For the microwave level meter based on the FM-CW radar, we analyze the spec
trum correlation of beat signals and propose a measurement algorithm using
the fact that there exists a peak in the spectrum correlation of beat signa
ls when range difference is sufficiently small. This algorithm can compensa
te the nonlinear effect of VCO frequency sweep, making it possible to deter
mine the range difference in a precise manner even using a practical VCO. W
e present some experimental results to show the validity of this algorithm.