Method for determining misalignment of a vehicle-mounted radar
By applying fast and slow filtering to the point cloud data of the vehicle radar and combining statistical principles, the system reduces misjudgments caused by angular misalignment due to violent vehicle movements, reduces unnecessary calibration, and improves the accuracy of the navigation system and the driving experience.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BOSCH AUTOMOTIVE PRODUCTS (SUZHOU) CO LTD
- Filing Date
- 2024-12-02
- Publication Date
- 2026-06-19
AI Technical Summary
In existing technologies, vehicle radar is prone to angle misjudgment when receiving data due to sudden acceleration or deceleration of the vehicle or going up or down slopes. Frequent calibration consumes computing resources and affects driving experience and safety.
By performing fast and slow filtering on the angles of targets in the radar-generated point cloud relative to the radar normal direction, combined with statistical principles and predetermined thresholds, the probability of misjudgment is reduced, and calibration is only performed when angular misalignment is confirmed.
It significantly reduces the possibility of false alarms due to radar angle misalignment, reduces unnecessary calibration, and improves the efficiency of the navigation system and the driving experience.
Smart Images
Figure CN119620009B_ABST
Abstract
Description
Technical Field
[0001] This application generally relates to a method for determining the presence of angular misalignment in vehicle-mounted radar in order to reduce the probability of false alarms due to angular misalignment. Background Technology
[0002] During vehicle manufacturing, radar, such as millimeter-wave radar, is fixedly installed in specific parts of the vehicle and calibrated to generate the appropriate computational processing for the in-vehicle navigation system during operation. For example, the data in the point cloud acquired by the radar can first be processed by a digital signal processor (DSP) to convert it into data that can be processed by the perception module in the in-vehicle navigation system. This data includes the angle of the target in the point cloud relative to the normal direction of the radar, which can be decomposed into horizontal and vertical angles relative to the ground. After the vehicle leaves the factory, the received data needs to be checked periodically during radar use to determine if the vehicle needs alignment due to changes in the radar's mounting orientation. In other words, if the radar's mounting orientation has indeed caused angular misalignment, the radar needs to be calibrated promptly to prevent unwanted deviations in the received data, which could lead to navigation distortion or even affect safe driving. Calibration typically takes a considerable amount of time, during which the in-vehicle navigation system will be unusable.
[0003] During normal use of a motor vehicle, aggressive driving, emergency braking, or driving uphill or downhill can cause the radar to misjudge angles based on the received data—even though the radar's actual installation orientation remains unchanged. However, frequently calibrating the radar solely based on these misjudgments (specifically, angle misjudgments) can consume excessive computing resources of the vehicle's navigation system, negatively impact the driving experience, and sometimes even compromise safe driving. Summary of the Invention
[0004] To address the aforementioned issues, this application aims to propose an improved method for determining whether a radar has angular misalignment, thereby reducing misjudgments of radar angular misalignment caused by factors such as motor vehicle uphill / downhill driving or rapid acceleration / deceleration, and providing a basis for accurate radar calibration.
[0005] According to one aspect of this application, a method for determining the presence of angular misalignment in an onboard radar is provided, comprising: determining the angle of a target in a point cloud generated by the radar relative to the normal direction of the radar, wherein the angle includes a horizontal angle and a vertical angle.
[0006] Perform fast filtering on the horizontal or vertical angle to obtain the fast angle of the horizontal or vertical angle.
[0007] For fast angles, whether horizontal or vertical, execute the following first sub-procedure, which includes the following steps:
[0008] 1) Calculate the variance and standard deviation of the fast angles for all horizontal or vertical angles within the time-domain window ending at the current time;
[0009] 2) If the variance is less than a non-zero positive integer multiple of the standard deviation, execute the second sub-procedure for the horizontal or vertical angle; otherwise, execute step 1) for the next time step.
[0010] The second sub-process for horizontal or vertical angles includes the following steps:
[0011] 3) Perform slow filtering on the horizontal or vertical angle to obtain the slow angle of the horizontal or vertical angle.
[0012] 4) If the slow angle of the horizontal angle or the slow angle of the vertical angle exceeds a predetermined limit for the slow angle of the horizontal angle or the slow angle of the vertical angle, then update the current slow angle to the predetermined limit for the slow angle of the horizontal angle or the slow angle of the vertical angle; otherwise, continue to execute step 3) for the next moment.
