1. Overview The German Remote Sensing Data Center, Deutsches Fernerkundungsdatenzentrum (DFD), is a division of Germany's Aerospace Research Establishment (Deutsche Forschungsanstalt fuer Luft- und Raumfahrt, DLR). It is part of the DLR Ober- pfaffenhofen research center near Munich. In addition there is a DFD subsidiary in Neustrelitz, about 100 km north of Berlin. Both sites serve as a national infrastructure to support customers (data providers and users of data products) by receiving, processing, validating and analyzing satellite remote sensing data and satellite navigation data. Further topics are to promote use of these data and to help customers to set up services. 2. Data Center Contact The official contact to the German Remote Sensing Data center is: DLR Deutsches Fernerkundungsdatenzentrum (DFD) Oberpfaffenhofen Postfach 1116 82230 Wessling Germany Tel. +49-8153-28-2650 Fax. +49-8153-28-1137 An alternate postal address may be used for courier service: DLR/DFD Muenchner Str. 20 82230 Wessling Germany 3. Major Tasks and Activities DFD provides data and services to national and international customers, to service providers as well as end users. The major tasks comprise: - development, operation, and management of a payload data ground segment, consisting of several ground stations for the acquisition of Earth observation data, various processors and processing facilities for the generation of high- quality standard data products, and of data and information management systems for the archival and retrieval of all acquired data and derived products, for product formatting and distribution, and for interactive online user services. As an example is cited below the German Processing and Archiving Faility (D-PAF) for ERS-1/2, working on behalf of ESA. - development and operation of ground reference stations for satellite supported navigation and tracking services. - development and utilization of new algorithms for the generation and validation of high-level data products to be used in pilot projects, for the development of new applications, and for training and education purpose. - provision of system engineering support and project management services for the development of complex data systems in context of large projects. To a certain extent the system engineering services include also the development, test, and integration of on-board and ground-support equipment for spaceborne sensor components. 4. Technical Infrastructure The technical infrastructure, used to perform the above services, comprises a complex ground segment network consisting of several ground stations, of various dedicated processing systems operating in a distributed computing environment, and of multimission information and data management systems. 4.1 DFD Ground Stations 4.1.1 Data Acquisition Facilities in Oberpfaffenhofen The DLR research center in Oberpfaffenhofen is located in Bavaria, about 25 km west of Munich (48.09_N, 11.28_E, 582m above sea level). The following DFD ground stations are operated on a routine basis: - L-Band station, acquiring up to six passes per day of NOAA-HRPT (AVHRR and TOVS) data. The station is part of the European TIROS network, coordinated by ESRIN. It is operational since 1982 and will also be used to acquire the SeaWiFS data of SeaStar. - Primary Data User Station (PDUS), providing real-time access to METEOSAT data. PDUS raw data as well as value-added products are made available in coordination with EUMETSAT and the German Weather Service (DWD). - BDDN data acquisition facility, performing the reception of ERS-2 GOME data. - PRARE Dumping Station, acquiring all tracking data from the ERS-2 onboard storage facility, collected from the PRARE station network - this for further processing to be done at the D-PAF. 4.1.2 Data Acquisition Facilities in Neustrelitz Neustrelitz is located in Mecklenburg-Vorpommern, about 100 km north of Berlin (13.680 E, 53.366 N, 76 m above sea level). It operates the following facilities: - X-Band station, being with a 7.2 m autotrack antenna the main ground station in Neustrelitz. It was implemented to receive and record data from the German MOMS-2P and MOS instruments on the PRIRODA module of the Russian MIR station, as well as from the German MOS sensor on the IRS-P3 spacecraft. The station can also be used to support the Russian RESURS and OKEAN missions. It has been up- graded to acquire ERS SAR data in support of national science requirements. In view of additional requirements and the required high availability and reli- ability of the station in support of commercial customers (e.g. IRS-1B/1C data for Euromap), the implementation of a second X-band station has been started. It will be available mid 1997. - S-Band station, performing the reception of NOAA- and METEOSAT data in support of special projects, and serving as back up for similar facilities in Oberpfaffenhofen. - reference station, being operated for the experimental use of the American and Russian satellite navigation systems GPS and GLONASS to support DLR research tasks. - UHF/VHF receiving capabilities for APEX and CORONAS. 