Dr. Defender: Proactive Detection of Autopilot Drones Based on CSI

The market for consumer drones is growing and drones are becoming ever more pervasive than before in our life. However, drones have also brought about severe privacy violations and even safety issues. Especially, drones with cameras can snap pictures or take private videos. Researchers have designed drone detection mechanisms by passively inspecting the radio frequency (RF) signal in the communication channel between a drone and its controller. However, passive detection solutions shall fail when drones are in autopilot mode without control signals from controllers. In this paper, we seek to detect autopilot drones that transmit no RF signals by developing a proactive detection system named Dr. Defender. To this end, we resort to the Wi-Fi signals prevalent at each house and propose a proactive drone detection mechanism. To facilitate the detection of drones with Wi-Fi, we first study the motion characteristics of drones, including the shifting, moving, and spinning of propellers that can uniquely represent a drone. Then we investigate the physical layer information of Wi-Fi signals, i.e., the channel state information (CSI), to reveal specific motions of a drone. Finally, we implement our CSI-based proactive drone detection system, which requires no signal transmission from a drone or its controller. We extensively validate the feasibility and performance of our solution under different distances and directions of drones relative to a window. Results show that Dr. Defender can accurately detect drones 10 meters away.