High-Precision DOA Estimation Method Based on Synthetic Aperture Technique

The existing direction-of-arrival (DOA) estimation methods only utilize the current received signals, which are susceptible to noise. In this paper, a method for DOA estimation based on a motion platform is proposed to achieve high-precision DOA estimation by utilizing past and present signals. The concept of synthetic aperture is introduced to construct a linear DOA estimation model. A DOA fine-tuning method based on the linear model is proposed to eliminate the linear DOA variation, achieving a non-coherent accumulation of DOA estimations. Moreover, the baseband modulation and the phase modulation caused by the range history are compensated to achieve the coherent accumulation of all the DOA estimations. Simulation results show that the proposed method can significantly improve the DOA estimated accuracy at low signal-to-noise ratios (SNR).