A system and method for managing access to a satellite-based transponder
by a plurality of aircraft each having a mobile radio frequency (RF)
system. The system employs a ground-based, central control system for
managing access to the satellite-based transponder so that the aggregate
power spectral density (PSD) of the RF signals of all the mobile systems
does not exceed, at any time, limits established by regulatory agencies
to prevent interference between satellite systems. This is accomplished
by a dual control loop arrangement for monitoring the signal-to-noise
ratio (Eb/No) of the RF signal transmitted by the satellite-based
transponder. A ground-based control loop is used whereby a ground-based
central controller monitors the Eb/No and transmits commands to the
aircraft (via the satellite transponder) to maintain the Eb/No of the
transmitted signal within a predetermined range. A fast scan angle
compensation is used by the mobile system of the aircraft to implement
another control loop to further adjust the transmit power. This control
loop maintains the Eb/No of the signal transmitted to the satellite-based
transponder at the commanded level inbetween updates from the
ground-based central controller.