Nonlinear Array Processing via a Nested Array: Theory and Experimental Evaluation

Array processing by means of using the difference coarray as a virtual uniform linear array (VULA) has become a popular approach, mainly due to the claim of obtaining $\mathcal{O}(N^{2})$ degrees of freedom (DOF) from a $N$ element sparse array. In this work we seek to understand if and how this type of nonlinear array processing (NAP) approach could be used for direction of arrival (DOA) estimation and adaptive beamforming from the perspective of a pulsed radar system. More specifically, our study seeks to validate some of the theoretical aspects and challenges of NAP through an experimental emulation of the receive side of a monostatic 6 element nested array radar.