INS in-motion alignment for land-vehicle aided by odometer

In-motion alignment plays an important role in improving the maneuvering capability of the carrier, which allows the initialization of an inertial navigation system (INS) while on moving. Different from stationary alignment, the implementation of in-motion alignment usually needs an external navigation device such as GPS or odometer to provide vehicle dynamic information to compensate and correct the INS errors. In the field of land navigation, odometer aided in-motion alignment is widely adopted due to its full self-contained characteristic. In this contribution, odometer error is modeled comprehensively as a part of system dynamic model, and the displacement incremental matching method is proposed to finally realize the integration of odometer and INS. Besides, effective fault diagnosis is proposed to evade odometer measurement errors caused by the complicated environment. The effectiveness of the proposed method is verified through ground based alignment experiments. The results show that the heading error is less than 0.05° after ten minutes initial alignment which is equivalent to that of the stationary alignment.