Adaptive cross-sensor beam forming with planar arrays

Abstract

In cross-sensor beamforming the narrow-band quadrature signal at one sensor is multiplied by the complex conjugate of the narrow-band quadrature signal at a second sensor to form a stable element of the cross-sensor field. After suitable time averaging, the beam response can be calculated as the weighted correlation between the cross-sensor field that is measured and the field that is expected. If N sensors form a sparse line array, then N lines form a sparse square array. Examples are given showing the performance of a sparse square array and a random planar array in resolving a realistic multiwave signal plus noise field. A simple adaptive algorithm is used to resolve weak signals close to strong signals and to reduce sidelobe problems associated with a random array.