阅读说明：本技术 移动平台上的雷达系统中的振动减轻 (Vibration mitigation in radar systems on mobile platforms ) 是由 O·朗曼 S·沙约威茨 S·维勒瓦尔 I·比莱克 于 2019-06-06 设计创作，主要内容包括：一种对移动平台上的雷达系统中的振动进行减轻的方法,包括获得由雷达系统的视场中的一个或多个物体对发射信号的反射而产生的接收信号。接收信号是三维数据立方体。该方法还包括处理接收信号以获得第一三维图以及第二三维图,基于利用第二三维图进行的第一探测来估计振动,以及从第一三维图中消除振动以获得校正后的第一三维图。进一步处理校正后的第一三维图得到校正后的第二三维图；以及利用校正后的第二三维图进行第二探测。(A method of mitigating vibration in a radar system on a moving platform includes obtaining a receive signal resulting from a reflection of a transmit signal by one or more objects in a field of view of the radar system. The received signal is a three-dimensional data cube. The method further includes processing the received signal to obtain a first three-dimensional map and a second three-dimensional map, estimating vibrations based on a first detection with the second three-dimensional map, and eliminating the vibrations from the first three-dimensional map to obtain a corrected first three-dimensional map. Further processing the corrected first three-dimensional image to obtain a corrected second three-dimensional image; and performing second detection by using the corrected second three-dimensional image.)

1. A method of mitigating vibration in a radar system on a mobile platform, the method comprising:

acquiring a received signal resulting from a reflection of a transmitted signal by one or more objects in a field of view of the radar system, wherein the received signal is a three-dimensional data cube;

processing the received signal to obtain a first three-dimensional map and a second three-dimensional map;

estimating the vibration based on a first detection performed using the second three-dimensional map;

eliminating the vibration from the first three-dimensional map to obtain a corrected first three-dimensional map;

obtaining a corrected second three-dimensional image by further processing the corrected first three-dimensional image; and

performing a second detection using the corrected second three-dimensional map.

2. The method of claim 1, wherein the radar system includes a plurality of transmit channels and receive channels, the transmit signals are chirped chirp continuous wave signals, obtaining the receive signals includes obtaining the three-dimensional data cube having a time dimension, a chirp dimension, and a channel dimension, and processing the receive signals includes performing a fast fourier transform, performing beamforming, and obtaining a first three-dimensional map having a distance dimension, a chirp dimension, and a beam dimension.

3. The method of claim 2, wherein the processing the received signal further comprises performing a second fast fourier transform on the first three-dimensional map and obtaining the second three-dimensional map having a range dimension, a doppler dimension, and a beam dimension, and the estimating of the vibration comprises estimating an amplitude and a frequency of the vibration.

4. The method of claim 2, wherein the obtaining the corrected second three-dimensional map from the corrected first three-dimensional map comprises performing a fast fourier transform on the corrected first three-dimensional map.

5. The method of claim 1, wherein the mobile platform is a vehicle and performing the second probe provides information for enhancing or automating vehicle operation.

6. A radar system that experiences vibration on a moving platform, the radar system comprising:

at least one receive antenna configured to obtain a receive signal resulting from a reflection of a transmitted signal by one or more objects in a field of view of the radar system, wherein the receive signal is a three-dimensional data cube; and

a processor configured to process the received signal to obtain a first three-dimensional map and a second three-dimensional map, estimate the vibration based on a first detection using the second three-dimensional map, cancel the vibration from the first three-dimensional map to obtain a corrected first three-dimensional map, obtain a corrected second three-dimensional map by further processing the corrected first three-dimensional map, and perform a second detection using the corrected second three-dimensional map.

7. The radar system of claim 6, wherein the radar system comprises a plurality of transmit channels and a plurality of receive channels, the transmit signals are chirp continuous wave signals, the three-dimensional data cube has a time dimension, a chirp dimension, and a channel dimension, and the processor is further configured to perform a fast Fourier transform and beamforming to obtain the first three-dimensional map having a distance dimension, a chirp dimension, and a beam dimension.

