Super-resolution direction finding method for mixed far-field and near-field signals based on gain-phase error array

Most of super-resolution direction finding methods always need precise array manifold. However, the amplitude gain and time delay of each channel are usually inequable, which results in the calculation performance degradation eventually. Therefore, this paper presents a new method of super-resolution direction finding for mixed far-field and near-field sources based on gain-phase error array. Direction of far-field signals is firstly acquired by transforming the space spectrum function. Then orthogonality of far-field signal subspace and noise subspace is employed to compute the gain and phase uncertainty for calibration. Finally, by removing the array error and part of far-field sources, directions and distances of near-field signals are obtained, meanwhile, their locations are also determined. The method estimates the signals by roots finding directly instead of spectrum searching, so as to speed up the calculation greatly with precision guaranteed as well.