A High-efficient and High-accurate Distance Measurement Technique Based on Phase Differentiation and Accumulation with FMCW radars

In the Frequency-Modulated Continuous-Wave (FMCW) radar, high-accurate distance measurement based on frequency estimation suffers from limited frequency resolution and large compute resource consumption. In this paper, a Phase Differentiation and Accumulation (PDA) technique is proposed for high-efficient and frequency resolution free distance measurement with FMCW radar. It works by accumulating center phase variation from a uniformly segmented chirp. The coarse frequency estimated from the segmented chirp signal is used to resolve the phase ambiguity. Theory analysis shows that by properly choosing the segmentation number as 3, the distance estimation variance with the proposed technique can be close to the Cramer-Rao Lower Bound (CRLB) of the conventional frequency estimation method, and the time complexity of the proposed technique is only O(Nlog(N/3)), which is even smaller than the non-zero-padded FFTâ€™s time complexity. Simulations and experiments show that when achieving similar accuracy, the proposed technique saves over 500 times compute resources.