Abstract:

Underwater vehicle localization method based on geomagnetic anomaly inversion is proposed for solving the problem that the underwater geomagnetic map is not easy to make. In this method, underwater geomagnetic anomaly can be viewed as a magnetic dipole target. The vehicle position relative to the target is determined by the magnitude of its magnetic field and gradients, which are measured using ten single-axis magnetometers strapped on the vehicle. The relationships between magnetic field magnitude, gradients and vehicle attitude are studied theoretically and simulated numerically, and at the same time its effect on localization precision is also analyzed. These results show that the magnetic field magnitude is not almost influenced by vehicle attitude variation but the effect on its gradients are obvious. However, the distance between underwater vehicle and magnetic target does not almost vary with attitude angles. A novel method to calculate vehicle attitude variation by target magnetic moments is put forward and is studied theoretically and simulated numerically. The results show the calculating precision for the method is higher in principle, which can be used to detect attitude variation of underwater vehicles.