2D DOA and polarization estimation via synthetic nested dual-polarized array with scalable aperture in the presence of unknown nonuniform noise

For effectively enhancing the performance of two-dimensional direction-of-arrival and polarization estimation in practice, we propose a synthetic nested array with scalable aperture (SNASA), and then present a low-complexity estimation method, in unknown nonuniform noise environment. There is a systematic procedure to provide the numbers and positions of antennas for three subarrays of the SNASA, and then the estimation method based on one-dimensional sparse reconstruction can be used only once to achieve multi-parameter estimation. Compared with the existing nested polarization sensitive arrays (PSAs) with estimation methods, the proposed technique has some advantages: (a) The degrees of freedom of the SNASA is two times larger than that of the existing PSAs, due to the shared subarray of the former; (b) The physical aperture of the SNASA can be uniformly scaled while always keeping the ULA-based difference coarray, which enhances its flexibility applied for various platforms; (c) Both the nonuniform noise mitigation and the spatial information cooperated with polarized domain are automatically achieved by the block-sparse signal reconstruction, which avoids the extra complexity and the performance loss of the existing techniques for multi-parameter estimation case. The Cram & eacute;r-Rao bound and its existence condition are given in the presence of nonuniform noise. Numerical simulations are conducted to show the superior performance of the proposed technique.