Global Change Observation Mission (GCOM) is a follow on mission of ADEOS, ADEOS2 and TRMM. It is under phase A study in JAXA (Japan Aerospace Exploration Agency). GCOM is not a series of satellites but a mission and its concept is to continuously monitor geophysical parameters which are critical to understand global change phenomena, especially phenomena related to climate change. Those parameters include, but not limited to, optical thickness of aerosols and clouds, water and energy fluxes, carbon fluxes, sink and source of greenhouse gases, etc. The measurements of geophysical parameters will continue more than 15 years after the launch of ADEOS2. The first generation satellites of GCOM after ADEOS2 is now composed of 3 satellites, i.e. GOSAT, GCOM-B1, and GPM core satellite. The target of GOSAT is to monitor tropospheric greenhouse gases and clarify sources and sinks of these gases with the aid of atmospheric inverse models. ADEOSΠwas launched on Dec., 2002. However, after about 10 months operation, it has lost most of its power due to the solar paddle failure. The exact cause of the accident is not apparent at this time, JAXA is now considering to launch a satellite as a substitute of ADEOSΠ. Up to now, candidate sensors on board this satellite is 3, i.e. GLI follow on, AMSR follow on and SeaWinds follow on. Further, ADEOSΠ F/O will be dividedd into two satellites, i.e. GCOM-C which will carry GLI F/O and GCOM-W which will carry AMSR F/O and SeaWinds F/O. The GLI F/O will be rather different from GLI. The main targets of GLI F/O are atmospheric aerosols, coastal zone and land. In order measure aerosols over both ocean and land, it will have ultra violet channels, as well as polarization and bi-directional observation capability. For, coastal zone and land observation, the IFOV of GLI F/O for these targets will be around 250m. The instrument will be composed of several components. The shorter wavelength region will adopt push broom scanners, while long wave region will use a conventional whisk broom scanner. AMSR F/O will be very similar to AMSR on ADEOSΠ and AMSR-E on EOS-Aqua. SeaWinds F/O will be also similar to SeaWinds on ADEOSΠ with some modifications. There are two options on the orbit. One is the same to that of ADEOSΠ, i.e. around 800km altitude. Another is a higher orbit to allow faster turn around. The target launch date is fiscal 2008. JAXA has other satellite series, starting from MOS-1 to JERS-1. The next satellite to follow the JERS-1 is ALOS (Advanced Land Observing Satellite), which will be launched in 2005. The mission of ALOS is to provide sufficient data, which enable to generate 1 to 25,000 scale base maps all over the world.

This paper presents an overview of the Advanced Land Observing Satellite (ALOS) and its research activities, which are carried out at the Earth Observation Research and Application Center (EORC) of the Japan Aerospace Exploration Agency (JAXA). The mission objectives of ALOS include cartography, regional observation, and disaster monitoring etc. ALOS has three mission instruments, the PRISM, AVNIR-2, and PALSAR, to achieve these objectives. Our research activities can be categorized into two main parts of the ALOS mission: calibration and validation, and application and science. We are presently developing calibration and validation tools for each sensor, evaluating the pre-flight test data acquired on the ground, establishing test sites and reference facilities, and considering mission operation plans to observe the test sites effectively. The application and scientific results will demonstrate the ALOS data utilization capability. We define the digital elevation model (DEM), ortho-rectified images for each sensor, and the surface deformation map as high-level and research products. We describe here our research and scientific activities, particularly calibration and validation, to improve the absolute accuracy and image quality of the products and we provide some examples of data utilization.

The data analyses of the ADEOS-II (Midori-II) GLI data have started. The optical and microphysical properties of warm water and cold ice clouds were retrieved by use of originally developed GLI data analysis algorithms. On the one-month mean results of warm water cloud in April 2003, very thick cloud optical thickness appeared in the east coast of the North America, the East Europe, and the South-East Asia. The moderately optically thick area spread over the Atlantic Ocean and West to Middle Pacific oceans. The effective radius was smaller on the continents and coastal area than ocean area. Especially, the South-East Asia to the middle pacific area where often covered with aerosols coming from continent in April, is the region of the smaller cloud effective particles. For the cirrus clouds, the smaller effective radii and larger effective radii can be obtained in low-to-mid and mid-to-high latitude area, respectively. Very low cloud top temperatures around 210K were often observed in the tropics. Warmer cloud top temperatures ranging from 220 to 240K were widely seen both over continental and oceanic area in mid-to-high latitude area.

ASTER instrument on Terra spacecraft is operating over 4 years since early 2000. The total number of acquired data exceeds 800 thousand scenes. The radiometric coefficients are frequently updated to compensate the degradation. The geometric performance is kept in good accuracy since the initial normal operation stage. The performance for radiometric, geometric and stereo capabilities will be comprehensively presented.

Space-borne optical remote sensor, ASTER instrument, has VNIR, SWIR and TIR bands and stereo capability. The author had made a preliminary study for the Ethiopian Rift Valley by using only TIR data by his previous paper[11]. In this study, more comprehensive study for geologic interpretation is performed by using all the VNIR, SWIR and TIR, and the topographic information extracted from along track stereo pair data.

The concept study of new multi spectral imager has been showed. Multi spectral imager is the basic sensor for Earth remote sensing. The result of Global Imager (GLI) of Advanced Earth Observation Satellite -2 (ADEOS-2) showed us the various change of climate system. However, according to the progress of climate system change study, the reconsideration of observation channels is necessary. First, we studied the requirements of the next generation imager on the basis of GLI design considering the less observed parameters of the climate change. Then we found the necessity of the parameters related the human activities. Several parameters of each area, i.e., atmosphere, ocean, land, cryosphere, are selected. For the atmosphere, aerosol over land is emphasized. For the ocean, coastal change observation is proposed. For the land, advanced vegetation index is proposed. For the cryosphere, impurity of snow is emphasized. For the observation purposes, the proposed imager requirements are including the multi-angle polarization observation. And the resolution requirements of most channels are changed from 1 km to 250m. As the result of preliminary engineering study, the imager consists of a push broom imager for Visible and Near Infrared (VNIR) region, and a whisk broom imager for Shortwave Infrared (SWIR) and Thermal Infrared (TIR) region. Among the all channels, two channels, center wavelength 678 nm and 865 nm, are defined as multi-angle polarization observation channels. Each channel has fore, nadir, aft angles, also three polarization angles. The satellite orbit is about 800 km height sun-synchronous polar orbit to cover global area. The new sensor was named Second generation of Global Imager (SGLI). We are proposing to launch SGLI around 2010 on a satellite of Global Change Observation Mission (GCOM).

The European Space Agency is pursuing the development of innovative Earth Observation missions to foster better scientific understanding of the system Earth and to respond to the requirements of the operational users. Four Earth Explorer missions (CRYOSAT, GOCE, SMOS, AEOLUS) are under development for launch between 2005 and 2008, to provide new critical information on ocean circulation, the Earth gravity field, the cryosphere, ocean salinity and soil moisture and to demonstrate the feasibility of the measurement of tropospheric wind fields. Following recent phase A studies, the SWARM constellation mission, aimed at the precise mapping of the Earth's magnetic field, has been selected for implementation. A further Explorer mission addressing aerosol-radiation-cloud interactions (EarthCARE) or the carbon cycle (SPECTRA) will be selected before the end of 2004. Application-oriented missions of the Earth Watch class are vigorously continuing with the METEOSAT series of geostationary meteorological satellites, the preliminary studies of the next-generation METEOSAT spacecraft and the preparation of the launch of the EPS/METOP series. Preparatory activities are starting for the series of operational missions, to provide data and services for Earth monitoring, in the frame of the GMES programme.

The first of the new generation of Meteosat satellites, known as Meteosat Second Generation (MSG), was launched in August 2002. From its geostationary orbit, the satellite's radiometer, the spinning enhanced visible and infrared imager (SEVIRI), observes the full disk of the Earth with an unprecedented repeat cycle of 15 minutes in 12 spectral channels, having a sampling distance of three kilometres at nadir (1 km for the high resolution channel). For comparison, the first-generation Meteosat satellite covers only three spectral channels and has an imaging repeat cycle of 30 minutes, with a sampling distance between 2.5 and 5 km. MSG offers a wealth of new observational capabilities that could benefit weather forecasting and support severe weather warnings. Significant indirect benefits will come through improved weather forecasts that predict e.g. wind fields more accurately. With the beginning of MSG's operational phase on 29 January 2004, the satellite was renamed to Meteosat-8. The Meteosat-8 operational system also includes a suite of meteorological data which are extracted from the multi-channel image information, as e.g. winds, cloud analysis, atmospheric humidity and atmospheric instability over the entire field of view. This paper presents a general overview over the Meteosat-8 imagery and will especially focus on the meteorological parameters - including the underlying algorithms - that are extracted at EUMETSAT.

