Radar device and target angle detection method

• US 20090207071A1
• Filed: 01/26/2009
• Published: 08/20/2009
• Est. Priority Date: 01/29/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation, Toyota Motor Corporation
• Original Assignee: Fujitsu Ten Limited (DENSO Corporation), Toyota Motor Corporation
• Inventors: Kinoshita, Motohide, Tsunekawa, Jun, Iyoda, Motomi, Kawasaki, Tomoya, Asanuma, Hisateru
• Granted Patent: US 8,054,216 B2
• Time in Patent Office: Days
• US Class Current: 342/156
• CPC Class Codes: G01S 13/4454 phase comparisons monopulse, i.e. comparing the echo signals received by an interferometric antenna arrangement

Abstract

A radar device has a plurality of receiving antennas which receive, as a reception wave, a radar wave sent in a predetermined reference direction and reflected by a target; a phase difference detection unit which detects a first phase difference of the reception wave received by a first receiving antenna pair that is spaced by a first gap, and a second phase difference of the reception wave received by a second receiving antenna pair that is spaced by a second gap smaller than the first gap; and an angle detection unit which performs a first process of determining, as a detection angle, an angle of the target relative to the reference direction being a mutually coincident angle from among a plurality of first angles corresponding to the first phase difference and a plurality of second angles corresponding to the second phase difference. The radar device allows expanding an angle detection range without reducing the resolution of the angle corresponding to the second phase difference.

Claims

1. A radar device, comprising:

a plurality of receiving antennas which receive, as a reception wave, a radar wave sent in a predetermined reference direction and reflected by a target;

a phase difference detection unit which detects a first phase difference of the reception wave received by a first receiving antenna pair that is spaced by a first gap, and a second phase difference of the reception wave received by a second receiving antenna pair that is spaced by a second gap smaller than the first gap; and

an angle detection unit which performs a first process of determining, as a detection angle, an angle of the target relative to the reference direction being a mutually coincident angle from among a plurality of first angles corresponding to the first phase difference and a plurality of second angles corresponding to the second phase difference.

2. The radar device according to claim 1,

wherein the mutually coincident angle comprises an average of the first and second angles that are closest to each other.

3. The radar device according to claim 1,

wherein the angle detection unit repeats the first process, and when a difference in detection angles for a predetermined number of times in the past lies within a predetermined range, the angle detection unit performs, instead of the first process, a second process of determining, as a current detection angle, an average of a third angle that is closest to a previous detection angle, from among the plurality of first angles, and a fourth angle that is closest to a previous detection angle, from among the plurality of second angles.

4. The radar device according to claim 3,

wherein when a difference between a last-but-one detection angle and a previous detection angle by the second process lies outside the predetermined range, the angle detection unit performs the first process, and when the difference lies within the predetermined range, the angle detection unit performs the second process.

5. The radar device according to claim 1,

wherein the phase difference detection unit further detects a third phase difference of the reception wave received by a third receiving antenna pair that is spaced by a third gap that is smaller than the second gap, and

the angle detection unit extracts a first, a second and a third angle that are closest to one another from among the plurality of first angles, the plurality of second angles and a plurality of third angles corresponding to the third phase difference, and determines, as the detection angle, an average of the extracted first, second and third angles.

6. The radar device according to claim 5,

wherein the first, second and third receiving antenna pairs are a combination of two antennas from among three antennas that are spaced apart by dissimilar gaps.

7. An angle detection method, comprising:

a step of receiving, as a reception wave, a radar wave sent in a predetermined reference direction and reflected by a target;

a phase difference detection step of detecting a first phase difference of the reception wave received by a first receiving antenna pair that is spaced by a first gap, and a second phase difference of the reception wave received by a second receiving antenna pair that is spaced by a second gap smaller than the first gap; and

an angle detection step of performing a first process of determining, as a detection angle, an angle of the target relative to the reference direction being a mutually coincident angle from among a plurality of first angles corresponding to the first phase difference and a plurality of second angles corresponding to the second phase difference.

8. The angle detection method according to claim 7,

wherein the mutually coincident angle comprises an average of the first and second angles that are closest to each other.

9. The angle detection method according to claim 7,

wherein the angle detection step comprises repeating the first process, and when a difference in detection angles for a predetermined number of times in the past lies within a predetermined range, performing, instead of the first process, a second process of determining, as a current detection angle, an average of a third angle that is closest to a previous detection angle, from among the plurality of first angles, and a fourth angle that is closest to a previous detection angle, from among the plurality of second angles.

10. The angle detection method according to claim 9,

wherein the angle detection step comprises performing the first process when a difference between a last-but-one detection angle and a previous detection angle by the second process lies outside the predetermined range, and performing the second process when the difference lies within the predetermined range.