Proceedings Volume 7474

Sensors, Systems, and Next-Generation Satellites XIII

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Proceedings Volume 7474

Sensors, Systems, and Next-Generation Satellites XIII

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Volume Details

Date Published: 5 October 2009
Contents: 14 Sessions, 63 Papers, 0 Presentations
Conference: SPIE Remote Sensing 2009
Volume Number: 7474

Table of Contents

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Table of Contents

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  • Front Matter: Volume 7474
  • European Missions
  • US Missions
  • Japanese Missions I
  • Japanese Missions II
  • Japanese Missions III
  • Calibration I
  • Calibration II
  • FPA I
  • FPA II
  • Missions and Sensing I
  • Missions and Sensing II
  • Applications of Global Earth Observations in Addressing Societal Benefits
  • Poster Session
Front Matter: Volume 7474
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Front Matter: Volume 7474
This PDF file contains the front matter associated with SPIE Proceedings Volume 7474, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.
European Missions
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Sentinel-1 CSAR mission status
Paul Snoeij, Evert Attema, Malcolm Davidson, et al.
The Sentinel-1 synthetic aperture radar (SAR) constellation represents a completely new approach to SAR mission design by ESA in direct response to the operational needs for SAR data expressed under the EU-ESA Global Monitoring for Environment and Security (GMES) programme. The Sentinel-1 constellation is expected to provide near daily coverage over Europe and Canada, and weekly global coverage all independent of weather with delivery of radar data within 1 hour of acquisition - all vast improvements with respect to the existing SAR systems. In addition to responding directly to current needs of the GMES program, the design of the Sentinel-1 satellite mission with its focus on stability, reliability, global coverage, consistent operations and quick data delivery is expected to enable the development of new applications and meet the evolving needs of GMES, for instance in the area of climate change and associated monitoring needs. It is expected that Sentinel-1A will be launched in 2012.
Sentinel-2 optical high resolution mission for GMES land operational services
Ferran Gascon, Philippe Martimort, François Spoto
In the framework of the Global Monitoring for Environment and Security (GMES) programme, the European Space Agency (ESA) in partnership with the European Union (EU) is developing the Sentinel-2 optical imaging mission devoted to the operational monitoring of land and coastal areas. The Sentinel-2 mission is based on a twin satellites configuration deployed in polar sun-synchronous orbit and designed to offer a unique combination of systematic global coverage, high revisit (five days at equator with two satellites) and high spatial resolution imagery (10/20/60m). The Multispectral instrument features 13 spectral bands, going from visible to short wave infrared domains. The instrument is designed to provide in orbit calibration, excellent radiometric and geometric performance, and with a capability to support accurate image geolocation and co-registration. The Sentinel-2 mission is more particularly tailored to the monitoring of land terrains, including vegetation and urban areas. Sentinel-2 will ensure data continuity with the SPOT and Landsat multi-spectral sensors, while accounting for future service evolution.
Sentinel-3 payload overview
U. Klein, B. Berruti, F. Borde, et al.
In order to meet Earth observation needs of the European Union-ESA Global Monitoring for Environment and Security (GMES) programme, ESA decided to develop the Sentinels as first series of operational satellites. The series of Sentinel-3 satellites will provide global, frequent and near-realtime ocean, ice and land monitoring. It continues Envisat's altimetry, the multispectral, medium-resolution visible and infrared ocean and landsurface observations of ERS, Envisat and Spot, and includes enhancements to meet the operational revisit requirements and to facilitate new products and evolution of services. The first launch is expected in 2013. In this paper the design of the major instruments and their basic performance parameters will be introduced as well as the expected accuracies of the main data products.
Meteosat Third Generation (MTG) status of space segment definition
Donny M. Aminou, D. Lamarre, H. Stark, 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 future continuity, and enhancement, of the current Meteosat Second Generation (MSG) system. The MTG programmatics are being established to ensure a seamless transition between the conclusion of the successful MSG operational system and the start of the new MTG operational system, with particular emphasis on continuity of the imagery missions. The MTG phase A studies were successfully concluded in December 2008 an re-consolidation phase B1 activities continued from January to July 2009. They were devoted to the MTG concept definition and requirements consolidation for meeting the User needs in the field of Nowcasting and Very Short Term Weather Forecasting (NWC), Medium/Short Range global and regional Numerical Weather Prediction (NWP), Climate, Air Quality and Composition Monitoring. The following missions have been analysed, measurement techniques studied and preliminary concepts established: - High Resolution Fast Imagery Mission (improved successor to MSG SEVIRI HRV mission) - Full Disk High Spectral Resolution Imagery Mission (improved successor to SEVIRI) - Lightning Imagery Mission - IR Sounding Mission - UV-VIS-NIR Sounding Mission Both space segment architecture and preliminary satellite and instrument concepts were investigated in the course of these studies, and a dual satellite configuration established comprising the Imaging satellite (MTG-I) and the sounding satellite (MTG-S). The study covered all elements to a level of detail allowing to establish a technical baseline, conclude on the feasibility of the system requirements and undertake preliminary programmatic evaluation. Riders to the Phase A studies (Phase B1 work) have been placed to further consolidate the satellite and payload definition and development, prior to the release of the Invitation To Tender (ITT) for the full space segment implementation in July 2009. This paper provides an overview of the conclusions of those MTG space segment studies. It summarises the conclusions reached for the satellites, and associated instruments relating to Imaging, IR Sounding and Lightning missions, with respect to achievable performances, including Radiometry and Image Navigation and Registration aspects.
Meteosat Third Generation (MTG) critical technology pre-development activities
ESA and EUMETSAT have initiated joint preparatory activities for the formulation and definition of the Meteosat Third Generation (MTG) geostationary system to ensure the future continuity, and enhancement, of the current Meteosat Second Generation (MSG) system. The MTG programmatics are being established to ensure a seamless transition between the conclusion of the successful MSG operational system and the start of the new MTG operational system, with particular emphasis on continuity of the imagery missions. The MTG phase A studies were successfully concluded in December 2008 an re-consolidation phase B1 activities continued from January to July 2009. They were devoted to the MTG concept definition and requirements consolidation for meeting the User needs in the field of Nowcasting and Very Short Term Weather Forecasting (NWC), Medium/Short Range global and regional Numerical Weather Prediction (NWP), Climate, Air Quality and Composition Monitoring. The following missions have been analysed, measurement techniques studied and preliminary concepts established: - High Resolution Fast Imagery Mission (improved successor to MSG SEVIRI HRV mission) - Full Disk High Spectral Resolution Imagery Mission (improved successor to SEVIRI) - Lightning Imagery Mission - IR Sounding Mission - UV-VIS-NIR Sounding Mission Both space segment architecture and preliminary satellite and instrument concepts were investigated in the course of these studies, and a dual satellite configuration established comprising the Imaging satellite (MTG-I) and the sounding satellite (MTG-S). The study covered all elements to a level of detail allowing to establish a technical baseline, conclude on the feasibility of the system requirements and undertake preliminary programmatic evaluation. Riders to the Phase A studies (Phase B1 work) have been placed to further consolidate the satellite and payload definition and development, prior to the release of the Invitation To Tender (ITT) for the full space segment implementation in July 2009. This paper provides an overview of the critical technologies as established in the course of MTG space segment studies. It summarises the undertakings carried out for pre-developing the necessary technologies for the associated instruments relating to Imaging, IR Sounding and Lightning missions. It provides the status of the pre-development activities including long wave IR detectors, cryo-coolers, cryogenic wiring, scan mechanism assemblies, LI detectors and narrow band filters.
TROPOMI, the solar backscatter satellite instrument for air quality and climate, heads towards detailed design
Johan de Vries, Robert Voors, A'gnes Mika, et al.
