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AssigneeConti Temic microelectronic GmbH
InventorsHeinrich Haas, Udo Knepper, Karlheinz Mueller, Rolf Schuler
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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.
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.
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.
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.
Dependencies are inferred from the claim text.