Improvements to the Stevens drone acoustic detection system

Stevens Institute of Technology (SIT) designed and built multiple acoustic sensors to detect and track drones using Steered-Response Phase Transform (SRP-PHAT) and classify them using narrow-band frequencies. SIT improved a previously built four-microphone system by increasing the number of microphones to seven, modifying the software, and improving the testing algorithm for system performance estimation. The four- and the seven-microphone systems were deployed during several tests conducted with multi-rotor sUAS of different sizes, including the DJI Inspire 2, DJI Mavic 2 Pro, Autel Robotics EVO II Pro, and the Intel Falcon 8 performing flight patterns at various distances, elevations, and speeds. Acoustic signatures were collected and detection distances were compared for the tested drones. Measurements from the field test were used to recalculate UAS acoustic signatures to 1 meter. These signatures were applied to develop a simple method of acoustic detection distance estimation using the passive sonar equation. The improved seven-microphone system provided farther detection distances than the four-microphone system.