The complex ambiguity function based on downsampled fourth-order statistics

Aiming at the problem of target detection in passive radar in correlated noise surroundings, we present a new estimation of the Complex ambiguity function based on Downsarnpled fourth-order statistics (CAF-DFOS) to improve the performances of the traditional Complex ambiguity function based on Second-order statistics (CAF-SOS) and the existing Complex ambiguity function based on Fourth-order statistics (CAF-FOS). Both the theory and the simulations show that in the aspect of Gaussian noise suppression, its performance is better than the CAF-SOS algorithm; in the aspect of estimate variance and frequency resolution, its performance is better than the CAF-FOS algorithm.