A compact vectorized magnetometer for measuring Earth's magnetic field in space

The World Magnetic Model (WMM) is a model of Earth’s magnetic field used for navigation. Its development relies in part on the use of magnetic field measurements from space, such as from the European Space Agency’s Swarm mission. Given that the Swarm mission has a limited lifetime, alternative approaches are required to provide sufficient data to maintain and update the WMM. For this purpose, we have developed a compact vectorized rubidium magnetometer that will be flown on a CubeSat mission. Here, a scalar rubidium Mz magnetometer is vectorized by using a 3-axis coil system and applying three different low-frequency modulations. The characteristics of the scalar magnetometer significantly affect the achieved vector performance. This paper describes the vectorized scalar magnetometer as well as how the scalar precision, slew rate, and modulation amplitude affect the vector precision. We demonstrate a vector precision of better than 0.5 nT at an integration time of 1 second when applying a modulation amplitude greater than 100 nT.