Novel algorithms for FMCW range finding with microwaves

Abstract

The output of a conventional FMCW ranging measurement is the real-part of the free-space transfer function. However, the missing imaginary part leads to an artificial but non-negligible measurement error, when employing a Fourier transform for distance evaluation. Novel algorithms for processing the FMCW measurement raw data are described, allowing complete suppression of the aforementioned image-error. Measurement uncertainties of /spl plusmn/0.2 mm have been achieved, performed in the frequency range from 8.5 up to 10.4 GHz. A considerable improvement is obtained even in comparison to entirely complex measurements.