[0013] 5) If the fast angle of the horizontal angle or the fast angle of the vertical angle exceeds the predetermined limit, the vehicle radar is identified as having an angle misalignment and an alarm is issued to perform radar calibration.
[0014] Optionally, the first sub-process for the fast angle of the horizontal angle and the first sub-process for the fast angle of the vertical angle are executed synchronously; and / or the second sub-process for the horizontal angle and the second sub-process for the vertical angle are executed synchronously.
[0015] Optionally, in the second subprocess, a non-zero positive integer multiple of the standard deviation is three times the standard deviation.
[0016] Optionally, in the first sub-process, the second sub-process is executed only after a predetermined threshold is reached when the number of times the variance is identified as a non-zero positive integer multiple of the standard deviation has reached.
[0017] Optionally, in the first sub-process, the predetermined threshold for the horizontal angle is an integer between 2 and 100; and the predetermined threshold for the vertical angle is an integer between 2 and 100.
[0018] Optionally, in the first sub-process, when calculating the variance for the horizontal angle, the expected value for the horizontal angle is ±5.7°; and when calculating the variance for the vertical angle, the expected value for the vertical angle is ±6.3°.
[0019] Optionally, in the second sub-process, the predetermined limit for the horizontal angle is the same as the expected value for the horizontal angle; and / or, the predetermined limit for the vertical angle is the same as the expected value for the vertical angle.
[0020] Optionally, after issuing an alarm to perform calibration on the radar, the counter is reset to zero, and the first sub-process for fast angle for horizontal angle and / or fast angle for vertical angle is executed again.
[0021] Optionally, independent of the execution of the first sub-process and / or the second sub-process, if the vehicle is detected to be stationary for more than a predetermined time, it is determined that there is an angle misalignment in the vehicle radar and an alarm is issued to perform radar calibration.
[0022] Optionally, the vehicle-mounted radar is a forward-facing radar or an angle radar.
[0023] According to another aspect of this application, an in-vehicle domain controller is also provided, configured to connect to in-vehicle radar data and perform the steps of the aforementioned method.
[0024] According to another aspect of this application, a computer program product is also provided, comprising a computer program or instructions, characterized in that the computer program or instructions, when executed by a processor, implement the steps of the aforementioned method.
[0025] By employing the technical means described in this application, the possibility of false alarms due to radar angle misalignment caused solely by abnormal radar received data (rather than actual radar angle misalignment) can be significantly reduced, thereby reducing the probability of undesirable radar calibration, improving the driving experience for motor vehicle drivers, and ultimately improving the efficiency and accuracy of the navigation system. Attached Figure Description
[0026] A more comprehensive understanding of the principles and aspects of this application will be gained from the detailed description below, in conjunction with the accompanying drawings. It should be noted that the scale of the drawings may vary for clarity, but this will not affect the understanding of this application. In the drawings:
[0027] Figure 1 The diagram illustrates the angular relationship between the target in the point cloud and the radar when the radar is making an angular misalignment judgment.
[0028] Figure 2 A flowchart illustrating a method for determining angular misalignment of radar according to the prior art is shown schematically.
[0029] Figure 3 The diagram schematically illustrates the changes of each signal over time during the processing of the angle of a target relative to radar R in a point cloud generated from signals received by radar.
[0030] Figure 4 A flowchart illustrating a method for determining whether a radar has angular misalignment according to an embodiment of this application is shown schematically; and
[0031] Figure 5 A flowchart illustrating a method for determining whether a radar has angular misalignment according to another embodiment of this application is shown. Detailed Implementation
[0032] In the accompanying drawings of this application, features with the same structure or similar function are indicated by the same reference numerals.
