Passive range estimation using subarray parallax

Abstract

Consider a large aperture linear array which is detecting coherent radiation from a source. Suppose that the array is processed as a string of subarrays consisting of adjacent sensors. Assume that the signal is a plane wave whose coherence distance is of the order of the subarray lengths. There is a systematic difference among the subarray bearing estimates due to parallax. A statistical method for using the parallax effect to estimate range is presented. Approximate expressions for the variance and bias of the estimator are derived under the assumption that the gain of each subarray is large. These theoretical results are compared with values obtained using artificial data for several parameter values.