In-vehicle radar system

• US 20040150549A1
• Filed: 12/30/2003
• Published: 08/05/2004
• Est. Priority Date: 01/31/2003
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kumon, Hiroaki, Tamatsu, Yukimasa
• Granted Patent: US 6,812,883 B2
• Time in Patent Office: Days
• US Class Current: 342/70
• 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 13/72 for two-dimensional tracking, e.g. combination of angle and range tracking, track-while-scan radar
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93185 Controlling the brakes
• CPC Class Codes: G01S 2013/9319 Controlling the accelerator
• 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 2013/9325 for inter-vehicle distance regulation, e.g. navigating in platoons
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values

Abstract

A radar system mounted in a reference vehicle can detect a distance and orientation of a preceding vehicle to thereby compute a relative position of a width center of the preceding vehicle. A curving radius of the reference vehicle is then detected for computing a relative rotation angle between a direction from the reference vehicle and a longitudinal direction of the preceding vehicle. Relationship between a relative rotation angle and a lateral bias of the relative position of the width center is previously prepared in a map. The computed relative rotation angle is applied on the map, so that the corresponding lateral bias is obtained to correct the computed relative position of the width center of the preceding vehicle. Thus, the width center of the preceding vehicle moving in an adjacent lane can be accurately estimated.

Claims

1. An in-vehicle radar system mounted in a reference vehicle that is moving along a road, comprising:

radar means for radiating transmission radio waves and detecting reflection radio waves from a reflection object that receives a portion of the transmission radio waves;

recognizing means for recognizing, based on the detected reflection radio waves from the reflection object, a distance to the reflection object and an orientation of the reflection object with respect to the reference vehicle;

relative position computing means for computing, based on the recognized distance and the recognized orientation, a relative position of a width center of the reflection object with respect to the reference vehicle;

curving radius detecting means for detecting a curving radius of the road;

relative rotation angle computing means for computing, based on the computed relative position and the detected curving radius, a relative rotation angle of the reflection object that is an angle between a direction of the transmission radio waves advancing to the width center of the reflection object and a direction perpendicular to the width direction of the reflection object; and

correcting means for correcting the computed relative position of the width center of the reflection object by using the computed relative rotation angle.

2. The radar system of claim 1,

wherein the relative position of the reflection object is indicated by using a longitudinal direction of the reference vehicle and a lateral direction of the reference vehicle.

3. The radar system of claim 1,

wherein the relative rotation angle computing means computes the relative rotation angle based on a difference between a first angle and a second angle,

while the first angle relates to an angle between a longitudinal direction of the reference vehicle and the direction of the transmission radio waves advancing to the width center of the reflection object, and

wherein the second angle relates to an angle between the longitudinal direction of the reference vehicle and the direction perpendicular to the width direction of the reflection object.

4. The radar system of claim 1,

wherein the correcting means includes a lateral bias correcting map and lateral bias detecting means,

wherein the lateral bias correcting map includes a lateral bias of the computed relative position of the width center of the reflection object from an actual relative position of the width center, wherein the lateral bias is generated when the transmission radio waves transmitted to the actual relative position of the width center of the reflection object having the computed relative rotation angle, and

wherein the lateral bias detecting means obtains the lateral bias of the computed relative position of the width center by applying the relative rotation angle to the lateral bias correcting map.

5. The radar system of claim 4,

wherein, in the lateral bias correcting map, the lateral bias increases with increasing relative rotation angle.

6. The radar system of claim 4,

wherein, in the lateral bias correcting map, the lateral bias increases with decreasing distance to the reflection object under a condition where the relative rotation angle is fixed to a given angle.

7. The radar system of claim 1,

wherein the correcting means corrects the computed relative position of the width center of the reflection object when the recognized distance to the reflection object is a given distance or less.

8. The radar system of claim 1, further comprising:

size estimating means for estimating a size of the reflecting object,

wherein the correcting means corrects the computed relative position of the width center of the reflection object by using the computed relative rotation angle and the estimated size.

9. A bias correcting method for a reflection object recognized by an in-vehicle radar system mounted in a reference vehicle that is moving along a road, the in-vehicle radar system including:

radar means for radiating transmission radio waves and detecting reflection radio waves from the reflection object that receives a portion of the transmission radio waves; and

recognizing means for recognizing, based on the detected reflection radio waves from the reflection object, a distance to the reflection object and an orientation of the reflection object with respect to the reference vehicle,

the bias correcting method comprising steps of;

computing, based on the recognized distance and the recognized orientation, a relative position of a width center of the reflection object with respect to the reference vehicle;

detecting a curving radius of the road;

computing, based on the computed relative position and the detected curving radius, a relative rotation angle of the reflection object that is an angle between a direction of the transmission radio waves advancing to the width center of the reflection object and a direction perpendicular to the width direction of the reflection object; and

correcting the computed relative position of the width center of the reflection object by using the computed relative rotation angle.