EVALUATING UNIT FOR A DEVICE FOR DETECTING OBJECTS, IN PARTICULAR FOR MONITORING THE INTERIOR OF A MOTOR VEHICLE, AS WELL AS A DEVICE FOR DETECTING OBJECTS HAVING SUCH AN EVALUATING UNIT AND A METHOD FOR CONTROLLING SUCH A DEVICE

• US 6,429,774 B1
• Filed: 12/09/1999
• Issued: 08/06/2002
• Est. Priority Date: 06/09/1997
• Status: Expired due to Fees

• Current Assignee: Continental Automotive GmbH (Continental AG), Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.), Siemens AG
• Inventors: Schmid, Reinhard, Bözen, Hendrik, Pietsch, Arnulf, Swart, Marten, Hamperl, Reinhard
• Primary Examiner(s): POPE, DARYL C
• Application Number:
  US09/456,714
• Time in Patent Office: 971 Days
• Field of Search: 340/426, 340/438, 340/506, 340/511, 340/514, 340/545.3, 340/552, 340/554, 340/567, 340/825.58
• US Class Current: 340/506
• CPC Class Codes: B60R 21/01534 using electromagneticwaves, e.g. infrared
• CPC Class Codes: B60R 21/01556 Child-seat detection systems
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 7/4004 of parts of a radar system
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values

Abstract

A demodulator of an evaluating unit for a device for detecting objects derives a useful signal from a supplied input signal with the aid of a carrier signal. The demodulator further derives a test signal with the aid of a modulated carrier signal. An evaluator detects as a function of the useful signal whether an object is being detected and, as a function of the test signal the functionality of the device.

Claims

1. An evaluating unit for a device for detecting objects, comprising:

a demodulator receiving an input signal and a carrier signal and deriving a useful signal from the input signal with the aid of the carrier signal, said demodulator generating a modulated carrier signal modulated with an auxiliary signal and deriving a test signal from the input signal with the aid of the modulated carrier signal; and

an evaluator receiving the useful signal and the test signal, said evaluator detects a presence of an object by evaluating the useful signal and detects a malfunction by evaluating the test signal.

2. The evaluating unit according to claim 1, wherein said evaluator detects the object when the useful signal includes an object-specific signal.

3. The evaluating unit according to claim 1, wherein said evaluator detects the malfunction when the test signal does not include the auxiliary signal.

4. The evaluating unit according to claim 1, wherein said demodulator has a multiplier for multiplying the input signal by the carrier signal, and for multiplying the input signal by the modulated carrier signal.

5. The evaluating unit according to claim 4, wherein said demodulator includes a low-pass filter connected downstream of said multiplier.

6. The evaluating unit according to claim 1, wherein said demodulator demodulates a phase-modulated input signal.

7. The evaluating unit according to claim 1, wherein said demodulator demodulates an amplitude-modulated input signal.

8. The evaluating unit according to claim 6, wherein the carrier signal is a high-frequency carrier signal having a phase angle that can be changed by a fixed absolute value.

9. The evaluating unit according to claim 1, wherein the object to be detected is an occupant of a vehicle.

10. The evaluating unit according to claim 1, wherein the object to be detected is a child seat disposed on a vehicle seat.

11. The evaluating unit according to claim 1, wherein the object to be detected is disposed in an interior of a motor vehicle.

12. A device for detecting objects, comprising:

a receiving antenna receiving an input signal; and

an evaluating unit receiving the input signal from said receiving antenna and generating a carrier signal, said evaluating unit, including;

a demodulator receiving the input signal and the carrier signal and deriving a useful signal from the input signal with the aid of the carrier signal, said demodulator generating a modulated carrier signal modulated with an auxiliary signal and deriving a test signal from the input signal with the aid of the modulated carrier signal; and

an evaluator receiving the useful signal and the test signal, said evaluator detects a presence of an object by evaluating the useful signal and detects a malfunction by evaluating the test signal.

13. The device according to claim 12, including a transmitting antenna emitting an electromagnetic measuring field coupled magnetically to said receiving antenna.

14. The device according to claim 12, wherein said evaluation unit is to be disposed in an interior of a motor vehicle.

15. A method for controlling a device for detecting objects including the objects disposed in an interior of a motor vehicle, which comprises:

emitting a carrier signal via a transmitting antenna;

modulating the carrier signal with an object-specific signal from an object to be detected resulting in an modulated carrier signal received as an input signal by a receiving antenna coupled to the transmitting antenna;

demodulating the input signal with the carrier signal, and the object being derived to be detected when the input signal demodulated with the carrier signal includes the object-specific signal; and

demodulating the input signal with a further modulated carrier signal modulated with an auxiliary signal if the input signal demodulated with the carrier signal does not include the object-specific signal, and a malfunction being determined if the input signal demodulated with the further modulated carrier signal does not include the auxiliary signal.