Ground Station Networks for Efficient Operation of Distributed Small Satellite Systems [Elektronische Ressource] / Marco Schmidt. Betreuer: Klaus Schilling

Schmidt Francis

Sujets

• Informatik

Informations

• Publié par: julius-maximilians-universitat_wurzburg
• Publié le: 01 janvier 2011
• Nombre de lectures: 40
• Langue: Deutsch
• Poids de l'ouvrage: 7 Mo

Extrait

Institut für Informatik
Lehrstuhl für Robotik und Telematik
Prof. Dr. K. Schilling
Würzburger Forschungsberichte
in Robotik und Telematik
Uni Wuerzburg Research Notes
in Robotics and Telematics
Marco Schmidt
Ground Station Networks
for Efficient Operation of
Distributed Small
Satellite Systems
Band 6Die Schriftenreihe
wird vom Lehrstuhl für Informatik VII: Robotik und Telematik der Universität
Würzburg herausgegeben und präsentiert innovative Forschung aus den
Bereichen der Robotik und der Telematik.
Die Kombination fortgeschrittener Informationsverarbeitungsmethoden mit
Verfahren der Regelungstechnik eröffnet hier interessante Forschungs- und
Anwendungsperspektiven. Es werden dabei folgende interdisziplinäre Aufgaben-
schwerpunkte bearbeitet:
Robotik und Mechatronik: Kombination von Informatik, Elektronik, Mechanik, Ÿ
Sensorik, Regelungs- und Steuerungstechnik, um Roboter adaptiv und flexibel
ihrer Arbeitsumgebung anzupassen.
Telematik: Integration von Telekommunikation, Infor-matik und Steuerungs-Ÿ
technik, um Dienstleistungen an entfernten Standorten zu erbringen.
Anwendungsschwerpunkte sind u.a. mobile Roboter, Tele-Robotik, Raumfahrts-
ysteme und Medizin-Robotik.
Lehrstuhl Informatik VII
Robotik und Telematik
Am Hubland
D-97074 Wuerzburg
Tel.: +49 (0) 931 - 31 - 86678
Fax: +49 (0) 931 - 31 - 86679
[e-mail]
http://www7.informatik.uni-wuerzburg.de
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ISSN (Internet): 1868-7474
ISSN (Print): 1868-7466
eISBN: 978-3-923959-77-8
Zitation dieser Publikation
SCHMIDT, M. (2011). Ground station networks for efficient operation of
distributed small satellite systems. Schriftenreihe Würzburger
Forschungsberichte in Robotik und Telematik, Band 6. Würzburg: Universität
Würzburg.Ground Station Networks for
Efficient Operation of
Distributed Small Satellite Systems
Dissertation zur Erlangung des
naturwissenschaftlichen Doktorgrades
der Julius-Maximilians-Universität Würzburg
vorgelegt von
Marco Schmidt
aus
Würzburg
Würzburg 2011Eingereicht am: 13.5.2011
bei der Fakultät für Mathematik und Informatik
1. Gutachter: Prof. Dr. Klaus Schilling
2. Gutachter: Prof. Dr. Shinichi Nakasuka
3. Gutachter: Prof. Dr. Hakan Kayal
Tag der mündlichen Prüfung: 29.7.2011Contents
1 Introduction 1
1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Background 7
2.1 Small satellites in education and research . . . . . . . . . . . . . . . . 7
2.1.1 The small satellite concept . . . . . . . . . . . . . . . . . . . . 7
2.1.2 Evolution of the pico and nano-satellite approach . . . . . . . 10
2.1.3 The UWE satellite series . . . . . . . . . . . . . . . . . . . . . 12
2.2 A new concept of ground station networks . . . . . . . . . . . . . . . 17
2.2.1 Classic and academic ground station networks . . . . . . . . . 18
2.2.2 Projects establishing academic ground station networks . . . . 23
2.3 Distributed / multi satellite systems . . . . . . . . . . . . . . . . . . . 26
2.3.1 Distributed as a new paradigm for satellite
missions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.3.2 Application scenarios for distributed satellite systems . . . . . 30
2.3.3 Example mission . . . . . . . . . . . . . . . . . . . . . . . . . 32
2.4 Challenges and technologies for distributed space missions . . . . . . 32
2.4.1 Challenges for highly satellite . . . . . . . 33
2.4.2 Technologies for distributed space missions . . . . . . . . . . . 35
3 Redundant scheduling for ground station networks 39
3.1 State of the art . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.1.1 Satellite Range Scheduling . . . . . . . . . . . . . . . . . . . . 41
3.1.2 Earth Observation Scheduling (EOS) . . . . . . . . . . . . . . 45
iii3.1.3 ESA tracking stations - ESTRACK . . . . . . . . . . . . . . . 47
3.1.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
3.2 Scheduling for low cost ground station networks . . . . . . . . . . . . 48
3.2.1 Scheduling requirements of academic ground station networks 51
3.2.2 Problem description . . . . . . . . . . . . . . . . . . . . . . . 52
