Some results of ATTAS flight data analysis using maximum likelihood parameter estimation method

The maximum likelihood parameter estimation method for13; nonlinear systems is applied to estimate from flight data a13; at a few selected flight conditions the aerodynamic derivates of the DLR research aircrafts ATTAS (Advanced Technologies Testing Aircraft System). For this purpose, the coupled equations of aircraft motion pertaining to the longitudinal and lateral direction motion in the wind axis system and an aerodynamic model in terms of non-dimentional derivatives are employed. In addition, details are also provided of the specially carried out flight manevurves whih enable seperate estimation of the two pitch damping derivatives due to pitch rate and rate of change of angle-of-attack from flight data