Abstract:
Microwave remote sensing is truly the most
rapidly emerging field of satellite remote sensing today.
In a very short span of time, it has found variety of
applications in almost every field which had seen optical
remote sensing dominance. This shows that its both state
of the art and a versatile non-evasive remote sensing
tool. It has added advantage of all-weather availability
and penetration abilities which the optical remote
sensing lacks. Hence can be easily used for areas and
months with dense cloud cover. Of the many applications
of SAR (Synthetic Aperture RADAR) or Microwave
remote sensing is its ability to map and monitor land
surface deformations shown by both natural and manmade features over a period, which helps as an early
warning for many possible disastrous events like
structural failures in dams. The technique involved is
Differential SAR Interferometry or DInSAR. DInSAR
involves a repeat pass configuration of SAR
Interferometry with minimum baseline. The presence of
any random motion on the surface or surface features on
earth, tends to decorrelate the backscatter signals and
add noise to phase difference. Small change due to
surface movements, causes change in phase difference
which is measured precisely and accurately by this
technique. This study aims to measure the deflection that
has come over a period of one year on the walls of
Bhakhra Dam in Himachal Pradesh in India, due to the
change in water levels and pressure exerted by it. Using
DInSAR, the deflection was measured to be around
0.952cm from August 2017 to October 2017.
