Design and Realization of Data Transmitter for Video Streaming of On-board Deployments in Geostationary Spacecrafts

Abstract

Recent geostationary spacecrafts are configured with video streaming feature during
deployment of critical onboard mechanisms such as Solar Array Drive Assembly and
Unfolding of Parabolic Antennae. To accomplish this, frames captured by the on board
camera are to be transmitted to ground station through a data transmitter. This data
transmitter has to share a narrow bandwidth of 20 MHz in C-Band with mission critical
telemetry transmitters of the host spacecraft and other co-located spacecrafts without
causing any interference. Since reliability and simplicity are the most important criteria in
the design of a mainframe system for a satellite, an architecture based on Binary Phase Shift
Keying (BPSK) modulation is chosen. RF carrier is generated through a compact X12
frequency multiplier that gets stable reference input signal from a Temperature Compensated
Crystal Oscillator (TCXO). The design also involves RF alignment and packaging strategies
to ensure the operation as per specifications through specified ranges of temperature and
vibration levels. The performance of the transmitter is found to meet all specifications post
launch.