An autofocus algorithm for multi-rotor UAV SAR

Multi-rotor UAV is a popular platform for low-cost SAR system because it has small volume, lightweight and flexible motion. However, due to complicated flight trajectory and low-accuracy motion sensor, autofocus in SAR processing becomes a challenging problem. In consideration of the characteristics of multi-rotor UAV SAR, this paper proposes an autofocus algorithm based on improved Mapdrift technology. The proposed algorithm can estimate the real-time velocity of multi-rotor UAV SAR and compensate the motion error, and then process the signals with range-Doppler algorithm.