Radar device and target detection method

• US 20090189814A1
• Filed: 01/26/2009
• Published: 07/30/2009
• Est. Priority Date: 01/29/2008
• Status: Active Grant

• Current Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Original Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Inventors: Sakaguchi, Masahiro, Moriuchi, Takumi, Tsunekawa, Jun, Iyoda, Motomi, Kawasaki, Tomoya, Asanuma, Hisateru
• Granted Patent: US 7,911,374 B2
• Time in Patent Office: Days
• US Class Current: 342/451
• CPC Class Codes: G01S 13/345 using triangular modulation
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/723 by using numerical data
• 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 2013/93275 in the bumper area
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured

Abstract

A target position is estimated in such a manner to maintain target position continuity, with high accuracy, even when the X coordinate displacement of the target is large. On a scan in which the target position is not detected, when a trajectory of the target in the past is within a predetermined region in the vicinity of the Y-axis, a position for estimate is a position having an X coordinate resulting from shifting, by a first displacement, the X coordinate estimated according to the trajectory, on a basis of the X coordinate of a previous position, while when the trajectory is not within the predetermined region, the position for estimate is a position having an X coordinate resulting from shifting, by a second displacement that is larger than the first displacement, the X coordinate estimated according to the trajectory, on a basis of the X coordinate of a previous position.

Claims

1. A radar device for scanning a predetermined angle range centered on a predetermined reference direction, comprising:

a target position detection unit which detects a position of a target within the angle range, on an XY coordinate plane having the reference direction as a Y-axis and a direction perpendicular to the reference direction as an X-axis, for each scanning; and

a target position estimation unit which, on a scan in which the target position is not detected, obtains a trajectory of the target on the basis of a first position of the target detected previously and a second position detected after the detection of the first position, and estimates a position having an X coordinate shifted by a first displacement from the X coordinate of the second position to be a position for detection by the scan when the trajectory is within a predetermined region in the vicinity of the Y-axis, and estimates a position having an X coordinate shifted by a second displacement larger than the first displacement from the X coordinate of the second position to be a position for detection by the scan when the trajectory is not within the predetermined region.

2. The radar device according to claim 1, wherein the target position estimation unit estimates a position using a position detected or estimated previously as the first or second position.

3. The radar device according to claim 1, further comprising a continuity determination unit which counts the number of times that displacements of a plurality of positions detected or estimated previously lie within a predetermined range, and outputs a detected position when the count value reaches a prescribed value.

4. The radar device according to any of claim 1, which is mounted on a mobile object, the reference direction being a direction oblique to a travel direction of the mobile object.

7. The radar device according to any of claim 2, which is mounted on a mobile object, the reference direction being a direction oblique to a travel direction of the mobile object.

8. The radar device according to any of claim 3, which is mounted on a mobile object, the reference direction being a direction oblique to a travel direction of the mobile object.

5. A target detection method comprising the steps of:

radar scanning a predetermined angle range centered on a predetermined reference direction;

detecting a position of a target within the angle range, on an XY coordinate plane having the reference direction as a Y-axis and a direction perpendicular to the reference direction as an X-axis, for each scanning; and

obtaining, on a scan in which the target position is not detected, a trajectory of the target on the basis of a first position of the target detected previously and a second position detected after the detection of the first position, and estimating a position having an X coordinate shifted by a first displacement from the X coordinate of the second position to be a position for detection on the scan when the trajectory is within a predetermined region in the vicinity of the Y-axis, and estimating a position having an X coordinate shifted by a second displacement larger than the first displacement from the X coordinate of the second position to be a position for detection on the scan when the trajectory is not within the predetermined region.

6. The target detection method according to claim 5, wherein in the step of estimating a position of the target, a position is estimated by using a position detected or estimated previously as the first or second position.