Patent ID: 7145502

Claim:
A distance measuring method for measuring a distance from a reference position to an object to be measured, comprising the steps of: a standing wave generating step for generating traveling waves that travel from the reference position to the object to be measured in a propagation medium existing surrounding the reference position and the object to be measured while varying the frequency, and causing the generated traveling waves to interfere with the waves reflected by the object to be measured to thereby generate standing waves; a standing wave detecting step for detecting the standing waves generated in the standing wave generating step; a radar image calculating step for calculating a plurality of radar image functions from the standing waves detected in the standing wave detecting step based on a plurality of different center frequencies in which radar image functions a variable is a distance from the reference position to a point on an imaginary linear axis passing through the object to be measured; and a distance judging step for judging, as the distance from the reference position to the object to be measured, a distance in which predetermined conditions are satisfied by phase differences among a plurality of radar image functions calculated in the radar image calculating step and by an amplitude of any of the radar image functions.