A CAN based distributed telemetry and telecommand network for a nanosatellite
Date
2008-03
Authors
Journal Title
Journal ISSN
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Publisher
Stellenbosch : Stellenbosch University
Abstract
A communications protocol is designed for real time control and data handling for a
Nanosatellite application. The communication protocol is based on the Controller Area
Network (CAN) technology. The protocol handles different message types such as time
synchronization, telecommand messages, telemetry acquisition, unsolicited telemetry
messages, large file transfers and debug messages.
The design of the protocol entails finding a suitable target microcontroller in which the
protocol implementation is demonstrated. This requires consideration of a number of
development factors such as cost, complexity, availability, reliability and operational
environment (space). The AVR AT90CAN128 microcontroller was chosen as a target
microcontroller as it gave most of the required factors mentioned above.
The protocol implementation involves developing low level software drivers, the middleware
and the application programs to demonstrate handling of each supported message. In the
implementation the media access scheme and low layer communication is provided by the
CAN low level kernel (physical and data link layers).
The protocol performance was evaluated by measuring the software response latencies, the
bus throughputs and the software efficiencies. Power consumption due to CAN
communication was also measured.
System reliability was tested by loading the CAN bus with extreme communication traffic
and letting the system run for a long time. The observation was that messages were handled
consistently.
Description
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2008.
Keywords
CAN, Telelmetry, Telecommand, Network, Theses -- Electrical and electronic engineering, Dissertations -- Electrical and electronic engineering