A signal detectability approach to optimization of the geometry of distributed aperture (array) receivers

A technique which allows the analytical specification of optimal array geometry that enhances array reception is developed. The technique is illustrated for small antenna arrays of up to four elements in two classes of interference fields, with and without spatial constraints. The analytical treatment is predicated upon signal detectability and employs error-free arrays of noninteracting nondirectional elements. The interference fields considered are those due to isotropic sources (case I) and sources uniformly distributed on an unbounded plane (case II). The optimality criterion is minimization of the signal detection error probability. For a phased receiving array, this is equivalent to maximizing the array detectability gain function, which has the effect of maximizing the predetection signal-to-noise ratio (SNR). The optimal array configuration is found to be two-dimensional in both cases (circular configuration in case I and elliptical configuration in case II, with the antennas equally spaced in angle along the periphery of the configuration). Numerical results are given which indicate that practical increases in predetection SNR of as much as 10 to 15 dB can be achieved by employing the array configuration most appropriate for the space-time correlation structure of the interference fields.