Patent ID: 6819245
Filing Date: 2004-11-16
Classification: B60R

Abstract:
A vehicle security system comprisingat least one addressable transponder for receiving security information addressed to it from at least one base station, and for transmitting security information to at least one said base station, each said transponder comprising an addressable transponder receiver; an addressable transponder transmitter connected to said transponder receiver; and a transponder antenna connected to said transponder receiver and said transponder transmitter; and at least one said base station for receiving security information transmitted from at least one said transponder, for transmitting security information addressed to at least one said transponder, and for communicating security information with at least one operator, each said base station comprising a base station receiver; a base station transmitter connected to said base station receiver; a base station antenna connected to said base station receiver and said base station transmitter; and an operator interface connected to said base station receiver and said base station transmitter for bidirectional communication with at least one operator of security information received at and security information transmitted by each said base station; and wherein each said transponder antenna comprises a steerable directional antenna and a steerable directional antenna azimuth sensor for providing security information comprising a transponder antenna azimuth indicative of each azimuth to which said steerable directional transponder antenna is steered; and wherein each said base station antenna comprises a steerable directional antenna and a steerable directional antenna azimuth sensor for providing security information comprising a base station antenna azimuth indicative of each azimuth to which said steerable directional base station antenna is steered; and wherein each said transponder receiver comprises a discriminator for rejecting base station transmissions not addressed to said transponder, together with a decoder to decode security information encoded in base station transmissions addressed to said transponder; and wherein each said transponder transmitter comprises an encoder for encoding security information comprising an address for said transponder and said transponder antenna azimuth in each transmission from said transponder; and wherein each said base station receiver comprises a decoder to decode security information encoded in transmissions received from at least one said transponder; and wherein each said base station transmitter comprises an encoder for encoding security information comprising at least one transponder address in each transmission from said base station to at least one addressable transponder.