The method involves generating a high frequency, linear frequency modulated signal (s) and directing it towards an object (7) whose distance (a) is to be measured. The signal reflected back from the object is received and a demodulated signal (y) derived from the transmitted (s) and received (r ) signals with a frequency corresp. to the difference between the signal frequencies, from which the distance is determined. At least one estimated signal (yhat) for the demodulated signal is formed using an acquired frequency and a variable phase. An estimation error (e)is obtained by comparison and the estimated signal phase varied adaptively to reduce the estimation error. The estimated signal frequency is corrected according to the time variation of the phase and the distance is derived from the corrected frequency (fhat).
