A radiation tolerant digital fluxgate magnetometer

Fluxgate magnetometers have a long heritage of measuring the magnetic fields aboard space missions to all regions of the solar system. Fluxgate sensors have the stability, mass and resolution required for the space environment. However, future missions demand reductions in the mass and power of the electronics associated with these sensors and electronics designs which can survive the harsh radiation environment of space. Here a new design concept and first results are presented for a fluxgate magnetometer which combines the benefits of digital detection and digital feedback control with the low-noise amplification provided by tuning the sensor. It is also compatible with a mass optimized sensor using common sense/feedback windings. This design has been developed from the analogue design used for the Double Star mission. Moving the field extraction from the analogue to the digital domain reduces the component count and therefore the mass. The use of sigma–delta analogue-to-digital and digital-to-analogue conversion architecture embedded in a field programmable gate array offers the possibility of realizing a complete design able to operate up to a total ionizing dose of radiation of 100 krad without shielding.