Communications satellites

Onboard Processing for Communications Satellites

Future satellite networks may include satellites that provide multiple uplink and downlink coverage antenna beams together with signal processing subsystems. Where the number of earth terminals is large and the traffic is diffuse, efficient methods for routing signals need to be developed. This paper addresses the switching and routing processes for both long term connections (stream traffic) a...

Aititude Control of Flexible Communications Satellites

This paper investigates alternate control techniques for the attitude control of a three axis stabilized flexible communications satellite consisting of a large reflector and a solar array. The control configurations consisted of three classes: Class 1 sensors and actuators co-located on the central body, Class 2 actuator on the central body and sensors distributed, and Class 3 -actuators and s...

Downlink Communications from 50kg Class Small Satellites

Recently small satellites start playing important roles in earth observation missions. It, however, is true that small satellites have drawbacks of sensor resolutions and down link data rate. As a solution to the latter drawback, we have developed novel communications system for 320Mbps down link with 16QAM for small satellites with 50kg class. We developed a new GaN HEMT X-band amplifier with ...

Rain Fade Compensation for Ka-Band Communications Satellites

Communications by Means of Low Earth Orbiting Satellites

This tutorial paper describes the current development in the use of low earth orbiting satellites (LEOS) for global personal communications. The basic architectures and rationales for design choices are discussed. Representative TDMA and CDMA systems are outlined and a summary of the diierences between LEOS communications and terrestrial cellular is presented along with the prospects for CDMA b...