A hovering helicopter has a radar transmitter/receiver for transmitting radar pulses for illuminating a target for SAR imaging, and rotor blades for generating lift. Radar reflectors are on the rotor blades. The radar reflectors are oriented to reflect the radar pulses from the transmitter to the target as the rotor blades rotate. The radar pulses reflected by the moving reflector from the transmitter are timed to generate the synthetic aperture image using radar returns from the target. The receiver also receives blade returns directly reflected from the moving reflectors attached to the lift rotor blades. The receiver analyzes the blade returns to extract motion details of the reflectors and uses the motion details for motion compensation of target returns for SAR imaging.