Effect of Magnetorquer Activity on the Measurement of Earth's Magnetic Field in LAPAN-A3 Satellite

In 2021, Indonesia's National Institute of Aeronautics and Space (LAPAN) become part of the National Research and Innovation Agency (BRIN), LAPAN develops and operates three earth observation satellites to improve the country's monitoring. LAPAN-A3, the third satellite developed by LAPAN, had a scientific mission to measure the earth's magnetic field by using a magnetometer sensor. However, the magnetometer onboard satellite not only measures the strength and direction of the earth's magnetic field but also a disturbance field induced by spacecraft electronics. Moreover, to avoid severely disrupted missions causing attitude error, the satellite depends on its subsystem to maintain its accuracy by using magnetorquer for correction. To exclude the disturbance of the magnetic field produced by the electronics, two magnetometers are operated. However, the LAPAN-A3 satellite only utilizes one magnetometer, hence it has a different approach. In consequence, the effect of magnetorquer activity on the measurement of the earth's magnetic field in the LAPAN-A3 Satellite has to be analyzed. In this research, a pseudo-inverse method is used to fix the difference in magnetometer data due to the changing of current in the magnetorquer on the LAPAN-A3 satellite. The method's result is a matrix function with its residual in each 3 magnetometer's axis. A change of 1 rnA in the X magnetorquer will give -43.2803 nT in the X direction, -45.9198 nT in the Z direction, and -0.8086 nT in the Y direction. It can be seen that by using pseudo-inverse, the magnetometer measurement can be corrected.