Proceedings Volume 7106

Sensors, Systems, and Next-Generation Satellites XII

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Proceedings Volume 7106

Sensors, Systems, and Next-Generation Satellites XII

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Volume Details

Date Published: 2 October 2008
Contents: 14 Sessions, 53 Papers, 0 Presentations
Conference: SPIE Remote Sensing 2008
Volume Number: 7106

Table of Contents

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Table of Contents

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  • Front Matter: Volume 7106
  • US Missions I
  • US Missions II
  • European Missions
  • Japanese Missions I
  • Japanese Missions II
  • Calibration I
  • Calibration II
  • Missions and Sensing Technologies I
  • Missions and Sensing Technologies II
  • FPA I
  • FPA II
  • Applications of Global Earth Observations in Addressing Societal Benefits
  • Poster Session
Front Matter: Volume 7106
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Front Matter: Volume 7106
This PDF file contains the front matter associated with SPIE Proceedings Volume 7106, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.
US Missions I
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NASA's Earth science flight programs
NASA's strategic goal in Earth science is motivated by the fundamental question: "How is the Earth changing and what are the consequences for life on Earth?" NASA's mission in Earth science, as mandated by the Space Act, is to "... conduct aeronautical and space activities so as to contribute materially to ...the expansion of human knowledge of the Earth and of phenomena in the atmosphere and space". Therefore NASA's role is unique and highly complements those of other U.S. Federal agencies (such as the National Oceanic and Atmospheric Administration, National Science Foundation, U.S. Geological Survey, and Environmental Protection Agency) by continually advancing Earth system science from space, creating new remote sensing capabilities, and enhancing the operational capabilities of other agencies and collaborating with them to advance national Earth science goals. Continuous global observations of variability and change are required to reveal natural variability and the forces involved, the nature of the underlying processes and how these are coupled within the Earth system. NASA's Earth Science Division (ESD) provides these observations through its orbital and suborbital Flight Programs. In the decade 2007-2016, ESD will develop and demonstrate new sensors and interacting constellations of satellites to address critical science questions and enable advances in operational capabilities in response to the National Research Council's Decadal Survey of Earth Science and Applications.
The Ocean Surface Topography Mission (OSTM)
The Ocean Surface Topography Mission (OSTM), also known as Jason-2, will extend into the next decade the continuous climate data record of sea surface height measurements begun in 1992 by the joint NASA/Centre National d'Etudes Spatiales (CNES) TOPEX/Poseidon mission and continued by the NASA/CNES Jason-1 mission in 2001. This multi-decadal record has already helped scientists study the issue of global sea level rise and better understand how ocean circulation and climate change are related. With OSTM, high-precision ocean altimetry has come of age. The mission will serve as a bridge to transition the collection of these measurements to the world's weather and climate forecasting agencies. The agencies will use them for short- and seasonal-to-long-range weather and climate forecasting. OSTM is designed to last at least three years. It will be placed in the same orbit (1,336 kilometers) as Jason-1 and will move along the same ground track at an inclination of 66 degrees to the equator. It will repeat its ground track every 10 days, covering 95 percent of the world's ice-free oceans. A tandem mission between Jason-1 and OSTM will be conducted to further improve tide models in coastal and shallow seas, and to better understand the dynamics of ocean currents and eddies. OSTM is an international and interagency mission developed and operated as a four-party collaboration among NASA, the National Oceanic and Atmospheric Administration (NOAA), CNES, and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). CNES is providing the spacecraft, NASA and CNES are jointly providing the payload instruments and NASA is providing the launch vehicle. After completing the onorbit commissioning of the spacecraft, CNES will hand over operation and control of the spacecraft to NOAA. NOAA and EUMETSAT will generate the near-real-time products and distribute them to users. OSTM was launched from Vandenberg Air Force Base, California on June 20, 2008. Launch and Early Orbit Operations (LEOP) and the on-orbit Assessment Phase have been completed. Preliminary science data show excellent performance.
The Orbiting Carbon Observatory: NASA's first dedicated carbon dioxide mission
The Orbiting Carbon Observatory is scheduled for launch from Vandenberg Air Force Base in California in January 2009. This Earth System Science Pathfinder (ESSP) mission carries and points a single instrument that incorporates 3 high-resolution grating spectrometers designed to measure the absorption of reflected sunlight by near-infrared carbon dioxide (CO2) and molecular oxygen bands. These spectra will be analyzed to retrieve estimates of the column-averaged CO2 dry air mole fraction, XCO2. Pre-flight qualification and calibration tests completed in early 2008 indicate that the instrument will provide high quality XCO2 data. The instrument was integrated into the spacecraft, and the completed Observatory was qualified and tested during the spring and summer of 2008, in preparation for delivery to the launch site in the fall of this year. The Observatory will initially be launched into a 635 km altitude, near-polar orbit. The on-board propulsion system will then raise the orbit to 705 km and insert OCO into the Earth Observing System Afternoon Constellation (A-Train). The first routine science observations are expected about 45 days after launch. Calibrated spectral radiances will be archived starting about 6 months later. An exploratory XCO2 product will be validated and then archived starting about 3 months after that.
Aquarius/SAC-D mission
Amit Sen, Daniel Caruso, Gary Lagerloef, et al.
Sea Surface Salinity (SSS) is a key parameter in the global water cycle but it is not yet monitored from space. Conventional in situ SSS sampling is too sparse to give the global view of salinity variability that a remote sensing satellite can provide. The Aquarius/SAC-D Mission will make pioneering space-based measurements of global SSS with the precision, resolution, and coverage needed to characterize salinity variations (spatial and temporal), investigate the linkage between ocean circulation, the Earth's water cycle, and climate variability. It is being jointly developed by NASA and the Space Agency of Argentina, the Comision Nacional de Actividades Espaciales (CONAE). The Project is currently in implementation phase with the flight Aquarius Instrument undergoing environmental testing at NASA-JPL/Caltech in California, USA and the SAC-D instruments and spacecraft development undergoing at CONAE/INVAP facilities in Argentina. Aquarius/SAC-D launch is scheduled for May 2010.
US Missions II
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Global precipitation measurement (GPM) preliminary design
Steven P. Neeck, Ramesh K. Kakar, Ardeshir A. Azarbarzin, et al.
The overarching Earth science mission objective of the Global Precipitation Measurement (GPM) mission is to develop a scientific understanding of the Earth system and its response to natural and human-induced changes. This will enable improved prediction of climate, weather, and natural hazards for present and future generations. The specific scientific objectives of GPM are advancing: Precipitation Measurement through combined use of active and passive remote-sensing techniques, Water/Energy Cycle Variability through improved knowledge of the global water/energy cycle and fresh water availability, Climate Prediction through better understanding of surface water fluxes, soil moisture storage, cloud/precipitation microphysics and latent heat release, Weather Prediction through improved numerical weather prediction (NWP) skills from more accurate and frequent measurements of instantaneous rain rates with better error characterizations and improved assimilation methods, Hydrometeorological Prediction through better temporal sampling and spatial coverage of highresolution precipitation measurements and innovative hydro-meteorological modeling. GPM is a joint initiative with the Japan Aerospace Exploration Agency (JAXA) and other international partners and is the backbone of the Committee on Earth Observation Satellites (CEOS) Precipitation Constellation. It will unify and improve global precipitation measurements from a constellation of dedicated and operational active/passive microwave sensors. GPM is completing the Preliminary Design Phase and is advancing towards launch in 2013 and 2014.
The decadal survey tier 2 missions
Steven P. Neeck, Kenneth W. Jucks, Eric J. Lindstrom, et al.