The operational deployment of MSG-1 at the beginning of 2004, the first of a series of four Meteosat Second Generation (MSG) satellites, marks the start of a new era in Europe for the meteorological observations from the geostationary orbit. The new system shall be the backbone of the European operational meteorological services up to at least 2015. The time required for the definition and the development of new space systems as well as the approval process of such complex programs implies anyhow to plan well ahead for the future missions. EUMETSAT have initiated in 2001, with ESA support, a User Consultation Process aiming at preparing for a future operational geostationary meteorological satellite system in the post-MSG era, named Meteosat Third Generation (MTG). The first phase of the User Consultation Process was 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 intermediate results of this first phase were presented to and discussed with the user community at the first Post-MSG User Consultation Workshop convened by EUMETSAT in November 2001 and further consolidated with the support of ESA in the area of potential observation techniques and sensor concepts via dedicated studies conducted in the 2003/2004 time frame. The following missions have been analysed and preliminary concepts studied: -High Resolution Fast Imagery Mission (successor to MSG SEVIRI HRV mission) -Full Disk High Spectral Resolution Imagery Mission (successor to the mission of other MSG-SEVIRI channels) -Lightning Imagery Mission -IR Sounding Mission -UV-VIS-NIR-SWIR Sounding Mission In March 2003, ESA and EUMETSAT derived technical requirements applicable to the MTG mission study where preliminary instrument concepts were investigated allowing in the same time to consolidate the technical requirements for the overall system study. This paper provides an overview of the outcome of the MTG observation techniques and sensor concept studies conducted in 2003-2004. It namely focuses onto the Imaging and Sounding Missions, highlights the resulting instrument concepts and introduces the study steps towards the implementation of the MTG development programme.

Due for launch in late 2007, the Atmospheric Dynamics Mission (ADM-Aeolus) has been selected as the second Earth Explorer Core Missions within ESA Living Planet Programme. Its payload aims at providing measurements of atmospheric wind profiles with global coverage. The key elecment of ADM-Aeolus is the Atmospheric LAser Doppler Lidar INstrument (ALADIN), a Direct Detection Doppler Lidar in the ultra-violet spectral region operating with aerosol and molecular backscatter signals in parallel. The ALADIN instrument belongs to a completely new class of earth-observation payloads with limited power requirements and high reliability over a three-year lifetime. It will be the first European Lidar in space. Technological challenges are addressed in an early stage by a pre-development programme that consists of designing, manufacturing and testing a functional representative model of the receiver of ALADIN (the Pre-Development Model, PDM), and a breadboard of the transmitter. The pre-development programme is being established to validate the technologies used in the ALADIN design, evaluate the flight-worthiness of its major subsystems and verify the instrument overall performances. The purpose of this paper is to present the main achievements of the pre-development programme: environmental tests on the Pre-Development Model (thermal-vacuum and mechanical tests), development of the laser breadboards and assessment programme of the laser diodes.

Six candidate Earth Explorer (satellite) missions were undergoing phase A industrial studies and science consolidation from 2002 to early 2004. They included 3 'Core' missions (EarthCARE, SPECTRA and WALES) and 3 'Opportunity' missions (ACE+, EGPM, SWARM). Three of the candidate missions carry microwave payloads for atmospheric sensing. In April 2004, a selection workshop was held, and recommendations for implementation (phases B, C, D) were made by the Earth Sciences Advisory Committee (ESAC) and an implementation decision was taken by the Programme Board on Earth Observation (PB-EO) in May. SWARM, a magnetometry mission, was selected for full implementation as a 5th Explorer mission. The decision for the 6th Explorer mission was postponed to Nov. 2004 between EarthCARE and SPECTRA candidates, pending on the confirmation by JAXA on its contribution to EarthCARE and a re-examination by ESA. EGPM was recommended for implementation under the GMES, a new ESA programme of operational missions. In this paper, EarthCARE and EGPM are described with a particular emphasis on the microwave payloads.

TerraSAR-L is the new imaging radar mission of the European Space Agency, with Astrium Ltd. acting as Prime Contractor. The platform, based on the novel Snapdragon concept, is built around the active phase array antenna of the L-band Synthetic Aperture Radar (L-SAR). Specification of the L-SAR has been guided by careful analysis of the product requirements resulting in a robust baseline design with appropriate margins. Besides providing commercial geo-information products, TerraSAR-L will contribute to the Global Monitoring for Environment and Security (GMES) initiative and serve the scientific user community. Major application areas are: Kyoto inventory and wetland monitoring, solid earth science including seismic and volcanic activity as well as land slides and subsidence, land cover classification in different levels of detail and marine applications. The TerraSAR-L operations strategy is based on a long-term systematic and repetitive acquisition scenario to ensure consistent data archives and to maximise the exploitation of this very powerful SAR system.

This paper outlines the development status of an L-band SAR antenna demonstrator undertaken by an industrial consortium under contract to ESA. Its aim is to verify the technology and the satisfactory performance of the SAR active antenna in advance of the development of the full L-band SAR instrument.

Future planetary missions will require advanced, smart, low resource payloads and satellites to enable the exploration of our solar system in a more frequent, timely and multi-mission manner. A viable route towards low resource science instrumentation is the concept of Highly Integrated Payload Suites (HIPS), which was introduced during the re-assessment of the payload of the BepiColombo (BC) Mercury Planetary Orbiter (MPO). Considerable mass and power savings were demonstrated throughout the instrumentation by improved definition of the instrument design, a higher level of integration, and identification of resource drivers. The higher integration and associated synergy effects permitted optimisation of the payload performance at minimum investment while still meeting the demanding science requirements. For the specific example of the BepiColombo MPO, the mass reduction by designing the instruments towards a Highly Integrated Payload Suite was found to be about 60%. This has endorsed the acceptance of a number of additional instruments as core payload of the BC MPO thereby enhancing the scientific return. This promising strategic approach and concept is now applied to a set of planetary mission studies for future exploration of the solar system. Innovative technologies, miniaturised electronics and advanced remote sensing technologies are the baseline for a generic approach to payload integration, which is here investigated also in the context of largely differing mission requirements. A review of the approach and the implications to the generic concept as found from the applications to the mission studies are presented.

NASA's Science Mission Directorate, working with its domestic and international partners, provides accurate, objective scientific data and analysis to advance our understanding of Earth system processes. Learning more about these processes will enable improved prediction capability for climate, weather, and natural hazards. Earth interactions occur on a continuum of spatial and temporal scales ranging from short-term weather to long-term climate, and from local and regional to global. Quantitatively describing these changes means precisely measuring from space scores of biological and geophysical parameters globally. New missions that SMD will launch in the coming decade will complement the first series of the Earth Observing System. These next generation systematic measurement missions are being planned to extend or enhance the record of science-quality data necessary for understanding and predicting global change. These missions include the NPOESS Preparatory Project, Ocean Surface Topography Mission, Global Precipitation Measurement, Landsat Data Continuity Mission, and an aerosol polarimetry mission called Glory. New small explorer missions will make first of a kind Earth observations. The Orbiting Carbon Observatory will measure sources and sinks of carbon to help the Nation and the world formulate effective strategies to constrain the amount of this greenhouse gas in the atmosphere. Aquarius will measure ocean surface salinity which is key to ocean circulation in the North Atlantic that produces the current era's mild climate in northern Europe. HYDROS will measure soil moisture globally. Soil moisture is critical to agriculture and to managing fresh water resources. NASA continues to design, develop and launch the Nation's civilian operational environmental satellites, in both polar and geostationary orbits, by agreement with the National Oceanic and Atmospheric Administration (NOAA). NASA plans to develop an advanced atmospheric sounder, GIFTS, for geostationary orbit to facilitate continuous measurements of weather-related phenomena, improve "nowcasting" of extreme weather events, and measure important atmospheric gases. NASA is currently developing with its partners the National Polar-orbiting Operational Environmental Satellite System (NPOESS) and the next-generation geostationary system, GOES-R. Future missions will migrate today's capabilities in low Earth orbit to higher orbits such as L1 and L2 to enable more continuous monitoring of changes in the Earth system with a smaller number of satellites.

