ODiSI-B Sensor Strain Gage Factor Uncertainty
Averaging results over multiple sensor fiber spools, Luna observes a Strain Gage Factor of -6.6165 µε/GHz and estimates a measurement uncertainty of ± 0.0179 µε /GHz (0.27%).
Luna’s Optical Distributed Sensor Interrogator (ODiSI) instruments use swept-wavelength interferometry to produce a high spatial resolution map of the sensor Rayleigh scatter pattern. By comparing a sensor measurement Rayleigh scatter pattern to a reference pattern, the scatter pattern optical frequency shift as a function of sensor length can be determined and scaled to a strain or temperature change. This Engineering Note details the method for determining the strain calibration coefficient (or strain gage factor), estimates the degree of uncertainty associated with the gage factor value, and presents data on the variability of strain gage factor measurements within a single fiber spool and over multiple fiber spools.