Intrusion detection system having look-up sensor instrumentation for intrusion range and altitude measurements

摘要

Range and elevation measurement ambiguities in upward looking intruder detection systems are eliminated by look-up sensor instrumentation that utilizes monostatic and bistatic radar principles. Intruder detection systems that have the capability of monitoring the air space over the perimeter of an area to be protected and that employ radar ranging techniques and guided wave sensor generate only limited or ambiguous intrusion event information. That is, the r.f. signals that are transmitted and received travel from the transmitter-receiver-processor location through the sensor, up to the intrusion and back through the same path. The data developed is thus the same for high altitude close range intrusions as it is for low altitude distant intrusions. This ambiguity is eliminated by utilizing a transmitter and receiver at one end of the upward looking sensor and a second receiver at the other end. The transmitter and its associated receiver comprises a monostatic radar and the transmitter and the other receiver comprises a bistatic radar. The conventional monostatic radar measures total distance from the transmitter to an intrusion. The bistatic radar measures intrusion altitude only. The two radar outputs are differenced by a processor to determine range.