8. The radar system of claim 7, wherein the processor is further configured to perform a second fast Fourier transform on the first three-dimensional map to obtain the second three-dimensional map having the range dimension, Doppler dimension, and beam dimension, and the estimation of the vibration by the processor comprises estimating an amplitude and a frequency of the vibration.

9. The radar system of claim 7, wherein the processor is configured to obtain the corrected second three-dimensional map from the corrected first three-dimensional map by performing a fast fourier transform on the corrected first three-dimensional map.

10. The radar system of claim 6, wherein the mobile platform is a vehicle and the processor obtains information for enhancing or automating the vehicle operation based on performing the second detection.

Disclosure of Invention

In one exemplary embodiment, a method of vibration mitigation in a radar system on a moving platform includes obtaining a receive signal resulting from a reflection of a transmit signal by one or more objects in a field of view of the radar system. The received signal is a three-dimensional data cube. The method further includes processing the received signal to obtain a first three-dimensional map and a second three-dimensional map, estimating vibration based on performing a first probing using the second three-dimensional map, and eliminating vibration from the first three-dimensional map to obtain a corrected first three-dimensional map. Obtaining a corrected second three-dimensional map by further processing the corrected first three-dimensional map, and performing a second detection using the corrected second three-dimensional map.

In addition to one or more features described herein, the radar system includes a plurality of transmit channels and receive channels, the transmit signal is a chirped continuous wave signal called a chirp, and obtaining the receive signal includes obtaining a three-dimensional data cube having a time dimension, a chirp dimension, and a channel dimension.

In addition to one or more features described herein, processing the received signal includes performing a fast fourier transform and performing beamforming, and obtaining a first three-dimensional map having a distance dimension, a chirp dimension, and a beam dimension.

In addition to one or more features described herein, processing the received signal includes performing a second fast fourier transform on the first three-dimensional map and obtaining a second three-dimensional map having a range dimension, a doppler dimension, and a beam dimension.

In addition to one or more features described herein, estimating the vibration includes estimating an amplitude and a frequency of the vibration.

In addition to one or more features described herein, obtaining the corrected second three-dimensional map from the corrected first three-dimensional map includes performing a fast fourier transform on the corrected first three-dimensional map.

In addition to one or more features described herein, the mobile platform is a vehicle and the second probe provides information for enhancing or automating operation of the vehicle.

In another exemplary embodiment, a radar system that is subject to vibration on a moving platform includes at least one receive antenna to obtain a receive signal resulting from a reflection of a transmitted signal by one or more objects in the field of view of the radar system. The received signal is a three-dimensional data cube. The radar system further comprises a processor for processing the received signal to obtain a first three-dimensional map and a second three-dimensional map, estimating vibrations based on the first detection using the second three-dimensional map, eliminating vibrations from the first three-dimensional map to obtain a corrected first three-dimensional map, obtaining a corrected second three-dimensional map by further processing the corrected first three-dimensional map, and performing a second detection using the corrected second three-dimensional map.

In addition to one or more features described herein, the radar system includes a plurality of transmit channels and a plurality of receive channels, the transmit signals are chirped, continuous wave signals, and the three-dimensional data cube has a time dimension, a chirp dimension, and a channel dimension.

In addition to one or more features described herein, the processor performs a fast fourier transform and beamforming to obtain a first three-dimensional map having a distance dimension, a chirp dimension, and a beam dimension.

In addition to one or more features described herein, the processor performs a second fast fourier transform on the first three-dimensional map to obtain a second three-dimensional map having a range dimension, a doppler dimension, and a beam dimension.

In addition to one or more features described herein, the processor estimating the vibration includes estimating an amplitude and a frequency of the vibration.

In addition to one or more features described herein, the processor obtains a corrected second three-dimensional map from the corrected first three-dimensional map by performing a fast fourier transform on the corrected first three-dimensional map.

In addition to one or more features described herein, the mobile platform is a vehicle.

In addition to one or more features described herein, the processor obtains information for enhancing or automating vehicle operation based on performing the second detection.

