Fibre-optic Cable Detection Systems
Fibre optic detection systems use fibre optic cables fixed to a structure as the sensing medium, converting vibrations in the protected structure into variations in a transmitted light signal.
The variations are very small but using a very accurate light source (such as obtained with a laser diode) and with a very sophisticated amplification and processing system it is possible to generate a voltage signal that has a direct relationship to the original vibration. Optical fibres are completely immune to electromagnetic interference generated by fast transients of current /voltage or atmospheric phenomena (lightning).
Various different configurations are available ...
SNAKE FIBRE OPTIC SYSTEM
The Snake system uses a processor unit that is connected to the sensitive cable via a variable length of non-sensitive fibre optic cable.
This makes the system extremely flexible in hardware configuration, with options to locate the processors centrally or distributed around the fence line, dependent on the site cabling infrastructure.
Each processor can monitor up to 2000m of sensitive cable, suitable for most types of fence structure.
The MILES Fibre optic detection system is based on a single mode fibre optic cable that has the highest level of detection while at the same time has a very low false alarm rate. It is completely immune to electromagnetic interference generated by fast transients of current /voltage or atmospheric phenomena (lightning).
The system is particularly suited to deployment in the protection of gas, water and oil pipelines and can use spare fibres contained within existing optical cables currently used for data transmission along the pipe, above or below ground. It can also be used to protect very long perimeter fences.
The fibre will detect attempts to drill into, damage or expose the pipe by digging and attempts to cut or climb the fence and then pass this information to a processing unit. The cable detects vibrations, pressure disturbances and movement. At least 20km of pipe/fence can be protected in this way.
No power supplies are required along the system and the attack location can be pinpointed to within a few tens of metres.