Study on ISL network structure in LEO satellite communication systems
- Paper number
IAC-05-B3.6.03
- Author
Dr. Ryutaro Suzuki, National Institute of Information and Communications Technology, Japan
- Coauthor
Prof. Yasuhiko Yasuda, Waseda Universiy, Japan
- Year
2005
- Abstract
In designing a LEO satellite constellation, many parameters have to be taken into account including transmission delay, service coverage, minimum elevation angle, and the effect of space radiation. A satellite constellation with ISL connection was discussed for the NeLS project. To maintain continuous ISL connection, we selected the 2π constellation, which is expressed by using a Walker notation of 120/10/1 with 55 degrees of inclination. To enable satellite diversity, orbit parameters were examined under the condition that at least two satellites are always visible from the user terminal. The optimum inclination angle for 2π constellation was derived directly from the spherical triangle formed by adjacent three satellites. In evaluating of the NeLS’s ISL performance, the ISL connection structure was simplified by using constellation parameters of 121/11/0 instead of 120/10/1. With these parameters, the ISL network had a bi-directional MSN structure. The inter-orbital ISL, especially, by using n to n-1, achieved a figure-of-eight shaped ring network. The figure-of-eight ring network may offer advantages with short connection delays in the north-south direction, and can be applied to regional connections under hierarchical control of the ISL network. Moreover, the optimum inclination was applied to Globalstar system, and the minimum elevation angle in low latitude area was improved. The bi-directional MSN topology of ISL connection was also discussed. In n to n-1 connection of inter-orbital ISLs, a combination of constellation parameters P, S, and F were found to have simple relations. Finally optimum parameters for the NeLS constellation were discussed, and a candidate parameter (T/P/F = 132/11/-1, h = 1100 km and I = 57.92 degrees) was shown.
- Abstract document
- Manuscript document
IAC-05-B3.6.03.pdf (🔒 authorized access only).
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