Characterisation of Magnetic Sensors for Space Applications – an NMI Perspective

Accurate characterisation of magnetic sensors is required across a range of industrial applications. The National Physical Laboratory (NPL), as the UK's National Metrology Institute (NMI), maintains and disseminates measurement standards, with traceability to SI units, that provides characterisation of advanced magnetic sensors from nT-level to several T. Space missions can benefit from the increasing sensitivity and accuracy of magnetic sensors. To calibrate such sensors, a low magnetic noise environment and traceable measurement systems must be established. Both spacecraft design and in-flight operation must rigorously incorporate magnetic cleanliness and compensate for field fluctuations. To reduce measurement uncertainties and dependent sensor error budgets, a greater understanding of the magnetic environment becomes crucial. This presentation will describe the development of traceable measurements systems at NPL that enable the characterisation of these sensors at the nT level for space applications. These systems allow key parameters, such as gain, linearity, offset and noise to be determined, with specific attention given to the measurement of the temperature dependance of these key parameters, and recent developments for the orthogonality of small magnetometers in a fast and cost-efficient way.