Uwb Foliage Penetrating SAR Imaging Algorithms

Synthetic aperture radar (SAR) provides a wide range of applications in remote sensing in which ground imaging is of interest to both military and civilian end users. Imaged scene size depends strongly on swath or antenna beamwidth in elevation while the imaging resolutions of a SAR system are functions of radar system bandwidth and antenna beamwidth. In this context, SAR systems could be divided into two groups: narrow band and narrow beam (NB) SAR, and ultra wideband and ultra wide beam (UWB) SAR . The concept of ultra wide band can be interpreted either by large absolute bandwidth or large fractional bandwidth. Similarly ultra wide beam, can be seen either by wide antenna beamwidth or associated with wide integration angle (time) in processing. Hence an UWB SAR system, which utilizes a large fractional bandwidth signal and a wide antenna beam width enables large imaged scene and/or high resolution imaging.This thesis looks at the problem of image formation of an UWB SAR system. Different SAR imaging algorithms in both time and frequency domain and their suitability to process UWB SAR data are investigated and evaluated. Three wave reconstruction algorithms based on the matched filter imaging equation are presented and simulated. They demonstrate different levels of performance and accuracy, which will determine their practical use. A fourth algorithm known as backprojection is then presented to provide comparative quality with the best wave reconstruction algorithm with a reduced computational load. The time domain imaging algorithms are highly recommended for UWB SAR data processing due to their characteristics, such that their capabilities to handle motion compensation, unlimited scene size and local processing.An along track monopulse SAR system simulation is then presented to investigate its capability of detecting moving targets embedded in foliage from the monostatic and bistatic SAR data signals.