Approaching the First Global Radio Occultation Operational Mission Using Constellation LEO Satellites

Transcription

1 Approaching the First Global Radio Occultation Operational Using Constellation LEO Satellites Nick L. Yen, Chen-Joe Fong, G.-S. Chang National Space Organization (NSPO) F8, No. 9, Prosperity 1 st Rd. Hsinchu, Taiwan 30078, R.O.C x[1053], [9202], [8102] [longine], [cjfong], Abstract The FORMOSAT-3 mission, also known as COSMIC (Constellation Observing for Meteorology, Ionosphere, and Climate) consisting of six Low Earth Orbit (LEO) satellites is an experimental Science for demonstrating the usefulness of Radio Occultation (RO) in operational numerical weather prediction, climate monitoring, and space weather forecasting. By measuring the phase delay of radio waves from GPS satellites as they are occulted by the Earth s atmosphere, accurate and precise vertical profiles of the bending angles of radio wave trajectories are obtained in the ionosphere, stratosphere and troposphere. Consequently, the profiles of electron density in the ionosphere, temperature in the stratosphere, and temperature and water vapor in the troposphere can be derived from the retrieved RO data. The launch of the FORMOSAT-3 mission marked the beginning of a new era of Global Positioning (GPS) atmospheric remote sensing by using Radio Occultation (RO) technique in constellation formation. The retrieved RO weather data (initially ~ 2,400+ per day soon after launch in April 2006 and degraded to currently ~ 1,200+ per day on average after nearly 6 years in orbit) by the six satellites were assimilated into the Numerical Weather Prediction (NWP) model by many major weather forecast centers and research institutes for real-time weather predictions and cyclone/typhoon/hurricane forecasts. The GPS-RO data has been demonstrated to be valuable to the global users of climate, meteorology, and space weather. The global users include many major real-time forecasting centers, and the international research communities. The RO data from FORMOSAT-3 / COSMIC has proven to increase the accuracy of the predictions of hurricane/typhoon/cyclone behavior, significantly improve long-range weather forecasts, and monitor climate change with unprecedented accuracy. The success of the FORMOSAT-3/COSMIC mission has initiated a new age for operational GPS RO soundings. However, FORMOSAT-3 / COSMIC has reached the end of its 5 years design life in 2011, and the critical real-time satellite observing capability has begun to degrade. One out of the six FORMOSAT-3/COSMIC satellites has exhibited inoperative, the remaining five satellites are expected to become inoperative in the near future. The World Meteorological Organization (WMO) has recommended continuing RO observations operationally and the scientific community urges the continuation of the current mission and the planning for a future follow-on Operational. The WMO also calls for the international collaboration to form a global constellation for RO soundings with high number of small satellites in support of the Societal Benefit Areas (SBA) of the Global Earth Observation of s (GEOSS) including weather and climate. As a result and in an effort to reduce the foreseeable global GPS-RO data gap, Taiwan and the U.S. intend to collaborate to jointly develop, launch and operate a high-reliability next generation follow-on satellite mission to FORMOSAT-3/COSMIC, referred to as FORMOSAT-7/COSMIC-2 mission through their agencies the National Space Organization (NSPO) and the National Oceanic and Atmospheric Administration (NOAA), respectively. This report will describe the FORMOSAT- 3/COSMIC mission achievements and the FORMOSAT- 7/COSMIC-2 mission objectives, overview, constellation configuration baseline, as well as the technology that will be used to approach the first global operational Radio Occultation mission. TABLE OF CONTENTS 1. INTRODUCTION FORMOSAT-3 MISSION ACHIEVEMENTS FORMOSAT-7 MISSION OVERVIEW FORMOSAT-7 CURRENT STATUS CONCLUSION... 7 ACKNOWLEDGEMENTS... 7 REFERENCES... 7 BIOGRAPHY INTRODUCTION NSPO along with the U.S. partners, i.e. NSF, UCAR, NASA, JPL, USAF and NOAA, have been on the forefront of radio occultation measurements in launching the FORMOSAT-3 / COSMIC mission in The FORMOSAT-3 constellation consisting of six satellites in Low Earth Orbit (LEO) at 72-degree inclination was launched in April The launch of the FORMOSAT-3 mission marked the beginning of a new era of Global Positioning (GPS) atmospheric remote sensing by using Radio Occultation (RO) technique in constellation formation, as illustrated in Figure 1. [1-4] The GPS RO data 1

