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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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You are invited to hear
Montgomery Knight 317 @ 3:30pm
Estimating the attitude of a rigid body has applications to many systems, including spacecraft, inertial navigation of aerial vehicles (both piloted and uninhabited), underwater vehicles, and robotic systems, to name a few. The first known algorithm for attitude estimation dates back to 1970, which is based on the famous quasi-linear (extended) Kalman filter algorithm. This algorithm has been the workhorse for most systems that require attitude knowledge. Due to the inherent nonlinearities associated with attitude estimation, numerous nonlinear estimation techniques have been developed since that time. Some have shown global, or near-global, convergence while others focus on robust methods to handle model errors or non-Gaussian characteristics. Much less attention has been given to the problem of estimating vector state coordinates with respect to the attitude state coordinate frame. This work presents a new error definition in which vector error quantities are defined using elements expressed in a common frame. It is claimed here that the new error definition is more grounded theoretically than the usual error definition used by all other techniques. Examples in spacecraft attitude estimation are given to show the advantage of the new error definition over the standard error definition.
Dr. John L. Crassidis is the CUBRC Professor in Space Situational Awareness in the Department of Mechanical and Aerospace Engineering at the University at Buffalo (UB), State University of New York. Before joining UB in 2001, he held previous academic appointments at the Catholic University of America and Texas A&M University. He also held a position as a NASA Postdoctoral Research Fellow at Goddard Space Flight Center, where he worked on a number of spacecraft. Currently, he is Director of UB’s Center for Multisource Information Fusion, which is the only dedicated university data fusion center in the country. It is involved in basic research and developmental programs through various government laboratories, companies and university partners. He is also Director of UB’s Nanosatellite Laboratory. Dr. Crassidis is a Fellow of the American Astronautical Society, and a Fellow of the American Institute of Aeronautics and Astronautics.
