NOVA strain sensing technology

NOVA-Strain Sensing is a patented application based on novel range-resolved interferometric signal processing technique.
Strain applied to a NS (NOVA-Segment), that is the strain sensing element, induces a phase change to the carrier signal of the reflectors. In detecting the phase change from the reference fibre cleaved end, it is possible to quantify the elongation and so the integral result of strain applied along the segments.

Working principle

An elongation along fibre axis cause an increase (or decrease) in the NS length.
The system is capable of detecting the difference in length of each of the segment from the cleaved end, that act as a reference point.
Subtracting the segment delta L from the reference it is possible to have the single segments dL and so the strain generated.

RESOLUTION
the smallest change in the underlying physical quantity that produces a response in the measurement

dL = 1 e-5μm to 1 e-3μm

the path length of the interferometer and sensors installation.

ACCURACY & PRECISION
Accuracy is the degree of closeness of measurements of a quantity to that quantity's true value.
Precision is the degree to which repeated measurements under unchanged conditions show the same results. The accuracy and precision of a measurement process is usually established by repeatedly measuring some traceable reference standard.
This applies when measurements are repeated and averaged, the precision of the average (sensitivity) is equal to the known standard deviation of the process divided by the square root of the number of measurements averaged.

sensitivity = 0.22 nε/sqrt(Hz)