Browsing by Author "Yen, Nick"

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Constellation challenges and contributions of Taiwan weather monitoring satellites
(2008)
Fong, Chen-Joe
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Yen, Nick
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Chu, Vicky
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Yang, Eddy
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Huang, Cheng-Yung
National Space Organization (NSPO) of Taiwan in the past ten years has successfully launched three different types of satellites. The latest one is FORMOSAT-3/COSMIC, a joint Taiwan-US project, which was successfully launched on April 15, 2006. The FORMOSAT-3 is a constellation of 6 satellites and each satellite is equipped with GPS Occultation Receiver (GOX), Tri-Band Beacon (TBB), and Tiny Ionospheric Photometer (TIP). The constellation is on the way to its final orbit configuration. All satellites remain healthy except spacecraft Right model no. 2 (FM2) with a problem of power shortage and FM3 currently staying at an orbit of 711 km due to a mechanism issue to be solved. The current sounding profiles retrieved from the GPS occultation measurements are over an average of 1800 daily. The sounding profiles have been used to study atmospheric and ionospheric structures and total electron content, and assimilated into numerical atmospheric and space weather predictions models to improve the accuracy of prediction. Taiwan has taken an active role and grown remarkably well in remote sensing researches during the last decade. Taiwan will continue to share her resources with the international community for scientific research and applications. In this paper, we will present an overview of significant contributions of the FORMOSAT-3/COSMIC satellite mission to the global community. We will also describe the constellation challenges and novel operations solutions and the future follow-on mission planning. (1 2).
GPS radio occultation and mission results from FORMOSAT-3/COSMIC spacecraft constellation
(2007)
Fong, Chen-Joe
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Yen, Nick
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Yang, Shan-Kuo
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Chen, Shao-Shing
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Chi, Sien
The FORMOSAT-3/COSMIC spacecraft constellation consisting of six LEO satellites is the world\'s first operational GPS radio occultation mission. The mission is jointly developed by Taiwan\'s National Space Organization (NSPO) and United States\' UCAR in collaboration with NASA\'s Jet Propulsion Laboratory and Naval Research Laboratory. The FORMOSAT-3/COSMIC mission was successfully launched from Vandenberg on April 15, 2006 into the same orbit plane of the designated 516 kin circular parking orbit altitude. All six FORMOSAT-3/COSMIC satellites are maintained in the good state of health and are on their way toward the final constellation of six separate orbit planes with 30-degree separations. Three out of six satellites have reached their final mission orbit of 800 km by the middle of February 2007. The FORMOSAT-3/COSMIC has processed over 2500 good ionospheric sounding profiles and 1800 good atmospheric sounding profiles (similar to 900 mostly above the land mass) per day which has over the number of worldwide radiosondes launched per day. The atmospheric radio soundings data are assimilated into the Numerical Weather Prediction (NWP) models for real-time weather prediction and typhoon/hurricane forecast. This paper describes the mission overview; the space and ground segment architecture; the operations challenges encountered during the constellation deployment phase; and the state-of-the-art achievements and mission results of the FORMOSAT-3/COSMIC that affect the RO data retrievals. The ultimate success of a real-time operation of the FORMOSAT-3/COSMIC mission in the final constellation formation can be anticipated.
Mission Results from FORMOSAT-3/COSMIC Constellation System
(2008-11-01)
Fong, Chen-Joe
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Huang, Cheng-Yung
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Chu, Vicky
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Yen, Nick
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Kuo, Ying-Hwa
The FORMOSAT-3/COSMIC spacecraft constellation consisting of six low-Earth-orbit satellites is the world's first operational Global Positioning System radio occultation mission. Its mission is jointly developed by Taiwan's National Space Organization and the United States's University Corporation for Atmospheric Research in collaboration with NASA's Jet Propulsion Laboratory and the Naval Research Laboratory for the three onboard payloads, which include the Global Positioning System occultation receiver, the triband beacon, and the tiny ionospheric photometer. The FORMOSAT-3/COSMIC mission was launched successfully from Vandenberg Air Force Base on 15 April 2006 into the same orbit plane of the designated 516 km circular parking orbit altitude. All six FORMOSAT-3/COSMIC satellites are maintained in a good state of health except spacecraft flight model 2, which has a power shortage, and flight model 3, currently staying at an orbit of 711 km due to a mechanism problem to be solved, and are on their way toward the final constellation of six separate orbit planes with 30 deg separations as planned. Five out of six satellites have reached their final mission orbit of 800 km as of November 2007. The FORMOSAT-3/COSMIC has processed over 1800 good atmospheric sounding profiles per day on average, which is larger than the number of worldwide radiosondes launched per day (similar to 900, mostly above the land). The atmospheric radio occultation sounding data are assimilated into the numerical weather prediction models for real-time weather prediction and typhoon/hurricane forecast. The global and some major nations' weather prediction centers have shown a significant positive impact and the forecast result will be also adapted to Taiwan's disaster warning and relief system once constellation deployment is completed by the end of 2007. With the invention of the open-loop technique by University Corporation for Atmospheric Research, the quality, accuracy, and lowest penetration altitude of the radio occultation sounding profiles are better than CHAMP data. This paper also describes the mission highlight, the constellation spacecraft system performance summary, the constellation mission operation result, and the mission science results.
Operations challenges from the FORMOSAT-3/COSMIC constellation for global Earth weather monitoring
(2007)
Fong, Chen-Joe
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Yen, Nick
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Chu, Vicky
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Chen, Shao-Shing
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Chi, Sien
The joint Taiwan-U.S. FORMOSAT-3/COSMIC spacecraft constellation, consisting of six LEO satellites, is the world\'s first operational GPS radio occultation mission for global Earth weather forecast, climate monitoring, atmospheric, ionospheric and geodesy researches. The FORMOSAT-3/COSMIC satellites were launched successfully from Vandenberg on April 15, 2006 into the same orbit plane of the designated 516 km circular parking orbit altitude. After the six satellites completed in-orbit checkout activities, the mission was started immediately at the parking orbit for in-orbit checkout, calibration, and experiment of three onboard payloads. Individual spacecraft thrust bums for orbit raising were performed to begin the constellation deployment of the satellites into six separate orbit planes. Two spacecraft have already reached their final mission orbit of 800 km by the end of December 2006. The FORMOSAT-3/COSMIC has processed over 1500 good atmospheric sounding profiles per day, which has exceeded the number of worldwide radiosondes launched (similar to 900 mostly above the land mass) per day and over 2500 good ionospheric sounding profiles per day, respectively. The atmospheric radio soundings data are assimilated into the Numerical Weather Prediction (NWP) models for real-time weather predictions and typhoon/hurricane forecasts. This paper describes the system overview, constellation mission operations, operations challenges, intense operation period campaign early results, and the operations lessons learned from this FORMOSAT-3/COSMIC mission.(1 2).