Tightly Coupled Integration Design for a Magneto-Inertial Navigation System Using Concurrent AC Magnetic Measurements

Recently, magnetic measurement-based pose estimation technology increasingly attracts the researcher's attention as a complementary navigation technology. The main purpose of introducing magnetic fields is to secure a reliable pose estimation in non-line-of-sight (NLOS) environments where satellite navigation is unavailable or vision, lidar, and other auxiliary sensors that make use of signals of opportunity cannot provide robust performance. Unlike the previous researches, this paper proposes a new method for implementing the integrated magneto-inertial navigation system based on three-dimensional AC magnetic field vectors from concurrent measurements. Instead of taking an independent pose estimation result from the magnetic positioning system, the proposed algorithm investigates a direct integration scheme that employs the raw magnetic field vectors from concurrent measurement sources. A theoretic formulation is developed, which enables to establish the integrating framework with the INS mechanization. The presented algorithm is validated through trajectory experiments in a small-scale test platform. As a result, it is demonstrated that the computational efficiency is substantially enhanced to enable real-time implementation of the proposed magneto-inertial navigation system, while the estimation performance has sub-centimeter accuracy in a 3D dynamic experiment.