In yet another exemplary embodiment, a vehicle includes a radar system subject to vibration. The radar system includes at least one receive antenna to obtain a receive signal resulting from a reflection of the transmit signal by one or more objects in the field of view of the radar system. The received signal is a three-dimensional data cube. The radar system further includes a processor for processing the received signal to obtain a first three-dimensional map and a second three-dimensional map, estimating vibration based on a first detection using the second three-dimensional map, eliminating vibration from the first three-dimensional map to obtain a corrected first three-dimensional map, obtaining a corrected second three-dimensional map by further processing the corrected first three-dimensional map, and performing a second detection using the corrected second three-dimensional map. The vehicle also includes a vehicle controller to obtain information from the second detection and to enhance or automate vehicle operation based on the information.

In addition to one or more features described herein, the radar system includes a plurality of transmit channels and a plurality of receive channels, the transmit signals are chirped, continuous wave signals, and the three-dimensional data cube has a time dimension, a chirp dimension, and a channel dimension.

In addition to one or more features described herein, the processor performs a fast fourier transform and beamforming to obtain a first three-dimensional map having a distance dimension, a chirp dimension, and a beam dimension.

In addition to one or more features described herein, the processor performs a second fast fourier transform on the first three-dimensional map to obtain a second three-dimensional map having a range dimension, a doppler dimension, and a beam dimension.

In addition to one or more features described herein, the processor obtains a corrected second three-dimensional map from the corrected first three-dimensional map by performing a fast fourier transform on the corrected first three-dimensional map.

The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description when read in connection with the accompanying drawings.

Drawings

Other features, advantages and details appear, by way of example only, in the following detailed description, the detailed description referring to the drawings in which:

FIG. 1 is a block diagram of a scenario involving a radar system in accordance with one or more embodiments;

FIG. 2 is a process flow of aspects of a method of mitigating vibration in a radar system configured on or in a vehicle, in accordance with one or more embodiments;

FIG. 3 is a process flow of other aspects of a method of mitigating vibration in a radar system configured on or in a vehicle, in accordance with one or more embodiments; and

FIG. 4 illustrates the effect of mitigating vibration in a radar system in accordance with one or more embodiments.

Detailed Description

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. As previously described, frequency modulated continuous wave signal radar transmits chirps and forms range-doppler plots from the received reflections. A reflection can be viewed as a three-dimensional data cube with time, chirp, and channel as three dimensions. Typical processing of the received reflections includes analog-to-digital conversion and fast fourier transform with respect to distance (referred to as the distance fast fourier transform). The result of the range fast fourier transform is an indication of the energy distribution within each transmit chirp that can be detected by the radar, and each receive channel and each transmit channel is associated with a different range fast fourier transform. Thus, the total number of range fast fourier transforms is the product of the number of chirps transmitted and the number of receive channels.

And then performing Doppler fast Fourier transform on the distance fast Fourier transform result. The doppler fast fourier transform is also a known process in radar detection and is used to obtain range-doppler plots for each receive channel. For each receive and transmit channel pair, all chirps are processed simultaneously for each range bin of the range-chip map (obtained using the range fast fourier transform). The result of the doppler fast fourier transform, i.e., the range-doppler plot, indicates the relative velocity of each detected object and its range. The number of doppler fast fourier transforms is the product of the number of range bins and the number of receive channels.

The result of digital beamforming is a range-doppler (relative velocity) map for each beam. Digital beamforming is also a known process and involves acquiring at each receiving element for each target reflection angle of arrival a vector value of a complex scalar obtained from a vector of received signals and a matrix of actually received signals. Digital beamforming provides azimuth and elevation angles for each detected object based on a threshold of the resulting vector's complex scalar. The final outputs from processing the received signals are range, doppler, azimuth, elevation, and amplitude for each object.

It is also noted that vibration of a platform (e.g., a vehicle) on or in which the radar system is located can affect signal-to-noise ratio and detection. As such, in accordance with one or more embodiments, the conventional process flow discussed above is augmented and rearranged to mitigate vibration in the radar system on the mobile platform. Specifically, digital beamforming is performed before doppler fast fourier transform, and the result is used to cancel vibration estimated from detection based on doppler fast fourier transform performed after the digital beamforming is performed.

