Abstract:

A novel piece-wise fast alignment method for strapdown inertial navigation system (SINS) stationary alignment using lifting wavelet is presented. First, the fine horizontal alignment is executed. After the fine horizontal alignment, a lifting wavelet algorithm is utilized to de-noise the output of the gyros, and the azimuth mis-alignment angle is rapidly calculated Theoretical analysis and practical experiment show that the lifting wavelet algorithm is effective to the de-noising of fiber optic gyro. Compared with the method using Kalman filter in the whole process of the alignment, this method has the same steady state accuracy, but in the process of the fine azimuth alignment, the mechanical arrangement of SINS is not needed, and the time of fine alignment can be shortened to 30 s or so. This method makes up the defect that the convergence speed of the azimuth misalignment angle is slow, and accelerates the initial alignment process.