Research On Mission Planning And Control Problem For Distributed Imaging Satellite System Based On MAS

Distributed imaging satellite system composed of modern intelligent small imaging satellites is the main earth observing satellite application system in the future. Distributed imaging satellite system is a kind of agile satellite system that is intelligent and distributed. The problem of mission planning and control for the distributed imaging satellite system is defined as: considering the characteristics of the distributed imaging satellite system and the requirement of dynamic observing environment sufficiently, assign various observing missions to the satellites among distributed imaging satellite system optimally. Then generate the detail action plan of every satellite through automatically reasoning, so as to control the satellite autonomously to complete the observing missions. The mission planning and control problem for distributed imaging satellite system is still a brand new problem for researchers either inside or outside the country at present. As the development of modern small satellite and distributed satellite system rapidly, and the research of mission planning technology for multi-satellites and autonomous satellite technology growing on, the investigation on such problems is of great significance both from the theory or application viewpoints. Based on the understanding of components and operation of distributed imaging satellite system, this thesis provides a framework for mission planning and control of distributed imaging satellite system, investigates mission planning technology for satellite cluster, autonomous control model and algorithm for satellite. At last, a prototype of mission planning and control system for distributed satellite system is developed. The main contents and fruits of this paper are outlined as follows:Firstly, this thesis divides the whole problem into two sub decision problems based on analyzing the imaging principle of satellite and the operating process of satellite system. The method based on agent and multi-agent system (MAS) is used to research distributed imaging satellite system according to the distributed and intelligent attributes of distributed imaging satellite system, so as to a kind of MAS structure with high reliability for distributed imaging satellite system and a hierarchical mixed agent structure for single satellite are designed separately. Based on these structures, this thesis analyzes the mechanism of mission planning and control based on MAS, and proposes the mission planning and control framework based on MAS for distributed imaging satellite system.Secondly, this thesis proposes a distributed dynamic mission planning approach based on multi-agent negotiation. This approach improves on the traditional contract-net protocol and a constraints-based honest contract-net protocol is designed eventually, which schedules the observing missions of satellite cluster by means of bidding. The means of feasibility test for mission insertion is presented and the algorithms for verifying the satisfiability of corresponding time window constraint and power constraint are given in detail. According to the operation character of distributed satellite system, the rules of optimizing the fuel consumption and the index of mission trade-off are proposed. This thesis also compares the performance of these rules, and suggests the strategy of utilizing rules.Thirdly, this thesis analyzes the applicability of HTN-based planning approach for autonomous control problem of satellite. The domain model of intelligent satellite is constructed using planning domain definition language, and then the autonomous control problem of satellite is solved by the HTN-based planning approach. This thesis provides two guided state space search algorithms based on task network. At last, an example is given to demonstrate that the HTN-based planning approach can solve the autonomous control problem of satellite effectively.Lastly, this thesis devises and realizes the prototype of mission planning and control system for constellation. In addition, this thesis gives an example and solves it by the prototype system. The results verify the validity of the proposed distributed dynamic mission planning approach for distributed imaging satellite system, HTN-based autonomous control approach for single satellite, corresponding algorithms, and prototype system.