Object sensing apparatus

• US 7,427,946 B2
• Filed: 04/10/2006
• Issued: 09/23/2008
• Est. Priority Date: 04/12/2005
• Status: Expired due to Fees

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Ando, Hiroyuki, Shingyoji, Masahito
• Primary Examiner(s): Gregory; Bernarr E
• Application Number:
  US11/401,753
• Publication Number:
  US 20060227037A1
• Time in Patent Office: 897 Days
• Field of Search: 342/27, 342/28, 342 70- 72, 342165-175, 342/195, 342/118, 342128-133, 342192-194, 342196-197, 180167-169, 701/300, 701/301
• US Class Current: 342/173
• CPC Class Codes: G01S 13/345 using triangular modulation
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/4017 of HF systems
• CPC Class Codes: G01S 7/4039 of sensor or antenna obstruction, e.g. dirt- or ice-coating

Abstract

While an FM-CW mode for sensing an object, in which a frequency of an electromagnetic wave transmitted from a transmission/reception antenna 6 is continuously modulated, and also, a CW mode for judging an abnormal condition, in which the frequency of the electromagnetic wave to be transmitted from the transmission/reception antenna 6 is not modulated are switched, an abnormal condition judging section judges an abnormal condition when a signal level of a reception signal of the FM-CW mode is smaller than, or equal to a first judging threshold value, and also, a signal level of a reception signal in the CW mode is smaller than, or equal to a second judging threshold value which is higher than the first judging threshold value.

Claims

1. An object sensing apparatus comprising:

transmission/reception section for transmitting an electromagnetic wave to a predetermined region and for receiving a reflection wave of the transmitted electromagnetic wave reflected from an object;

object sensing section for sensing the object based upon a reception signal received by the transmission/reception section; and

abnormal condition judging section for judging an abnormal condition based upon a signal level of the reception signal received by the transmission/reception section, wherein

the transmission/reception section is adapted to switch between an FM-CW mode in which a frequency of an electromagnetic wave to be transmitted is continuously modulated, and a CW mode in which the frequency of the electromagnetic wave to be transmitted is not modulated; and

the abnormal condition judging section judges an abnormal condition based upon a signal level of a reception signal in the FM-CW mode and a signal level of a reception signal in the CW mode.

2. The object sensing apparatus as claimed in claim 1, wherein the abnormal condition judging section judges the abnormal condition, when the signal level of the reception signal of the FM-CW mode is lees than or equal to a first judging threshold value, and the signal level of the reception signal in the CW mode is less than or equal to a second judging threshold value.

3. The object sensing apparatus as claimed in claim 2, wherein the first judging threshold value of the signal level of the reception signal in the FM-CW mode and the second judging threshold value of the signal level of the reception signal in the CW mode are different values from each other.

4. The object sensing apparatus as claimed in claim 3, wherein the first judging threshold value of the signal level of the reception signal in the FM-CW mode is less than the second judging threshold value of the signal level of the reception signal in the CW mode.

5. The object sensing apparatus as claimed in claim 2, wherein the first judging threshold value of the signal level of the reception signal in the FM-CW mode is less than the second judging threshold value of the signal level of the reception signal in the CW mode.

6. The object sensing apparatus as claimed in claim 1, wherein the abnormal condition judging section judges the abnormal condition, when a difference between a maximum value and a minimum value of the signal level of the reception signal in the FM-CW mode is less than or equal to a third judging threshold value, and a difference between a maximum value and a minimum value of the signal level of the reception signal in the CW mode is less than or equal to a fourth judging threshold value.