A method of establishing aeroengine on-board adaptive model was proposed based on improved hybrid Kalman filter (IHKF). The output of nonlinear on-board engine model (NOBEM) was regarded as the steady-state basic model of piecewise linear Kalman filter(PWKF)

while its performance deterioration factor was regarded as the augmented state vector of PWKF for on-line estimation

and fed back to NOBEM for on-line updating. In addition

the switching logic of work mode was established

which could make the IHKF work better. By applying this method to a turbofan engine

a series of simulation results show that the model can always match the actual engine in the whole flight envelope

under different engine states and severe performance deterioration

thus meeting the needs of practical applications.