Automotive radar system with guard beam

• US 7,411,542 B2
• Filed: 02/10/2006
• Issued: 08/12/2008
• Est. Priority Date: 02/10/2005
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: O'Boyle, Michael E.
• Primary Examiner(s): Sotomayor; John B
• Application Number:
  US11/307,531
• Publication Number:
  US 20060267830A1
• Time in Patent Office: 914 Days
• Field of Search: 342 70- 72, 342/118, 342/159, 342/175, 340/903, 340/435, 340/436
• US Class Current: 342/70
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter

Abstract

A predictive collision radar system in a vehicle incorporates a first antenna and a guard antenna, the associated radiation patterns of which overlap with one another, but the radiation pattern of the guard antenna is broader than that of the first antenna. A comparison of signals from the first and guard antennas provides for rejecting targets that are not likely a threat to the vehicle. In one embodiment the first antenna is a multi-beam antenna with an electromagnetic lens, for example, either dielectric or planar, and a signal from a forward looking element thereof is compared with the signal from the guard antenna aligned therewith. In another embodiment, an electromagnetic lens is adapted to cooperate with the guard antenna so as to provide for forming the associated radiation pattern.

Claims

1. A method of detecting a target with a radar system, comprising:

a. generating a first beam of electromagnetic radiation in at least one first direction;

b. generating a second beam of electromagnetic radiation in at least one second direction, wherein a second direction of said at least one second direction is substantially aligned with a first direction of said at least one first direction, said second beam of electromagnetic radiation in said second direction overlaps a main lobe of said first beam of electromagnetic radiation in said first direction, said main lobe of said first beam of electromagnetic radiation in said first direction is adapted to illuminate a valid target to be detected by said radar system, and a substantial portion of said second beam of electromagnetic radiation extends beyond said first beam of electromagnetic radiation in at least one third direction so as to provide for illuminating a false target to be ignored by said radar system;

c. focusing at least one of said first beam of electromagnetic radiation and said second beam of electromagnetic radiation in at least one direction;

d. generating a first signal responsive to receiving first reflected electromagnetic radiation of said first beam of electromagnetic radiation, wherein said first reflected electromagnetic radiation is reflected by an environment of said radar system;

e. generating a second signal responsive to receiving second reflected electromagnetic radiation of said second beam of electromagnetic radiation, wherein said second reflected electromagnetic radiation is reflected by said environment of said radar system; and

f. processing said first and second signals so as to provide for discriminating said valid target from said false target.

2. A radar system, comprising:

a. at least one first antenna feed element adapted to transmit and receive a corresponding at least one first beam of electromagnetic radiation in at least one first direction, wherein said at least one first antenna feed element comprises a plurality of first antenna feed elements oriented in a corresponding plurality of different first directions;

b. at least one second antenna feed element adapted to transmit and receive a corresponding at least one second beam of electromagnetic radiation in at least one second direction, wherein said second beam of electromagnetic radiation in said second direction overlaps a main lobe of said first beam of electromagnetic radiation in said first direction, said main lobe of said first beam of electromagnetic radiation in said first direction is adapted to illuminate a valid target to be detected by said radar system, and a substantial portion of said second beam of electromagnetic radiation extends beyond said first beam of electromagnetic radiation in at least one third direction so as to provide for illuminating a false target to be ignored by said radar system; and

c. a processor, wherein said processor is adapted to receive a first signal received by a first antenna feed element of said at least one first antenna feed element, said processor is adapted to receive a second signal received by a second antenna feed element of said at least one second antenna feed element, wherein a direction of said first beam of electromagnetic radiation of said at least one first beam of electromagnetic radiation generated by said first antenna feed element is substantially similar to a direction of said second beam of electromagnetic radiation of said at least one second beam of electromagnetic radiation generated by said second antenna feed element, said first signal is responsive to reflected energy from said first beam of electromagnetic radiation, and said second signal is responsive to reflected energy from said second beam of electromagnetic radiation, said processor provides for processing said first and second signals so as to distinguish said valid target from said false target, wherein said valid target would be illuminated by both said first and second beams of electromagnetic radiation when said false target is illuminated substantially only by said second beam of electromagnetic radiation.