3.2.3 Scheduling objective . . . . . . . . . . . . . . . . . . . . . . . 55
3.2.4 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.3 Scheduling approach . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.3.1 System overview . . . . . . . . . . . . . . . . . . . . . . . . . 58
3.3.2 Scheduling objective function . . . . . . . . . . . . . . . . . . 59
3.3.3 Behavior of the penalty function for two arbitrary requests . . 62
3.3.4 Redundancy distribution for more than two arbitrary requests 64
3.3.5 Search algorithms . . . . . . . . . . . . . . . . . . . . . . . . . 69
3.3.6 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.4 Performance evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . 74
3.4.1 Evaluation criteria . . . . . . . . . . . . . . . . . . . . . . . . 75
3.4.2 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
3.4.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
3.5 Conclusion and discussion . . . . . . . . . . . . . . . . . . . . . . . . 87
4 Data management for information recovery in ground networks 91
4.1 Problem definition and state of the art . . . . . . . . . . . . . . . . . 93
4.1.1 Problem description . . . . . . . . . . . . . . . . . . . . . . . 94
4.1.2 Data and network management in computer networks . . . . . 98
4.1.3 Data management for information recovery . . . . . . . . . . . 99
4.1.4 Time synchronization . . . . . . . . . . . . . . . . . . . . . . . 102
4.2 Synchronization in academic ground station networks . . . . . . . . . 103
4.2.1 Time synchronization between ground stations . . . . . . . . . 106
4.2.2 Data sync on frame level . . . . . . . . . . . . . . . 114
4.3 Data combination in academic ground station networks . . . . . . . . 118
4.3.1 Ground station majority voting approach . . . . . . . . . . . . 118
4.3.2 Brute force method for data recovery . . . . . . . . . . . . . . 122
4.3.3 Single bit error correction in AX.25 . . . . . . . . . . . . . . . 123
4.4 Performance analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
4.4.1 Performance of the data combination algorithm . . . . . . . . 127
iv4.5 Hardware tests and results . . . . . . . . . . . . . . . . . . . . . . . . 133
4.5.1 Ground station network simulation . . . . . . . . . . . . . . . 133
4.5.2 Local ground station network with radio link . . . . . . . . . . 142
4.6 Conclusion and future work . . . . . . . . . . . . . . . . . . . . . . . 149
5 Conclusion 151
A Propagation delay in Low Earth Orbits (LEO) 155
B OSI layer model for satellite communication 159
C Satellite orbit data for evaluation of CUSS 163
vChapter 1
Introduction
1.1 Motivation
In the last 10 years emerged a new approach in the field of satellite engineering.
The idea of sending extremely small satellites into space originated from educa-
tional institutions and then adopted in diverse application fields. This paradigm
shift involved building satellites from commercial of-the-shelf components, designed
forrestrictedlifetime,butataffordableprices. Manyofthesepicoandnano-satellites
were already brought into orbit. The University of Würzburg contributed in that
scope with the University of Wuerzburg Experimental satellites (UWE) and demon-
strated successfully how extremely small satellites can be used to perform innovative
space research.
A benefit of designing lightweight satellites is, that they can be launched ’piggyback’
as secondary payloads, and hence at moderate costs. This makes it possible to in-
stall networks of satellites, carried from a single launch vehicle into space. Many
researchers look at satellite networks (especially formations) as the next necessary
step to transfer successful terrestrial distributed system technology to the context
of space exploration, for example at utilizing virtual instruments or very long base-
line interferometry. The concept of networked satellites promises progress in diverse
application fields. Specifically from a computer scientists point of view, the network
aspect is very interesting, although it is known that handling and controlling dis-
tributed systems is very challenging.
To better illustrate such issues, let us assume a satellite cluster of 10 small satellites
is placed in similar low Earth orbits, acting together to achieve a common mission
12
goal. On the receiving side, 30 ground stations are available, geographically dis-
tributed over Europe. The starting point for this work was a simple question: How