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FalTech and ViaLite provide GNSS/GPS signals inside a large exhibition hall

Lack of signal meant that some exhibitors were not able to demonstrate the full capabilities of their equipment.

The Background

ExCeL London is an international exhibition and convention centre in the Custom House area of Newham, East London.

Around 1,000 defence and security exhibitors were due to arrive to prepare for DSEI, a four-day event that hosts 30,000+ visitors from all over the world.

The building structure was blocking the ingress of GNSS signals, as the signals are too weak to penetrate into the interior.

Not totally surprising, since they have travelled 12,500 miles from the satellites to ground level on earth.

One exhibitor was planning to show their latest state-of-the art military helicopter and found that some of the on-board technology wouldn’t work due to lack of GPS signal.

Instead of moving the aircraft outside the building so it received a signal, FalTech was asked to provide a system to transport the outdoor GPS signal to the inside, to enable live demonstration of the aircraft capabilities.

The Challenge

Deployment of a standard GPS repeater system was initially considered. This involves a roof-mounted antenna, a length of coaxial cable and a repeater unit – also known as a re-radiator.

However, the distance from outdoor antenna to indoor repeater was about 100 meters.

The use of coaxial cable for connecting the antenna to the repeater was considered impractical for a number of reasons:

  • Low-loss cable is often several millimetres in diameter and is heavy and difficult to install over long distances.

  • Signal can be affected by electromagnetic interference (EMI), especially if it is positioned near power lines.

  • In-line amplifiers can be used to overcome signal losses caused by attenuation but can introduce unwanted noise and distortion.

The Solution

FalTech teamed up with RF-over-fibre manufacturer ViaLite, to create and install a system based on a 100 meter reel of single-mode fibre.

The fibre takes the place of coaxial cable.  It is immune to the effects of EMI and can extend the distance between antenna and repeater by up to 10Km if required.

The fibre was supplied on a small reel, and deployed more quickly and easily than the equivalent length of low-loss coaxial cable.

Once the fibre was installed, a pair of ViaLiteHD transceivers were installed.  One was placed near the outdoor antenna (TX unit) to convert the RF signal into a light stream.  

The other transceiver (RX unit) was placed at the far end of the fibre cable, adjacent to the planned GPS repeater location.

The RX device converts light energy back to an RF format, to provide an input to the repeater.

The Result

A GPS repeater was connected to ViaLite RX module, providing GNSS/GPS signal over an area of approximately 40 meters diameter.

The helicopter (and all other equipment fitted with GNSS receivers in the vicinity) were supplied with live signal without the need to go outside to obtain sky view.

The helicopter’s advanced systems were all operating as they would when positioned in open space outside the building.

Ultimately, the show was a great success for all concerned.

Phil Whitting, Managing Director at FalTechLtd, commented:

“A successful collaboration between FalTech Ltd, ViaLite Communications and the show organisers, meant that live GNSS signal was made available inside the building well in advance of the arrival of any vistors.”

ViaLite specialises in providing fibre links for many applications for the satcom, broadcast and time and synchronisation industries.

FalTech GPS offers ViaLite’s GPS-over-fibre solutions in a number of application environments, including GPS over fibre antenna links, coax-based RF splitters and  lossless optical splitters.

For more information you can email FalTech through the contact page or if you would prefer a good old-fashioned chat, we still have a telephone in the office. Please call 01326 336 444 in the UK or +44 1326 336 444 from outside the UK.

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