Performance evaluation of passive direction finding systems in a multi-path environment

The performance of amplitude- and phase-based passive direction finding (DF) systems is evaluated in a multi-path environment. For performance analysis and fair comparison, a parametric circular DF array is modelled and analyzed in a two-wave (direct and reflected) environment. The parameterized model varies the aperture size and number of antenna elements of DF array, frequency, strength and angle-of-incidence of direct and reflected waves. The root-mean-square (RMS) bearing error is estimated for all the possible combinations of the said parameters. The MATLAB simulation results based on the analytical model show the better reflection immunity of the phase-based direction finding system in a multi-path environment, subject to the selection of appropriate antenna-pattern and field-of-view.