3. A radar system comprising:

a. at least one first antenna feed element adapted to transmit and receive a corresponding at least one first beam of electromagnetic radiation in at least one first direction, wherein said at least one first antenna feed element comprises a plurality of first antenna feed elements oriented in a corresponding plurality of different first directions;

b. at least one second antenna feed element adapted to transmit and receive a corresponding at least one second beam of electromagnetic radiation in at least one second direction, wherein said second beam of electromagnetic radiation in said second direction overlaps a main lobe of said first beam of electromagnetic radiation in said first direction, said main lobe of said first beam of electromagnetic radiation in said first direction is adapted to illuminate a valid target to be detected by said radar system, and a substantial portion of said second beam of electromagnetic radiation extends be beyond said first beam of electromagnetic radiation in at least one third direction so as to provide for illuminating a false target to be ignored by said radar system; and

c. a processor, wherein said processor is adapted to receive a first signal received by a first antenna feed element of said at least one first antenna feed element, said processor is adapted to receive a second signal received by a second antenna feed element of said at least one second antenna feed element, wherein a direction of said first beam of electromagnetic radiation of said at least one first beam of electromagnetic radiation generated by said first antenna feed element is substantially similar to a direction of said second beam of electromagnetic radiation of said at least one second beam of electromagnetic radiation generated by said second antenna feed element, said first signal is responsive to reflected energy from said first beam of electromagnetic radiation, and said second signal is responsive to reflected energy from said second beam of electromagnetic radiation, said processor provides for processing said first and second signals so as to distinguish said valid target from said false target, wherein said valid target would be illuminated by both said first and second beams of electromagnetic radiation when said false target is illuminated substantially only by said second beam of electromagnetic radiation; and

d. a first electromagnetic lens adapted to cooperate with said at least one first antenna feed element so as to provide for focusing said at least one first beam of electromagnetic radiation.

4. A radar system as recited in claim 3, wherein said first electromagnetic lens comprises a dielectric lens.

5. A radar system as recited in claim 4, wherein said dielectric lens comprises a spherical lens.

6. A radar system as recited in claim 4, wherein said first electromagnetic lens comprises a first planar electromagnetic lens comprising:

a. a plurality of corresponding first and second conductive patch elements;

b. at least one dielectric substrate, wherein said first and second conductive patch elements are separated from one another by said at least one dielectric substrate; and

a plurality of first delay elements, wherein each first delay element of said plurality of first delay elements is operative between corresponding said first and second conductive patch elements, and said plurality of first delay elements are adapted to provide for focusing said at least one first beam of electromagnetic radiation.

7. A radar system as recited in claim 6, further comprising a second electromagnetic lens adapted to cooperate with said at least one second antenna feed element so as to provide for focusing said at least one second beam of electromagnetic radiation in at least one direction.

8. A radar system as recited in claim 7, wherein said second electromagnetic lens comprises a second planar electromagnetic lens comprising:

a. a plurality of corresponding third and fourth conductive patch elements;

b. at least one dielectric substrate, wherein said third and fourth conductive patch elements are separated from one another by said at least one dielectric substrate; and

c. a plurality of second delay elements, wherein each second delay element of said plurality of second delay elements operative between corresponding said third and fourth conductive patch elements, and said plurality of second delay elements are adapted to provide for focusing said at least one second beam of electromagnetic radiation.

9. A radar system as recited in claim 8, wherein said plurality of corresponding first and second conductive patch elements are interconnected by a corresponding said plurality of first delay elements.

10. A radar system as recited in claim 8, wherein said plurality of corresponding third and fourth conductive patch elements are interconnected by a corresponding said plurality of second delay elements.

11. A radar system as recited in claim 6, wherein said plurality of corresponding first and second conductive patch elements are interconnected by a corresponding said plurality of first delay elements.

12. A radar system, comprising:

a. at least one first antenna feed element adapted to transmit and receive a corresponding at least one first beam of electromagnetic radiation in at least one first direction, wherein said at least one first antenna feed element comprises a plurality of first antenna feed elements oriented in a corresponding plurality of different first directions;

b. at least one second antenna feed element adapted to transmit and receive a corresponding at least one second beam of electromagnetic radiation in at least one second direction, wherein said second beam of electromagnetic radiation in said second direction overlaps a main lobe of said first beam of electromagnetic radiation in said first direction, said main lobe of said first beam of electromagnetic radiation in said first direction is adapted to illuminate a valid target to be detected by said radar system, and a substantial portion of said second beam of electromagnetic radiation extends beyond said first beam of electromagnetic radiation in at least one third direction so as to provide for illuminating a false target to be ignored by said radar system, wherein said at least one first antenna feed element and said at least one second antenna feed element are operatively associated with a first dielectric substrate; and

c. a processor, wherein said processor is adapted to receive a first signal received by a first antenna feed element of said at least one first antenna feed element, said processor is adapted to receive a second signal received by a second antenna feed element of said at least one second antenna feed element, wherein a direction of said first beam of electromagnetic radiation of said at least one first beam of electromagnetic radiation generated by said first antenna feed element is substantially similar to a direction of said second beam of electromagnetic radiation of said at least one second beam of electromagnetic radiation generated by said second antenna feed element, said first signal is responsive to reflected energy from said first beam of electromagnetic radiation, and said second signal is responsive to reflected energy from said second beam of electromagnetic radiation, said processor provides for processing said first and second signals so as to distinguish said valid target from said false target, wherein said valid target would be illuminated by both said first and second beams of electromagnetic radiation when said false target is illuminated substantially only by said second beam of electromagnetic radiation.

