초록 ▼

An apparatus and a method for measuring the distance to an arbitrary target includes a radiation source producing a beam of coherent radiation the frequency of which is continuously varied. The beam is divided into a ranging beam and a reference beam. The ranging beam is coupled to a ranging interfe

An apparatus and a method for measuring the distance to an arbitrary target includes a radiation source producing a beam of coherent radiation the frequency of which is continuously varied. The beam is divided into a ranging beam and a reference beam. The ranging beam is coupled to a ranging interferometer, which directs a portion of the ranging beam at the target. The ranging interferometer produces a first signal indicative of the phase difference between a portion of the ranging beam directed at and scattered by the target and another portion of the ranging beam which has traveled over a path of fixed length. The reference beam is coupled to a reference interferometer. A portion of the reference beam is directed by the reference interferometer along a reference path of a predetermined length, and the phase difference between the portion of the reference beam directed along the reference path and another portion of the reference beam which has travelled over a path of a fixed length is measured. The number of fringes resulting from the wave interference produced in the ranging interferometer and the number of fringes in the wave interference pattern produced by the reference interferometer are counted and used, together with the known length of the reference path, to determine the distance of the target from the ranging interferometer.

대표청구항 ▼

An apparatus for measuring the distance to an arbitrary target, said apparatus comprising: radiation source means for producing a beam of coherent radiation, said radiation source means including frequency modulating means for frequency sweep modulating the frequency of said radiation; first beam sp

An apparatus for measuring the distance to an arbitrary target, said apparatus comprising: radiation source means for producing a beam of coherent radiation, said radiation source means including frequency modulating means for frequency sweep modulating the frequency of said radiation; first beam splitting means, optically coupled to said radiation source means, for dividing said beam into a ranging beam and a reference beam; ranging interferometer means, optically coupled to said first beam splitting means, for directing a first portion of said ranging beam along a path toward said target and for producing a first wave interference pattern between a second portion of the ranging beam travelling over a first path and the first portion of the ranging beam scattered by said target, said ranging interferometer means including focusing means for focusing said ranging beam first portion onto said target; reference interferometer means, optically coupled to said first beam splitting means, for directing a first portion of said reference beam along a reference path of fixed predetermined known length and for producing a second wave interference pattern between a second portion of said reference beam travelling over a second path and the first portion of said reference beam travelling over said reference path; processing means, responsive to said first and second wave interference patterns, for determining the length of path between said ranging interferometer means and said target, said processing means including tracking filter means for filtering noise from said first wave interference pattern; and surface roughness processing means, responsive to the amplitude of said first wave interference pattern produced by said ranging interferometer means, for characterizing the roughness of the scattering surface to said target.