The Tropospheric Monitoring Instrument (TROPOMI) is currently planned for launch on ESA's Sentinel 5 precursor satellite in the time frame of 2014. TROPOMI is an ultraviolet-to-SWIR wavelengths imaging spectrograph that uses two-dimensional detectors to register both the spectrum and the swath perpendicular to the flight direction. The swath is about 110 degrees wide to allow daily global coverage from the polar orbit of the Sentinel 5 precursor satellite. The instrument follows the heritage of SCIAMACHY (ENVISAT, launch 2002) and OMI (AURA, launch 2004), but it has been improved in several ways: the ground resolution is down to 7 x 7 km2, the instrument is fit for low albedo scenes and the wavelength bands are optimized using the SCIAMACHY and OMI heritages to have the best trace gas products. The first two improvements basically mean that the instrument aperture is much larger for TROPOMI and, related to this, the reading of the detectors much faster. The selected wavelength bands for TROPOMI are UV1 (270-310 nm), UV2 (310 - 370 nm), VIS (370 - 500 nm), NIR (675 - 775 nm) and SWIR (2305 - 2385 nm). The first three bands are very similar to the OMI bands, the NIR has been added to improve on clouds and air mass corrections and the SWIR allows measuring CH4 and CO. The paper discusses the development status on several topics, such as detector selection and polarization scrambler performance simulations using the TIDE grid based level 2 scene simulator.
Sustainable satellite constellation development, calibration and on-orbit results
O. Hawkins, L. Sills, S. Mackin
A novel and challenging requirement for a satellite constellation was realised in 2002 with the launch of the Disaster Monitoring Constellation. Following six years of operations, demand for the resource continues to grow, requiring the launch of new sensors. This paper explores the past and future capacity of the constellation and the implications on the calibration and validation activities for this multi-sensor system. The launch of three similar satellites with 22m GSD and one satellite with 2.5m GSD to join the existing satellites with 32m GSD creates complications for the calibration procedures and operational scenarios proposed for the future system. This analysis is performed to guarantee the full utilisation of the constellation to satisfy the requirements of data users. The implications of the broad application of standardised calibration procedures within the context of diverse satellite sensors are considered. The operational scenarios of the constellation are evaluated along with the planned calibration regimes to be conducted in the interests of data continuity. The new sensor designs are compared to analyse the impact on calibration and validation activities.
US Missions
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NASA's Earth science missions overview
Earth is a complex and dynamic system we do not yet fully understand. The Earth system, like the human body, is comprised of diverse components that interact in complex ways. We need to understand the Earth's atmosphere, lithosphere, hydrosphere, cryosphere, and biosphere as a single connected system. Our planet is changing on all spatial and temporal scales. The purpose of NASA's Earth science program is to develop a scientific understanding of Earth's system and its response to natural or human-induced changes, and to improve prediction of climate, weather, and natural hazards. NASA's role is unique and highly complements those of other U.S. Federal agencies (such as the National Oceanic and Atmospheric Administration (NOAA), National Science Foundation (NSF), U.S. Geological Survey (USGS), and Environmental Protection Agency (EPA)) 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. International collaborations are also a feature of many of these NASA Earth science activities. 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. Currently, NASA has 15 operating Earth science space missions with 6 more in development and 9 under study. In the next decade, 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.
Aquarius/SAC-D Mission: preparations towards launch
Amit Sen, Daniel Caruso, David Durham, et al.
The primary objective of the Aquarius/SAC-D earth-remote sensing mission will be to investigate the links between global water cycle, ocean circulation and climate. Sea Surface Salinity (SSS) is a key parameter in understanding the global water cycle and this mission will yield an unprecedented view of ocean's role in climate and weather. This international partnership mission involving 6 countries is preparing for a launch in September 2010. The observatory (spacecraft and Instruments), will accommodate the primary NASA provided instrument for measuring SSS and various instruments from CONAE, ASI, CSA and CNES making additional atmospheric and environmental science measurements. The observatory integration and testing occurs in Argentina and Brazil and launched to space from United States. The project is currently in the final phases of Integration of the Observatory in Argentina and will undergo environmental tests at the INPE-LIT test facility in Brazil before shipping to launch site in USA. An overview of the mission along with the preparation status towards launch will be provided.
CERES FM-5 on the NPP spacecraft: continuing the Earth radiation budget climate data record
The Clouds and the Earth's Radiant Energy System (CERES) Flight Model-5 (FM-5) instrument will fly on the NPOESS Preparatory Project spacecraft, which has a launch-readiness date of no earlier than June, 2010. This mission continues the critical Earth Radiation Budget Climate Data Record begun by the Earth Radiation Budget Experiment instruments in the mid 1980's and continued by the CERES instruments currently flying on the Terra and Aqua spacecraft. This paper outlines lessons learned on the existing CERES instruments from 30+ years of flight experience and presents a radiometric protocol to ensure that the FM-5 instrument performance exceeds the calibration and stability goals.
Progress in developing a geostationary AMSU
The "Precipitation and All-weather Temperature and Humidity" (PATH) mission is one of the 15 NASA "decadalsurvey" missions recommended by the U.S. National Research Council in 2007 and will implement the first microwave sounder in geostationary orbit. This is possible with a new sensor being developed at the Jet Propulsion Laboratory, the Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR). Adequate spatial resolution is achieved by using aperture synthesis instead of a large parabolic reflector as is used in conventional systems. A proof-of-concept prototype was developed at JPL in 2005 under the NASA Instrument Incubator Program and used to demonstrate that this new concept works well at sounding frequencies. Another IIP effort is now under way to advance key technology required for a full space system. The maturity of the concept and technology is now such that mission development could be initiated in 2010-11. The possibility of flying GeoSTAR as an "instrument of opportunity" on NOAA's new series of "GOES-R" geostationary weather satellites is being actively pursued. Other low-cost options are under study as well. PATH/GeoSTAR will provide a number of measurements that are key in monitoring and predicting hurricanes and severe storms - including hemispheric 3-dimensional temperature, humidity and cloud liquid water fields, rain rates and rain totals, tropospheric wind vectors, sea surface temperature, and parameters associated with deep convection and atmospheric instability - everywhere and all the time, even in the presence of clouds - and will also provide key measurements related to climate research.
Japanese Missions I
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Overview of Japanese Earth Observation programs
Five programs, i.e. TRMM, AMSR-E, ASTER, ALOS and GOSAT are going on in Japanese Earth Observation programs. ASTER has lost its short wave infrared, but other satellites/sensors are operating well, and TRMM operation will be continued at least to 2012. 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. GOSAT (Greenhouse Gas Observation Satellite) was successfully launched on 29, January, 2009. GOSAT carries 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. After the unfortunate accident of ADEOS2, JAXA still have plans of Earth observation programs. Next generation satellites will be launched in 2011-2014 timeframe. They are, GCOM-W and GCOM-C (ADEOS-2 follow on), and GPM (Global Precipitation Mission) core satellite. 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 divided into two satellites, i.e. SAR and optical satellites. The first one of ALOS F/O is called ALOS 2 and will carry Lband SAR, while second one is called ALOS3 and will carry optical sensors.
Validation of precise digital surface model generated by PRISM onboard ALOS
Takeo Tadono, Masanobu Shimada, Junichi Takaku
This paper describes the generation of precise digital surface model (DSM) and its validation using the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS, nicknamed "Daichi"), which was successfully launched on January 24, 2006, and has worked very well more than 3.5 years. PRISM performs along-track triplet stereo observations with a forward-, nadir-, and backward-looking radiometer with 2.5 m ground resolution at nadir in a 35 km-wide swath. It is used to derive a precise DSM or digital elevation model (DEM) with high spatial resolution. The sensor calibration is very important in achieving the precise DSM generation using PRISM stereo pair images. This paper introduces updated calibration results of ALOS optical instruments, focusing on PRISM, and including time trends of accuracy improvements. We have achieved 7.8 m (RMSE) of absolute geometric accuracy of the PRISM nadirlooking radiometer. The validation of generated PRISM DSM is shown using reference DSM acquired by airborne Lidar. The height accuracy of the PRISM DSM has achieved 5.2 m (RMSE). Based on these calibration and validation results, we also investigate the validation of the global DEM (GDEM) produced by ASTER onboard the TERRA satellite that was released on June 29, 2009 using generated DSMs by PRISM in terms of global evaluations.