4.1.3 German Antarctic Receiving Station The German Antarctic Receiving Station (GARS, at 63.32_S, 57.90_W, 15 m above sea level) is a permanent installation, located at the northern part of the Antarctic peninsula in the direct vicinity of the Chilean base O'Higgins (named after General Bernardo O'Higgins). The station is designed for both data reception from remote sensing satellites in X-Band and S-Band, and for Very Long Baseline Interferometry (VLBI). O'Higgins is accessible throughout the year; GARS is presently operated in three to four data acquisition campaigns per year with durations of four to eight weeks each. Since October 1991 the station has been receiving ERS-1 SAR data in support of national and international scientific research programmes, carried out on the Antarctic peninsula with its ice shelves and in its surrounding water bodies. A limited number of NOAA-AVHRR passes were also recorded, and selected passes of JERS-1 SAR data have been acquired. 4.1.4 Transportable Receiving Station The German Transportable Receiving Station (TRS) was designed for installation at sites where data acquisition of satellite remote sensing data is not yet possible, where multimission capacity is not sufficient, or where exceptional events such as natural disasters require rapid availability of Earth observation data. The technical design therefore concentrated on a transportable station with the smallest possible antenna diameter (8m), still providing the required performan- ce for S-Band and X-Band reception of high-rate sensor data from satellites such as ERS and JERS. The station was deployed at the equatorial ESA site in Gabon, Africa. It is presently being operated on a campaign basis for the acquisition of ERS SAR data in support of the TREES project of JRC. 4.1.5 Mobile Receiving Station A mobile X-Band receiving station for ERS SAR data acquisition has been jointly procured together with the GeoForschungsZentrum Potsdam (GFZ), Potsdam. With an antenna of 4.0 m diameter it will have a slightly reduced visibility circle. The station is presently in a commissioning phase for data acquisition at Cordoba, Argentina (Jan. 1997). There are plans to procure a further station of same type. A candidate site for deployment is Kitab in Usbekistan. 4.2 Processing Facilities The German Processing and Archiving Facility (D-PAF) for ERS is the largest in- tegrated processing facility of DFD. It is part of the ESA ground segment for the off-line processing and archiving of ERS- 1/2 sensor data. The facility was implemented in cooperation with GFZ staff at DFD in Oberpfaffenhofen. It is jointly operated under contract to the European Space Agency since the launch of ERS-1 in July 1991. D-PAF is composed of the following major processing facilities: - SAR Data Processing Facility, consisting of the Multisensor SAR Processor (MSAR) and the Geocoding System (GEOS), both to generate high-level standard products for ERS-1 and ERS-2 SAR data as well as for JERS-1 SAR data. - Radar Altimeter and Tracking Data Processing Facility, consisting of the PRARE System (PRS), the Tracking Data and Orbit Processing System (TOS), and the Altimeter Data Processing System (ADP) to systematically generate Precise Orbits, to improve the ERS gravity field models and to support the generation of geophysical products such as Sea Surface Height and Topography from the global RA coverage. - GOME (Global Ozone Monitoring Experiment) Data Processor GDP, being used to systematically process all data from the GOME sensor to product levels 1.5 and 2. - Data Management System (DMS), used to centrally initialize product generation, to control and monitor the above production facilities, and to catalogue all generated products which finally are all stored in the DFD archive. On request, DMS initiates that products are copied to different media for subsequent distribution to users. Through DFD's cooperation with GFZ, the D-PAF also coordinates the international Laser Tracking Network. In context of the X-SAR project, jointly performed by DARA/DLR/ASI, the X-SAR Processing System (XPS) was developed to ingest raw X-SAR data from HDDTs and to generate standard products such as `Single Look Complex Images' and `Precision Images' from which higher level products are derived. The XPS is an integral part of the D-PAF SAR Data Processing Facility. In Neustrelitz the processing and archiving facility is co-located with the acquisition facilities. It consists of the following processing systems: - MOMS-02 processing system, used to generate system-corrected products from all MOMS-02 data recorded during Shuttle flight STS-55 in 1993. - two MOS data processors, used to generate radiometrically corrected and cali- brated