Woodbury, Timothy, Arthurs, Frank, and Valasek, John, "Flight Test Results of Observer/Kalman Filter Identication of the Pegasus Unmanned Vehicle," AIAA-2015-1481, Proceedings of the 2015 AIAA Atmospheric Flight Mechanics Conference, Kissimmee, FL, 8 January 2015.
The paper is free to download here:
Flight Test Results of Observer/Kalman Filter Identication of the Pegasus Unmanned Vehicle