Study On Collaborative Optimization Design Of Satellite Constellation

The growing demand of the global resource exploration, space-based early warning, navigation and wireless communications services promote the rapid development of the satellite constellation system design method. The design of satellite constellation system is a typical large-scale, highly constrained, multi-objective and multidisciplinary optimization design problems. Collaborative optimization method has succeeded to solve such design problems. The distributed analysis architecture of Collaborative optimization method can effectively improve the quality of the satellite constellation system design and reduce the total cost of the design and deployment of satellite constellation, which has the very important practical significance for the design of satellite constellation system that can be afforded. In order to improve the efficiency of satellite constellation design and reduce the computation complexity of collaborative optimization method for satellite constellation design, a satellite constellation design framework based on the improved collaborative optimization method is built after having investigated the satellite constellation design theory systematically.This improved design framework contains the following details:Firstly, the limitations of the traditional design method and the current optimization design method are pointed out. The strategy for original configuration selection of satellite constellation based on CART (Classification And Regression Tree) algorithm is put forward to overcome these limitations. With this strategy the selection space of original configuration selection is reduced the total space to a small space which contains less than eight stable constellation original configuration. Based on this strategy, the layer progressive design method is put forward after the strengths of three typical design methods of satellite constellation configuration are combined. With this method a configuration of regional navigation satellite constellation is designed. Compared with the existing configuration design methods of satellite constellation by Numerical simulation, the layer progressive design method has high computational efficiency and the long term stability constellation configuration can keep stable for a long time.Secondly, Non-dominated sorting algorithm of NSGA-II (Non-dominated Sorting in Genetic Algorithms II) is improved for the shortcomings of high computation complexity. The computation complexity of improved NSGA-II is O(MNlogN) which is far less than the original NSGA-II’s O(MN2), so the calculated quantity of NSGA-II is reduced. Improved NSGA-Ⅱ algorithm is used in the sub-discipline performance analysis of satellite constellation collaborative optimization design by Numerical simulation, and the calculation efficiency of satellite constellation collaborative optimization design is improved.Thirdly, Satellite constellation design involves many disciplines, and there are many times of system iterative computations during the period of satellite constellation collaborative optimization design. Furthermore, each iterative computation takes high computation overhead. For these reasons, an improved collaborative optimization method based on PID (Proportion Integration Differentiation) control is put forward. Compared with the original collaborative optimization method, the same design results are obtained by the improved collaborative optimization method, but the difference between the local value of discipline coupling variable and the target value of discipline coupling variable decreased more quickly so that with the improved collaborative optimization method the number of system-level iterations decreased by33.3percent. The calculated quantity is reduced significantly.The results showed that improvements in numerous aspects of the satellite constellation system design constitute a flexible and efficient collaborative optimization framework for satellite constellation design which promotes the modular design of satellite constellation system. Moreover, the total cost is the system-level Optimization Goal in the improved framework which lays a good foundation for the design of minimum cost satellite constellation system.