In January 2007, the National Research Council (NRC) released the first decadal survey addressing Earth science entitled "Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond". The study, initiated in 2004, conducted a decadal survey to generate consensus recommendations from the Earth and environmental science and applications communities regarding a systems approach to the space-based and ancillary observations encompassing the research programs of NASA, the related operational programs of the National Oceanic and Atmospheric Administration (NOAA), and associated programs, such as Landsat, a joint initiative of the U.S. Geological Survey (USGS) and NASA. Among its many recommendations, were that NOAA and NASA should undertake a set of 17 missions, phased over the next decade in three year groupings. Of these 17 missions, 15 were designated to NASA. The four NASA Phase 1 missions are currently in Pre-Phase A study at different levels of development with SMAP, a soil moisture monitoring mission, targeting a launch date of 2013 and ICESat-II, intended to continue the record initiated by ICESat-I to monitor ice sheet height changes for climate change diagnosis, targeting a launch date of 2015. The CLARREO solar and earth radiation monitoring mission and the DESDynI Earth surface and ice deformation monitoring mission are preparing to enter Pre-Phase A in 2009. The five NASA Phase 2 missions are: SWOT, a wide swath altimeter mission measuring ocean, lake, and river water levels; HyspIRI, a hyperspectral mission for measuring land surface composition for agriculture and mineral characterization and vegetation types for ecosystem health; ASCENDS, a day/night, all-latitude, all-season CO2 column measuring mission; ACE, an aerosol and cloud profiling mission for climate and water cycle research with an ocean color measuring capability for open ocean biogeochemistry; and GEO-CAPE, a geostationary mission for measuring atmospheric gas columns for air quality forecasts and ocean color for coastal ecosystem health and climate emissions. Risk reduction and concept maturity studies are underway for these Phase 2 missions with the goal to improve their understanding and scope to enable the Earth Science Division (ESD) to make programmatic decisions for FY10 and beyond. An overview of their science requirements, system concept, technology readiness, and study status will be provided.
European Missions
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Meteosat Third Generation: progress on space segment system feasibility studies: payload aspects
Donny M. Aminou, Hendrik Stark, Wolfgang Schumann, et al.
ESA and EUMETSAT have initiated joint preparatory activities for the formulation and definition of the Meteosat Third Generation (MTG) geostationary system to ensure the continuity and improvement of the Meteosat Second Generation (MSG) system. The MTG will become the new system to be the backbone of the European operational meteorological services from 2015, in particular, will ensure the continuation of the imagery missions. The first phases were devoted to the definition and consolidation of end user requirements and priorities in the field of Nowcasting and Very Short Term Weather Forecasting (NWC), Medium/Short Range global and regional Numerical Weather Prediction (NWP), Climate and Air Composition Monitoring and to the definition of the relevant observation techniques. The following missions have been analysed and preliminary concepts studied: The Flexible Combined Imager, an improvement of the actual MSG-SEVIRI Imager Lightning Imagery Mission IR Sounding Mission UV-VIS-NIR Sounding Mission as a payload complement from GMES. After pre-phase A mission studies (2003-2006), where preliminary instrument concepts were investigated allowing in the same time to consolidate the technical requirements for the overall system study, a phase A study on MTG has been launched at the beginning of February 2007 for the space segment system feasibility and programmatic aspects to be accomplished during 2007-2008 time frame. The space segment phase A study will cover all elements to the level of details allowing to conclude on the feasibility of the system and to produce cost estimates with a good level of confidence. This paper provides an overview of the outcome of the MTG space segment at the end of phase A, addressing the progress accomplished for the various payloads in terms of achievable performances including Radiometry and Image Navigation and Registration aspects. It namely focuses onto the Imaging and IR Sounding, Lightning Missions, introduces the UV-VIS-NIR Sounding mission concept status, establishes the critical technologies and introduces the way forward to the implementation of the MTG development programme.
ESA contribution to the GMES atmosphere monitoring missions
G. Bazalgette Courrèges-Lacoste, M. Arcioni, Y. J. Meijer, et al.
Implementation of operational atmospheric composition monitoring missions is foreseen in the context of the Global Monitoring for Environment and Security (GMES) initiative. Sentinel-4 will address the geostationary and Sentinel-5 the low Earth orbiting part. The two missions are planned to be launched respectively on-board EUMETSAT's METEOSAT Third Generation (MTG) and Post-EPS satellites. Furthermore, a precursor for Sentinel-5 is needed to bridge between the current research missions (ENVISAT, EOS Aura) and Sentinel-5. This paper presents an overview of the GMES Sentinels-4 and -5 (precursor) missions, which have been assessed at Phase-0 level. It will describe the targetted services and key requirements, and outline the main aspects of the candidate implementation concepts now available at completion of Phase-0. It mainly focuses onto the Sentinel-5 precursor mission and the Sentinel-4 mission, highlights the resulting instrument concepts and establishes the critical technologies identified at completion of Phase-0.
Japanese Missions I
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Overview of Japanese Earth observation programs
Four programs, i.e. TRMM, AMSR-E, ASTER, and ALOS are going on in Japanese Earth Observation programs. TRMM and ASTER are operating well, and TRMM operation will be continued at least to 2009. ADEOS2 was failed, but AMSR-E on Aqua is operating. ALOS (Advanced Land Observing Satellite) was successfully launched on 24th Jan. 2006. ALOS carries three instruments, i.e., PRISM (Panchromatic Remote Sensing Instrument for Stereo Mapping), AVNIR-2 (Advanced Visible and Near Infrared Radiometer), and PALSAR (Phased Array L band Synthetic Aperture Radar). PRISM is a 3 line panchromatic push broom scanner with 2.5m IFOV. AVNIR-2 is a 4 channel multi spectral scanner with 10m IFOV. PALSAR is a full polarimetric active phased array SAR. PALSAR has many observation modes including full polarimetric mode and scan SAR mode. After the unfortunate accident of ADEOS2, JAXA still have plans of Earth observation programs. Next generation satellites will be launched in 2008-2013 timeframe. They are GOSAT (Greenhouse Gas Observation Satellite), GCOM-W and GCOM-C (ADEOS-2 follow on), and GPM (Global Precipitation Mission) core satellite. GOSAT will carry 2 instruments, i.e. a green house gas sensor (TANSO-FTS) and a cloud/aerosol imager (TANSO-CAI). The main sensor is a Fourier transform spectrometer (FTS) and covers 0.76 to 15 μm region with 0.2 to 0.5 cm-1 resolution. GOSAT will be launched on beginning of 2008. GPM is a joint project with NASA and will carry two instruments. JAXA will develop DPR (Dual frequency Precipitation Radar) which is a follow on of PR on TRMM. Another project is EarthCare. It is a joint project with ESA and JAXA is going to provide CPR (Cloud Profiling Radar). ALOS F/O satellites are now called disaster monitoring satellites. They are composed of 2 kinds of satellites, SAR and optical satellites. The first one of these disaster monitoring satellites is a SAR satellite and will carry L-band SAR.
ASTER on-board calibration status
Fumihiro Sakuma, Takashi Sato, Hitomi Inada, et al.
The ASTER is a high-resolution optical sensor for observing the Earth on the Terra satellite launched in 1999. The ASTER consists of three radiometers, the VNIR in the visible and near-infrared region, the SWIR in the shortwave infrared region, and the TIR in the thermal infrared region. The on-board calibration devices of the VNIR and the SWIR were two halogen lamps and photodiode monitors. In orbit three bands of the VNIR showed a rapid decrease in the output signal while all SWIR bands remained stable. The temperature of TIR on-board blackbody remains at 270 K in the short-term calibration for the offset calibration, and is varied from 270 K to 340 K in the long term calibration for the offset and gain calibration. The long term calibration showed a decrease of the TIR response in orbit. The radiometric calibration coefficients of the VNIR and the TIR were fit to smooth functions. The temperature of the SWIR detector increased from 77 K to more than 93 K in May 2008 so that the SWIR data saturated thereafter.
Advanced Land Observing Satellite (ALOS): enabling technologies and platform performance
Takanori Iwata, Haruyuki Ishida, Yuji Osawa
The Advanced Land Observing Satellite (ALOS) was launched on January 24, 2006. Since then, it has been operated successfully on orbit, delivering a variety of high-resolution images in numerous quantities and contributing to disaster management support many times. ALOS is a JAXA's flagship for high-resolution Earth observation. It is the Earth observation satellite that is capable of attaining conflicting goals: global data collection and high resolution (2.5m). To attain these goals, a variety of platform and mission technologies were developed. In particular, high-resolution optical sensor technology, phased-array synthetic aperture radar technology, precision attitude and position determination and control technology, and high-speed data handling technology were developed. This paper gives an overview of the ALOS mission and spacecraft with a particular emphasis on the critical platform and mission technologies. This also reviews the last 31 months' operations and on-orbit status of the ALOS spacecraft with the flight data analysis. The assessment and calibration of the mission-related platform performances such as orbit determination and control accuracies, attitude determination and control accuracies, attitude stability, and pixel geolocation determination accuracy are also reported along with our efforts to improve these performances.
