Earth Planets Space, Vol. 60 (No. 4), pp. 353-363, 2008
Hisayoshi Shimizu1, Futoshi Takahashi2, Naoki Horii2, Ayako Matsuoka3, Masaki Matsushima2, Hidetoshi Shibuya4, and Hideo Tsunakawa2
1Earthquake Research Institute, University of Tokyo, Tokyo, Japan
2Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, Japan
3Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Kanagawa, Japan
4Department of Earth Sciences, Kumamoto University, Kumamoto, Japan
(Received March 26, 2007; Revised August 14, 2007; Accepted October 31, 2007; Online published April 9, 2008)
Ground calibration experiments of the SELENE high sensitivity fluxgate Lunar Magnetometer (LMAG) have been performed in order to determine the alignment, sensitivity, and offset of the sensors (MGF-S). It is checked out that the sensors are orthogonal to each other within 0.4 degrees, and the linearity of the ambient magnetic field and the output from the sensors are confirmed. Also, the temperature dependences of the offset and sensitivity are examined but no clear signatures of temperature dependencies can be seen. SELENE has an in-flight calibration system in order to determine the direction of the magnetometer routinely. The magnetic fields generated by the sensor alignment monitor coil (SAM-C) system are used for the in-flight calibration. The magnetic field distributions generated by SAM-C are determined and the accuracy of determination of the magnetometer position and direction is estimated. Multiple measurements will allow us to determine the direction of MGF-S with about 0.1-degree accuracy. Appropriate corrections from the results of the ground and in-flight calibrations will allow us to recover the magnetic field near the moon with accuracy about 0.1 nT.
Key words: SELENE project, magnetometer, ground calibration, in-flight calibration.