3. The spaceborne SAR system
At the end of 80's, we received a strong
request of national high technology
program. It started our campaign work
on the spaceborne SAR system. IECAS
was arranged as the chief department in
the project and some other institutes
from industry units also take part in the
project. After the significant progresses
of its key techniques, IECAS complete
the design of L-SAR, resulting in
production of the major specification to
meet user's requirement. Hardware
development is advanced. The
instrument comprises two major
functional groups, the central
electronics and an active phased array
antenna, which can be steered in one
axis. IECAS completed L-SAR central
electronics prototype in 1997. It was
developed a demonstration system and
got SAR digital image under the aircraft
tests. In meantime, it is intended to use
for a wide range of possible applied
researches. Fig.2 is its testing result.
China ancient great wall hidden under
dry soil is clearly shown. It was built in
northwest area about 1500 years ago.
Fig. 2 The Yan-Chi Area. Ancient Great Wall Built 1400 Years Before Was Discovered.
The active microstrip patch antenna
model with deployed units will be
verified in near future.
Upon user community's request, the
planned Chinese SAR is designed L
band, HH polarization, changeable
incidence angle and two operating
modes. It will be carried on China made
satellite with a circular sun-synchronized
orbit.
4. SAR Ground Processor
SAR is the combination of coherent
radar and imaging processing technique.
The SAR processor must be designed to
be suitable to the SAR imaging
algorithm and deal with heavy
computation load and high throughput.
The high performance platforms such
as super-PC based processor;
workstation and the array processor are
successfully used for the different user's
requests. The SPECAN algorithm,
Range/Doppler algorithm, Chirp-Scaling
algorithm and their revised
algorithms are developed in SAR
processing for the different operating
modes.
Presently Chinese receiving ground
station is up graded to meet wide users’
requirements in getting microwave
remote sensing data. Activities are now
conducted to get within a reasonable
time the capability to receive signals
from ERS-1/2, Spot, Landsat 7 and
Radarsat. SAR images are widely used
for economic oriented application.
5. The New generation' SAR
Technology
The serial projects of developing new
generation's SAR technology supported
by national high technology program
have been deployed. Latest trends in
SAR system are developing to new
operating modes in order to provide
more and more application.
