Showing papers on "Intrusion detection system published in 1971"

Seismic signal intrusion detection classification system

Abstract: An intrusion detection system for detecting and classifying intrusions into a protected area by recognizing their characteristic patterns of seismic disturbances. A sensor produces an electrical signal representative of seismic disturbances created by an intrusion. Signals that surpass a predetermined level constitute an event. These signals are introduced to a histogram circuit that operates to determine the time between these events and to transmit a pulse to a classifier indicating each such time. The classifier generates a plurality of analogue signals each of which individually represents by its amplitude the sum of the pulses falling within a particular time between events pattern. Each pattern is characteristic of a particular type of intrusion such as aircraft, ground vehicle, human, nuisance, etc.

Intrusion detection false alarm reduction system

Abstract: False alarm reduction means for an intrusion detection system are disclosed wherein two optical transmitting systems with highly directive beams alternately illuminate adjacent but non-overlapping cross-sections. A signal processor indicates true target detection only when the target return from two or more successive pulses exceed a predetermined threshold which implies that the target is sufficiently large that it intersects both beams.

Near field target discrimination and intrusion detection system

Abstract: An intrusion detector circuit comprising multiple antennas to detect intrusion and yet eliminate signals attributable to near antenna movements which produce false alarms.

Personnel-vehicle intrusion detection system

Abstract: A perimeter intrusion detection system includes a pair of flexible tube members spaced apart and buried beneath the surface of the ground, coupled with transducer means to generate an electrical indication of changes in surface pressure attributable to personnel or vehicular movement across the surface of the ground. Electronic monitoring circuitry interprets these electrical indications generated by the transducers and generates electrical signals identifying the surface intrusion to be either that of personnel or vehicle. Electronic monitoring circuitry provides further discrimination of the vehicular intrusion by providing electrical indication of the direction, speed and weight of the intruding vehicle.