2 that has been regarded as the Most Accurate and Stable Thermometer in Space have being widely used by the worldwide major weather centers for the weather forecast and climate monitoring and by the global scientific community for the atmospheric meteorology, ionosphere, and geodesy researches. Especially, it provides at least 60% of the assimilated observations for worldwide Numerical Weather Prediction centers for the last 6+ years. Although the FORMOSAT-3 / COSMIC constellation is now several years beyond its initial life time, NSPO is still providing significant resources to allow the extraction and provision of occultation measurements in Near-Real-Time to continuously serve the global users. Figure 1 Illustration of FORMOSAT-3 GNSS Radio Occultation Technique (Courtesy of UCAR) The World Meteorological Organization (WMO) has recommended continuing RO observations operationally and the scientific community urges the continuation of the current mission and the planning for a future follow-on Operational. The WMO also calls for the international collaboration to form a global constellation for RO soundings with high number of small satellites in support of the Societal Benefit Areas (SBA) of the Global Earth Observation of s (GEOSS) including weather and climate. [5] As a result and in an effort to reduce the global GPS-RO data gap, Taiwan and the U.S. have proceeded to the implementation of a new collaboration program to jointly develop, launch and operate a follow-on satellite mission to FORMOSAT-3, referred to as FORMOSAT-7/COSMIC-2 mission, through their agencies the National Space Organization (NSPO) and the National Oceanic and Atmospheric Administration (NOAA), respectively. This paper will describe the FORMOSAT-3 mission achievements and the FORMOSAT-7 mission objectives, overview, baseline, as well as the technology that will be used to meet those objectives. 2. FORMOSAT-3 MISSION ACHIEVEMENTS RO Sounding Data The global GPS-RO data from FORMOSAT-3 has proven to increase the accuracy of the predictions of hurricane / typhoon / cyclone behavior, significantly improve longrange weather forecasts, and monitor climate change with unprecedented accuracy. Several worldwide weather operation centers have ingested FORMOSAT-3 data into their operational weather forecast models and forecasting abilities have been significantly improved. These include the NOAA National Centers for Environmental Prediction (NCEP), the European Centre for Medium-Range Weather Forecasts (ECMWF), the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), the Central Weather Bureau (CWB) of Taiwan, the United Kingdom Meteorological Office, the Japan Meteorological Agency (JMA), the United States Air Force Weather Agency (AFWA), the Canadian Meteorological Centre (Canada Met), Météo-France, the Bureau of Meteorology of Australia and others. The FORMOSAT-3 constellation has successfully improved global weather analyses and predictions, the accuracy of weather prediction models, and the understanding of tropical, mid-latitude and polar weather systems and their interactions. Due to the success of FORMOSAT-3, this mission became the world s first operational GPS-RO mission for global Earth weather forecasting; climate monitoring; and atmospheric, ionospheric, and geodetic research. [1-4] Assimilation Results ECMWF and NOAA/NCEP started assimilating observations from the FORMOSAT-3 mission into its global data assimilation system in December 2006 and May 2007, respectively. Results demonstrated that the use of GPS RO observation provides information on the state of the atmosphere not available from the other satellite instruments. From a typical example as shown in Figure 2, it is observed that GPS-RO provided 8 hours improvement in forecast skill at Forecast Day 4 and more than 5 hours improvement in forecast skill at Forecast Day 7. [6] There are particularly significant improvements over the oceans and in Southern This paper will describe the general achievement of the FORMOSAT-3/COSMIC mission and the implementation of its following-on FORMOSAT-7/COSMIC-2 mission. 2

3 Hemisphere. Anomaly Correction Southern Hemisphere 500 mb Height WITHOUT COSMIC WITH COSMIC potential GPS-RO data gap until the follow-on mission can be commissioned in Data Point Forecast Day /15/06 10/15/06 4/15/07 10/15/07 4/15/08 10/15/08 4/15/09 10/15/09 4/15/10 10/15/10 4/15/11 10/15/11 4/15/12 10/15/12 a) Figure 2 Prediction accuracy improvement on global prediction model by assimilating FORMOSAT-3 RO data into NOAA/NCEP s global data assimilation system (Courtesy of L. Cucurull of NOAA) This is due to the unique characteristics of the GPS RO measurements: unbiased observations, high accuracy, high vertical resolution, and equal accuracy over land and over ocean, and all-weather capability. The benefits of