US 5,329,467 A · Distance measuring method and apparatus therefor

Abstract

A distance measuring method and an apparatus therefor, in which used are first and second pseudo random signals which are equal to each other in pattern but slight different from each other in frequency. A first time-series pattern obtained by multiplying the first pseudo random signal by the second pseudo random signal is generated, laser light intensity-modulated with the first pseudo random signal is radiated to a target, the light reflected from the target is received, and a intensity change of the received reflected-light is converted into an electric signal. A second time-series pattern is obtained by multiplying the electric signal as a reception signal with the second pseudo random signal. The distance to the target is measured by calculating the time difference between the first and second time-series patterns.

Claims7

Dependent claims

A distance measuring method comprising the steps of:

generating first and second pseudo random signals which are equal to each other in wave pattern but different from each other in frequency;
generating a first time-series pattern obtained by multiplying said first and second pseudo random signals by each other;
radiating laser light toward a target after intensity-modulating laser light with said first pseudo random signal;
converting a change in intensity of reflected light into an electric signal after reception of said reflected light as a reception signal from said target;
generating a second time-series pattern by multiplying said electric signal by said second pseudo random signal;
and
measuring a distance to said target by calculating a time difference between said first and second time-series patterns.

4 more elements

A distance measuring apparatus comprising:

means for generating a first pseudo random signal;
means for generating a second pseudo random signal which is equal in wave pattern to said first pseudo random signal but slightly different in frequency from said first pseudo random signal;
a first multiplier for multiplying said first pseudo random signal by said second pseudo random signal to thereby generate a first time-series pattern;
a laser light generation means for generating laser light intensity-modulated with said first pseudo-random signal;
a light transmission means for transmitting said laser light to a target;
a light detector means for receiving reflected light from said target and for converting said reflected light into an electric signal;
a second multiplier for multiplying said electric signal by said second pseudo random signal to generate a second time-series pattern;
a time difference measurement means for measuring a time difference between said first time-series pattern and said second time-series pattern;
and distance measuring means for measuring a distance to the target in accordance with said time difference.

6 more elements

Dependencies are inferred from the claim text.

Distance measuring method and apparatus therefor

Life of this patent

Distance measuring method and apparatus therefor

Life of this patent

Abstract

Claims7