The Application of Modified Output Error Method on ALFLEX Flight Data

A modified output error method was developed by the authors, the application of which on YF16 aircraft has been reported at the ISIP2000. In this paper, we applied the method on ALFLEX (Automatic Landing Flight Experiment) flight data supplied by NAL (National Aerospace Laboratory) /NASDA (National Space Development Agency of Japan) for estimating the aerodynamic characteristics and the input control histories. As the result, the time histories of the altitude, the total velocity, and Euler angles are very precisely estimated like the same as our previous applications. Next, we tried to verify the performance in more detail, particularly for high frequency characteristics. The applied data include the effect of intentional control surfaces′ vibration inputs. The result shows that the method is also effective to these high frequency variations of variables.