|Paper title||Self-calibrated absolute vector data produced by the ASM absolute magnetometers on board the Swarm satellites: results, availability and prospect|
|Form of presentation||Poster|
Satellites of the ESA Swarm mission carry Absolute Scalar Magnetometers (ASM) that nominally provide 1 Hz scalar data of the mission and allow the calibration of the relative vector data independently provided by the VFM fluxgate magnetometers also on board. Both the 1 Hz scalar data and the VFM calibrated vector data are being distributed as the nominal L1b magnetic data of the mission. ASM instruments, however, also provide independent 1 Hz experimental self-calibrated ASM-V vector data. More than seven years of such data have been produced on both the Alpha and Bravo Swarm satellites since the launch of the mission in November 2013. As we will illustrate, having recently undergone a full recalibration, these data have now been substantially improved, correcting for previously identified systematic issues. They allow the construction of very high quality global geomagnetic field models that compare extremely well with models built using nominal L1b data (to within less than 1 nT RMS at Earth’s surface, 0.5 nT at satellite altitude). This demonstrates the ability of the ASM instruments to operate as a stand-alone instrument for advanced geomagnetic investigations. Having been fully validated, these ASM-V experimental data are now already being distributed to the community upon request (see Vigneron et al., EPS, 2021, https://doi.org/10.1186/s40623-021-01529-7 and https://swarm.ipgp.fr/).
Both Swarm Alpha and Bravo still having each a spare redundant (cold-redundancy) ASM on board, and the currently operating ASM on both satellites being in good shape with no sign of ageing, ASM instruments are precious assets for allowing many more years of both nominal 1 Hz scalar data and experimental ASM-V vector data to be acquired by Swarm Alpha and Bravo in the future, offering the possibility to go on monitoring the field for many more years, even in the event the VFM instruments should face issues. Furthermore the now demonstrated performance of the ASM instrument running in vector mode fully validates its operating mode in space, on which is also based a new miniaturized version of the instrument, known as the Miniaturized Absolute Magnetometer, which can operate on nanosatellites and is currently planned to be flown as part of the payload on the NanoMagSat constellation proposed as a Scout ESA NewSpace Science mission.