According to an exemplary embodiment, fig. 1 is a block diagram of a scenario involving a radar system 110. The vehicle 100 shown in fig. 1 is an automobile 101. Radar system 110 is a multiple-input multiple-output (MIMO) system having several transmit channels 113a through 113m (commonly referred to as 113) and several receive channels 114a through 114n (commonly referred to as 114). The transmit channel 113 is shown as sharing an exemplary transmit antenna 111 that transmits the transmit signal 150, and the receive channel 114 is shown as sharing an exemplary receive antenna 112 that receives the resulting reflection 155 in the exemplary radar system 110 shown in fig. 2. In alternative or additional embodiments, radar system 110 may include a transceiver or additional transmit antenna 111 and a receive antenna 112. For example, there may be as many transmit antennas 111 as transmit channels 113 and as many receive antennas 112 as receive channels 114. Additionally, exemplary radar system 110 is shown under the hood of automobile 101. According to alternative or additional embodiments, one or more radar systems 110 may be located in vehicle 100 or elsewhere on vehicle 100. Another sensor 115 (e.g., a camera, sonar, and lidar system) is also shown. Information obtained by the radar system 110 and the one or more other sensors 115 may be provided to a controller 120 (e.g., an electronic control unit) for image or data processing, object recognition, and subsequent vehicle control.

The controller 120 may use the information to control one or more vehicle systems 130. In an exemplary embodiment, the vehicle 100 may be an autonomous vehicle and the controller 120 may use information from the radar system 110 as well as from other sources for known vehicle operation controls. In an alternative embodiment, the controller 120 may use information from the radar system 110 and other sources as part of known systems (e.g., collision avoidance systems, adaptive cruise control systems, and driver alerts) to enhance vehicle operation. The radar system 110 and one or more other sensors 115 may be used to detect an object 140, such as a pedestrian 145 shown in fig. 1. Controller 120 may include processing circuitry that may include application specific integrated circuits, electronic circuitry, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, combinational logic circuits, and/or other suitable components that provide the described functionality.

Fig. 2 is a process flow of various aspects of a method 200 of mitigating vibration in a radar system 110 configured on or in a vehicle 100 in accordance with one or more embodiments. The process shown in FIG. 2 yields the information needed to estimate and cancel the vibration, as further discussed with reference to FIG. 3. At block 210, obtaining the reflection 155 and performing analog-to-digital conversion means that the controller 120 includes an analog-to-digital converter and provides digital samples 215 for further processing. As previously described, the reflection 155 may be a three-dimensional data cube having three dimensions, time, chirp, and channel.

Performing a range fast fourier transform on the sample 215 at block 220 essentially refers to converting the time dimension of the three-dimensional cube to a range based on the known relationship between the time of flight and the range of the transmitted signal 150 and the reflection 155. The range fast fourier transform performed at block 220 produces a range-chirp-beam pattern 225. At block 230, digital beamforming is performed in a different order than conventional processing, which typically includes a doppler fast fourier transform prior to beamforming. At block 230, beamforming essentially refers to converting the channel dimensions of a three-dimensional cube into beams defining azimuth and elevation angles. The beamforming performed at block 230 produces a distance-chirp-beam pattern 235.

As shown in fig. 2, the range-chirp-beam pattern 235 is provided to block 350 (fig. 3) in addition to being used for doppler fast fourier transform at block 240. The doppler fast fourier transform performed at block 240 essentially refers to converting the chirp dimension of a three-dimensional cube to doppler, which represents the relative velocity of the object 140. The doppler fast fourier transform performed at block 240 produces a range-doppler-beam pattern 245. Because no vibration estimation and elimination is performed at this stage, detecting at block 250 refers to detecting using data affected by vibration. Performing a probe at block 250 produces probe signals 255 representing range, doppler (i.e., relative velocity), and beam (i.e., azimuth and elevation) when the energy exceeds a specified threshold in the range-doppler beam pattern 245. As shown in fig. 2, probing signal 255 is provided to block 310 (fig. 3).

