Radar transceiver test method and system

Abstract

The present disclosure relates to a method for controlling a function of a vehicle radar transceiver (3), wherein the method comprises transmitting (S100) radar signals (5) and collecting and storing (S300) target data comprising a received detected signal level obtained from a reflected radar signal (6) reflected by at least one target object (7) during a measurement angular interval (21). The method further comprises determining (S400) that the radar transceiver (3) is functioning properly when at least one of the following conditions is met: - the detected signal level exceeds a minimum signal level (12) during an angular interval (Θ i ) comprised in the measurement angular interval (21); and - a detected signal level variation for a certain angular variation is below a certain limit during an angular interval (Θ i ) comprised in the measurement angular interval (21).

Description

SUMMARY

[0001] The present disclosure relates to a method and a measuring system for testing radar transceivers suitable for automotive applications, in particular for testing radar transceivers mounted inside or behind bumpers.

[0002] A radar transceiver is generally a device arranged for transmitting and receiving radar signals in a dedicated radar frequency band. Radar transceivers are commonly used in vehicles for monitoring the environment around the vehicle. Automatic cruise control (ACC) functions, emergency brake (EB) functions, advanced driver assistance systems (ADAS) and autonomous driving (AD) are some examples of applications where radar data represent an important source of information on the basis of which the vehicle control is based.

[0003] Radar transceivers are located in various positions, some of them behind the vehicle bumper which acts as a secondary radar radome. For these cases, it can be necessary to be able to evaluate potential blockages. Typical blockage cases are when the bumper is blocked by objects such as snow or other deposits when the vehicle is parked, and when the bumper in front of the radar transceiver needs to be repaired and must be repainted.

[0004] In the latter case, it is difficult to control the paint properties of the repainted bumper. The paint must match the rest of the paint, so it is often necessary to mix various elements to achieve the same color. The properties of the new paint can differ from the properties of the original paint, and the way the painting is done will affect the radar transceiver original performance in terms of detection range and azimuth angle estimation accuracy. Excess paint will cause the radar range to be reduced, sometimes in the form of a narrow notch caused by the reflected signal between the radar and the dashboard being canceled out.

[0005] Therefore, it is necessary to check whether and to what extent the new paint affects the range and azimuth angle estimation performance. However, it is not always possible to drive the vehicle at the repair shop.

[0006] There are also static methods, such as measuring the thickness using an ultrasonic probe. The problem with this method is that the performance depends not only on the thickness, but also on the material that is painted. Depending on the radar transceiver, it is not always possible to define pass / fail criteria.

[0007] Another example of a static method is to measure the radiated wave using a receiver device. This is relatively accurate, but requires a suitable device to be able to measure the RF signal. Such devices are expensive and cannot be deployed in all repair shops.

[0008] There is thus a need for further improvements, in particular of the radar transceiver properties of a bumper controlling whether and to what extent repainting has taken place. Such control should be possible to perform without moving the vehicle and by using low-cost equipment. Generally, there is a need for improvements of the testing of the radar transceiver function, in particular after a known change in the transceiver itself or its surroundings such as e.g. the mentioned repainting. SUMMARY

[0010] It is an object of the present disclosure to provide a method and a measurement system for controlling whether and to what extent radar transceiver properties have changed. This can be done after a known change in the transceiver itself or its surroundings such as e.g. after a bumper covering the radar transceiver has been repainted. Such control should be possible to perform without moving the vehicle and by using low-cost equipment.

[0011] This object is achieved by a method for controlling a function of a vehicle mounted radar transceiver. The method comprises transmitting radar signals and collecting and storing target data comprising received detected signal levels obtained from reflected radar signals reflected by at least one target object during a measurement angular interval. The method further comprises determining that the radar transceiver is functioning normally when at least one of the following conditions is fulfilled:

[0012] - the detected signal level exceeds a minimum signal level during an angular interval comprised in the measurement angular interval.

[0013] - a change in the detected signal level for a certain angular change is below a certain limit during an angular interval comprised in the measurement angular interval.

[0014] In this way, it is easy to check whether and to what extent radar transceiver properties have changed, in particular after a known change in the transceiver itself or its surroundings such as e.g. the mentioned repainting.

