Distance measuring device, distance measuring method and distance measuring program

A distance measuring method of measuring a distance to an object of measurement, comprising the steps of:

• outputting a signal having a variable frequency;
• generating and emitting to said object of measurement an electromagnetic wave of the same frequency as said signal;
• detecting a reflected wave of said electromagnetic wave;
• and
• calculating a distance to said object of measurement by an operation of a relation between said detected reflected wave and the frequency of said signal;
• wherein
• said step of detecting a reflected wave includes the step of
• extracting a phase change component of said reflected wave by synchronous detection of said detected reflected wave with said signal;
• and
• said step of calculating the distance to said object of measurement includes the steps of
• changing variable frequency of said extracted phase change component by a frequency corresponding to a prescribed distance,
• taking, as an analysis signal, one of upper and lower side bands obtained by said frequency change, and
• performing Fourier transform on said analysis signal to calculate a profile, and finding distance to said object of measurement based on a local maximum of said profile and said prescribed distance.

A signal processing device for a distance measuring device measuring a distance to an object of measurement,

• said distance measuring device including a sending source outputting a transmission signal having a variable frequency, a transmission unit generating and emitting to said object of measurement an electromagnetic wave of the same frequency as said transmission signal, and a detecting unit detecting a reflected wave of said electromagnetic wave;
• and
• said detecting unit performing synchronous detection of said detected reflected wave with said transmission signal, to extract a phase change component of said reflected wave,
• said signal processing device configured for
• changing variable frequency of said extracted phase change component by a frequency corresponding to a prescribed distance,
• taking, as an analysis signal, one of upper and lower side bands obtained by changing said frequency, and
• performing Fourier transform on said analysis signal to calculate a profile, and finding distance to said object of measurement based on a local maximum of said profile and said prescribed distance.