Attitude Determination of LAPAN-A3 Satellite based on Magnetometer and Sun Sensor

The primary objective of a remote sensing satellite is to provide precise information about the earth’s surface to the ground control center. In order to avoid severely disrupted or failed imaging operations, the attitude determination and control system (ADCS) represents a crucial task. LAPAN-A3, the third satellite developed by LAPAN, was designed for a specific experimental mission to observe Indonesian territory. LAPAN-A3 relies on its star sensor as the main attitude determination due to its accuracy. Nevertheless, star sensors become susceptible to vulnerabilities when facing a bright celestial object. This study presents an alternative approach by utilizing a combination of sun sensors and magnetometers. By calculating the matrix rotation between the sun and magnetometer data onboard the satellite, with the sun position model Almanac and IGRF, the satellite attitude can be determined. From the test result, the matrix rotation method enables the computation of quaternions, which in turn allows for the determination of the satellite’s yaw, pitch, and roll angles. This research shows that the proposed method can achieve an accuracy of $0.37^{\circ}, 0.33^{\circ}$, and -1.07° with a standard deviation of $1.89^{\circ}, 1.08^{\circ}$, and 1.2° for yaw, pitch, and roll angle, respectively.