INVERSION OF SYNTHETIC APERTUR,E R,ADAR (SAR) - MSpace ...

4.3 Forward Formulation for SAR Configuration
The plevious section clealtecl with horv the Born inversion can be appliecl
to leflection seismology probler.r.rs. Iu the clerivation, the Boln (first) approximation
used in Eq.(4.9) hacl trvo implicit assurnptions: (a) tlie inciclent
rvavefield renains unafected, ancl (b) only the incidett rvavefield intelacts
rvith the velocity perturbatiol,
The fir'st condition is requirecl to folnulate the Boln invelsion because
the incident wave is assurnecl to be governed by a Green's function for the
constant refelence rneclium in Ec1.(4.10). Thus the transmission losses or
refi'active efects on the incident \¡¿ave as it 1ti'opagates downwalcl ate not
includec{.
The seconcl assumption is in fact the main step of the Born (fit st) apploxirnation
to ornit higher-older scattering caused by other than the incident
'\¡r'ave.
SAR specific features rnust be investigated to develop an invelsion method
of SAR data using tire Born (first) approximation. Differences l¡etween SAR
configulation alcl leflection seismology a;:e summalizecl as follows:
i) unlike in seismic applications, the refelence velocity is a constant, i.e.
the velocity of light,
2) the centel fi'equelcy of tlie ladal signal is rnuch higher than that of
seismic g'aves,
3) the soulce ancl receivel pails ale not ol tlie scatteling sulface, ancl
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