Automotive radar using 3D printed luneburg lens

Patent metadata

Field	Value
Publication number	US-11340342-B2
Application number	US-201716325111-A
Country	US
Kind code	B2
Filing date	Aug 15, 2017
Priority date	Aug 15, 2016
Publication date	May 24, 2022
Grant date	May 24, 2022

Abstract

A high performance, low-cost automotive radar is designed by mounting receivers around a 3D printed Luneburg lens. With this configuration, the antenna radiation pattern is maintained for all angles, (which means no beam deformation). Further, the present radar is capable of performing detection at all azimuth and elevation angles with high angle resolution and broadband operation. The radar adaptively adjusts its spatial sensing pattern, sweeping frequency band, pulse repetition frequency and coherent processing interval according to the environment. This is accomplished by initially performing a rough scan, which updates sensing results via a narrow bandwidth waveform and wide beam scanning. When interested objects are identified, a high-resolution detailed scan is performed in a specific region of interest. In this way, a much more effective detection can be obtained. Moreover, a method of mitigating interference of the 3D printed Luneburg lens based radar and a method of improving the angle resolution using a lens based MIMO approach is disclosed.

First claim

What is claimed is:

1. An adaptive sensing method for scanning an environment surrounding an autonomous automobile, wherein the environment comprises a plurality of specific regions, the method comprising:
(a) providing a millimeter wave automotive radar comprising:
(i) one or more millimeter wave transceivers;
(ii) a 3D printed Luneburg lens having an upper frequency limit in a millimeter wave range; and
(iii) a plurality of antenna feed elements, operatively coupled to the one or more millimeter wave transceivers, mounted to a surface of the 3D printed Luneburg lens, each positioned in a determined direction; and
(iv) one or more processing elements operatively coupled to the plurality of antenna feed elements and to the one or more millimeter wave transceivers;

(b) performing a rough scan of the environment, the steps comprising:
(i) generating one or more wide beam patterns, via the plurality of processing elements, that are transmitted to the environment via the one or more millimeter wave transceivers;
(ii) receiving a first set of signals, resulting from interactions between the one or more wide beam patterns and the environment, via the one or more millimeter wave transceivers, wherein each signal has a signal strength, wherein the 3D printed Luneburg lens focuses the first set of signals prior to their reception by the plurality of antenna feed elements; and
(iii) processing the first set of signals via the plurality of processing elements, wherein if the signal strength of a signal processed by a processing element exceeds a first predetermined threshold, then the specific region of the processing element is a region of interest;

(c) performing a detailed scan of each region of interest, the steps comprising:
(i) generating a narrow scanning beam, via the plurality of antenna feed elements, that is transmitted to each region of interest via the one or more millimeter wave transceivers;
(ii) receiving a second set of signals via the one or more millimeter wave transceivers, wherein the second set of signals are a result of interactions between the narrow scanning beam and each region of interest, wherein the 3D printed Luneburg lens focuses the second set of signals prior to their reception by the plurality of antenna feed elements; and
(iii) processing the second set of signals, via the plurality of processing elements, to determine information about each region of interest
wherein performance of the rough scan and, subsequently, the detailed scan adaptively adjusts a spatial sensing pattern, a sweeping frequency band, a pulse repetition frequency, and a coherent processing interval according to the environment as the rough scan updates sensing results via the narrow scanning beam of the detailed scan.

2. The method of claim 1 , wherein the signal strength of the signal processed by a given processing element exceeds the first predetermined threshold when the signal interacts with one or more objects of interest, wherein processing of the second set of signals yields information about the one or more objects of interest.

3. The method of claim 2 , wherein a plurality of first predetermined thresholds is set for a plurality of distances to detect a presence of the one or more objects of interest each residing a distance, of the plurality of distances, away from the millimeter wave automotive radar.

4. The method of claim 3 , wherein the one or more millimeter wave transceivers comprises one or more millimeter wave receivers and one or more millimeter wave transmitters.

5. The method of claim 4 , wherein a multiple input multiple output (“MIMO”) technique is employed to improve the angular resolution of the millimeter wave automotive radar, wherein the MIMO technique comprises:
(a) measuring a magnitude and a phase of the one or more millimeter wave receivers for each millimeter wave transmitter;
(b) calculating a plurality of phase differences for different target directions between each of the millimeter wave transmitters;
(c) compensating for the plurality phase differences; and
(d) coherently adding a plurality of radar results from different millimeter wave transmitters to generate a scanning beam narrower than a half power beam width of the 3D printed Luneburg lens,
wherein the scanning beam is transmitted to each region of interest as the narrow scanning beam.

6. The method of claim 5 , wherein an interference suppression technique is applied to remove interference from a received signal, including the first and second set of signals, wherein the interference suppression technique is performed in a time domain of the received signal and comprises the steps of:
(a) measuring an amplitude of the received signal,
(b) determining if the amplitude exceeds a second predetermined threshold, and
(c) excising a portion of the amplitude of the received signal exceeding the second predetermined threshold.

7. The method of claim 6 , wherein each processing element comprises a memory operatively coupled to a processor executing one or more sets of instructions stored in the memory, wherein the one or more sets of instructions comprises generating the one or more wide beam patterns and the narrow scanning beam, processing the first set of signals and the second set of signals, and executing the MIMO and interference techniques, wherein the memory further stores the plurality of first predetermined thresholds and the second predetermined threshold.

8. The method of claim 1 , wherein the one or more wide beam patterns and the narrow scanning beam are transmitted to the environment through one or more channels of a millimeter wave spectrum, wherein an opportunity spectrum access (“OSA”) is estimated to determine an availability of the one or more channels for a given period of time.

9. The method of claim 8 , wherein Partially Observable Markov Decision Process is used to estimate the OSA for the millimeter wave automotive radar.

10. The method of claim 1 , wherein step (c) is iterated a determined number of times, wherein each iteration further narrows a number of the regions of interest and/or yields information about each region of interest in increasing detail.

11. A millimeter wave automotive radar effective for scanning an environment surrounding an autonomous automobile, wherein the environment comprises a plurality of specific regions, the radar comprising:
(a) one or more millimeter wave transceivers;
(b) a 3D printed Luneburg lens having an upper frequency limit in a millimeter wave range;
(c) a plurality of antenna feed elements, operatively coupled to the one or more millimeter wave transceivers, mounted to a surface of the 3D printed Luneburg lens, each positioned in a determined direction; and
(d) one or more processing elements operatively coupled to the plurality of antenna feed elements and to the one or more millimeter wave transceivers;
wherein a rough scan of the environment is performed, via one or more wide beam patterns generated by the one or more processing elements, wherein the one or more wide beam patterns are transmitted to the environment via the one or more millimeter wave transceivers, wherein a first set of signals are received by the one or more millimeter wave transceivers, wherein the first set of signals are processed by the one or more processing elements to determine one or more regions of interest,
wherein a detailed scan is then performed by generating and transmitting a narrow scanning beam to scan the one or more regions of interest, which results in a second set of signals received by the one or more millimeter wave transceivers, wherein the second set of signals are processed, via the one or more processing elements, to determi

Assignees

• Univ Arizona

Inventors

• Xin Hao
• Liang Min
• Cao Siyang

Classifications

• G05D2111/30

  Radio signals · CPC title

• B33Y80/00

  Products made by additive manufacturing · CPC title

• H01Q1/3233

  particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems · CPC title

• G01S13/931

  of land vehicles · CPC title

• H01Q21/29

  Combinations of different interacting antenna units for giving a desired directional characteristic (H01Q25/00 takes precedence) · CPC title