Carrier angular motion isolation and modulation method of dual-axis rotation inertial navigation system

In traditional dual-axis rotation inertial navigation system (DRINS), the inertial measurement unit (IMU) is rotated regularly to modulate the inertial device error based on the carrier coordinate system. However, irregular carrier angular motion of the carrier will affect the modulation effect. Aiming at this problem, the mathematical relationship among IMU sensitive data, carrier attitude and dual-axis rotation angles is analyzed. Then a method of carrier angular motion isolation based on dual-axis rotation mechanism is proposed. On this basis, aiming at the problems of difficulty in control, cumulative control error and measurement delay of angular rate of rotation axis existing in angular rate control method in carrier angular motion isolation, a dual-axis rotation isolation and modulation method based on angle control is proposed. The theoretical analysis and simulation result based on vehicle test data show that the proposed method can isolate the carrier angular motion effectively. Compared with traditional rotation modulation method, the modulation effect of the proposed method is significant, and the navigation position error could be reduced by more than 50% in most surface motion applications. © 2020, Science Press. All right reserved.