Patent ID: 7385550

Claim:
A method for measuring distance and velocity at a plurality of objects using FMCW radar, the method comprising: cyclically repeating, in measuring cycles, measurements of the objects using at least two different frequency ramps, wherein in each of the measurements, a transmitted signal is mixed with a received signal to provide a mixed signal, and a spectrum of the mixed signal is recorded; performing a matching procedure, in which peaks that are in the spectra are recorded for various ramps and that belong to the same object are allocated to each other, and the distances and velocities of the objects are calculated from frequencies of the peaks; and performing a tracking procedure, in which the objects measured at various times are identified with one another based on consistency of their distance and velocity data; wherein: each of the measuring cycles includes not more than three measurements with different frequency ramps; for each plausible combination of two peaks, of which one was recorded during a first measurement and another of which was recorded during a second measurement of the same cycle, a distance and a velocity of one possible object represented by these peaks are calculated; an anticipated result of at least one further measurement is calculated from the distance and the velocity of the possible object; the possible object is discarded if at least one anticipated result does not agree with a measured result; and three measurements are performed in each measuring cycle, and the further measurement is a third measurement, in which a modulation duration of the frequency ramp is greater than for the first and second measurements.