Civil, Commercial, and International Remote Sensing Systems and Geoprocessing
David L. Glackin and Gerard R. Peltzer
Chapter 1: Civil, Commercial, and International Remote Sensing (cont.)
1.4 Key Trends for the Coming Decade
1.4.1 Introduction
The coming decade will witness a transition of Earth remote sensing from a field that is dominated by large, complex, expensive civil governmental and military systems to one that includes an increasing amount of purely commercial systems (Fig. 1.8), hybrid government/commercial systems (Fig. 1.9), systems from commercial/university consortia, focused missions using small satellites, multiple-use systems, and systems of lower complexity and cost. We are moving away from an era in which spaceborne remote sensing systems are driven solely by scientific, military, and operational weather requirements, to an era in which the market value of the end-user products will play an increasing role in determining which systems are flown. There will still be scientific, military, and operational weather satellites launched throughout the decade, but added to the mix will be an increasing trend toward commercialization, designed to recoup a greater portion of the initial investment in the systems. As budgets become increasingly constrained, these trends can only be expected to accelerate.
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Fig. 1.8. Fully commercial and private systems (excluding microsats), 1997–2002. |
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Fig. 1.9. Government/commercial hybrid systems, 1980–2007. |
In order to assist commercial companies to reduce their risk in entering the field, "anchor tenant" relationships are developing in the United States between government and commercial companies, especially those building the high-resolution systems. In these relationships, the government promises to buy a certain amount of data from the companies, so that they have some minimum guaranteed income. These types of relationships may become increasingly common worldwide as more countries enter the commercial marketplace. In the United States, it is likely that more commercial licenses will be applied for and granted.
As governments attempt to hand off more of the responsibility for remote sensing systems to industry, more hybrid government/commercial systems may be seen, in which the government asks industry to share in the up-front costs of developing a new system. Along the same lines, it can be expected that governments will have an increasing interest in allowing industry to have complete responsibility for system procurement, launch, and operations, after which the government will simply purchase the data from the industrial partner (the "data buy" approach).
According to current plan, by 2000, 17 countries will own or will have owned free-flying Earth remote sensing satellite systems over 100 kg (plus 5 more if the ~50-kg microsatellites from Chile, Malaysia, Pakistan, Portugal and South Africa are included). Beyond 2000, Australia and Spain intend to join this group (Fig. 1.1). This proliferation is resulting in forces stemming in part from a desire to develop an indigenous capability to build spaceborne remote sensing hardware, in part from national pride, and in part for reasons of technology transfer. According to current plans, countries contributing to this international proliferation will be Argentina, Australia, Brazil, Germany, Israel, Italy, South Korea, Spain, Taiwan, and Thailand. As pointed out previously, many of these countries will be using the technological services of other countries to build the remote sensing hardware, while personnel from the two countries work to transfer technological expertise. In many cases, countries will team up, as indicated in Table 1.5.
Table 1.5. Satellites over 100 kg with Multiple Operators/Builders (1998–2007)
| Operator | Program | Satellite builder | Instrument builder | Comments |
|---|---|---|---|---|
| Australia | ARIES | To be defined | Australia | — |
| Brazil/China | CBERS | China/Brazil | China | — |
| Brazil/Malaysia | Amazon | To be defined | To be defined | — |
| Brazil/Holland | FAME | To be defined | To be defined | Conceptual |
| China | L-SAR | Canada | Canada | Conceptual |
| Israel/Germany | David | Germany | Israel | — |
| Israel/USA | EROS | Israel | Israel | — |
| South Korea | KOMPSAT | USA | USA | — |
| Taiwan | ROCSAT | USA | Taiwan | — |
| Thailand | TRSSS | Canada | To be defined | — |
| Ukraine | SICH-2 | Russia | Russia | — |
This proliferation of international capability will lead to a potential for cooperation or competition, which could ultimately affect the commercial marketplace as more countries develop their own advanced capabilities. There will clearly be an increasing need for international coordination, which today is provided on a mostly unofficial basis by the Committee on Earth Observation Satellites (CEOS). This is a body whose members work primarily on a voluntary basis to help coordinate the remote sensing plans of various countries. CEOS has met with some impressive success. However, a more official institutionalization of CEOS, with the associated funding, may be required for CEOS to effectively handle the field as it grows and doubles in regard to the number of participating countries.
