Fibre Optic Distributed Sensing

A method of processing data from a distributed fibre optic sensor comprising the steps of:

• taking data corresponding to detected electromagnetic radiation which has been back-scattered from an optical fibre;
• processing said data to provide a measurement signal for each of a plurality of longitudinal sensing portions of the optical fibre;
• and
• analysing the measurement signals from the longitudinal sensing portions to detect events of interest, wherein the method comprises
• analysing the measurement signals of a first subset of longitudinal sensing portions to provide a first zone having a first sensing function and analysing the measurement signals of at least a second subset of longitudinal sensing portions to provide at least a second zone having a second, different, sensing function.

A distributed fibre optic sensor apparatus comprising:

• an optical fibre;
• a source of electromagnetic radiation configured to launch electromagnetic radiation into said fibre;
• a detector for detecting electromagnetic radiation back-scattered from said fibre;
• and
• a processor configured to:
• analyse the back-scattered radiation to determine a measurement signal for a plurality of discrete longitudinal sensing portions of the optic fibre;
• wherein the distributed fibre optic sensor comprises a first zone having a first sensing function, the first zone corresponding to a first subset of said longitudinal sensing portions and at least a second zone having a second, different, sensing function, the second zone corresponding to a second, different, subset of said longitudinal sensing portions.