  Propeller modulation, also known as micro-Doppler modulation, presents a
significant challenge in radio frequency (RF) inspection operations conducted
via drones. This paper investigates the equalization of propeller modulation
effects on RF signals, specifically targeting applications in navigation aids
such as Instrument Landing Systems (ILS). By employing a continuous reference
tone, the propeller-induced Doppler spread can be effectively captured and
equalized, improving signal integrity and accuracy. Simulation results
demonstrate that the proposed equalization method significantly reduces DDM
deviation caused by propeller modulation, even under various propeller speeds.
The findings suggest that incorporating such equalization techniques can
enhance the reliability and efficiency of drone-based RF inspections.
