Automotive radar

• US 7,132,976 B2
• Filed: 08/19/2005
• Issued: 11/07/2006
• Est. Priority Date: 01/20/2005
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Shinoda, Hiroshi, Nagasaku, Toshiyuki, Kondoh, Hiroshi
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US11/206,765
• Publication Number:
  US 20060158369A1
• Time in Patent Office: 445 Days
• Field of Search: 180167-169, 701/300, 701/301, 342/27, 342/28, 342 70- 81, 342/118, 342128-147, 342/158, 342/175, 342/195
• US Class Current: 342/70
• CPC Class Codes: G01S 13/449 Combined with MTI or Doppler processing circuits
• CPC Class Codes: G01S 13/52 Discriminating between fixed and moving objects or between objects moving at different speeds
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/468 by Triangulation, i.e. two antennas or two sensors determine separately the bearing, direction or angle to a target, whereby with the knowledge of the baseline length, the position data of the target is determined
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 2013/93272 in the back of the vehicles
• CPC Class Codes: G01S 2013/93274 on the side of the vehicles
• CPC Class Codes: G01S 7/2925 by using shape of radiation pattern
• CPC Class Codes: H01Q 25/02 providing sum and difference patterns H01Q25/04 takes precedence
• CPC Class Codes: H01Q 3/06 over a restricted angle
• CPC Class Codes: H01Q 3/08 for varying two co-ordinates of the orientation

Abstract

An automotive radar which can process signals at high speed to detect a target in a wide angle range is provided. The automotive radar comprises a transmitting antenna which emits an electromagnetic wave, two receiving antennas which receive the electromagnetic wave reflected by a target, an antenna plate on which the transmitting antenna and two receiving antennas are arranged. It also includes a drive which rotates the antenna plate in an azimuth direction, which corresponds to the direction of arrangement of the two receiving antennas, to scan a detection angle formed by the two receiving antennas. The drive has rest time between scans to stop rotation. The automotive radar also includes a signal processor which detects the azimuth angle of the target with respect to a reference direction during the rest time according to received signals from the two receiving antennas and the rotation angle of the antenna plate at rest.

Claims

1. An automotive radar comprising:

a transmitting antenna which emits an electromagnetic wave;

at least two receiving antennas which receive said electromagnetic wave reflected by a target;

an antenna substrate on which said transmitting antenna and said at least two receiving antennas are arranged;

a drive which, when the direction of arrangement of said at least two receiving antennas is an azimuth direction, rotates said antenna substrate in said azimuth direction to perform plural scans each from one antenna detection angle to an adjacent antenna detection angle of a plurality of antenna detection angles each formed by said at least two receiving antennas, and provides each stopping point of said antenna substrate between a scan and a next scan; and

a signal processor which detects the azimuth angle of a target with respect to a reference direction during said stopping point according to received signals from said at least two receiving antennas and the rotation angle of said antenna substrate at the stopping point.

2. The automotive radar according to claim 1, wherein said azimuth angle is detected from comparison of difference in amplitude or phase between received signals from said at least two receiving antennas.

3. The automotive radar according to claim 1, wherein said at least two receiving antennas serve also as the transmitting antenna.

4. The automotive radar according to claim 1, wherein a detection range is formed with said antenna detection angle, and said detection range at the stopping point partially overlaps with a detection range at the stopping point after the next scan.

5. The automotive radar according to claim 1, wherein said drive changes said scanning range to another scanning range.

6. The automotive radar according to claim 1, further comprising a radome covering said transmitting antenna and said at least two receiving antennas, wherein said radome contains a dielectric material and the upper face of said radome is curved in a scanning direction.

7. The automotive radar according to claim 1, wherein the intensity of an electromagnetic wave emitted from said transmitting antenna varies depending on a rotation angle at the stopping point.

8. The automotive radar according to claim 1, wherein said signal processor changes the level of said received signals depending on a rotation angle at the stopping point to detect said azimuth angle.

9. An automotive radar comprising:

a transmitting antenna which emits an electromagnetic wave;

at least two receiving antennas which receive said electromagnetic wave reflected by a target;

an antenna substrate on which said transmitting antenna and said at least two receiving antennas are arranged;

a drive which, when the direction of arrangement of said at least two receiving antennas is an azimuth direction, rotates said antenna substrate in an elevation angle direction perpendicular to said azimuth direction to perform plural scans, in the elevation angle direction, each from one first antenna detection angle to an adjacent first antenna detection angle of a plurality of first antenna detection angles formed by said at least two receiving antennas, and provides each stopping point of said antenna substrate between a scan and a next scan; and

a signal processor which detects the azimuth angle of a target in the elevation angle direction at the stopping point with respect to a reference direction during said stopping point according to received signals from said at least two receiving antennas and the rotation angle of said antenna substrate at the stopping point.

10. The automotive radar according to claim 9, wherein said drive rotates said antenna substrate in said azimuth direction to perform each scan, in the azimuth direction, from one second antenna detection angle to an adjacent second antenna detection angle of a plurality of second antenna detection angles formed by said at least two receiving antennas, and stops performing scan in the azimuth direction during said stopping point.

11. The automotive radar according to claim 10, wherein said azimuth angle is detected from comparison of difference in amplitude or phase between received signals from said at least two receiving antennas.

12. The automotive radar according to claim 10, wherein said at least two receiving antennas serve also as the transmitting antenna.

13. The automotive radar according to claim 10, wherein first and second detection ranges are formed with said first and second antenna detection angles, and said first and second detection ranges at the stopping point partially overlaps with first and second detection ranges at the stopping point after scans in the next elevation angle direction and azimuth direction respectively.

14. An automotive radar comprising:

a transmitting antenna which emits an electromagnetic wave;

at least four receiving antennas which receive said electromagnetic wave reflected by a target, arranged adjacent to each other horizontally and vertically;

an antenna substrate on which said transmitting antenna and said at least four receiving antennas are arranged;

a drive which, when said horizontal direction is an azimuth direction, rotates said antenna substrate in said azimuth direction and an elevation angle direction perpendicular to said azimuth direction to perform plural scans, in the azimuth direction and elevation angle direction, each from one antenna detection angle to an adjacent antenna detection angle of a plurality of antenna detection angles each formed by said at least four receiving antennas, and provides each stopping point of said antenna substrate between a scan and a next scan; and

a signal processor which detects the azimuth angle and elevation angle of a target with respect to a reference direction during said stopping point according to received signals from said at least four receiving antennas and the rotation angle of said antenna substrate at the stopping point in the azimuth direction and elevation angle direction.

15. The automotive radar according to claim 14, wherein said azimuth angle is detected from comparison of difference in amplitude or phase between received signals from horizontally aligned receiving antennas among said at least four receiving antennas, and said elevation angle is detected from comparison of difference in amplitude or phase between received signals from vertically aligned receiving antennas among said at least four receiving antennas.

16. The automotive radar according to claim 15, wherein said at least four receiving antennas serve also as the transmitting antennas.

17. The automotive radar according to claim 15, wherein a detection range is formed with said antenna detection angle, and said detection range at the stopping point partially overlaps with a detection range at the stopping point after a scan in the next elevation angle direction and azimuth direction.