PALSAR CALVAL and generation of the continent scale mosaic products for Kyoto and Carbon Project
Masanobu Shimada, Osamu Isoguchi, Ake Rosenqvist, et al.
ALOS has been on orbit for two years and a half after its launch on January 24 2006. After its initial calibration for the first six months, ALOS was thrown into the operational phase after Oct. 23 2006. In operation phase, PALSAR has been activated based on the basic mission operation plan that summarizes the requests for imaging from JAXA calibration team, the power users, Principal Investigator (PIs) of the ALOS Research announcement, and the Kyoto and Carbon initiatives for monitoring the forest deforestation and degradation. By now, ALOS collected the PALSAR data more than 700,000 scenes, which correspond to 8 times global, land coverage. The calibration results using the one year data set shows that PALSAR has an excellent performance of the radiometric accuracy of 0.6 dB using all the corner reflectors associated with the calibration experiments and 0.17 dB using the Swedish 5m sized corner reflectors, the geometric accuracy with 9.3 m (RSS). The polarimetric performance is that the amplitude variation of the VV/HH channels is 0.3 dB and phase is 0.3 degrees. In this paper, we will introduce the stability of the PALSAR calibration results for after operation phase. This covers the stability of the sensor its self and the update of the antenna pattern measurements, SCANSAR processing update, and the suppression of the ground radar interference. We also introduce the generation of the 50 meter spaced ortho-rectified PALSAR mosaic datasets for the Kyoto and Carbon Initiatives. Using the corner reflectors, we have monitored the temporal variation of the accuracies. We have also conducted the antenna pattern variation and the stabilities using the Amazon rain forest data.
Updated results of calibration and validation of ALOS optical instruments
Takeo Tadono, Masanobu Shimada, Junichi Takaku, et al.
This paper describes the updated results of calibration and validation for optical instruments onboard the Advanced Land Observing Satellite (ALOS, nicknamed "Daichi"), which was successfully launched on January 24th, 2006 and it is continuously operating very well. ALOS has an L-band Synthetic Aperture Radar called PALSAR and two optical instruments i.e. the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) and the Advanced Visible and Near Infrared Radiometer type-2 (AVNIR-2). PRISM consists of three panchromatic radiometers, and is used to derive a digital surface model (DSM) with high spatial resolution that is an objective of the ALOS mission. Therefore, geometric calibration is important in generating a precise DSM by stereo pair image of PRISM. AVNIR-2 has four radiometric bands from blue to near infrared and uses for regional environment and disaster monitoring etc. The radiometric calibration and image quality evaluation are also important for AVNIR-2 as well as PRISM. This paper describes updated results of geometric calibration including geolocation determination accuracy evaluation of PRISM and AVNIR-2, image quality evaluation of PRISM, and validation of generated PRISM DSM. These works will be done during the ALOS mission life as an operational calibration to keep absolute accuracies of the standard products.
A conceptual design of Japanese next generation disaster monitoring satellite mission
Tomohiro Watanabe, Shinichi Suzuki, Yuji Osawa
In January 2006, JAXA launched the Advanced Land Observing Satellite (ALOS) "Daichi" by H-IIA #8. Since then, "Daichi" has been operated to support the missions including disaster monitoring, which is one of the important missions, and JAXA has been conducting demonstration experiments for more effective use of remote sensing satellites for disaster mitigation with Japanese government agencies and institutes. Also, requirements to the satellites system for disaster monitoring were summarized, which are prompt observation within 3 hours after a disaster stricken,high resolution and wide coverage by optical sensors and synthetic aperture radars. Rapid monitoring of damaged area becomes more important to keep safety and relief of the people involved in catastrophic disasters. L-band radar wave can penetrate leaves and grasses and measure the ground movement directly, however, anothoer shorter waves (X or C-band radar) has difficulty in penetrating leaves and grasses.For that reason, L-band SAR is most appropriate. This paper introduces a concept and design of satellite system with L-band SAR and optical sensors for the next generation disaster monitoring.
The pre-launch performance test and calibration results of Thermal And Near-infrared Sensor for carbon Observation (TANSO) on GOSAT
Hiroshi Suto, Takahiro Kawashima, Jun Yoshida, et al.
In order to characterize the pre-launch performance of Thermal And Near infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) and Cloud and Aerosol Imager (TANSO-CAI) on the Green house gases Observing SATellite (GOSAT) under the environmental condition on orbit as well as in the laboratory, the Proto Flight Model (PFM) for TANSO-FTS and CAI have been developed. TANSO-FTS has three narrow bands of 0.76, 1.6 and 2.0 micron (Band 1, 2 and 3) with +/-2.5cm maximum optical path difference, and a wide band of 5.5 - 14.3 micron (band 4) in thermal near infrared region. TANSO-CAI is a radiometer for detection and correction of clouds and aerosol effects which might degrade the column concentration retrieval of CO2 and CH4. It has four spectral band regions; ultraviolet (UV), visible, near IR and SWIR. The basic character of TANSO-FTS and CAI, such as the Signal to Noise Ratio (SNR), the polarization sensitivity (PS), Instantaneous Field Of View (IFOV), spectral response, and also Instrumental Line Shape Function (ILSF) have been characterized by introducing the light emitted from the black body, halogen lamp and the tunable diode laser. In addition to these characterizations, micro vibration effect on orbit has been investigated on TANSO-FTS. There prelaunch test results demonstrated that TANSO will provide data for high accuracy CO2 and CH4 retrieval on orbit.
Japanese Missions II
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Airborne SWIR FTS for GOSAT validation and calibration
In order to validate and calibrate TANSO-FTS data of the GOSAT satellite, and also to develop the retrieval algorism for deriving the column density of CO2 and CH4 from spectra, the airborne SWIR (Short Wave Infrared Region) FTS (Fourier transform spectrometer) has been developed, characterized and demonstrated. This instrument is named as TSUKUBA model. The basically performance test of TSUKUBA model was carried out in our laboratory, and the measured modulation efficiencies are 70% (Band1), 85% (Band2) and 88% (Band3), respectively. The measured values of SNR with the equivalent black body temperature for 30% surface albedo are 190 (13050cm-1), 148 (6200cm-1), and 165 (5000cm-1) without polarization measurement. The measured values of full width at half maximum (FWHM) of instrumental line shape functions are 0.38cm-1, 0.26cm-1, 0.25 cm-1 of band 1, 2, and 3, respectively. This instrument is also able to measure the scene flux with P and S polarization, simultaneously, as TANSO-FTS SWIR measures. In 2007, the first and second flight campaigns were arranged and the sunlight reflected spectra over the earth's surface was obtained. This instrument was mounted on high-altitude airplane with image motion compensator and damping platform, and flied over southern Australia and Siberia. The instrumental design and the results of performance tests as well as the flight campaign are presented.
Detailed design of the GOSAT DHF at NIES and data acquisition/processing/distribution strategy
Hiroshi Watanabe, Hironari Ishihara, Kenji Hayashi, et al.