[0015] According to some aspects, the method comprises moving the target object along a measurement arc at a distance from the radar transceiver during the measurement angular interval.

[0016] This provides a coherent coverage of data from a plurality of angles within the measurement angular interval.

[0017] According to some aspects, a line is used to maintain the distance.

[0018] In this way, the distance is maintained in a simple and reliable way.

[0019] According to some aspects, the method comprises monitoring the azimuth of the target object over time as the target object moves around the measurement arc, and comparing the monitored azimuth with an expected azimuth trajectory.

[0020] In this way, it can be determined whether the radar transceiver is functioning properly in a simple and reliable manner.

[0021] According to some aspects, there are two or more target objects in one or more corresponding fixed positions.

[0022] If there are no movable target objects, this will result in a loss of information between the fixed targets, but without the need for moving target objects.

[0023] According to some aspects, a metal tube or a metal rod is used as a target object.

[0024] This means that a simple structure can be used as a target object.

[0025] According to some aspects, the target object is cylindrical and is arranged vertically on a wheeled carriage.

[0026] According to some aspects, the minimum signal level varies with the azimuth.

[0027] Also disclosed herein is a measurement system associated with the above-mentioned advantages.

[0028] Generally, unless otherwise defined, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field. All references to “one / that element, device, component, means, step or the like” are to be interpreted discursively as referring to at least one instance of whatever is being referenced. The steps of any method disclosed herein need not be performed in the exact order disclosed, unless explicitly stated. Additional features and advantages of the present disclosure will be apparent from the claims and following description. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. It is the following claims, not the preceding description, which define the scope of this disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0029] The present disclosure will now be described in more detail with reference to the accompanying drawings, in which:

[0030] Figure 1 A top view of a vehicle is schematically shown;

[0031] Figure 2 A first curve of detected amplitude versus azimuth is schematically shown;

[0032] Figure 3a second curve of detected amplitude versus azimuth angle is schematically shown; and

[0033] Figure 4 is a flow chart of the illustrated method. DETAILED DESCRIPTION

[0034] Aspects of the disclosure will now be described more fully in connection with the accompanying drawings. However, the various devices and methods disclosed herein can be implemented in many different forms and should not be construed as limited to the aspects set forth herein. Throughout this document, like reference numerals are used to refer to like elements in the accompanying drawings.

[0035] The terminology used herein is for the purpose of describing aspects of the disclosure only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0036] Figure 1 A top view of a vehicle 1 comprising a radar system 2, in turn comprising a radar transceiver 3 and a control unit 4, is shown. The radar transceiver 3 has a certain field of view (FOV) 9.

[0037] The radar transceiver 3 is adapted to transmit radar signals 5 and to receive reflected radar signals 6 that have been reflected by an object 7. The control unit 4 controls the radar transceiver 3, e.g. the transmission timing, the transmission frequency content and the actual transmission time waveform. The control unit 4 is further adapted to perform signal processing in order to extract target data related to the detected objects, e.g. for obtaining a 2D FFT of a range Doppler matrix in a previously well-known manner.

[0038] The radar transceiver 3 is located behind or inside a bumper 8 that serves as a radar antenna cover for the radar transceiver 3.

[0039] According to the disclosure, the control unit 4 is adapted to control the radar transceiver 3 to transmit radar signals 5 and to collect target data comprising received and detected amplitude levels obtained from reflected radar signals 6 that have been reflected by a target object 7 moving at a fixed radial distance L within the FOV 9. Thus, the target object 7, 7', 7" is moved along a measurement arc 10 between a start angle θ 起始 to a stop angle θ 停止 so that an azimuth measurement angle interval 21 is covered, e.g. -60° to +60°. The measurement angle interval 21 should be within the angular span 11 of the FOV. In Figure 1 the measurement angle interval 21 is shown to be below the angular span 11 of the FOV, but of course can be more or less equal to the angular span 11 of the FOV.

[0040] The collected target data is stored, at least in part, on the control unit 4 itself or on an external computer device 18, such as a laptop computer connected to the control unit 4 via a controller area network (CAN) bus 19.

