A portable computing device is disclosed which may include a base element, a lid element, a first motion sensor, a second motion sensor, a processor, and an eye tracking system. The first motion sensor may be disposed in the base element. The second motion sensor may be disposed in the lid element. The processor may be configured to control the first motion sensor to detect first motion information, control the second motion sensor to detect second motion information; and determine final motion information based at least in part on the first motion information and the second motion information. The eye tracking system may be configured to determine a gaze position of a user based at least in part on the final motion information, wherein the processor is further configured to execute one or more control processes based at least in part on the determined gaze position meeting a predetermined condition.