Radar speed measurement based on doppler principle - includes elimination of angle effect for vehicle on path not parallel to common transmitter line

摘要

To measure the speed of a vehicle more than one Doppler measurement unit is used, whose output Doppler frequencies are combined in a common evaluation device in which the frequencies are converted into corresponding electric signals. Computers are provided in the evaluation device, which realise specified characteristic algorithms using the above electric signals. They evaluate the magnitude of the relative speed its angle and components in certain directions. The velocity in the simple case where the frequencies are the same and have a common wavelength (lamba), is given by V = (lambda) (F) / 4 Cos (beta), Cos (deltasum of the Doppler frequencies, beta is the angle of the equlateral triangle (when beta 1 = beta 2) and delta is the track angle relative to the line joining the two transmitters.