GOSAT Project (GOSAT stands for Greenhouse gases Observation SATellite) is a joint project of MOE (Ministry of the Environment), JAXA (Japan Aerospace Exploration Agency) and NIES (National Institute for Environmental Studies (NIES). Data acquired by TANSO-FTS (Fourier Transform Spectrometer) and TANSO-CAI (Cloud and Aerosol Imager) on GOSAT (TANSO stands for Thermal And Near infrared Sensor for carbon Observation) will be collected at Tsukuba Space Center @ JAXA. The level 1A and 1B data of FTS (interferogram and spectra, respectively) and the level 1A of CAI (uncorrected data) will be generated at JAXA and will be transferred to GOSAT Data Handling facility (DHF) at NIES for further processing. Radiometric and geometric correction will be applied to CAI L1A data to generate CAI L1B data. From CAI L1B data, cloud coverage and aerosol information (CAI Level 2 data) will be estimated. The FTS data that is recognized to have "low cloud coverage" by CAI will be processed to generate column concentration of carbon dioxide CO2 and methane CH4 (FTS Level 2 data). Level 3 data will be "global map column concentration" of green house gases averaged in time and space. Level 4 data will be global distribution of carbon source/sink model and re-calculated forward model estimated by inverse model. Major data flow will be also described. The Critical Design Review (CDR) of the DHF was completed in early July of 2007 to prepare the scheduled launch of GOSAT in early 2009. In this manuscript, major changes after the CDR are discussed. In addition, data acquisition scenario by FTS is also discussed. The data products can be searched and will be open to the public through GOSAT DHF after the data validation process. Data acquisition plan is also discussed and the discussion will cover lattice point observation for land area, and sun glint observation over water area. The Principal Investigators who submitted a proposal for Research Announcement will have a chance to request the specific observation, early standard data delivery and research data delivery.
GOSAT level 1 processing and in-orbit calibration plan
Kei Shiomi, Shuji Kawakami, Tomoko Kina, et al.
Greenhouse gases Observing SATellite (GOSAT) is a Japanese mission to observe greenhouse gases, such as CO2 and CH4, from space. The GOSAT carries a Fourier transform spectrometer and a push broom imager. The development of GOSAT satellite and sensors has almost finished after the characterization of sensor performance in laboratory. In orbit, the observation data will be evaluated by onboard calibration data and implemented by ground processing system. Level 1 algorithm and processing system are developed by JAXA. The post-launch calibration items are planned and the methods are developed before launching. We show the Level 1 processing and in-orbit calibration of GOSAT sensors.
Status of GCOM-W1/AMSR2 development and science activities
Misako Kachi, Keiji Imaoka, Hideyuki Fujii, et al.
Japan Aerospace Exploration Agency (JAXA) is developing the Advanced Microwave Scanning Radiometer-2 (AMSR2). AMSR2 will be onboard the GCOM-W1 satellite, which is the first satellite of the Japan's Global Change Observation Mission (GCOM). The second satellite of GCOM will be GCOM-C1, which will carry the Secondgeneration Global Imager (SGLI). AMSR2 is being developed based on the experience of the AMSR for the EOS (AMSR-E), which is currently in operation on EOS Aqua satellite more than 6-years. The AMSR2 instrument is a dualpolarized total power microwave radiometer system with six frequency bands ranging from 7GHz to 89GHz. Major changes in performance from AMSR-E include the larger antenna diameter of 2.0m for better spatial resolution, additional 7.3GHz channels for mitigating radio-frequency interference, and improvements of calibration system. Engineering model of AMSR2 is being manufactured and tested including performance testing of calibration target in thermal vacuum environment. The GCOM-W1 satellite system finished the preliminary design review before proceeding to Phase-C in June 2008. AMSR2 will observe various water-related geophysical parameters. We expect a long-term continuity by leading the AMSR2 to the current AMSR-E observation that has been accumulating six years of data records. This will contribute to the long-term monitoring of climate variability and daily operational applications. Current target launch year of GCOM-W1 is the beginning of 2012.
Breadboarding activities of the Second-generation Global Imager (SGLI) on GCOM-C
Yoshihiko Okamura, Kazuhiro Tanaka, Takahiro Amano, et al.
The Global Change Observation Mission (GCOM) is the next generation earth observation project of Japan Aerospace Exploration Agency (JAXA). GCOM concept will take over the Advanced Earth Observing Satellite-II (ADEOS-II) and develop into long-term monitoring of global climate change. The observing system consists of two series of medium size satellites: GCOM-W (Water) and GCOM-C (Climate). The Second-generation Global Imager (SGLI) on GCOM-C is a multi-band imaging radiometer in the wavelength range of near-UV to thermal infrared. SGLI will provide high accuracy measurements of Land, Ocean, Atmosphere, and Cryosphere. This paper describes design and breadboarding activities of the SGLI instrument.
Development of the DPR algorithms and products for GPM
Misako Kachi, Shuji Shimizu, Naofumi Yoshida, et al.
Global Precipitation Measurement (GPM) started as an international mission and follow-on and expand mission of the Tropical Rainfall Measuring Mission (TRMM) project to obtain more accurate and frequent observations of precipitation than TRMM. The TRMM satellite achieved ten-year observation in November 2007, and is still operating to measure tropical/subtropical precipitation. An important goal for the GPM mission is the frequent measurement of global precipitation using a GPM core satellite and a constellation of multiple satellites. The accurate measurement of precipitation will be achieved by the Dual-frequency Precipitation Radar (DPR) on the GPM core-satellite, which is being developed by Japan Aerospace Exploration Agency (JAXA) and National Institute of Information and Communications Technology (NICT) and consists of two radars, which are Ku-band precipitation radar (KuPR) and Kaband radar (KaPR). KaPR will detect snow and light rain, and the KuPR will detect heavy rain. In an effective dynamic range in both KaPR and KuPR, drop size distribution (DSD) information and more accurate rainfall estimates will be provided by a dual-frequency algorithm. The frequent precipitation measurement every three hours at any place on the globe will be achieved by several constellation satellites with microwave radiometers (MWRs). JAXA/EORC is responsible for the GPM/DPR algorithm development for engineering values (Level 1) and physical products (e.g. precipitation estimation) (Level 2 and 3) and the quality control of the products as the sensor provider. It is also important for us to produce and deliver frequent global precipitation map in real time in order to make useful for various research and application areas (i.e., the prediction of the floods).
Study for external calibration method for cloud profiling radar on EarthCARE
EarthCARE mission has objectives to reveal aerosol and cloud interaction and to reveal relationships with radiation budget. For this purpose, the EarthCARE satellite has four instruments, which are Atmospheric LIDAR (ATLID), Multi Spectral Imager (MSI) and Broad Band Radiometer (BBR) in addition to Cloud Profiling Radar (CPR). CPR is developed under cooperation of Japanese Aerospace Exploration Agency (JAXA) and National Institute of Information and Communications Technology (NICT) in Japan. The requirement of sensitivity is -35dBZ, therefore CPR uses W-band frequency and needs a large (2.5m) antenna reflector. The large antenna has small footprint and is to give up antenna scanning. From this, some difficulty of external calibration using active radar calibrator (ARC) is recognized. One solution of external calibration is using scattering from natural distributed target, such as sea surface. Then the measurement of sea surface scattering using airborne cloud radar was performed. The sea surface scattering property is being prepared. Second solution is that ARC puts on exact location of sub-satellite track. Precise sub-satellite track prediction is necessary. We focus second solution in this paper. The test experiment was demonstrated using CloudSat of NASA/JPL, which is provided CPR using W-band frequency. The feasibility of this calibration method is discussed.
Calibration I
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Status of Aqua MODIS instrument operation, calibration, and performance
X. Xiong, W. L. Barnes, V. V. Salomonson
Aqua MODIS has successfully operated on-orbit for more than 6 years since its launch in May 2002. MODIS observations are made in 36 spectral bands, which consist of 20 reflective solar bands (RSB) with wavelengths from 0.41 to 2.2μm and 16 thermal emissive bands (TEB) from 3.7 to 14.4μm. As many as 40 science data products have been continuously generated from MODIS observations (Terra and Aqua) and used extensively for studies of global climate and environmental changes. As Aqua MODIS continues to operate beyond its design lifetime of 6 years, we provide in this paper the sensor on-orbit operation and calibration activities and a performance summary. This paper serves as an update for the Aqua MODIS instrument status and presents lessons learned based on its 6-year on-orbit measurements and long-term trending of key sensor performance parameters, including instrument temperature, on-board blackbody and focal plane assembly (FPA) temperatures, and spectral band responses. Discussions will also cover the on-board solar diffuser (SD) operation and degradation analysis. Results show that Aqua MODIS overall on-orbit performance is more stable and better than its predecessor, Terra MODIS, launched in December 1999.