FORMOSAT-3 RO data are significant in terms of weather forecast skill. The assimilation of GPS RO observations improved anomaly correlation scores for the geopotential heights and reduced model biases and root-mean-squared errors of temperature and wind fields. These benefits are expected to increase with a larger constellation of LEO satellites carrying the GPS RO receivers. FORMOSAT-3 as Achieved and its Outlook for 2012 and Beyond The mission currently serves near 2,000 registered users from 64 countries. On average, FORMOSAT-3 provides 1,500 ~ 2,000 GPS-RO soundings per day at the initial mission years (2006 ~2009), uniformly distributed around the globe. Approximately 90% of the data are available within 3 hours of observations to support operational numerical weather prediction. FORMOSAT-3 GPS-RO soundings has been declined to ~1,000 data volume per day in 2010 till early The FORMOSAT-3 mission has retrieved over 3.12 million soundings as-of September 2012 for atmospheric and ionospheric events, respectively, since the satellites launch, as shown in Figure 3. Despite that the FORMOSAT-3 satellites have reached its five-year design life in 2011, and the critical real-time satellite observing capabilities have been degrading as anticipated and the entire fleet may become inoperative in the next few years. [4] NSPO and the U.S. partners will continue to operation the FORMOSAT-3 constellation to provide the global data to the extent possible to shorten the Data Point /15/06 10/15/06 4/15/07 10/15/07 4/15/08 10/15/08 4/15/09 10/15/09 4/15/10 10/15/10 4/15/11 10/15/11 4/15/12 10/15/12 b) Figure 2 Statistics of the number of daily occultation events as-of September 2012 since launch: a) atmospheric profiles and b) ionospheric profiles Objectives 3. FORMOSAT-7 MISSION OVERVIEW The mission objectives of the FORMOSAT-7/COSMIC-2, referring as FORMOSAT-7 for simplicity in the remaining descriptions of this article, are similar to that of the FORMOSAT-3: to reliably provide data for Numerical Weather Prediction (NWP); to perform space weather monitoring; and to trend climate change. Baseline The FORMOSAT-7 mission baseline is illustrated in Table 1. The FORMOSAT-7 will deliver more useful RO data to the global data users by implementing more LEO satellites and intercepting Global Navigation Satellite (GNSS) signals including U.S. s GPS, Europe s Galileo, and Russian s Global Navigation Satellite (GLONASS) signals with an advanced satellite-based RO receiver to retrieve the temperature, pressure, moisture, and electron density gradients in the atmosphere and ionosphere. [7-11] The FORMOSAT-7 constellation is expected to produce more than 8,000 soundings per day, compared to the approximate 1,500~2,000 soundings per day produced 3

4 by the FORMOSAT-3 that only can track only the U.S. s GPS navigation system s signals. [7] Constellation Orbit Payload Science Payloads Launcher First Launch 6 satellites Low-inclination angle orbit Inclination 24 ~ 28.5 deg [TBR] Parking altitude 720 km, altitude 520~550 km Circular orbit TriG (GNSS RO payload) Radio Beacon scintillation instrument Velocity, Ion Density and Irregularities (VIDI) instrument EELV-like new LV (rideshare) Second Launch 6 satellites with one NSPO built satellite [TBR] High-inclination angle orbit Inclination 72 deg (+/- 1deg), Parking altitude 520 km, altitude 720~ 750 km Circular orbit TriG (GNSS RO payload) Taiwan-furnished payload Minotaur IV series or Falcon-9 Launch schedule Maximum Daily Average Data Latency Communication Architecture Ground Station 45 minutes S-FTP Multicast via VPN Internet There shall be sufficient ground stations to meet the data latency requirement Function FORMOSAT-7 Design FORMOSAT-3 Design Spacecraft Bus Reliability Table 2: FORMOSAT-7 Enhanced Satellite Design meteorology, ionosphere, and climate. The planned science payloads of the first six satellites are the VIDI (Velocity, Ion Density and Irregularities Instrument) Instruments and RF Beacon instrument for space weather application. The science payloads of the second six satellites are under evaluations and have not determined. [7-11] Architecture >0.66 for 5 Years >0.68 for 2 years Weight 150~200 kg 61 kg (w/ Propellant) Attitude Control Performance Data Storage Avionics Architecture Electrical Power Payload Interface 3-axis linear control Roll/Yaw/Pitch:+/-1o (3σ) Attitude Knowledge: better than 0.05o (3σ), all axis GPS Bus Receiver x 1 Bus: > 256 Mbits Science: >2Gbit Centralized Architecture Radiation - Hardness 10 % Power Margin Lithium Ion Battery Voltage Based Algorithm PL: TriG Science PL: VIDI & RF Beacon 3-axis nonlinear control Roll/Yaw: +/-5o (1 σ) Pitch: +/- 2o (1 σ) GPS Bus Receiver PL x Mbyte Distributed Architecture (Multiple Avionics Boxes) 10 % Power Margin Ni-H2 Battery dmdc Charging Algorithm Primary PL: GOX Secondary PL: TIP, TBB FORMOSAT-7 is a much improved constellation system consisting of a new constellation of 12 satellites for transitioning from FORMOSAT-3, a Research, to an Operational. The FORMOSAT-7 satellite system will include the required robustness design and equip with high-reliability components to meet the operational objectives. The FORMOSAT-7 mission architecture is shown in Figure 4. Primary Data Processing Centers US-DPC (UCAR) and Taiwan-DPC (TACC) GALILEO or GLONASS-FDMA GPS Table 1: FORMOSAT-7/COSMIC-2 Baseline High-inc Space Segment The FORMOSAT-7 spacecraft design and mission payload instrument are improved from the current FORMOSAT-3 system with the required operational robustness. The mission payload is a TriG GNSS-RO receiver and will collect more RO data profiles by adding GALILEO and GLONASS tracking capability, which will produce a significantly higher spatial and temporal density of profiles over tracking GPS signals alone. These will be much more useful for weather prediction models and for severe weather forecasting (including typhoon, cyclone and hurricane forecasting), as well as for related research in the fields of Spare S/C FORMOSAT-7/ COSMIC-2 Minotaur IV or Falcon 9 TT&C stations (overseas) TT&C stations (Taiwan) Satellite Operations and Control Center Users US DPC Low-inc Fiducial Network Taiwan DPC Researchers Figure 4 FORMOSAT-7 Architecture 4

5 The constellation is comprised of 6 satellites at 72-degree inclination with altitude of 720~750 km, and 6 other satellites at 24-degree inclination with altitude of 520~550 km, which will enhance observations in the equatorial region over what is currently being collected with FORMOSAT-3. In addition, NSPO intends to develop one self-reliant satellite of the same satellite class. This satellite will be piggy-back launched together with the second set of 6-satellites when feasible and will be placed in a circular orbit with altitude of 600 km. Figure 5 shows the constellation configuration of FORMOSAT-7. The constellation configuration was optimally selected for the uniform global coverage and the desired greater equatorial spatial coverage. [7-11] The current plan is to use 2 launch vehicles with 6 satellites on each vehicle either EELV-like new LV or in the class of Minotaur-IV plus, or Falcon-9. They will be launched in cluster and then individually positioned into their final orbits. It is planned that there will have at least 2 data downlinks per orbit, which will reduce the data latency considerably. The expected average data latency of radio occultation profiles for the FORMOSAT-7 mission is 45 minutes. FORMOSAT-7 Figure 5 FORMOSAT-7 Constellation Configuration Ground Communication Network Figure 6 shows the FORMOSAT-7 Ground Communication Network (GCN) to achieve the expected 45 minutes data latency. (a) 5 (b) Figure 6 Candidate Ground Stations for Satellites at a) High-Inclination-Angle Orbitand b) Low-Inclination- Angle For satellites at high-inclination-angle orbit, there will be 2 remote receiving stations located in the northern hemisphere locations and 2 ground receiving stations located in the southern hemisphere locations. The FORMOSAT-7 mission is being developed in order to optimize and allow use of the current FORMOSAT-3 Network as much as possible. For satellites at low-inclination-angle orbit, there will be 2 ground reception fences of 3 receiving stations on appropriately opposite sides of the earth. The geo-location of the ground receiving stations will enable the downlink of the operational mission data twice per orbit for every lowinclination angle satellite. The candidate sites are the stations located in Taiwan, Singapore, Darwin, Florida, Kourou, and Cuiaba. [7] The high-level ground station requirements are outlined in Table 3. Parameter Value Antenna Size 3.2 meters (provides ~6 db margin at 10 Deg elevation) Minimum Receive G/T 13dB/K Downlink band S-band Data Type CCSDS-2 Downlink Data Rate 2 Mbps, 32 Kbps Downlink Volume <60 Mbytes/Orbit Communication >1MB/s sftp Multicast Out Uplink Band S-Band Uplink Data Rate 32 Kbps Table 3: High-Level Ground Station Specifications Data Processing As with FORMOSAT-3, the data collected by FORMOSAT-7 will be downlinked to the tracking station, then transferred to the U.S. Data Processing Center (DPC) as well as to the Taiwan Data Processing Center (TDPC). The processed products will then be provided to NOAA Global Transmission (GTS) for distribution to the worldwide weather prediction centers. The NSPO Satellite Operations Control Center (SOCC) will provide command and control of the FORMOSAT-7 satellite constellation.