products from the MOS instruments onboard of the PRIRODA module, as well as from MOS on IRS-P3 acquired in 1996. - processing facility, used to generate system-corrected MOMS-2P products from the raw data acquired with the X-Band station in 1996. - data base management system, used to catalogue the metadata of all products generated with the above processing systems and to ingest this information into the ISIS inventory (see below). In addition a variety of value added products are generated at DFD (Oberpfaffenhofen) with the following systems: - NOAA processing chain, used to generate in addition to various standard products also products such as SST, NDVI and geocoded data sets. - several systems for image processing, data visualization, and for the generation of special products such as maps, mosaics, multitemporal and multisensoral thematic products. - a processor to derive different GOME level 3 data products to observe global distribution of atmospheric Ozone. Some of these systems are operated in near real time, others off-line, but most are used on a systematic basis. 4.3 Data Archive, Distribution, and Information Systems While the processing systems are more or less mission dependent, the data archive, distribution, and information systems are central facilities that support all projects and missions. These central facilities comprise: - several off-line archives for HDDTs, CCTs, EXCs, and optical disks, as well as online archives on disks and jukeboxes, and the new robotic tape libraries in Oberpfaffenhofen and Neustrelitz (being interlinked), into which all DFD data holdings will finally be migrated. - Intelligent Satellite data Information System (ISIS), combining the basic inventory function of all DFD data holdings and the interactive graphical user interface based on a server/client architecture. ISIS allows users to perform inventory searches via electronic links, to browse through reduced-resolution images, to access selected products, and to accept orders for offline delivery of products. ISIS supports also interconnection to worldwide-available `directory information' which is offered by a `cooperating node' of the CEOS International Directory Network (IDN). This network is based on NASA's Global Change Master Directory (GCMD). IDN provides guide information like detailed descriptions of sensors, data sets, and data products. - Product Generation System (PGS), used to access and reformat the archived digital data for delivery to users via FTP, on digital media (CCT, EXC, CD-R, etc.), or for recording on film and subsequent photographic processing. - Photolaboratory (PL), being equipped with devices for processing, copying, and enlarging imagery to generate high quality photographic products on film and paper in black and white, as well as in color. - several FTP-servers, used to electronically distribute low to medium volume products such as SSTs, precise ERS orbit data, low resolution SAR images, etc. These systems are under redesign (1996/97) and will be replaced by the Data and Information Management System (DIMS) which will offer an enhanced functionality as a single integrated system (planned to be operational for 1997/98). 4.5 User Services DFD user services are offered by means of electronic information systems and by a Help Desk function as well. To receive up-to-date general information it is strongly recommended to access the WWW-service first. 4.5.1 WWW - Service The WWW-service offers information about the DFD in terms of major tasks, technical infrastructure, services, contacts, data holdings, and product ordering. The DFD homepage can be accessed with any Web-Browser navigating to: "http://www.dfd.dlr.de" 4.5.2 ISIS The Intelligent Satellite data Information System (ISIS) is DFD's central information system. It should be the first choice for queries if the interest is in DFD data holdings and products in terms of availability, quality, prices and ordering information. The system also supports access to browse products, it provides thesaurus-assisted searches and general textual information in an `info board'. ISIS has been developed as a client/server configuration. It supports an ASCII terminal version as well as a comfortable graphical interface for users. The client software is available free of charge via an FTP-server. Detailed and up-to-date information on how to access ISIS and how to get the client software can be found on the Web-Server, navigating to: "http://www.dfd.dlr.de/ISIS/index.html" 4.5.3 Help Desk If no systems are available at the customer's site that allow access to the WWW-service and/or to ISIS, or if these services do not provide the desired information, then customers are requested and welcome to contact the Help Desk. DLR/DFD - Help Desk Postfach 1116 82230 Wessling Germany Tel: +49-8153-28-2802 Fax: +48-8153-28-1343 e-mail: helpdesk@dfd.dlr.de Additional help-desk information, especially on further technical contacts in different areas of expertise are also provided via the WWW-service under the term `Help Desk'. 