[0041] Those skilled in the art will understand that, depending on some aspects, in addition to the detected amplitude level, or alternatively, the target data includes the signal-to-noise ratio (SNR) of the received reflected radar signal 6. Like any radio receiver, the radar system 2 can estimate its own noise floor, for example, in decibels. This will generally remain relatively constant over time and independent of the target azimuth angle θ. The SNR will be the ratio of the target amplitude to the noise level. The advantage of using SNR is that as the temperature of the radar transceiver 3 changes, the gain / signal amplification stage of the radar transceiver 3 changes, while the SNR remains more stable. Therefore, the SNR is less dependent on temperature and varies less between different radars. Throughout this disclosure, SNR and amplitude are used interchangeably.

[0042] The term signal level typically refers to amplitude level or SNR level. In the examples provided, amplitude level is discussed as signal level, but these examples certainly also apply to SNR level.

[0043] Figure 2 The target object 7 is shown from the starting angle θ. 起始 -60° to the stop angle θ 停止 The detected amplitude and azimuth angles are measured when the radar transceiver 3 passes through the angular interval between -60° and +60° multiple times. By analyzing the detected amplitude and azimuth angles, it can be determined whether the radar transceiver 3 is operating normally, and whether new bumper paint or other changes affect the operation of the radar transceiver 3. The analysis is performed based on several aspects executed at computer device 18.

[0044] Figure 2 and the following Figure 3 The amplitude level of the signal returned from the target, measured in dB by radar transceiver 3, is shown. Those skilled in the art will understand that this is also equivalent to the target's signal-to-noise ratio (SNR) as described above. This is in Figure 2 and Figure 3 The indicator shows that the Y-axis is labeled "Amplitude or SNR".

[0045] According to several factors, the selected target object 7 should ideally exhibit the same radar cross section (RCS) as it moves around the measuring arc 10, and the radar transceiver 3 should be able to distinguish the target object 7 by knowing the arc radius L a priori. Since not all radar transceivers are mounted at the same height on the vehicle, it is also beneficial to use target objects with a consistent RCS along the height range.

[0046] likeFigure 2 As shown, the detected amplitude level should exceed a specific minimum amplitude level 12, indicated by the dashed line, thus forming an amplitude mask. This means that the detected amplitude will not be affected by unacceptable attenuation. According to some aspects, the minimum amplitude level 12 is not constant over the azimuth angle θ, but rather a function that varies with the azimuth angle θ. Figure 2 and Figure 2 In the example, there is a minimum amplitude level of approximately -52 dB between azimuth angles of -50° and -40°, and another minimum amplitude level of -49 dB between azimuth angles of -40° and +50°. This is, of course, merely an illustration of one possibility for explaining the reasons for this disclosure.

[0047] Furthermore, according to some aspects, the detected amplitude level should follow a continuous trajectory, wherein the detected amplitude level change for a certain angle change should be within a certain limit, and according to some aspects, should be within a certain angular span.

[0048] If the above conditions are met, it is determined that the radar transceiver 3 is operating normally, and new bumper paint or other changes do not affect the operation of the radar transceiver 3 so that no action is required. According to some aspects, Figure 2 The curve in the figure illustrates this situation. Here, the detected amplitude level change for a certain angle increases to above +50° and below -50°, and according to some aspects, the detected amplitude level change for a certain angle only considers a certain angular interval θ. i Such as, for example, within the range of -50° to +50°. At this angular interval θ i In addition, the amplitude level drops relatively quickly, which is normal behavior.

[0049] for Figure 3 Another case is shown in the corresponding curve.

[0050] Assuming the movement of the target object 7 during the measurement is continuous and fairly constant, the measurement system 20 can check for any jumps in the angle estimation. If the target object 7 is observed over time, it is determined that the target object started at an angle θ. 起始 It begins and moves at a fairly constant speed to a stopping angle θ. 停止 The measurement system 20 should report this throughout this period. Depending on some aspects, linear curve fitting can be performed, and for example, a deviation of ±6° can be accepted.

