High Performance Direction Finding Algorithm Based on Phase Locked Loop

Abstract

Using Phase Locked Loop based single channel Direction Finding (DF) system to estimate the bearing angle or the coordinates of an incoming radio signal(s) has much more advantages than multiple receiver system does in many practical scenarios such as mobile communication. This method utilizes a bank of Phase Locked Loops (PLLs) to calculate the differential phase of signal received by an M-element uniform circular antenna array with a commutative switch followed by single channel Software Defined Radio (SDR) receiver. One important factor when using conventional phase locked loop is the requirement of the small convergence rate of the algorithm compared to the switching cycle. In order to achieve small convergence rate, we propose a method for DOA estimation with low computation complexity that improves significantly the performance of conventional PLLs system. An analysis of the challenges of computation complexity in this algorithm is presented. The simulation results for DOA estimation using the proposed structure with low complexity are shown to verify the performance of the system.