Chinese Journal of Computers   Full Text
Title	Clonal Selection Land-Based Satellite Tracking Telemetry and Command(TT&C) Resources Scheduling Based on the Mission Oriented Model
Authors	HOU Cui-Qin JIAO Li-Cheng
Address	(Key Laboratory of Intelligent Perception and Image Understanding of Ministry of Education of China, Institute of Intelligent Information Processing, Xidian University, Xi′an 710071)
Year	2009
Issue	No.8(1525—1535)
Abstract &   Background	Abstract This paper proposes a novel model, the mission oriented model, for the problem of land-based satellite tracking telemetry and command (TT&C) resources scheduling. Compared to other models, the mission oriented model constrains a satellite to be tracked and commanded by only a ground station which can observe the satellite. Therefore, the proposed model makes it possible that scheduling algorithms schedule TT&C resources to complete more missions. Then it proposes the clonal selection land-based satellite TT&C resources scheduling algorithm (CS_STT&CRSA) based on the mission oriented model and proves its global convergence in theory. The algorithm adopts a matrix coding scheme, which depends on the start times of tracked and commanded orbits and the relationships between satellites and ground stations. The severe-constraint satisfaction operator which guarantees the individual satisfies severe constraints is proposed. When there are 5 geostationary satellites and 30, 40 or 50 low earth orbit and medium earth orbit (LEO&MEO) satellites, 10 different groups of tasks are generated respectively. Experimental results illustrate that the mission oriented model enables scheduling algorithms to make better use of TT&C resources and complete more missions and CS_TT&CRSA has more powerful ability of searching and solving constraints and is more stable. Keywords matrix coding scheme; satellite tracking telemetry and command (TT&C) resources; mission oriented model; clonal selection; scheduling algorithm Background This work is supported by the National Natural Science Foundation of China with the title “Kinetic Models of Artificial Immune Systems and Their Applications in Intrusion Detection”, the National High Technology Research and Development Program (863 Program) of China with the title “High-Performance Optimal Computation Models Based on Organizational Evolution and Immune Kinetics and Their Key Techniques” and the Program for Cheung Kong Scholars and Innovative Research Team in University with the title “Intelligent Information Processing”. The problem of the land-based satellite tracking telemetry and command (TT&C) resources scheduling is of importance to the development of aeronautic and space cause. The problem is a typical constraint optimal problem. It is related to the constraints of satellites and land-based satellite TT&C resources. It also relates to the visible relationships between satellites and land-based satellite TT&C resources. This problem has appealed to many researchers. Zhai and Tang consider the balance of each station and propose a balanced scheduling algorithm. However, they do not give a mathematic model for the problem and the proposed algorithm is prone to trap in a local optimal solution. Yang et al. study the satellite TT&C resources scheduling strategies by use of one of the discrete event system simulation methods, the Event Scheduling (ES) method, and propose the mathematical models. However, the models focus only on the conflict of individual ground stations. Gratch et al. investigate adaptive problem solver and take the problem of scheduling the Deep Space Network (DSN) 26-meter subnet as example. They formulate the problem. However, the formulation lets the time periods specifying all temporal intervals when a satellite can legally communicate with an antenna be the variables. The formulation does not consider the constraint that a satellite to be tracked and commanded by only a visible ground station and the priorities of orbits. This paper proposes a novel model, the mission oriented model, for the land-based satellite tracking telemetry and command (TT&C) resources scheduling problem. The model constrains a satellite to be tracked and commanded by only a visible ground station to make better use of ground stations. This paper also proposes a global optimization method based on the clonal selection operator to solve the problem.Authors have made researches on fields of evolutionary computation, such as immune clonal evolutionary algorithms and so on, and have applied these algorithms to many engineering problems, such as the multicast routing problem and so on.