Performance evaluation of correlative interferometry for angle of arrival estimation

Abstract

Radio direction finders are used to determine the direction of emitters and they are used by regulatory bodies, law enforcement, public safety and the Military. Bearings from multiple direction finders can be used by the process of triangulation to determine the position of emitters. There are several methods for radio direction finding; Watson Watt/Adcock method, Differential Doppler, Directional Antenna and Correlative Interferometry. The project proposes the implementation of Correlative Interferometry for angle of arrival (AOA) estimation. The Correlative Interferometry processing involves the comparison of the measured phase differences between the antenna elements of the direction finder (DF) antenna system with those obtained for the same antenna system at all possible directions of incidence. The comparison is made by calculating the correlation of the two data sets (or the scalar product of two vectors obtained by multiplying the coordinates element by element and summing the result). Using different comparison data sets for different wave directions, the bearing is estimated from the data set for which the correlation is at a maximum. Various configuration of the algorithm is investigated so that that the amount of processing and memory was optimized with accuracy in the measurement of the direction. From the optimum structure, Monte Carlo simulation is carried out to evaluate the mean and variance of multiple AOA estimates for various signal-tonoise ratios (SNR).