Motion Error Compensation for Quad-rotor Miniature Unmanned Aerial Vehicle SAR Imaging

Abstract

Quad-rotor miniature unmanned aerial vehicle (QMUAV) synthetic aperture radar (SAR) is an ultra-small airborne SAR system. Because of lowing flying altitude and small size constraints, the motion errors of QMUAV-SAR are very complicated which introduces difficulty to the QMUAV-SAR imaging processing. To deal with this problem, an effective motion compensation approach for QMUAV-SAR is proposed. By establishing the relationship between the motion errors and the Doppler parameters of SAR echoes, the motion errors of QMUAV platform are extracted from the estimated Doppler rates. After the majority of the motion error being properly compensated, phase gradient autofocusing (PGA) is employed to estimate and compensate the residual phase errors to further improve the focusing quality of the SAR image. Experimental results are provided and the image quality is evaluated to demonstrate the ability of achieving well focused image and high spacial resolutions of the proposed method.