Patent ID: 8174434
Filing Date: 2012-05-08
Classification: G01S

Abstract:
1. A method for determining a distance to a target object, the method comprising the steps of: a) transmitting radio frequency electromagnetic waves as an outgoing signal using a transmitter; b) receiving, using a receiver, at least a part of the outgoing signal reflected on the target object to generate an incoming signal; c) converting the incoming signal and a reference signal into a digital signal; d) reducing, using a frequency divider and following step c) while maintaining a phase difference between the reference signal and the incoming signal, a frequency of the reference signal and a frequency of the incoming signal by a same pre-determinable divider factor to obtain a frequency-reduced reference signal and a frequency-reduced incoming signal, wherein the reference signal has a known phase difference with respect to the outgoing signal and a same frequency as the outgoing signal; and e) evaluating, following step d), a phase difference between the frequency-reduced reference signal and the frequency-reduced incoming signal to determine the distance to the target object, wherein an output voltage, which is proportional to the phase difference between the frequency-reduced reference signal and the frequency-reduced incoming signal is obtained from the frequency-reduced reference signal and the frequency-reduced incoming signal using a phase comparator.