A closed-form formula for RSSI-based DoA estimation with Switched Beam Antennas

In this paper we present a novel Direction of Arrival (DoA) estimator for Switched Beam Antennas (SBA). The proposed approach is based on the best analytic approximation of the power pattern ratio between adjacent beams. Under quite general assumptions, the proposed approach resolves to the solution of a quadratic equation. Compared to conventional estimators, the precision of the proposed approach is competitive, permitting a cost-effective solution for low complexity implementation. Computer simulations and experimental verifications in a anechoic setup confirm the proposed approach when operating with a circular polarized SBA and the received signal strength data collected with a low-cost commercial transceiver. A mean error of 1.1° with a standard deviation of 1.6° is experimentally observed when the SBA communicates with a co-polarized target at the range of 2 meters. Only 5% of the observation angle is affected by an error exceeding 5°.