Optical Processing of SAR Data

Abstract

The concept of Synthetic Aperture Radar (SAR) is usually credited to Carl Wiley of the Goodyear Aircraft Corporation for his work in the early 1950’s. Groups at both Goodyear and the University of Illinois were pursuing Doppler beam sharpening techniques around this time and an experimental verification of the concept using electronic circuitry was performed by the Illinois group in 1953. The amount of data and the type of processing required for implementing the beam sharpening taxed the capabilities of existing electronic hardware which inspired extensive research into alternate processing techniques. In 1953, a summer group at the University of Michigan (known as project Wolverine) began studying the possibility of using coherent optics for reconstruction of SAR imagery. For the nest three decades, the coherent optics approach was the primary SAR processing technique. Even with todays fast digital processors, optical systems compress a large portion of the collected SAR data. In addition, photographic film provides a reasonably compact medium for storing the immense amount of raw and processed SAR data.