Robust detection and mitigation of mutual interference in automotive radar

Active safety functions are being integrated into more and more cars. Many of these rely on radar sensors as a source of information about surrounding objects. Based on this information, for example, emergency braking maneuvers are initiated. This requires a very high reliability of the provided data. In the long term, these requirements will become even stricter as highly automated driving comes into play. In the near future, this will result in a high density of radar sensors operating simultaneously and in close proximity. This constellation generates mutual car-to-car interference if no precautions are taken. At present, efforts in measures to mitigate the interference concentrate on time-frequency signal processing. Spatial filtering using digital beamforming is another powerful method. This paper aims to cover the chain of interference, from the basic principles of waveform interaction in a radar sensor's receiver stage, up to mitigation techniques and consequences for signal processing in the presence of interference.