Anti-theft protection system for a motor vehicle, and a method for operating an anti-theft protection system

• US 6,809,629 B2
• Filed: 11/30/2000
• Issued: 10/26/2004
• Est. Priority Date: 11/30/1999
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Heide, Patric, Vossiek, Martin, Piesch, Wolfgang, Roskosch, Richard, Ilg, Johannes, Hofbeck, Klause
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): Nguyen, Nam V
• Application Number:
  US09/725,949
• Publication Number:
  US 20010005170A1
• Time in Patent Office: 1,426 Days
• Field of Search: 340/5.61, 340/5.63, 340/5.64, 340/5.65, 340/5.7, 340/5.72, 340/825.69, 340/825.72, 342/42, 342/457
• US Class Current: 340/5.61
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G07C 2209/63 Comprising locating means for detecting the position of the data carrier, i.e. within the vehicle or within a certain distance from the vehicle
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

Anti-theft protection system for a motor vehicle, and a method for operating an anti-theft protection system. The anti-theft protection system has a transmitting and receiving unit in the motor vehicle, which transmits radar signals and then waits for echo signals. A code transmitter, which receives a radar signal, modulates this signal and sends it back. An evaluation unit analyses all the received echo signals firstly for authorization of the code transmitter and secondly in order to determine the relative interior/exterior position of the code transmitter with respect to the motor vehicle.

Claims

1. An anti-theft protection system for a motor vehicle, the anti-theft protection system comprising:

a transmitting and receiving unit adapted to be arranged on the motor vehicle, the transmitting and receiving unit transmitting a transmitted signal with several carrier frequencies modulated within a frequency band;

a code transmitter adapted to be portable with respect to the motor vehicle, the code transmitter transmitting a coded and modulated echo signal at least in response to receiving the transmitted signal; and

an evaluation unit evaluating the echo signal to determine a position of the code transmitter based on at least one of the carrier frequencies reflected in an echo profile of the echo signal and determining authorization of the code transmitter by demodulating and decoding the echo signal.

2. The anti-theft protection system as claimed in claim 1, wherein the transmitting and receiving unit is adapted to be arranged on at least one of an internal mirror and one or more doors of the motor vehicle.

3. The anti-theft protection system as claimed in claim 1, further comprising:

a plurality of the transmitting and receiving units adapted to be distributed on the motor vehicle, each of the plurality of the transmitting and receiving units transmit the transmitted signal and receive the echo signal; and

wherein the evaluation unit evaluates the echo signal received by each of the plurality of the transmitting and receiving units to determine the distance between the code transmitter and the transmitting and receiving unit.

4. The anti-theft protection system as claimed in claim 1, wherein the evaluation unit comprises a memory storing echo profiles as reference patterns.

5. The anti-theft protection system as claimed in claim 1, wherein the evaluation unit comprises a neural network evaluating the echo profiles.

6. The anti-theft system of claim 1, wherein the position of the code transmitter to the transmitting and receiving unit is measured using an amplitude of at least one of the carrier frequencies.

7. The anti-theft system of claim 1, wherein the position of the code transmitter to the transmitting and receiving unit is measured using a phase of at least one of the carrier frequencies.

8. The anti-theft system of claim 1, wherein the position of the code transmitter to the transmitting and receiving unit is measured using a frequency difference of at least one of the carrier frequencies.

9. A method for operating an anti-theft protection system for a motor vehicle, the method comprising:

transmitting a broadband modulated transmitted signal from a transmitting and receiving unit adapted to be arranged on the motor vehicle;

receiving a coded and modulated echo signal transmitted from a code transmitter adapted to be portable with respect to the motor vehicle; and

evaluating the echo signals in an evaluation unit adapted to be arranged on the motor vehicle, the evaluating including determining a position of the code transmitter based on a reflected frequency in an echo profile of the echo signal and determining authorization of the code transmitter by demodulating and decoding the echo signal.

10. The method as claimed in claim 9, wherein a plurality of the transmitting and receiving units are adapted to be distributed on the motor vehicle, and wherein the transmitting comprises a respective plurality of the transmitted signals and the evaluating comprises a plurality of the echo signals.

11. The method as claimed in claim 9, further comprising:

associating the echo signals with the position of the code transmitter being one or internal with respect to the motor vehicle and external with respect to the motor vehicle.

12. The method as claimed in claim 9, wherein the transmitting comprises at least one of a microwave signal and a radar signal being transmitted at a frequency greater than 1 GHz.

13. The method of claim 9, wherein the position of the code transmitter to the transmitting and receiving unit is measured using an amplitude of the reflected frequency.

14. The method of claim 9, wherein the position of the code transmitter to the transmitting and receiving unit is measured using a phase of the reflected frequency.

15. The method of claim 9, wherein the position of the code transmitter to the transmitting and receiving unit is measured using a frequency difference of the reflected frequency.