Robust DOA Estimation for Passive Radar With Target Signals Mixed in the Reference Channel

In the frequency modulation (FM) radio-based passive radar system, the target signal mixed in the reference channel will have a negative impact on the target's own direction of arrival (DOA) estimation. To solve this problem, this letter proposes a robust DOA correction method. First, the digital beamforming (DBF) is used to obtain the reference signal. Second, the influence of the mixed target signal on the array steering vector is analyzed analytically. Finally, the DOA correction method is given. The effectiveness of the proposed method is validated using simulations and real-life data.