[0033] For illustrative purposes only, Figure 1 This illustrates the angular relationship between a target in a point cloud received by the radar and the radar's normal direction. Figure 1 In the attached diagram, reference numeral R represents radar; reference numeral RN represents the normal direction of the radar, which can be defined by the normal direction of the main lobe of the energy emitted by the radar; reference numeral C represents a point cloud generated by the signal received by the radar, for example, the raw data received by the radar can be processed into this point cloud information by a DSP in a manner familiar to those skilled in the art; reference numeral O represents a target in the point cloud, for example, the target could be the purpose of navigation judgment in an in-vehicle navigation system. Figure 1 The left subplot shows the spatial relationship between radar R and point cloud C. Figure 1 The right subplot shows the target O and radar R in the point cloud C in a plane perpendicular to the normal direction RN of radar R, and the angular relationship between them. Figure 1 In the right sub-figure, the angle of target O relative to the normal direction RN of radar R can be decomposed relative to the ground into a horizontal angle AH and a vertical angle AV. Those skilled in the art will understand that the radar R designed in this application is a vehicle-mounted radar, including but not limited to vehicle-mounted forward-facing radars and angle radars. Therefore, the methods or steps described below are applicable to radars configured on motor vehicles, such as vehicle-mounted forward-facing radars and angle radars.
[0034] In judging radar angular misalignment, the main focus is on whether there are deviations in the horizontal angle AH and vertical angle AV sufficient to require radar calibration. Figure 2 This demonstrates a method for determining radar angular misalignment using existing technology. It's important to understand that, during the operation of a vehicle or radar, this determination is performed each time the radar receives and processes a signal. For example... Figure 2As shown, in step S100, the raw signal received by radar R is processed by DSP in any manner familiar to those skilled in the art. The obtained data includes the horizontal angle AH and the vertical angle AV of target O relative to radar R. In step S200, the horizontal angle AH or the vertical angle AV is filtered, for example, by using fast filtering FF and slow filtering SF, which are well known to those skilled in the art, to process the same horizontal angle AH or the same vertical angle AV respectively. The following explanation uses only the horizontal angle AH as an example. In step S200, a fast-filtered horizontal angle AHF (also called the fast angle) and a slow-filtered horizontal angle AHS (also called the slow angle) are generated. Next, in step S310, it is determined whether the slow angle AHS obtained in step S200 exceeds a predetermined limit T. HS If in step S310 it is determined that the slow angle AHS exceeds the predetermined limit T. HS In step S320, the current slow angle AHS is defined as the predetermined limit T. HS Then return to step S100 to restart the cycle of receiving and processing signals. If it is determined in step S310 that the slow angle AHS has not exceeded the predetermined limit T HS If not, the process returns directly to step S100 to restart the cycle of receiving and processing signals. Meanwhile, in step S300, it is determined whether the fast angle AHF obtained in step S200 exceeds a predetermined limit T. HS Wherein, the predetermined limit T HS It can be a limit value that has been updated in the previous cycle of receiving and processing signals, or a predetermined limit value T that is still used in the previous cycle of receiving and processing signals. HS If in step S300 it is determined that the fast angle AHF has exceeded the predetermined limit T. H If s, then proceed to step S330. In step S330, for example, the current signal reception and processing cycle of radar R can be stopped, and the calibration process of radar R can be initiated (not shown in the figure); or, an alarm for performing radar calibration can be issued. If it is determined in step S300 that the fast angle AHF has not exceeded the predetermined limit T H If s is not found, the process returns directly to step S100 to restart the cycle of receiving and processing the signal. For the vertical angle AV, the above process is performed synchronously. For example, in step S200, a fast-filtered vertical angle AVF (also called the fast angle) and a slow-filtered vertical angle AVS (also called the slow angle) are generated. Then, in step S310, it is determined whether the slow angle AVS obtained in step S200 exceeds a predetermined limit T. VS If in step S310 it is determined that the slow angle AVS exceeds the predetermined limit T. VSIn step S320, the current slow angle AVS is defined as the predetermined limit value T. VS Then return to step S100 to restart the cycle of receiving and processing signals. If it is determined in step S310 that the slow angle AVS has not exceeded the predetermined limit T VS If not, the process returns directly to step S100 to restart the cycle of receiving and processing signals. Meanwhile, in step S300, it is determined whether the fast angle AVF obtained in step S200 exceeds a predetermined limit T. VS Wherein, the predetermined limit T VS It can be a limit value that has been updated in the previous cycle of receiving and processing signals, or a predetermined limit value T that is still used in the previous cycle of receiving and processing signals. VS If in step S300 it is determined that the fast angle AVF has exceeded the predetermined limit T. V If s, then proceed to step S330. In step S330, for example, the current signal reception and processing cycle of radar R can be stopped, and the calibration process of radar R can be initiated (not shown in the figure); or, an alarm for performing radar calibration can be issued. If it is determined in step S300 that the fast angle AVF has not exceeded the predetermined limit T V If s, then return directly to step S100 to restart the cycle of receiving and processing signals for the next time.
