Direction Finding
Randy L. Haupt · 2020
Direction finding (DF), also known as angle of arrival (AOA) or direction of arrival estimation, locates radio frequency signals in the environment. This chapter begins by presenting some relatively simple approaches to DF that uses the main beam or one null. Many DF algorithms need to know the number of signals incident on the array. The elevation and azimuth of the antenna pointing direction determines the angular location of the signal. The chapter explains how to exploit the covariance matrix to find the location of signals. Strong signals entering the sidelobes overwhelm a weaker signal received by the main beam, leading to poor AOA estimates. The Multiple Signal Classification algorithm accurately estimates the number and strengths of signals as well as their AOA for a calibrated array and uncorrelated signals. Estimation of Signal Parameters via Rotational Znvariance Techniques applies stereoscopy to AOA estimation.