<h2>AAS 99-137</h2>
<h2>Software-in-the-loop for Attitude Determination and Control System Using Simulink and Real-Time Workshop.                                        </h2>
<h4>I. Kim, J. Kim                                                                                                                                                                      </h4>
INHA University, Inchon, Korea                                                                                                                                            
<h2> Abstract </h2>
This paper presents the software-in-the-loop simulator called as SATellite SIMulator (SATSIM). The GNC laboratory at INHA University has been developing the SATSIM for last 4 years as an ADCS design verification tool. The SATSIM used the SIMULINK as a platform and the Real-Time Workshop to accelerate the execution speed of SIMULINK. The SATSIM consists of the environmental modules and the onboard software modules. The environmental modules simulate the real attitude dynamics, external environment and hardware components with the nonlinear characteristics. The onboard software modules include the attitude determination logics such as the Kalman filtering and vector observation technique, and the attitude control logics such as the PIID controller and he disturbance accommodating controller. Using the SATSIM, we verify the ADCS performance of Korea Multi Purpose Satellite (KOMPSAT) which is schedules to launch on July 1999.