Object detecting device

• US 6,992,613 B2
• Filed: 09/01/2004
• Issued: 01/31/2006
• Est. Priority Date: 09/02/2003
• Status: Expired due to Fees

• Current Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Original Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Inventors: Yoneda, Kimihisa
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US10/930,903
• Publication Number:
  US 20050046606A1
• Time in Patent Office: 517 Days
• Field of Search: 342/27, 342/28, 342/59, 342 70- 72, 342 82-103, 342/118, 342128-147, 342/158, 342/175, 342189-197, 342450-465, 342/442, 340/928, 701/300, 701/301, 180167-169
• US Class Current: 342/59
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence

Abstract

An object detecting device is provided whereby the number and size of detected objects can be determined without making the construction of the device more complex and the cost of components higher. The object detecting device includes multiple transmitter-receivers for transmitting radio waves and receiving reflected waves, each of the transmitter-receivers receiving both a reflected wave of a radio wave transmitted by itself and reflected waves of radio waves transmitted by other transmitter-receivers, a path-by-path reception distance computing unit for computing the path-by-path reception distance of every reflected wave and an object determination element for determining the number and/or size of detected objects based on the relationship between the reception distances computed by the path-by-path reception distance computing unit.

Claims

1. An object detecting device, comprising:

a plurality of transmitter-receivers for transmitting radio waves and receiving reflected waves, wherein each of the transmitter-receivers receives both a reflected wave of a radio wave transmitted by itself and reflected waves of radio waves transmitted by other transmitter-receivers;

a path-by-path reception distance computing unit for computing the path-by-path reception distance of every reflected wave; and

an object determination element for determining at least one of a number and a size of detected objects based on a relationship between the reception distances computed by the path-by-path reception distance computing unit.

2. An object detecting device according to claim 1, wherein:

the object determination element determines that there is only one detected object which has a small size when points of intersection of each arc with each transmitter-receiver as a center and a distance to the detected object as a radius, and each elliptic curve passing through the detected object with two of the transmitter-receivers as the center are approximated roughly to one point.

3. An object detecting device according to claim 1, wherein:

the object determination element determines that there is more than one detected object which have a small size when points of intersection of each arc with each transmitter-receiver as a center and a distance to a respective one of the detected objects as a radius, and each elliptic curve passing through a respective one of the detected objects with two of the transmitter-receivers as the center are not approximated roughly to one point and each of the elliptic curves are not the same.

4. An object detecting device according to claim 1, wherein:

the object determination element determines that there is only one detected object and has a large when points of intersection of each arc with each transmitter-receiver as a center and a distance to the detected object as a radius, and each elliptic curve passing through the detected object with two of the transmitter-receivers as the center are not approximated roughly to one point and each elliptic curve is the same.

5. An object detecting device according to claim 1, comprising:

a type determination element for determining a type of the detected object based on a time-varying characteristic of a reception strength of every reflected wave.

6. An object detecting device according to claim 5, wherein:

the type determination element determines the type of the detected object when it is determined that the detected object has a small size by the object determination element.

7. An object detecting device according to claim 6, wherein:

the type determination element determines that a human is included in the detected object when the reception strength of every reflected wave changes unstably with time.

8. An object detecting device according to claim 1, wherein:

the object determination element determines that there is more than one detected object and that the detected objects are each located in areas to be detected by only one of the transmitter-receivers when a reception distance of a reflected wave received by each transmitter-receiver of a radio wave transmitted by itself is computed and the reception distances of reflected waves of radio waves transmitted by other transmitter-receivers are not computed.