The enhancement of aircraft parameter identification using linear transformations

An approach is developed to identify the equations of motion of an aircraft using linear transformations. The equations of motion are transformed into the phase variable form, the identification is carried out in the phase variable domain and transformed back into the equations of motion form to get the stability and control derivatives. This identification procedure is very useful for the identification of the stability and control derivatives of an aeroelastic airplane. The accuracy of stability and control derivatives obtained through a phase variable transformation is verified by comparing the results of this procedure with the results obtained from the identification in the equations of motion form for the same data on the USAF Total In-Flight Simulator (TIFS). The phase variable method of identification was felt to yield results as accurate as the results obtained from the identification in the equations of motion form.