Oblique Projection DOA Estimation Algorithm Based on Spatial Polarization Characteristics

The high-resolution and high-accuracy performance of direction of arrival (DOA) estimation algorithms are adversely affected by multiple radiation sources with low SNR. These sources experience significant overlap in the time domain, aliasing in the frequency domain, and a dense distribution in the spatial domain. To address this issue, an innovative signal model for the polarization-sensitive array is proposed, which leverages the spatial polarization characteristics of the electromagnetic wave radiated by the transmitting antenna. Specifically, the proposed signal model focuses on the direction finding of the desired signal under active deception decoys with consistent co-polarization. The influence of one interference signal in the mixed signal can be eliminated by utilizing the time domain characteristics along with oblique projection technology based on this signal model. Subsequently, by using the co-polarization characteristics of the jamming signals, the influence of the other interference signals in the mixed signal can be effectively eliminated. The proposed algorithm estimates the closely spaced signals separately, which significantly reduces the influence of multiple radiation sources and enhances the resolution capability. Numerical simulations demonstrate that the proposed method has a high-resolution performance. Particularly, when employing an angular interval of 5°, the correct resolution probability of the proposed method increases by approximately 5% and 20% for scenarios involving two and three active jamming signals, respectively. The reliability of the proposed signal model and the effectiveness of the proposed algorithm are further validated by microwave anechoic chamber experiments and practical environmental tests.