Disclosed herein are apparatus and methods for measuring error associated with the rotation of bearings (50) used within a pointing device (11) on board a space-based platform. The apparatus includes inductive, or “eddy current,” proximity sensors (1000) adapted for measuring the positioning of bearing...http://www.google.de/patents/US7107168?utm_source=gb-gplus-sharePatent US7107168 - System for measuring the effect of bearing errors in an active device
