Polarimetric Interferometric SAR: Literature Review and an Assessment of its Utility for DND: TIF Project Memorandum

Polarimetric Interferometric Synthetic Aperture Radar (SAR) is a recent area of research that has had significant attention from the mid-1990s. This area of research has combined the utility of two SAR technologies: Polarimetric SAR (PolSAR) and Interferometric SAR (InSAR). Polarimetric SAR provides four channels which can be used to determine the polarimetric ellipse, and hence, structural information of the scatterer. Therefore PolSAR is suitable for target recognition and detection applications. InSAR data combines two SAR image data sets acquired from nearly the same perspective. The phase difference between these images provides information about the topography, or changes in the topography between the two image dates. InSAR methods have been used to map terrains, detect environmental changes and determine velocities of moving targets. By combining both technologies, polarimetric InSAR (Pol InSAR) permits distinction between different distributed targets at different elevations. In particular, most current research is investigating use of this technology for measuring the height of forest, and to help estimate its biomass. Other applications under research include terrain moisture estimation, terrain roughness estimation, and (of more interest in mapping applications) vertical obstruction detection.