Automotive radar device

• US 20070085728A1
• Filed: 04/07/2006
• Published: 04/19/2007
• Est. Priority Date: 10/14/2005
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Matsuoka, Katsuji
• Granted Patent: US 7,486,222 B2
• Time in Patent Office: Days
• US Class Current: 342/70
• CPC Class Codes: G01S 13/931 of land vehicles
• 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 7/4078 involving an integrated reference reflector or reference transponder

Abstract

A automotive radar device is provided that can securely detect dirt adhering to the surface of a vehicle-side radome irrespective of the positional relation between the vehicle-side radome and a radar. The automotive radar device has a radio-type radar housed in a vehicle-side radome installed on a vehicle, the radar-type radar including a transmitting unit and a receiving unit. The automotive radar device sends and receives radio waves from the radar through the vehicle-side radome and measures distance and relative velocity with respect to a subject. The automotive radar device includes a guiding unit that is arranged between the vehicle-side radome and the radar and that guides a reflected wave from adhering matter on a surface of the vehicle-side radome to the receiving unit of the radar, and an adhering matter judging unit that judges the existence/non-existence of the adhering matter on the surface of the vehicle-side radome on the basis of signal level of the reflected wave received by the guiding unit.

Claims

1. A automotive radar device having a radio-type radar housed in a vehicle-side radome installed on a vehicle, the radar-type radar including a transmitting unit and a receiving unit, the automotive radar device sending and receiving radio waves from the radar through the vehicle-side radome and measuring distance and relative velocity with respect to a subject, the automotive radar device comprising:

a guiding unit that is arranged between the vehicle-side radome and the radar and that guides a reflected wave from adhering matter on a surface of the vehicle-side radome to the receiving unit of the radar; and

an adhering matter judging unit that judges the existence/non-existence of the adhering matter on the surface of the vehicle-side radome on the basis of signal level of the reflected wave received by the guiding unit.

2. The automotive radar device as claimed in claim 1, wherein the guiding unit guides only a reflected wave in a specific beam direction to the receiving unit.

3. The automotive radar device as claimed in claim 1, wherein the adhering matter judging unit has a level change detecting unit that compares the signal level of the reflected wave reflected by the guiding unit with a predetermined level and that detects that there is a level change if absolute value of difference in the level is equal to or larger than a predetermined value, and wherein if it is detected by the level change detecting unit that there is a level change, the adhering matter judging unit determines that adhering matter exists on the surface of the vehicle-side radome.

4. The automotive radar device as claimed in claim 3, wherein the predetermined level compared with the signal level of the reflected wave is a learned value of reflection level up to the previous time.

5. The automotive radar device as claimed in claim 3, wherein the adhering matter judging unit determines that adhering matter exists on the surface of the vehicle-side radome if a state where a level change is judged to exist by the level change detecting unit continues for a predetermined period of time.

6. The automotive radar device as claimed in claim 2, wherein the adhering matter judging unit judges the existence/non-existence of adhering matter on the surface of the vehicle-side radome on the basis of the signal level of the reflected wave in the specific beam direction and in the other beam direction.

7. The automotive radar device as claimed in claim 6, wherein the adhering matter judging unit determines that adhering matter exists on the surface of the vehicle-side radome if absolute value of difference in the signal level of the reflected wave between the specific beam direction and the other beam direction is equal to or larger than a predetermined value.

8. The automotive radar device as claimed in claim 6, wherein the adhering matter judging unit determines that adhering matter exists on the surface of the vehicle-side radome if a state where absolute value of difference in the signal level of the reflected wave between the specific beam direction and the other beam direction is equal to or larger than a predetermined value continues for a predetermined period of time.

9. The automotive radar device as claimed in claim 1, wherein the guiding unit reflects the reflected wave from the adhering matter on the surface of the vehicle-side radome to a direction where the receiving unit exists.

10. The automotive radar device as claimed in claim 1, wherein the guiding unit reflects the reflected wave from the adhering matter on the surface of the vehicle-side radome to a direction where the receiving unit exists so that the reflected wave becomes parallel to directional direction of a receiving antenna.

11. The automotive radar device as claimed in claim 9, wherein the guiding unit is a reflecting mirror.

12. The automotive radar device as claimed in claim 9, wherein the guiding unit is a flat array antenna having total reflection at its feeding point.

13. The automotive radar device as claimed in claim 9, wherein the guiding unit is a flat array antenna in which a feeding point can be switched between total reflection and terminal by a switch.

14. The automotive radar device as claimed in claim 9, wherein the guiding unit is a reflector array.

15. The automotive radar device as claimed in claim 1, wherein the guiding unit refracts the reflected wave from the adhering matter on the surface of the vehicle-side radome into a direction where the receiving unit exists.

16. The automotive radar device as claimed in claim 1, wherein the guiding unit refracts the reflected wave from the adhering matter on the surface of the vehicle-side radome into a direction where the receiving unit exists so that the reflected wave becomes parallel to directional direction of a receiving antenna.

17. The automotive radar device as claimed in claim 15, wherein the guiding unit is a dielectric lens.

18. The automotive radar device as claimed in claim 1, wherein the guiding unit is arranged on the opposite sides of a transmission wave transmitted by the transmitting unit and guides the reflected wave from the adhering matter on the surface of the vehicle-side radome into a direction where the receiving unit exists.

19. The automotive radar device as claimed in claim 1, wherein the guiding unit reflects the reflected wave from the adhering matter on the surface of the vehicle-side radome to its incoming direction.

20. The automotive radar device as claimed in claim 19, wherein the guiding unit is a reflecting mirror.

21. The automotive radar device as claimed in claim 19, wherein the guiding unit is a single corner reflector or plural corner reflectors.

22. The automotive radar device as claimed in claim 19, wherein the guiding unit is a flat array antenna having total reflection at its feeding point.

23. The automotive radar device as claimed in claim 19, wherein the guiding unit is a flat array antenna in which a feeding point can be switched between total reflection and terminal by a switch.

24. The automotive radar device as claimed in claim 19, wherein the guiding unit is a reflector array.

25. The automotive radar device as claimed in claim 1, wherein the guiding unit guides the reflected wave from the adhering matter on the surface of the vehicle-side radome to a direction where the receiving unit exists by using a waveguide.

26. The automotive radar device as claimed in claim 1, wherein the guiding unit guides the reflected wave from the adhering matter on the surface of the vehicle-side radome to a direction where the receiving unit exists by using a dielectric waveguide.

27. The automotive radar device as claimed in claim 1, wherein the guiding unit is integrally constructed with the vehicle-side radome.

28. The automotive radar device as claimed in claim 1, wherein the guiding unit is integrally constructed with the radar.

29. The automotive radar device as claimed in claim 1, wherein the guiding unit is integrally constructed with the vehicle-side radome and the radar.