Device and method for monitoring a target component or a set of target components through electrical time-domain or frequency-domain reflectometry

A method for manufacturing a device for monitoring a target component or a set of target components through electrical time-domain or frequency-domain reflectometry, said device comprising:

• an electromagnetic waveguide comprising an input end and an output end;
• an interrogator electrically connected to the input end of the electromagnetic waveguide and configured to inject an incident signal via said input end and to receive a signal reflected by the electromagnetic waveguide in response to said injection, the reflected signal comprising a back echo reflected by the output end of the electromagnetic waveguide;
• the electromagnetic waveguide comprising, between the input and output ends of said electromagnetic waveguide, a measurement part comprising more than 10 discontinuities, called “base discontinuities”, per meter of electromagnetic waveguide, which are:
• randomly distributed at least along the measurement part of the electromagnetic waveguide;
• and are
• capable of generating echoes, called “base secondary echoes”, with an amplitude of more than 1% and less than 30% of the amplitude of the back echo reflected by the output end of the electromagnetic waveguide, wherein said electromagnetic waveguide is manufactured:
• by disposing first and second electrical conductors parallel to each other;
• then
• by locally modifying the impedance of at least one of said electrical conductors by creating more than 10 base discontinuities per meter of electromagnetic waveguide, along the length of the electromagnetic waveguide, with the base discontinuities having random shapes and being randomly distributed,
• an input end of the electromagnetic waveguide being connected to said interrogator.

A method for determining a property of an environment in an “updated” situation, said method comprising the following steps of:

• a) introducing an electromagnetic waveguide into said environment comprising, between input and output ends of said electromagnetic waveguide, a measurement part comprising a more than 10 discontinuities, called “base discontinuities”, per meter of electromagnetic waveguide, which are:
• randomly distributed at least along the measurement part of the electromagnetic waveguide;
• and are
• capable of generating echoes, called “base secondary echoes”, with an amplitude of more than 1% and less than 30% of the amplitude of a back echo reflected by the output end of the electromagnetic waveguide;
• then
• in a reference situation of said environment:
• b1) injecting an incident signal via said input end at a “reference” instant;
• c1) receiving a signal, or “reference reflected signal”, reflected by the electromagnetic waveguide in response to said injection;
• and
• in the updated situation of said environment:
• b2) injecting the incident signal identical to that injected in step b1) via said input end at an “updated” instant;
• c2) receiving a signal, or “updated reflected signal”, reflected by the electromagnetic waveguide in response to said injection;
• d) analyzing the reference and updated reflected signals so as to determine said property of said environment in the updated situation;
• e) optionally, transmitting a message relating to said property or to an evolution of said property relative to a situation prior to the updated instant;
• with step d) comprising the following steps:
• 1) determining an intercorrelation function between:
• a “reference” portion of the reference reflected signal;
• and
• an “updated” portion of the updated reflected signal;
• with the reference and updated portions being portions of the reference and updated reflected signals, respectively, delimited by the same measurement window, centered on an instant, called “window position”, defined relative to the start of the reference and updated reflected signals;
• with the maximum of the intercorrelation function, or “maximum correlation”, being obtained for a phase shift called “main phase shift”;
• 2) determining, based on the main phase shift and/or the maximum correlation, a correlation index;
• and
• 3) determining, based on said correlation index, a value of said property in the updated situation and/or an evolution of said value of said property;
• said environment being, in the updated situation and/or in the reference situation, at a temperature of more than 125° C. and the electromagnetic waveguide being configured so as not to melt, even partially, at the temperature of the environment.