TY - JOUR
T1 - In orbit calibration of the non-orthogonality of the two fluxgate sensors onboard CSES
AU - Tong, Yuqi
AU - Zhou, Bin
AU - Li, Lei
AU - Cheng, Bingjun
AU - Zhang, Yiteng
AU - Magnes, Werner
AU - Lammegger, Roland
AU - Pollinger, Andreas
AU - Yang, Yanyan
AU - Zeren, Zhima
AU - Shen, Xuhui
N1 - Publisher Copyright:
© 2023, The Author(s).
PY - 2023
Y1 - 2023
N2 - With the accumulation of data, it is possible to study the long-term variation of Fluxgate Magnetometers (FGM) of High Precision Magnetometer (HPM) onboard the China Seismo-Electromagnetic Satellite (CSES). The calibration method of HPM depends on an assumption that the linear parameters of FGM, including the gain factors, the offsets, and non-orthogonal angles are stable. However, HPM exhibits some unexpected trends in the scalar residuals when processed according to the assumption. Study on the residual finds out that under changing space thermal conditions, the non-orthogonal angles of FGM change periodically, suggesting that the data calibration method we used before should be modified. A multi-dimensional polynomial model is established for defining the change of non-orthogonal angles of FGM as a function of the sun incidence angles, geographic latitude and sensor temperature. Apply the polynomial model to data from August 2018 to May 2021, the standard deviation of the scalar residuals is reduced to around 0.5 nT and tends to be more random and in line with the normal distribution. Meanwhile, the variation trend in gain factors and offset factors are eliminated. Results show that the model can correctly reflect the period variation of the non-orthogonal angles of FGM with the space thermal conditions. Graphical Abstract: [Figure not available: see fulltext.].
AB - With the accumulation of data, it is possible to study the long-term variation of Fluxgate Magnetometers (FGM) of High Precision Magnetometer (HPM) onboard the China Seismo-Electromagnetic Satellite (CSES). The calibration method of HPM depends on an assumption that the linear parameters of FGM, including the gain factors, the offsets, and non-orthogonal angles are stable. However, HPM exhibits some unexpected trends in the scalar residuals when processed according to the assumption. Study on the residual finds out that under changing space thermal conditions, the non-orthogonal angles of FGM change periodically, suggesting that the data calibration method we used before should be modified. A multi-dimensional polynomial model is established for defining the change of non-orthogonal angles of FGM as a function of the sun incidence angles, geographic latitude and sensor temperature. Apply the polynomial model to data from August 2018 to May 2021, the standard deviation of the scalar residuals is reduced to around 0.5 nT and tends to be more random and in line with the normal distribution. Meanwhile, the variation trend in gain factors and offset factors are eliminated. Results show that the model can correctly reflect the period variation of the non-orthogonal angles of FGM with the space thermal conditions. Graphical Abstract: [Figure not available: see fulltext.].
KW - CSES satellite
KW - Fluxgate magnetometer
KW - High precision magnetometer
KW - Instrument calibration
UR - http://www.scopus.com/inward/record.url?scp=85147882048&partnerID=8YFLogxK
U2 - 10.1186/s40623-023-01766-y
DO - 10.1186/s40623-023-01766-y
M3 - Article
AN - SCOPUS:85147882048
SN - 1343-8832
VL - 75
JO - Earth, Planets and Space
JF - Earth, Planets and Space
IS - 1
M1 - 21
ER -