The LES-8/9 Telemetry System: Pt II, Ground Terminal Design and Performance

Abstract

The LES-8/9 telemetry ground terminal is a distributed system providing simultaneous reception of digitally encoded telemetry from both LES-8 and LES-9 satellites via S-band, K-band, and UHF downlinks at ground commendable rates of 100-bps and 10-Kbps. Antenna control and demodulation as well as frame synchronization and error detection are provided at a centralized facility, and resultant baseband telemetry is distributed in processed digital format over serial-data lines through a coaxial-cable distribution network. Comprehensive, realtime telemetry processing is provided by separately located minicomputers which provide alphanumeric data displays to a distributed network of standard TV-type video monitors. Telemetry is recorded directly in IBM compatible form under minicomputer control and selection, with post-processing performed at the IBM-370 Lincoln Computation Center. Additional real-time processing is also provided by dedicated panels portraying subsystem operations. Extensive operational software has been developed for evolving needs from initial satellite integration and test through post-launch operation and monitoring. These programs as well as the related hardware equipment and organization are described and traced through the course of the LES-8/9 project.