Resolution Analysis of Circular Synthetic Aperture Radar Noncoherent Imaging

Circular synthetic aperture radar (CSAR) has attracted much attention in the field of high-resolution SAR imaging. The spatial resolution is usually considered as the most significant parameter for SAR image quality evaluation and has been widely applied for different monostatic/bistatic SAR operation modes. However, it is hard to get an analytical solution to calculate exactly the value of spatial resolution, especially for the circumstance of CSAR noncoherent imaging. In this paper, based on general impulse response function (IRF) of CSAR noncoherent imaging, a method to obtain the quasi-analytical result of the spatial resolution is proposed, which takes the fractional bandwidth and the subaperture angle into consideration. First, the IRF for CSAR is introduced. Second, based on the IRF, the spatial resolution of CSAR noncoherent imaging is derived. Moreover, the half-power beam-width factor is presented, which allows obtaining the form of spatial resolution in an easier way. Finally, the effectiveness of the proposed method is verified with the simulated and experimental CSAR data.