The next-generation National Oceanic and Atmospheric Administration (NOAA) Geostationary Operational Environmental Satellite (GOES-R series) is currently being developed by NOAA in partnership with the National Aeronautics and Space Administration (NASA). The GOES-R series satellites represents a significant improvement in spatial, temporal, and spectral observations (several orders of magnitude) over the capabilities of the currently operational GOES-I/M series and GOES-N series satellite to be launched at the end of 2004. The GOES-R series will incorporate technically advanced "third-generation" instruments and spacecraft enhancements to meet evolving observational requirements of forecasting for the era 2012-2025. The GOES-R instrument complement being developed includes an Advanced Baseline Imager (ABI), a Hyperspectral Environmental Suite (HES), a GEO Lightning Mapper (GLM), a Solar Imaging Suite (SIS) and a Space Environment In-Situ Suite (SEISS). Also, candidates for a number of GOES-R Pre-Planned Product Improvements (P3Is) includes a Geo Microwave Sounder, a Coronagraph, a Hyperspectral Imager, and a Solar Irradiance Sensor. Currently, the GOES-R space segment architecture is being evaluated as part of a GOES-R system End-to-End Architecture Study. The GOES-R notional baseline architecture is a constellation of two satellites (A-sat and B-sat) each nominally located at 75 degrees West longitude and at 135 degrees West longitude at geostationary altitude, 0 degrees inclination. The primary mission of the A-sat is to provide imaging from the ABI. The A-sat will also contain the SIS and the GLM. The primary mission of the B-sat is to provide sounding of the hemispherical disk of the earth from the HES. The B-sat also contains the SEISS. Both satellites have mesoscale capabilities for severe weather sounding or imaging. This paper overviews the GOES-R Space Segment development including satellite constellation trade-off, improvements and differences between the current and future instrument and spacecraft capabilities, and technology infusion.

The Geostationary Operational Environmental Satellite R (GOES-R) Series is the planned next generation of operational weather satellites for the United State’s National Oceanic and Atmospheric Administration (NOAA). The first launch of the GOES-R series is planned for 2012. The GOES-R Series satellites and instruments are being developed by the National Aeronautics and Space Administration (NASA). One of the key instruments on the GOES-R Series is the Advanced Baseline Imager (ABI). The ABI is a multi-channel, visible through infrared, passive imaging radiometer. The ABI will provide moderate spatial and spectral resolution at high temporal and radiometric resolution to accurately monitor rapidly changing weather. The ABI will provide sixteen spectral channels compared to five channels on the current GOES I/P Series Imager. This increase will allow more comprehensive monitoring of atmospheric conditions such as aerosol concentration, cirrus cloud location, and cloud properties. In addition, ABI will provide data products with a spatial resolution of at least half the current imager, down to 0.5 Km in the visible band. With its high temporal coverage, full disk every 5 minutes, and ability to continue operations around local midnight, ABI will provide continuous and timely monitoring of weather. This is further augmented by ABI's ability to revisit a specified 1000 Kilometer region every 30 seconds to track severe weather. This paper discusses the anticipated performance characteristics of the ABI sensor. The key data products achievable from the ABI are also discussed.

The Hyperspectral Environmental Suite (HES) instrument is currently under development by the NASA GOES-R Project team within the framework of the GOES Program to fulfill the future needs and requirements of the National Environmental Satellite, Data, and Information Service (NESDIS) Office. As part of the GOES-R instrument complement, HES will provide measurements of the traditional temperature and water vapor vertical profiles with higher accuracy and vertical resolution than obtained through current sounder technologies. HES will provide measurements of the properties of the shelf and coastal waters and back up imaging (at in-situ resolution) for the GOES-R Advanced Baseline Imager (ABI). The HES team is forging the future of remote environmental monitoring with the development of an operational instrument with high temporal, spatial and spectral-resolution and broad hemispheric coverage. The HES development vision includes threshold and goal requirements that encompass potential system solutions. The HES team has defined tasks for the instrument(s) that include a threshold functional complement of Disk Sounding (DS), Severe Weather/Mesoscale Sounding (SW/M), and Shelf and Coastal Waters imaging (CW) and a goal functional complement of Open Ocean (OO) imaging, and back up imaging (at in-situ resolution) for the GOES-R Advanced Baseline Imager (ABI). To achieve the best-value procurement, the GOES-R Project has base-lined a two-phase procurement approach to the HES design and development; a Formulation/study phase and an instrument Implementation phase. During Formulation, currently slated for the FY04-05 timeframe, the developing team(s) will perform Systems Requirements Analysis and evaluation, System Trade and Requirements Baseline Studies, Risk Assessment and Mitigation Strategy and complete a Preliminary Conceptual Design of the HES instrument. The results of the formulation phase will be leveraged to achieve an effective and efficient system solution during the Implementation Phase scheduled to begin FY05 for a resultant FY12 launch. The magnitude of complexity of the HES development requires an appreciation of the technologies required to achieve the functional objectives. To this end, the GOES-R project team is making available all NASA developed technologies to potential HES vendors, including, the NASA New Millennium Program’s (NMP) Earth Observing-3, Geostationary Imaging Fourier Transform Spectrometer (GIFTS) instrument developed technologies, as applicable. It is anticipated that the instrument(s) meeting the HES requirements will be either a dispersive spectrometer or an interferometric spectrometer or perhaps a combination. No instrument configuration is preferred or favored by the Government. This paper outlines the HES development plan; including an overview of current requirements, existing partnerships and the GOES-R project methodologies to achieve the advanced functional objectives of the GOES Program partnership.

There are several microwave instruments in low Earth orbit (LEO) that are used for atmospheric temperature and humidity sounding by themselves and in conjunction with companion IR sounders. These instruments have achieved a certain degree of maturity and are undergoing a redesign to minimize their size, mass, and power requirements from the previous generation instruments. An example of these instruments is the AMSU-A series, now flying on POES and Aqua spacecraft, with the IR sounders HIRS3 and AIRS respectively. These older microwave instruments are going to be replaced by the ATMS instruments that will fly on NPP and NPOESS satellites with the CrIS IR sounder. A number of enabling technologies acquired from the ATMS instrument hardware design and data processing are directly applicable to performing similar microwave sounding on a geostationary platform. Because these technologies are already in place, they are readily available for the development of a geostationary orbit (GEO) microwave instrument, thereby avoiding costly technology development and minimizing the risk of not achieving the scientific requirements. In fact, the MMIC microwave components that were developed by ATMS for size and volume reduction are directly applicable to a GEO microwave sounder. The benefits of microwave sounders are well known. They penetrate non-precipitating cloud cover and allow for accurate soundings obtained with a collocated high spectral resolution IR sounder in up to 80% cloud cover. The key advantages of a microwave instrument in GEO will be its ability to provide high temporal resolution and uniform spatial resolution, and it will expand the utility of a collocated advanced IR sounder to cases in which partial cloud cover exists. A footprint in the order of 100 km by 100 km resolution with hemispherical coverage within one hour can be easily achieved for sounding channels in the 50 to 57 GHz range. A GEO microwave sounder will also allow mesoscale sampling of select regions.

Global Precipitation Measurement (GPM) is a global space endeavor conceived by the US and Japan that has sparked global interest. Building upon the success of the Tropical Rainfall Measuring Mission (TRMM), it will initiate the measurement of global precipitation, a key climate factor. Its science objectives are to improve ongoing efforts to predict climate by providing near-global measurement of precipitation, its distribution, and physical processes; to improve the accuracy of weather and precipitation forecasts through more accurate measurement of rain rates and latent heating; and to provide more frequent and complete sampling of the Earth's precipitation. It has received endorsements from the World Climate Research Programme, the World Meteorological Organization, and the Committee on Earth Observation Satellites. GPM is envisioned to consist of a core spacecraft to measure precipitation structure and to provide a calibration standard for the constellation spacecraft, an international constellation of spacecraft to provide frequent precipitation measurements on a global basis, calibration/validation sites distributed globally with a broad array of precipitation-measuring instrumentation, and a global precipitation data system to produce and distribute global rain maps and climate research products. The National Aeronautics and Space Administration (NASA) plans to provide the core spacecraft, a constellation spacecraft and its launch, microwave radiometers, the precipitation processing system, the mission operations system, and an array of ground calibration and validation sites. The Japan Aerospace Exploration Agency (JAXA) plans to contribute the radar for and launch of the core spacecraft. The European Space Agency (ESA) has studied a European constellation satellite contribution. India and France have expressed their interest in participating through the Megha-Tropiques project. South Korea has proposed the contribution of regional ground validation sites. Other nations are also expected to play major a role in GPM. GPM is now in formulation phase and is one of the highest priority new Earth science missions for which NASA seeks final approval. GPM launches are targeted to begin in 2010.

The application of hyper spectral radiometric data to climate research requires very high absolute radiometric accuracy and stability. We use cloud-free tropical ocean data from the Atmospheric InfraRed Sounder (AIRS) Calibration Data Subset (ADCS) to show that the radiometric precision and stability required for climate applications has been achieved. The sea surface skin temperatures derived from the AIRS 2616cm-1 super window channel are stable relative to the RTG.SST at the better than 8 mK/year level, and the spectral calibration is stable at the 1 ppm/year level. The excellent stability and accuracy are the result of the implementation of AIRS as a grating array spectrometer, which is cooled and stabilized within 10 mK at 155 K. Analysis of daily measurements of the temperature gradient between the surface and 7 km altitude show that the AIRS Calibration Data Subset has applications which extend its original intent for calibration support to climate research. The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua satellite was launched into polar orbit in May 2002. AIRS covers the spectral region from 640 to 2700 cm-1 with 2378 independent channels and represents the first of a new generation of hyper spectral resolution sounders in support of global sounding data for weather forecasting and climate research.

