Doppler method for angle of arrival estimation

Abstract

Radio direction finder, which utilizes angle-of-arrival (AOA) estimation, is a function in a radio monitoring system to estimate the direction of the signal. A radio monitoring system can be used to estimate the parameters of a received signal and determines its direction. The system is used in a large area of application and the major users of radio monitoring systems are regulatory bodies, law enforcement, public safety and the military. There are two types of DF techniques, multi-channel direction finding and single channel DF techniques. In this work, the single channel technique is implemented. The single channel DF systems offer several advantages over multiple channel systems, such as lower power consumption, portability and lower cost compared to the other DF technique. Basically, all DF systems are set to derive emitter location and the AOA. There are several methods of single channel DF, such as Watson Watt/Adcock method, pseudo-Doppler and correlative interferometry. In this project, the pseudo-Doppler DF techniques for angle of arrival estimation is implemented. The radio direction finder, which implement the Doppler method, consists of a circular antenna array that rotates at a constant speed. Signals received are spatially located and the rotation of the antenna introduces Doppler shift in the received signals. The Doppler method utilizes the Doppler shift and the spatial location of the receiving antenna to estimate the AOA for the received signals. The performance of the system was verified by Monte Carlo simulation to determine the effect of variance in the AOA estimation and location at various signal-to-noise ratios (SNR).