On-orbit performance and level 1 data processing of TANSO-FTS and CAI on GOSAT
The Greenhouse gases Observing SATellite (GOSAT) monitors carbon dioxide (CO2) and methane (CH4) globally from space. It is a joint project of Japan Aerospace Exploration Agency (JAXA), Ministry of the Environment (MOE) and National Institute for Environmental Studies (NIES). GOSAT is placed in a sun-synchronous orbit of 666km and 12:48 local time, with an inclination angle of 98 deg. It was launched on January 23, 2009 from Tanegashima Space Center. There are two instruments on GOSAT. The Thermal And Near infrared Sensor for carbon Observation Fourier- Transform Spectrometer (TANSO-FTS) detects the Short wave infrared (SWIR) reflected on the earth's surface as well as the thermal infrared (TIR) radiated from the ground and the atmosphere. TANSO-FTS is capable of detecting wide spectral coverage; three narrow bands (0.76, 1.6, and 2 μm) and a wide band (5.5-14.3 μm) with 0.27 cm-1 spectral resolution. The TANSO Cloud and Aerosol Imager (TANSO-CAI) is a radiometer of ultraviolet (UV), visible, and SWIR to correct cloud and aerosol interference. For three months after the launch, the on-orbit function and performance have been checked out. Now level 1A (raw interferogram) and level 2B (spectra) are now being processed and provided regularly with calibration data.
Initial results of GOSAT TANSO calibration
Kei Shiomi, Tomoko Kina, Shuji Kawakami, et al.
Greenhouse gases Observing SATellite (GOSAT) is a Japanese mission to observe greenhouse gases, such as CO2 and CH4, from space with a Fourier transform spectrometer and a push broom imager. The GOSAT was launched on January 23, 2009. The initial functional check-out phase was completed on April 10 to confirm the on-orbit performance. The initial calibration and validation phase was completed on July 30 in the following 3 months to acquire observation data at calibration and validation sites. The initial calibration was evaluated on accuracies of radiometry, geometry and spectrometry by using acquired data. The results were reflected to the improvement of the Level 1 algorithm and the products. The initial calibrated Level 1 products have been already released to the GOSAT research PIs in August.
Japanese Missions II
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Upper-atmospheric CO2 concentration retrieved from thermal infrared spectra observed using GOSAT TANSO-FTS (TIR) sensor
The greenhouse gas observing satellite (GOSAT) was launched on 23 January 2009. Its main sensor, the "thermal and near infrared sensor for carbon observation Fourier transform spectrometer (TANSO-FTS)", is functioning normally. It can measure a wide spectrum including three CO2 absorption bands at 1.6 μm and 2.0 μm (Short Wavelength InfraRed, SWIR band), and 15 μm (Thermal InfraRed, TIR band). The former two bands are used to estimate columnar concentrations of CO2. The latter is used to retrieve the vertical profile of CO2 concentration in the upper troposphere. Simulation studies show that high radiometric calibration accuracy of 0.3 K in brightness temperature Tbb is necessary to retrieve a CO2 concentration profile with accuracy of 1% in the upper atmosphere. The sensor's fundamental performance was evaluated during the initial checkout period, which continued for six months. Results show that most of the radiometric performance is achieved as designed. However, results also show that some systematic biases exist in the TIR spectrum because of the opacity of the dichroic mirrors of SWIR bands obstructing the field of view of the TIR band. These biases can be mostly removed by explicitly considering radiation--that emitted from inside of the optics and multiple scattering of target signals--in the calibration procedure. Using a three-day global composite of the clear sky spectrum, CO2 concentrations in the upper atmosphere were retrieved preliminarily. Results show a convincing hemispheric concentration gradient, which agrees well with the climatologic distribution of CO2.
Current status of GOSAT higher level products by NIES GOSAT DHF
Hiroshi Watanabe, Hironari Ishihara, Kenji Hayashi, et al.
GOSAT ( Ibuki ) was successfully launched on January 23, 2009 and has been operating nominally. NIES GOSAT DHF ( Data Handling Facility) , receiving GOSAT Level 1 data of TANSO-FTS ( Fourier Transform Spectrometer) and TANSO-CAI ( Cloud and Aerosol Imager), started checking them and generating Higher Level Products of GOSAT. The Products include Level 1B and 1B+ of CAI and Level 2 ( CO2 and CH4 column amount from SWIR and TIR from FTS and , cloud flag, aerosol and cloud properties from CAI).
Long-term observations of water and climate by AMSR-E and GCOM-W
Misako Kachi, Keiji Imaoka, Hideyuki Fujii, et al.
The Global Change Observation Mission (GCOM) consists of two satellite observing systems and three generations to achieve global, comprehensive, and long-term Earth monitoring. The first satellite of the GCOM-W (Water) series will be GCOM-W1 with the Advanced Microwave Scanning Radiometer-2 (AMSR2) onboard. AMSR2 is a successor of AMSR on the Advanced Earth Observing Satellite-II (ADEOS-II) and AMSR for EOS (AMSR-E) on NASA's Aqua satellite. Basic performance of AMSR2 will be similar to that of AMSR-E based on the minimum requirement of data continuity of AMSR-E, with several enhancements including larger main reflector (2.0 m), additional channels in C-band receiver, and improved calibration system. Development of the GCOM-W1 satellite and sensor system is going quite smoothly. The satellite system is now in Phase-C and finished the CDR No.1 in July 2009. The CDR No.2 is scheduled in autumn 2009 for reviewing the additional items. The AMSR2 instrument is now in Phase-D and the flight model is being manufactured. Retrieval algorithms are being developed by collaboration with principal investigators for the eight standard products and possible research products. Experiences through the AMSR-E research activities and the data themselves can be directly utilized in the AMSR2 algorithm development. AMSR-E continues its observation nearly seven years. Taking over from the AMSR-E observations to GCOM, we will be able to construct over 20-years data set of unique geophysical parameters including all-weather sea surface temperature and soil moisture content. Current target launch year of GCOM-W1 is in Japanese fiscal year 2011.
Development status of the Second-Generation Global Imager (SGLI) on GCOM-C
Kazuhiro Tanaka, Yoshihiko Okamura, Takahiro Amano, et al.
The Second-generation Global Imager (SGLI) on the Global Change Observation Mission (GCOM) is a multi-band imaging radiometer in the wavelength range of near-UV to thermal infrared. SGLI will provide high accuracy measurements of Ocean, Atmosphere, Land and Cryosphere. SGLI project successfully completed its Bread Board Model (BBM) evaluation last year and currently under Engineering Model (EM) development phase. This paper describes current development status of the SGLI instrument.
Development status of cloud profiling radar for EarthCARE
Hirotaka Nakatsuka, Hiroaki Horie, Kazuyuki Okada, et al.
Global three-dimensional cloud distributions and their properties are important information to estimate the earth radiation budget more precisely. The interactions between cloud particles and aerosols are also focused to improve accuracies of climate model. In order to meet expectations of scientists developing climate models for global warming problem, European and Japanese space agencies plan to launch a satellite called EarthCARE. The Cloud Profiling Radar (CPR), which will be the first millimeter-wave Doppler radar in space, is installed on this satellite as one of main sensors to observe clouds. This paper describes the latest design and development status of EarthCARE CPR.
Status of algorithm development and CAL/VAL plans in the JAXA GPM project
The Global Precipitation Measurement (GPM) started as an international project and a follow-on and expansion of the Tropical Rainfall Measuring Mission (TRMM). The GPM mission consists of two different categories of satellites. One is a TRMM-like core satellite carrying both active and passive microwave instruments, jointly developed by Japan and the US. The other is a constellation of satellites carrying passive microwave sensors and provided by partner agencies. A Dual-frequency Precipitation Radar (DPR) for the GPM core satellite is being developed by JAXA and NICT, and consists of Ku- and Ka-band precipitation radars to measure light rainfall and snowfall as well as moderate-to-heavy rainfall. One major objectives of GPM is to contribute to operational utilization, and frequent and accurate precipitation products, at less than 3-hour intervals, will be produced by combining multi-satellite microwave radiometers and geostationary IR information. DPR will provide accurate rainfall database to microwave radiometers, and enhance their algorithms, which will be used to make frequent rainfall map. The DPR L1 algorithms are being developed by JAXA. Collaboration activities between Japan and the US have started to develop L2/3 rainfall algorithms for DPR, and DPR/GMI combined products. Research activities to develop algorithms for rainfall map products have been underway both in Japan and the US. Validation activities in JAXA will be focused on contributions to algorithm development before and after the launch, as well as evaluation of the quality of rainfall products. Pre-launch validation will include ground-based campaigns and utilization of synthetic data produced by numerical models.
