Recently the MagQuest competition on improving the measuring of the Earth’s magnetic field announced that the contestants in the final phase have now moved on to launching their satellites within the near future. The goal here is to create a much improved World Magnetic Model (WMM), which is used by the World Geodetic System (WGS). The WGS is an integral part of cartography, geodesy and satellite-based navigation, which includes every sat nav, smartphone and similar with built-in GNSS capabilities.

Although in this age of sat navs and similar it can seem quaint to see anyone bother with using the Earth’s magnetic field with a compass, there is a very good reason why e.g. your Android smartphone has an API for estimating the Earth’s magnetic field at the current location. After your sat nav or smartphone uses its magnetometer, the measurements are then corrected so that ‘north’ really is ‘north’. Since this uses the WMM, it’s pertinent that this model is kept as up to date as possible, with serious shifts in 2019 necessitating an early update outside of the usual five-year cycle.

Goal of the MagQuest competition is thus to find a method that enables much faster, even real-time updates. The three candidate satellites feature three different types of magnetometers: a scalar-vector magnetometer (COSMO), a nitrogen-vacancy (NV) quantum sensor, and the Io-1 satellite containing both a vector fluxgate and atomic scalar magnetometer.

The NV quantum magnetometer is quite possibly the most interesting one, featuring a new, quantum-level approach for magnetic sensing. This effectively uses a flaw in a diamond’s carbon matrix to create a quantum spin state that interacts with magnetic fields and can subsequently be read out. The advantage of this method is its extreme sensitivity, which makes it an interesting sensor for many other applications where measuring the Earth’s magnetic field is essential.