6 Data Distribution Comparison Figure 7 illustrates the comparison of sounding distribution over a 3-hour period between FORMOSAT-3 and FORMOSAT-7. The denser GNSS-RO distribution will enhance the societal and scientific impacts for weather/climate research and forecasting worldwide, with particularly enhanced benefits in the equatorial region. [7] FORMOSAT-3 Occultation 3 Hrs Coverage observing capability has begun to degrade due to satellite un-recoverable anomalies or mortality (one out of six satellites). In February 2008, NOAA s Under Secretary of Commerce for Oceans and Atmosphere stated in his FY10 FY14 Decision Memorandum that the NOAA was to develop a follow-on plan for the COSMIC. In parallel, in June 2011, NSPO submitted FORMOSAT-7 Execution Plan in Taiwan that is approved under the second phase of the 15-year National Space Technology Long Term Development in Taiwan by the National Science Council (NSC). As a result, NOAA and NSPO implemented the Joint Office (JPMO) to carry out the joint mission and intend to provide GPS-RO data continuity and improve sensing capability with the next-generation, FORMOSAT-7/COSMIC-2. The joint mission is implemented based on the work share collaboration. Each party will contribute to the funding in proportion to their respective participation in such activities. Major Reviews and Documents (a) FORMOSAT-7 Occultation 3 Hrs Coverage The Joint FORMOSAT-7 Office had held the Feasibility Design Review (FDR) in May 2010, the Definition Review (MDR) in August 2010, the Payload Preliminary Design Review in January 2011, the s Requirements Review (SRR) in April 2011, the s Design Review (SDR) in June of 2011, and a Technical Interchange Meeting in October of Four major documents, which include the Joint Level One Performance Requirements Document (JL1PRD), the Joint Control Plan (JMCP), the Joint Requirements Document (JMRD), and the Joint s Requirements Document (JSRD) are completed and used as the basis of the joint program execution. Collaborative Framework Figure 8 depicts the joint mission collaborative framework. [8] (b) Figure 7 Sounding Distribution Comparison for a) FORMOSAT-3 Occultation 3 Hours Coverage vs. b) FORMOSAT-7 Occultation 3 Hours Coverage Key Design Requirements Table 2 shows the satellite design requirements comparison for FORMOSAT-7 and FORMOSAT-3. The benefit and improvement for the FORMOSAT-7 spacecraft will improve payload performance, better altitude control performance, simplified operation, increased data storage, and modular design for accommodation of additional compatible science payload. 4. FORMOSAT-7 CURRENT STATUS Joint Office (JPMO) The FORMOSAT-3 mission has exceeded the end of its design life in 2011, and the critical real-time satellite WBS 1.0 Advisory & Supervision Joint International Cooperation NSPO NOAA WBS 2.0 Analysis & Interface Verification Operations WBS 3.0 Assurance NSPO Assurance NOAA Assurance Bus PL WBS 4.0 Satellite (SL) Development Joint SL for Launch #1 SL for Launch #2 NSPO selfreliant SL Science PL Launch IF WBS 5.0 Launch WBS 6.0 Ground & Operations WBS 7.0 Data Processing Figure 8 Joint Collaboration Framework of NSPO and NOAA The detailed scope of work and responsibilities are specified in the JMCP. NSPO s responsibility for Taiwan include systems engineering and design, spacecraft bus development, Launch #1 Launch #2 SL AIT Bus Ground Frequency Coordination Operations PL US DPC Taiwan DPC DPC IF Both NSPO NOAA WBS 8.0 Data Utilization US Data Utilization Taiwan Data Utilization US Data Application Taiwan Data Application 6

