Linearized In-Motion Alignment for a Low-Cost INS

An accurately linearized in-motion alignment with a large heading error is proposed for a low-cost inertial navigation system with the aiding of global positioning system. The linearization is designed for both the coarse and the fine stages in the local level frame. A criterion is constructed to determine the time to switch the alignment from the coarse stage to the fine one automatically. A vehicle test demonstrates that the proposed alignment converges fast and accurately.