Satellite Simulator and Model Based Operations in Quasi Zenith Satellite-1 (QZS-1) development, verification and operations
- Paper number
IAC-08.B2.2.4
- Author
Dr. Noriyasu Inaba, JAXA, Japan
- Coauthor
Mr. Hidemi Hase, Japan
- Coauthor
Mr. Hiroyuki Miyamoto, JAXA, Japan
- Coauthor
Mr. Koji Terada, Japan
- Year
2008
- Abstract
Complexity of a space system makes it difficult to design a reliable system and to verify it. Model based designing methods and satellite simulators as elements of the methods are recently used in designing and verification of space systems. A satellite simulator is widely used in development, verification and operations of the first satellite of Japanese regional satellite navigation system (Quasi Zenith Satellite -1). The simulator consists of functional models of onboard computer and flight software as a core, and mathematical models of peripheral components such as sensors/actuators and an environment to simulate functional, dynamical and thermal behavior of the satellite in space. Since, the QZS-1’s development schedule is very short as a R&D satellite, approximately forty months from starting the basic design to the launch. An onboard attitude control software is newly designed to implement yaw-steering attitude control using a star tracker as the primarily attitude sensor to accommodate unique inclined elliptical geosynchronous orbit. Effective and through software verification covering operational envelopes is conducted using the satellite simulator. In terms of operations, operational procedures are organized and prepared in layered manner in conjunction with the operational modes to operate the system by minimun ground crew. By using operational modes and transition diagram of the system, subsystems and components, crew can easily choose appropriate procedure files depending on the satellite’s current state and the goal state. Operational modes are defined related with state mode transition diagrams that are used in hardware development phase. The operational modes are not always required to describe all the characteristics of the system, but to describe exact behaviors of the system within verified and authorized operational envelope. The operational modes and transition diagrams are used as source information to develop mathematical model of the satellite simulator to be used for operational flow design and verification. The simulator is also used as an operation-training tool before flight operation, and as a tool for monitoring and anomaly analysis in the flight operations.
- Abstract document
- Manuscript document
IAC-08.B2.2.4.pdf (🔒 authorized access only).
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