During the early years of remote sensing, extracting useful information from raw satellite data was limited to large companies that could process the digital data in large mainframe computers. There were no laptops, no workstations, no Global Positioning System (GPS), no GIS. Now, with the advent of inexpensive computing capabilities, sophisticated data processing, GIS, GPS and rapid telecommunications through avenues such as the Internet, today's user of satellite remote sensing imagery can be almost anyone anywhere with the appropriate tools.
This shift vastly increases the user market for such capabilities and, perhaps more importantly, for the information and intelligence that can be derived for many uses from many previously disconnected data sources. To help you make your way through today 's Earth imagery maze, here's a quick look at remote sensing sensors, platforms and the digital data they provide to the user community, as well as a preview of major changes in new sensor and satellite/airborne systems. For information on today's growing list of remotely sensed data, see "Access Remote Sensing Data for GIS," page 45. Contact information and acronym definitions for many satellite systems are provided in "Satellite Pl atforms and Sensors,".
Current sensors and platform systems evolved from three primary digital spectral imaging programs: the international meteorological satellite program led by the U.S. National Oceanic and Atmospheric Administration INOAA) in the late 1960s, and the U.S. L andsat and French SPOT programs initiated in 1972 and 1984, respectively.
Meteorological sensors, including NOAA's Advanced Very High Resolution Radiometer {AVHRR), provide a plethora of meteorological data. This government-produced database provides abundant information sources to the commercial user community through commerci al value-added resellers (VARs). Commercial applications include television satellite weather reports and other uses of meteorological data such as commercial agricultural commodity information services. AVHRR data information users also work in the fishi ng, shipping, agriculture, timber, petroleum and mineral industries.
The Landsat and SPOT programs provide complementary stereo, medium-resolution 110-30 meters), visible, infrared and thermal infrared spectral data in various hard-copy formats, as well as data tapes, disks and other digital formats for use by GIS and othe r data processing users.
These mainstays of operational satellite programs for the commercial user community are supplemented by several international programs developed since the mid-1980s such as India's Indian Remote Sensing {IRS) satellite, 1988; Japan's Marine Observing Sate llite (MOST, 1987, and Japan Earth Resource Satellite |JERS), 1992; and the European Space Agency's Earth Resources Satellite {ERS), 1991. The ERS, JERS and MOS satellites variously combine spectral imaging with passive microwave and active radar sensor d ata for land, marine and ice observations. (These systems and more are detailed in "Satellite Platforms and Sensors," page 46.) A wide community of VARs and their parent companies provide GIS users access to these data sources.
These and other sources can provide information to other lesser available satellite data, such as Soviet/ Russian satellite data. Notable among Russian remote sensing data available to the commercial user community are ALMAZ radar data and PrirodaResurs h igh-resolution 12-3 meters) digitally scanned multispectral film data. Although beyond the scope of this article, airborne imaging remote sensing systems also provide a growing source of remote sensing data to complement aerial photography and satellite r emote sensing systems.
Throughout the world, the development of satellite and space sensor technologies traditionally is researched, funded and developed by national security organizations, particularly in the United States and the former Soviet Union. Throughout the Cold War, the two countries viewed control of satellite remote sensing technologies paramount to holding an intelligence "high ground." That was particularly true for issues regarding coverage {including timeliness of civil access and data delivery), imaging spectr a (especially radar) and spatial resolution. Although military control of the technological development of civil satellite systems remains, the end of the Cold War produced major changes in government policies restricting the development of new satellite remote sensing capabilities.
For example, although military radar satellite systems were developed extensively in the United States and Soviet Union, civil development of radar systems was limited to experimental radar sensors flown on the Space Shuttle, such as Shuttle Imaging Radar ISIR) A, B and C. The follow-on commercial development of NASA's free-flying radar satellite, SEASAT-A {1976), did not proceed as planned for national security reasons. Russian radar, as well as film and digital high-resolution spectral photographic data , became available in a limited way in the early l990s. In recent years, satellite radar data have become available for the commercial user community through ESA and Japan's ERS and JERS programs. In 1995, Canada plans to launch RADARSAT, the most sophist icated radar system to date, providing important radar data to the GIS and commercial user communities. Radar works in all kinds of weather and at night, providing textural, moisture and topographic data to supplement data from spectral imaging satellite systems.
The end of the Cold War also brought another significant policy change to the GIS community: the U.S. government's decision in the spring of 1994 to allow the civil commercial development of remote sensing satellite systems providing higher spatial resolu tions. The new policy will expand the remote sensing information industry, allowing imagery with 1meter spatial resolution, and broaden satellite remote sensing commercial user markets. The decision was in response to the U.S. government's interest in bro adening the post-Cold War transfer of defense technologies, as well as the government's awareness that international technologies and plans were going to lower the resolution limit. That would further erode the presumed U.S. leadership in civil satellite remote sensing if other countries develop the 1-meter data market first.
