Method of detecting a radar characteristic, a radar characteristic, detection apparatus, and a recording medium recording data for detecting a radar characteristic

• US 6,445,335 B1
• Filed: 11/08/2000
• Issued: 09/03/2002
• Est. Priority Date: 11/10/1999
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Tamatsu, Yukimasa
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US09/707,842
• Time in Patent Office: 664 Days
• Field of Search: 342/70, 342/71, 342/72, 342/89, 342/91, 342/93, 342/118, 342/165, 342/173, 342/174, 342/175, 342/195
• US Class Current: 342/70
• CPC Class Codes: G01S 7/4004 of parts of a radar system
• CPC Class Codes: G01S 7/4039 of sensor or antenna obstruction, e.g. dirt- or ice-coating
• CPC Class Codes: G01S 7/4056 specially adapted to FMCW
• CPC Class Codes: G01S 7/4091 during normal radar operation

Abstract

A radar wave reflected by a preceding automotive vehicle is received. The distance and the reception level of the received radar wave are repeatedly stored with relation therebetween. The reception levels are plotted with respect to distance. The distribution of the receptions levels is approximated with a linear equation as the characteristic of the radar apparatus. Variation in the distribution, that is, Y intercept of the linear equation represents the variation of the characteristic of the radar apparatus. A reference characteristic of the radar is measured with changing the distance to the preceding reflective object and the measured characteristic is measured with a moving preceding vehicle during actual traveling. The reference Y intercept is compared with the measured Y intercept to detect the deviation. Further, the divination amount or the measured value is classified to judge the cause of decries in the characteristic using conditional signals.

Claims

1. A method of detecting a characteristic of a radar apparatus for a vehicle on the basis of data of an object obtained by said radar apparatus, said data including distance data of said object and a level of a radar signal reflected by said object and received by said radar apparatus, comprising the steps of:

(a) repeatedly storing said distance data to said object and said level of said radar signal with relation therebetween; and

(b) detecting said characteristic of said radar apparatus from variation in distribution of said repeatedly stored distance data and levels of said radar signal.

2. A method as claimed in claim 1, further comprising the step of:

(c) detecting variation of said characteristic of said radar apparatus by comparing said distribution with a reference distribution.

15. A method as claimed in claim 1, further comprising the step of:

generating a control signal in accordance with said detected characteristic.

16. A method as claimed in claim 1, further comprising the steps of:

detecting a peak level of spread spectrum and comparing said peak level with a threshold value to detect said object;

detecting a relative speed of said object when said peak level is higher than said threshold value; and

determining whether said data of said object is subjected to said steps (a) and (b) in accordance with the result of said step of detecting said peak level.

17. A method as claimed in claim 2, further comprising the steps of:

effecting said step (a) and (b); and

storing said distribution as said reference distribution.

3. A radar apparatus characteristic detection apparatus detecting a characteristic of a radar apparatus for a vehicle on the basis of data of an object obtained by said radar apparatus, said data including distance data of said object and a level of a radar signal reflected by said object and received by said radar apparatus, comprising:

storing means for repeatedly storing said distance data and said level with relation therebetween; and

detecting means for detecting said characteristic of said radar apparatus from variation in distribution of said repeatedly stored distance data and levels.

4. A radar apparatus characteristic detection apparatus as claimed in claim 3, further comprising:

variation detection means for detecting variation of said characteristic of said radar apparatus, wherein said variation detection means includes comparing means for comparing said distribution with a reference distribution.

5. A radar apparatus characteristic detection apparatus as claimed in claim 4, further comprising:

means for determining a characteristic curve in accordance with said distribution and said comparing means compares said distribution with a reference characteristic curve.

6. A radar apparatus characteristic detection apparatus as claimed in claim 5, further comprising:

approximating means for approximating said distribution to provide a liner equation.

7. A radar apparatus characteristic detection apparatus as claimed in claim 6, further comprising:

calculation means for calculating an intercept of said linear equation and a reference intercept of a reference linear equation of said reference distribution, wherein said comparing means compares said intercept with said reference intercept.

8. A radar apparatus characteristic detection apparatus as claimed in claim 4, further comprising:

input means for inputting a signal from said vehicle.

9. A radar apparatus characteristic detection apparatus as claimed in claim 8, further comprising:

judging means for judging whether said variation of said characteristic of said radar apparatus is caused by the radar apparatus itself or an external reason in accordance with said signal inputted from said vehicle.

10. A radar apparatus characteristic detection apparatus as claimed in claim 3, further comprising:

judging means for judging that the object is moving in accordance with data from said radar and said storing means and said detection means are operated when said object is judged to be moving.

11. A radar apparatus characteristic detection apparatus as claimed in claim 4, further comprising:

recognizing means for recognizing said object in accordance with said data from said radar with a threshold value, and changing means for changing said threshold value when variation of said characteristic of said radar apparatus is detected.

12. A radar apparatus characteristic detection apparatus as claimed in claim 4, further comprising:

generating and outputting means for generating and outputting a mode control signal when said second detecting means detects said variation.

13. A recording medium for recording processing in detecting a characteristic of a radar apparatus for a vehicle on the basis of data of an object obtained by said radar apparatus, said data including distance data of said object and a level of a radar signal reflected by said object and received by said radar apparatus, said processing including the steps of:

(a) repeatedly storing said distance data to said object and said level of said radar signal with relation therebetween; and

(b) detecting said characteristic of said radar apparatus from variation in distribution of said repeatedly stored distance data and levels of said radar signal.

14. A recording medium as claimed in claim 13, wherein said processing further comprising the step of:

(c) detecting variation of said characteristic of said radar apparatus by comparing said distribution with a reference distribution.