Spotlight SAR Imaging with Sufficient Cyclic Prefix-OFDM Waveform
Gaurav Sharma, Arockia Bazil Raj
Abstract
This paper investigates the orthogonal frequency-division multiplexing (OFDM) based Spotlight synthetic aperture radar (SAR). For performing Inter range cell interference (IRCl)-free in SAR imaging, OFDM pulse with Cyclic Prefix (CP) can be used. However, IRCI-free imaging is achieved only by adding sufficient CP at beginning of each OFDM block i.e. length of CP greater than or equal to the swath width. Spotlight SAR due to its geometry experiences variable swath width hence requires evaluation of optimum CP length for desired results. Also, the removal of CP from received signal requires implementation of precise range gating to avoid distortion. This paper proposes imaging algorithm for spotlight SAR imaging with sufficient CP-OFDM waveform. Simulation results present improvement in the image resolution in comparison to linear frequency modulated (LFM) waveform by the proposed algorithm for spotlight SAR.