SINS initial alignment using wavelet de-noising method for aircraft navigation

The error in the initial attitude determination is one of the most crucial sources of error for accurate inertial navigation. Estimation of the initial attitude angles accurately is the guarantee of precise determination of the position, velocity and attitude of a moving platform. For military aircrafts, the high precision and short time of initial alignment are key requirements. The required inertial signals (accelerometer specific force and gyro rates) are buried in high frequency measurement noise. When the aircraft engine is power on, the high frequency noise is introduced due to engine vibration and other disturbances. Kalman filter have been extensively used for initial fine alignment of Strapdown Inertial Navigation Systems (SINS). In this paper, Multi-resolution wavelet de-noising (MRWD) method is proposed to eliminate the high frequency noise from inertial sensor measurements before using for initial fine alignment. The proposed method is tested using real data sets collected when vehicle engine was power on. It has been observed that the accuracy of initial alignment can be improved through the proposed method.