4.6 Archived Data Sets and Products With fall of 1996 the DFD archive contains the following data sets, comprising sets of raw data as well as products at various processing levels. 1) Spacelab Metric Camera All black and white and color images taken with the Metric Camera during its flight on the first Spacelab Mission (November/December 1983). 2) Spacelab MOMS-01 All data of the two Shuttle/Spacelab Missions in June 1983 and February 1984. 3) LANDSAT MSS and TM Some selected LANDSAT-1/2/3 MSS data from 1977 to 1988 and LANDSAT-4/5 data from 1982 to 1990, primarily relating to the ground coverage of Germany. 4) SPOT-1 HRV - XS and - P Some selected data and products from February 1986 to February 1990 primarily relating to the ground coverage of Germany. 5) NOAA Data and Products The complete set of NOAA data archived comprises the HRPT data which were ac- quired systematically (4 to 6 passes per day) from the series of NOAA's TIROS satellites since 1982 and various value added products, such as SST and NDVI since 1993 and 1994. Selected passes acquired with the German Antarctic station (GARS) are also available. Browse products are available from ISIS. 6) SEASAT SAR Selected sets of raw data and SAR images from over Europe (processed by DFD on behalf of ESA). Data were acquired at the Oakhanger station (UK) during the three months satellite lifetime in 1978. Browse products are available from ISIS. 7) ERS SAR Data and Products SAR data and products from ERS-1 since July 1991 and from ERS-2 since April 1995 acquired at ESA ground stations in Europe (Kiruna, Fucino, Maspalomas), from GARS, from the German Transportable Station (TRS) and selected passes from several other stations worldwide. Browse products are available from ISIS. 8) ERS Radar Altimeter Products Quick Look Products as well as the complete set of various geophysical products from both missions, such as Sea Surface Height and Topography, and Ocean Geoid. 9) ERS Orbit Products These products comprise the complete set of highly precise orbit data for both ERS spacecrafts as calculated by GFZ/D-PAF from laser tracking data as well as from PRARE data (ERS-2 only). In addition, Earth gravity models are derived from these data. 10) ERS-2 GOME Data Products The GOME data set comprises all GOME instrument data that have been acquired after the launch of ERS-2 in April 1995, as well as all derived level 1.5 and level 2 data products. Data products have been available since completion of the extended instrument commissioning phase in August 1996. In addition various level 3 products are being regularly produced by DFD. Browse products are available from ISIS. 11) JERS-1 SAR SAR data from JERS-1 since February 1992, acquired at NASDA, ESA ground stations and German Antarctic ground station GARS. Only a few processed data sets are available in the DFD archive. 12) Shuttle Radarlab X-SAR All X-SAR data, raw data as well as various products at different processing levels from the two Shuttle Radarlab missions on STS-59 from April 9-20, 1994 and on STS-68 from September 30 to October 11, 1994. Browse products are available from ISIS. 13) Spacelab D2 MOMS-02 All data of the instrument from Shuttle flight STS-55, in April/May 1993. Browse products are available from ISIS. 14) Auxiliary Data Some of these auxiliary data are needed for product generation, such as predicted ERS orbit data, digital elevation models, etc.. These data are kept in the DFD archive, but are available only with special agreement. 15) Special Products A number of special products - mostly value added - are available, such as e.g. radar maps from Germany and from the Antarctic peninsula derived from geocoded terrain corrected products, etc.. Browse products are available from ISIS. 16) Future Products Further products are planned for the near future. These comprise MOS on PRIRODA and IRS platforms, MOMS on PRIRODA as well as various atmospheric data. Not all of the above data sets can be ordered directly at DFD. The following restrictions apply: - all ERS and JERS data products can only be ordered from the commercial distributors (like Eurimage) and from ESA/ESRIN (Principal Investigators only). - all basic LANDSAT and SPOT data products are for DLR internal use only, but higher level products can be ordered at DFD. However, all browse images derived with reduced resolution from the digital image products can be accessed and displayed with ISIS clients (a Web version is being implemented). Altogether, about 70 different data products are archived. For more updated information please access DFD's homepage on Web with URL: "http://www.dfd.dlr.de" This information has been compiled by H. Schroeter DLR/DFD (Jan 1997). email address: schroete@dfd.dlr.de
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