DOA estimation using a sparse uniform linear array with two CW signals of co-prime frequencies

In this paper, we propose the use of a sparse uniform linear array to estimate the direction-of-arrival (DOA) of more sources than the number of sensors by exploiting two continuous wave signals whose frequencies satisfy a certain co-prime relationship. This extends the co-prime array and filter concept, which was developed in either the spectral or spatial domain, to a joint spatio-spectral domain, thereby achieving high flexibility in array structure design to meet the degrees-of-freedom and system complexity constraints. The DOA estimation is implemented in the difference co-array context to avoid spatial undersampling, and group sparsity based compressive sensing techniques are used to determine the direction of signal arrivals.