Patent ID: 7920985

Claim:
An inclination calculation apparatus that computes an updated new inclination vector of an input device in real time, said input device having an acceleration detector capable of consecutively detecting acceleration simultaneously in at least two axial directions, comprising: preliminary data generation programmed logic circuitry configured to consecutively generate preliminary data which represents a current inclination vector which is uniquely determined from current acceleration data obtained from the acceleration detector; and inclination calculation programmed logic circuitry configured to regularly consecutively compute updated new inclination vectors in real-time based on a previously computed inclination vector, a current inclination vector and an effectiveness value which represents a degree to which a direction of a previous computed inclination vector must be made closer to the direction of the current inclination vector, wherein the effectiveness value is used during each computation to result in a direction for the updated new inclination vector which more accurately reflects an actual inclination of the input device at the time the acceleration data is acquired.