An improved rotation scheme for Tri-axis rotational inertial navigation system

Rotating modulation technique is a mature method which has been widely used in the rotational inertial navigation system (RINS). A proper rotation scheme can greatly improve the position accuracy of the system. However, if the system is in angular motion, the modulation performance of the rotation scheme will be affected and improvements should be made. The modulation mechanism of a conventional rotation scheme based on tri-axis RINS in static base, which is called Scheme A in this paper, is analyzed firstly. Then the bad effects of system’s yaw angular motion upon the modulation performance are discussed and an improvement of the rotation scheme aiming at dynamic base is put forward after that. Simulations based on Matlab are conducted to demonstrate the effectiveness of the improvement. Vehicle experiments based on a real tri-axis RINS demonstrate that the improvement made on rotation scheme can reduce the maximum radical direction position errors by 0.6 n miles in 12 h roughly compared to the original unimproved scheme.