A New Fast In-Motion Coarse Alignment Method for GPS-Aided Low-Cost SINS

In this paper, a new fast in-motion coarse alignment method is proposed for a low-cost strap-down inertial navigation system (SINS) aided by the global positioning system (GPS). As compared with existing dynamic attitude estimation based initial alignment methods, in the proposed method, the constant attitude matrix from initial body frame to initial navigation frame is rapidly estimated, which results in improved alignment speed. Moreover, the time-varying attitude matrix from current body frame to initial body frame and gyroscope bias are jointly estimated based on a new constructed state-space model using the dynamic attitude estimation technique, and the resultant estimate and closed-loop calculation are utilized in the construction of vector observations, which improves the accuracy of coarse alignment. Experimental results illustrate that the proposed method has faster alignment speed and better alignment accuracy than existing state-of-the-art methods for GPS-aided low-cost SINS.