Calibration of Airdata Systems Using Extended Kalman Filtering Technique

Abstract

One of the aims of air data systems is the determination of flight parameters angles of attack and angle of sideslip from measurements of local pressures and of local flow angles on wings or fuselage using a proper set of sensors. The active and integrated use of flight parameters in a full-authority flight control system imposes requirements for accurate and reliable air data, which are critical to maintain control. In this paper, a methodology based on the data fusion using Extended Kalman Filter technique is applied to dynamic maneuvers with rapid variations in the aircraft motion to calibrate angle of attack and angle of sideslip. The main goal of the investigations reported in this paper is to obtain online accurate flow angles from the measured vane deflection and difference pressures from probes sensitive to flow angles even in the adverse effect of wind or turbulence. The investigations are initially made on simulated flight data with wind and turbulence effects and it is showed that both alpha and beta estimates are accurate. The same procedure is then extended to flight test data of a high performance fighter aircraft. It has been shown using these results that sensor data fusion approach proposed in this paper is of great value in online implementation.