DOA Estimation for Passive Radar Seeker Based on Offline Steering Vector

In order to counter active decoy system, passive radar seeker(PRS) must have the ability to simultaneously estimate the angles of multiple radiation sources with unknown polarization characteristics. In this letter, we propose a polarization sensitive direction of arrival(DOA) estimation algorithm based on off-line steering vector is proposed. Using the property that the intermediate frequency amplitude and phase output of the PRS receiver to an emitter located at a determined angle differs only by a complex constant from the real steering vector of the angle under high signal-to-noise ratio conditions. The intermediate frequency amplitude and phase data of the PRS receiver to the same radiation source at various angles are collected offline in an anechoic chamber, which is used as the steering vector table for real-time calculation of spatial spectrum, and then the DOA of the main source and decoys with arbitrary polarization are estimated simultaneously. The static tests in anechoic chamber indicate that the proposed method can positively estimate the angles of multiple electromagnetic wave signals arriving simultaneously with different polarizations.