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 adata 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.