NEC Aerospace Systems Ltd.

Tokyo, Japan

NEC Aerospace Systems Ltd.

Tokyo, Japan
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Suenaga T.,Graduate University for Advanced Studies | Suenaga T.,NEC Aerospace Systems Ltd. | Tamura M.,Japan National Astronomical Observatory | Tamura M.,University of Tokyo | And 4 more authors.
Publications of the Astronomical Society of Japan | Year: 2014

We present the results of an H-and K-band multi-object and long-slit spectroscopic survey of substellar mass candidates in the outer regions of the Orion Nebula Cluster. The spectra were obtained using MOIRCS on the 8.2m Subaru telescope and ISLE on the 1.88m telescope of Okayama Astrophysical Observatory. Eight out of twelve spectra show strong water absorption and we confirm that their effective temperatures are ≤3000K (spectral type ≥M6) from a chi-square fit to synthetic spectra. We plot our sources on an HR diagram overlaid with theoretical isochrones of low-mass objects and identify three new young brown dwarf candidates. One of the three new candidates is a cool object near the brown dwarf and planetary mass boundary. Based on our observations and those of previous studies, we determine the stellar (0.08

Miyawaki M.,NEC Aerospace Systems Ltd. | Kimura T.,NEC Corp
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2013

ScanSAR ScanSAR differential interferometric technique is a very powerful tool in order to detect the wide crustal deformation caused by huge earthquakes. © 2013 IEEE.

Fujimura T.,NEC Corp | Imai N.,NEC Corp | Seino Y.,NEC Corp | Kimura T.,NEC Corp | And 2 more authors.
Proceedings of the 2015 IEEE 5th Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2015 | Year: 2015

The new small airborne SAR for disaster monitoring was developed based on the technology of Pi-SAR2 of NICT. The summary of its development was reported in IGARSS 2013 and 2014 [1][2] and will be reported in IGARSS 2015 [3]. This paper reports the evaluation of its disaster monitoring capability using the change detection by the simple amplitude difference method. © 2015 IEEE.

Kyu S.,NEC Aerospace Systems Ltd. | Ishii T.,NEC Aerospace Systems Ltd. | Hagiwara K.,NEC Aerospace Systems Ltd. | Miyawaki M.,NEC Aerospace Systems Ltd. | And 4 more authors.
Conference Proceedings of 2013 Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2013 | Year: 2013

This report introduces a new 3D terrain information reconstructing application software for airborne interferometric SAR. This application enables (1) semi-automation of the reconstruction processing sequences and rapid availability of outcome as a consequence, and (2) composition of DEMs generated from data with different observation angles so that more information can be obtained. An outline of the reconstructing process and some examples of auto-generated DEMs, orthoimage, and perspective view are shown in this paper. The ground height obtained with this application showed quite good agreement with referential DEM and that measured by GPS. © 2013 IEICE.

Sawamura T.,NEC Aerospace Systems Ltd. | Takahashi T.,NEC Corp | Moriguchi T.,NEC Corp | Ohara K.,NEC Engineering Ltd. | And 3 more authors.
Institute of Navigation International Technical Meeting 2012, ITM 2012 | Year: 2012

The Quasi-Zenith Satellite System (QZSS), a Japanese satellite navigation system, broadcasts GPS-interoperable signals and augmentation signals as well as original Japanese signals from an inclined elliptical geosynchronous orbit. Using this system, users around Japan and Oceania can make use of seamless positioning, navigation, and timing services, even in urban canyons and mountainous areas, [1]. The first satellite of the Quasi-Zenith Satellite System, MICHIBIKI, was successfully launched on September 11, 2010, by a Japanese H2A launch vehicle is operating successfully. In-Orbit Checkout was conducted by the government sector, consisting of four ministries, National Institute of Information and Communications Technology, (NICT), National Institute of Advanced Industrial Science and Technology (AIST), Geospatial Information Authority of Japan (GSI), Electronic Navigation Research Institute (ENRI), and JAXA (Japan Aerospace Exploration Agency), and was completed successfully. From the middle of December, 2010, JAXA changed the navigation signals to the standard code. The technical verification and the application demonstration were also conducted and successfully finished in June 2011, [2]. NEC Corporation is responsible for the total system, QZSS, the ground system, and the on-board payload, QZS Navigation Payload (NP). In this paper, the in-orbit performance of the navigation performance of QZSS and L-Band Navigation Payload of QZS-1 are described.

