Direction-of-arrival (DOA) estimation using a single snapshot of voltages induced in a real array operating in any environment

This paper investigates an electromagnetic preprocessing technique that transforms the voltages that are induced in a nonuniformly spaced array containing real antenna elements to a set of voltages that will be produced in a uniform linear virtual array (ULVA) containing omnidirectional isotropic point radiators. The objective here is that, in the processing methodology, we would like to include various electromagnetic effects like mutual coupling between the antenna elements, the presence of near-field scatterers, and the platform effects on which the antenna array is mounted. The preprocessing is carried out using a least squares method, which generates a transformation matrix for the set of induced voltages in the real array. This transformation matrix, when applied to the actual measured voltages, yields as equivalent set of voltages that will be induced in the ULVA. Then, a direct data domain superresolution technique like the matrix pencil method is applied to the processed voltages to yield the DOA for the various signals of interest. Numerical results are presented to illustrate the efficiency and accuracy of this method.