[0051] According to some aspects, in this case the radar transceiver 3 is not determined to be functioning properly, since the detected amplitude level is below the minimum amplitude level 12 between approximately -49° and -42°. There are also several amplitude level notches or dips 13, 14, 15 which can correspond to irregular paint characteristics of a new paint layer. At these dips 13, 14, 15 the detected amplitude level does not follow a continuous trajectory and the detected amplitude level change for a certain angular change falls outside the predefined limits for a certain angular interval of detected amplitude jumps.

[0052] Thus, in the example of reference Figure 3 two different problems are provided, namely that the detected amplitude level is too low, and that the detected amplitude level jumps, such that the detected amplitude level dips 13, 14, 15.

[0053] According to some aspects, the target object 7 is constituted by a metal rod or a metal tube, in the following a metal tube is considered, which tube can be circular or rectangular. According to some aspects, the tube is mounted vertically and has a diameter of 20-40 mm. The vertical mounting of the radar transceiver is within a certain range, e.g. ±1°, ±2° or ±3°. According to some aspects, the tube is mounted to a wheeled carriage 16 connected to a wire 17, which wire 17 is attached to a vehicle or any other object, such that the radial distance L between the target object 7 and the radar transceiver 3 is maintained during movement of the carriage 16 and the target object 7.

[0054] The target object can be in the form of a corner reflector. A corner reflector will typically be mounted at approximately the same height as the radar antenna comprised in the radar transceiver 3, and does not need to be directed directly at the radar.

[0055] For a metal tube, the height is not important as long as the tube passes the FOV of the radar antenna.

[0056] A test arrangement designed in the above-described manner can be used in a normal workshop, and requires a small radius around the radar sensor, e.g. approximately 1 m.

[0057] The present disclosure is applicable to any suitable radar transceiver or radars transceivers comprised in the radar system 2. In Figure 1 only a rear corner radar transceiver 3 is shown, this is merely an example. Typically, there are several radar transceivers in such a radar system 2, and the present disclosure is applicable to some of these radar transceivers or to all of the radar transceivers in the radar system.

[0058] A non-limiting example of how the test is performed is provided below.

[0059] 1) The test operator sets up a wheeled carriage 16, such as a small carriage with a vertically extending aluminium tube of at least 1 meter length as the target object 7.

[0060] 2) Attach wire 17 to anchor point under bumper 8 with line length 22 constituting the radius set to approximately 100 cm.

[0061] 3) As an option, external computer device 18, such as a personal computer (PC), can read the internal temperature of radar transceiver 3 via CAN. This can be used to allow for temperature variations of radar transceiver 3, as a relatively cooler radar transceiver 3 will typically measure a higher SNR than a relatively warmer radar transceiver 3. This procedure can be built into control unit 4.

[0062] 4) As an option, PC 18 is adapted to configure radar transceiver 3 into a measurement mode with minimum / maximum radius, which allows control unit 4 to determine which radar detections correspond to target object 7, and which radar detections correspond to nearby buildings or test operator.

[0063] 5) Test operator stands behind target object 7 and moves carriage 16 around the FOV within e.g. 15 seconds.

[0064] 6) PC 18 records azimuth and detected amplitude level via CAN bus 19 and provides audible feedback to the engineer regarding e.g.:

[0065] - Target object 7 is detected within the FOV.

[0066] - Target object 7 reaches one azimuth extremum θ 起始 , θ 停止 . Test starts and proceeds well.

[0067] - End extremum is reached. Test is successfully completed.

[0068] 7) Detected amplitude level is cross-checked against amplitude mask 12 by PC 18. A pass or fail decision on the functionality of radar transceiver 3 is provided, and a hard copy of the test result is provided via a printer.

[0069] According to some aspects, assuming that target object 7 starts at -60° and ends at +60°, and that azimuth θ increases linearly over time and always maintains a positive gradient, it is also possible to monitor and check the azimuth estimate of target object 7 as reported by radar system 2.

[0070] The above is merely an example and should not be seen as limiting in any way. Cross-checking can of course also find the amplitude dips discussed above, either in addition or as an alternative method.