Overview of Japan's Advanced Land Observing Satellite-2 mission
Shinichi Suzuki, Yuji Osawa, Yasushi Hatooka, et al.
The post-ALOS program has been defined in the basic plan for Japan's space policy which was established by the Strategic Headquarters for Space Policy on June 2nd, 2009. It emphasizes the continuity of the ALOS mission not only disaster monitoring but also land infrastructure management, earth environment and resource monitoring and so on. JAXA had completed the System Definition Review of the ALOS-2 satellite and ground system in February, 2009 and started phase B design of the new L-band SAR, satellite and ground system with the target launch in 2013.This paper introduces the mission and major specification of ALOS-2 satellite and L-band SAR.
Conceptual design of Advanced Land Observing Satellite-3
Hiroko Imai, Tomohiro Watanabe, Haruyoshi Katayama, et al.
The Advanced Land Observing Satellite (ALOS) "Daichi" launched in January 2006 has been operated successfully on orbit for more than 3 years, delivering a huge number of high-resolution images and contributing to a variety of fields that include disaster management support and regional environment monitoring. Consequently, the Japan Aerospace Exploration Agency (JAXA) is planning the ALOS follow-on program. The ALOS follow-on program consists of two satellites: one is a radar satellite called ALOS-2, the other is an optical satellite called ALOS-3. ALOS-3 will produce pan-sharpened images as a base map of the Geographical Information System (GIS) in systematic observation. ALOS-3 will also promptly provide precise images for determining the damage of a disaster-stricken area in an emergency observation because one of the most important missions of ALOS-3 is disaster monitoring. Some observation capabilities are required to be upgraded from ALOS. ALOS has a panchromatic band with 2.5 m resolution. To provide precise observation data, ALOS-3 has been improved to have a high resolution better than 1 m and 50 km or wider swath. JAXA has been conducting the conceptual design and defining the system requirements for the spacecraft and the mission instrument for ALOS-3.
Japanese Missions III
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JEM/SMILES observation capability
Yasuko J. Kasai, Philippe Baron, Satoshi Ochiai, et al.
A new generation of sub-millimeter-wave receivers employing sensitive SIS (Superconductor-Insulator- Superconductor) detector technology will provide new opportunities for precise passive remote sensing observation of minor constituents in atmosphere. Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) was designed to be onbord the Japanese Experiment Module (JEM) on the International Space Station (ISS) as a collaboration project of National Institute of Information and Communications Technology (NICT) and Japan Aerospace Exploration Agency (JAXA). SMILES scheduled to be launch in September 11, 2009 by the H-II Transfer Vehicle (HTV). Mission Objectives are: i) Space demonstration of superconductive mixer and 4-K mechanical cooler for the submillimeter limb emission sounding, and ii) global observations of atmospheric minor constituents. JEM/SMILES will allow to observe the atmospheric species such as O3, H35Cl, H37 Cl, ClO, BrO, HOCl, HO2, and HNO3, CH3CN, and Ozone isotope species with the precisions in a few to several tens percents from upper troposphere to the mesosphere. We have estimated the observation capabilities of JEM/SMILES. This new technology may allow us to open new issues in atmospheric science.
Sub-millimeter wave radiometer for observation of cloud ice: a proposal for Japanese mission
Jana Mendrok, Dong L. Wu, Stefan A. Bühler, et al.
Ice clouds play an important role in the energy budget of the atmosphere as well as in the hydrological cycle. Currently cloud ice is one of the largest remaining uncertainties in climate models. Large discrepancies arise from different assumptions on ice cloud properties, in particular on microphysics, which are not sufficiently constrained by measurements. Passive sub-millimeter wave (SMM) techniques have the potential of providing direct information on ice content and particle sizes with daily global coverage. Here we introduce a concept for a compact 2-receiver SMM sensor and demonstrate its capabilities on measurements of ice content, mean particle size, and cloud altitude.
Calibration I
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Radiometric calibration of MERIS
Steven Delwart, Ludovic Bourg
The paper intends to describe the operational processing of the MERIS Radiometric Calibration. An overview of the instrument, the principles of its radiometric calibration and an outline of the calibration processing chain are presented. The various models used within the calibration processing are described and discussed. A status of the error budgets and uncertainties of on-ground and in-flight measurements, of models performances, and finally of the expected radiometric accuracy is given.
MODIS thermal emissive band detector bias
B. N. Wenny, X. Geng, X. Xiong
Two nearly identical MODIS instruments are currently operating in space: one on the Terra spacecraft launched in December 1999 and another on the Aqua spacecraft launched in May 2002. MODIS has a total of 36 spectral bands, 16 of which are the Thermal Emissive Bands (TEB) with wavelengths covering from 3.7μm to 14.4μm. Each TEB has 10 detectors aligned in the along-track direction with a spatial resolution of 1km. The 10 detectors view the Earth each scan over a 2330km wide swath. The curvature of the Earth creates a bowtie effect with each scan. At large scan angles consecutive scans will have several detectors with overlapping fields of view. This paper applies two approaches to investigate any potential bias between the 10 detectors of any TEB. A histogram approach is applied to large relatively uniform scenes over the Antarctic plateau, ocean and desert. Results are compared with an approach using the sets of matched detector pairs due to the bowtie effect. Terra and Aqua MODIS TEB long term trends in detector biases are presented and discussed.
MODIS thermal emissive band calibration stability derived from surface targets
The 16 MODIS Thermal Emissive Bands (TEB), with wavelengths covering from 3.7μm to 14.4μm, are calibrated using scan-by-scan observations of an on-orbit blackbody (BB). Select Earth surface targets can be used to track the long-term consistency, stability and relative bias between the two MODIS instruments currently in orbit. Measurements at Dome C, Antarctica have shown a relative bias of less than 0.01K over a 5 year period between Terra and Aqua MODIS Band 31 (11μm). Dome C surface temperatures are typically outside the MODIS BB calibration range. Sea surface temperature (SST) measurements from data buoys provide a useful reference at higher scene temperatures. This paper extends the techniques previously applied only to Band 31 to the remaining TEB using both Dome C and SST sites. The long-term calibration stability and relative bias between Terra and Aqua MODIS is discussed.
Error analysis of CERES instrument edition 3 data products
The Clouds and Earth's Radiation Energy System Project is flying two instruments on both the Terra and Aqua spacecraft. In order to produce highly accurate measurements of the Earth's radiation budget, several calibration and validation techniques are employed on the ground and in orbit. Three editions of data products are generated, with modifications made in successive editions to reduce or eliminate errors. Edition 3 incorporates changes based on these tests, which include comparisons of the various channels on both spacecraft. Use of measurements comparing the different channels of the various instruments causes any remaining errors in the instrument data products to be related among the channels. An error analysis is presented which uses information theory to account for the many tests and checks to give the errors of the instrument data products and the correlations among them in the Edition 3 instrument data products.
RapidEye constellation relative radiometric accuracy measurement using lunar images
Joe Steyn, George Tyc, Keith Beckett, et al.
The RapidEye constellation includes five identical satellites in Low Earth Orbit (LEO). Each satellite has a 5-band (blue, green, red, red-edge and near infrared (NIR)) multispectral imager at 6.5m GSD. A three-axes attitude control system allows pointing the imager of each satellite at the Moon during lunations. It is therefore possible to image the Moon from near identical viewing geometry within a span of 80 minutes with each one of the imagers. Comparing the radiometrically corrected images obtained from each band and each satellite allows a near instantaneous relative radiometric accuracy measurement and determination of relative gain changes between the five imagers. A more traditional terrestrial vicarious radiometric calibration program has also been completed by MDA on RapidEye. The two components of this program provide for spatial radiometric calibration ensuring that detector-to-detector response remains flat, while a temporal radiometric calibration approach has accumulated images of specific dry dessert calibration sites. These images are used to measure the constellation relative radiometric response and make on-ground gain and offset adjustments in order to maintain the relative accuracy of the constellation within ±2.5%. A quantitative comparison between the gain changes measured by the lunar method and the terrestrial temporal radiometric calibration method is performed and will be presented.