[0035] exist Figure 2 In the method shown, if in each loop, regardless of whether the horizontal angle AH or the vertical angle AV, the fast angle AHF or AVF in step S300 has exceeded the predetermined limit T. H s or T V If s, then all need to go to step S330.
[0036] exist Figure 2In the existing methods described, all judgment steps are based on time-domain signals (e.g., the angle of target O in the point cloud relative to the normal direction RN of radar R). Therefore, certain abnormal signals in the time-domain signal can also cause radar R to be calibrated. Sometimes, these abnormal signals are not due to actual angular misalignment of radar R, but simply due to factors such as sudden acceleration or deceleration of a vehicle, or going uphill or downhill. In these cases, the installation orientation of radar R relative to the vehicle has not actually changed, but if radar R still needs to be calibrated according to the existing judgment method, it obviously consumes too much computational burden. At the same time, since the accuracy of the navigation system will inevitably decrease during the calibration process, it will affect the safety of driving or the driving experience. In addition, these abnormal signals may frequently occur during normal driving due to traffic congestion, road undulations, etc., causing the existing judgment method to cause frequent calibration of radar R, consuming a lot of computational resources and time, and affecting the driving experience of the driver.
[0037] Figure 3 The diagram schematically illustrates the time-varying characteristics of various signals during the processing of the angle of target O relative to radar R in a point cloud generated from signals received by radar R. Curve 1 represents the angle of target O in the point cloud processed by the DSP relative to the normal direction RN of radar R, which can be considered as the horizontal angle AH or the horizontal angle signal. Curve 2 represents the fast angle obtained after fast filtering of the real-time acquired horizontal angle AH. Curve 3 represents the slow angle obtained after slow filtering of the real-time acquired horizontal angle AH. Curve 4 represents a predetermined limit updated based on the slow angle and used to determine whether the fast angle exceeds the limit. It can be seen that abnormal signal peaks such as 1_A and 1_B exist in curve 1. If a method such as... Figure 2 If the existing technology method is used for judgment, these abnormal signal peaks will inevitably lead to the result of step S330. However, depending on the actual operating state of the vehicle, these abnormal signal peaks 1_A and 1_B are often only caused by the vehicle's rapid acceleration or deceleration or going uphill or downhill. Therefore, in order to eliminate the influence of these abnormal signal peaks 1_A and 1_B on the radar angle misalignment judgment result, a method for judging whether there is radar angle misalignment according to this application is introduced.
[0038] It should be understood that the methods and / or steps of the methods described below in this application can exist in the form of a computer program product, wherein the computer program product includes programs or instructions for implementing the methods and / or steps of the methods of this application, and such programs or instructions, when executed by a processor, can implement the methods and / or steps of the methods of this application. Within the scope of this application, the processor can be a processor or computing unit of the perception module of an in-vehicle navigation system or other processor for processing data received by the radar. Here, a processor can be understood as any suitable computer or computing unit capable of executing programs or instructions. Furthermore, an in-vehicle domain processor is typically configured in a motor vehicle. Such an in-vehicle domain processor can also be understood as a computer capable of implementing the methods and / or steps of the methods described in this application. The in-vehicle domain processor can be data-connected to the radar R (e.g., connected via an in-vehicle bus), thereby enabling it to acquire, store, and process the data actually received by the radar R.
