Abstract: A sensor for detecting a parking space includes a modulating module for supplying a sinusoid wave having a modulation frequency, an active antenna module transmits a FMCW signal based on the modulation frequency and for receiving a reflected FMCW signal, a intermediate-frequency filter for extracting a first demodulating signal having the modulation frequency from the reflected FMCW signal generating modulation signal, a second intermediate-frequency filter for extracting a second demodulating signal having a multiplying frequency of the modulation frequency, an integrator for performing integral operation for the second demodulating signal to generate an integral voltage, a triggering circuit for generating a triggering voltage when the integral voltage is greater than a reference voltage, and a controller for performing operations relating to an existence of a vehicle when receiving the triggering voltage.

Abstract: A sensor for detecting a parking space includes a modulating module for supplying a sinusoid wave having a modulation frequency, an active antenna module transmits a FMCW signal based on the modulation frequency and for receiving a reflected FMCW signal, a intermediate-frequency filter for extracting a first demodulating signal having the modulation frequency from the reflected FMCW signal generating modulation signal, a second intermediate-frequency filter for extracting a second demodulating signal having a multiplying frequency of the modulation frequency, an integrator for performing integral operation for the second demodulating signal to generate an integral voltage, a triggering circuit for generating a triggering voltage when the integral voltage is greater than a reference voltage, and a controller for performing operations relating to an existence of a vehicle when receiving the triggering voltage.