Queueing theory application in imaging service analysis for small Earth observation satellites
- Paper number
IAC-06-B5.3.05
- Author
Ms. Wen Chen, Surrey Space Centre, University of Surrey, United Kingdom
- Coauthor
Dr. Stephen Mackin, Surrey Satellite Technology Ltd., United Kingdom
- Coauthor
Dr. Philip L. Palmer, Surrey Space Centre, University of Surrey, United Kingdom
- Coauthor
Mr. Gary Crowley, United Kingdom
- Year
2006
- Abstract
Traditionally the performance of earth observation satellites is analysed based on system simulation results or real ground station data, which is usually accurate but not systematic. Modelling the satellite service system and analyzing the performance statistics systematically is needed for system optimization in design stage, and also will provide a useful guide in designing novel satellite mission planning and scheduling schemes. Queuing theory, as a systematic methodology for performance analysis of service systems, has been applied intensively in telecommunication and networking area with great success, providing useful service performance evaluation for system design and optimization. In this paper, queuing theory will be introduced to model the behaviour of the commercial LEO satellites and analyse the imaging service performance. A Satellite observation service consists of two stages: imaging and downloading. The requests completing the imaging service in the first stage enter the second image downloading stage. That is two queues in tandem. These two queues have been analysed individually in previous studies, assuming no memory constraint onboard the satellite. In the real system, however, memory capacity is one of the most important system parameters and has a large effect on the system performance, even causing a performance bottleneck for some small satellites. In this paper, a two-dimensional Markov chain model is proposed for modelling the small LEO imaging satellite, where memory constraints are considered. Some basic service performance parameters, such as queue length distribution and mean service rate for both two queues, are calculated, and then more useful measurements like request waiting time could be derived. The effects of system parameters such as memory capacity and download rate are investigated accordingly. All analytical results presented are compared with results from simulation. The limitation of this model is also discussed and future model revision is outlined. From this work we can see the queuing model can reflect the general service performance and system parameters’ effects of earth observation satellites, which is critical for system design and optimization.
- Abstract document
- Manuscript document
IAC-06-B5.3.05.pdf (🔒 authorized access only).
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