[0039] The method for determining whether a radar has angular misalignment according to this application is based on the assumption that, under normal conditions, the angle RN of the target O relative to the normal direction of radar R within a certain time-domain window accurately reflects changes in radar angular misalignment and follows a random distribution, such as a normal distribution. Therefore, to eliminate the influence of changes in the angle RN of the target O relative to the normal direction of radar R that cannot accurately reflect radar angular misalignment on the determination result, statistical principles are used to determine whether the filtered fast angle changes of the angle RN of the target O relative to the normal direction of radar R recorded within a certain time-domain window accurately reflect the phenomenon of radar angular misalignment. Furthermore, since each radar calibration consumes certain computational resources, it is possible to save computational resources by comparing the fast angle with a predetermined limit only after the number of times accurately reflecting radar angular misalignment reaches a threshold.
[0040] See below for reference Figure 4 A flowchart illustrating a method for determining the presence of angular misalignment in a radar according to an embodiment of this application is provided.
[0041] In step S10, the raw signal received by radar R is processed by DSP in any manner familiar to the art to obtain data including the angle of target O relative to the normal direction RN of radar R, wherein the angle of target O relative to the normal direction RN of radar R can be divided into a horizontal angle AH and a vertical angle AV. In the illustrated embodiment, only the horizontal angle AH is used as an example to illustrate the method of this application. However, those skilled in the art should understand that the method of this application can also be implemented with the vertical angle AV, or the method of this application can be implemented with the horizontal angle AH and the vertical angle AV in parallel. It should be understood that the method steps described below are in the radar (e.g., Figure 1 The vehicle-mounted radar R shown will execute the commands after a certain period of time following its power-on, in order to facilitate the data processing steps related to the time-domain window mentioned later.
[0042] In step S11, the horizontal angle AH obtained in step S10 (here, the horizontal angle AH can be understood as the signal of the horizontal angle AH obtained in real time) is subjected to fast filtering (FF) processing to obtain the real-time (horizontal) fast angle. Then, in step S12, variance distribution statistics are performed on the real-time fast angles obtained in step S11 within the previous time-domain window length starting from the current time.
[0043] For example, the length of the time-domain window can be determined according to requirements such as computational burden and / or computational accuracy, and the length of the time-domain window can be constant or variable. Furthermore, the position of the time-domain window is defined by the current time (e.g., the time at which the horizontal angle AH involved in step S11 or S12 is located). Alternatively, the time-domain window can be considered as a sample space containing n samples (n is an integer greater than 1), which correspond to the n horizontal angles AH recorded within the time-domain window. The order of these n samples can correspond to the temporal order of each horizontal angle AH recorded within the time-domain window.
[0044] For this sample space, calculate the variance s. n For example, the formula for calculating variance can be as follows:
[0045]
[0046] Where, x i This represents the value of the i-th sample in the sample space (for example, it could be the value of the horizontal angle AH at time i in the time domain). This represents the expected value for a sample within the sample space. Taking the horizontal angle as an example, this expected value can be a pre-defined value, such as ±5.7°. For the horizontal angle, there are positive and negative (left and right) angles relative to the normal direction RN of the radar R. When a horizontal angle in one direction is considered positive, the expected value of that horizontal angle can be 5.7°; while when the opposite horizontal angle is considered negative, the expected value can be -5.7°. For the vertical angle, this expected value can be, for example, ±6.3°. For instance, when the upward vertical angle is considered positive, the expected value of that vertical angle can be 6.3°; while when the downward vertical angle is considered negative, the expected value can be -6.3°.
[0047] Next, for this sample space, the standard deviation σ is calculated. nFor example, the relationship between the standard deviation and the variance could be...
[0048] For example, in Figure 3 In the above time-domain window, LT represents t0, t1, t2, ..., t j These represent the processing performed at these times on the angle (curve 1, e.g., horizontal or vertical angle) of the target O in the point cloud processed by the DSP relative to the normal direction RN of the radar R, as mentioned in steps S100 to S200 above, where j can be an integer and greater than zero, and its magnitude can depend on the running time of the radar R. j -t j-1 | can be considered as the time-domain interval between adjacent angles in the time domain of a target O in the point cloud processed by the DSP relative to the normal direction RN of the radar R. The time-domain length of the time-domain window LT is, for example, for each t0, t1, t2, ..., t j It can be fixed, or alternatively, for t0, t1, t2, ..., t j Some or all of them can also change. It should be clear that in... Figure 3 The time points t0, t1, t2, ..., t shown in the figure j This is merely illustrative and does not represent the actual time-domain sampling point for curve 1.
