A millimeter-wave imaging radar in the near field for anti-collision (MIRANDA): RF-DSP integrated architecture

摘要

In order to realize an on-board anti-collision system able to work in any weather condition, a radar imaging system is needed. It must acquire the 3-D radar image of the whole scenario in front of the car with ultra high resolution; furthermore in order to predict the trajectories of the obstacles, the system must acquire their speeds with high accuracy. These requirements cannot be reached, at millimeter frequencies, with phased array techniques; in fact to achieve high accuracy in angularposition, large (in terms of wavelengths) antennas must be used so that the investigation volume falls in the near-field region of the antenna where phased array is unable to image itAt CESPA a project is under development for an imaging radar system for anti-collision, referred to as MIRANDA (millimeter-wave Imaging RAdar in the Near fielD for Anti-collision). This architecture is based on four transmitters and a planar array ofintelligent receiving cells, each one with the microwave front-end integrated with a DSP. These cells are digitally connected in chain by high-speed data links and their millimeter front-ends are coherently synchronized with the transmitted signal. Thereconstruction process is performed in a distributed manner on the DSP net, in order to obtain the images of the observed scenery and the speeds of the obstacles in real-time. This solution requires low complexity millimeter circuits but heavy computation if a conjugate-phase-matched filter is directly implementedIn this paper the integrated architecture of the Radio Frequency front-end will be described