March 8, 2011

UK Report Warns Of Reliance On GPS

According to a report from the Royal Academy of Engineering (RAEng), the UK may have become dangerously over-reliant on satellite-navigation signals.

Use of satellite positioning and timing data is now widespread, and the academy fears that too many applications have little or no back-up if these signals were to go down.

It said receivers need to be capable of using a variety of data sources.

Dr Martyn Thomas, who chaired the group that wrote the report, told BBC News: "We're not saying that the sky is about to fall in; we're not saying there's a calamity around the corner. What we're saying is that there is a growing interdependence between systems that people think are backing each other up. And it might well be that if a number these systems fail simultaneously, it will cause commercial damage or just conceivably loss of life. This is wholly avoidable."

Global Navigation Satellite Systems (GNSS) such as Global Position System (GPS) are hugely popular and are finding more and more uses daily.

Satellite navigation systems are used by cellular and data networks, financial systems, shipping and air transport, agriculture, railways and the emergency services.

The European Commission estimated that about six to seven percent of Europe's DGP was now dependent in some way on GNSS data.

The RAEng report said satellite navigation signals are relatively weak and this leaves them open to inference or corruption.

Possible sources include deliberate jamming and natural hazards, like solar activity.  Both of these situations could introduce errors into the data or simply take it out altogether.

"The key thing for us is the concept of cascade failures," said report co-author Prof Jim Norton, the president-elect of BCS - the Chartered Institute for IT.

"This is what we characterize as accidental systems - systems that exist, but people don't recognize they exist because they don't understand the interdependencies. There will be a single common point of vulnerability and failure, but it's not obvious."

Thomas told BBC: "We concluded that the UK was already dangerously dependent on GPS as a single source of position, navigation and timing (PNT) data."

"[We concluded] that the back-up systems are often inadequate or un-tested; that the jammers are far too easily available and that the risks from them are increasing; that no-one has a full picture of the dependencies on GPS and similar systems; and that these risks could be managed and reduced if government and industry worked together."

The report made 10 recommendations, and three of which relate to raising awareness of the problems and get users to assess their own particular vulnerability.

Two cover hardware solutions, including the suggestion of a government-sponsored R&D program to seek better antenna and receiver technologies to enhance the resilience of systems. 

The report also lauds the land-based eLoran radio navigation system as a very worthy back-up technology.

Criminal gangs use jammers to hide their activity, such as blocking the GPS tracking systems in the high-performance cars they seek to steal.

These jammers can be bought off the Internet for a small price, and some are capable of swapping all receivers over a wide area.

"It's already illegal to put GNSS jamming equipment on the market in the UK," Jim Norton told BBC. "The problem is it's not necessarily illegal to hold it, to import or even to advertise it. It doesn't require legislation; it just requires [the telecoms regulator] Ofcom to place a banning order, and we would strongly recommend they do that."


Image Caption: Artist's impression of GIOVE-B in orbit. Credits: ESA


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