and phase calibration table is formed according to the vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiver point partition index.

2. The anechoic chamber multi-probe amplitude and phase calibration method according to claim 1, characterized in that, Establishing the vehicle occlusion relationship table includes: Obtain the outer contour region, window region, and metal boundary region of the vehicle occupier; Determine the connection path between each anechoic chamber probe and each calibration receiving point in the multi-probe array; The connection path is matched with the outer contour area, the window area, and the metal boundary area. Based on the region matching results, the connecting path is marked as an unobstructed path, a boundary obstructed path, or an in-cabin incident path, and the corresponding path marking is saved with the vehicle attitude angle, probe number, and calibration receiver point number.

3. The anechoic chamber multi-probe amplitude and phase calibration method according to claim 2, characterized in that, Determining the calibration receiver zone includes: The vehicle antenna installation area is determined based on the vehicle communication antenna installation coordinates of the vehicle occupant. The vehicle body boundary area is determined based on the outer contour area, the window area, and the metal boundary area; The in-cabin scattering zone is determined based on the installation coordinates of the cockpit communication module of the vehicle occupant and the coordinates of the in-cabin reflective components. Establish a one-to-one mapping relationship between each calibration receiving point number and its corresponding calibration receiving point partition.

4. The anechoic chamber multi-probe amplitude and phase calibration method according to claim 1, characterized in that, The unloaded calibration component and the vehicle occupant are provided with corresponding numbered calibration receiving points, including: A first type of calibration receiving point, a second type of calibration receiving point, and a third type of calibration receiving point are provided on the unloaded calibration component; The first type of calibration receiving point corresponds to the vehicle antenna mounting area, the second type of calibration receiving point corresponds to the vehicle body boundary area, and the third type of calibration receiving point corresponds to the cabin scattering area. On the vehicle occupant, calibration receiving points are set up, each corresponding to one of the first type of calibration receiving point, the second type of calibration receiving point, and the third type of calibration receiving point; Establish a coordinate registration relationship between two calibration receiving points with the same number.

5. The anechoic chamber multi-probe amplitude and phase calibration method according to claim 1, characterized in that, The generation of non-adjacent channels to be calibrated based on the vehicle occlusion relationship table includes: Select a multi-probe channel from the multi-probe channel table, wherein the probe numbers corresponding to the multi-probe channels are not adjacent to each other according to the spatial arrangement order of the multi-probe array; Query the path markers corresponding to the selected multi-probe channels under the same vehicle attitude angle, the same operating frequency, and the same calibration receiver point number; When two selected multi-probe channels correspond to the same calibration receiving point number and are both boundary obstruction paths or both are in-cabin incident paths, one of the multi-probe channels will be removed from the current calibration channel group. The removed multi-probe channels are incorporated into the next group of channels to be calibrated.

6. The anechoic chamber multi-probe amplitude and phase calibration method according to claim 5, characterized in that, Loading the orthogonal calibration sequence into the group of channels to be calibrated includes: Generate orthogonal calibration sequences for each multi-probe channel within the same group of channels to be calibrated; The orthogonal calibration sequence includes a channel identification segment and an occlusion verification segment; The channel identification segment is generated based on the probe number; Under the same vehicle attitude angle, the same operating frequency, and the same calibration receiver number, the occlusion verification segment is generated together with the corresponding path marker and the corresponding probe number in the vehicle occlusion relationship table. Within the same group of channels to be calibrated, any two multi-probe channels have different channel identification segments and different occlusion verification segments.

7. The anechoic chamber multi-probe amplitude and phase calibration method according to claim 6, characterized in that, Separating the channel amplitude and phase responses of each multi-probe channel from the unloaded reference response and the occupancy calibration response includes: Based on the channel identification segment, channel matching is performed on the no-load reference response to obtain the no-load initial amplitude and phase response corresponding to each multi-probe channel; Based on the channel identification segment, channel matching is performed on the occupancy calibration response to obtain the occupancy initial amplitude and phase response corresponding to each multi-probe channel; Based on the occupancy verification segment, path marking matching is performed on the occupancy initial amplitude and phase responses under the same vehicle attitude angle, the same operating frequency, the same probe number, and the same calibration receiver number; When the path marker matching result matches the path marker in the vehicle occlusion relationship table, the unloaded initial amplitude-phase response is used as the unloaded channel amplitude-phase response of the corresponding multi-probe channel, and the occupied initial amplitude-phase response is used as the occupied channel amplitude-phase response of the corresponding multi-probe channel. When the path marker matching result is inconsistent with the path marker corresponding to the vehicle occlusion relationship table, the corresponding multi-probe channel will be included in the channel set to be recalibrated.

8. The anechoic chamber multi-probe amplitude and phase calibration method according to claim 5, characterized in that, After generating the group of channels to be calibrated, the process also includes establishing a calibration task queue; The calibration task queue divides the channel group to be calibrated into unobstructed calibration tasks, boundary obstructed calibration tasks, and in-cabin incident calibration tasks according to the path marking. The unobstructed calibration task corresponds to the unobstructed path; The boundary occlusion calibration task corresponds to the boundary occlusion path; The in-cabin incident calibration task corresponds to the in-cabin incident path; Each calibration task in the calibration task queue records the vehicle attitude angle, operating frequency, polarization branch, probe number, and calibration receiver number.

9. The anechoic chamber multi-probe amplitude and phase calibration method according to claim 8, characterized in that, When performing the boundary occlusion calibration task and the in-cabin incidence calibration task, the method further includes: Acquire the first occupancy calibration response at the current vehicle attitude angle; A second occupancy calibration response is acquired at the vehicle attitude angle adjacent to the current vehicle attitude angle in the calibration task queue; Determine the path markers corresponding to the first placeholder calibration response and the second placeholder calibration response respectively; When the two path markings are inconsistent, the attitude angle interval between the current vehicle attitude angle and the vehicle attitude angle adjacent to the current vehicle attitude angle is marked as the interval to be supplemented for calibration.

10. The anechoic chamber multi-probe amplitude and phase calibration method according to claim 1, characterized in that, When collecting the no-load reference response and the occupancy calibration response, the reference monitoring channel is also enabled. The main radiation direction of the anechoic chamber probe corresponding to the reference monitoring channel does not point to the vehicle bearing position; The reference monitoring channel and the group of channels to be calibrated are synchronously loaded with a reference calibration sequence; Based on the monitoring response of the reference monitoring channel during the acquisition of the no-load reference response and the acquisition of the occupancy calibration response, the no-load reference response and the occupancy calibration response are subjected to homogeneous drift correction.

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