Propeller Modulation Equalization via Reference Tones

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.