A mobile station and unattached work area is used with an electronic pen, which includes a transmitter, such as an acoustic transmitter. The mobile station includes a receiver that receives signals from the transmitter and orientation sensors that detect movement of the mobile station. The position of the receiver is calibrated with respect to the unattached work area. Data from the orientation sensors is received when the mobile station, and thus, the receiver is moved with respect to the work area. A transformation matrix is generated based on the data from the orientation sensors, which can be used to correct for the movement of the receiver. The position of the transmitter in the electronic pen is calculated and mapped based on received signals and the transformation matrix and the mapped position is then displayed.