13. A radar system, comprising:

a. at least one first antenna feed element adapted to transmit and receive a corresponding at least one first beam of electromagnetic radiation in at least one first direction, wherein said at least one first antenna feed element comprises a plurality of first antenna feed elements oriented in a corresponding plurality of different first directions;

b. at least one second antenna feed element adapted to transmit and receive a corresponding at least one second beam of electromagnetic radiation in at least one second direction, wherein said second beam of electromagnetic radiation in said second direction overlaps a main lobe of said first beam of electromagnetic radiation in said first direction, said main lobe of said first beam of electromagnetic radiation in said first direction is adapted to illuminate a valid target to be detected by said radar system, and a substantially portion of said second beam of electromagnetic radiation extends beyond said first beam of electromagnetic radiation in at least one third direction so as to provide for illuminating a false target to be ignored by said radar system; and

c. a processor, wherein said processor is adapted to receive a first signal received by a first antenna feed element of said at least one first antenna feed element, said processor is adapted to receive a second signal received by a second antenna feed element of said at least one second antenna feed element, wherein a direction of said first beam of electromagnetic radiation of said at least one first beam of electromagnetic radiation generated by said first antenna feed element is substantially similar to a direction of said second beam of electromagnetic radiation of said at least one second beam of electromagnetic radiation generated by said second antenna feed element, said first signal is responsive to reflected energy from said first beam of electromagnetic radiation, and said second signal is responsive to reflected energy from said second beam of electromagnetic radiation, said processor provides for processing said first and second signals so as to distinguish said valid target from said false target, wherein said valid target would be illuminated by both said first and second beams of electromagnetic radiation when said false target is illuminated substantially only by said second beam of electromagnetic radiation; and

d. a second electromagnetic lens adapted to cooperate with said at least one second antenna feed element so as to provide for focusing said at least one second beam of electromagnetic radiation in at least one direction.

14. A radar system as recited in claim 13, wherein said second electromagnetic lens comprises a second planar electromagnetic lens comprising:

a. a plurality of corresponding third and fourth conductive patch elements;

b. at least one dielectric substrate, wherein said third and fourth conductive patch elements are separated from one another by said at least one dielectric substrate; and

c. a plurality of second delay elements, wherein each second delay element of said plurality of second delay elements is operative between corresponding said third and fourth conductive patch elements, and said plurality of second delay elements are adapted to provide for focusing said at least one second beam of electromagnetic radiation.

15. A radar system as recited in claim 14, wherein said plurality of corresponding third and fourth conductive patch elements are interconnected by a corresponding said plurality of second delay elements.

16. A method of detecting a target with a radar system, comprising:

a. generating a plurality of first beams of electromagnetic radiation in a corresponding plurality of first directions;

b. generating at least one second beam of electromagnetic radiation in at least one second direction, wherein a second direction of said at least one second direction is substantially aligned with at least one first direction of said plurality of first directions, said at least one second beam of electromagnetic radiation in said at least one second direction overlaps a main lobe of at least one first beam of electromagnetic radiation of said plurality of first beams of electromagnetic radiation in a corresponding at least one first direction of said plurality of first directions, said main lobe of said at least one first beam of electromagnetic radiation in said at least one first direction is adapted to illuminate a valid target to be detected by said radar system, and a substantial portion of said at least one second beam of electromagnetic radiation extends beyond said at least one first beam of electromagnetic radiation in at least one third direction so as to provide for illuminating a false target to be ignored by said radar system;

c. generating a first signal responsive to receiving first reflected electromagnetic radiation of said at least one first beam of electromagnetic radiation, wherein said first reflected electromagnetic radiation is reflected by an environment of said radar system;

d. generating a second signal responsive to receiving second reflected electromagnetic radiation of said at least one second beam of electromagnetic radiation, wherein said second reflected electromagnetic radiation is reflected by said environment of said radar system; and

e. processing said first and second signals so as to provide for discriminating said valid target from said false target.