Cross-comparison of the IRS-P6 AWiFS sensor with the L5 TM, L7 ETM+, & Terra MODIS sensors
As scientists and decision makers increasingly rely on multiple Earth-observing satellites to address urgent global issues, it is imperative that they can rely on the accuracy of Earth-observing data products. This paper focuses on the crosscomparison of the Indian Remote Sensing (IRS-P6) Advanced Wide Field Sensor (AWiFS) with the Landsat 5 (L5) Thematic Mapper (TM), Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+), and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. The cross-comparison was performed using image statistics based on large common areas observed by the sensors within 30 minutes. Because of the limited availability of simultaneous observations between the AWiFS and the Landsat and MODIS sensors, only a few images were analyzed. These initial results are presented. Regression curves and coefficients of determination for the top-of-atmosphere (TOA) trends from these sensors were generated to quantify the uncertainty in these relationships and to provide an assessment of the calibration differences between these sensors.
Concatenation of terrestrial reference standard sites for systematic post-launch calibration monitoring of multiple space-based imaging sensors
P. M. Teillet, N. P. Fox
The CEOS Quality Assurance Framework for Earth Observation (QA4EO) depends critically on vicarious calibration or cross-calibration to verify the post-launch radiometric calibration performance of satellite optical sensors. Reference standard test sites constitute the only practical means of accomplishing this on a systematic basis. Members of the CEOS WGCV IVOS are working with collaborators around the world to establish a core set of CEOS-endorsed, globally-distributed, reference standard test sites, as well as to establish optimum methodologies for their characterisation and use. This paper proposes a pilot project that would involve the concatenation of as many of the CEOS-endorsed core reference standard test sites as possible during a given time period to generate updates for as many satellite optical sensors as possible. The authors of this paper propose to serve as coordinators and recommend that key specialists, whose identities will be hidden, will carry out the calibration processing, analysis, and comparisons.
Recent progress on cross-comparison of terra and aqua MODIS calibration using Dome C
For the past few years, the MODIS Characterization Support Team (MCST) at NASA/GSFC has continued and extended its effort to monitor the Terra and Aqua MODIS calibration long-term stability and to examine their calibration consistency using observations made over the Dome Concordia, Antarctica. Early results from Dome C observations show that the calibration of bands 1 and 2 (0.65 and 0.86 micron) has been consistent within 1-2% and bands 31 and 32 (11 and 12 micron) differences are less than a few tenths of Kelvin, demonstrating that this site can provide a useful calibration reference for a wide range of Earth-observing sensors in the spectral region from visible (VIS) to long-wave infrared (LWIR). Recently, several locations at the Dome C area have been endorsed by the CEOS as radiometric reference sites for sensor cross-comparison. This, as a result, has led to an invitation to the broad earth-observing community to participate in a CEOS comparison of top-of-atmosphere (TOA) spectral radiance/reflectance over the Dome C sites. In this paper, we provide a brief description of the methodologies applied in our study and report recent progress on cross-comparison of Terra and Aqua MODIS spectral bands using observations over the Dome C area, including data provided in support of the upcoming CEOS sensor cross-comparison.
Calibration II
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A vacuum-compatible flat plate radiometric source for system-level testing of optical sensors
In this work, development of a fiber-optically coupled, vacuum-compatible, flat plate radiometric source applicable to the characterization and calibration of remote sensing optical sensors in situ in a thermal vacuum chamber is described. Results of thermal and radiometric performance of a flat plate illumination source in a temperature-controlled vacuum chamber operating at liquid nitrogen temperature are presented. Applications, including use with monochromatic tunable laser sources for the end-to-end system-level testing of large aperture sensors, are briefly discussed.
Traceable calibration of radiation sources from the visible to the far infrared for space borne applications at PTB
The Physikalisch-Technische Bundesanstalt (PTB) has developed dedicated instrumentations and methods for the traceable calibration of space borne instruments in terms of the three fundamental radiometric units, i.e. spectral radiance (radiation temperature), spectral radiant intensity and spectral photon flux. The traceable calibration under conditions similar to the space environment is achieved by use of two major radiometric calibration facilities of PTB, the Spectral Radiance Comparator Facility (SRCF) and the Reduced Background Calibration Facility (RBCF) which are part of the Primary Temperature Radiator Facility of PTB and cover the wavelength range from the UV to the FIR (THz range). The improved detector instrumentations of the SRCF and RBCF, detailed calibration schemes and results of calibrations for space missions are presented.
The reduced background calibration facility for detectors and radiators at the Physikalisch-Technische Bundesanstalt
The Physikalisch-Technische Bundesanstalt (PTB) operates a Reduced Background Calibration Facility (RBCF) which provides traceable calibrations of space based infrared remote sensing experiments in terms of radiation temperature and spectral radiance. Traceable measurements from space require the use of calibrated stable detector systems and/or calibration standards on board of the satellites. In any case they should be calibrated under space like conditions to ensure traceability at a minimized uncertainty. This is possible with the RBCF which enables the calibration of radiators and detectors under cryogenic and/or vacuum conditions. The general concept of the RBCF is to connect several sources and detectors under vacuum via a liquid nitrogen cooled beamline. The beamline connects a source- with a detector chamber which also incorporate cooling facilities. Translation units in both chambers enable the RBCF to compare and calibrate different sources and detectors at cryogenic temperatures and under a common vacuum. The radiation of the reference sources and the source under test can additionally be imaged on a vacuum Fourier- Transform Spectrometer (FTIR) to allow spectrally resolved measurements. The FTIR covers the wavelength range from 0.4 μm to 1000 μm. Here several detectors are employed, ranging from an Si-Photodiode to a liquid helium cooled Sicomposite bolometer. Two reference blackbody radiators enable measurements with respect to two reference temperatures, simultaneously. Hereby a compensation of background radiation can be performed and the measurement of very faint sources becomes possible.
FPA I
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Two-dimensional VLWIR arrays for Meteosat 3rd generation
S. Hanna, A. Bauer, H. Bitterlich, et al.
The mission success of the geostationary operational satellite system Meteosat Third Generation (MTG) will significantly depend on the instrument performance in the very long wavelength infrared (VLWIR) spectral range. As far as dark current behavior, homogeneity, and operability are concerned, the VLWIR constitutes a major challenge for sensor material improvement and device development. This paper reports on the latest results on HgCdTe (MCT) VLWIR photovoltaic sensor development and characterization for possible use with MTG. In order to achieve low enough dark currents, extrinsically p-doped MCT material with various cut-off wavelengths in the long wavelength infrared (LWIR)/VLWIR has been developed and manufactured. Compared to standard intrinsic MCT, a reduction in dark current by more than an order of magnitude is achieved, meeting the challenging MTG requirements. In a (256x256) VLWIR MCT focal plane array (FPA) with an ~14.7μm cut-off wavelength at a 55K operating temperature, a dark current density of about 1pA/μm2 is demonstrated. For a 291K reference scene and at half-well integration capacity, we obtain a noise equivalent temperature difference of (24.0±3.0)mK and a photo response of 13mV/K.
Development of an SWIR multispectral detector for GMES/Sentinel-2
Aurélien Dariel, Philippe Chorier, Cédric Leroy, et al.
Within the European Global Monitoring for Environment and Security (GMES) program, the Sentinel-2 mission will provide multi-spectral observations of the Earth surface. The Multi-Spectral Instrument (MSI) developed by Astrium, on board the Sentinel-2 satellite, includes a SWIR channel. Sofradir is in charge of the development, qualification and manufacturing of the infrared detector basis of this SWIR channel. This development relies on Sofradir heritage in terms of design and production of infrared detectors for space applications, and is based on the building blocks validated by Sofradir in the frame of ESA breadboarding program for SWIR hyper-spectral detector development. What's more, the detector relies on the use of a high reliability 15 μm pitch hybrid Mercury Cadmium Telluride (MCT) technology. Each Sentinel-2 SWIR detector (12 detectors/instrument x 2 satellites) is comprised of an MCT elementary detector including 3 detection lines with a length of 1298 pixels with 15 μm pitch for detection in the 1.3-2.3 μm range, and is integrated into a compact sealed package filled with helium. This device will be used in the 170-200K range. This paper describes the design of the Sentinel-2 SWIR detector. It also presents the performances and the first tests carried out on representative models.