[0049] For example, step S10 can be executed starting from time t0. This time t0 could be the moment when radar R has been running for a period of time (e.g., 1 second later), or it could be the moment immediately after radar R has been calibrated. For example, at time t0, all the fast-filtered fast angles of the horizontal angles within its corresponding time-domain window LT can be considered as samples in a sample space, and their variance s can be determined. n and standard deviation σ n For example, at time t j The corresponding time-domain window LT can be shifted in the time domain by a length |t relative to the time-domain window LT at time t0. j All horizontal angles within -t0|) are treated as fast-filtered fast angles within a sample space, and their variances s are determined. n and standard deviation σ n .
[0050] Then turn to Figure 4 In step S13, the standard deviation σ of the sample space is used. n The confidence level is determined by multiples of the standard deviation, such as three times the standard deviation, and the variance s of the sample space is also determined. nIs it less than the confidence level? If the judgment result of step S13 is yes, then proceed to step S14; if no, then proceed to step S10, and continue to process the raw signal received by radar R at the next moment using DSP in any manner familiar to the art, to obtain data including the angle of the target O relative to the normal direction RN of radar R.
[0051] In step S14, the counter J is incremented by 1. Then, in step S15, it is determined whether the counter J exceeds a threshold Jmax. For example, this threshold can be an integer greater than 1, such as a suitable integer between 2 and 50, or between 50 and 100, 200, or 300. Preferably, the threshold is 100. If the determination result of step S15 is negative, the process proceeds to step S10, where the raw signal received by radar R at the next moment is processed using the DSP in any manner familiar to the art to obtain data including the angle of the target O relative to the normal direction RN of radar R.
[0052] If the result of step S15 is yes, then proceed to step S100'. Starting from step S100', it is possible to refer to... Figure 2 The described method or method steps are Figure 4 The various steps of the method are executed. In the embodiments of this application, steps S12 and S13 described above are mainly used to determine whether the fast angle change accurately reflects the phenomenon of radar angle misalignment using statistical principles. In fact, step S14 exists to reduce the computational burden. This is because calibrating the radar consumes certain computational resources. If the process only proceeds to step S100' after the number of occurrences that accurately reflect the radar angle misalignment reaches a threshold, computational resources can be further saved. Of course, those skilled in the art will understand that step S14 can be omitted in one embodiment of this application. Furthermore, the selection of the threshold in step S14 is related to factors such as the performance of the computer hardware used to execute the method of this application and the calibration requirements for the radar.
[0053] In step S100', the raw signal received by radar R is processed by DSP in any manner familiar to those skilled in the art, and the obtained data includes the horizontal angle AH of target O relative to radar R. In step S200', the horizontal angle AH is filtered, for example, by using fast filtering FF and slow filtering SF, which are well known to those skilled in the art, to process the same horizontal angle AH, thereby producing a fast-filtered horizontal angle AHF (also called the fast angle) and a slow-filtered horizontal angle AHS (also called the slow angle). In an alternative or optional embodiment, the execution of step S100' can be for the current moment of the execution of steps S10 to S15 or the next moment. If the execution of step S100' is for the current moment of the execution of steps S10 to S15, the fast angle already obtained in step S11 can also be directly called without recalculation.
[0054] Next, in step S310', it is determined whether the slow angle AHS obtained in step S200 exceeds a predetermined limit T. HS If in step S310' it is determined that the slow angle AHS exceeds the predetermined limit T. HS Then, in step S320', the current slow angle AHS is defined as the predetermined limit value T. HS Then return to step S100' to restart the cycle of receiving and processing signals for the next time. If it is determined in step S310' that the slow angle AHS has not exceeded the predetermined limit T HS If the signal is not received, the process returns directly to step S100' to restart the cycle of receiving and processing the signal. Meanwhile, in step S300', it is determined whether the fast angle AHF obtained in step S200' exceeds a predetermined limit T. HS Wherein, the predetermined limit T HS It can be a limit value that has been updated in the previous cycle of receiving and processing signals, or a predetermined limit value T that is still used in the previous cycle of receiving and processing signals. HS If in step S300' it is determined that the fast angle AHF has exceeded the predetermined limit T. H If step S300' fails, proceed to step S330'. In step S330', for example, the current signal reception and processing cycle of radar R can be stopped, and the calibration process of radar R can be initiated (not shown in the figure), or an alarm can be issued to perform radar calibration. If in step S300' it is determined that the fast angle AHF has not exceeded the predetermined limit T... H If s, then directly return to step S100' to restart the cycle of receiving and processing signals. For example, after calibrating radar R or issuing an alarm for performing radar calibration, counter J can be reset to zero so that the execution of the above method steps can restart.
