US Patent 6920323 Satellite communications system and user terminal providing path diversity

In a satellite communications system, where a user terminal 10, on the surface of the earth 12, can be in diversity communication to an earth station 18 via two orbiting satellites 14, 16 at once, and there is a need, at some time, when one of the two satellites 14, 16 orbits our of range, to engage another satellite 22 in its place, the user terminal 10 is operative to suppress TDMA timeslots in its communications with the two satellites 14, 16 to listen and report on broadcast messages from another satellite 22, the suppressed timeslots being based on an assessment of which of the two satellites has the largest path attenuation.