Microwave Keyless Entry / Keyless Go System With Integrated Distance Measurement Feature

摘要

The proposed Keyless Entry / Keyless Go sensor is part of a car access- and drive permission system. It represents an alternative development to the existing manually remote controlled key lock system. The base station modules (BSM) of the new Keyless Entry / Go System recognise any person that carries an authorised transponder (tag) within a maximum distance of 10m around the car. Access is permitted after identification, coded data communication and distance measurement, respectively. A unique measurement setup makes it possible to determine the distance between the TAG (key) and the several BSM of the car highly accurate in the range of centimetres. When the door-handle is pulled, the distance has to be beyond a certain minimum to unlock the doors and to authorise the driver to enter the car. The system then recognises when the TRM is inside the car and consequently gives drive authorisation. When the driver simultaneously presses the brake pedal as well as a knob at the gearshift, the engine is started. For all the above-mentioned actions it is not necessary to insert a key into a lock, it is rather sufficient for the driver to carry the tag nearby himself, in his pocket or handbag. The tag (TRM) has the form and size of a conventional car key. While the driver is approaching the car, it is already possible to perform driver specific security and comfort adjustments, for example the positions of the rear-view- and the wing-mirrors, seat positions, air-conditioning of the interior, seat heating and the choice of the preferred radio station.