RADAR DEVICE AND AZIMUTH ANGLE DETECTION METHOD

• US 20100134344A1
• Filed: 08/07/2008
• Published: 06/03/2010
• Est. Priority Date: 08/08/2007
• Status: Active Grant

• Current Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Original Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Inventors: Uesato, Yoshihide
• Granted Patent: US 8,400,350 B2
• Time in Patent Office: Days
• US Class Current: 342/156
• CPC Class Codes: G01S 13/34 using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• 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 3/46 using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: G01S 7/4026 Antenna boresight
• CPC Class Codes: G01S 7/403 in azimuth, i.e. in the horizontal plane
• CPC Class Codes: G01S 7/4091 during normal radar operation

Abstract

An electronic scanning radar device that detects an azimuth angle of a target based on a phase difference between a first pair of received waves received by a first pair of antennas separated by a prescribed distance, and combines the first pair of received waves and generates a first composite wave. The composite wave has a steep antenna pattern, for which the amount of level change is large for the amount of change in azimuth angle, and an azimuth angle judgment unit performs true/false judgment in which a detected azimuth angle is judged to be true when the level of the above first composite wave is equal to or above a reference value, and the azimuth angle is judged to be false when the level is below the reference value.

Claims

1. A radar device, which transmits radar waves in a reference direction, receives the radar waves reflected by a target as received waves, and detects an azimuth angle of the target relative to the reference direction, comprising:

an azimuth angle detection unit which detects the azimuth angle based on a phase difference between a first pair of received waves received by a first pair of antennas separated by a prescribed distance;

a composite wave generation unit which combines the first pair of received waves and generates a first composite wave; and

an azimuth angle judgment unit which performs true/false judgment in which the detected azimuth angle is judged to be true when the level of the first composite wave at this detected azimuth angle is equal to or greater than a reference value, and the detected azimuth angle is judged to be false when the level is lower than the reference value.

2. The radar device according to claim 1, further comprising a phase shifter which shifts the phase of either received wave among the first pair of received waves,

wherein the composite wave generation unit generates a second composite wave from a second pair of received waves comprising a received wave the phase of which has been shifted, and the azimuth angle judgment unit performs true/false judgment in which the detected azimuth angle is judged to be true when the level of either of the first or second composite wave at this detected azimuth angle is equal to or greater than a reference value, and the detected azimuth angle is judged to be false in other cases.

3. The radar device according to claim 1, further comprising a phase shifter which shifts the phase of either received wave among a third pair of received waves that are received by a second pair of antennas separated by a distance greater than that of the first pair of antennas,

wherein the composite wave generation unit generates, from a fourth pair of received waves comprising a received wave the phase of which has been shifted, a third composite wave the level peak of which is formed at an edge portion of an azimuth angle range in which the level of the first composite wave is distributed, and the azimuth angle judgment unit performs true/false judgment in which the detected azimuth angle is judged to be true when the level of either of the first or third composite wave at this detected azimuth angle is equal to or greater than a reference value, and the detected azimuth angle is judged to be false in other cases.

4. An azimuth angle detection method for detecting an azimuth angle of a target relative to a reference direction by a radar device which transmits radar waves in the reference direction, and receives the radar waves reflected by the target as received waves, comprising:

a step of detecting the azimuth angle based on a phase difference between a pair of received waves received by a pair of antennas separated by a prescribed distance;

a step of generating a composite wave of the pair of received waves; and

a step of performing true/false judgment in which the detected azimuth angle is judged to be true when the level of the composite wave at this detected azimuth angle is equal to or greater than a reference value, and the detected azimuth angle is judged to be false when the level is lower than the reference value.