Cross-calibration on the electromagnetic field detection payloads of the China Seismo-Electromagnetic Satellite

The China Seismo-Electromagnetic Satellite (CSES) deploys three payloads to detect the electromagnetic environment in the ionosphere. The tri-axial fluxgate magnetometers (FGM), as part of the high precision magnetometer (HPM), measures the Earth magnetic vector field in a frequency range from direct current (DC) to 15 Hz. The tri-axial search coil magnetometer (SCM) detects the alternating current (AC) related magnetic field in a frequency range from several Hz to 20 kHz, and the electric field detector (EFD) measures the spatial electric field in a broad frequency band from DC to 3.5 MHz. This work mainly cross-calibrates the consistency of these three payloads in their overlapped detection frequency range and firstly evaluates CSES’s timing system and the sampling time differences between EFD and SCM. A sampling time synchronization method for EFD and SCM waveform data is put forward. The consistency between FGM and SCM in the ultra-low-frequency (ULF) range is validated by using the magnetic torque (MT) signal as a reference. A natural quasiperiodic electromagnetic wave event verifies SCM and EFD’s consistency in extremely low-frequency and very low-frequency (ELF/VLF) bands. This cross-calibration work is helpful to upgrade the data quality of CSES and brings valuable insights to similar electromagnetic detection solutions by low earth orbit satellites.