Patent ID: 6788247
Filing Date: 2004-09-07
Classification: G01S

Abstract:
A distance and speed measuring method in which a relative distance and a relative speed of a target are measured based on a beat signal comprising a transmission signal and a reception signal of a continuous wave radar, which is frequency modulated by a triangular wave,said method being characterized by comprising: a present measurement stage in which beat frequencies are extracted from the beat signal in an up phase (modulation frequency rise period) and in a down phase (modulation frequency fall period), and a frequency pair of beat frequencies corresponding to the target is selected among the extracted frequencies, the relative distance and the relative speed of the target being obtained based on the thus selected frequency pair as observed values, from which a relative distance, a relative speed and a beat frequency of the target are obtained as estimated values at the next observation time; and next and following measurement stages in which relative distances and relative speeds of the target at the next and following observation times are measured by using only beat frequencies in either one of the up phase and the down phase.