Viasat, Inc.

Scientific-atlanta, Inc.

Rodney A Morris

Mark Vanderaar

John R Zlogar

David E Sinyard

Patrick E Tynan

A method performed by a ground station antenna system for tracking a non-Geo satellite. A signal is received from the satellite and a signal quality metric associated with the signal is estimated. A first tracking mode is selected and implemented when the estimated signal quality metric is below a threshold, in which the signal is demodulated to obtain demodulated signal quality metric (DSQM) estimates, and then a first tracking operation is performed to point an antenna beam at the satellite based on the DSQM estimates. A second tracking mode is selected and implemented when the estimated signal quality metric is above the threshold, in which signal strength estimates of the signal are obtained and then a second tracking operation is performed to point the antenna beam at the satellite based at least in part on the signal strength estimates.

Antenna systems and methods for tracking non-geosynchronous satellites

A satellite communications system adjusts a modulation and coding format for a downlink based on the slant range distance from the satellite to the receiving ground terminal. Modulation and coding formats are each associated with different sets of slant range distances. An estimated slant range from a satellite to a receiving ground terminal for a time period is determined, and the modulation and coding format associated with that slant range distance is identified. Data may then be transmitted by the satellite to the receiving ground terminal using the identified modulation and coding format for the time period. Additional factors may be considered in identifying the applicable modulation and coding format to be used.

Modulation and coding adjustment based on slant range characteristics for satellite downlinks

An automatic gain control circuit for use in a multichannel RF system using fiber optic links. The circuit samples the power levels from a number of attenuated RF signals simultaneously and adjusts the gain in all of the channels by the amount required to keep the highest power channel below a predetermined power level determined by the power capacity of the fiber optic link while maintaining the signal strength relationship between the attenuated signals as was existing between the RF input signals.

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Lawrenceville, GA, United States of America

Rodney A Morris