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With RADARSAT's launch on Nov. 4, 1995, Canada and
the world now have access to the first radar satellite system
capable of large scale production and timely delivery of
data. These data will meet the needs of commercial,
government and scientific programs and will provide a new
source of reliable and cost-effective data for environmental
and resource professionals worldwide.
The RADARSAT project, led by the Canadian Space
Agency, builds on the history of achievements in remote
sensing and space technologies by the Canada Centre for
Remote Sensing (CCRS), part of Natural Resources
Canada. With its creation in 1989, the Canadian Space
Agency took over the implementation and operation of the
RADARSAT project as a key component of the Canadian
space program. CCRS continues to participate in the
RADARSAT project through the Radar Data
Development Program (RDDP) and is responsible for data
collection and archiving.
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Satellite Description
RADARSAT, with a planned lifetime of five years, is
equipped with a Synthetic Aperture Radar (SAR). The
SAR is a powerful microwave instrument that can transmit
and receive signals to "see" through clouds, haze, smoke,
and darkness, and obtain high quality images of the Earth in
all weather at any time. This will provide significant
advantages in viewing under conditions that preclude
observation by aircraft optical satellites.
Using a single frequency, C-Band, the RADARSAT SAR
has the unique ability to shape and steer its radar beam
over a 500 kilometre range. Users will have access a
variety of beam selections that can image swath from 35
kilometres to 500 kilometres with resolutions from 10
metres to 100 metres respectively. Incidence angles will
range from less than 20 degrees to more than 50 degrees.
RADARSAT can provide complete global coverage with the flexibility to support specific
requirements. The satellite's orbit is repeated every 24 days. RADARSAT can provide daily
coverage of the Arctic, view any part of Canada within three days, and achieve complete coverage
at equatorial latitudes every six days using a 500 kilometre wide swath.
Example of one day of
RADARSAT SCANSAR Wide
coverage. (500km swath)
Because RADARSAT uses a sun-synchronous orbit, users
can repeatedly view a scene at the same local time.
Moreover, RADARSAT's dawn-dusk orbit places the
satellite's solar arrays in almost continuous sunlight. The major
advantage of this orbit is that the RADARSAT SAR primarily
relies on solar rather than battery power, providing users with
the optimum number of viewing opportunities. Also,
RADARSAT can downlink data to ground stations at a
different time than other remote sensing satellites, most of
which use a mid-morning orbit.
The RADARSAT SAR can capture data for up to 28
minutes and image up to 1.1 million square kilometres of the
Earth's surface with each orbit. In order to serve commercial
and international users, data is downlinked in real time or
stored on one of the two tape recorders until the spacecraft is
within range of a receiving station. To satisfy user
requirements for timely data, the Canadian Data Processing
Facility (CDPF), owned by RSI and located at the Gatineau
satellite station,will deliver data to users within hours of scene
observation.
Data Products
RADARSAT data products will be structured to provide end
users with a choice of resolutions and formats. RADARSAT
will deliver seven standard data products reflecting the SAR
mode options. These will be available in three categories of
geometrical fidelity - quick look, georeferenced, and
geo-coded/ Quick look will consist of the uncorrected SAR
images. Georeferenced products will be geometrically
corrected to compensate for the Earth's curvature.
RADARSAT's geocoded data products will supply precise
positional information to fit standard map projections.
Data will be offered in several formats to suit user needs.
These may include Computer Compatible Tape (CCT), films,
print, and Image Transfer Network (ITN). CD-ROM, 8 mm
tape cartidges and WORM drives will be available as they
become industry standards.
Data Handling and
Distribution RADARSAT data is downlinked in real time to compatible
ground stations. In Canada and the United States, these are
located in Prince Albert, Saskatchewan; Gatineau, Quebec;
and Fairbanks, Alaska. Additional RADARSAT SAR data
reception and processing capability will be added as other
countries with ground stations join the RADARSAT
international data distribution network.
A private corporation, RADARSAT International, Inc.,
(RSI), was established in 1989 to process, market and
distribute RADARSAT data to Canadian commercial users
and to international users. In cooperation with CCRS and
CSA, RSI will help research and develop commercial
applications, and will negotiate foreign reception and
distribution agreements for RADARSAT data. RSI will also
pay royalties to the Canadian Space Agency on the
commercial sales of RADARSAT data.
The Future
The RADARSAT Program continues Canada's tradition of
providing world leadership in advancing Earth observation
technologies and techniques. With its unparalleled operational
flexibility and reliable delivery, RADARSAT will provide high
quality and cost-effective data to researchers and
environmental professionals world-wide.
To sustain RADARSAT's internationally competitive position,
the Canadian Space Agency has prepared a proposal for a
follow-on radar satellite program. This enhanced program is
expected to further exploit RADARSAT's potential for
yielding new environmental and resource information and take
Canada's Earth obervation program into the next millennium.
[LRSGIS]
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