A SEASAT Synthetic Aperture Radar Preprocessor (SARP)

Abstract

A Synthetic Aperture Radar Preprocessor (SARP) for the SEASAT radar is described. The SARP system permits playback of Synthetic Aperture Radar (SAR) data for digital processing into ocean imagery. The system includes a High Data Rate Recorder, SAR Digital Preprocessing (SDP), array processor, mass storage disc, and host computer. Data tapes are played back at reduced rates and the SDP performs the functions of frame synchronization, decommutation of time and status data, presummation of adjacent azimuth returns and correction of gain as a function of range. The data are formatted into presummed range returns and are transferred to the array processor for buffering and subsequent storage on the mass disc. This preprocessing operation loads a 100 x 100 km swath of data on the disc for subsequent range and azimuth correlation to convert the SAR data to imagery. The SAR Data Preprocessor equipment is described and the implementation of the 35 Mbps frame synchronizer and presum arithmetic logic are detailed. A SAR Test Pattern Generator for simulation of SAR and other image data formats is also described. The test generator permits simulation of a wide range of digital data formats (including NASA and IRIG standards) and includes a programmable data pattern capability.