International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part Bl. Istanbul 2004
pixels pairs). This error also identified during pre-flight tests
was easily corrected
5. ALSAT-1 CARACTERISTICS
Damietta
Alsat-1 has three major characteristics, which distinguish it
from the other microsatellites. We tried during this first year of
satellite operations to put them in evidence.
5.1 Wide swath width
; or ; ; ie Cairo
The main characteristic of Alsa-1 is to achieve a daily revisit in
conjunction with the other satellite of the constellation. Hence,
a large FOV was implemented. Several full size images were
taken as this one taken on September 2003, the 28th, in the
North-East of Algeria. It shows the exceptional big size
allowing to cover 33.6 million hectares. This shows the
importance of the area that can be covered: 10 images are
enough to cover the hole of Algeria with its 238174 1km’.
1088km
Figure 6: Alsat-1 image of Chott Merghir (Algeria)
taken on 28 Sep. 2003 © CNTS 2003
5.2 Windowing
This function was added during the design of the satellite to
avoid a saturation of the storage units and add more flexibility
during the satellite operation. Alsat-1 being an experimental
satellite, this function should allow us to image various types of
area (around the world). This characteristic was able to be
exploited to take images of an exceptional size.
We can see on the photo 7 the example of an image taken with
bank! (half Alsat-1 capacity) on the entire Nile River in one
pass (from the Nasser lake to the mouth of the Nile on the
Mediterranean Sea): a total image size of 160x1088 km. We
could double the swath using both banks simultaneously.
Aswan
5.3 Short Revisit time
The exceptional swath width of Alsat-1 allows obtaining a
particularly short pseudo period (for a satellite not equipped v
os ne i AE Las AE Figure 7: Alsat-1 image of the Nil River (Egypt)
i saa DNS E: eus taken on 19 Oct 2003 O CNTS 2003
quickly react during the start of a fire.
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