A Novel Motion Compensation Framework for Micro UAV FMCW SAR

Micro UAV gives easily rise to motion error with low amplitude and high frequency. In Micro UAV SAR imaging, the motion error is always 2-D space variant. The high frequency motion error with 2-D space variant property challenges the traditional compensation algorithms. The existing RCBC algorithm can compensate the range-variant motion error effectively for FMCW system. However, its efficiency is very low and only azimuth-invariant error is taken into account. This paper analyzes the imaging characteristics of FMCW SAR and establishes a novel compensation framework for high frequency motion error with 2-D space variant property. The framework first simplifies the “Range cell-by-cell” algorithm using local space invariance of error to obtain the RBBC algorithm. Subsequently, we introduce the traditional FDA to compensate the AVPE, which is ignored in RCBC. Finally, the simulation experiments are conducted to verify the effectiveness of the proposed compensation framework.