Patent ID: 8941836
Filing Date: 2015-01-27
Classification: G01J,G01N

Abstract:
1. A metrology system applied to an interferometer for remotely analysing a gaseous compound by Fourier transform spectroscopy, said interferometer being a two-arm interferometer, comprising at least one movable retroreflector, the metrology system comprising: a laser device configured to inject at least three metrology laser beams input into the interferometer; a capture subsystem for receiving at least three metrology laser beams output by the interferometer, said capture subsystem delivering at least three laser signals each representing a measurement of an interference of one of the metrology laser beams after passing through the interferometer; at least one metrology unit which, from one or more of the at least three laser signals, generates synthetic metrology signals for various points in a field of view of the interferometer, the synthetic metrology signals thus generated taking into account a path of the at least one movable retroreflector in space and said metrology unit including a metrology calculation component which estimates, for each received laser beam, absolute optical path differences, said at least one metrology unit including three metrology calculation units each calculating a raw metrology signal from a corresponding laser signal; and a unit configured to generate one synthetic metrology reading per measurement point, and to generate, from at least three raw metrology signals, one synthetic metrology signal per measurement point in the field of view of the interferometer, wherein the unit is configured to perform at least the following processing steps: an estimation of a vector apex joining the positions of the vertices of the at least one movable retroreflector, an elimination of the linear component of the vector apex; and a generation of an optical path difference represented by a synthetic metrology signal, at different points in the field of view, from the vector apex and from the angular coordinates of the various points in the field of view.