Hillcrest Laboratories, Inc.

Idhl Holdings, Inc.

Hua Sheng

Matthew G Liberty

Charles W K Gritton

Christopher David Roller

Bryan Austin Cook

A bias value associated with a sensor, e.g., a time-varying, non-zero value which is output from a sensor when it is motionless, is estimated using a ZRO-tracking filter which is a combination of a moving-average filter and a Kalman filter having at least one constraint enforced against at least one operating parameter of the Kalman filter. It achieves faster convergence on an estimated bias value and produces less estimate error after convergence. A resultant bias estimate may then be used to compensate the biased output of the sensor in, e.g., a 3D pointing device.

Methods, devices and systems for determining the zero rate output of a sensor

Methods and apparatuses for calibrating attitude-independent parameters of a 3-D magnetometer are provided. A calibration method includes storing and updating data related to a N&#xd7;9 matrix T and a N&#xd7;1 matrix U extended for each measurement with an additional row and an additional element, respectively, the additional row and the additional element being calculated based on values measured by the 3-D magnetometer for the respective measurement. The method further includes calculating analytically (1) a symmetric non-orthogonal 3&#xd7;3 matrix D representing scaling and skew of the 3-D magnetometer measured values and (2) a vector b representing bias of the 3-D magnetometer measured values, using the stored data and a singular value decomposition (SVD) method.

Apparatuses and methods for calibrating magnetometer attitude-independent parameters

Systems, devices, methods and software are described for mapping movement or motion of a 3D pointing device into cursor position; e.g., for use in rendering the cursor on a display. Absolute and relative type mapping algorithms are described. Mapping algorithms can be combined to obtain beneficial characteristics from different types of mapping.

3D pointer mapping

A bias value associated with a sensor, e.g., a time-varying, non-zero value which is output from a sensor when it is motionless, is estimated using at least two, different bias estimating techniques. A resultant combined or selected bias estimate may then be used to compensate the biased output of the sensor in, e.g., a 3D pointing device.

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Rockville, MD, United States of America

Hua Sheng