Using Dome C for MODIS calibration and characterization
MODIS is a scanning radiometer that has 36 spectral bands with wavelengths from visible (VIS) to long-wave infrared (LWIR). Its observations and data products have significantly enabled studies of changes in the Earth system of land, oceans, and atmosphere. Currently, there are two nearly identical MODIS instruments operated in space: one on the Terra spacecraft launched in December 1999 and another on the Aqua spacecraft lunched in May 2002. MODIS reflective solar bands (RSB) are calibrated on-orbit by a system that consists of a solar diffuser (SD) and a solar diffuser stability monitor (SDSM) on a regular basis. Its thermal emissive bands (TEB) calibration is executed on a scan-by-scan basis using an on-board blackbody (BB). In addition to on-board calibrators (OBC), well-characterized ground targets have been used by MODIS calibration and validation scientists and by the MODIS Characterization Support Team (MCST) to evaluate and validate sensor on-orbit calibration, characterization, and performance. In this paper, we describe current MCST effort and progress made to examine sensor stability and inter-calibration consistency using observations over Dome Concordia, Antarctica. Results show that this site can provide useful calibration reference for a wide range of Earth-observing sensors.
Examination of calibration performance of multiple POS sensors using measurements over the Dome C site in Antarctica
The Dome C site, located at Dome Concordia in Antarctica, has one of the most homogeneous land surfaces on Earth in terms of reflectance and temperature. An in-situ research-based automatic weather station (AWS) provides a continuous record of surface climate conditions. The extreme cold, dry and clean atmosphere of the site is ideal to collect overpass data for sensor validation and inter-comparison study. This study uses measurements from multiple sensors on-board polar orbiting satellites including both Terra/Aqua MODIS and NOAA-15 to 18 AVHRR that overpass the Dome C site to examine each sensor's long-term calibration stability and biases between two similar sensors. Validation is performed based on observed near-nadir top-of-atmosphere (TOA) reflectances of one visible and near-IR spectral band and brightness temperatures of two atmospheric window bands. Trends of the reflectance show that they are strongly anisotropic and thus a BRDF (bi-directional reflectance distribution) model developed based on near surface reflectance measurements over Antarctic snow surface is applied to normalize the TOA reflectances. The BRDF normalization produces stable trends of reflectance with variations of within 1.5% for Terra/Aqua MODIS and 1% and 2% for NOAA- 16 and 17 AVHRR, respectively. For the atmospheric window bands, observed brightness temperatures are referenced to the same time near-surface temperatures collected at the AWS. Trending results show that the atmospheric window bands are maintained to be stable, while the temperature differences among NOAA-15 to 18 AVHRR are up to 2.0K, compared with small differences of within 0.10K found between Terra and Aqua MODIS.
Degradation pattern of the ERBE wide field-of-view radiometer aboard the NOAA 9 spacecraft
G. Louis Smith, Robert B. Lee III, Takmeng Wong, et al.
An Earth Radiation Budget Experiment wide-field-of-view radiometer aboard the NOAA 9 spacecraft provided measurements of radiation over the globe from February 1985 through December 1992. The shortwave channel, which measured reflected solar radiation, used a quartz dome as a filter. Long exposure to direct sunlight degraded the dome. The combination of NOAA 9 orbit geometry and sensor design resulted in degradation much greater on one side than the other, which affects the calibration, the measurements of solar radiation reflected by the Earth, and the retrieval of albedo. This study includes these three aspects so that the data can be analyzed.
Calibration II
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Calibration of a radiance standard for the NPP/OMPS instrument
James J. Butler, Scott J. Janz, B. Carol Johnson, et al.
In June 2007, a spherical integrating source was calibrated in the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center's (GSFC) Calibration Facility as part of the prelaunch characterization program for the NPOESS Preparatory Program (NPP) Ozone Mapping and Profiler Suite (OMPS) instrument. Before shipment to the instrument vendor, the sphere radiance was measured at the Remote Sensing Laboratory at the National Institute of Standards (NIST) and then returned to the NASA Goddard facility for a second calibration. For the NASA GSFC calibration, the reference was a set of quartz halogen lamps procured from NIST. For the measurement in the Remote Sensing Laboratory, the reference was an integrating sphere that was directly calibrated at NIST's Facility for Spectroradiometric Calibrations (FASCAL). For radiances in the visible and near-infrared (400 nm to 1000 nm), the agreement between the NASA GSFC calibration and the validation measurements at the Remote Sensing Laboratory was at the 1 % level. For radiances in the near ultraviolet (250 nm to 400 nm), the agreement was at the 3 % level.
One point calibration in interferometric radiometers devoted to Earth observation
F. Torres, V. González-Gambau, C. González-Haro
Amplitude calibration has a major impact on the final performance of an interferometric radiometer devoted to Earth observation. This work presents a new method to calibrate the instrument based on a combination of internal and external signals. This so-called "one point" calibration makes use of deep sky views as single external calibration target. This method will be tested in the commissioning phase of the MIRAS/SMOS mission by the European Space Agency, as a back-up of the current calibration approach.
In-flight AHS MTF measurements
The disposal of couples of images of the same landscape acquired with two spatial resolutions gives the opportunity to assess the in-flight Modulation Transfer Function (MTF) of the lower resolution sensor in the common spectral bands. For each couple, the higher resolution image stands for the landscape so that the ratio of the spectra obtained by FFT of the two images, gives the lower resolution sensor MTF. This paper begins with a brief recall of the method including the aliasing correction. The next step presents the data to be processed, provided by the Instituto Nacional de Tecnica Aeroespacial (INTA). The model of the AHS MTF is described. The presentation of the corresponding AHS results naturally follows. Last part of the paper consists in a comparison with other measurements: measurements obtained with the edge method and laboratory measurements.
Radiometric and spectral calibrations of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) using principle component analysis
Jialin Tian, William L. Smith, Michael J. Gazarik
The ultimate remote sensing benefits of the high resolution Infrared radiance spectrometers will be realized with their geostationary satellite implementation in the form of imaging spectrometers. This will enable dynamic features of the atmosphere's thermodynamic fields and pollutant and greenhouse gas constituents to be observed for revolutionary improvements in weather forecasts and more accurate air quality and climate predictions. As an important step toward realizing this application objective, the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) Engineering Demonstration Unit (EDU) was successfully developed under the NASA New Millennium Program, 2000-2006. The GIFTS-EDU instrument employs three focal plane arrays (FPAs), which gather measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw GIFTS interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. The radiometric calibration is achieved using internal blackbody calibration references at ambient (260 K) and hot (286 K) temperatures. The absolute radiometric performance of the instrument is affected by several factors including the FPA off-axis effect, detector/readout electronics induced nonlinearity distortions, and fore-optics offsets. The GIFTS-EDU, being the very first imaging spectrometer to use ultra-high speed electronics to readout its large area format focal plane array detectors, operating at wavelengths as large as 15 microns, possessed non-linearity's not easily removable in the initial calibration process. In this paper, we introduce a refined calibration technique that utilizes Principle Component (PC) analysis to compensate for instrument distortions and artifacts remaining after the initial radiometric calibration process, thus, further enhance the absolute calibration accuracy. This method is applied to data collected during an atmospheric measurement experiment with the GIFTS, together with simultaneous observations by the accurately calibrated AERI (Atmospheric Emitted Radiance Interferometer), both simultaneously zenith viewing the sky through the same external scene mirror at ten-minute intervals throughout a cloudless day at Logan Utah on September 13, 2006. The PC vectors of the calibrated radiance spectra are defined from the AERI observations and regression matrices relating the initial GIFTS radiance PC scores to the AERI radiance PC scores are calculated using the least squares inverse method. A new set of accurately calibrated GIFTS radiances are produced using the first four PC scores in the regression model. Temperature and moisture profiles retrieved from the PC-calibrated GIFTS radiances are verified against radiosonde measurements collected throughout the GIFTS sky measurement period.
