A weak target detection method for GPS based passive radar

In this paper the problem of disturbance cancellation in the surveillance channel of passive radar system, which exploits GPS transmitter as the illuminator, is addressed. The presence of direct-path interference (DPI) and multi-path interference (MPI) strongly affect the detection performance of passive radar. In the receiver system, the echo reflected from the target would be buried under the DPI and MPI. To solve this problem, the LS-CLEAN algorithm based on the lease-square method and CLEAN algorithm is proposed to suppress the interference. The DPI and MPI are removed iteratively by projecting received signals into the subspace which is orthogonal to the disturbance subspace. The effectiveness of the algorithm is demonstrated by simulation results.