SEISMIC-MAGNETOMETRIC DEVICE FOR INTRUDER ALARM Russian patent published in 2003 - IPC

FIELD: intruder alarm facilities. SUBSTANCE: device that depends for its operation on combined seismic and magnetometric principle of detecting intruders crossing border line being guarded has sensing element in the form of three cable segments of specific design buried in ground on same plane and equally spaced apart along line being guarded; external and shielding conductors of each segment form three series-connected distributed seismic transducers of K internal conductors of first and third segments(cable has N conductors); 2K conductors of second segment form U-shaped magnetometric induction transducer; series-connected (N - K) internal conductors of first and third segments form U-shaped magnetometric transducer; seismic and magnetic signals arriving from each transducer are amplified, filtered off, detected, and processed in device so as to eliminate noise caused by invader and to separate useful signals recognized by characteristic features with the result that device yields outgoing alarm or incoming alarm signals; noise monitoring provides for serviceability check of device. EFFECT: enhanced operational and tactical reliability of device. 6 cl, 17 dwg, 2 tbl