Improving the Accuracy of Initial Alignment of Strapdown INS with the Help of Gimballed INS

An inertial measurement system (IMS) for space launch vehicles including a gimballed IMU (GIMU) and a strapdown IMU (SIMU) is considered. A technique for SIMU initial azimuth alignment with the help of GIMU data is proposed. Two variants of the technique are analyzed. For both variants, the basic equations and the results of error analysis obtained by mathematical simulation are discussed.