Geomagnetism aided inertial navigation system

Geomagnetic field is one of the geophysical fields of the Earth and can be used to limit the error accumulation of the inertial navigation system (INS). A geomagnetic aided navigation system is proposed in the paper. Two alternate processes are designed in the system - the match and the filter. In the former part, a contour constraint based correlation method is used to eliminate the initial position error of the system, greatly reducing the computational burden of the whole system. Heading error can be effectively estimated by an iterative closest point (ICP) algorithm. In the filter part, a linear Kalman filter is designed to update INS continuously. Position measurements are given by a ldquonearest pointrdquo principle and the position error caused by this principle does not accumulate with time, which leads to a nearest point based Kalman filter (NPKF). Geomagnetic anomaly maps are used to test the proposed system, and good performance is observed.