All Perimeter Intrusion Detection Systems are susceptible to false alarms and it is critical that all PID manufacturers continuously strive to lower these false alarm rates.  Microwave PID Systems have a low false alarm rate in comparison to other systems, however to make microwave a suitable PID system for a wide range of sites (over water, very close to fences, areas of dense foliage etc.) it is imperative to continuously strive to reduce false alarm rates.

False perimeter alarms create considerable additional effort and headache for operators to manage. Even a very low Nuisance Alarm Rate (NAR) has a severe effect on Perimeter security system performance.

The three attributes of a PID system (below) are investigated to analyse their potential to decrease false alarm rates caused by animals, weather and the movement of trees and foliage.   

• Operating Frequency
• Antenna
• Digital Signal Processing (DSP) of the data.

The outcome of this report is that a Microwave PID system operating at a frequency of 5.8GHz, with a planar antenna and using advanced Digital Signal Processing (DSP) techniques, provides a very attractive solution to reducing false alarm rates in perimeter security applications. For this reason microwave PIDS have the potential to be deployed in many more sites than previously thought suitable in the past; including port applications.