Location independent intrusion detection system

A location-independent intrusion detection system, comprising:

• passive infrared radiation (PIR) intrusion detection means for sensing the infrared radiation of an intruder, said PIR detection means comprising a substantially hemispherically shaped fresnel lens having a plurality of fresnel lens segments, each lens segment for focusing infrared radiation from a field of view, with the plurality of fresnel lens segments focusing infrared radiation from a plurality of spaced apart fields of view from a substantially conically shaped volume of space, with the conically shaped volume of space having an axis perpendicular to the plane of the PIR intrusion detection means, and the volume of space symmetrical about the axis;
• and
• microwave transceiver means comprising microwave generating means for generating microwave radiation, a bent monopole antenna for radiating the microwave radiation generated by the microwave generating means into a substantially balloon shaped symmetrical volume of space having an axis, substantially perpendicular to the plane of the microwave transceiver means;
• wherein the balloon shaped volume of space of said microwave transceiver means substantially coincides with the conically shaped volume of space of the PIR intrusion detection means.