| 摘要 |
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. |
