The application in SINS´s initial alignment based on combination of LQ optimal control and Kalman filter

The traditional Kalman filter can be used to estimate the misalignments. However, not only such fine estimation´s duration is very long, but also the precision can not be guaranteed every time. The linear-quadratic (LQ) optimal control has the characteristic of the closed-loop feedback control. If a admissible control law is used, it can make the control system run in rule of the predetermined request movement. This paper provides a new method which combines LQ optimal control with kalman filter in the fine alignment of the strapdown inertial navigation system(SINS). Through the simulation, it shows that this method can accomplish the fine alignment effectively which spends less alignment duration and provides better performance than the traditional method only using kalman filter.