Ghost Image Due to mmWave Radar Interference: Experiment, Mitigation and Leverage

Millimeter wave (mmWave) radar is becoming a major instrument for the ranging, Doppler and imaging of environment in various applications such as autonomous driving and unmanned aerial vehicles. As substantially more radar devices are employed in applications, the interference among different radar transceivers becomes a severe problem, which may bring substantial damages to the applications of radar. One of these impacts is the ghost image caused by the interference, which results in a fake target. In this paper, experiments are carried out to demonstrate the existence of ghost image, based on 77GHz mmWave automobile radar. Detailed analysis is carried out based on the experimental measurements for disclosing the mechanism of interference and the properties of the corresponding ghost image. The prominent features of ghost image include statistically narrow frequency spread, abnormal Doppler estimation and possible negative distance. Based on the these features, systematic approaches are introduced to mitigate the interference induced ghost images. Meanwhile, schemes are proposed to leverage the ghost images for localization and communications, instead of merely removing them.