INS/GNS Integrated Navigation on Small Area

In order to reduce the navigational errors caused by the model factors and achieve high-precision navigation in small-scale areas, the original Earth’s main magnetic field model created by the dipole is replaced by rectangular harmonic model as the INS/GNS integrated navigation system observation equation. At the same time, with the complex magnetic interference in the actual environment and its unknown statistical properties, to avoid calculating the Jacobean matrix in literalizing the observation equation, the UKF algorithm is adopted in the design of a nonlinear time-varying noise estimator to reduce magnetic interference and improve the accuracy of navigation. The simulation results show that the algorithm greatly improves the accuracy of the integrated navigation. It can be used in noisy environments.