An algorithm based on square root unscented Kalman filter(SRUKF) was presented to solve the aeroengine health parameter estimation problem.The SRUKFmethod could be applied to addresses the estimation inaccuracy of linear Kalman filter and the filtering divergence problem caused by error covariance matrix non-positive in general unscented Kalman filter.Amethod for improving the filtering convergence rate and stability was developed according to the residual vector.The results obtained from gradual and abrupt fault diagnostic simulation show that

SRUKFfeatures rapid convergence

higher stability and accuracy

making it become an efficient estimation and fault diagnosis method for health parameters of gas path components in aeroengines.