Old Communications Documentation

Welcome to the COMMUNICATIONS (COMS) Team Section

Coms last updated 19/06/2008

{By Shez W [SW149] & Tom D-M [TEJM1]}


INTRODUCTION TO COMS SUBSYSTEM

The primary goal of the communications subsystem is to provide a link to relay data to ground station and send commands to and from the CubeSat and as such will primarily consist of telemetry and command sequences that send and receive data respectively. Data is collected by the payload and sensors on the satellite in the form of analogue or digital data which must be sent to the ground station.

The communications subsystem (COMS) will perform two functions. It will provide the telemetry downlink and telecommand uplink functionality. It was hoped a linear transponder service (which can be used by amateur radio operators to communicate with each other) could be provided, however due to power constraints this will not be possible (sorry!). The satellite will uplink and downlink in the satellite segment of the UHF amateur radio frequency band of around 146 MHz (exact frequency to be decided). Telemetry downlink will be done using 9k6 Baud AFSK modulation, using the amateur standard AX.25 protocol. The system will be able to transmit 432kB in a 6 min overhead window (which is an underestimate of the time overhead).

The Cubesat kit accepts a range of off-the-shelf modems / transceivers. This comes with a USB-2.0-compliant USB port. This port can be used to communicate between the Cubesat kit and any PC or Mac running Windows, Mac OS X or Linux. CustomCubeSat Kit drivers for Windows and Mac OS X are provided.


Subsystem Contents

Please follow the links listed below to easily locate any communications information you require.
COMS Team Contacts
COMS Meeting Notes

COMS Concepts & Fundamentals
COMS Mission Requirements
COMS Work Package Breakdown (Includes rough Mass, Volume, Cost and Power budgets)
COMS System Definition
COMS Block Diagram
COMS Groundsegment Definition
Link Budget page
COMS Interface

Main Component Pages:

The Transceiver page
The TNC (Terminal Node Controller) page
The Antenna page


See Also:


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