A new class of low-cost mid-wave infrared (MWIR) Earth observation (EO) data will become available with the flight of miniature MWIR EO instruments in micro-satellite constellations. Due to the frequent ground repeat times inherent in constellations, this data set would provide a unique alternative for those wishing to analyse trends or rapidly detect anomalous changes in the MWIR characteristics of the Earth's surface (e.g. fire detection) or atmosphere. To date, the MWIR imagers have been based on highly responsive cooled detector technology, which traditionally has been the only real option for collecting useful data in this waveband from space. However, state-of-the art microbolometers, adapted from their original design for operation in the LWIR, are thought to be a potential alternative for low-cost MWIR constellations. Following the laboratory evaluation of a modified microbolometer arrays in the MWIR, a low-mass instrument concept was designed and evaluated for a variety of candidate MWIR mission areas. If implemented, the imager concept would complement a larger imaging suite (visible, near IR, and long-wave IR) on a sub-100kg Surrey Space Technology Ltd. (SSTL) micro-satellite and open up several new potential mission areas for the SSTL-engineered Disaster Monitoring Constellation.

An innovative approach that enables greatly increased return from earth and planetary science remote sensing missions is described. Our concept, called Multiple Instrument Distributed Aperture Sensor (MIDAS), provides a large-aperture, wide-field, diffraction-limited telescope at a fraction of the cost, mass and volume of conventional space telescopes, by integrating advanced optical interferometry technologies. All optical assemblies are integrated into MIDAS as the primary remote sensing science payload, thereby reducing the cost, resources, complexity, integration and risks of a set of back-end science instruments (SI's) tailored to a specific mission, such as advanced SI's now in development for earth and planetary remote sensing missions. MIDAS interfaces to multiple SI's for redundancy and to enable synchronized concurrent science investigations, such as with multiple highly sensitive spectrometers. Passive imaging modes with MIDAS enable remote sensing at diffraction-limited resolution sequentially by each science instrument, as well as in somewhat lower resolution by multiple science instruments acting concurrently on the image, such as in different wavebands. Our MIDAS concept inherently provides nanometer-resolution hyperspectral passive imaging without the need for any moving parts in the science instruments. In its active remote sensing modes using an integrated laser source, MIDAS enables LIDAR, vibrometry, illumination, various active laser spectroscopies such as ablative, breakdown or time-resolved spectroscopy. The MIDAS optical design also provides high-resolution imaging for long dwell times at high altitudes, thereby enabling real-time, wide-area remote sensing of dynamic changes in planet surface processes.

Three series of marine remote sensing satellite are plan in China for future. They are ocean color satellite series HY-1, dynamic satellite series HY-2 and comprehensive satellite series HY-3. The series HY-1 is designed to measure the ocean color and temperature environment with the visible and infrared sensor, such as COCTS and high spectrum resolution scanner. The series HY-2 is focused on the marine dynamic environment such as wind, wave and current by the altimeter, scatter meter, radiometer and Synthetic Aperture Radar (SAR). The series HY-3 is planned to have comprehensive function what combines the series HY-1 and HY-2 using both of visible/infrared and microwave sensors. In this paper, first, the development of Chinese ocean remote sensing satellite in last ten years is introduced. Then the future generation of ocean remote sensing is described. Finally, the technique of data processing and application are suggested for the future ocean remote sensing in China.

One method to assess in-flight Modulation Transfer Function (MTF) relies on couples of images of the same landscape acquired with two spatial resolutions. 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. Last studies of this method have given the opportunity to correct the results from the aliasing effect usually disturbing the measurements around Nyquist frequency. This paper begins with a brief recall of the method including the aliasing correction. The next step presents the data to be processed. The method requires couples of images. In the SPOT5 case, several kinds of couples are constituted: (HX/THR), (THR/airborne image) and (HRS/THR). The presentation of the corresponding results naturally follows. Last part of the paper consists in a comparison with SPOT5 measurements given by other methods: least square method, edge method and point source method for the THR.

Optical remote sensing images are usually acquired according to the classical pushbroom principle. A linear array of CCD detectors, placed in the focal plane of the telescope, acquires a scanline over an integration time. The satellite's motion along its orbit, which is perpendicular to the linear array, ensures acquisition of successive lines. Because of inter-detector sensitivity differences, the image of a uniform landscape is striped vertically. Detector normalization aims at correcting these relative sensitivities and delivering uniform images of uniform areas. Determination of inter-detector coefficients requires observation of one uniform landscape, provided that each detector behaves linearly. High resolution optical satellites like the future French PLEIADES-HR have to face a lack of signal, which moves the useful signal range towards the non-linear part of the detector response. For such designs, normalization has to be run with a non-linear model : this is a cost-effective way to improve image quality at low radiances and relax detector sorting. Regarding in-flight operations, non-linear parameters identification requires observation of several uniform landscapes and may be actually very difficult to run, because of the uniformity constraint. An efficient way to bypass the quest of uniformity is to use the satellite agility in order to align the ground projection of the scanline on the ground velocity. This weird viewing principle allows all the detectors to view the same landscape. Thus, non-linear normalization coefficients can be computed by a histogram matching method. The goal of this paper is to present the Pleiades-HR non-linear normalization model, the suited steered mode and the method to compute the coefficients within Pleiades-HR context.

Since SPOT1 launch in February 1986 and until SPOT5 launch in May 2002, the methods and means to insure the best quality of the images delivered to SPOT IMAGE customers have been continuously improved and updated. The quality of the corrected images is quantified through several figures of merit, including, for radiometric quality, the Signal-to-Noise Ratio (SNR). Radiometric noise is due to two separate phenomena: -column-wise noise: it represents on-board image chain performances. -line-wise noise: normalization defects (radiometric model deviations) may lead to visible “columns” on a uniform landscape. For each image, these two noises are combined in an “image noise” that quantifies the variations of the digital numbers on a uniform landscape. Different techniques can be used to assess these different noises in-flight. For SPOT1 to SPOT4, the on-board lamp is used for both normalization and SNR assessment. For SPOT5, without lamp unit, we use images acquired over the quasi-uniform landscapes of Antarctic and Greenland for normalization. However, uniformity of these landscapes is not sufficient to accurately measure the SNR. So, a new method experimented during SPOT3 in-flight commissioning phase and operational for SPOT5 is applied. It consists in using two images of the same landscape acquired simultaneously to eliminate the landscape contribution. This paper focuses on the presentation of this new method and compares its accuracy to the other methods. Finally, a comparison between flight measurements and ground measurements before launch is given.

The paper presents a concept of a smart pushbroom imaging system with compensation of attitude instability effects. The compensation is performed by active opto-mechatronic stabilization of the focal plane image motion in a closed loop system with visual feedback on base of an auxiliary matrix image sensor and an onboard optical correlator. In this way the effects of the attitude instability, vibrations and micro shocks can be neutralized, the image quality improved and the requirements to satellite attitude stability reduced. To prove the feasibility and to estimate the effectiveness of the image motion stabilization, a performance model of the smart imaging system has been developed and a simulation experiment has been carried out. The description of the performance model and the results of the simulation experiment are also given.

The high-strength reaction-sintered silicon carbide (RS-SiC) developed and manufactured by Toshiba and NEC-Toshiba Space Systems, NT-SiC, is one of the most promising, excellent and feasible candidates for light-weighted large-diameter space-borne optics that are applied to geostationary earth observations and astronomical observations. Small NT-SiC sample mirrors were manufactured to study basic physical parameters and features, and optical performances of the material, such as the surface conditions of polished NT-SiC, the condition of inner crystal grains, the correlation between the surface roughness and polishing, scattering characteristics, absorbance of solar light and infrared emissivity, and adhesiveness of metal coating. The current state of the art of the development of the NT-SiC mirror and the feasibility of light-weighted large-diameter NT-SiC mirrors for space-borne optics are described. Although technical challenges to achieve the surface roughness that is applicable to ultraviolet mirrors still remain, the optical performance and the physical properties of the present NT-SiC show that it is one of the most excellent mirror material in optical-infrared wavelength region.

