Bistatic Doppler radar for vehicle speed determination

A monostatic Doppler radar can yield accurate vehicle speed measurements over a very limited angular extent. When applied to a multi-lane super-highway geometry, the area within which the vehicle must be confined for accurate measurement becomes quite small. A much larger areal extent for accurate measurement can be achieved by designing the radar system for bistatic operation. In this geometry the transmitter and receiver are on opposite sides of the multi-lane highway and both transmitting and receiving antenna beams are oriented towards the vehicle. A radiation leakage link is required between transmitter and receiver to provide a reference frequency signal. Examples are given to show the operational advantage of a bistatic radar compared to a monostatic radar.