On Phase Measurement in FMCW Radar Systems

Unlike AM and PM systems, FM systems do not necessarily require the use of a dual I/Q receiver for unambiguous phase measurement. In this paper we describe this phenomenon in detail and work out the conditions when single-channel phase measurements can be used for the reliable measurement of the phase and the Doppler frequency of targets in FMCW radars systems. The developed theory is applied to surveillance and automotive radar systems to determine the velocity bounds for the unambiguous measurement of phase. The influence of phase noise in the same context is discussed. Results of coherent averaging on the data acquired using a single-channel radar system are presented to validate the theory.