The full potential of current remote sensor technology is limited by the inability to correct biases once an exo-atmospheric remote sensor becomes operational. Even when the calibration is traced to the International System of Units, SI, and the instrument is performing within the operational envelope wherein it is calibrated, the problem exists and a Space Metrology Program is a potential solution to the problem. This paper discusses such a program, suggests a feasibility study to address the issues and recommends a plan of action. Any operational instrument has a bias and reducing the magnitude of the bias can only be accomplished when an adequately accurate standard is accessible by the instrument while the instrument is in its operational environment. Currently the radiometric flux from the sun, the moon and the stars is inadequately accurate SI to provide a standard that is consistent with the remote sensor state-of-the-art technology. The result is data that is less accurate than it could be often leading to confusing and conflicting conclusions drawn from that data. Planned remote sensors such as those required to meet future program needs (e.g. the United States National Polar-Orbiting Operational Environmental Satellite System (NPOESS) and the proposed international Global Earth Observation Program) are going to need the higher accuracy radiometric standards to maintain their accuracy once they become operational. To resolve the problem, a set of standard radiometers on the International Space Station is suggested against which other exo-atmospheric radiometric instruments can be calibrated. A feasibility study for this program is planned.

This paper reports on an investigation of radiometric calibration errors due to differences in spectral response functions between satellite sensors when attempting cross-calibration based on near-simultaneous imaging of common ground targets in analogous spectral bands. Five Earth observation sensors on three satellite platforms were included on the basis of their overpass times being within 45 minutes of each other on the same day (Landsat-7 ETM+; EO-1 ALI; Terra MODIS; Terra ASTER; Terra MISR). The simulation study encompassed spectral band difference effects (SBDE) on cross-calibration between all combinations of the sensors considered, using the Landsat solar reflective spectral domain as a framework. Scene content was simulated using ground target spectra for the calibration test sites at Railroad Valley Playa, Nevada and Niobrara Grassland, Nebraska. Results were obtained as a function of calibration test site, satellite sensor, and spectral region. Overall, in the absence of corrections for SBDE, the Railroad Valley Playa site is a "good" to "very good" ground target for cross-calibration between most but not all satellite sensors considered in most but not all spectral regions investigated. "Good" and "very good" are defined as SBDEs within +/- 3 % and +/- 1 %, respectively. Without SBDE corrections, the Niobrara test site is only "good" for cross-calibration between certain sensor combinations in some spectral regions. The paper includes recommendations for spectral data and tools that would facilitate cross-calibration between multiple satellite sensors.

The MODIS Flight Model 1 (FM1) has been in operation for more than two years since its launch onboard the NASA's Earth Observing System (EOS) Aqua spacecraft on May 4, 2002. The MODIS has 36 spectral bands: 20 reflective solar bands (RSB) with center wavelengths from 0.41 to 2.2mm and 16 thermal emissive bands (TEB) from 3.7 to 14.5mm. It provides the science community observations (data products) of the Earth's land, oceans, and atmosphere for a board range of applications. Its primary on-orbit calibration and characterization activities are performed using a solar diffuser (SD) and a solar diffuser stability monitor (SDSM) system for the RSB and a blackbody for the TEB. Another on-board calibrator (OBC) known as the spectro-radiometric calibration assembly (SRCA) is used for the instrument's spatial (TEB and RSB) and spectral (RSB only) characterization. We present in this paper the status of Aqua MODIS calibration and characterization during its first two years of on-orbit operation. Discussions will be focused on the calibration activities executed on-orbit in order to maintain and enhance the instrument's performance and the quality of its Level 1B (L1B) data products. We also provide comparisons between Aqua MODIS and Terra MODIS (launched in December, 1999), including their similarity and difference in response trending and optics degradation. Existing data and results show that Aqua MODIS bands 8 (0.412mm) and 9 (0.443mm) have much smaller degradation than Terra MODIS bands 8 and 9. The most noticeable feature shown in the RSB trending is that the mirror side differences in Aqua MODIS are extremely small and stable (<0.1%) while the Terra MODIS RSB trending has shown significant mirror side difference and wavelength dependent degradation. The overall stability of the Aqua MODIS TEB is also better than that of the Terra MODIS during their first two years of on-orbit operation.

The United States Geologic Survey (USGS) has developed a lunar irradiance model for comparison with on-orbit sattelite instruments. The comparisons are given as the percent difference of the satellite measurements from the model-generated lunar irradiances. For users of the USGS lunar model, details of the inner operation of the model are unknown. That operation is not examined here. Rather, we examine the outputs of the model. We treat the model-generated lunar irradiances as independent data sets, with each covering only a limited range of phase angles in the comparison with an individual satellite instrument. We correct the model irradiances to standard Sun-Moon and Moon-instrument distances and to fixed values for the phase and libration angles. These same corrections can be applied to the measuements by the comparison satellite instrument. For the model outputs examined here, the time trends in the corrected irradiances differ from zero change by less that 0.0014% per thousand days, and the residual scatter in the results is 0.013% (1σ). There are no apparent oscillations in the time series. At this level, the lunar model should provide an adequate reference for instruments that measure long-term climate change. The model outputs here correspond to the bands from the Sea-viewing Wide Field-of-View Sensor (SeaWiFS) instrument and to the phase angle range for the SeaWiFS lunar measurements, which is from 5° to 10°, both before and after full phase. Similar results have been obtained for model outputs corresponding to lunar measurements from the Moderate Resolution Imaging Sectroradiometer (MODIS) instruments onboard the Terra and Aqua spacecraft. This technique is applicable to other instruments that measure at wavelengths from 400 nm to 2500 nm since, in addition to the relative spectral responses of the instrument's bands, the only requirements for the model are the time and location of the instrument's lunar measurements.

Terra MODIS, also referred to as the MODIS Protoflight Model (PFM), was launched on-board the NASA's EOS Terra spacecraft on December 18, 1999. It has been in operation for more than four years and continuously providing the science community quality data sets for studies of the Earth's land, oceans, and atmosphere. It has also served as the primary source of information for the MODIS Land Rapid Response System for observing and reporting on natural disasters, and providing active fire information around the Earth. The MODIS instrument has 36 spectral bands with wavelengths ranging from 0.41mm to 14.5mm: 20 bands with wavelengths below 2.2mm are the reflective solar bands (RSB) and the other 16 bands are the thermal emissive bands (TEB). The RSB are calibrated on-orbit using a solar diffuser (SD) with the degradation of its bi-directional reflectance factor (BRF) tracked by an on-board solar diffuser stability monitor (SDSM). The calibration coefficients are updated via Look-Up Tables (LUTs) for the Level 1B code that converts the sensor's Earth view response from digital counts to calibrated reflectance and radiance. In this paper we review the MODIS RSB on-orbit calibration algorithm and the methodology of computing and updating the calibration coefficients determined from the SD and SDSM data sets. We present examples of the sensor's long-term and short-term stability trending of key RSB calibration parameters using over four years of on-orbit calibration data sets. Special considerations due to changes in instrument configuration and sensor response are also discussed.

Long-term, incoming total solar irradiance (TSI) measurement trends were validated using proxy TSI values, derived from indices of solar magnetic activity. Spacecraft active cavity radiometers (ACR) are being used to measure longterm TSI variability, which may trigger global climate changes. The TSI, typically referred to as the "solar constant", was normalized to the mean earth-sun distance. Studies of spacecraft TSI data sets confirmed the existence of a 0.1 %, long-term TSI variability component within a 10-year period. The 0.1 % TSI variability component is clearly present in the spacecraft data sets from the 1984-2004 time frame. Typically, three overlapping spacecraft data sets were used to validate long-term TSI variability trends. However, during the years of 1978-1984, 1989-1991, and 1993-1996, three overlapping spacecraft data sets were not available in order to validate TSI trends. The TSI was found to vary with indices of solar magnetic activity associated with recent 10-year sunspot cycles. Proxy TSI values were derived from least squares analyses of the measured TSI variability with the solar indices of 10.7-cm solar fluxes, and with limbdarked sunspot fluxes. The resulting proxy TSI values were compared to the spacecraft ACR measurements of TSI variability to detect ACR instrument degradation, which may be interpreted as TSI variability. Analyses of ACR measurements and TSI proxies are presented primarily for the 1984-2004, Earth Radiation Budget Experiment (ERBE) ACR solar monitor data set. Differences in proxy and spacecraft measurement data sets suggest the existence of another TSI variability component with an amplitude greater than or equal to 0.5 Wm-2 (0.04%), and with a cycle of 20 years or more.

Since the launch of MERIS on ENVISAT long term activities using vicarious calibration approaches are set in place to monitor potential drifts in calibration in the radiance products of MERIS. We are using a stable, well monitored reference calibration site (Railroad Valley, Nevada, USA) to derive calibration uncertainties of MERIS over time. We are using interpolation of uncertainties to derive a second set of uncertainties for a national data validation in the Netherlands. A satellite image derived land use map of the Netherlands (LGN4) is used to determine the largest homogeneous land use classes using a standard purity index (SPI). Potential adjacency effects are minimized using moving window filters on the pixels of the aggregated map. Multiple error propagation is being used to assess the impact of calibration accuracy on land use classification. A classification in 9 land use classes is finally performed on MERIS FR images of the Netherlands using image based spectral unmixing and matched filtering with endmembers derived from the LGN. We conclude that the classification performance may significantly be increased, when taking into account long-term vicarious calibration results.