Sofradir SWIR hyperspectral detectors for space applications
Yoanna-Reine Nowicki-Bringuier, Philippe Chorier
The field of SWIR detectors for space applications is strongly growing those last years, mainly because of the increasing need for environmental missions in the SWIR detection range. For now more than 10 years, Sofradir is involved in that field, developing and improving its SWIR detectors technology, leading to a mature technology that enable to address most of missions needs in term of performances, but also with respect to hard environmental constraints. SWIR detection range at Sofradir has been qualified for space applications thanks to various programs already run (APEX or Bepi-Colombo programs) or currently running (Sentinel 2, PRISMA mission). For Sentinel 2, a 1280x3 with a 15μm pitch in the SWIR range (CTIA) has been developed and is currently being validated. 1000x256 or 500x256 arrays 30 μm pitch (called Saturn or Neptune detectors) have already been validated in terms of irradiation behavior, thermal cycling, and ageing. Specific package designs have been validated in terms of high levels of shocks and vibrations. In particular, for both Sentinel 2 and PRISMA programs, Sofradir has developed reliable packaging compatible with passive cooling. Recently, for PRISMA mission, Sofradir is extending its VISible to Short wave Infra-Red technology, called VISIR, to 1000x256 hyperspectral arrays. This technology has the huge advantage to enable detection in both visible and short wave detection range (0.4μm up to 2.5μm), thus limiting the number of needed channels for hyperspectral applications but also outshining the classical limitation of Silicon Visible detectors, for which the sensitivity is dramatically dropping above 0.9 μm. In this paper, we will focus on hyperspectral detectors available at Sofradir. Main general performances will be first described, with emphasize on the VISIR technology that has been recently developed and which enable to cover simultaneously the Visible and SWIR ranges [0.4-2.5μm] with a single detector. Then some complete configurations (Focal Plane Array integrated in a Detector Dewar) suitable for airborne or space applications will be presented. Finally, a brief overview of reliability and tolerance to radiations of those detectors will be given.
FPA II
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Enhanced broadband (11-15 µm) QWIP FPAs for space applications
Alexandru Nedelcu, Ybe Creten, Nadia Brèire de l'Isle, et al.
A thirty months European Space Agency project started in March 2008, whose overall purpose is to expand and assess the performance of broadband (11-15μm) quantum detectors for spectro-imaging applications: Dispersive Spectrometers and Fourier Transform Spectrometers. We present here the development approach and the progress status concerning the detector layer and read-out circuit. For Dispersive applications a 42K operating temperature is currently achieved, which can still be increased, to approach the 50K goal value. For FTS applications efficient broadband optical coupling is demonstrated.
A visible and NIR multilinear array dedicated to Sentinel 2 Multi Spectral Imager
Michel Bréart de Boisanger, Olivier Saint-Pé, Franck Larnaudie, et al.
Sentinel 2 is an EU/ESA LEO Earth observation mission currently developed in the framework of Global Measurement Environment and Security (GMES) program. The associated Multi Spectral Imager instrument is equipped with about 230 mm length VNIR and SWIR Focal Plane Arrays, each one being made of twelve detectors mechanically butted in staggered configuration. Each elementary VNIR detector features tens spectral bands with 10m, 20m or 60m spatial sampling, ranging from about 430 to 900 nm. The devices are currently manufactured using a 0.35 μm CMOS process optimised for imaging application and already space qualified, thanks to Astrium COBRA family development. For each spectral band, minimum SNR corresponding to reference flux and maximum integration time is required. Maximum flux and minimum MTF are also specified. The photo detector charge to voltage conversion factors and geometrical shapes have therefore been adjusted band per band in order to meet all these competing specifications. In addition, a per pixel Correlated Double Sampling readout circuit has been implemented to cancel photodiode reset noise, providing mean total readout noise lower than 200μV, and the output voltage swing has been improved in view of maximizing the device dynamics. Black coating has been deposited between the simple or double lines of photo detectors in order minimizing straight light effects. After a description of the multi linear detector architecture and functionality, its main performances will be presented. The current status of the industrial development will also be depicted.
Monolithic and hybrid backside illuminated active pixel sensor arrays
Two types of backside illuminated CMOS Active Pixel Detectors--optimized for space-borne imaging--have been successfully developed: monolithic and hybrid. The monolithic device is made out of CMOS imager wafers postprocessed to enable backside illumination. The hybrid device consists of a backside thinned and illuminated diode array, hybridized on top of an unthinned CMOS read-out. Using IMEC's innovative techniques and capabilities, 2-D arrays with a pitch of 22.5 μm have been realized. Both the hybrid and well as the monolithic APS exhibit high pixel yield, high quantum efficiency (QE), and low dark current. Cross-talk can be reduced to zero in the hybrid sensors utilizing special structures: deep-isolating trenches. These trenches physically separate the pixels and curtail cross-talk. The hybrid imagers are suitable candidates for advanced "smart" sensors envisioned to be realized as multi-layer 3D integrated systems. The design of both these types of detectors, the key technology steps, the results of the radiometric characterization as well as the intended future developments will be discussed in this paper.
Total dose, displacement damage, and single event effects in the radiation hardened CMOS APS HAS2
Dirk Van Aken, Dominique Hervé, Matthieu Beaumel
Experimental results of several radiation test campaigns performed on the HAS2 CMOS imager are presented. The radiation testing includes Cobalt-60 total ionizing dose at low and high dose rate, proton and electron displacement damage, proton induced single event transient, and heavy ion single event effect. HAS2 electro-optical performances have been characterized during irradiation at low and room temperature, and after annealing at low, room and high temperature. The gathered data are consistent with radiation hardness properties of the HAS2 sensor. The most significant radiation drift coefficients have been assessed for dark current and electrical offsets. Transient signal under proton flux has been characterized at various proton energies. Robustness to single event latch-up has been demonstrated up to 79 MeV.cm2/mg.
10000 pixels wide CMOS frame imager for earth observation from a HALE UAV
B. Delauré, S. Livens, J. Everaerts, et al.
MEDUSA is the lightweight high resolution camera, designed to be operated from a solar-powered Unmanned Aerial Vehicle (UAV) flying at stratospheric altitudes. The instrument is a technology demonstrator within the Pegasus program and targets applications such as crisis management and cartography. A special wide swath CMOS imager has been developed by Cypress Semiconductor Cooperation Belgium to meet the specific sensor requirements of MEDUSA. The CMOS sensor has a stitched design comprising a panchromatic and color sensor on the same die. Each sensor consists of 10000*1200 square pixels (5.5μm size, novel 6T architecture) with micro-lenses. The exposure is performed by means of a high efficiency snapshot shutter. The sensor is able to operate at a rate of 30fps in full frame readout. Due to a novel pixel design, the sensor has low dark leakage of the memory elements (PSNL) and low parasitic light sensitivity (PLS). Still it maintains a relative high QE (Quantum efficiency) and a FF (fill factor) of over 65%. It features an MTF (Modulation Transfer Function) higher than 60% at Nyquist frequency in both X and Y directions The measured optical/electrical crosstalk (expressed as MTF) of this 5.5um pixel is state-of-the art. These properties makes it possible to acquire sharp images also in low-light conditions.
Design of image sensors for hyperspectral applications
Paul Jerram, David Burt, David Morris, et al.
The sensor design for Hyperspectral observation is significantly different to many other imaging applications and the various requirements are discussed. An early programme is the MERIS (Medium Resolution Imaging Spectrometer) instrument on ENVISAT, which has been producing high quality Hyperspectral images for the last 7 years. The requirements for MERIS originally led to the development at e2v of both back-thinning technology, to meet the spectral requirements, and the manufacture of devices with a graded antireflection coating, to fully optimize the QE at every spectral band. A number of other hyperspectral missions are being planned or in preparation. For example Sentinel 3 is to be an almost direct repeat of the MERIS instrument and will be followed by Sentinel 4 and 5. In the future as the technology matures it is likely that Hyperspectral missions will tend to use CMOS sensors rather than CCD. CMOS sensors have a number of potential advantages for Hyperspectral imaging and if these can be successfully exploited then enhanced performance would result. The design of a CMOS sensor is discussed that is targeted at Hyperspectral application to give fully optimized performance at all spectral bands.
