Patent ID: 7474259

Claim:
A vehicular traffic sensor for mounting at a fixed location to monitor multiple lanes of traffic, the vehicular traffic sensor comprising: a processor unit for generating a programmable time-varying frequency modulating signal; a transceiver unit for receiving the programmable time-varying frequency modulating signal from the processor unit and for generating a linear frequency modulated microwave signal based on the programmable time-varying frequency modulating signal; at least one antenna for (i) receiving the linear frequency modulated microwave signal from the transceiver unit, (ii) forming a radiation beam, (iii) radiating the linear frequency modulated microwave signal in the radiation beam at an object; and, (iv) receiving the modulated microwave signal reflected back from the object; and a signal stabilizing unit for receiving a portion of the linear frequency modulated microwave signal from the transceiver unit and for providing a proportional calibration signal back to the processor; wherein the processor unit is further operable to (i) receive the calibration signal from the signal stabilizing unit, (ii) measure frequency parameters of the calibration signal, and (iii) correct the programmable time-varying frequency modulating signal based on the frequency parameters of the calibration signal to increase the linearity of the modulated microwave signal; and the processor comprises a curve-fitting module for determining an inverse non-linear function from the frequency parameters of the calibration signal, the processor unit being operable to generate the programmable time-varying frequency modulating signal based on the inverse non-linear function to compensate for distortion introduced by the transceiver unit.