Magnetic field data processing methods of the China Seismo-Electromagnetic Satellite

Abstract

The High Precision Magnetometer (HPM) on board the China Seismo‐Electromagnetic Satellite (CSES) allows highly accurate measurement of the geomagnetic field; it includes FGM (Fluxgate Magnetometer) and CDSM (Coupled Dark State Magnetometer) probes. This article introduces the main processing method, algorithm, and processing procedure of the HPM data. First, the FGM and CDSM probes are calibrated according to ground sensor data. Then the FGM linear parameters can be corrected in orbit, by applying the absolute vector magnetic field correction algorithm from CDSM data. At the same time, the magnetic interference of the satellite is eliminated according to ground‐satellite magnetic test results. Finally, according to the characteristics of the magnetic field direction in the low latitude region, the transformation matrix between FGM probe and star sensor is calibrated in orbit to determine the correct direction of the magnetic field. Comparing the magnetic field data of CSES and SWARM satellites in five continuous geomagnetic quiet days, the difference in measurements of the vector magnetic field is about 10 nT, which is within the uncertainty interval of geomagnetic disturbance.

In-orbit results of the Coupled Dark State Magnetometer aboard the China Seismo-Electromagnetic Satellite

“…The CDSM measures the magnetic field strength with the lowest absolute error of the instruments aboard CSES and serves as the reference instrument for the measurements done by the fluxgate sensors. The suitability of the CDSM for the in-flight calibration of the fluxgate magnetometers is discussed in Zhou et al (2019).…”

Ionospheric Pc1 waves during a storm recovery phase observed by the China Seismo-Electromagnetic Satellite

“…The local time of the descending node is 14:00 LT We use magnetic field data from the highprecision magnetometer (HPM) and electric field data from the electric field detector (EFD) on board the CSES. The HPM includes two three-component fluxgate sensors to collect vector magnetic field data with a sampling rate of 60 Hz, and the noise of the sensors is less than 0.02 nT Hz −1/2 at 1 Hz (Zhou et al, 2018(Zhou et al, , 2019. The EFD consists of four spherical sensors, which can realise the three-component electric field detection with a frequency bandwidth of about 3.5 MHz, in which the ultra-low frequency (ULF) band provides a 125 Hz sampled waveform signal (Huang et al, 2018).…”

The Electromagnetic Emissions and Plasma Modulations at Middle Latitudes Related to SURA‐CSES Experiments in 2018

“…There are two operational modes: burst mode in two main seismic belts in the world and China mainland with 1,000‐km surroundings and survey mode for other regions (Huang, Shen, et al, 2018). To monitor the electromagnetic environment and its variations in ionosphere, eight payloads are installed onboard, including a high‐precision magnetometer (HPM) to obtain the three components of the magnetic field below 15 Hz (Cheng, Zhou, et al, 2018; Zhou et al, 2018); a search coil magnetometer (SCM) to observe the magnetic field within the frequency band of 10 to 20 kHz (Cao et al, 2018; Wang et al, 2018); an electric field detector (EFD) to detect the three‐component electric field within the frequency band of direct current (DC) to 3.5 MHz (Chen, Lei, & Ma, 2018; Huang, Lei, et al, 2018); a Langmuir probe (LAP) for electron density and temperature (Yan et al, 2018); a plasma analysis package (PAP) for ion composition, temperature, and drift velocity; a triband beacon (TBB) for electron profiles by emitting three frequency waves to the receivers built on the ground (Chen, Ou, et al, 2018); a Global Navigation Satellite System (GNSS) occultation receiver (GOR) for total electron content (TEC) and electron density profile (Cheng, Lin, et al, 2018); and a high‐energy particle detector (HEPD) for particles at energy band of 100‐keV to 50‐MeV electrons and 2‐ to 200‐MeV protons (Ambrosi et al, 2018; Chu et al, 2018).…”