Sweep linearization of a microwave FMCW Doppler sensor by an ultrasonic reference

For a microwave FMCW Doppler sensor, a new linearization method is proposed using an ultrasonic FM reference signal. The received microwave signal is sampled with a sampling interval adapted to the phase intervals of the ultrasonic reference signal. With this linearized combined microwave/ultrasonic FMCW Doppler sensor, additionally to a high target detection reliability, a significantly improved resolution for range and velocity measurements and good multi-target selectivity are achieved.