Patent ID: 6583754
Filing Date: 2003-06-24
Classification: G01S

Abstract:
A signal processing method for a vehicle speed sensing system having an RF transceiver coupled to an antenna for transmitting an RF signal towards the terrain over which the vehicle moves and for receiving a reflected Doppler signal therefrom, the transceiver generating a time-domain in-phase reference signal I and a time-domain quadrature signal Q which is offset in phase by 90 degrees from the reference signal I, and a digital signal processor which receives the I and Q signals, the signal processing method comprising:executing a complex fast Fourier transform routine to convert the time domain I and Q signals to frequency domain values I(f) and Q(f); converting the frequency domain values I(f) and Q(f) to a vehicle speed signal; identifying vibration domain frequency values resulting from vehicle vibration; and preventing such vibration frequency domain values from effecting the conversion of the frequency domain values I(f) and Q(f) to the vehicle speed signal.