Battery-Aware Scheduling in Low Orbit: The GomX–3 Case
When working with space systems the keyword is resources. For a satellite in orbit all resources are sparse and the most critical resource of all is power. It is therefore crucial to have detailed knowledge on how much power is available for an energy harvesting satellite in orbit at every time – especially when in eclipse, where it draws its power from onboard batteries. This paper addresses this problem by a two-step procedure to perform task scheduling for low-earth-orbit (LEO) satellites exploiting formal methods. It combines cost-optimal reachability analyses of priced timed automata networks with a realistic kinetic battery model capable of capturing capacity limits as well as stochastic fluctuations. The procedure is in use for the automatic and resource-optimal day-ahead scheduling of GomX–3, a power-hungry nanosatellite currently orbiting the earth. We explain how this approach has overcome existing problems, has led to improved designs, and has provided new insights.
- 1.Uppaal Cora (2005). http://people.cs.aau.dk/~adavid/cora/introduction.html
- 3.Behrmann, G., Fehnker, A., Hune, T., Larsen, K., Pettersson, P., Romijn, J., Vaandrager, F.: Minimum-cost reachability for priced time automata. In: Benedetto, M.D., Sangiovanni-Vincentelli, A. (eds.) HSCC 2001. LNCS, vol. 2034, pp. 147–161. Springer, Heidelberg (2001). doi:10.1007/3-540-45351-2_15 CrossRefGoogle Scholar
- 6.Jongerden, M.R., Haverkort, B.R.: Which battery model to use? IET Softw. 3(6), 445–457 (2009). http://dx.doi.org/10.1049/iet-sen.2009.0001
- 7.Jongerden, M.R.: Model-based energy analysis of battery powered systems. Ph.D. thesis, Enschede. http://doc.utwente.nl/75079/
- 8.Larsen, K., Behrmann, G., Brinksma, E., Fehnker, A., Hune, T., Pettersson, P., Romijn, J.: As cheap as possible: effcient cost-optimal reachability for priced timed automata. In: Berry, G., Comon, H., Finkel, A. (eds.) CAV 2001. LNCS, vol. 2102, pp. 493–505. Springer, Heidelberg (2001). doi:10.1007/3-540-44585-4_47 CrossRefGoogle Scholar