Energetic electron detection packages on board Chinese navigation satellites in MEO

Energetic electron measurements and spacecraft charging are of great significance for theoretical research in space physics and space weather applications.In this paper,the energetic electron detection package(EEDP)deployed on three Chinese navigation satellites in medium Earth orbit(MEO)is reviewed.The instrument was developed by the space science payload team led by Peking University.The EEDP includes a pinhole medium-energy electron spectrometer(MES),a high-energy electron detector(HED)based onΔE-E telescope technology,and a deep dielectric charging monitor(DDCM).The MES measures the energy spectra of 50−600 keV electrons from nine directions with a 180°×30°field of view(FOV).The HED measures the energy spectrum of 0.5−3.0 MeV electrons from one direction with a 30°cone-angle FOV.The ground test and calibration results indicate that these three sensors exhibit excellent performance.Preliminary observations show that the electron spectra measured by the MES and HED are in good agreement with the results from the magnetic electron-ion spectrometer(MagEIS)of the Van Allen Probes spacecraft,with an average relative deviation of 27.3%for the energy spectra.The charging currents and voltages measured by the DDCM during storms are consistent with the highenergy electron observations of the HED,demonstrating the effectiveness of the DDCM.The observations of the EEDP on board the three MEO satellites can provide important support for theoretical research on the radiation belts and the applications related to space weather.