A fluxgate magnetometer is a device that measures the intensity and orientation of magnetic lines of flux . Fluxgate magnetometers have been used by robotic space probes to analyze, map and monitor the magnetic fields of the earth and other planets. They are also used in geological prospecting, aerospace navigation, underwater navigation, land navigation and submarine detection.
The heart of the fluxgate magnetometer is a ferromagnetic core surrounded by two coils of wire in a configuration resembling a transformer. Alternating current ( AC ) is passed through one coil, called the primary, producing an alternating magnetic field that induces AC in the other coil, called the secondary. The intensity and phase of the AC in the secondary are constantly measured. When a change occurs in the external magnetic field, the output of the secondary coil changes. The extent and phase of this change can be analyzed to determine the intensity and orientation of the flux lines.
The techology is sometimes used in a comprehensive robot guidance system that operates on the basis of external magnetic field s. In such a system, navigation is guided by continuous analysis of the intensity and direction of the flux lines within the robot's work environment. Here's how it works: An artificial external reference field is generated by placing strong direct current ( DC ) electromagnets at various points in the robot's work environment. The robot controller stores data concerning the resulting flux field. For each point in the work environment, the magnetic field has a specific intensity and the flux lines run in a specific direction. Based on this information, the robot can locate its position and orientation at all times and navigate along programmed paths.
Fluxgate magnetometers are usually employed in conjunction with other location and navigation methods such as the Global Positioning System ( GPS ).