Iteratively compensating for multiple scattering in SAR imaging

The Born approximation is a common approach taken in modeling the physics of SAR imaging. In essence it says that radiation only scatters once when in space. This is a reasonable assumption for targets that lie far apart or that are far from the transmit and receive antennas, but it introduces error into the imaging process. The goal of this paper is to iteratively compensate for this error by using estimates of the target distribution to estimate multiple scattering phenomena. We will use a noise reduction technique at each iteration on the corrected data as well as the estimated image to control any excess error caused by the estimated multiple scattering phenomena. The physical model for our work will be based on the wave equation. We will briefly derive the important features of the model as well as account for the error brought by common approximations that are made. Typically one does not get an image that is approximately the target distribution, but rather an image that is approximately proportional to the target distribution. This means that there is a scaling parameter that must be chosen when using target distribution estimates to correct data. We will discuss methods for choosing this parameter. We will provide a few basic SAR imaging methods and perform simulation using the Gotcha Data set in combination with the iterative technique. At the end of the paper we will outline future work involving this method.