Subrata Kumar Das , pp. 45. ING/School of Engineering, 2010.
Synthetic Aperture Radar (SAR) is an important tool for remote sensing now a day. SAR
image quality measurements play an important role in the development of SAR image digital
processing methods. The essential SAR image quality assessments are spatial resolutions,
Integrated Sidelobe Ratio (ISLR) and Peak Sidelobe Ratio (PSLR). This thesis mainly focuses
on the UWB SAR image quality measurements. Since the spatial resolutions depend on
integration angle in UWB SAR, measurements should be performed at different integration
angles for a UWB SAR system. Evaluation or comparison of the resolutions obtained with
different UWB SAR systems can be based on another measurement named differential
resolution measurements. For ISLR and PSLR measurements, it is seen that elliptical areas
are more suitable for delimitation of mainlobe and sidelobe areas of a UWB SAR image than
rectangular areas. This is proved by an investigation relied on a newly derived Impulse
Response Function in SAR Imaging (IRF-SAR) instead of the widely used sinc function.
From this investigation, we can also see that a factor of 2.5 is sufficient to represent the
spread of mainlobe in both azimuth and range direction.
In this work, we use simulated UWB-low frequency CARABAS-II data. The simulations are
performed in Matlab. In spite of the main drawback in computational cost, Global
Backprojection (GBP) algorithm is still selected for UWB SAR image formation due to its
time-domain characteristics such as extreme range migration handling, manageable motion
Subrata Kumar Das
Deputy Regional Engineer, Bangladesh Betar,
Link Road, Cox's Bazar