Missions and Sensing Technologies I
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The Missile Defense Agency's space tracking and surveillance system
John Watson, Keith Zondervan
The Ballistic Missile Defense System (BMDS) is a layered system incorporating elements in space. In addition to missile warning systems at geosynchronous altitudes, an operational BMDS will include a low Earth orbit (LEO) system-the Space Tracking and Surveillance System (STSS). It will use infrared sensing technologies synergistically with the Space Based Infrared Systems (SBIRS) and will provide a seamless adjunct to radars and sensors on the ground and in airborne platforms. STSS is being designed for a future operational capability to defend against evolving threats. STSS development is divided into phases, commencing with a two-satellite demonstration constellation scheduled for launch in 2008. The demonstration satellites will conduct a menu of tests and experiments to prove the system concept, including the ground segment. They will have limited operational capability within the integrated BMDS. Data from the demonstration satellites will be received and processed by the Missile Defense Space Experiment Center (MDSEC), a part of the Missile Defense Integration and Operations Center (MDIOC). MDA launched in 2007 into LEO a satellite (NFIRE) designed to make near-field multispectral measurements of boosting targets and to demonstrate laser communication, the latter in conjunction with the German satellite TerraSAR-X. The gimbaled, lightweight laser terminal has demonstrated on orbit a 5.5 gbps rate in both directions. The filter passbands of NFIRE are similar to the STSS demonstrator track sensor. While providing useful phenomenology during its time on orbit, NFIRE will also serve as a pathfinder in the development of STSS operations procedures.
Updated status and capabilities for the LOTIS 6.5 meter collimator
Sheldon B. Hutchison, Andrew Cochrane, Shanna McCord, et al.
The Large Optical Test and Integration Site (LOTIS) at Lockheed Martin Space Systems Company (LMSSC) in Sunnyvale, California was designed and constructed in order to allow advanced optical testing for systems up to a maximum aperture of up to 6.5 meters in air or vacuum over a bandwidth of 0.4 to over 5 μm with a design field of view of 1.5 milliradians. Previously reported information for the LOTIS 6.5 meter diameter Collimator was based on data collected during initial testing of this device at the University of Arizona's Steward Observatory Mirror Laboratory. This paper will report progress and new results for the LOTIS Collimator as it is re-assembled and tested during its final integration into its facility at LMSSC. In addition, we will discuss Scene Projection Technology (SPT) capabilities that can be added to provide user test capabilities meeting or exceeding many of the original specifications of the Collimator, primarily in increased optical bandwidth and field-of-view. Finally, we will describe additional optical tools (e.g., interferometers and smaller collimators) that are integral to the LOTIS facility that can provide flexible optical testing options for a wide array of users.
Assembly and test of MEDUSA, a multi-spectral instrument for stratospheric Earth observation
B. Delauré, T. Van Achteren, J. Everaerts, et al.
MEDUSA is a lightweight high resolution camera, designed to operate at stratospheric altitudes mounted on a solar-powered unmanned aerial vehicle (UAV). The MEDUSA instrument targets applications such as crisis monitoring and large scale mapping, requiring high resolution images with regional coverage, flexible flight patterns, high update rates and long mission lengths (weeks to months). The instrument is subject to severe constraints on mass (< 2,5 kg), volume, power consumption and survivability in the stratospheric environment. Operating temperatures within the payload vary over several tens of degrees Celsius over the day-night cycle. Nonetheless, the instrument will be able to provide panchromatic and color images of 30 cm ground resolution at an altitude of 18000 m and a wide swath of 3000m. This ESA-PRODEX (PROgramme de Développement d'Expériences scientifiques) funded project successfully passed the Critical Design Review in September 2007 and the assembly, integration and test (AIT) phase of the subsystems will be finalized by the end of 2008. Subsystem tests include an optical performance verification performed on optical compartment with a test-sensor assembly both at ambient and operational environmental conditions. The electronic subsystems and their interfaces are tested for functionality and performance in the operational temperature and pressure range. From early 2009 onwards, the MEDUSA system will be fully integrated including a custom designed wide swath MEDUSA CMOS frame sensor (10000x1200 pixels). The MEDUSA instrument will be ready for its first flight in spring of 2009. The detailed design of the optical instrument and its performances have been discussed in [1]. In this paper we will give an overview of the AIT status of the MEDUSA sensor and the optical system and an outlook on the system integration and test phase.
Missions and Sensing Technologies II
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Study of two-dimensional scanning LIDAR for planetary explorer
Takahide Mizuno, Makoto Mita, Yasuhiro Kajikawa, et al.
A LIDAR system is an important navigation sensor that can make the long range distance measurements necessary to rendezvous with and touchdown on a target asteroid. More efficient mapping of a planetary surface requires the function of two-dimensional scanning for the purposes of navigation and scientific observation. In this report, we propose a novel scanning system for LIDAR that has a relatively large aperture diameter for long range measurement. The large aperture of the receiver telescope and a frictionless mechanism are realized by means of novel optics and MEMS technology. This report introduces an outline of the two-dimensional scanning LIDAR system and reports the results of fundamental experiments.
Low altitude remote sensing
Daniel Perez Calero, Alan Peyaud, Daphne van der Wal, et al.
In 2007 TNO started to fly some sensors on an unmanned helicopter platform. These sensors included RGB, B/W and thermal infrared cameras. In 2008 a spectrometer was added. The goal for 2010 is to be able to offer a low altitude flying platform including several sensors. Development of these sensors will take place the next years. Since the total weight of the payload should be < 7kg, the weight requirements for the individual sensors will be quite strict. Applications include gas concentrations, water quality, pipelines, etc. Collaboration still is possible. Combining the information of several sensor systems is a difficult task. The first steps have been performed in 2007 where RGB and thermal infrared images have been combined together with the coordinates of the platform itself. The offline data processing includes stitching video images and classification, and correcting for instability of the helicopter itself. As environmental regulation will become even more strict than today, it is expected that high spatial resolution sensors that can measure pollution near highways and urban areas, water quality of rivers and lakes, find and track pollution sources etcetera are key systems in the near future. In September 2007 and April 2008 flight campaigns have been carried out, demonstrating two applications of the system. These include the detection of inland salty water, and the detection of benthic diatoms on an estuarine tidal flat. The results of the two cases are discussed.
DEM from Cartosat data and comparison to DEM from other sources
Until a few years ago DEMs were used only by specialized scientists for terrain analysis, product development and decision making and by the army for military operations planning. Recently the DEM are used in a variety of both commercial and public business and management fields within telecommunications, navigation, constructions, energy, disaster management, transportation, weather forecast, remote sensing, geology, land cover classification, civil engineering and many more. All these applications could be summarised in four major categories: Commercial applications, Industrial applications, Military applications and Environmental-Ecological applications. Thus, there is a huge pressure for very accurate elevation data covering the entire planet surface. Image stereopairs form satellite sensors seem to provide a quite accurate and cost affordable source of elevation data. One of the newest satellite sensors with stereo collection capability is Cartosat. It can acquire stereopairs along the track with a 2,5m spatial resolution covering areas of 30X30km. In this study we compare a DEM created from a Cartosat stereopair to DEM created from other elevation data sources: 1/50.000 topographic maps, SRTM data, airphotos stereo-pair. The area of study is situated in Chalkidiki Peninsula, Greece. After a first control for random or systematic errors a statistical analysis was done. Points of known elevation have been used to estimate the accuracy of these three DEMs. The elevation difference between the different DEMs was calculated. Elevation profiles and derived maps (slope and aspect) were created and compared. 2D RMSE, correlation and the percentile value were also computed and the results are presented.
TROPOMI end-to-end performance studies
Robert Voors, Johan de Vries, Pepijn Veefkind, et al.
The TROPOspheric Monitoring Instrument (TROPOMI) is a UV/VIS/NIR/SWIR non-scanning nadir viewing imaging spectrometer that combines a wide swath (110°) with high spatial resolution (8 x 8 km). Its main heritages are from the Ozone Monitoring Instrument (OMI) and from SCIAMACHY. Since its launch in 2004 OMI has been providing, on a daily basis and on a global scale, a wealth of data on ozone, NO2 and minor trace gases, aerosols and local pollution, a scanning spectrometer launched in 2004. The TROPOMI UV/VIS/NIR and SWIR heritage is a combination of OMI and SCIAMACHY. In the framework of development programs for a follow-up mission for the successful Ozone Monitoring Instrument, we have developed the so-called TROPOMI Integrated Development Environment. This is a GRID based software simulation tool for OMI follow-up missions. It includes scene generation, an instrument simulator, a level 0-1b processing chain, as well as several level 1b-2 processing chains. In addition it contains an error-analyzer, i.e. a tool to feedback the level 2 results to the input of the scene generator. The paper gives a description of the TROPOMI instrument and focuses on design aspects as well as on the performance, as tested in the end-to-end development environment TIDE.
