The geomagnetic field protects the Earth's atmosphere against charged particles from the solar wind. Rapid and long-term changes in the field are monitored by low-orbiting satellites and a global network of about 200 magnetic observatories. Field models, computed from these measurements, provide the direction and strength of the magnetic field at any desired location. Magnetometers (or a simple compass) can then be used to compute pointing directions, complementing the location information provided by the global positioning system (GPS).
Earth's magnetic field is used in a wide variety of applications. It is used to despin satellites, explore natural resources, survey property boundaries, point antennas and solar panels, conduct research, study Earth's tectonic history, and to navigate on land, sea, and air.
