<P>PROBLEM TO BE SOLVED: To provide an inertial sensing input apparatus and method usable on a plane or in free space, capable of compensating an unconscious rotation caused by a human operation, and preventing interferences caused by electronic noises generated from an accelerometer. <P>SOLUTION: The inertial sensing input apparatus comprises an accelerometer and a gyroscope 12. The input apparatus is operable either on a plane or in a free space by selectively operating the input apparatus in a two-dimensional mode or a three-dimensional mode. In the two-dimensional mode, the gyroscope 12 is activated to detect a rotation of the input apparatus 10 caused when the input apparatus 10 is moving and thus generate an angular velocity signal correspondingly for compensating an unconscious rotation caused by a human operation. Also, interferences caused by electronic noises generated from the accelerometer or an electric circuit are removed by thresholding and iterative averaging algorithms, so that the inertial sensing input apparatus is freed from the shortcomings of prior-art inertial input apparatus and can be used smoothly and naturally. <P>COPYRIGHT: (C)2008,JPO&INPIT 
INERTIAL SENSING INPUT APPARATUS AND METHOD