Signal Acquisition Techniques for Receiving Arrays of Large-Aperture Antennas

This paper considers the signal phase acquisition problem for arrays of large-aperture steerable antennas. In particular, long-range signal acquisition is considered for those cases in which the signal-to-noise ratio in each antenna-receiver channel is too low to permit signal phase-lock in each individual receiver. Techniques are discussed which promise to extend the array acquisition sensitivity toward that of an equivalent-area single-aperture antenna. Several acquisition methods are analyzed mathematically and an approximate minimum power threshold estimated for each technique. A numerical comparison between the acquisition techniques for various assumed atmospheric conditions is presented which indicates the limitations on array sensitivity imposed by both the transmission medium and the acquisition technique.