Patent ID: 7330148

Claim:
A measuring apparatus for measuring at least a distance from an object, comprising: a transmitting means for alternately modulating amplitudes of a first continuous wave having a first frequency and a second continuous wave having a second frequency, wherein the transmitting means modulates amplitudes for transmitting a transmission signal as a carrier wave using an AM signal; an AM producing means for producing the AM signal used for the amplitude modulation; a receiving means for receiving a reflection signal of the transmission signal transmitted from the transmitting means and reflected by the object to be measured as a receipt signal; a first distance calculating means for: detecting a phase difference between a first Doppler signal for the first continuous wave and a second Doppler signal for the second continuous wave from the receipt signal received by the receiving means, and calculating a distance from the object to be measured according to a first method using the detected phase difference; a second distance calculating means for: demodulating the receipt signal received by the receiving means into the AM signal, detecting a phase difference between the AM signal after demodulation and the AM signal produced from the AM producing means, and calculating a distance from the object to be measured according to a second method using the detected phase difference; and a determining means for determining a final distance measurement result based on the distance calculated by the first distance calculating means and the distance calculated by the second distance calculating means.