The asteroid finder focal plane
H. Michaelis, S. Mottola, E. Kührt, et al.
The DLR Institute of Planetary Exploration has proposed a novel design for a space instrument accommodated on a small satellite bus (SSB) that is dedicated to the detection of inner earth objects (IEOs) from a low earth orbit (LEO). The low pointing stability of the satellite bus, the stray light and thermal environment in LEO represent the major design drivers for achieving the required limiting magnitude of 18.5 (V-band). In order to cope with the design drivers, DLR has proposed a novel focal plane consisting of four Electron Multiplying CCDs (EMCCD) and their associated electronics.
First demonstration and performance of AlGaN based focal plane array for deep-UV imaging
J.-L. Reverchon, S. Bansropun, J. A. Robo, et al.
We present several prototypes to extend the range of AlGaN focal plane arrays from near UV to deep UV range (200 nm - 4 nm). Arrays include 320x256 pixels with a pitch of 30 μm and are based on Schottky photodiodes. AlGaN is grown on a silicon substrate. After a flip-chip hybridization, silicon substrate is thinned and removed by dry etching. The tricky point is to maintain the membrane integrity. By using a honeycomb structure in the Si substrate, after hybridization, we were able to keep the membrane plane and rigid, avoid the crack expansion, and thus maintain the membrane integrity. The structure includes an Al.35Ga.65N active layer grown on a thick Al.55Ga .45N window layer, with a graded AlGaN layer in between. The high quality materials are grown by MBE. The Al.55Ga.45N window layer is also thinned by dry etching down to the gradual layer and desertion layer where a higher internal electric field takes place. The results show that the dry etching process doesn't affect the readout circuit properties. The dark current is negligible and non uniformity in etching slightly contributes into a constant offset. The measured noise factor, a bit more than 100 electrons rms, is due to reset noise in the integration capacitance and in other parasitic capacitances. With a peak response at 300 nm of 35%, the responsivity is 1% at 266 nm and in the deep UV range. The spectral responsivity measured on a synchrotron line at a wavelength of 2nm reaches more than 200% due to multiple photoexcitation.
Missions and Sensing I
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Laboratory characterisation of the MEDUSA optical system for multi-spectral earth observation from a stratospheric HALE UAV
B. Delauré, S. Livens, J. Everaerts, et al.
MEDUSA is the lightweight high resolution camera, designed to be operated from a solar-powered Unmanned Aerial Vehicle (UAV) flying at stratospheric altitudes. It targets applications such as crisis management and cartography as a technology demonstrator within the Pegasus program. From an operational altitude of 18 km MEDUSA will deliver images with a ground sampling distance of 30 cm and cover a swath of 3 km. The innovative UAV poses high demands on the instrument characteristics such as mass (< 2,5 kg), volume and power consumption. Furthermore the MEDUSA instrument design needs to guarantee its optical performance within the specific environmental conditions of the stratosphere. Well limited chromatic aberrations require the use of anomalous partial dispersion glass. Those glasses unfortunately suffer from large variations of their refractive index as well as their volume with temperature, causing strong focus variations of the optical system. Furthermore, the weight constraints impose compact system (minimizing the distance between lenses for mount weight reduction) and very thin lenses. Manufacturing each of the lenses was challenging. The very thin aspherical lens has required few manufacture iterations to achieve sufficiently low waviness, after that it became clear that this lens was the dominant factor for image contrast limitation. After all subsystem tests have been completed the MEDUSA shall be integrated and finish its ground test program in autumn 2009. This paper will describe the results of the laboratory characterization of the optical system and an outlook on the MEDUSA instrument development.
Hyperspectral architecture study for land management
Timothy N. Miller, Raymond M. Bell Jr., Douglas B. Helmuth, et al.
Remote-sensing hyperspectral sensors operating in the reflective bands offer the opportunity to vastly improve land management worldwide by providing continuous coverage and continuity of satellite capability. We assess the requirements for such sensors that will provide the needed revisit rates, coverage and imaging performance. From these requirements we select a range of potential system-level architectures, and derive their constellations, including orbital parameters and the number of needed satellites. We further discuss how the initial requirements drive the architecture parameters and performance. We demonstrate that a single satellite will not meet the current needs of the environmental sensing community, rather a constellation of multiple operational satellites is required for desirable worldwide land management missions.
Development activities for interferometer-based hyperspectral sounder instrument
Philippe Giaccari, Frederic J. Grandmont, Jacques G. Giroux, et al.
A development program was conducted to further improve the technology readiness level of the Generic Flight Interferometer (GFI), a candidate technology for the future hyperspectral sounder on MTG. Interferometer-based sounders have already demonstrated their performance and reliability in conducting advanced sounding tasks in recent missions (METOP-A, IBUKI, SCISAT). The transition from previous single-pixel (or few) to large-format array detectors offering strong hyperspectral capabilities adds technical challenges to the interferometer design. Some of the improvements required to address those challenges have already been implemented in recent deployment of hyperspectral commercial products but must be adapted to the space environment and constraints. Other improvements are dictated by mission specifics but still tend to be recurrent in recent opportunities. The GFI design intent is to regroup these innovations in a generic modular interferometer platform in order to address a variety of missions with minor modifications and hence lower development costs and risks.
RapidEye product quality assessment
Keith Beckett, Chris Rampersad, Rony Putih, et al.
Geometric and radiometric product quality are critical to enable the use of remotely sensed imagery [1,2]. Over a period of nine months following the launch, the constellation of five RapidEye satellites underwent an iterative process of commissioning, calibration and product quality assessment. This paper describes the post-launch calibration techniques used to characterize the payloads, summarizes the calibration results, and documents the product quality achieved. It illustrates how ground-based post-launch calibration techniques were successfully used to mount a geometric and radiometric calibration campaign consistent with a small-sat satellite mission, to produce high quality imagery products.
Novel miniaturized hyperspectral sensor for UAV and space applications
Heikki Saari, Ville-Veikko Aallos, Altti Akujärvi, et al.
In many hyperspectral applications it is beneficial to produce 2D spatial images with a single exposure at a few selected wavelength bands instead of 1D spatial and all spectral band images like in push-broom instruments. VTT has developed a new concept based on the Piezo actuated Fabry-Perot Interferometer to enable recording of 2D spatial images at the selected wavelength bands simultaneously. The sensor size is compatible with light weight UAV platforms. In our spectrometer the multiple orders of the Fabry-Perot Interferometer are used at the same time matched to the sensitivities of a multispectral RGB-type image sensor channels. We have built prototypes of the new spectrograph fitting inside of a 40 mm x 40 mm x 20 mm envelope and with a mass less than 50 g. The operational wavelength range of built prototypes can be tuned in the range 400 - 1100 nm and the spectral resolution is in the range 5 - 10 nm @ FWHM. Presently the spatial resolution is 480 x 750 pixels but it can be increased simply by changing the image sensor. The hyperspectral imager records simultaneously a 2D image of the scenery at three narrow wavelength bands determined by the selected three orders of the Fabry-Perot Interferometer which depend on the air gap between the mirrors of the Fabry-Perot Cavity. The new sensor can be applied on UAV, aircraft, and other platforms requiring small volume, mass and power consumption. The new low cost hyperspectral imager can be used also in many industrial and medical applications.
Development of a micro-satellite compatible FTS sounder for sun-occultation measurements
Philippe Giaccari, Louis M. Moreau, Jacques G. Giroux, et al.
The SciSat/ACE mission provided, and still provides, high quality and high spectral resolution measurements of the atmosphere with a FTS sounder in sun-occultation configuration. Based on the comprehensive results and models of SciSat/ACE it is foreseen that most of the desired information can also be retrieved from lower spectral resolution measurements with higher signal-to-noise ratio (SNR) and appropriate data treatment. With the Canadian Space Agency under the Space Technologies Development Program, ABB Analytical developed a small size sun-occultation sounder compatible with a micro-satellite platform that has identical throughput, spectral bandwidth and vertical resolution as ACE. The spectral resolution is decreased by a factor 25 (0.6 cm-1 instead of 0.024 cm-1 for ACE) whereas the SNR performance is highly increased with an equal factor (target of 2500 instead of 100 for ACE over most of the spectral bandwidth between 750 and 4000 cm-1).A prototype of the sun-occultation sounder was built, tested under various thermal conditions and subjected to vibrations similar to those expected at launch. An outdoor experiment was also conducted to test the instrument in sun-occultation conditions. The good behavior of the instrument indicates interesting opportunities for such small footprint sounder on a low-cost micro-satellite mission and potentially good earth coverage if several of such instruments are used in coordination. Depending on the scientific needs, it is possible to adapt the proposed instrument to increase the vertical resolution and/or to extend the measurements on lower altitudes due to the higher SNR performances.