[0055] It should be clear that, in one embodiment of this application, the predetermined limit T is determined using a slow-angle AHS. HS The update can be performed synchronously during the processing of steps S10 to S15. Those skilled in the art should understand that step S10 can be started some time after the radar R is powered on or running, or alternatively, it can be started after the previous calibration of the radar R (e.g., after step S330' is performed above).
[0056] Figure 4 The method steps S10 to S15 shown are performed for horizontal angles, but steps S10 to S15 can also be performed simultaneously for vertical angles. Regardless of which angle steps S10 to S15 are performed for, if the judgment result of step S15 is yes, you can directly proceed to perform step S100' for the corresponding horizontal or vertical angle.
[0057] Figure 5 A flowchart of a non-limiting example of a method for simultaneously determining whether radar R has angular misalignment for horizontal angle AH and vertical angle AV is provided. It can be seen that in the initial processing steps S10 to S15 for horizontal angle AH and vertical angle AV, if the determination result of either step S15 for horizontal angle AH or step S15 for vertical angle AV is yes, the process jumps to the corresponding execution sub-processes S100' to S330' for horizontal angle AH or vertical angle AV. Specifically, in the execution sub-processes for vertical angle AV S100' to S330', in step S100', the raw signal received by radar R is processed using a DSP in any manner familiar to those skilled in the art, and the obtained data includes the vertical angle AV of target O relative to radar R. In step S200', the vertical angle AV is filtered, for example, by using fast filtering FF and slow filtering SF, which are well known to those skilled in the art, to process the same vertical angle AV, thereby generating a fast-filtered horizontal angle AVF (also called the fast angle) and a slow-filtered horizontal angle AVS (also called the slow angle). Next, in step S310', it is determined whether the slow angle AVS obtained in step S200 exceeds a predetermined limit T. VS If in step S310' it is determined that the slow angle AVS exceeds the predetermined limit T. HS Then, in step S320', the current slow angle AVS is defined as the predetermined limit value T. VS Then return to step S100' to restart the cycle of receiving and processing signals. If it is determined in step S310' that the slow angle AVS has not exceeded the predetermined limit T VSIf the signal is not received, the process returns directly to step S100' to restart the cycle of receiving and processing the signal. Meanwhile, in step S300', it is determined whether the fast angle AVF obtained in step S200' exceeds a predetermined limit T. VS Wherein, the predetermined limit T VS It can be a limit value that has been updated in the previous cycle of receiving and processing signals, or a predetermined limit value T that is still used in the previous cycle of receiving and processing signals. VS If in step S300' it is determined that the fast angle AVF has exceeded the predetermined limit T. V If step S300' fails, proceed to step S330'. In step S330', for example, the current signal reception and processing cycle of radar R can be stopped, and the calibration process of radar R can be initiated (not shown in the figure), or an alarm can be issued to perform radar calibration. If in step S300' it is determined that the fast angle AVF has not exceeded the predetermined limit T... V If s, then return directly to step S100' to restart the cycle of receiving and processing signals for the next time.
[0058] It should be clear that the aforementioned predetermined limit T V s can be the same as the desired value for the vertical angle, and / or the aforementioned predetermined limit T. H s can be the same as the expected value for the vertical angle.
[0059] According to another non-limiting embodiment of this application, in conjunction with the above references Figure 4 and 5 The described methods or method steps, or modifications thereof, independently can determine whether a vehicle is stationary and for how long based on other sensors of the vehicle, such as tire pressure sensors, speed sensors, etc. If the vehicle is detected to have remained stationary for more than a predetermined time (e.g., 60 seconds) after starting, an alarm is issued to perform radar calibration. An advantage of this embodiment is that if the vehicle remains stationary for an extended period after starting, there is a possibility of a collision. In this case, using a reference... Figure 4 and 5 The described methods or steps, or modifications thereof, may not be able to accurately determine whether there is angular misalignment in the vehicle radar, but the radar still needs to be calibrated to improve the accuracy of the navigation system.
