Optical sensing system for determining the position and/or shape of an associated object

An method of determining the position and/or shape of an associated object, the method comprising;

• providing one or more optical fibers for spatial fixation on, in, or to said associated object, each optical fiber having one or more optical fiber cores,
• providing a plurality of optical fiber cores having one or more fiber Bragg gratings extending along the full length of said optical fiber cores where the position and/or shape is be to determined of said object,
• providing a reflectometer optically connected to said one or more optical fibers, the reflectometer being optical arranged for measuring the strain at a number of sampling points along the plurality of optical fiber cores, and
• providing a processor operably connected to the reflectometer for determining the position and/or shape of the object based on said measured strains from the plurality of optical fiber cores,
• wherein the reflectometer, when working in the frequency domain, is arranged for performing a wavelength scan from a first wavelength to a second wavelength around a central wavelength (λ0) for the determining said position and/or shape, the one or more fiber Bragg gratings extending along the full length of said optical fiber cores, each of the one or more optical fiber core having a spatially modulated reflection along the said full length of the optical fiber core so that the corresponding reflection spectrum is detectable in said wavelength scan.

An optical unit to be applied in an associated optical sensing system for determining the position and/or shape of an associated object, the optical unit comprising;

• one or more optical fibers for spatial fixation on, in, or to said associated object, each optical fiber having one or more optical fiber cores, and
• a plurality of optical fiber cores having one or more fiber Bragg gratings extending along the full length of said optical fiber cores where the position and/or shape is be to determined of said object,
• where the optical unit is connectable to an associated reflectometer, the reflectometer being optical arranged for measuring the strain at a number of sampling points along the plurality of optical fiber cores, an associated processor further being connectable to the reflectometer for determining the position and/or shape of the object based on said measured strains from the plurality of optical fiber cores,
• wherein the reflectometer, when working in the frequency domain, is arranged for performing a wavelength scan from a first wavelength to a second wavelength around a central wavelength (λ0) for the determining said position and/or shape, the one or more fiber Bragg gratings extending along the full length of said optical fiber cores, each of the one or more optical fiber core having a spatially modulated reflection along the said full length of the optical fiber core so that the corresponding reflection spectrum is detectable in said wavelength scan.