Estimating the directions of arrival of narrow band signals using Spatial Tuned Filter

In this paper, we present a novel way of estimating the direction of arrival (DOA) of narrow band signals using beam-steering technique. The coefficients for steering the beam are derived using a second order autoregressive (AR) narrow-band filter. Mapping an AR(2) process into spatial domain is not viable and hence, an equivalent FIR filter is obtained, which represents a Uniform Linear Array (ULA). Closed form solution for this FIR filter coefficients is derived. Beam-steering is performed using these coefficients to obtain the DOA. Estimating the DOA is viewed as a min-max problem. The minimization is performed using simple gold-section univariate minimization technique without gradients. Results are presented in this paper for single and multiple emitters. They show that this approach gives accurate results under different signal-to-noise ratio (SNR) conditions.