GPS over Fibre

A GPS-over-fibre optical link extends the antenna feeder cable well beyond the maximum distance supported by coaxial cable-based systems.

Extend the distance between the GPS antenna and the GPS repeater/receiver to reach places where signals are otherwise unavailable, where installation of coaxial cable is impractical.

A GPS receiving antenna is placed outside the building, preferably at roof level where it has a clear view of the sky to ensure it can “see” as many satellites as possible.

A coaxial cable runs from the antenna to a location just inside the building, and terminates on an optical transmitter (TX) module. It can be placed inside a waterproof enclosure if it needs to be placed outdoors.

The transmitter module converts the RF signals into light by modulating a laser light source; the modulated light is then transported through an optical fibre to the optical receiver (RX) module.

The RX module converts the light signal back into its original RF form, then amplifies and impedance matches it to the attached GPS receiver/repeater.

Benefits of fibre optic cable

Increased range when compared to coaxial cable systems – up to 1,500 metres on multi-mode fibre, and 10Km over single-mode fibre
Optical fibre is a non-conducting dielectric glass media, is immune to strong electromagnetic fields and can be installed near high-voltage cables
Signals suffer minimal degradation or delay
Optical fibres can be routed safely through explosive or flammable atmospheres, for example, in petrochemical industries or munitions sites, without risk of ignition
With the appropriate conversion devices, optical fibres can carry a huge range of RF signals with much less energy than copper cable and with significantly higher bandwidth
Compared to thick, low-loss coaxial cable it is small, lightweight, easier to install and is durable
The cost of a 200m single-mode fibre link is lower than the equivalent length of coaxial cable and amplifiers