Advancement of optical component control for an imaging Fabry-Perot interferometer
Allen M. Larar, William B. Cook, Michael A. Flood, et al.
Risk mitigation activities associated with a prototype imaging Fabry-Perot Interferometer (FPI) system are continuing at the NASA Langley Research Center. The system concept and technology center about enabling and improving future space-based atmospheric composition missions, with a current focus on observing tropospheric ozone around 9.6 micron, while having applicability toward measurement in different spectral regions and other applications. Recent activities have focused on improving an optical element control subsystem to enable precise and accurate positioning and control of etalon plates; this is needed to provide high system spectral fidelity critical for enabling the required ability to spectrally-resolve atmospheric line structure. The latest results pertaining to methodology enhancements, system implementation, and laboratory characterization testing are discussed.
Missions and Sensing II
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An uncooled mid wave and thermal infrared payload for fire monitoring
The Platform for the Observation of the Earth and for in-orbit Technology Experiments (POETE) mission concept has been developed to help overcome the scientific and socio-economic issues associated with forest fires. The proposed mission is based on a series of two highly autonomous and agile microsatellites, allowing for 3 to 7 visits per day. Each satellite payload includs a VIS-NIR instrument and a MWIR-TIR instrument. The two instruments combined provide for 6 spectral channels spanning from the visible to the thermal infrared for fire monitoring, retrieval of quantitative fire parameters (such as effective fire temperature, area and radiative energy release), and land surface temperature measurement. The MWIR-TIR instrument concept is a pushbroom scanner filter radiometer with on-board radiometric calibration capabilities. Its all-reflective three-mirror input optics delivers a 400-m GSD at an altitude of 700 km, relaying the scene signal to detectors based on INO's microbolometer technology for detection in four spectral channels centered at 3.8 μm, 8.8 μm, 10.5 μm and 12.0 μm. This paper presents an overview of the key mission requirements and derived sensor level requirements. A description of the conceptual design of the MWIR-TIR payload of POETE is given along with estimates of key performance parameters.
The OMPS Limb Profiler instrument: An alternative data analysis and retrieval algorithm
Didier F. Rault, Jerry Lumpe, Thomas Eden, et al.
An alternative algorithm is being analyzed to retrieve ozone and aerosol vertical distribution information from the OMPS/LP sensor which will be manifested on the upcoming NPOESS Preparatory Project (NPP) platform in early 2011. The algorithm relies on the optimal estimation method to infer ozone density and aerosol extinction directly from the radiance measurements made by the ensemble of CCD array pixels. The fundamentals of the technique are reviewed and the advantages of the method with respect to the mainstream retrieval algorithm are discussed. Sample results are given to illustrate the performance of the new method.
Applications of Global Earth Observations in Addressing Societal Benefits
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Triana II: a new constellation of operational earth remote sensing satellites
Douglas B. Helmuth, Raymond M. Bell, David A. Bennett, et al.
Understanding the earth's climate and the how it supports life is essential to government policy makers. A new constellation of operational earth remote sensing satellites (Triana II) is required to provide data to develop this understanding. Comparison of several spacecraft, sensors systems, orbits, and constellations is described and one recommended that will support many of the policy decisions facing governments around the world over the next critical decades.
Treaty monitoring from space: satellite imagery analysis for verifying treaty compliance
Earth observation generally represents a key source of information for the different national and international bodies involved in the implementation of international agreements. If the area of interest is not accessible, remote sensing sensors represent one of the few opportunities to gather almost realtime data over the area. Taking into consideration recent developments in satellite sensor technologies and software solutions, the given paper discusses some challenges with regard to both technical and political issues.
Comprehensive evaluation of eco-tourism resources in Hangzhou based on GIS
By using analytical hierarchy process (AHP) and Fuzzy method, representative evaluation factors in the aspects of tourism resources quantity, environmental quantity, tourism conditions, and tourism functions were chosen to build up a comprehensive quantitative evaluation model to evaluate the eco-tourism resources of Hangzhou region based on GIS. The results showed that in Hangzhou region, the natural eco-tourism re-sources were superior to the humanity resources. In the spatial distribution, eco-tourism resources in Hangzhou present circle shape, and it is not balance. Based on the above analyses, it gives the initial development direction of resource sub area suiting to eco-tourism resources in Hangzhou.
Poster Session
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Structure optimization of coated LPFG based on dual-peak resonance
A dual-peak resonance in coated long-period fiber grating (LPFG) is presented in this paper. By resolving the characteristic equation of the coated LPFG, the dual peak resonant wavelengths are determined based on rigorous coupled mode theory. The relationships between the dual peak resonant wavelengths and grating period and the mode ordinal are studied. The results show that the dual resonance appears in higher cladding mode, and the higher the cladding mode ordinal is, the smaller the related grating period required to couple with core mode is. Further, the influence of film optical parameters (the film thickness h3 and the refractive index n3) on the intervals of dual resonant wavelengths, as well as the attenuation peak of transmission spectra, are analyzed whether the optical dispersion is under consideration or not. The transmittance spectra show the dual resonant peaks shift in the opposite direction with the variation of the film refractive index. This can be used to construct a refractive index sensor, in which the films sensitive to the surrounding gases are coated on the cladding of the fiber grating region, and the intervals of dual peak resonant wavelengths change with the film refractive index. By using optimization method, the optimal film optical parameters and the grating structure parameters are obtained. Data simulation shows that the resolution of the refractive index of the films is predicted to be more than 10-7. The theoretic analysis provides straightforward foundation for the actual highly sensitive film sensors.
Growth and characterisation of InAsN/GaAs dilute nitride semiconductor alloys for the mid-infrared spectral range
M. de la Mare, Q. Zhuang, A. Patanè, et al.
We report the successful growth of InAsN onto GaAs substrates using nitrogen plasma source molecular beam epitaxy. We describe the spectral properties of InAsN alloys with N-content in the range 0 to 1% and photoluminescence emission in the mid-infrared spectral range. The photoluminescence emission of the sample containing 1% N reveals evidence of recombination from extended and localized states within the degenerate conduction band of InAsN. A comparison of GaAs and InAs based material shows little change in FWHM suggesting the change in substrate does not cause significant reduction in quality of the epilayers. Material grown is consistent with predictions from the band anti-crossing model (BAC model).
The Chinese environment satellite mission status and future plan
Based on China white paper "China's Space Activities in 2006", the five-year plan (2006-2010) of China earth observation plan, one of them is to form 24 hours, differential-resolution environmental system for stable operation, step by step. In this paper, the status of Chinese environment satellite mission is introduced, including meteorological satellite series, ocean satellite series and disaster satellite series. The update properties of meteorological polar satellite FY-1D, FY-3A, and geostationary satellite FY-2C and FY-2D and ocean satellite of HY-1B as well as HJ constellation of disaster small satellites, which are in orbits for operation, will described in detail. The plan of satellite and their main payloads are discussed. There are three kinds of satellite missions for environmental monitoring in China before 2020, including meteorological satellites (10 satellites), ocean observation satellites (13 satellites) and disaster monitoring satellite constellation (8 satellites). For meteorological satellite series, following FY-2D, FY-2E/F/G are planed to be launched every 2 years from 2010. Following the FY-3A, the FY-3B will be launched in 2010 which are experimental phase). The FY-3C/D/E...(operational phase) are planed, total 9 satellites which will be launched every 2 years from 2013. FY-4 is proposed to have two separate series that are the optics remote sensing series and microwave remote sensing series. For rapid response to national marine environmental protection, development of marine resources, coastal zones survey, management of marine resources, polar study and research etc, China plans to launch HY-1C/D, HY-1E/F and HY-1G/H every two years from 2011, and the HY-2 A/B/C/D and HY-3A/B and CFOSAT are planed to launch. China plans to launch disaster monitoring satellite constellation consisted of two optical satellites and one SAR satellite in coming year, called the "2+1" project, and also another 4 optical satellites and 4 SAR satellites near future ("4+4"). The paper shows that China pays very attention to development of satellites for benefit environment monitoring.