Security system
First Claim
1. 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.
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Accused Products
Abstract
Vehicle security systems comprise at least one addressable transponder for communication with at least one base station. Each transponder and base station comprises a steerable directional antenna having an antenna azimuth sensor. Transponder and base station antenna azimuths assist in locating a vehicle carrying a transponder and allow near real-time estimation of vehicle heading. Base station networks facilitate location, tracking and/or interception of vehicles within a network geographic area. Use of multiple effective transmission ranges for transponders and/or base stations improves the accuracy of vehicle location.
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Citations
20 Claims
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1. A vehicle security system comprising
at 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of monitoring a vehicle on which an addressable transponder is mounted, the method comprising
transmitting a first signal from a base station to said addressable transponder via said steerable directional base station antenna, said first signal encoding an address for said transponder, and said base station antenna having been steered to a base station antenna azimuth; -
receiving said first signal at said transponder via a steerable directional transponder antenna, said transponder antenna having been steered to a transponder antenna azimuth;
transmitting a second signal from said transponder to said base station for acknowledging receipt of said first signal at said transponder, said second signal encoding said transponder address and said transponder antenna azimuth;
receiving said second signal at said base station;
decoding said second signal to obtain a received-decoded transponder address and to obtain a received-decoded transponder antenna azimuth;
subtracting said received-decoded transponder antenna azimuth from said base station antenna azimuth to form an antenna azimuth difference;
adding 180 degrees to said antenna azimuth difference to estimate said vehicle heading; and
associating said received-decoded transponder address with said estimated vehicle heading to monitor said vehicle. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method for monitoring a vehicle on which an addressable transponder is mounted, the method comprising
transmitting a signal from said addressable transponder to a base station to via a steerable directional transponder antenna, said transponder antenna having been steered to a transponder antenna azimuth relative to said vehicle, and said signal encoding at least an address of said transponder and said transponder antenna azimuth; -
receiving said transmitted signal at said base station via a steerable directional base station antenna, said base station antenna having been steered to a base station antenna azimuth;
decoding said received signal to obtain at least said transponder address and said transponder antenna azimuth;
subtracting said transponder antenna azimuth from said base station antenna azimuth to form an antenna azimuth difference;
adding 180 degrees to said antenna azimuth difference to estimate said vehicle heading relative to said base station; and
associating said transponder address with at least said vehicle heading for monitoring said vehicle. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification