Securing method, interrogation unit and securing system for implementing the securing method

• US 20030117259A1
• Filed: 10/17/2002
• Published: 06/26/2003
• Est. Priority Date: 04/19/2000
• Status: Active Grant

• Current Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Original Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Inventors: Haas, Heinrich, Mueller, Karlheinz, Schuler, Rolf, Knepper, Udo
• Granted Patent: US 7,034,676 B2
• Time in Patent Office: Days
• US Class Current: 340/5.2
• CPC Class Codes: B60R 25/00 Fittings or systems for preventing or indicating unauthorised use or theft of vehicles locks for vehicles E05B77/00-E05B85/00
• CPC Class Codes: G07C 2009/00555 comprising means to detect or avoid relay attacks
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

In a securing method for securing an object against unauthorized use, an interrogation unit (1) is used to transmit an interrogation signal (s) and to test whether a response unit (2), which is to be carried by and on an authorized user, responds to the interrogation signal with a response signal (s) that contains as information a code authorized for desecuring a security device (3). If that is the case, the security device is desecured. The securing method is, however, ineffective, if unauthorized persons establish a radio link via relay stations between the interrogation unit (1) and the response unit (2), and via this radio link provide the code authorized for the desecuring to the interrogation unit (1) without being noticed by the authorized user. The new securing method shall prevent such interventions by unauthorized persons. The new securing method prevents the desecuring of the security device (3) if the signal transit time of a signal transmitted as the interrogation signal (s) and received as the response signal (t) by the interrogation unit (1) during a monitoring time interval (t4-t5) is greater than a prescribed value. Keyless security system for securing motor vehicles against unauthorized use.

Claims

1. Securing method for securing an object against unauthorized use, in which an interrogation signal (s) is transmitted by an interrogation unit (1) allocated to the object, and in which it is tested whether at least one response unit (2) allocated to a user responds to the interrogation signal (s) with a response signal (r), which contains as information a code authorized for desecuring a security device (3), characterized in that the desecuring of the security device (3) is prevented if a signal transit time of a signal that is transmitted as an interrogation signal (s) and received as a response signal (r) by the interrogation unit (1) during a monitoring time interval (t4-t5) is greater than a prescribed value.

2. Securing method according to claim 1, characterized in that the interrogation signal (s) contains a first data bit sequence (D1) as information and the response signal contains a second data bit sequence (D2) as information, whereby the data bits of the data bit sequences (D1, D2) are transmitted in bit cells of equal size, and the interrogation unit (1) simultaneously transmits data bits of the first data bit sequence (D1) and receives data bits of the second data bit sequence (D2) in the monitoring time interval (t4-t5).

3. Securing method according to claim 2, characterized in that the time spacing between a bit cell of the first data bit sequence (D1) transmitted by the interrogation unit (1) and a bit cell of the second data bit sequence (D2*) received by the interrogation unit is determined as the signal transit time.

4. Securing method according to claim 3, characterized in that the first data bit sequence (D1) is composed of an interrogation code and a filler code adjoining the interrogation code.

5. Securing method according to claim 4, characterized in that the response unit, for generating the second data bit sequence (D2) from the interrogation code, generates a response code (AO), which is encoded with simultaneously received bits of the filler code and transmitted.

6. Securing method according to claim 5, characterized in that the second data bit sequence (D2*) is decoded in the interrogation unit in a bitwise manner with simultaneously transmitted bits of the filler code, and in that the desecuring of the security device (3) is prevented if the result of the decoding deviates from an authorization code.

7. Securing method according to one of the claims 4 to 6, characterized in that the filler code is generated as a pseudo-random code.

8. Securing method according to one of the preceding claims, characterized in that the signal transmission between the interrogation unit (1) and the response unit (2) is carried out in the full duplex process.

9. Interrogation unit (1) for carrying out the securing method according to one of the preceding claims, with a transmit-receive unit (10) for transmitting the interrogation signal (s) and receiving the response signal (r) that is transmitted back by a response unit (2) in response to the interrogation signal (s) during the transmitting of the interrogation signal (s), and with an evaluating device (11) for evaluating the response signal (r) and desecuring a security device (3), whereby the evaluating device (11) comprises transit time evaluating means, which prevent a desecuring of the security device (3) if the signal transit time of a signal transmitted as the interrogation signal (s) and received as the response signal (r) by the interrogation unit is greater than a prescribed value.

10. Security system for securing an object against unauthorized use, with an interrogation unit (1) according to claim 9 allocated to the object, and at least one mobile response unit (2) that is allocated to a user and that cooperates with the interrogation unit (1).

11. Security system according to claim 10, characterized in that the at least one response unit (2) comprises at least one battery for the voltage supply.

12. Security system according to claim 10, characterized in that the at least one response unit (2) is embodied as a battery-less operated transponder, to which energy for the voltage supply can be provided inductively through the interrogation signal (s).

13. Use of the security system according to one of the claims 10 to 12 for securing a motor vehicle against unauthorized use.