Cover Chirp Jamming: Hybrid Jamming--Deception Attack on FMCW Radar and Its Countermeasure

The reliability of measurements is crucial for ensuring the safety of control systems that depend on such measurements. Frequency-modulated continuous-wave (FMCW) radar is an active sensor used to measure distance and speed. Security evaluations of commercial FMCW radars have focused primarily on deception attacks, assuming that jamming attacks are easier to address. In this study, we propose a novel and efficient jamming attack called cover chirp jamming. This attack utilizes deception techniques and concentrates energy near the target, resulting in higher efficiency compared to conventional jamming methods. Furthermore, it can bypass existing countermeasures against noise, interference, and jamming. We demonstrate the effectiveness and feasibility of the attack through field and simulation experiments using a modern 77-GHz multi-input multi-output FMCW radar. Moreover, we propose a software-based countermeasure that detects and mitigates the attack. Our quantitative evaluation shows that the power of cover chirp jamming is 17.4 dB higher than conventional jamming. In addition, the countermeasure effectively mitigates the attack if the jamming-to-signal ratio (JSR) is below 0.6 dB, whereas the cover chirp jamming cannot be mitigated when the JSR exceeds 0.6 dB.