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A multi-mission GEO satellite, COMS has three payloads including Ka-band communications, GOCI, and MI. COMS SGCS is the only system for monitor and control of the satellite in orbit. In order to fulfill the mission operations of the three payloads and spacecraft bus, COMS SGCS performs the following functions such as reception and processing of telemetry data via S-band link, planning and transmission of telecommand, tracking and ranging of the satellite, control and monitoring of SGCS equipment, analysis and simulation of the satellite, processing and analysis of flight dynamics data, and mission scheduling and reporting. By the proper functional allocations, COMS SGCS is divided into five subsystems such as TTC, ROS, MPS, FDS, and CSS. COMS SGCS is linked with MSC, KOSC, and IDACS for satellite related data exchange. The software in the COMS SGCS is designed using the object-oriented methodology and implemented using Microsoft C# .NET environment on Intel microprocessor based computers. The hardware in the COMS SGCS includes 13-m S-band mono-pulse Cassegrain antenna and RF/BB equipment. In this paper, development of the COMS SGCS is described with respect to system functional allocations, software and hardware design, system implementation, and system test.

The modeling of satellite multi-body dynamic is quite complicate process. In developing satellite simulator, it’s proper to use multi-body dynamics in modeling satellite attitude dynamics. We will introduce the attitude dynamic module that is able to cover various satellites and operational phases. This approach may improve portability of satellite modeling. The generalization of multi-body attitude dynamics model can be used to analyze orbit and attitude dynamic of satellite. It is very useful for various satellites system and applying to other system with several parameters change.

In this paper, a method of station keeping strategy using relative orbital motion and numerical optimization technique is presented for geostationary spacecraft. Relative position vector with respect to an ideal geostationary orbit is generated using high precision orbit propagation, and compressed in terms of polynomial and trigonometric function. Then this relative orbit model is combined with optimization scheme to propose a very efficient and flexible method of station keeping planning. Proper selection of objective and constraint functions for optimization can yield a variety of station keeping methods improved over the classical ones. Nonlinear simulation results have been shown to support such concept.

Satellite system has lots of fault causes. For some communications satellite systems, fault management and data preservation are required to exchange data continuously and provide broadcasting service. In this paper, we have proposed fault management of satellite system using penalty method, data buffer and recovery manager. The penalty manager imposes penalty according to fault degree and manages fault quantitatively. Data Buffer has the function to store data in fault situation and prevent data damage. Recovery manager performs system monitoring and to operates recovery process in fault situation. Proposed method is fundamental concept of the architectural characteristics and enhances satellite fault management performance. This capability permits the satellite to detect and correct some of its own failures autonomously. Also, the effect of penalty method and data buffer on fault management design has been discussed.

The simulation of LEOP operations was presented. A generic software satellite simulator was used for the analysis and verification of LEOP operations. A specific spacecraft model was implemented in the simulator for the LEOP operation scenario. The satellite model includes spacecraft subsystems and the flight dynamics models. LEOP simulation was performed by the stored relative time command set in the on-board flight software that was implemented on the simulator. The simulation started from the separation of a launch vehicle and executed solar array deployment, deployment test, and activation of sun point mode. Simulation results of earth searching operation and orbit adjusts maneuver are also provided.