Envisat is ESA's environmental research satellite launched on 1 March 2002. It carries a suit of sensors offering opportunities for a broad range of scientific research and applications. The radiometric calibration results from the first 2 years of operation of the MEdium Resolution Imaging Spectrometer (MERIS) will be presented. Radiometric calibration using the on-board diffuser will be discussed and compared with the results from a number of vicarious calibration methods and the image quality of instrument will be assessed.

Envisat is ESA's environmental research satellite launched on 1 March 2002. It carries a suit of sensors offering opportunities for a broad range of scientific research and applications. The spectral calibration results from the first 2 years of operation of the MEdium Resolution Imaging Spectrometer (MERIS) will be presented. Four different methods, Making use of the spectral programmability of the instrument, were used to characterize the five MERIS spectrometers at eight wavelengths covering most of the useful spectral range of the instrument. The onboard spectral calibration uses an Erbium doped SpectralonTM diffuser panel providing useful absorption features at 408 & 522 nm. Configuring the instrument band settings to cover a designated spectral ranges with narrow bands, and acquiring data over natural targets for a limited number of orbits, as well as using the on-board radiometric (white) SpectralonTM diffuser; the instrument's response to a number of Fraunhofer absorption features {395, 486, 656, 854 & 866 nm}, and atmospheric oxygen absorption {760nm} where analysed. The methods and results of this analysis will be presented as well as the final MERIS spectral model derived from these.

Since 2002-03-01 the spectrometer SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) is in a sun-synchronous polar orbit around the Earth aboard the new European environmental satellite ENVISAT. SCIAMACHY measures during its lifetime concentrations and distributions of atmospheric trace gases such as O₃, BrO, OClO, ClO, SO₂, H₂CO, NO₂, CO, CO₂, CH₄, H₂O, N₂O, metals, clouds, and aerosols. The quality of these data products depends both on the calibration of the instrument and the detailed knowledge of the instrument's status and behaviour at any time during the whole mission. To achieve this a comprehensive monitoring concept has been developed and implemented. This paper gives a brief overview of the instrument and the calibration and monitoring concepts. Results of the performance monitoring activities from nominal operations of the instrument show that SCIAMACHY in general is in good shape. The radiometric calibration of the instrument could be enhanced by a thorough revision of the on-ground calibration. An ice-layer buildup is observed on the IR detectors, which shall be compensated by a throughput correction factor.

Spectral oscillation features originating from the on-board diffuser in the spectra of the SCIAMACHY instrument on ENVISAT have been observed in instrument data. These spectral diffuser surface interference features are observed in the daily sun-over-diffuser calibration measurements (solar irradiance). The effect may hamper the analysis of atmospheric trace gases. Diffuser spectral features were already known from the on-ground calibration phase, which led to the implementation of a second diffuser in SCIAMACHY to reduce the features magnitude. Spectral features like these have already been observed at TNO TPD during the on-ground calibration for instruments that utilise on-board diffusers (i.e. GOME-2, OMI). Analysis of the characteristics of the features indicates different types, where at least one type shows a pattern typical for speckles. In addition a separation method of the different features present in the spectrum will be described.

High resolution images of the Earth surface in the visible wavelength are useful in a variety of human activities, from agriculture, to urban area monitoring, but the utilization is often limited by the high cost of the images and the relatively small number of satellites equipped with high resolution telescopes. In order to encourage the utilization of high resolution images, Italian Space Agency (ASI) funded a project aimed to investigate the possibility of utilization of microsatellites for this task. The objective of the project MITAR (MIcro Telescope, high Resolution) is to realize a prototypal telescope, capable of a 1m resolution from 400Km altitude, compatible with a microsatellite platform. The necessity of a compact, lightweight and highly performing payload has been achieved designing a Cassegrain configuration with composite material mirrors and an innovative deployable structure. The feasibility analysis and preliminary design have been presented at the SPIE Remote Sensing Europe 2003 congress in the paper titled "High resolution deployable telescope for satellite application". Present paper focuses on the activities developed by Second University of Naples. In the university it has been designed a structure capable of a smooth deploy, without active control systems. The structure is deployed by lenticular tape springs (LTS), damped with viscoelastic polymer. In the paper it is quickly described the optical system, then the peculiarity of the lenticular tape springs are shortly described. The characterization of the visco-elastically damped LTS (VEDLTS), and the description of the efforts aimed to have numerical and analytical instruments for the prediction of this innovative elements are exposed with more details. We report then some relevant detail of the deployable structure and the realization related aspects. The paper is concluded with the results of the very preliminary tests, aimed to verify the ability of the structure of performing a correct deploy and the accuracy of the deployed configuration. The tests have evidenced that the structure does not easily deploy spontaneously, then it has been necessary to use some conventional springs in order to trigger a correct deploy, obtaining a structure with the needed characteristics.

The new airborne CRyogenic Infrared Spectrometers and Telescope for the Atmosphere experiment (CRISTA-New Frontiers) succeeds the CRISTA satellite instrument operated twice during NASA space shuttle flights in November 1994 (STS 66) and August 1997 (STS 85). The first mission of the instrument will take place aboard the high altitude research aircraft M55-Geophysica in a campaign in the tropics in 2005/06. CRISTA-NF is a limb-scanning instrument measuring thermal emissions of various atmospheric trace gases (e.g. water vapor, ozone, chlorofluorocarbons), clouds and aerosols in the mid-infrared spectral region. The incoming radiation entering the optics through a Herschel telescope is analyzed by two Ebert-Fastie grating spectrometers with moderate spectral resolution and finally registered by cryogenic semiconductor-detectors. The optical system is integrated into a compact cryostat which reaches temperatures down to 10K by cooling with supercritical helium. This allows fast measurements and provides good signal-to-noise ratio. A narrow vertical field of view (200m) results in high vertical resolution which is neccessary for the analysis of small scale dynamic processes especially in the upper troposphere and lower stratosphere. This paper gives a scientific motivation, some remarks on the measurement technique and an overview of instrument design and technology.

In the framework of the Radiation Explorer in the Far InfraRed space mission for the characterization in the far infrared of the Earth outgoing emission, a breadboard version of the Fourier transform spectrometer, which is the core instrument of the payload package, has been developed. The Fourier transform spectrometer operates in the spectral range of 100-1100 cm^-1 with a resolution of 0.5 cm^-1, 6.5 s acquisition time, and signal-to-noise ratio better than 100. It is a compact prototype designed both for laboratory applications and for field campaigns, in particular for operations in high-altitude ground-based sites and on-board of stratospheric balloon platforms. This paper describes the instrument characterization performed in laboratory conditions and under vacuum. The study has allowed to study the trade-off among all the instrument parameters and to test the new optical design of the interferometer, with particular attention to the photolithographic beam splitters and the room-temperature pyroelectric detectors. The instrument was operated for the first time in a field campaign in June 2004 from 1247~m altitude ground-based site located in the South of Italy. The results of this test and the comparison with the measurements taken with a BOMEM spectrometer, that partially overlaps the REFIR bandwidth in the higher spectral region, are reported. Info can be found at http://radiation.ifac.cnr.it.

APEX is a dispersive pushbroom imaging spectrometer operating in the spectral range between 380 - 2500 nm. The spectral resolution will be better than 10 nm in the SWIR and < 5 nm in the VNIR range of the solar reflected range of the spectrum. The total FOV will be ± 14 deg, recording 1000 pixels across track with about 300 spectral bands simultaneously. A large variety of characterization measurements will be performed in the scope of the APEX project, e.g., on-board characterization, frequent laboratory characterization, and vicarious calibration. The retrieved calibration parameters will allow a data calibration in the APEX Processing and Archiving Facility (PAF). The data calibration includes the calculation of the required, time-dependent calibration coefficients from the calibration parameters and, subsequently, the radiometric, spectral and geometric calibration of the raw data. Because of the heterogeneity of the characterization measurements, the optimal calibration for each data set is achieved using a special assimilation algorithm. In the paper the different facilities allowing characterization measurements, the PAF and the new data assimilation scheme are outlined.

APEX (Airborne Prism EXperiment) is a project of the European Space Agency ESA focusing on high accuracy simulation, calibration and validation for spaceborne remote sensing instruments. The instrumentation comprises a hyperspectral imager for various standard airborne platforms, a fixed installed calibration home base and a complete facility for data processing and archiving. The pushbroom-type instrument accommodates two spectrometer channels covering a spectral range from 0.38 up to 2.5 micron. The spatial/spectral resolution amounts to 1000 samples at 28-degree field of view with 312 spectral bands. The overall instrument design and its built-in characterization unit will allow excellent performance stability under various flight conditions. The presentation will focus on the design, development and realization phases of the instrument and discuss various highlights of technical achievements, as there are the infrared HgCdTe detector with extended array format for the short wave infrared channel, the thermal/mechanical stabilization of the spectrometer and the realization of the infrastructure for high accuracy characterization and calibration of the instrument.

