VEHICLE ANTITHEFT DEVICE Russian patent published in 2002 - IPC

FIELD: alarm systems. SUBSTANCE: invention is designed to prevent unauthorized use of vehicles. According to invention, the following devices are mounted on vehicle: supply source, current-limiting resistor, light-emitting diode, sealed contact reed relay, intermittent signal generator, electromagnetic relay, remote control switch, master oscillator, phase key and transmitter coupled with transmitting antenna. Receiving station has one metering and two direction finding channels including receiving antennas, heterodynes, mixers, search unit, first and second intermediate frequency amplifiers, frequency doubler, frequency meters, spectrum width meters, comparator unit, threshold unit, delay line, keys, frequency detector, phase detectors, trigger, recorder units, multipliers, narrow-band filters and computing unit. Device provides both transmission of alarm signal by radio channel in case of hijacking and taking of its azimuth and makes it possible to determine, by passive phase method, distance to vehicle, its range rate and azimuth rate. EFFECT: improved reliability of protection. 4 dwg