Effect of Non-orthogonality in Dual-axis Gimbal on Rotational Inertial Navigation System

In this paper, we analyze the effect of nonorthogonality in a dual-axis gimbal constituting a rotational inertial navigation system (RINS) on the navigation performance. The RINS alleviates navigation errors caused by sensor errors through periodic attitude modulations. Hence, it is robust to the GNSS-denied environments. However, the rotations themselves cause new error factors, where the most common one being the non-orthogonality between the gimbal rotation axes. Therefore, in this paper, the navigation error additionally generated by the non-orthogonality of the dual-axis gimbal during the rotational motion of the RINS is analyzed. The results show that the non-orthogonality directly affects the N-axis attitude error, and hence consequentially the E-axis velocity and position error as well.