Estimation of ground topography under forests with polarimetric SAR interferometry data

This paper presents estimation technique of ground topography in forest areas with Polarimetric SAR Interferometry (PolInSAR) data, and analyses the impact of different directional slops on the topographic phase. On the basis of the Random Volume over Ground (RVoG) scattering model, the complex coherence of the actual experiment PolInSAR data for different polarizations distribute in a region named coherence region. The shape of coherence region mostly are elliptic or triangle in the complex plane. In this paper, by searching the longest axis of coherence region, we fit a straight line. Finally, we retrieve the ground topographic phase and the corresponding topography height by finding the intersection between the fitting line and the unit circle. We test the above procedure with simulated data and airborne data.