Data Collection Requirements for the World Magnetic Model

The World Magnetic Model (WMM) is a spherical harmonic model of the Earth's main magnetic field and its secular variation, developed by NOAA National Centers for Environmental Information and the British Geological Survey and updated every five years. It is the standard geomagnetic model for navigation, attitude and heading referencing of the U.S. Government and several other national and international organizations. Unlike other reference models such as the International Geomagnetic Reference Field (IGRF), the WMM has to meet a set of performance specifications. This entails that the WMM error has to be regularly assessed over the five-year modeling cycle, to make sure that the specification continues to be met. It also entails specific requirements on the quality of the data used to infer the WMM. While currently available Low Earth Orbit (LEO) satellite data are of sufficient quality for deriving a WMM, very few studies have attempted to determine the minimum data collection requirements for the WMM or similar geomagnetic reference models. In this presentation, we will report on various simulations aimed at better understanding such requirements. Results from these simulations will inform future geomagnetic data collection efforts, both space-based and ground-based. We will also report on the upcoming WMM2020, to be released in December 2019.