FPA I
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Dynamic PSF and MTF measurements on a 9k TDI CCD
Horst Schwarzer, Anko Boerner, Karl-Heinz Degen, et al.
At the German Aerospace Center (DLR), within the department Optical Information Systems, investigations are currently being performed on time delay and integration charge coupled devices, with respect to their applicability on satellites for earth observing missions. This paper contains first results of dynamic measurements of point spread function and modulation transfer function of a sensor with 9000 pixels and 64 time delay integration steps. The influence of a mismatch between the line synchronisation frequency and satellite ground speed, as well as the effect of angle misalignment between satellite flight direction and the orientation of the sensor itself onto point spread function, and modulation transfer function was investigated. The performance of the test equipment will also be presented.
The Gaia challenge: testing high performance CCDs in large quantities
Andrew Walker, Tim Eaton, Roy Steward, et al.
Gaia, funded by ESA with EADS Astrium as the prime contractor, is an ambitious space observatory designed to measure the positions of around one billion stars with unprecedented accuracy and is currently planned for launch in 2011. The Gaia instrument will feature a focal plane containing 106 large area CCD91-72s manufactured by e2v technologies. This will be the largest CCD focal plane ever flown in space covering an area of 0.286m2. To ensure that the devices meet the required high specification, they undergo significant testing before being accepted by the end user. This involves geometrical, mechanical, environmental, endurance, electrical and electro-optical testing. With the flight phase contract for Gaia requiring the delivery of 130 flight grade devices (plus another 40 engineering devices of various grades), the volume of testing is an order of magnitude greater than and of similar timescale to, the typical space programmes e2v technologies are involved with. This paper will begin by providing an overview of the Gaia mission and the custom CCD91-72 that e2v technologies have designed for it. Next the various phases of the Gaia programme will be outlined and how e2v approached the test requirements for each stage. Problems encountered, lessons learned, and technical and logistical solutions implemented at each stage will be presented, to discuss how e2v technologies improved the quality of the test data whilst reducing the test times. There will be particular emphasis on the electro-optical testing and the test cameras on which this is performed.
Recent developments in very long wave and shortwave infrared detection for space applications
There is considerable interest in sensors which are optimised for detecting infrared radiation outside the normal thermal bands (3-12μm). This paper presents the development of photodiode arrays in Hg1-xCdxTe (MCT) that are sensitive in the very long wave (VLW) band to 14μm or in the visible and SWIR band below 2.5μm wavelength. The VLW arrays are heterostructure diodes fabricated from MCT grown by Metal Organic Vapour Phase Epitaxy (MOVPE). These are staring, focal plane arrays of mesa-diodes bump bonded to silicon read-out circuits. Measurements are presented demonstrating state-of-the-art performance over the temperature range 55-80K, for detectors with a cut-off wavelength of up to 14μm (at 77K). The SWIR/Visible detectors consist of an array of loophole photodiodes fabricated using MCT grown by Liquid Phase Epitaxy (LPE). The technology is suited to imaging LIDAR, NIR/Visible imaging, spectroscopy or hyperspectral applications. The diodes operate as avalanche photodiodes (APDs) which provides near-ideal gain in the pixel. Measurements are presented demonstrating state-of-the-art performance in the range 80K-200K from arrays with a cut-off below 2.5μm. Supporting technologies are also discussed. Silicon circuitry must be implemented in the SWIR and VLW bands that is appropriate to avalanche operation or copes with the low photon flux or low photodiode impedance. Trade-offs between conventional direct injection (DI), buffered direct injection (BDI), pixel capacitive transimpedance amplifier (CTIA) and source-follower per detector (SFPD) are presented. Work is in progress to increase the MOVPE wafer size to 6" which will enable large area arrays to be produced in the SW, MW, LW and VLW bands.
FPA II
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Next generation IR sensor technology for space applications at AIM
K.-M. Mahlein, A. Bauer, H. Bitterlich, et al.
Next generation infrared sensor space applications are based on technological evolutions on many frontiers. Sensor material improvements and device developments are two of them. This presentation reports on the latest results on HgCdTe (MCT) very long wavelength infrared (VLWIR) photovoltaic (PV) sensors and on the development of short wavelength infrared (SWIR) avalanche photodiodes (APDs). The dark current of photodiodes increases exponentially with increasing cut-off wavelength. To keep the dark current at an acceptable level, operational temperatures of MCT PV sensors with photo-sensitivity above 12 μm wavelength are typically around 50 K. Therefore, until recently, VLWIR MCT detectors have been built with photoconductive (PC) linear arrays or small 2D arrays enabling the higher operational temperatures of PC sensors (80 K - 120 K). The increasing interest in VLWIR imaging spectrometers requires larger 2D arrays excluding PC technology. One approach for feasible PV arrays is a significant reduction of the dark current by using extrinsically doped (in contrast to vacancy doped) p-MCT material. This allows for enhanced performance at convenient temperatures of 50 - 55 K. Alternatively, standard performance at higher operational temperatures at 60 K - 70 K is possible. AIM presents the latest results on its extrinsically p-doped VLWIR MCT photodiodes with a 15 μm cut-off wavelength. At the other side of the IR spectrum, AIM has a strong focus on focal plane arrays for low-photon flux SWIR applications. For some applications, the sensitivity of SWIR arrays with capacitive transimpedance amplifier input stages is not sufficient and APDs are required. AIM presents the latest results on its SWIR APD devices.
Enhanced broadband (11-15 µm) QWIP FPAs for space applications
Alexandru Nedelcu, Nadia Brière de l'Isle, Jean-Patrick Truffer, et al.
A thirty months ESA project started in March 2008, whose overall purpose is to expand and assess the performance of broadband (11-15 µm) quantum detectors for spectro-imaging applications: Dispersive Spectrometers (DS) and Fourier Transform Spectrometers (FTS). We present here the technical requirements, the development approach chosen as well as preliminary signal to noise ratio (SNR) calculations. Our approach is fully compatible with the final array format (1024x256, pitch 50-60μm). We expect the requested uniformity, operability and SNR levels to be achieved at the goal temperatures (60K for FTS applications and 50K for DS applications). The performance level will be demonstrated on 256x256, 50µm pitch arrays. Also, operability and uniformity issues will be addressed on large mechanical 1024x256 hybrid arrays.
Latest results of SOFRADIR MCT technology for space applications
Sofradir is developing products for space applications since the early 1990th. Thanks to this experience and based on the different programs conducted up to now, Sofradir became a major supplier for the space industry regarding infrared detectors. Sofradir has developed a robust and versatile technology enabling to address most of the infrared detectors required by space applications. Thus, Sofradir proposes high reliability Mercury Cadmium Telluride (MCT) with different format (off-the-shelf or customized) covering bandwidths from visible to over 15 μm. In this connection, the latest development concerned the extension, characterization and improvement of the MCT technology in visible range for hyperspectral and spectroscopy needs. On the other part of the spectrum, Sofradir is continuing the development of detectors with large cut-off wavelength (above 13 μm) for future space applications like meteorology for example. Finally, a recurrent work is performed by Sofradir concerning the analysis of the compatibility of our infrared detectors with space environment and in particular with radiation environment.
Cheetah: A high frame rate, high resolution SWIR image camera
A high resolution, high frame rate InGaAs based image sensor and associated camera has been developed. The sensor and the camera are capable of recording and delivering more than 1700 full 640x512pixel frames per second. The FPA utilizes a low lag CTIA current integrator in each pixel, enabling integration times shorter than one microsecond. On-chip logics allows for four different sub windows to be read out simultaneously at even higher rates. The spectral sensitivity of the FPA is situated in the SWIR range [0.9-1.7 µm] and can be further extended into the Visible and NIR range. The Cheetah camera has max 16 GB of on-board memory to store the acquired images and transfer the data over a Gigabit Ethernet connection to the PC. The camera is also equipped with a full CameralinkTM interface to directly stream the data to a frame grabber or dedicated image processing unit. The Cheetah camera is completely under software control.
