GPS Perimeter Systems are pleased to announce the launch today of our new fence mounted detection system, designated Snake.

Snake is a perimeter protection system that uses a fibre optic cable fixed to a structure as the detection medium, suitable for internal and external applications. It uses opto-phonic technology to detect all typical attempts to climb, cut or break through a fence and, for internal applications, it can indicate attempts to break through or penetrate a wall. Among the many advantages that fibre optic technology provide for fence mounted perimeter detection are accurate detection, the ability to cover long distances without the need for intermediate power supplies and in particular the complete immunity to high frequency interference from high voltage lines or atmospheric disturbances.

Fibre optics are also well suited to sites with corrosive or inflammable atmospheres or subject to extreme temperatures. Typical applications are sensitive systems for use on many different fence structures and also as a sensor to detect penetration on the surface or inside a wall structure (brick, blocks).


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. This in turn can give significant cost savings when installing a new system.


The sensing element is the optical fibre that carries light signals. These are subjected to variations directly correlated to the physical variations in the cable caused by intrusion attempts.

The digital signal processor (DSP) processes and analyses the variations in the signal generated by the differences between the transmitted and received light signals. It uses a sophisticated software algorithm, discriminating between natural phenomena, such as wind, rain, hail, etc, from attempted cut or climb intrusions.

Each Snake module is able to manage up to four optical fibre sensors and each of these can monitor a maximum fibre length of 2,000m for a total protection of 8,000m per module.