THE TELESAT CANADA TRACKING, TELEMETRY AND COMMAND SYSTEM

Abstract

The Telesat Canada Tracking, Telemetry and Command (TT&C) System was developed to provide the Company with a system for geostationary orbit control and a dedicated capability for transfer orbit operations. For C-band (6/4 GHz), Telesat has evolved a costeffective mix of facilities based on a single tracking antenna and shared use of communications antennas, supplemented by low-cost fixed antenna systems. The satellite expansion program into Ku-band (14/12 GHz) required a parallel development of TT&C facilities. A unique feature of this development was the conversion of an existing 11-meter C-band antenna into a dual C- and Ku-band antenna, with a monopulse tracking system, employing an offset feed and tilting subreflector technique. Additional fixed Ku-band antenna systems were required to generate reliable beacons for RF sensor control of the communications antennas on the Anik C satellite, in the presence of deep fading conditions. This need, combined with a requirement for a long baseline for range measurement, resulted in the development of geographically widely separated, remotely operated T&C facilities. This paper is a description of the special features and performance of the Telesat TT&C System.