Japan Geoscience Union Meeting 2015

Presentation information

International Session (Poster)

Symbol P (Space and Planetary Sciences) » P-PS Planetary Sciences

[P-PS01] Outer Solar System Exploration Today, and Tomorrow

Tue. May 26, 2015 6:15 PM - 7:30 PM Convention Hall (2F)

Convener:*Jun Kimura(Earth-Life Science Institute, Tokyo Institute of Technology), Masaki Fujimoto(Institite of Space and Astronautical Science, Japan Aerospace Exploration Agency), Yasumasa Kasaba(Dep. Geophysics Graduate School of Science Tohoku University), Sho Sasaki(Department of Earth and Space Sciences, School of Science, Osaka University), Takayuki Tanigawa(School of Medicine, University of Occupational and Environmental Health), Yasuhito Sekine(Department of Complexity Science and Enginerring, Graduate School of Frontier Science, University of Tokyo), kunio Sayanagi(Hampton University), Steven Vance(Jet Propulsion Laboratory, Caltech)

6:15 PM - 7:30 PM

[PPS01-P03] JUICE-GALA : Concept of Focal Plane Assembly and Analog Electronics Module

*Masanori KOBAYASHI1, Ko ISHIBASHI1, Keigo ENYA2, Shin UTSUNOMIYA2, Noriyuki NAMIKI3, Hirotomo NODA3, Shoko OSHIGAMI3, Shingo KASHIMA3, Hiroshi ARAKI3, Jun KIMURA4, Shingo KOBAYASHI5, Masayuki FUJII6, Hauke Hussmann7, Kay Lingenauber7, Jurgen Oberst7 (1.Planetary Exploration Research Center, Chiba Institute of Technology, 2.ISAS, JAXA, 3.RISE Project, National Astronomical Observatory of Japan, 4.Earth-Life Science Institute, Tokyo Institute of Technology, 5.National Institute of Radiological Sciences, 6.FAM Science Co., Ltd., 7.Deutsches Zentrum fur Luft- und Raumfahrt)

Keywords:JUICE, GALA, Laser altimeter, APD, Ganymede, analogue signal processing circuit

Ganymede Laser Altimeter (GALA) is scheduled on board JUICE mission by ESA to be launched in 2022. GALA will be developed and manufactured jointly by teams of Germany, Japan, Switzerland, and Spain. Japanese team is responsible for a receiver unit out of GALA instrument; a receiver telescope, a backend optics (BEO), a focal plane assembly (FPA) accommodating an APD sensor module and an analog electronic module (AEM).
Return laser pulse from the target body is collected by the receiver telescope and is fed into the following BEO. The BEO focuses the return light on the surface of an APD sensor contained in an APD module. For APD as optical sensor, we adopted a product of Excelitas Technologies Corporation that has a lot of experiences in space laser altimeter. The APD sensor is mounted on a hybrid IC of the APD module including a trans-impedance amplifier (TIA) for signal readout in a wide band width as 120MHz, a thermos-sensor for measurement of the APD sensor temperature and a thermoelectric (TE) cooler for control of the APD sensor temperature to stabilize the temperature as 25 deg-C or so. The APD sensor has an enhanced quantum efficiency of up to 40% at 1060 nm. APD typically has a large temperature dependency of gain. The APD module is equipped with TE cooler and the TE cooler is capable to control the temperature of APD precisely. Two redundant optical fibers are attached to the FPA so that a part of transmitted laser pulse generated in Laser head Module (LHM) is introduced to the APD sensor.
The TIA in the APD module outputs voltage signals corresponding to the input light pulses. The voltage signals are fed into the AEM. The transmitted pulses introduced from LHM are attained not to overshoot by a programmable amplifier in the AEM because the following part of analogue signal processing circuit in AEM is to be tuned for signals returned from the target body which are much smaller than the introduced laser pulses. Signal waveform from the introduced laser pulse to the received return pulse is converted to digital data by analogue-to-digital conversion (ADC) circuit and digitized waveform are transmitted to a range finder module (RFM). In RFM, the digital waveform with the transmitted pulse and the received pulse are filtered to optimize signal-to-noise ratio by "matched filter" and the timings of both pulse are detected for ranging and also the width and height of the received pulse can be identified more precisely.
In our poster presentation, the current development status of the optical sensor and analogue module of GALA will be reported.