Patent ID: 7068212
Filing Date: 2006-06-27
Classification: G01S

Abstract:
1. Traffic surveillance radar apparatus having directional sensing and indication capability, comprising: an antenna assembly for (a) transmitting radar waves of given oscillator frequency toward moving traffic targets that are both approaching and receding from said radar apparatus, (b) receiving radar waves reflected from said moving traffic targets, and (c) generating Doppler shifted RF signals representative of said received radar waves; a mixer assembly, comprising first and second mixers with phase shift means coupled between said first and second mixers, for mixing signals having the said oscillator frequency with said Doppler shifted RF signals to respectively produce first and second sets of signals at the outputs of said first and second mixers, said first and second sets of signals including Doppler signals having a frequency equal to the difference between said oscillator frequency and said Doppler shifted RF signals; means for converting said first and second sets of Doppler signals into digital samples; and a digital signal processor programmed to (a) perform a fast Fourier transform on said digital samples, to determine therefrom the speed of selected ones of said moving targets and the direction of travel whether said selected ones of said moving targets are approaching or receding from said radar apparatus, and (b) display the speed of at least one of the selected ones of said moving targets and an indication of the direction of travel of the target having the displayed speed.