A novel architecture for multilane-free-flow electronic-toll-collection systems in the millimeter-wave range

An architecture for simultaneously performing multitarget tracking and multidata communication suitable for millimeter-wave multilane-free-flow electronic-toll-collection (ETC) systems is presented. This architecture combines the idea of frequency multiplexing in communication systems and the technique of target tracking in the pulse-Doppler radar. For target tracking, we make use of pulse ranging by the aid of pulse compression and fine target-direction determination by amplitude comparison to obtain high resolution in the radial direction (downrange), as well as both lateral directions (cross ranges). This architecture can be utilized for both active and passive onboard-unit (OBU) systems. Another important advantage of this architecture is that it can easily identify the passing vehicles not equipped with an OBU. This will activate some subsequent enforcement activities against the violation vehicles.