A Doppler focusing approach for sub-Nyquist radar

Abstract

We investigate the problem of a monostatic radar transceiver trying to detect a sparse target scene. Several past works employ compressed sensing (CS) algorithms to this type of problem, but either do not address sample rate reduction, impose constraints on the radar transmitter, or propose CS recovery methods with prohibitive dictionary size. Here, using the Xampling framework, we describe a sub-Nyquist sampling approach which overcomes the shortcomings of previous methods. Xampling allows reducing the number of samples needed to accurately represent the signal, directly in the analog-to-digital conversion process. After sampling, the entire digital recovery process is performed on the low rate samples without having to return to the Nyquist rate. With our recovery method we are able to obtain good detection performance even at SNRs as low as -25dB.