Abstract: A system and method for head tracking for a head worn display (HWD) includes head-frame and platform-frame IMUs providing high-rate pose data of the wearer's head and a mobile platform. An optical tracker estimates an optical pose of a camera oriented at fiducials based on a comparison of 2D image data captured by the camera (and portraying the fiducials within the image) and the known location of each fiducial in a 3D marker frame. The pIMU also provides low-rate, high-integrity georeferenced pose data of the mobile platform (e.g., in an earth frame). The head tracker provides low-rate, high-integrity absolute head pose solutions (e.g., user head pose in the earth frame) based on the georeferenced pose data and current high-rate head/platform pose data, updating the absolute pose solutions with high-rate updates based on combined extended Kalman filter propagation of the high-rate head and platform pose data with refined optical pose data.

Abstract: A power shaver having a hand-cranked dynamo is disclosed. The shaver includes a battery that can be charged by the hand-cranked dynamo, or from an alternating current adaptor that delivers charge from another battery, or from a charger that connects to a conventional source of alternating current. The shaver includes a foldable handle that allows a user to operate the dynamo, and folds against the body of the shaver when not in use. Indication lights located on the body of the shaver provide charging and status information to a user.