In this study, external magnetic fields measured by the magnetometer sensors are considered. For low-Earth orbiting (LEO) satellites, there are variety of magnetometers available off-the-shelf commercially. Their noise levels differ based on the mission goals of the satellites and technological advances. Earth's geomagnetic field predicted by the geomagnetic field models is used for satellite attitude control. Any deviations from the model fields, caused by the external sources such as magnetic storms, are treated as magnetometer noise or bias. This may prevent the determination of the magnitude of the effects from the external sources correctly. This study aims to reveal the magnitude of the geomagnetic field variations due to the magnetospheric storms obscured by the magnetometer noise level used in the attitude control systems by implementing a range of magnetometer sensor noise levels on the simulation of the satellite's rotational motion for the selected geomagnetic storm events.