| Hands, A D P; Ryden, K A; Sandberg, I; Heynderickx, D; Provatas, G; Aminalragia-Giamini, S; Tsigkanos, A; Papadimitriou, C; Rodgers, D; Evans, H: An Update to MOBE-DIC Using Current Monitor Measurements From Galileo. In: IEEE Transactions on Nuclear Science, vol. 67, no. 1, pp. 181-190, 2020, ISSN: 1558-1578. (Type: Journal Article | | | )|
We use electron flux derived from the environment monitoring unit “(EMU)-SURF” current monitor on board a Galileo Global Navigation Satellite System (GNSS) constellation satellite to modify and update the model of outer belt electrons for dielectric internal charging (MOBE-DIC). We describe how this data set, together with data from similar current-measuring instruments on Van Allen Probes, Giove-A, and STRV1d, are used to improve and expand the model. We have extended the spatial range to include the inner belt, exploited EMU data to widen the energy range for the electron spectrum, updated the statistical analysis of flux variation using a data set double the size used for the original model, and established a new and independent latitude function that yields improved agreement in medium earth orbit compared to the original model. The model is entirely characterized by a set of equations and parameters that produce fluxes as a function of magnetic coordinates at three distinct statistical levels.
| Sandberg, I.; Aminalragia-Giamini, S.; Provatas, G.; Hands, A.; Ryden, K.; Heynderickx, D.; Tsigkanos, A.; C.Papadimitriou,; Nagatsuma, T.; Evans, H.; Rodgers, D.: Data Exploitation of New Galileo Environmental Monitoring Units. In: IEEE Transactions on Nuclear Science, vol. 66, no. 7, pp. 1761-1769, 2019, ISSN: 0018-9499. (Type: Journal Article | | | )|
The radiation environment of the Galileo spacecraft is severe and poorly characterized. The Galileo orbit takes the spacecraft through the heart of the outer radiation belt, while the low levels of geomagnetic shielding throughout the orbit expose the spacecraft to intermittent intense fluxes of protons during solar energetic particle events. In the Galileo constellation, two environmental monitoring units (EMUs) are currently flying in two different orbital planes. These units monitor the radiation environment and provide critical information related to hazards for the host spacecraft and its payload. In this paper, we present the results from the analysis of the surface charge collecting plates and the proton telescope sensors. The performed numerical calibration of the EMU sensors and the application of novel unfolding and in-flight cross-calibration techniques allow the calculation of high-quality proton and electron differential fluxes. The creation of a high-quality, long-term EMU electron flux data set, is a step forward toward the improved characterization of medium earth orbit (MEO) environment through the update of the existing or the development of new radiation environment models.
Environment Monitoring Unit
- Mass: 3.5 kg
- Volume: 3 litres
- Power: 8 Watts
- Reliability: 15 year MEO mission
- SURF: 8 stacked charge collection plates, 7 cm diameter,
- 8 Proton Telescopes
- Heavy ion LET sensor
- GSAT0207 (Antoniaana) launched in Nov. 2016
- GSAT0215 (Nicole) launched in Dec. 2017
- Himawari-8 launched in Oct. 2014
|An Update to MOBE-DIC Using Current Monitor Measurements From Galileo. In: IEEE Transactions on Nuclear Science, vol. 67, no. 1, pp. 181-190, 2020, ISSN: 1558-1578.:|
|Data Exploitation of New Galileo Environmental Monitoring Units. In: IEEE Transactions on Nuclear Science, vol. 66, no. 7, pp. 1761-1769, 2019, ISSN: 0018-9499.:|
The Environment Monitoring Unit (EMU) is a radiation monitor designed and built for use in the Galileo orbit. Its design is based on the Giove-A MERLIN and the Cosmic Radiation Environment and Dosimetry (CREDO) instruments. It is manufactured by Thales-Alenia Space, Switzerland.
EMU consists of four separate sensors:
- a set of 8 charge collection plates for measuring internal charging currents under shielding;
- 8 Proton telescopes for measuring energetic proton fluxes;
- an Linear Energy Transfer (LET) heavy ion sensor;
- RadFETS for measuring internal doses inside the instrument.
Two instruments have been flown on the Galileo satellites GSAT207 and GSAT215.