7 satellite operation and control, and satellite data processing and utilization. NOAA s responsibilities for the U.S. include launch, ground systems, mission payload, and satellite data processing and utilization. The main execution strategies of this program will be focused in the following four areas: increase of the international research cooperation, establishment of core technology capabilities, strengthening of satellite data processing, and enhancement of data utilization. Recent Events NSPO issued the spacecraft bus Request for Proposal (RFP) in June 2012 that included the Spacecraft Bus s Requirements Document (BSRD), the Payload to Spacecraft bus interface requirements documents (MPL IRDs), Science Payloads to Spacecraft bus interface requirements documents (SPL IRDs), Ground Segment-to- Spacecraft interface requirements documents (GS IRD), and Launch Vehicle-to-Spacecraft interface requirements (LS IRD). the NOAA and CWB s NWP models. This will also result in diminished weather prediction capability that may lead to increased costs and loss of life due to natural disasters. In viewing the need of the constellational global RO data to continue the enhancement of the weather predictions and the climate observations, FORMOSAT-7/COSMIC-2 of the next RO constellation program is implemented to reduce the potential RO data gap and continue to serve the global meteorology community. On the other hand, this system will serve as a verification platform for the GNSS-RO data, and enhance the international collaboration of the GNSS- RO data processing and application, which will promote the greater societal impacts to the livelihood and civil benefits globally.[7] It is certain that the implementation and realization of FORMOSAT-7 operation mission will continue to fulfill this important mission and further increase weather forecast capabilities. Significant efforts from U.S. and Taiwan sides have been contributed to the joint mission, the first launch of FORMOSAT-7 / COSMIC- 2 in 2016 can be expected. Surrey Satellite Technology LTD (SSTL) of United Kingdom is awarded the FORMOSAT-7 Spacecraft Bus Contract in August 2012 through an international fair open bid evaluation. Upon the contract award, SSTL has been moving forward to the preparation of the 1 st ICWG Interface Control Working Group (ICWG) meeting of the space segment and the satellite Design Review (SDR). NSPO with the new spacecraft bus partner, SSTL of U.K., continued to work diligently with the U.S. partners toward the first 6-satellites launch in CONCLUSION FORMOSAT-3 / COSMIC has been on the forefront of radio occultation in constellation measurements for atmosphere and ionosphere and has been regarded as the Most Accurate and Stable Thermometer in Space by the global meteorology community. The research contribution of FORMOSAT-3 mission to weather prediction is considered to be significant by the Taiwan CWB and U.S. NOAA s National Weather Service (NWS), and represents an immense benefit to worldwide forecasting capability. Especially, it provides at least 60% of the assimilated observations for worldwide Numerical Weather Prediction centers for the last 6+ years. Although the FORMOSAT-3 / COSMIC constellation is now several years beyond its initial design life time, NSPO is still providing significant resources to allow the extraction and provision of occultation measurements in Near-Real-Time to continuously serve the global users. This data is not available globally from other sources, and allowing this data to deteriorate due to the FORMOSAT-3 satellites end-oflife will result in a significant diminution of performance of 7 ACKNOWLEDGEMENTS The authors would like to thank the contributions of the FORMOSAT-3/COSMIC program, the FORMOSAT- 7/COSMIC-2 program, systems engineering team; the Taiwan science teams; and the following cooperation partners: NSC, NARL, NSPO, CWB, SSTL, NSF, UCAR, NCAR, JPL/NASA, USAF, and Aerospace Corp. REFERENCES [1] R. A. Anthes, P. A. Bernhardt, Y. Chen, L. Cucurull, K. F. Dymond, D. Ector, S, B. Healy, S.-P. Ho, D. C. Hunt, Y.-H. Kuo, H. Liu, K. Manning, C. McCormick, T. K. Mehan, W. J. Randel, C. Rocken, W. S. Schreiner, S. V. Sokolovskiy, S. Syndergaard, D. C. Thompson, K. E. Trenberth, T. K. Wee, N. L. Yen, and Z. Zeng, The COSMIC/FORMOSAT-3 : Early Results, Bull. Am. Meteoro. Soc., 89, , Mar [2] Y.-A. Liou, A. G., Pavelyev, S.-F., Liu, A. A. Pavelyev, N. L. Yen, C.-Y. Huang, and C.-J. Fong, FORMOSAT-3 GPS Radio Occultation : Preliminary Results, IEEE Trans. on Geosci. and Rem. Sens., 45 (10), , Doi: / TGRS [3] C.-J. Fong, N. L. Yen, C.-H. Chu, S.-K. Yang, W.-T. Shiau, C.-Y. Huang, S. Chi, S.-S. Chen, Y.-A. Liou, and Y.-H. Kuo, FORMOSAT-3/COSMIC Spacecraft Constellation, Results, and Prospect for Follow-on, Terr. Atmos. Ocean. Sci., 20(1), 1 19, Doi: / TAO (F3C).

