FM radar for mine detection - analyses beat frequencies from emitted and echo signals using contiguous narrow band filters and frequency multiplier

摘要

The system is used to locate energy supply pipes or wires or even dielectric mines, and operates without damaging the objects and provides safe operation for personnel. The radar may be carried by a vehicle and has an antenna (1) which is directed towards the ground. The antenna emits a microwave signal generated by an oscillator (4) which is frequency modulated by a low frequency oscillator (5). Part (6) of the emitted signal is reflected by the surface of the ground while a second part (7) is reflected by an antitank mine (8) to the receiving antenna (9). In the receiver (10), the reflected signals beat with the microwave oscillator frequency to indicate the distance from the ground and from the mine. Typ. the high frequency signal is of 2-4 GHz and is modulated by a triangular wave having a time period of 20ms, allowing an object to be localised at 0.5m with a resolution of 2.5cm.