Research progress on in-flight calibration of the magnetometer in deep space exploration

Wang Guoqiang

doi:10.19975/j.dqyxx.2023-052

Abstract：Magnetic field measurements play a crucial role in deep space exploration,contributing signific-antly to our understanding of planetary habitability and the space plasma environment.Among the various instru-ments employed in space exploration missions,the fluxgate magnetometer stands out as a widely used tool.However,its zero offset undergoes gradual changes,necessitating regular in-flight calibration.This article compre-hensively reviews in-flight calibration methods for spaceborne magnetometers in deep space exploration,lever-aging physical phenomena inherent to the space environment.The methods for calculating the zero offset can be di-vided into two categories.The first group employs formulas,including the Belcher method,Hedgecock method,Davis-Smith method,and both one-dimensional and three-dimensional mirror mode methods.Notably,the Davis-Smith method emerges as the optimal choice among these approaches.The second group employs probability-based solutions,constituting the in-flight calibration technology of the new generation,which encompasses six al-gorithms.This innovative technology utilizes phenomena such as Alfvén waves,magnetic mirror structures,and current sheets for in-flight calibration.Moreover,this technology can leverage interplanetary magnetic field data,specifically requiring a sufficient data amount(e.g.,4 hours)to calculate the zero offset.Compared to the Davis-Smith method,the in-flight calibration technology of the new generation demonstrates good compatibility,allow-ing for the simultaneous use of different physical phenomena,and scalability.This technology extends its applicabi-lity beyond solar wind,enabling in-flight calibration in the Martian magnetosheath.Currently,this technology has successfully provided calibration services for the magnetic field data of the Tianwen-1 orbiter.