A PGA and Time Domain Correlation Based Synthetic Bandwidth Method for High Range Resolution SAR System

Ultra-high spatial resolution is an important development direction of spaceborne synthetic aperture radar (SAR). The finer the resolution, the more details can be obtained from the image. The range resolution mainly depends on the transmit signal bandwidth. However, due to the limitation of the hardware system, the traditional technologies have difficulties in realizing the wide working bandwidth of the radar. Synthetic bandwidth technology is an effective approach to achieving high range resolution. In actual systems, due to differences in hardware and atmospheric transmission characteristics, there are errors in amplitude, phase, and time delay between the received subband signals. Based on the spaceborne SAR multi-subband system model, this paper analyzes the influence of various errors, and proposes a subband splicing method based on phase gradient autofocus (PGA) and time-domain correlation. The simulation results verify the effectiveness of the algorithm.