Patent ID: 6263188
Filing Date: 2001-07-17
Classification: B64G,H04B

Abstract:
A satellite communication system, comprising:a ground station, including a communication system with communications equipment therein, and a steerable antenna which includes steering elements which are steered to aim at different selectable locations;a plurality of satellites in orbit, each said satellite having communication equipment thereon which operates only a part of a total time, said satellites communicating with said ground station equipment via said antenna, said satellites orbiting in elliptical orbits at altitudes lower than those necessary for geosynchronous orbit by at least 25%, having apogees and perigees, and said satellites having ground tracks which cover the ground and which repeat over time, said ground tracks having a path, and said satellites spaced in said path, such that said ground communication system is always within a footprint centered around the ground track of a satellite which is near an apogee portion of its orbit;an antenna steering element, steering said antenna to follow a pattern which repeats over an integral number of times each day, to follow said satellites in orbit; andan antenna control system operating to steer a position of an antenna which communicates between said ground station and said satellite, said antenna control system including means for determining an angle of that antenna relative to said ground, and means for determining if said angle points toward a geosynchronous satellite orbital band, and means for stopping said communication when said angle points toward said geosynchronous satellite orbital band.