Fujimura T.,NEC Corp | Ono K.,NEC Corp | Nagata H.,NEC Corp | Tozuka H.,NEC Corp | And 5 more authors.
Conference Proceedings of 2013 Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2013 | Year: 2013

The experiment on human and vehicle detection using Pi-SAR2 was carried out on December 12th 2012 in order to confirm the operational performance of Pi-SAR2. Although the sigma zero of human target is approximately -1 dB and is lower than the first assumed value, the human target was detected on Pi-SAR2 image. And the human and vehicle can be split on Pi-SAR2 image. As the result, it was confirmed that Pi-SAR has the potential performance for the detection of human and vehicle. The result of this experiment will be used for the development of a new small airborne SAR which has the same performance as that of Pi-SAR2. © 2013 IEICE.

Miyawaki M.,NEC Aerospace Systems Ltd. | Yamaguchi S.,NEC Aerospace Systems Ltd. | Kimura T.,NEC Corp
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2011

In recent years, huge earthquakes have occurred in many places and those have induced the crustal movements over hundreds of kilometers. In such cases, the entire movement area cannot be observed with differential interferometric SAR processing using Stripmap mode data, because Stripmap mode of ALOS/PALSAR covers only 70km swath. On the other hand, ScanSAR is suitable for extraction of wide-ranging crustal movement caused by huge earthquake due to its wide coverage about 350km swath. Authors tried ScanSAR-ScanSAR differential interferometric processing using a lot of pairs of PALSAR ScanSAR mode data. We processed in two actual huge earthquake cases. One is the 2008 China Wenchuan earthquake (May 12 2008, Mw 7.9) case, and the other is the 2010 Chile earthquake (Feb. 27 2010, Mw 8.8) case. In this paper, the results of these two ScanSAR-ScanSAR differential interferometric SAR processing using PALSAR data are introduced. As a result, it is demonstrated that ScanSAR-ScanSAR differential interferomtry is a very powerful tool to detect the wide-ranging crustal movement caused by a huge earthquake. © 2011 IEEE.

Fujimura T.,NEC Corp | Totsuka H.,NEC Corp | Imai N.,NEC Corp | Matsuo S.,NEC Corp | And 4 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2011

The first bistatic SAR experiment between Japanese spaceborne PALSAR and airborne Pi-SAR-L was successfully performed and gave an excellent image in 2010. This paper mainly reports the result of this bistatic SAR experiment and its data analysis. As the result of the analysis, two conclusions are confirmed. One is the success of the bistatic SAR observation without special functions for them and the other is the advantage of this bistatic SAR observation. © 2011 IEEE.

Maejima H.,Japan Aerospace Exploration Agency | Sasaki S.,Japan Aerospace Exploration Agency | Akagi C.,Asuka Denki Ltd. | Kobayashi H.,NEC Aerospace Systems Ltd. | Ohkami Y.,Keio University
Journal of Spacecraft and Rockets | Year: 2013

KAGUYA was a Japanese large lunar explorer that orbited and observed the moon from 2007 to 2009. During in-orbit operation, unexpected fluctuations and lock-offs of KAGUYA's uplink radio frequency telecommand signal were sometimes observed. To investigate the cause of the fluctuations, archived telemetry data were surveyed, and the telemetry data that showed the fluctuation were extracted. According to fault tree analysis of the telemetry data, multipath interference from the lunar surface and the spacecraft structure was deemed the most probable cause. This finding was verified by geometrical analysis of multipath interference. On the basis of the analysis results, the fluctuationmapfor a lunar polar orbiter was presented for the first time. Thismapwas used to avoid the telecommand operation failure of KAGUYA. This lesson can be generally applied to operations of planet and lunar orbiters.

Hirose C.,Japan Aerospace Exploration Agency | Ishii N.,Japan Aerospace Exploration Agency | Kawakatsu Y.,Japan Aerospace Exploration Agency | Ukai C.,NEC Aerospace Systems Ltd. | Terada H.,NEC Aerospace Systems Ltd.
Advances in the Astronautical Sciences | Year: 2013

The Japanese Venus explorer "Akatsuki (PLANET-C)", which now rotates about the Sun, will approach to Venus again in 2015. For the Venus orbit reinsertion, several trajectory strategies were devised. In this paper, we introduce the difficulties we faced in redesigning the trajectory of Akatsuki after the failure of the first Venus Orbit Insertion (VOI) in 2010 and report some newly devised trajectory control strategies including Gravity Brake Method, which will make the most of the solar perturbations to conduct the Venus orbit insertion for the second time. © 2013 2013 California Institute of Technology.

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