While new countries join the remote sensing community, the fiscal crisis in the former Soviet Union seems only to be worsening. It is expected that Russia and the Ukraine may have an increasingly difficult time during the coming decade in maintaining a comprehensive Earth remote sensing program.
A trend toward special-purpose remote sensing systems is expected over the next decade (Fig. 1.10). Present systems tend to be designed to serve multiple user communities. In the future, an increasing mix of systems aimed at specific applications areas and user communities is expected. Examples include ocean color (OrbView-2/SeaStar), precision farming (Resource21 and GEROS), fire monitoring (FIRES), mining (ARIES), and the high-resolution market (Ikonos, QuickBird, OrbView, and EROS). Systems designed for geographically regional studies include Brazil (SSR), South Korea (KOMPSAT), Taiwan (ROCSAT), and the Mediterranean (COSMO/Skymed and COALAS). In addition, several microsats focused on technology transition are and will be flying.
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Fig. 1.10. Trend toward specialized applications. |
1.4.2 High-Resolution Commercial Systems
As the commercial benefits of the high-resolution "1-m" systems begin to be widely known, the international proliferation of such systems may occur. These systems will improve a host of applications, including mapping, urban planning, disaster assessment for insurance companies, pipeline/power line monitoring, communications equipment siting, news reporting, and real estate. The spatial resolutions of these systems could continue to drop below 1 m, as they have already done in two 0.8-m systems (Fig. 1.11). It is not clear how cost-effective significantly higher resolution systems could be in the marketplace, although there is already discussion of 0.5-m systems. There are trade-offs between resolution, ground coverage, data rate, and data storage volume, which need to be carefully considered.
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Fig. 1.11. Spatial resolution versus time, electro-optical systems, 1980–2007. |
These high-resolution spaceborne systems will complement airborne imagery and may displace some fraction of the existing market for airborne imagery. The size of that fraction will determine the commercial viability of these systems over the coming decade. It can be anticipated that the mere existence of the new spaceborne systems might cause the marketplace to expand, which could leave more room for growth for everyone. The chief executive officer (CEO) of one of the companies that plans to field a 1-m system has stated that the insurance industry alone may be able to support one such system.
The topographic capabilities of these systems when coupled with GIS will be powerful. The ability of the systems to generate DEMs using in-track stereo observing techniques (or interferometry in the case of SAR) will prove over the coming decade to be very useful. The DEMs will help in mapping, road route selection, communications equipment siting, disaster response, news "fly-throughs," and even in the visualization of real estate, with its potential associated problems of mud slides or flooding on a given piece of property. In many cases, 3- to 5-m resolution may suffice, while in other cases, 1-m resolution will be required.
Currently, the spatial resolution of spaceborne imaging systems is lower than that of airborne systems. It is expected that the 1-m systems will result in a growth of the community that uses space-based data for mapping purposes. This, in turn, should fuel a growth in the use of GIS software. The issue of the geolocation accuracy of the space-based imagery with respect to ground coordinates will be an important concern. This need for accuracy is expected to translate into a need for improved star trackers, pointing gimbals, and GPS receivers onboard the satellites. The need for improved components represents an area of potential commercial opportunity, particularly because such components are currently costly.
1.4.3 Revisit Time
A large cross section of the user community requires frequent imaging revisits of the same area on the Earth. During 1998 to 2007, the capability of electro-optical space-based remote sensing systems to reimage a given area within a short amount of time will significantly improve for systems across the full range of spatial resolutions (Fig. 1.12). In this publication, revisit time is defined as the average elapsed time between imagery of a given location at the Earth's equator, which for polar sun-synchronous orbits represents the most stressing case.
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Fig. 1.12. Sensor revisit time versus spatial resolution, 1980–2007. |
Revisit times are for a single instrument or sensor onboard the satellite, and they are lower (i.e., better) when the instrument can gimbal perpendicular to the travel direction of the satellite. A well-known example of an instrument that cannot gimbal is the Thematic Mapper onboard Landsats 4 and 5. The Thematic Mapper, with a swath width of 185 km, requires 16 days to "paint" the Earth and begin to repeat coverage. The SPOT system, on the other hand, can gimbal, resulting in far better revisit times. Such a capability will become commonplace in the next decade. It should also be noted that the revisit time for a constellation of satellites is better than that for a single satellite, hence the plethora of plans for multiple-satellite constellations (e.g., Resource21, GEROS, and EROS).
