| Synthetic aperture radars (SARs) are modern airborne or spaceborne high-resolution imaging systems used in target imaging and terrain mapping applications. SAR systems collect large volumes of complex phase history data that, in some systems, is downlinked to predetermined ground receiving stations for storage and/or subsequent processing. Considering the volume of data generated, SAR phase history data compression techniques are naturally of interest. In this dissertation, three complete SAR phase history data compression systems are presented. Two compression systems are based on trellis coded quantization and can be used to compress phase history data collected by a SAR system, independent of the SAR's mode of operation. The third compression system employs an optimal rate allocation strategy. It is designed specifically for spotlight mode SAR systems and utilizes the fundamental result that a complex image can be formed from spotlight mode SAR phase history data using a (windowed) two-dimensional FFT. Performance evaluations are presented for these compression systems relative to other existing SAR phase history data compression systems. |
