Quantification of noise levels for the flying drones in accordance with operating condition

This study investigated quantification method of drone noise levels according to various operating conditions through the field measurements. In South Korea, a pilot credential is mandatorily required to operate a drone more than 250 g in accordance with the Aviation Safety Act. Pilot credentials are divided into 4 levels, and Type 1 credential is the highest grade for covering drones of 25 kg to 150 kg which are high-risk unmanned aerial vehicles. For the pilot credential test, a standard flight pattern is defined with various operating conditions such as taking-off, landing, hovering, cruise, triangular and circumferential flights. Accordingly, the environmental noise characteristics according to the standard flight pattern were measured for two types of drones. The measurements are carried out at three points which are 5 m apart from the center of the basic operational range, and one point which is 2 m apart from the center of the route passing-by during the cruise operation. As results, the appropriate evaluation indicators and measurement points were suggested by each operating condition. In addition, repeatability and reproducibility of the measurement results were discussed, and the relationship with environmental noise standards was reviewed.