Testing of InGaAs, microbolometer and pyroelectric detectors in support of the EarthCARE mission
Gordon Hopkinson, Luis Gomez Rojas, Mark Skipper, et al.
A test programme for infrared detectors in support of the EarthCARE mission is discussed. Commercially available linear InGaAs arrays from XenICs, Belgium (cut-off wavelengths 1.7, 2.2 and 2.5 μm), 384 x 288 amorphous silicon microbolometer arrays from ULIS, France and un-windowed single element lithium tantalate pyroelectric detectors from Infratec, Germany have been studied in detail to assess their suitability for EarthCARE and to provide performance data to aid in the design of the flight instruments. Tests included radiation resistance (cobalt60 and 60 MeV protons plus a heavy ion latch-up test for the InGaAs and microbolometer arrays), dark signal, noise, output stability, linearity, crosstalk and spectral response. In addition, the pyroelectric detectors were tested for low microphony.
Applications of Global Earth Observations in Addressing Societal Benefits
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Using NASA remote sensing data for coastal monitoring in the northern Gulf of Mexico: a case study
Eurico J. D'Sa, Mitsuko Korobkin, Nan Walker, et al.
The coastal region comprising the states of Louisiana, Mississippi, and Texas is frequently impacted by meteorological events such as frontal passages and hurricanes. The region is also influenced by the Mississippi river, which is seventh largest in terms of water and sediment discharge among the major rivers of the world that strongly influences the physical and biogeochemical properties in the northern Gulf of Mexico. NASA remote sensing data such as winds from QuikSCAT, sea surface height anomaly (SSHA) from Jason-1, ocean color and sea surface temperature (SST) from MODIS satellite sensors were assessed during the period that Hurricane Rita made landfall on 24 September 2005 along the Louisiana-Texas border in the western Gulf of Mexico. QuikSCAT winds revealed the northwestward movement of the hurricane and gradients in the distribution of wind speed around the hurricane center. Altimeter data indicated changes in pattern of the SSH anomaly field and a displacement of the warm and cold core eddies following the hurricane. Although limited by cloud cover, the MODIS 8-day average chlorophyll imagery obtained before and after the hurricane indicated an offshore displacement of higher chlorophyll concentrations while the MODIS 250 m resolution true color imagery showed high levels of suspended particulate matter in the impacted coastal region. MODIS SST indicated a cooling of the surface waters around and east of the track following Hurricane Rita. The use of multiple remote sensing products provided better insights of the oceanographic response to Hurricane Rita.
Poster Session
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Introduction to an airborne remote sensing system equipped onboard the Chinese marine surveillance plane
The airborne remote sensing system onboard the Chinese Marine Surveillance Plane have three scanners including marine airborne multi-spectrum scanner(MAMS), airborne hyper spectral system(AISA+) and optical-electric platform(MOP) currently. MAMS is developed by Shanghai Institute of Technology and Physics CAS with 11 bands from ultraviolet to infrared and mainly used for inversion of oceanic main factors and pollution information, like chlorophyll, sea surface temperature, red tide, etc. The AISA+ made by Finnish Specim company is a push broom system, consist of a high spectrum scanner head, a miniature GPS/INS sensor and data collecting PC. It is a kind of aviation imaging spectrometer and has the ability of ground target imaging and measuring target spectrum characteristic. The MOP mainly supports for object watching, recording and track. It mainly includes 3 equipments: digital CCD with Sony-DXC390, CANON EOS film camera and digital camera Sony F717. This paper mainly introduces these three remote sensing instruments as well as the ground processing information system, involving the system's hardware and software design, related algorithm research, etc.
The development of a specialized processor for a space-based multispectral earth imager
This work was done in the Department of Computer Engineering, Lvov Polytechnic National University, Lvov, Ukraine, as a thesis entitled "Space Imager Computer System for Raw Video Data Processing" [1]. This work describes the synthesis and practical implementation of a specialized computer system for raw data control and processing onboard a satellite MultiSpectral earth imager. This computer system is intended for satellites with resolution in the range of one meter with 12-bit precession. The design is based mostly on general off-the-shelf components such as (FPGAs) plus custom designed software for interfacing with PC and test equipment. The designed system was successfully manufactured and now fully functioning in orbit.
Phase calibration temperature track in interferometric radiometers devoted to Earth observation
V. Gonzàlez-Gambau, F. Torres, N. Duffo
MIRAS (Microwave Imaging Radiometer with Aperture Synthesis), the single payload of the ESA-SMOS mission, consists of a Y-shape interferometric radiometer basically formed by 72 receivers placed along the three arms. Cross-correlations of the signals collected by each receiver pairs "k,j" give the samples of the so-called visibility function, Vkj, which develops into a brightness temperature map by means of a Fourier transform. Therefore, phase errors in the visibility samples are directly translated into image distortion through this Fourier process. The phase is calibrated by injecting correlated noise to its receivers. A method to track phase errors due to temperature gradients has been developed in order to increase the intercalibration period, thus maximizing coverage. Due to the large size of the instrument (arms length around 4 m) and power constraints, moderate thermal swings and thermal gradients within the payload are unavoidable along the orbit. The method presented in this work shows how the visibility phase errors are decoupled into receiver phase errors that can be tracked in temperature. Experimental tests show how decoupling must deal with phase-wrapping problems and cope with the interferometric inherent problem of setting a phase reference in a temperature changing environment.
Analysis of EMC tests for interferometric radiometers
V. González-Gambau, F. Torres, F. J. Benito, et al.
The Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) [1] is the single payload of the SMOS (Soil Moisture and Ocean Salinity) mission of the European Space Agency (ESA), to be launched on spring 2009 [2]. MIRAS performance was successfully tested during spring 2007 by the prime contractor, EADS-CASA Espacio Spain, at ESA premises in ESTEC and after payload integration with the Proteus platform at Thales Alenia Space in Cannes, France. This work presents the results of specific tests designed to assess the impact of a number of possible operating conditions and/or perturbations on MIRAS system performance. The major challenge to easily assess the impact of any perturbation comes from the large number of measurements that have to be dealed with.
Performance improvement and characterization activities for an imaging Fabry-Perot interferometer
Allen M. Larar, William B. Cook, Michael A. Flood, et al.
Risk mitigation activities for a prototype imaging Fabry-Perot Interferometer (FPI) system, development originating within NASA's Instrument Incubator Program (IIP) for enabling future space-based atmospheric composition missions, are continuing at NASA Langley Research Center. The system concept and technology are focused on observing tropospheric ozone around 9.6 micron, but also have applicability toward measurement of other trace species in different spectral regions and other applications. The latest results from performance improvement and laboratory characterization activities will be reported, with an emphasis placed on testing performed to evaluate system-level radiometric, spatial, and spectral measurement fidelity.
Evaluation of land surface reflectance and emissivity spectra retrieved from MASTER data
Takashi Sugisaki, Hideyuki Tonooka
The MODIS/ASTER (MASTER) airborne simulator which has fifty bands in the visible to the thermal-infrared spectral regions was developed mainly to support the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) and the Moderate resolution Imaging Spectroradiometer (MODIS) instrument teams in the areas of algorithm development, calibration and validation, but its wide spectral capability is also useful for other studies such as geology, environmental monitoring, and land management. Currently, only MASTER product distributed to users is a level-1B at-sensor radiance product, so that if a user needs surface reflectance and/or emissivity/temperature, the user should apply atmospheric correction to a level-1B product. Thus in the present study, we derived surface reflectance and emissivity spectra from MASTER data acquired over Railroad Valley Playa, NV/USA, by atmospheric correction with various atmospheric sources like Aerosol Robotic Network (AERONET) products, and then compared with in-situ measured spectra for both reflective and emissive regions. Calibration errors in the reflective region which caused discrepancy from the in-situ spectra were reduced by adjusting the MASTER radiance to ASTER and MODIS radiances at the top of the atmosphere. We also compared the spectral similarity in the reflective region versus that in the emissive region, for MASTER spectra, and the spectra of ASTER spectral library and in-situ spectra, as an example of discrimination analysis using both reflective and emissive bands.