Scan Loss Pattern Synthesis for Adaptive Array Ground Stations

Abstract

We present several techniques for maximizing the contact time between low Earth orbiting satellites (LEOs) and a ground station (GS). The GS comprises an adaptive array of electronically steered space-fed lenses (SFLs). Each SFL is manufactured as a low-cost printed circuit with the result that it exhibits scanning loss. By differently orienting the boresights of the SFLs in the adaptive array, the SFL's scanning losses can be made to optimally complement the path loss of the LEO, thereby reducing the cost of the GS while maximizing the download capacity of the satellite link. The optimization, implemented with a genetic algorithm (GA), can be viewed as a kind of pattern synthesis. Such arrays will benefit Earth exploration satellite service (EESS) and telemetry applications, promising a decreased cost and increased reliability as compared with GSs consisting of a large dish antenna. We show that a network of these GSs comprising a total of fourteen small antennas can achieve an average daily data rate that is comparable with that of a single large dish antenna for the Earth Observing One (EO-1) satellite, without increasing the output power of the satellite. We also analyze the case in which the satellite transmits with a variable bit rate (VBR). Furthermore, we show that by selectively populating the focal surface of the SFL with feeds, simultaneous communications with multiple satellites can be achieved with a single GS.