Position sensing is of core importance to any space craft. Each satellite carries sensors which measure the amount of visible light, thermal (infra-red) radiation, and radiation from other parts of the electromagnetic spectrum coming from the earth. The sensors then determine the exact location of the satellite and the orientation in the space with respect to the earth, the reference inertial frame. The subsystem uses the following sensors:
The sun sensor determines the satellite’s body angle with respect to the sun. Spacecraft magnetometers are used for attitude determination using the local geomagnetic field as the sensing parameter. Also, the satellite can be rotated according to the commands received through a combined form of gyroscopes and accelerometers.