We present new characterization results for a large format, 15 um pixel pitch, 2kx4k format, p-channel CCD fabricated on high resistivity silicon at Lawrence Berkeley National Laboratory. The fully-depleted device is 300 um thick and backside illuminated utilizing 4-side buttable packaging. We report on measurements of standard operating characteristics including charge transfer efficiency, readout noise, cosmetics performance, dark current, and well depth. We have also made preliminary measurements of the device's X-Ray energy resolution and tests of device linearity.

In this paper we report on the CEA/LETI infrared laboratory activity in both HgCdTe cooled detectors and amorphous silicon uncooled microbolometers. An overview of the recent developments will be given while the future perspectives of these IR technologies will be highlighted in the context of space applications. The unique realization of a megapixel HgCdTe MWIR focal plane array with a 15μm pitch was completed in 2003. The electro-optical performances at LN temperature of this high resolution IRFPA will be given extensively. Beside this large 2D array achievement, CEA/LETI is strongly involved in the development of an innovative cooled multispectral technology that requires a specific HgCdTe growing process to achieve a stack of two dual band photodiodes in each pixel. This technology primarily relies on the molecular beam epitaxy (MBE) of a multiple (211)HgCdTe films grown on a lattice matched CdZnTe substrate. The device structure will be discussed as well as the elementary detectors characteristics which have been found to exhibit performances very close to those obtained in single colour detectors. The main electro-optical performances obtained at LN temperature of a two colours 128x128 IRCMOS FPA, 50μm pitch, operating sequentially within the MWIR (3-5μm) will be presented. The well establish availability of uncooled infrared detectors has opened new perspectives when miniaturization, weight, power and reliability are of paramount importance. Moreover the recent breakthrough of the performance of these sensors leads to new applications where enhanced resolution is required. The article will review the state of the art of CEA/LETI uncooled IR technology through various examples of focal plane arrays and the future trends of this uncooled technology will be considered. The trade-off between thermal resolution and time constant which is a critical parameter for earth observation will be largely discussed.

Sofradir started to work in the field of space applications and especially in the earth observation domain in the beginning of the 1990th. Thanks to the work done with the support of the French Ministry of Defense and the European Space Agency, Sofradir has acquired a large know-how and became a major supplier for European space industry. Sofradir space technologies offer possibilities to develop a large panel of high reliable detectors like long linear arrays or two dimensional arrays covering bandwidth from 0.8 to 15 μm, answering hyperspectral needs, based on qualified Mercury Cadmium Telluride (MCT) technology. Furthermore, Sofradir has a great experience in the field of packaging and offers complete detectors including dewars and coolers. This paper proposes an overview of Sofradir technology capabilities for design of custom space detectors for earth observation or hyperspectral applications, covering the field of detection, hybridisation, readout circuit, focal plane structures, packaging and test. Finally, this paper presents the last results obtained in the development of infrared detectors for hyperspectral instruments.

Imaging detectors are key elements for optical instruments and sensors on board space missions dedicated to Earth observation (high resolution imaging, atmosphere spectroscopy...), Solar System exploration (micro cameras, guidance for autonomous vehicle...) and Universe observation (space telescope focal planes, guiding sensors...). This market has been dominated by CCD technology for long. Since the mid-90s, CMOS Image Sensors (CIS) have been competing with CCDs for consumer domains (webcams, cell phones, digital cameras...). Featuring significant advantages over CCD sensors for space applications (lower power consumption, smaller system size, better radiations behaviour...), CMOS technology is also expanding in this field, justifying specific R&D and development programs funded by national and European space agencies (mainly CNES, DGA and ESA). All along the 90s and thanks to their increasingly improving performances, CIS have started to be successfully used for more and more demanding space applications, from vision and control functions requiring low-level performances to guidance applications requiring medium-level performances. Recent technology improvements have made possible the manufacturing of research-grade CIS that are able to compete with CCDs in the high-performances arena. After an introduction outlining the growing interest of optical instruments designers for CMOS image sensors, this paper will present the existing and foreseen ways to reach high-level electro-optics performances for CIS. The developments and performances of CIS prototypes built using an imaging CMOS process will be presented in the corresponding section.

MTF measurement methods for imaging devices usually require the use of an optical system to project the image of the object onto the detector. So, MTF results quality strongly depends on the accuracy of the optical adjustments (alignments, focusing...). Dedicated edge patterns have been implemented at the chip level on a CMOS imager. One of them emulates the target used in the ISO 12233 slanted-edge technique and the others one are inspired by the knife-edge method. This allows to get the MTF data without optical focusing. In order to validate the results, comparisons have been made between MTF measurements using these patterns and results obtained through direct measurements with the transmissive slanted-edge target and sine target.

Since the end of 1970s, EADS-SODERN has developed a series of detection units positioned in the focal plane of earth observation instruments and mounted on the French civil and military satellites like SPOT and HELIOS. Those detection units, designed for a push broom operating mode, have been progressively adapted to match the technical evolutions of the programmes. With PLEIADES High Resolution optical satellite CNES is proposing a completely new concept which has the capability to acquire the wide-swath of 20 km at nadir with panchromatic and multispectral imagery and a panchromatic mode resolution of 0.7 m at nadir. Within the industrial structure of this new programme, EADS SODERN is responsible for the development of the Focal Plane Assembly (FPA). This FPA, which is one of the most significant parts performing the imaging function, offers a wide variety of new technologies. This paper describes the design and performance budgets of this new FPA: o The mechanical support and thermal control with the Silicon Carbide (SiC) structure allows evacuating the detectors dissipation while maintaining stable the detection lines. o The folding mirrors are used to achieve the required limitation of panchromatic / multispectral distance with the constraint of detectors package size. o The spectral selection is made by strip filters place very close in front of the detectors.

Since 1993, the EC DG Agriculture has promoted the use of "Controls with Remote Sensing" (CwRS) as appropriate control system within the Common Agricultural Policy (CAP). CwRS is considered suitable to check if agricultural area-based subsidies (yearly > 25 billion euro EC expenditure) are correctly granted. On the basis of the Council Regulation (EC) 165/94 and of the Commission Regulation (EC) 601/94, the Commission Services are required to centralize the satellite images acquisition. This task has been managed by the MARS Project at the JRC since 1999, where the whole controls activity is coordinated. The activity also includes the setting up of specifications, recommendations, performing Quality Controls (QC) and auditing of the selected contractors, and evaluation of new methods. Satellite image acquisition involves the control site definition within each Member State, and the subsequent chain of image acquisition over the defined sites including feasibility with image providers, acquisition, validation, ordering, delivery and final archiving of the imagery. In summary the 2004 years campaign involved a budget of approximately 3.2 M euro to cover some 150 High Resolution (HR) sites and 71 Very High Resolution (VHR) sites. The objective of this paper is to describe the CwRS image acquisition with emphasis on the Ikonos, Quickbird, and EROS A satellites for the 2004 years CwRS Campaign, to give preliminary results, recommendations and future trends.

Preprocessing of AVIRIS and Hyperion hyperspectral data is a challenging and time consuming process. A significant portion of this preprocessing effort is related to the removal of specific bands for the selection of an optimal band set. Bad bands are characterized by criteria such as noise and low responsivity. Noise is the interference resulting from atmospheric absorption phenomena and may be sensor generated. Responsivity refers to the bands representing wavelengths near the extremes of the sensors' focal plane(s). This research streamlines the preprocessing flow, thus minimizing production time and effort. In addition, this overview will help to expand the user community beyond remote sensing experts and facilitate the accessibility of hyperspectral data to application experts in various fields. This will be accomplished by improving the end user's understanding of the preprocessing steps and their ability to interpret these data types.

An innovative tunable diode laser (TDL) measurement system has been used for the on-line estimation of emissions of cars, driving through the measurement beam of the system. This paper describes the measurement principle and gives first measurement results, taken for different types of cars.

Satellite remote sensing is coming to be a useful high tech of fast and large-scale measurement for observation and inspection day by day. With the rapid development of satellite sources, it is necessary to design and construct a steady-going and automatic operational satellite data processing system to meet the requirement of marine operation application. In this paper, the data processing technique for multi satellites, such as FY-1C/D, NOAA12/14/15/16/17 and EOS/MODIS, are discussed, including multi satellite combination processing programming, database, Windows sockets mechanism etc. The system has been constructed and tested in Second Institute of Oceanography, State Oceanic Administration, which can automatically provide the remote sensing products for marine application, such as sea surface temperature, chlorophyll, suspended material, diffusing attenuation coefficient of 490 nm, secchi disk depth, vegetation index, optical thickness and so on. The results primary shows that the constructed system is suitable to process multi satellites for marine operational application.

