Method for measuring the range and the relative speed of a body with reference to a periodically frequency modulated continuous wave radar

摘要

The method of measuring relative speed and distance involves using radar waves which vary periodically in frequency. The distance and speed are determined by combining two beat frequencies which are extracted from the mixture of emitted and reflected signals. These are obtained during the rising and falling portions of the modulation. The distance and speed are calculated at every half period using the beat frequencies of the two immediately previous values. Envelopes of the values obtained are generated. When the envelopes cross then a change in direction of variation is noted.