Lyons and Sandwell, JGR, 2003

LandersEQ

Hector MineEQ

http://topex.ucsd.edu/gmtsar

forming interferogram

B = Bsin θ −α( )

B⊥ = Bcos θ −α( )

∂φ∂ρ

=−4πBλρ

cos θ −α( )sinθ

cosθ − ρb

)*+

,-.

φ − φe( ) ≅ −4πreBcos θ −α( )λρbsinθ

(r − re )

phase due to curved earth

phase due to topography

Perpendicular baseline MATTERS!

total phase

Phase from curved Earth

total phase

Critical Baseline

Phase from topography

phase minus spherical earth

How high is Toro Peak?

deformation and topography

Lyons and Sandwell, JGR, 2003

LandersEQ

Hector MineEQ

Triggered slip on Southern San Andreas Fault

Need for Precise Orbits1.  proper focus

2.  transform from geographic radar coordinates

3.  image alignment

4.  flattening interferogram

Brute force algorithm given precise orbit subroutine pick target point fly satellite along orbit and identify point of closest approach(This is inefficient but computers are fast so don’t waste time coding.)

GMTSAR

2-pass processingno ground controlseamless abutment of frames along track

stacking for time seriesone master and many slavesprimary, secondary, tertiary, image alignment

ScanSAR Interferometrypossible but not easycode needs refinement