Preliminary Analysis of the Calibration Procedures for a Geodesic Antenna Array (GEODA)

Nowadays, earth stations for downloading data from LEO (Low Earth Orbit) satellites make use of large reflector antennas. These antennas pose a number of impairments regarding their mechanical complexity, lower flexibility, network efficiency and higher cost [1]. Furthermore, reflector antennas can track only one satellite at a time, so that the efficiency of the earth segment is reduced [2]. In order to improve the performance of traditional earth stations, the feasibility of other antenna technologies must be evaluated and one alternative are the conformal adaptive antennas based on multiple planar arrays as geodesic antenna array (GEODA) [3]. These antennas have several advantages over large dishes [4] and the efficiency to track several satellites simultaneously is a function of the number of antenna elements and the correct calibration of the antenna arrays. These antennas use adaptive beamforming algorithms with spatial reference to track the satellites, and the compute of a close approach of the spatial reference as well the direction of arrival depends on the calibration algorithm performance. In this paper an analysis of the calibration procedure for smart antennas to be implemented in the GEODA for satellites communications is presented