1.4.4 Hyperspectral Imaging
During the 1998–2007 period, the number of spectral bands in many space-based electro-optical imaging systems will increase dramatically (Fig. 1.3). The upper limit for multispectral imagery will double from 18 on the Indian IRS-P3 to 36 in the Earth Observing System's MODIS instrument. Hyperspectral imagers with an order of magnitude more spectral bands will be introduced to space near the beginning of this period. It can be expected that more spaceborne hyperspectral missions from around the globe will be added as the OrbView-4 program investigates the commercial utility of dual-use hyperspectral imagery, as the NMP demonstrates the technology while flying multispectral and hyperspectral instruments side by side, and as the ARIES program investigates practical mining applications. These systems are expected to enable widespread improvements in applications such as oil and mineral exploration, precision farming, crop assessment, and forestry.
At the same time, many electro-optical imaging systems will be flown in this period that have a total number of spectral bands well below 10. These systems consist partly of the commercial high-resolution remote sensing satellites, for which high spatial resolution is more important than a high number of spectral bands. Implementing both features simultaneously would drive the data rates for these systems to very high levels.
1.4.5 Ocean Color
Ocean color imagery will become more widely available to the commercial industry over the coming decade, as the OrbView-2/SeaStar satellite continues operation and as the color imagery capability proliferates internationally (Fig. 1.5). It can be expected that the utility of these ocean imagery data to the world's fishing fleets will be intensively evaluated over the coming decade, and that more systems may be planned and launched as a result.
If the concept of a governmental "data buy" proves to be viable, then this approach may become more widely used over the next decade. This approach would generate commercial opportunities in supplying end-to-end remote sensing services, in which the commercial prime contractor would be responsible for procuring the satellite bus, the sensors, and all of the subsystems; launching the satellite; providing command, control, and tracking facilities; downlinking the data; processing and analyzing the data; and performing quality control. The data buy approach may become more popular if industry can demonstrate an ability to maintain quality control, which currently typically requires the oversight capabilities of multidisciplinary government review teams.
1.4.6 Precision Farming
Precision farming, and the support of high-value agriculture by remote sensing, is seen to be an increasing trend over the next decade. For example, in 2000, two systems are scheduled to be launched: GEROS (GER Earth Resource Observation System), from Geophysical & Environmental Research Corporation in New York state, and Resource21, from a consortium of Boeing, GDE Systems (recently purchased by GEC Marconi), and agribusiness firms. Both of these systems will employ 10-m multispectral imagery to monitor the condition of crops with respect to fertilization, watering, and disease. Additionally, GEROS will have a sharper panchromatic band. These systems will improve upon the SPOT 20-m and Landsat 30-m multispectral data that are currently used. Precision farming is likely to be a solid market with excellent growth potential over the coming decade.
1.4.7 SAR and Lidar
The evolution of SAR imagery over the next decade is more difficult to predict. Looking at the planned and proposed missions during this period, a much more measured approach is seen (Fig. 1.6). This measured approach is partly because of the relative difficulty of building a SAR system, partly because of the difficulty of interpreting SAR imagery, and partly because of the uncertainty of the market for SAR data.
The countries proposing to enter the field of SAR remote sensing include China, India, and Italy. Canada, ESA, and Japan will continue to fly scientific and commercial SAR systems, while the plans of the former Soviet Union are less clear. The fiscal problems in Russia and the Ukraine are only expected to get worse before they get better. The LightSAR system from the United States is dependent upon cost-sharing from industry, but appears to be moving ahead, while the Shuttle Radar Topography Mission (SRTM) has encountered recurring funding difficulties, but is due for launch in 1999. A recent entry in this arena is Research and Development Laboratories (RDL), with the commercial Radar-1 mission.
In the area of active electro-optical sensing with spaceborne lidar, several missions are planned. First, NASA's Earth Observing System Laser Alt-1 mission, recently renamed ICESat, will host a laser altimeter, principally for measuring ice sheet topography. Second, it was recently announced that a NASA Earth System Science Pathfinder (ESSP) mission will be PICASSO-CENA, a joint mission between NASA and the Institut Pierre Simon Laplace in Paris. A backscatter lidar for measuring clouds and aerosols will be hosted on PICASSO-CENA. These two missions are slated to fly in 2001 and 2003, respectively. Third, NASA's New Millennium Program Earth Orbiter-2 (NMP EO-2) will host the Space Readiness Coherent Lidar Experiment (SPARCLE). This is a coherent Doppler wind lidar, designed to investigate the feasibility of measuring the atmospheric wind profile from space. This measurement has represented an ambitious goal of space-based lidar research for at least two decades. Fourth, ESA is studying the possibility of using a Doppler wind lidar called ALADIN for its Earth Explorer Atmospheric Dynamics mission, which at last report was No. 2 priority among the four Earth Explorer missions under consideration for flights beginning in 2003.
