Interference elimination method for FM-CW laser or microwave radar

摘要

The method involves using two FM transmitters to simultaneously transmit signals to a single measurement arrangement, providing an overlap of two output signals (s1,s2) and of a signal (11) reflected from an object with the output signals, and two separate reception signals (i1,i2) received by two detectors (9,10). The two transmitters are controlled to provide a frequency shift in the output signal, having different mean slope values. The received signals are multiplied, so as to provide a resulting signal which can be described as an addition of two terms. The first term oscillates according to the sum of intermediate frequencies of the received signals, providing an information representative of a distance, and the second term includes a disturbance corresponding to a movement of the object. The two terms are shifted w.r.t. each other in the frequency domain, allowing the second term to be eliminated.