In July 2000, a new potential fields satellite was launched and is currently measuring the earth's gravity and magnetic fields (the latter down to 0.1 nT). The satellite, called CHAMP (CHAllenging Mini-satellite Payload), will be providing high accuracy crustal magnetic field data of the earth for wavelengths of about 300–3000 km until about 2005.

Previous magnetic satellites have been reviewed by Ravat and Purucker (TLE, 1999) who found that an excellent comparison could be made between the long wavelength component of the DNAG magnetic field (>500 km) covering North America and the Magsat satellite field. Magsat was limited...

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