Two-stage DOA estimation method for low SNR signals in automotive radars

Abstract

In this study, the authors propose an effective two-stage direction-of-arrival (DOA) estimation method for low signal-to-noise (SNR) signals in automotive radar systems. When antenna elements in the array receive low SNR signals, the performance of subspace-based DOA estimation algorithms is degraded. Concerning this case, they propose an enhanced DOA estimation method that offers better angular resolution and estimation performance. The authors' proposed method is comprised of two stages. In the first stage, they roughly estimate the DOA using conventional subspace-based DOA estimation algorithms. Thereafter, the fine DOA estimation is performed in the next stage. The fine estimation includes a received signal calibration method using a priori information acquired from the previous stage. From simulation results, in terms of root mean square error and resolution probability, their proposed method exhibits a DOA estimation performance that is superior to that of the conventional method. Moreover, with actual measurement data, they verify that the proposed method can be applied to practical automotive radar systems.