Department of Defence operate separate but similar polar
orbiting meteorological satellite systems, each with two
spacecrafts. Deployment of the new, integrated system will
start around the year 2005. Configuration of its RS payload is
still being designed. It is hoped that in addition to 1km and
4km AVHRR data of the present system, the new system will
have improved data calibration and also record multispectral
data with ground resolution in the 200m - 500m range.
3.3 Landsat 7
Although Landsat 7 is part of EOS (Section 3.1), it is
described separately because of its importance for continuity
of the Landsat series of Earth observations, started in July
1972. Landsat 7 is scheduled for launch in 1998. It will have
an upgraded RS system, the Enhanced Thematic Mapper Plus
(ETM+). RS data will be recorded in 8 spectral bands. Their
ground resolution will range from 15m to 60m: panchromatic
band - 15m, 6 multispectral optical bands (blue, green, red, :
near-IR and 2 mid-IR) - 30m, and the thermal-IR band - 60m.
Global coverage by Landsat 7 RS data will be assured by the
existing dense network of ground receiving stations,
supplemented by onboard data recorders.
3.4 SPOT 4 and S-a & b
SPOT 4 is scheduled for launch in 1997, and SPOT 5-a in
1999. Starting with SPOT 4, their RS payload will include the
Vegetation sensor system. It is of particular interest to global
monitoring, because it will have similar parameters to the
NOAA/AVHRR system: about 1 km ground resolution and 4
spectral bands: blue (experimental), red, near-IR and mid-IR.
Hence, it will be possible to process image data from the
SPOT Vegetation system into 1km NDVI products, important
for global and regional monitoring of vegetation cover. The
main RS sensor system of SPOT 4 will be the High Resolution
Visible and Infrared (HRVIR). It will have 4 spectral bands
(green, red, nea-IR, and mid-IR). Its other parameters will be
identical to the HRV sensor system on-board of SPOTs 1-3.
(Section 2.4). The multispectral system onboard SPOT 5a & b
satellites will have the same spectral bands as the HRVIR
system, but the ground resolution of its data will be 10m in
multispectral mode and 5m in panchromatic mode.
3.5 RADARSAT 2 and 3
Continuity of RADARSAT SAR data is assured, with
RADARSAT 2 fully funded and scheduled for launch by the
year 2000. Inclusion of a global positioning system in its
payload is being considered. RADARSAT 3 has received
funding for its development. A dual-frequency and dual
polarization SAR system, as well as a combination of SAR and
multispectral optical RS system are some of the options being
considered for RADARSAT 3 payload. Its launch is scheduled
by the year 2005.
3.6 Other Planned EO Satellite Systems
The European Space Agency (ESA) and Japan are developing
advanced EO satellite systems. To what extent RS data from
these systems will be used by the regional and global mapping
and monitoring programs will depend on their operational
availability related to such large-area applications, and on the
continuity of coverage by these systems.
418
The European Space Agency (ESA) is developing the Envisat
EO satellite. Its RS systems are being designed for monitoring
of the atmosphere, oceans, ice cover and land natura]
resources. They will include an advanced SAR (C-band, with
dual polarization, HH&VV) and optical multispectral systems.
Envisat is primarily a research-oriented program. It is
scheduled for launch in 1999. Furthermore, ESA and the
European Organization for the Exploitation of Meteorological
Satellites (Eumetsat) are also discussing the possibility of
developing a series of 3 polar-orbiting meteorological
satellites. This latter program is called METOP.
The National Space Development Agency (NASDA) of Japan
also plans to launch two EO satellite series for environmental
monitoring, natural hazards forecasting and land cover
mapping: the Advanced Earth Observing Satellites (ADEOS),
starting in 1999, and the Advanced Land Observing Satellites
(ALOS), starting in 2002. ADEOS sensors are designed for
monitoring the concentration of greenhouse gasses, depletion
of ozone layer, weather conditions, as well as for the mapping
and monitoring of land and oceans. ADEOS-2 will have a RS
payload designed for land cover mapping. Like Envisat, the
ADEOS-2 and ALOS will have SAR and optical systems in
their RS payload. These planned advanced EO systems will
complement EOS. (CEOS, 1995; Osawa, 1995).
4. COORDINATION
BETWEEN THE LAND COVER MAPPING AND
ENVIRONMENTAL MONITORING PROGRAMS
AT REGIONAL AND GLOBAL LEVELS
4.1 Worldwide Selection and Integration of RS data
for Both Types of Programs
Global availability of RS data has been steadily increasing as a
result of growing number of EO satellites, RS sensor systems,
ground receiving stations and improved performance by on-
board RS data recorders. However, selection of the most
appropriate combination of RS data for land cover mapping
and environmental monitoring should be preceded by a
thorough study of users’ information requirements and by
rigorous cost - benefit analysis. The regional and global
programs will typically require RS data with medium and
coarse ground resolution, ranging from 10m to 4km,
depending on particular applications and users information
requirements. Accordingly, the project implementation may be
based on a complete, “wall-to-wall” coverage of the area or on
a sampling design. (Section 5). Alternatively, a two-phase
approach may be adopted for RS coverage, when the complete,
multi-temporal coverage is obtained with coarse RS data, such
as the NOAA/AVHRR data, while the medium resolution
data, such as Landsat, SPOT and/or RADARSAT data, would
be used only in sampling units. Geometric correction of multi-
source RS data and products, their transformation into uniform
cartographic projection and integration with relevant vector
datasets, is a prerequisite for the effective use of RS data in
mapping and monitoring applications. These tasks have been
successfully accomplished (Toutin, 1994).
As it was stated earlier (Section 2.1), a combined analysis of
RS data recorded by optical and SAR systems will yield higher
information content and accuracy of land cover maps and
environmental monitoring products. While the SAR imagery 1S
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996
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