A Hybrid Fluxgate and Search Coil Magnetometer Concept Using a Racetrack Core

A proof-of-concept hybrid magnetometer is presented which simultaneously operates as both a fluxgate and a search coil allowing it to sense the magnetic field from DC to two kHz using a single sensor. Historically, such measurements would normally require two dedicated instruments and each would typically require deployment on its own dedicated boom as the instruments mutually interfere. A racetrack fluxgate core combined with a long solenoidal sense winding is shown to be moderately effective as a search coil magnetometer and the search coil effect can be captured without introducing significant hardware complexity beyond what is already present in a typical fluxgate instrument. Several methods of optimizing the search coil action of the hybrid instrument are compared with the best providing sensitivity and noise performance between comparably sized traditional air core and solid core search coil instruments. This hybrid sensor topology should miniaturize to platforms such a CubeSats where multiple boom-mounted instruments are generally impractical so a single hybrid instrument providing modest, but scientifically useful, sensitivity from DC to kHz frequencies would be beneficial.