Direction finding using two differential sensors of possibly unequal orders, with perpendicular orientation and possible displacement

Abstract

A differential sensor has a directional response which approximates a measurement of the kth-order spatial derivative of the pressure field. A sensor array composed of a pair perpendicularly-oriented higher-order (possibly unequal orders) differential sensors can be used to find the direction of acoustic signal sources. The objective of my research is to devise a signal-processing algorithm to estimate the direction-of-arrival (DOA) of a signal incident upon this type of sensor array. A viable approach is herein proposed. The new direction finding method relies on well-known eigen-based DOA estimation algorithms as a preceding stage. The closed-form formulas can be then directly applied when certain prior knowledge is available. This dissertation presents the derivation of closed-form formulas for elevation and azimuth angle estimation with nine possible configurations. Necessary assumptions and prior information needed for the algorithm are also discussed. Monte Carlo simulations result shows that the proposed algorithm can successfully estimate the elevation and azimuth angle of incident signal. The corresponding Cram´er-Rao Bounds (CRB) are derived so as to evaluate the performance of proposed algorithm.