APPA: A Phased Array System Designed for Space Application

Artificial pilot phased array (APPA) is a system designed for application as a multiple narrow-beam communication satellite. The design uses an adaptive array principle in a multiple-beam configuration. Two ground pilot signals are used to make beam steering independent of array attitude. Beam steering is accomplished without the requirement of user pilots by deriving array phase shifter settings from user locations. The system´s principle of operation is persented along with a description of a laboratory model and a design application to a data relay satellite.