[0071] Reference Figure 4The present disclosure relates to a method for controlling the functioning of a vehicle radar transceiver 3. The method comprises transmitting S100 a radar signal 5 and collecting and storing S300 target data comprising received detected signal levels 21 obtained from reflected radar signals 6 reflected by at least one target object 7 during a measurement angular interval 21. The method further comprises determining S400 that the radar transceiver 3 is functioning normally when at least one of the following conditions is fulfilled:

[0072] - the detected signal level during an angular interval Θ comprised in the measurement angular interval 21 exceeds a minimum signal level 12. i

[0073] - the detected signal level during an angular interval Θ comprised in the measurement angular interval 21 changes with a certain angular change below a certain limit value. i

[0074] According to some aspects, the method comprises moving S200 the target object 7 along a measurement arc 10 at a distance L from the radar transceiver 3 during the measurement angular interval 21.

[0075] According to some aspects, a wire 17 is used to maintain the distance L.

[0076] According to some aspects, the method comprises monitoring S301 the azimuth angle Θ of the target object 7 over time as the target object moves around the measurement arc 10, and comparing S401 the monitored azimuth angle Θ with an expected azimuth angle trajectory.

[0077] According to some aspects, there are two or more target objects 7 in one or more corresponding fixed positions.

[0078] According to some aspects, a metal tube or a metal rod is used as the target object 7.

[0079] According to some aspects, the target object 7 is cylindrical and arranged vertically on a wheeled carriage 16.

[0080] According to some aspects, the minimum signal level 12 varies with the azimuth angle.

[0081] The present disclosure is not limited to the discussed examples, but can vary freely within the scope of the appended claims. For example, the radar transceiver can be of any suitable type, and can comprise suitable means according to some aspects, such as antennas, transmitters, receivers, control units, etc.

[0082] ​​The present disclosure relates to a measurement system 20 for controlling the functionality of a vehicle radar transceiver 3, wherein the measurement system 20 comprises a radar system 2 which in turn comprises a radar transceiver 3 and a control unit 4. The measurement system 20 further comprises a movable target object 7, and according to some aspects also an external computer device 18 connected to the control unit 4. According to some aspects, the computer device 18 is adapted to perform an analysis for determining if at least one of the following conditions is fulfilled. According to other aspects, no external computer is needed and all configuration and post-processing is performed within the radar control unit 4.

[0083] The control unit 4 can be constituted by one unit or by two or more distributed sub-units. The functionality of the measurement system according to the present disclosure can be shared in different ways between the control unit 4 of the radar system 2 and the external computer device 18.

[0084] Instead of a wheeled carriage, other alternatives can of course be envisaged. For example, the target object 7 can be moved along a track, however, this requires a more permanent installation. Such a track can allow the target device to be moved automatically during the measurement, where the azimuth angle Θ can be acquired via the position on the track.

[0085] According to some aspects, the measurement arc 10 is configured such that the distance L is not fixed, but varies for different azimuth angles Θ.

[0086] According to some aspects, there are two or more target objects 7 in one or more corresponding fixed positions. These fixed targets are not moved along the arc 10, and their positions are slightly different, such that multiple spot checks can be made. If there is no movable target object, this will result in a loss of information between the fixed targets, but no need for a moving target object.

[0087] In general, the present disclosure also relates to a measurement system 20 for controlling the functionality of a vehicle radar transceiver 3. The measurement system 20 comprises a radar system 2 which in turn comprises a radar transceiver 3 and a control unit 4, the measurement system 20 further comprising at least one target object 7. The measurement system 20 is adapted to: collect and store target data comprising received detected signal levels 21 obtained from reflected radar signals 6 reflected by the target object 7 during a measurement angular interval 21; and determine that the radar transceiver 3 is functioning properly when at least one of the following conditions is fulfilled:

[0088] - that the detected signal levels should exceed a minimum signal level 12 during the angular interval Θ comprised in the measurement angular interval 21; i

[0089] - that the detected signal levels should exceed a minimum signal level 12 during the angular interval Θ comprised in the measurement angular interval 21; i ​During the period, the detected signal level change for a certain angular change is below a certain limit.

[0090] According to some aspects, the measuring system 20 comprises a movable target object 7 which is movable along the measuring arc 10 at a distance L from the radar transceiver 3 during a measuring angular interval 21.

