Combining dual-band capability and PolInSAR technique for forest ground and canopy estimation

There are basically two methods for retrieving the ground and the canopy height from the interferometric synthetic aperture radar (InSAR) in forested areas. The first method is based on the different dual-band (DB) InSAR height estimation, typically done at X- and P-HH-bands. The second method is based on the modeling of the Polarimetric (Pol) InSAR response of the forest volumetric backscatter, typically at L- or P-band. This paper investigates the possibility of combining both methods, in the sense that the P-band derived ground height is enhanced by the use of the polarimetric data and the RVoG model. In this proposed method, only the ground phase is retrieved from the PolInSAR technique, reducing the numbers of unknowns to be inverted, while the X-band InSAR is used to estimate the canopy. Therefore, we avoid the more complex (and more failure susceptible) inversion of the PolInSAR approach. The data collected in the Amazon region with the OrbiSAR-1 sensor from Bradar (former Orbisat) is used to demonstrate the method. Better ground estimation over range is obtained with the proposed method in comparison with the single-polarization approach for different baselines.