1.4.8 Small Satellites and Instruments
The use of small satellites of the minisat class (100–500 kg) for remote sensing is expected to accelerate over the coming decade (Fig. 1.2), partly because of fiscal considerations. As the number of countries fielding remote sensing satellites proliferates, more minisats are scheduled for launch, and more can be expected to follow. Because launch costs are a substantial fraction of total mission costs, and because it is far less expensive to launch a minisat than a heavier satellite, minisats are expected to become increasingly popular as fiscal pressures mount. Commercial opportunities may exist for new multipurpose minisat buses that control costs through the maximization of modularity and commonality in their design.
During the 1998–2007 period, a number of small satellites of the microsat class (10–100 kg) are scheduled to be launched, mostly by countries that are just getting started in space-based remote sensing (Table 1.4). The countries that have prior experience with microsats (e.g., South Korea) are tending to launch heavier ones over time. Although a trend is just starting to be seen among the most experienced countries toward significant downsizing of remote sensing instrumentation, this very advanced technology is not expected to be adopted by the nations that are still developing their initial capabilities during this period. In addition, it is expected that these nations will fly more instruments on minisats.
Coupled with the trend toward more small satellites, especially in the minisat class, will be a desire for downsized but highly capable remote sensing instrumentation, at least among the more experienced nations. Following the research oriented demonstration of such instruments by means such as the New Millennium Program, a commercial market may develop for such instruments. Smaller, lighter instruments mean smaller, lighter satellite buses to support them, which means smaller launch vehicles, all equating to lower cost. A trend in this direction can be expected over the next decade.
It is much more difficult to predict the impact of nanotechnology and MEMS in remote sensing over the next decade. As discussed above, developments in these fields, as well as in application specific integrated circuits (ASIC), could be used to develop miniaturized instrument "back-end" components such as signal electronics and onboard data storage devices, not to mention complete nanosatellites realized in silicon. Because nanotechnology and MEMS remain in their infancy, attempts to predict their impact over the coming decade are premature.
1.4.9 Large Satellites
In 1999, Europe's heaviest remote sensing satellite to date will be Envisat, at 8000 kg, and Japan's heaviest remote sensing satellite to date will be ADEOS-2, at 3860 kg (Fig. 1.13). France's SPOT satellites will also be getting increasingly massive, from the 1800 kg SPOT-3 in 1993 to the 3000 kg SPOT-5 in 2002. This observation ignores Russian satellites, which historically have been very massive (e.g., Almaz-1a at 18,000 kg). Further increases on the high end of the mass scale are generally not expected, however, as fiscal realities have their effect.
Fig. 1.13. Representative medium and large satellites for Earth observation, 1990–2007. |
1.4.10 Unmanned Airborne Vehicles
Reliable high-altitude unmanned airborne vehicles (UAV) are under development to support scientific remote sensing missions. Leading examples are the Pathfinder vehicle from AeroVironment, Inc., and the Theseus vehicle from Aurora Flight Sciences Corporation. UAVs could fill a niche between aircraft and satellite remote sensing. Commercial applications for such vehicles may be identified and exploited in the future as their performance improves and their capabilities become more widely known. The potential for cost savings with respect to satellites is great.
1.4.11 Conclusions
The trends that only started in 1998 (Table 1.6) will reshape the face of Earth remote sensing by 2007. By that time, we should know the impact of all the trends discussed in this section. The field will be significantly influenced by the international proliferation of remote sensing, as well as its increasing commercialization, the greater number of high-resolution systems, the increasing application of small satellites and lightweight instruments, the proliferation of SAR, and the increasing number of hyperspectral systems. Also, lest we not forget, there will be a continuing need for trained scientists and engineers who can understand the systems end-to-end and ensure the continuing health of the burgeoning field of Earth remote sensing for many years to come.
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