Promoted content: Tracking WiFi Signals to Passively See Through Walls Using NI USRP and LabVIEW

Whether designing healthier cities or grappling with issues such as global health and climate change, the challenges of daily life inspire UCL students and academics. Based at UCL, our team of electrical engineering researchers is investigating passive radar technologies that can see through walls using WiFi radio waves.

Our novel research required a real-time, passive (non-cooperative) wireless target detection demonstration system capable of tracking moving bodies through walls and obstacles. Much like traditional radar systems, our approach still relies on detecting the Doppler shifts in radio waves as they reflect off moving objects. However, unlike traditional radar systems that actively transmit radio waves, our passive system relies on the existing WiFi signals that already swamp our airwaves. The complete lack of spectrum occupation and power emission ensures our radar is undetectable, making it ideal for military or security surveillance in urban settings.

Aside from public defence applications, our passive detection could be applied in a broad range of scenarios, including crowd and traffic monitoring and human-machine interfacing. Different types of wireless signals can be applied to different situations. For example, our system could acquire IEEE 802.11x (b, g, n, ac) signals to detect indoor moving targets for security purposes, such as hostage situations. Alternatively, the same system could monitor cellular signals, such as Global System for Mobile Communications (GSM) or Long-Term Evolution (LTE), to detect direction and velocity of moving vehicles before triggering an appropriate machine response to the detected movement.