Use of State Estimation to Calculate Angle-of-Attack Position Error from Flight Test Data

摘要

This thesis determined the position errors of an aircraft's angle-of-attack (AOA) sensor using state estimation with flight test data. The position errors were caused by local flow and upwash and were found to be a function of AOA and Mach number. The test aircraft used in this project was a T-38A Talon supersonic trainer from the USAF Test Pilot School configured with a Vought yaw and pitch system noseboom and an internal Aydin-Vector data acquisition system (DAS). The position errors were found by calculating the true AOA using equations of motion and DAS parameters. The data from the DAS were noise corrupted and had to be filtered. This was accomplished using state estimation in a Kalman filter. The estimated AOA was compared to the measured AOA from the noseboom sensor to obtain the position error. Accurate position errors were obtained, even in dynamic maneuvers. This method should be considered in future AOA error testing. The method was accurate enough to identify a hysteresis error in the T-38's AOA sensor of +/-0.5 degrees, which was confirmed by ground calibration.