[0091] According to some aspects, the measuring system 20 comprises a line 17 adapted to hold the distance L.

[0092] According to some aspects, the measuring system 20 is adapted to monitor the azimuth angle Θ of the target object 7 over time as the target object moves around the measuring arc 10 and to compare the monitored azimuth angle Θ with an expected azimuth angle trajectory.

[0093] According to some aspects, the measuring system 20 comprises two or more target objects 7 in one or more corresponding fixed positions.

[0094] According to some aspects, the target object 7 is formed by a metal tube or a metal rod.

[0095] According to some aspects, the measuring system 20 comprises an external computer device 18 connected to the control unit 4, wherein the computer device 18 is adapted to perform an analysis for determining whether at least one of said following conditions is fulfilled.

Claims

1. A method for controlling the functioning of a vehicle radar transceiver (3), wherein the method comprises: transmitting (S100) radar signals (5); collecting and storing (S300) target data comprising received detected signal levels obtained from reflected radar signals (6) reflected by at least one movable target object (7) during a measurement angular interval (21); determining (S400) that the radar transceiver (3) is functioning properly when at least one of the following conditions is fulfilled: - the detected signal level exceeds a minimum signal level (12) during an angular interval (Θ i ) included in the measurement angular interval (21). - during an angular interval (θ i ) comprised in said measurement angular interval (21), the detected signal level variation for a certain angular variation is below a certain limit value, wherein the method comprises moving (S200) the target object (7) along a measurement arc (10) at a distance L from the radar transceiver (3) during the measurement angular interval (21).

2. The method according to claim 1, wherein a wire (17) is used to maintain the distance L.

3. The method according to claim 1, wherein the method comprises: monitoring (S301) the azimuth angle (0) of the target object (7) over time as the target object moves around the measurement arc (10), and comparing (S401) the monitored azimuth angle (0) with an expected azimuth angle trajectory.

4. The method according to claim 1, wherein there are two or more target objects (7) in one or more corresponding fixed positions.

5. The method according to any one of the preceding claims, wherein a metal tube or rod is used as the target object (7).

6. The method according to any one of claims 1-4, wherein the target object (7) is cylindrical and arranged vertically on a wheeled carriage (16).

7. The method according to any one of claims 1-4, wherein the minimum signal level (12) varies with azimuth angle.

8. A measurement system (20) for controlling the functioning of a vehicle radar transceiver (3), the measurement system (20) comprising a radar system (2) which in turn comprises the radar transceiver (3) and a control unit (4), the measurement system (20) further comprising at least one movable target object (7), wherein the measurement system (20) is adapted to: collect and store target data comprising received detected signal levels obtained from reflected radar signals (6) reflected by a target object (7) during a measurement angular interval (21); and determine that the radar transceiver (3) is functioning properly when at least one of the following conditions is fulfilled: - during an angular interval (θ i ) comprised in said measurement angular interval (21), said detected signal level should exceed a minimum signal level (12); - during an angular interval (θ i ) comprised in said measurement angular interval (21), the detected signal level variation for a certain angular variation is below a certain limit value, wherein the target object (7) is movable along a measurement arc (10) at a distance L from the radar transceiver (3) during the measurement angular interval (21).

9. The measurement system (20) according to claim 8, wherein the measurement system (20) comprises a wire (17) adapted to maintain the distance L.

10. The measuring system (20) according to claim 8, wherein the measuring system (20) is adapted to monitor the azimuth angle (0) of the target object (7) over time as the target object moves around the measuring arc (10) and to compare the monitored azimuth angle (0) with an expected azimuth angle trajectory.

11. The measuring system (20) according to claim 8, wherein the measuring system (20) comprises two or more target objects (7) in one or more corresponding fixed positions.

12. The measuring system (20) according to any one of claims 8 to 11, wherein the target object (7) is formed by a metal tube or a metal rod.

13. The measuring system (20) according to any one of claims 8 to 11, wherein the measuring system (20) comprises an external computer device (18) connected to the control unit (4), wherein the computer device (18) is adapted to perform an analysis for determining whether the at least one condition is fulfilled.

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