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It is worth noting that the new spacebome technology will 
increase user familiarity worldwide with what is now regarded in 
many circles as “exotic” all-weather imaging technology; this 
new familiarity will generate expanded markets for airborne 
SARs. 
The civilian topographic mapping market is estimated to be of the 
order of $2B U.S. per year, and at the present time is based almost 
exclusively on extraction of height information from aerial 
photographs. This market is changing rapidly in response to 
resource development and population growth around the world, 
and in response to increasing concerns about the condition of 
global environments. The market is shifting from programs of 
1:100.000 and 1:250.000 scales to scales of 1:50.000 and larger. 
Improvements are being made to the speed of mapping informa 
tion acquisition, map generation, and geographic information 
integration with other forms of information. STARMAP tech 
nology has allowed airborne radars, with their advantage of rapid 
data acquisition regardless of cloud cover, to enter the mapping 
market, and further technical advances will see that penetration 
increase. Currently planned satellite systems will likely not 
compete effectively here, due to the requirement for highly 
specific, azimuth-viewing geometries, and an increasing require 
ment for very high range resolutions. Hence, it is likely that 
airborne radars will become increasingly important in this niche 
market. 
Environmental monitoring and surveillance is becoming a very 
high priority in the remote sensing community at this time. 
Satellite-bome sensors, including SARS, are well suited to 
routine and inexpensive generation of global information which 
can be used for environmental applications. Satellites are not as 
well suited to surveillance of localized short-term environmental 
emergencies like oil spills, forest fires, earthquakes and floods. 
These applications require flexible sources of information which 
can be controlled and managed by local authorities responsible 
for relief efforts. High resolution information is often required, 
and nearly continuous surveillance is called for in some in 
stances. For these applications, it is likely that satellite and 
aircraft will contribute complementary information. 
Routine maritime surveillance is a third market in which airborne 
radars will continue to play a major role. The monitoring of fish 
eries activities, customs applications, paramilitary operations, 
and the generation of ice reconnaissance information are 
specialized applications where very high resolution (at times 
including visual identification) and real-time data communica 
tion to end users is needed. Because of their flexibility, aircraft 
will continue to be used for these applications. The advent of 
spacebome SAR sensors will allow more efficient use of the 
airborne systems. Regular information from satellites will allow 
the efficient deployment of aircraft to areas of concern. 
Finally, the next decade will see an increasing use of airborne 
SARs for technology development, demonstations, pilot pro 
grams, and technology transfer activities. Spacebome systems 
will be generating operationally useful information within a few 
short years. Plans for operational, rather than exclusively re 
search, use of this information are being implemented, and air 
borne SARs from several countries are centrally involved in 
these programs. As the new satellite SAR information becomes 
more widely used, and as follow-on missions are designed for 
RadarSat, EOS, ERS-1 and 2, JERS-1 and other programs, the 
research requirement for airborne SAR data sets will increase. 
Perhaps the clearest focus on the question of the future of airborne 
SARs is provided by the community of operational users of 
STAR-1 and STAR-2 information. Ice reconnaissance users, for 
instance, require large amounts of information on a regular basis 
for a critically important application which is used to protect 
human lives and a fragile environment in arctic regions. While 
not as dramatic, other surveillance and environmental monitor 
ing applications can be argued to be as “important”, and as 
dependant on reliable information. While satellites will increas 
ingly play a role for these users, they are fundamentally delicate, 
and even unreliable devices. Repair in the event of failure is 
nearly impossible, and a replacement project could cost hundreds 
of millions of dollars and take five years. Operational users recall 
the SEASAT experience of ten years ago, when the promise of a 
program disappeared with the failure of the spacecraft after a 
short 100-day period. 
In the next century, it is conceivable that a network of compatible 
spacebome SARs with shared processing, communication and 
distribution networks will evolve. This evolution would see the 
establishment of spacebome remote sensing systems as, in the 
viewpoint of end users, fundamentally reliable and dependable. 
By that stage they would be viewed in the same way that their 
technological predecessors in space—telecommuncations sys 
tems—are currently viewed. In the meantime, operational users 
will “hedge their bets” by depending upon airborne SAR sys 
tems. 
This paper has provided some specific examples of the use of 
Canadian airborne SAR systems for environmental mapping 
worldwide, and a view to the future for airborne SAR. Those 
applications which hold particular promise for future work 
include sea ice mapping, forest depletion monitoring, soil capa 
bility and land use mapping, environmental emergency support, 
and topographic mapping, particularly in situations where persis 
tent cloud is a problem and where monitoring of rapidly changing 
surface features is critical. 
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