In the past decade, the number of Earth observation satellites has burgeoned. EO missions have been conceived to study different aspects and interacting pieces of the Earth system and scientists are designing increasingly complex, interdisciplinary campaigns to exploit multiple EO assets. In general, each EO mission has its own observation scheduling system, leading to a diverse array of specialized scheduling systems each tailored to a mission's unique requirements and characteristics. There is therefore the opportunity to allow planning and scheduling algorithms to assist a scientist requesting a set of observations, optimized over multiple sensors, to meet a science goal. This paper addresses the formal specification of a request to allow such algorithms to be exploited. The most basic parameters of a campaign request include the list of sensors required or desired in combination with the time frames or intervals and geographic regions for which the observation(s) are needed. Temporal and geographic parameters may be dependent on exogenous events, such as the occurrence of a fire, hurricane, volcanic eruption, or seasonal event. The scientist would also like to specify constraints on the needed quality of observations (e.g. cloud cover) and may have dependencies between parameters. Fulfilling preferences (e.g. new data are preferable to older data) may improve the quality of subsequent scientific analysis. The cost of the set of observations will also be an important contraint. In this paper, we propose a structure for expressing these parameters and constraints. We use a fire emissions model validation campaign as illustration.

An imaging spectrometer covering the 400-1000 nm band has been conceived and developed. The system is based on an Acousto-Optic Tunable Filter (AOTF) attached to a high performance digital camera. The AOTF permits the selection of spectral bands with an RF signal in the range of 70-210 MHz. The range is covered using two transducers attached to a single crystal. Although the idea is not new it covers a broader spectrum than previous systems. It includes a telecentric optical system that enhances system efficiency, by ensuring that the chief ray of each light cone emerges out of this doublet parallel to the optical axes. Additionally, an smart choice of integration time reduces the dependence of the efficiency on the frequency. Calibration includes filter characterisation and compensation of crystal non-constant diffraction efficiency and spatial non-homogeneity. The system is controlled by a PC application, specifically developed for this purpose, providing wide versatility, while enabling transparent and intuitive management to typical users.

As part of an effort to reduce uncertainties in the radiometric calibrations of integrating sphere sources and standard lamp irradiance sources, the Goddard Space Flight Center (GSFC) Radiometric Calibration Facility (RCF) primary radiometer was characterized at the NIST facility for Spectral Irradiance and Radiance Calibrations with Uniform Sources (SIRCUS). Specifically, the radiometer's slit spectral function was measured and the magnitude of out-of-band stray light was determined. The characterization also revealed significant contributions of spectral stray light due to fluorescence of the radiometer's input sphere. The RCF examined the effects of stray light and sphere fluorescence in the radiometer on source radiance calibrations along with approaches to reduce those sources of measurement error.

For over three decades, the Radiometric Calibration Facility (RCF) at NASA's Goddard Space Flight Center (GSFC) has maintained calibrated uniform radiance sources for use by the global remote sensing community. As part of a continuing effort to reduce measurement uncertainties while improving efficiency, the calibration transfer hardware and operational protocols are systematically examined, with improved equipment and techniques being incorporated. This paper describes the optical characterization and presents radiance measurements of a new spectroradiometer, the GSFC 750/Integrating Sphere Irradiance Collector (ISIC), using a new input optical system. The performance of the new input optical system is compared with the two previous input systems.

Many satellite instruments operating in the reflective solar wavelength region between 400nm and 2500nm require accurate and precise determination of the Bidirectional Reflectance Distribution Function (BRDF) of Spectralon diffusers used in their pre-flight and on-orbit calibrations. Calibration measurements of the BRDF of a laboratory optical grade Spectralon diffuse target at different incident polarized light in ultraviolet and visible is presented. The Spectralon diffuser was measured using P and S incident polarized light and over a range of incident and scatter angles from 0 to 60 degrees. The experimental data were obtained using the out-of-plane optical scatterometer located in NASA's Goddard Space Flight Center's Diffuse Calibration Facility's. The typical measurement uncertainty of reported BRDF measurements is 0.7 % (k=1). It is shown how BRDF of Spectralon at P and S polarization of the incident light depends on the incident and scatter angles and on wavelengths. The difference is significant, depends strongly on the incident and scatter angles can be as high as 5.7% at 60 deg incident, 60 deg scatter zenith and 0 deg scatter azimuth angles

The Optical Radiation Measurement (ORM) group of the National Physical Laboratory is responsible for the development of the UK's primary radiometric quantities. One of its principle aims in recent years has been to improve the accuracy of "user" measurements through improved traceability routes to the SI system of units. The Earth Observation (EO) community is arguably the most demanding, requiring specialist techniques and transfer standards. To improve accuracy, NPL has developed a range of lamp illuminated integrating spheres, called Transfer Standard Absolute Radiance Source (TSARS). The TSARS is calibrated directly against the NPL primary blackbody source with uncertainties <±0.75% which can be maintained and confirmed following transportation, through detector stabilisation. To demonstrate the performance of NPL's new TSARS, it was taken to TNO TPD in Delft for inclusion in the radiometric characterisation of the Global Ozone Monitoring Experiment (GOME 2) - FM3. Overall agreement to <± 1% with both TNO TPD and NASA was achieved, demonstrating consistency in international radiometric scales, since the TNO and NASA sources were calibrated traceable to NIST. It also demonstrates the practicality of achieving calibrations with uncertainties <±1%, and since the NPL TSARS is portable, allows similar levels of uncertainty in "field situations" e.g. field spectrometers, aircraft radiometers.

The process of developing new sensors for space flight frequently builds upon the designs and experiences of existing heritage space flight sensors. Frequently in the new sensor development, problems are encountered that pose the risk of serious impact on successful retrieval of geophysical products using the new sensor. This paper describes an approach to assess the importance of optical and electronic cross-talk on retrieval of geophysical products using new MODIS-like sensors through the use of MODIS data sets. These approaches may be extended to any sensor characteristic and any sensor where that characteristic may impact the Level 1 products and their associated higher level geophysical products. In this study, a set of electronic cross-talk coefficients are postulated. These coefficients are sender-receiver influence coefficients and represent a system signal contamination on any detector on a focal plane when another detector on that focal plane is stimulated with a geophysical signal. The approach involves using the postulated cross-talk coefficients on an actual set of MODIS data granules. The original MODIS data granules and the cross-talk impacted granules can be used with validated geophysical algorithms to create the derived products. Comparison of products affected by crosstalk with products without cross-talk will identify potential problems.

Spectro-directional surface measurements can either be performed in the field or within a laboratory setup. Laboratory measurements have the advantage of constant illumination and neglectable atmospheric disturbances. On the other hand, artificial light sources are usually less parallel and less homogeneous than the clear sky solar illumination. To account for these differences and for determining for which targets a replacement of field by laboratory experiments is indeed feasible, a quantitative comparison is a prerequisite. Currently, there exists no systematic comparison of field and laboratory measurements using the same targets. In this study we concentrate on the difference in spectro-directional field and laboratory data of the same target due to diffuse illumination. The field data were corrected for diffuse illumination following the proposed procedure by Martonchik . Spectro-directional data were obtained with a GER3700 spectroradiometer. In the field, a MFR sun photometer directly observed the total incoming diffuse irradiance. In the laboratory, a 1000W brightness-stabilized quartz tungsten halogen lamp was used. For the first direct comparison of field and laboratory measurements, we used an artificial and inert target with high angular anisotropy. Analysis shows that the diffuse illumination in the field is leading to a higher total reflectance and less pronounced angular anisotropy.

The Modulation Transfer Function (MTF) is a major parameter for high resolution optical remote sensing systems, indicating how spatial frequencies are transmitted and weakened by the imaging global chain. Assessing MTF is thus a very important task during both the in-flight commissioning period and the routine monitoring phases. Classical in flight MTF measurement methods are based upon devoted well known patterns such as knife edge patterns. These techniques induce heavy constraints upon satellite payload programming taking into account nebulosity conditions and pattern ground maintenance. Moreover, for high MTF systems, MTF assessment proves to be difficult because the point spread function has a too reduced extension. Another solution consists in taking two images of the same scene, one in a high resolution mode and the other one in a lower resolution mode. When the resolution ratio is high enough (typically higher then 3), it is possible to simulate the lower resolution image through convolution with a filter and undersampling. The least square method consists in an iterative process, according to which the convolution filter evolves in order to minimize a least square criterion measuring the difference between the simulation and the low resolution image. Once the process has converged, taking the Fourier Transform of the convolution filter gives an estimation of the ratio between low resolution image MTF versus high resolution image MTF. This method may be successfully applied to remote sensing systems such as Quickbird, Ikonos, SPOT5 and future PLEIADES-HR to assess MTF in the multispectral mode. The goal of this paper is to present the MTF assessment method, the way it was validated through simulations and its application within SPOT5 context.