8 [4] C.-J. Fong, D. Whiteley, E. Yang, K. Cook, V. Chu, B. Schreiner, D. Ector, P. Wilczynski, T.-Y. Liu, and, N. L. Yen, Space and Ground Segment Performance and lessons learned of the FORMOSAT-3/COSMIC : Four Years in Orbit, Atmos. Meas. Tech., 4, Doi: /amt [5] Final Report of the Workshop on the Redesign and Optimization of the Space based Global Observing, ETSAT/SUP3/Doc. 5( (1), Appendix A, WMO Headquarters, Geneva, June [6] L. Cucurull, Assimilation of GPS radio occultation measurements at NCEP. GRAS SAF Workshop on Applications of GPSRO measurements, June (Invited Paper) [7] V. Chu, J. Ling, T Lin., C.-J Fong, F.-T Huang, and G.-S. Chang, FORMOSAT-7/COSMIC-2 Overview, 5th FORMOSAT-3/COSMIC Data Users Workshop and International Conf. on GPS Radio Occultation (ICGPSRO) 2011, Taipei, Taiwan, S9-03. (Invited Paper) [8] K. Cook, P. Wilczynski, C.-J. Fong, N. L. Yen, and G.-S. Chang, The Constellation Observing for Meteorology Ionosphere and Climate Follow-On, 2011 IEEE Aerospace Conf. Proceedings, 1067, Big Sky, MT, 5-12 March [9] C.-J. Fong, N. Yen, C.-H. Chu,.C.-C. Hsiao, Y.-C. Lin, S.-S. Chen, Y.-A. Liou, and S. Chi, In Quest of Global Radio Occultation for Meteorology Beyond 2011, 2009 IEEE Aerospace Conference Proceedings, 1400, Big Sky, MT, 7-14 March [10]C.-J. Fong, N. L. Yen, C.-H. Chu, C.-C. Hsiao, Y.-A. Liou, and S. Chi, Space-based Global Weather Monitoring FORMOSAT-3/COSMIC Constellation and its Follow-On, AIAA J. Spacecraft and Rockets, Vol. 46, No. 4, Jul./Aug. 2009, doi: / [11]N. L. Yen, C.-J. Fong, C.-H. Chu, J.-J. Miau, Y.-A. Liou, and Y.-H. Kuo, Global GNSSS Radio Occultation for Meteorology, Ionosphere & Climate. In: Aerospace Technologies Advancements, edited by Arif, T. T., ISBN , , 2010, INTECH, online available from (Invited Paper) BIOGRAPHY Nick L. Yen has over 30 years of experience in S/C design, analysis, manufacturing, integration, testing, launching, In-Orbit testing. He has over 18 years of direct experience in INTELSAT-7, MABUHAY, APSTAR-IIR, Europe*Star, Sirius operations & management at SS/L, and additional 7+ years FORMOSAT-3 operations & management at NSPO, Taiwan. He has spent over 9 years of directly responsible for S/C-to-L/V integration missions and Launch Base Operations. Mr. Yen has worked at NSPO since 2004 as first the Deputy Director for FORMOSAT-3 and then the Director for the same. Before starting at NSPO, Mr. Yen worked at Space s Loral in Palo Alto, CA as an Antenna Design Engineer, Senior s Engineer, Deputy Executive Director, and MBSAT Antenna Subsystems Manager. Mr. Yen obtained his B.S. in Mechanical Engineering from Tsing-Hua University, Taiwan, in 1976 and his M.S. in Mechanical Engineering from Oregon State University, USA in Currently, He continues to serve at NSPO in the capacity of program management. Chen-Joee Fong is the FORMOSAT- 7/COSMIC-2 s Lead of National Space Organization (NSPO), National Applied Research Laboratory (NARL), Taiwan. He leads a system team to develop a 12 spacecraft constellation mission for global GNSS Radio Occultation (RO) mission for Meteorology, Ionosphere & Climate. He received his BSEE, MSEE, and PhD degree in Electro-physics and Electro-Optical Engineering from National Chiao-Tung University (NCTU), Taiwan, in 1983, 1985, and 2009, respectively. He was a spacecraft lead and responsible for the anomaly resolution team during the FORMOSAT-3/COSMIC mission operation phase in 2006 and was a program system engineering