Patent ID: 6747545
Filing Date: 2004-06-08
Classification: G07C,H04W

Abstract:
An arrangement for a passive keyless entry system comprising:a base station arranged on an object to be secured against unauthorized access and a portable data carrier wherein the data carrier and the base station are configured to determine authorized access of the base station wherein the data carrier includes a plurality of orthogonally aligned antenna coils each being coupled to a LF receiver stage, and a UHF transmitter stage, wherein the base station includes a plurality of LF transmitter stages, an antenna coil associated with each LF transmitter stage a plurality of UHF receiver stages for receiving an UHF signal from the data carrier, wherein first position information of the relative position of the data carrier with respect to the antenna coils of the base station is gained from a measurement of the low-frequency, magnetic alternating fields transmitted by the LF transmitter stages of the base station to the data carrier, which information is transmitted in the UHF signal from the data carrier to the base station, wherein second position information of the relative position of the data carrier with respect to the UHF receiver stages of the base station is gained from a subsequent measurement of the UHF signal transmitted by the UHF transmitter stage of the data carrier to the base station, wherein a signal representing authorized access is generated by the base station when both position information components differ by less than a predetermined extent.