Optimized Array Geometry for 2D-DOA Estimation Using a Time-Multiplexed Co-Array Approach

This paper investigates optimized array geometries for direction of arrival (DOA) estimation of impinging electromagnetic signals using a receiver system that employs fewer receiver channels than antenna elements. As in previous work [1], [2], co-array and spatial smoothing techniques are used to reconstruct an appropriate received signal covariance matrix. By this switched co-array approach, it is possible to find the directions for number of sources even equal to the number of receiver channels, contrary to conventional methods. The considered 3-channel receiver system consists of a specifically arranged (co-)array antenna divided into a 6-element uniform circular prototype array coupled through a switch to one receiver channel, and 2 directly connected reference antenna elements, respectively. Here, the reference element positions are optimized to achieve better direction finding (DF) accuracy. Simulation results show that optimized antenna geometries for time-multiplexed (switched) DOA estimation can be found for a selected set of DOAs which is verified by simulated measurements.