manager for the program from 2002 to He was the FORMOST-3/COSMIC resident team at Orbital Sciences Corp. deom 2002~2003. He joined NSPO in 1993 and later acted as satellite Integration & Test (I&T) project manager of FORMOSAT-1 (aka ROCSAT-1) program and I&T division director. He was assigned to TRW, Inc. to lead the Engineering Development Model (EDM) team in FORMOSAT-1 in 1995 and was promoted as an I&T Test manager. From 1987 to 1993 he worked at Center for Measurement Standards (CMS) as a Microwave Lab head and he was a systems engineer in Center for Aviation and Space Technology (CAST) of Industrial Technology Research Institute (ITRI) for ROCSAT-1 program. His current research interests include Hilbert- Huang Transformation (HHT) for satellite data trending analysis, satellite system on a chip, front-to-end process, 8

9 systems engineering, mission simulation. He is a member of IEEE, AIAA, OSA, AASRC and Phi Tau Phi Guey-Shin Chang is the Director General of National Space Organization (NSPO), National Applied Research Laboratories (NARL), Taiwan, ROC. He is responsible for managing and directing the Taiwan s space program. He earned his BS degree in Civil Engineering from National Central University (NCU), Taiwan in He received the MS and Ph.D. degrees both in Engineering Mechanics of the University of Alabama in 1987 and 1991 respectively. He devoted academic researchers in the areas of computational dynamics, structure dynamics, and numerical analysis in complex systems. He joined NSPO as a systems engineer for the Taiwan s space program in In 1995, he was assigned to Northrop Grumman (former TRW, Inc.) to lead the systems engineering team in FORMOSAT-1. In 1997, he was promoted as Director of s Engineering Division of NSPO. He was successfully leading NSPO s team to accomplish the launch and operations phase of FORMOSAT-1 and the system design phase of FORMOSAT-2. In 1999, He took over the position of Director of Ground Division at NSPO. During his directorship, he had led a project successfully upgraded NSPO s mission operations center into the Multi- Center capable of operating multiple satellites simultaneously. When NARL was established in 2003, He was promoted as Director of Business Development Division, but concurrently served as Director of Ground of NSPO until 2005, responsible for promoting and integrating the NARL s research capabilities among eleven laboratories. He had led several NARL s frontier and innovative research projects including Space-qualified CMOS Image Sensor Development, MEMS-based Micro-satellite Component Development, and 3D GIS Taiwan (a virtual reality satellite imagery platform for environment monitoring & disaster reduction applications). In 2008, He was appointed as Deputy Director General responsible for supervising the NSPO s developing satellite programs. He also served as Director of FORMOSAT-5 to develop the first indigenous high-resolution remote sensing satellite of Taiwan. In April of 2010, He was appointed as Director General of NSPO by NARL with expectation of leading NSPO toward the new era of Taiwan s space programs. Currently, He is responsible for leading a joint US/Taiwan mission of FORMOSAT- 7/COSMIC-2 to deploy a next generation GNSS Radio Occultation satellite constellation system for weather prediction, space weather monitoring, and geodesic research. He is serving as the Academician of International Academy of Astronautics (IAA) as well. 9