Under the new 1-meter licensing provisions now in force in the United States, three major high-resolution 11-3 meters) systems race to be "first in space," starting probably in 1996. The first up probably will be WorldView, a system being built by WorldVi ew Inc. and supported by CTA Corp. with Ball Aerospace, Telespazio and others. The system is based on concepts developed by engineers from Lawrence Livermore Labs previously working on the Defense Department "Brilliant Pebbles" program. WorldView will pro vide three-band visible near infrared (VNIR) spectral data at 15meter resolution sharpened with a 3meter panchromatic band. WorldView also will provide innovative data access through electronic transfer of data to subscribing users, including those in the GIS community.
Probably closely following WorldView into space will be Eyeglass- built by a consortium that includes Orbital Sciences Corp., Litton's Itek Optical Systems Division and GDE Systems Inc., recently sold to Tracor Corp.-and Space Imaging Inc.'s CRSS system f rom Lockheed Space and Missiles Corp., in a joint venture with E-Systems Inc. The Eyeglass and Space Imaging systems will provide 1-meter panchromatic data.Space Imaging also will provide three-band VNIR data at meter resolution. As with the design of all space systems, improving one on board parameter usually comes at the expense of others. These high-resolution systems will cover cross-track areas {swath w idths) from 12 kilometers {Space Imaging) to 36 kilometers 1WorldView), compared to the broader synoptic swath widths of SPOT (120 kilometers) and Landsat 1185 kilometers).
High-resolution systems are aimed at the mapping, geographic and cartographic mapping markets currently serviced primarily by the aerial photogrammetry industries. Recent studies by the Electronic Industries Association and other firms place the overall r emote sensing business at $4 billion by the year 2000-$1.5 billion of which lies in the space hardware and sensor business. The remaining $2.5 billion is estimated to encompass remote sensing markets, including data and value-added and information product s. Current market estimates place the satellite remote sensing segment (data and products) at approximately $500 million, leaving $1 billion serviced by current airborne systems data, products and services. Some experts believe that the new 1-meter satell ite systems will be hard-pressed to significantly penetrate this large airborne-supported, land-based mapping and cartographic business. On the other hand, Lockheed, E-Systems, Orbital Sciences and others are betting big bucks that they can successfully p enetrate these businesses at a profit. Time will tell, but clearly the explosion of 1-3 meter data promising rapid turnaround delivery time to customers should significantly expand business opportunities for the GIS community.
Two other satellite projects under way are the NASA-sponsored Lewis and Clark satellites, to be launched in 1996. The satellites are being developed by NASA to demonstrate rapid development itwo years) of small satellite technologies at low cost [less tha n $75 million eachl. Lewis will provide hyperspectral {very narrow band) data that will allow much higher discrimination of rock, mineral and soil material. Clark will have three VNIR multispectral bands at 15-meter resolution and one panchromatic band at 3-meter resolution.
Many satellite systems are being built to penetrate and serve new markets for remote sensing data {e.g., prescription farming and digital data production), as well as replace established markets served by existing satellite and airborne remote sensing sys tems (e.g., crop management and 1:12,000and 1 :24,000-scale cartographic mapping). It is questionable how easily or how rapidly the new satellite programs will succeed in developing the markets needed for economic success. A clear path to defining, establ ishing and developing such markets for data from the new systems includes aligning the satellite programs with forward-looking VARs and GIS and information service companies. Such efforts should aim particularly at companies already established in the mar ket segments best served by the new data.
The advent of high-resolution satellite data represents major business opportunities for VARs and GIS and information service companies. A successful route to expanding profitable information markets will belong to companies that recognize the current par adigm shifts in today's resource, manufacturing and other user industries. Such industries have downsized or eliminated internal long-term technology research and development organizations and plan to rely on the marketplace to provide needed information and services. It follows that success should come to the service companies and organizations that actively invest in such long-term research and development applications on behalf of future customers.
Many future commercial users of high-resolution satellite data neither know of these technology developments nor that they will become users of information derived from these platforms. Tactics that may assist satellite platform developers and downstream information service companies in developing these markets include strategic agreements; joint internal research and development of new information packages targeted to market segments; and sound understanding of the content and resolution specifications o f each platform and their relationship to geographic, cartographic and topographic maps.
In any case, with an abundance of new satellite and airborne data, expanding market opportunities and profits await those in the value-added, GIS and information services who chose to work with the new data supliers to invest in developing uses and markets for these exciting new information sources.
GIS World February 1995 vol. 8 No. 2 page 42.