[0060] Although specific embodiments of this application are described in detail herein, they are provided for illustrative purposes only and should not be construed as limiting the scope of this application. Furthermore, those skilled in the art will understand that the various embodiments described herein can be used in combination with each other. Various substitutions, modifications, and alterations can be conceived without departing from the spirit and scope of this application.
Claims
1. A method for determining angular misalignment in vehicle-mounted radar, comprising: Determine the angle of a target in a point cloud generated by radar relative to the normal direction of the radar, wherein the angle includes a horizontal angle and a vertical angle; Perform fast filtering on the horizontal or vertical angle to obtain the fast angle of the horizontal or vertical angle. For fast angles, whether horizontal or vertical, execute the following first sub-procedure, which includes the following steps: 1) Calculate the variance and standard deviation of the fast angles for all horizontal or vertical angles within the time-domain window ending at the current time. 2) If the variance is less than a non-zero positive integer multiple of the standard deviation, execute the second sub-procedure for the horizontal or vertical angle; otherwise, execute step 1) for the next time step. The second sub-process for horizontal or vertical angles includes the following steps: 3) Perform slow filtering on the horizontal or vertical angle to obtain the slow angle of the horizontal or vertical angle. 4) If the slow angle of the horizontal angle or the slow angle of the vertical angle exceeds a predetermined limit for the slow angle of the horizontal angle or the slow angle of the vertical angle, then update the current slow angle to the predetermined limit for the slow angle of the horizontal angle or the slow angle of the vertical angle; otherwise, continue to execute step 3) for the next moment. 5) If the fast angle of the horizontal angle or the fast angle of the vertical angle exceeds the predetermined limit, the vehicle radar is identified as having an angle misalignment and an alarm is issued to perform radar calibration.
2. The method of claim 1, wherein, The first sub-process for the fast angle of the horizontal angle and the first sub-process for the fast angle of the vertical angle are executed synchronously; and / or the second sub-process for the horizontal angle and the second sub-process for the vertical angle are executed synchronously.
3. The method of claim 2, wherein, In the second subprocess, a non-zero positive integer multiple of the standard deviation is three times the standard deviation.
4. The method according to any one of claims 1 to 3, characterized in that, In the first sub-process, the second sub-process is executed only after the number of times the variance is identified as a non-zero positive integer multiple of the standard deviation reaches a predetermined threshold.
5. The method of claim 4, wherein, In the first sub-process, the predetermined threshold for the horizontal angle is an integer between 2 and 100; and the predetermined threshold for the vertical angle is an integer between 2 and 100.
6. The method of claim 5, wherein, In the first sub-process, when calculating the variance for the horizontal angle, the expected value for the horizontal angle is ±5.7°; and when calculating the variance for the vertical angle, the expected value for the vertical angle is ±6.3°.
7. The method of claim 6, wherein, In the second sub-process, the predetermined limit for the horizontal angle is the same as the expected value for the horizontal angle; and / or, the predetermined limit for the vertical angle is the same as the expected value for the vertical angle.
8. The method of claim 7, wherein, After issuing an alarm to perform radar calibration, the counter is reset to zero, and the first sub-process for fast angle for horizontal angle and / or fast angle for vertical angle is executed again.
9. The method of claim 8, wherein, Independent of the execution of the first sub-process and / or the second sub-process, if the vehicle is detected to be stationary for more than a predetermined time, it is determined that there is an angle misalignment in the vehicle radar and an alarm is issued to perform radar calibration.
10. The method according to any one of claims 1 to 3, characterized in that, The vehicle-mounted radar is a forward-facing radar or an angle radar.
11. An onboard domain controller configured to connect to onboard radar data and perform the steps of the method according to any one of claims 1 to 10.
12. A computer program product comprising computer programs or instructions, characterized in that, When the computer program or instructions are executed by a processor, they perform the steps of implementing the method according to any one of claims 1 to 9.