A Flexible Extension for Pico-Satellite Communication Based on Orbit Operation Results of UWE-1

Paper number

IAC-06-B5.2.05

Author

Mr. Florian Zeiger, Wuerzburg University, Germany

Coauthor

Mr. Marco Schmidt, Wuerzburg University, Germany

Coauthor

Prof. Dr. Klaus Schilling, Wuerzburg University, Germany

Year

2006

Abstract

The University of Wuerzburg’s Experimental Satellite 1 (UWE-1) is a pico-satellite, developed in the context of the international Cubesat program. UWE-1 has been launched on October 27th, 2005.
A central objective of UWE-1 is the integration of pico-satellite communication into IP based networks. To use IP for the communication between the ground station and LEO satellites, a certain level of reliability and performance of the lower protocol layers is required. A common solution, especially for pico-satellite communication, is the use of HDLC conform protocols like AX.25. The use of AX.25 causes problems due to the lack of a forward error correction (FEC). AX.25 only detects errors, but it is not possible to correct them. Furthermore, a suitable implementation of error detection and correction inside AX.25 is not intended to keep up the compatibility. Studies showed that a combination of HDLC with the appropriate forward error correction achieves also good results compared to specialized solutions like CCSDS. The implementation of a FEC inside the 6Pack protocol allows a further use of commercial-of-the-shelf (COTS) components and standard high level communication protocols.
This work gives an overview of the results we achieved from the in-orbit operation of UWE-1 and describes a tuning of protocols located at the MAC layer. This allows the use of AX.25 in environments with low bandwidth, high delays, and high packet loss. This flexible extension can be used optional to standard AX.25 communication which is common in the radio amateur community and is often used for the communication of LEO pico-satellites. UWE-1 performed in addition to the telecommunication tasks also technology demonstration tasks on miniaturization, highly efficient GaAs solar cells and uCLinux as on-board data processing system. It complies to the pico-satellite class with a size of 1 dm3 and a mass below 1 kg. The pico-satellite is a fully functional but highly integrated space vehicle.

Abstract document

IAC-06-B5.2.05.pdf

Manuscript document

IAC-06-B5.2.05.pdf (🔒 authorized access only).

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