Geomagnetic matching algorithm based on Hidden Markov Model

In order to improve the locating precision of the inertial navigation system in regions with significant geomagnetic characteristic, and realize the geomagnetic aided navigation in regions with insignificant geomagnetic characteristic, a geomagnetic matching algorithm based on HMM (Hidden Markov Model) is proposed. Firstly, the approach took INS position error as its hidden state variable and geomagnetic value as the measurement, and an HMM model for GM(geomagnetic matching) is established. Then, with the given model, an HMMGM algorithm using Viterbi algorithm is designed and implemented to estimate the position error in INS. The simulation results show that geomagnetic aided navigation can be implemented using HMMGM. It is showed that the HMMGM algorithm can significantly improve the positioning error compared with EKF algorithm, and the positioning error of the integrated navigation system is approximately 50 m.