Difference Co-Chirps-Based Non-Uniform PRF Automotive FMCW Radar

We propose an automotive radar system that transmits at non-uniform pulse repetition frequency (PRF) to achieve high-resolution range and Doppler estimation while transmitting sparsely along slow-time following the difference co-chirps schemes, e.g., coprime and nested chirps. At the receiver, the radar admits undersampled slow-time signals for Doppler estimation. In a single coherent processing interval (CPI), the missing Doppler samples along slow-time are interpolated via a Doppler covariance matrix that is constructed using fast-time samples. Our co-chirp joint range-Doppler estimation with Doppler de-aliasing (CoDDler) algorithm jointly estimates the range and Doppler. The Doppler spectrum obtained from the interpolated Doppler samples are utilized to de-aliase any false Doppler peaks in the sparse estimation. The proposed non-uniform PRF automotive radar provides the possibility for transmission coordination in a time division multiplexing fashion to avoid mutual interference by saving nearly 88% of time-on-target.