Abstract: The extended Kalman Filter and fixed-interval Smoother (EKF/S) and Square-Root Information Filter and Smoother (SRIF/S) for flight data compatibility check of two kinds of supersonic aircraft are presented. In order to get high accuracy and computation efficiency, the modified SRIF/S is proposed by exploiting some features of model. The results of simulation and actural flight data computation show that these two methods can give satisfactory result and the modified SRIF/S not only imprives the numerical stability, but also reduces significantly the computation and storage requirement and is more efficient than EKF/S.

Key words: extended Kalman filter, square-root information filter and smoother, flight data compatibility check, flight test