Cyber Attacking Active FMCW Radar Signal AoA Estimation Using Passive FMCW Radar for ADAS Applications

Millimeter-wave (mmWave) radars are a popular choice for Advanced Driver Assistant Systems (ADAS) that identify and track objects in the field of view. These mmWave radars (the primary radar on ego vehicles) are susceptible to interference signals from other mmWave radars (secondary radars on traffic participant vehicles) in the vicinity, which can result in false detection and tracking triggers. Knowing the interference signal's angle of arrival (AoA) is critical for locating the secondary radar source. This study discusses the experiments with AoA estimation of interference signals created by secondary radars when the primary radar is in a passive state. We performed a 3-dimensional Fast Fourier Transform (FFT) on the received I-Q data and used a range-angle heatmap image to determine the signal's spatial pattern. The 3D FFT (range FFT on time-domain ADC samples, velocity FFT on chirps, and angle FFT across antennas) calculates the AoA of the signals. In this experiment, the 77GHz IWR1642 primary radar is in passive mode, while the other 77GHz secondary radars (AWR1642 and AWR2944) are in active mode, providing an interference attack. We also tried with different ranges (2m, 3m, 5m, and 8m) and azimuths to determine the stealthiness of the attack. The AoA for passive radar is a good fit for identifying spurious sources/illuminators of opportunities, electronic counter-countermeasures (ECCM), source localization, knowledge-aided passive radar systems, and cognitive radar development.

I. Introduction

The usage of frequency modulated continuous wave (FMCW) millimeter-wave (mmWave) radars has sky-rocketed in automotive applications like object detection [1], low RCS target detection [2], classification [3], tracking [4], in-cabin health monitoring systems [5], and scene imaging [6], owing to the critical advantage of working in all weather conditions and high measurement precision. The FMCW radars operate in both active and passive modes. The active radar transmits the EM signal and receives it. At the same time, passive radars receive the EM signals present in the propagation environment [7]. These mmWave radars are prone to inband interferences [8] due to the same frequency device community (another mmWave radar operating in the same frequency). This interference caused by another mmWave radar is an electronic countermeasure (ECM), which can cause false detection and track to the primary radar.