Design and Implementation of In Orbit Experiments for the Pico Satellite UWE-1

Paper number

IAC-06-E2.1.07

Author

Mr. Marco Schmidt, Wuerzburg University, Germany

Coauthor

Mr. Florian Zeiger, Wuerzburg University, Germany

Year

2006

Abstract

UWE-1, a research-satellite of the pico-satellite class, was successfully brought to its orbit on the 27th of October 2005. UWE-1 is a fully functional pico-satellite, designed as a low-cost orbital test platform. The topology is based on commercial-of-the-shelf (COTS) components and a complete Linux Operating System (uClinux) enables a flexible usage of the satellite for a broad spectrum of test-scenarios.
Pico-satellites must comply with many restrictions because of its structural design patterns regarding capacity, weight, and power consumption, which affect the usage and operation of UWE-1 as an experimental platform. One of the UWE-1 mission objectives is the execution of communication experiments to characterize the radio-link between satellite and ground station. The analysis of the communication link is a necessary step for integrating pico-satellites in a worldwide IP-based communication network with several ground stations.
This work describes the design and implementation of different experiments, used to characterize the communication-link under the consideration of the requirements for pico-satellites. The design of the experiments had to be adapted to the restrictions of low bandwidth and resources. Therefore a special solution was developed for measuring the Bit Error Ratio (BER). Furthermore the communication was optimized for all the experiments by detailed investigation of the AX.25 protocol in combination with higher protocol layers. The experimental phase begun with determining the BER and its correlation to different disturbances. In a later phase, UWE-1 was running a webserver using TCP Westwood.
The results from this work can be used to get an optimal throughput of the AX.25 connection. This can also be applied in a radio link communication to reduce the probability of packet collisions. Furthermore the results will be used for further investigation of performance-optimizations, for example an additional forward error correction in combination with AX.25. 

Abstract document

IAC-06-E2.1.07.pdf

Manuscript document

IAC-06-E2.1.07.pdf (🔒 authorized access only).

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