Patent ID: 7400142
Filing Date: 2008-07-15
Classification: G01R

Abstract:
1. A system for dynamically compensating for magnetic anomalies due to the proximity of ferromagnetic objects or electric motors, comprising: a parallelopiped; three-axis magnetometers each having three orthogonal axes, each of said magnetometers measuring magnetic field thereat and supplying a corresponding output, located at selected corners of said parallelopiped, said magnetometers having their three orthogonal axes aligned with the three orthogonal axes of the other magnetometers; a processor coupled to the outputs of said magnetometers to derive a magnetic anomaly gradient vector in terms of a difference in sensed magnetic field due to the presence of an anomaly; and, an instrument for which heading is an output including a compass, said magnetic anomaly gradient vector coupled to said compass to compensate said compass for said magnetic anomalies.