Initial alignment of rotation modulation SINS based on improved open loop gyrocompass method

The initial alignment technology is one of the key technologies of inertial navigation, and its precision will directly affect the navigation results. Based on certain scheme, the Rotation-Modulation Strap-down Inertial Navigation System (RMSINS) can modulate the errors of inertial sensors; therefore, the precision of navigation system can be improved. But the errors of initial alignment of the system cannot be modulated. So it is essential to study on the initial alignment technology of rotation-modulation system and to find a proper alignment scheme for such systems. In this paper, especially aimed at single-axis RMSINS, the error models of the sensors are deduced and established. The open loop gyrocompass method is introduced and improved. The results of semi-physical simulation based on recursive least square algorithm prove that the alignment scheme provides high precision, rapid speed and valid effect. The research will have important value for the theoretical research of RMSINS and its engineering implementation.