Sub-Nyquist Frequency and DOA Estimation With DOF Extension Arrayed MWC

We conducted frequency and direction of arrival estimations when more signals than sensors were present using a sub-Nyquist sampling system. We proposed a degrees of freedom (DOF) extension arrayed modulated wideband converter method based on a novel joint space-frequency sparse model, which can increase the DOF of the receiving array by appropriately increasing the sub-Nyquist sampling rate, was proposed. Our method does not require any special sparse array arrangement or an increase in the number of channels, thereby reducing cost and simplifying implementation. Coherent signals and source ambiguity were theoretically analyzed, and rigorous reconstruction conditions were provided for each case. Numerical results were provided to verify the effectiveness of the proposed method.