Specific force integration algorithm with high accuracy for strapdown inertial navigation system

The traditional method of solving the specific force integral term in a strapdown inertial navigation system is to approximate and then integrate. In order to eliminate approximation error of the traditional method, a new specific force integration algorithm is developed in this paper. First, an analytical expression for the specific force integral term, which provides an exact solution for velocity rotation error compensation, is obtained under constant angular rate/specific force. Next, from the definition of specific force we analyze the causing reason of sculling error effect, and without changing the analytical expression we determine a reasonable correcting measure in which sculling error can be calculated using existing algorithm. Finally, a fourth-order navigation algorithm for the specific force integral term is designed and compared with the traditional one in performance. Advantages of the new specific force integration algorithm over the traditional one, including the significantly improved accuracy and good overall performance, have been strongly demonstrated by simulation test results under typical sculling motion and highly-dynamic environment.