Particle Detector (PD) Experiment of the Korea Space Environment Monitor (KSEM) Aboard Geostationary Satellite GK2A

Estimation of Geometric Factors for the Particle Detecting Instruments of the Geostationary Satellite GK2A at 128.2°E Longitude Based on Observations of the Outer Radiation Belt During Geomagnetically Quiet Periods

“…The estimation of systematic uncertainty was more difficult because of the relatively poor understanding of several effects in the measurements, including the effect of the finite energy bin widths, detector migration, and uncertainties in energy calibrations from the ground experiment, not to mention the effects of the obstructions of the spacecraft. In this study, the systematic uncertainty was estimated as follows: From the ground experiment with the radioisotopes, the energy was determined as a linear function of the measured Analog‐to‐Digital (ADC) binary number, $$E=\mathrm{G}\mathrm{a}\mathrm{i}\mathrm{n}\times \mathrm{A}\mathrm{D}\mathrm{C}+{E}_{\mathrm{o}\mathrm{f}\mathrm{f}\mathrm{s}\mathrm{e}\mathrm{t}}$$, with estimated uncertainties for $$\mathrm{G}\mathrm{a}\mathrm{i}\mathrm{n}$$ and $${E}_{\mathrm{o}\mathrm{f}\mathrm{f}\mathrm{s}\mathrm{e}\mathrm{t}}$$ (Seon et al., 2020). For each of the 39 energy bins, the error propagation formula was applied to the energy at the center of the bin $${E}_{i}$$ to yield the following relation for the uncertainty estimate for the i th energy bin: $$${\sigma }_{{E}_{i}}={\left(\frac{{E}_{i}-{E}_{\mathrm{o}\mathrm{f}\mathrm{f}\mathrm{s}\mathrm{e}\mathrm{t}}}{\mathrm{G}\mathrm{a}\mathrm{i}\mathrm{n}}\right)}^{2}{\sigma }_{\mathrm{G}\mathrm{a}\mathrm{i}\mathrm{n},i}^{2}+{\sigma }_{{E}_{\mathrm{o}\mathrm{f}\mathrm{f}\mathrm{s}\mathrm{e}\mathrm{t}},i}^{2}.$$$ …”

Disappearance of the Polar Cap Ionosphere During Geomagnetic Storm on 11 May 2019

“…Besides these ground‐based observations at JBS, we also utilized the magnetic field (Magnes et al., 2020) and electron flux (Seon et al., 2020) data obtained from the magnetometer and particle detector, respectively, aboard the geostationary satellite Geo‐KOMPSAT‐2A (GK‐2A, geographic longitude: 128.2°E) at geosynchronous orbit to monitor substorm activities. The GK‐2A orbit is located ∼2.5 hr west of JBS.…”

Maximum-variance gradiometer technique for removal of spacecraft-generated disturbances from magnetic field data

“…This holds either when the variance of the disturbance is much larger than the variance of the ambient field or when the variance of the ambient field does not have a preferred direction. In this case, the direction of the disturbance at both sensors can be estimated through variance analysis (Sonnerup and Scheible, 1998;Song and Russell, 1999) of the 3D time series from each sensor. The principal components at each sensor are then the magnetic field components along the maximumvariance directions.…”

“…The proposed method is applied to the Service Oriented Spacecraft Magnetometer (SOSMAG) instrument (Auster et al, 2016;Magnes et al, 2020), which, together with the Particle Detector experiment (Seon et al, 2020), is part of the Korea Space wEather Monitor (KSEM) (Oh et al, 2018) on board the GeoKompsat-2A (GK2A) geostationary spacecraft. SOSMAG consists of four three-axial magnetic field sensors, two of them mounted on a short boom extended from the spacecraft and the other two placed near strong magnetic disturbance sources within the spacecraft.…”