Onboard geomagnetic field generation module for CubeSat attitude control simulations

Abstract

In recent decades, employing small satellites in low earth orbit (LEO) has a growing trend. Generally, they are equipped with magnetic actuators, e.g., magnetorquers (MTQs) and reaction wheels (RWs), that work together to perform a variety of operation modes. The LEO satellites functionally experience the Earth’s magnetic field more than other spacecrafts, and the B-dot control scheme inherently utilizing the geomagnetic field is unanimously applied among small satellites mainly for the maneuvers of attitude detumbling and RW momentum desaturation. In this paper, perceiving the need for a geomagnetic field generation module to provide a LEO environment when developing CubeSat’s ADCS, an integrated “Onboard Geomagnetic Field Generation Module (OGFGM)” consisting of an orbit propagator, an IGRF model, and coordinate transformations is proposed, which can be flexibly and conveniently embedded in the relevant structured frameworks (e.g., model-in-the-loop (MIL)) to render the in-orbit geomagnetic conditions, enabling the dynamic magnetic field simulations required for ADCS research and design (R&D) to be performed in a real-time and coherent manner. In this work, the computed local geomagnetic fields ( B NED ) of three orbit types (e.g., ISS, Polar, and Equatorial) are compared with the BGS (British Geological Survey) website IGRF calculator, the integrity of respective geomagnetic field conversions during the MIL simulation is examined, and the B-cross attitude control scheme adopting mechatronics engineering strategy is simulated in the MATLAB/Simulink environment showing a substantial enhancement in actuation effort.