Radar system

• US 8,581,776 B2
• Filed: 12/18/2008
• Issued: 11/12/2013
• Est. Priority Date: 12/18/2008
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Tsunekawa, Jun
• Primary Examiner(s): Keith, Jack W
• Assistant Examiner(s): BYTHROW, PETER M
• Application Number:
  US13/123,914
• Publication Number:
  US 20110285574A1
• Time in Patent Office: 1,790 Days
• Field of Search: 342 70- 72, 342 94- 97, 342/104, 342/105, 342/115, 701/45, 701117-122, 340901-903, 340/436
• US Class Current: 342/70
• CPC Class Codes: G01S 13/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 13/723 by using numerical data
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• 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 7/40 Means for monitoring or calibrating
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

Provided is a radar system which calculates a track of a detected object and can determine whether or not the track is accurate. The radar system includes: a radar section for emitting an electromagnetic wave to an object and receiving a reflected wave reflected from the object to detect position information of the object; a track calculation section for calculating, periodically at a first cycle, a track along which the object moves, on the basis of the position information obtained from the radar section; a first speed calculation section for calculating a first speed at which the object moves, on the basis of pieces of the position information at two different time points having a time interval which is longer than the first cycle; and a track determination section for determining whether or not the track is accurate, on the basis of at least the first speed.

Claims

1. A radar system comprising:

a radar section for emitting an electromagnetic wave to an object and receiving a reflected wave reflected from the object to detect position information of the object;

a track calculation section for calculating, periodically at a first cycle, a track along which the object moves, on the basis of the position information obtained from the radar section;

a first speed calculation section for calculating a first speed at which the object moves, on the basis of pieces of the position information at two different time points having a time interval which is longer than the first cycle; and

a track determination section for determining whether or not the track is accurate, on the basis of at least the first speed,

wherein the track determination section determines that the track is not accurately calculated, when the first speed is lower than a predetermined threshold.

2. The radar system according to claim 1, wherein

the radar system is mounted in a vehicle,

the radar system further comprises a predicted collision time calculation section for calculating a predicted collision time to collision of the object with the vehicle, and

only when the predicted collision time satisfies a predetermined condition, the track determination section performs the determination concerning the track.

3. The radar system according to claim 2, wherein the track determination section performs the determination concerning the track when the predicted collision time is longer than a predetermined lower limit time, and does not perform the determination concerning the track when the predicted collision time is equal to or shorter than the lower limit time.

4. The radar system according to claim 2, wherein the track determination section performs the determination concerning the track when the predicted collision time is shorter than a predetermined upper limit time, and does not perform the determination concerning the track when the predicted collision time is equal to or longer than the upper limit time.

5. The radar system according to claim 4, wherein the track determination section performs the determination concerning the track when the predicted collision time is shorter than the upper limit time and longer than a lower limit time which is previously set so as to be shorter than the upper limit time, and does not perform the determination concerning the track when the predicted collision time is equal to or shorter than the lower limit time or when the predicted collision time is equal to or longer than the upper limit time.

6. The radar system according to claim 4, wherein the first speed calculation section calculates the first speed on the basis of:

a piece of the position information of the object at a current time; and

a piece of the position information of the object at a time point when the predicted collision time becomes shorter than the upper limit time.