US Patent 10012726 Rapid-chirps-FMCW radar

Method for determining distances and relative velocities of simultaneously located objects using an FMCW radar, in which the frequency of a transmission signal is modulated in the form of periodically recurring ramps, the transmission signal is mixed with a received signal to form an intermediate frequency signal and, for determining the distance and/or the relative velocity of the objects, the change in the phase of the intermediate frequency signal is evaluated from one ramp to the next characterized in that the modulation pattern includes at least two ramps, which differ only by a fixed frequency offset and follow one another in a certain time interval, and an unambiguous approximate value is calculated for the object distance on the basis of the phase difference φ1−φ2 of the intermediate frequency signals for these two ramps.