Fig. 3 is a process flow of an additional aspect of a method 200 of mitigating vibration in a radar system 110 configured on or in a vehicle 100, in accordance with one or more embodiments. At block 310, probing the acquired probing signals 255 for estimating vibration parameters of each probing signal is performed at block 250. Each probe signal 255 includes an object doppler component and a vibration effect component. The probe signal 255 may be expressed as:

in equation 1, t is time, n is the exponent of the sample 215, f_dIs the Doppler frequency, A, of the object 140 associated with the probe signal 255_vibIs the amplitude parameter of the vibration, f_vibIs the frequency parameter of the vibration. At block 310, estimating vibration parameters A is performed_vibAnd f_vibThe following formula may be maximized based on the lookup value:

in equation 2, the index K is K chirps and q is the frequency.

At block 320, the processes include estimating a vibration parameter A from each of the detection signals estimated at block 310_vibAnd f_vibTo estimate the overall vibration parameters

And

the vibration parameter of each probe signal 255 is along a radial vector between radar system 110 and object 140 associated with probe signal 255. For each probe signal 255 (using index i)

Is obtained by using the vibration amplitude A_vibIs estimated by the above rotation function. The estimated azimuth az of each probe signal 255 is also used_iAnd elevation angle el_i：

Frequency of overall vibration

Does not change with the change of the arrival direction. Thus, for each probe signal 255:

when the I detection signals 255 are used to estimate the global vibration parameters

And

and the estimation precision is improved:

at block 330, vibration parameters are tracked

And

the filter (e.g., alpha filter) is used to smooth and essentially provide a weighted average of the parameter values of the previous estimate (m-1) for the current estimate (m). The weighting value α for the filter may be predetermined based on the platform (e.g., vehicle 100) and factors affecting radar system 110. the filtered value obtained at block 330 using equation 5 and equation 6 is:

the tracking (i.e., filtering) at block 330 is used for the vibration cancellation performed at blocks 340 and 350.

At block 340, the processes include projecting vibrations to all directions of arrival (all azimuth and elevation angles in the field of view). As mentioned before, the vibration frequency is the same in all directions of arrival. Therefore, the vibration frequency of each arrival direction is determined as:

by using a beam having an azimuth associated with each direction of arrival

And elevation angle

To obtain the vibration amplitude in each direction of arrival, such as:

based on the projected vibration, the vibration displacement s (t) of each beam can be determined from the results in equation 9 and equation 10 as:

at block 350, applying vibration cancellation refers to canceling the estimated vibration displacement s (t) at the raw data level. Each reflection 155 depends on its direction of arrival. Accordingly, the chirp dimension of the energy value (RCBmap) of the range-chirp-beam pattern 235 obtained from block 230 is corrected to eliminate the influence of the vibration, obtaining a corrected value C-CRBmap, as follows:

at block 360, the doppler fast fourier transform is repeatedly performed (as at block 240), but with the corrected values C-RCBmap of the range-chirp-beam pattern obtained at block 350. Detecting at block 370 using the range-doppler-beam pattern produced by the doppler fast fourier transform at block 360 refers to detecting the object 140 without the effect of vibration. Thus, detection 370 with higher signal-to-noise ratio and higher accuracy and elimination of false alarms caused by vibration may be performed based on the vibration estimation at block 310 and the vibration elimination at blocks 340 and 350.

FIG. 4 illustrates the effect of mitigating vibration in a radar system in accordance with one or more embodiments. Graphs 410-a and 410-B show range-doppler-beam results for a single range cell. Specifically, graph 410-A shows the range-Doppler-beam results from block 240 before vibration cancellation, and graph 410-B shows the range-Doppler-beam results from block 360 after vibration cancellation. The doppler cell is represented along axis 420 and the power in decibels (dB) is represented along axis 430. Graph 410-B has a higher signal-to-noise ratio than graph 410-a. Therefore, false detection of the object 140 is less likely to occur after the vibration is eliminated.

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope thereof. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed, but that the disclosure will include all embodiments falling within its scope.