'Whatever the technology, real-time locating systems are all about triangulation'
'Whatever the technology, real-time locating systems are all about triangulation'

Does GPS need replacing?

Mark Piesing looks at the contenders hoping to plot a fresh navigational path.

Mark Piesing
Thursday 02 February 2012 01:00

Deep in the bowels of Edinburgh University, scientists are using a much talked-about – and talked-up – cutting-edge communication technology to answer the eternal question: "Daddy, are we nearly there?"

Professor Gordon Povey and Wired magazine pin-up Professor Harald Haas believe that visible light communication – or li-fi – can challenge the dominance of GPS, or the Global Positioning System. They believe they can use the light emitted from LED lightbulbs placed in buildings to transmit data, not only to download the latest film to a laptop, but also to tell us where we are with pinpoint accuracy. Just so long as we are in the line of sight of the light source.

For Povey, this is not merely some laboratory dream. "We don't have to wait for tomorrow's smartphone. We can already do things on today's phones that will use the low-speed visible light emitted from these LEDs to work out your exact position. So you won't have to stumble around a strange hotel for a GPS fix any more. You'll be able to see where you need to go."

The How Do They Do It? of this new technology is – not surprisingly – still stamped Top Secret. However, there are at least 15 other technologies engaged in the race to replace the elements of GPS on which we have come to depend. This race is perhaps inevitable, as some of the system's physical infrastructure and software is now more than 30 years old and ripe for "disruption".

Whatever the technology, these real-time locating systems (RTLS) are all about "triangulation", explains Professor Ajay Malik, former head of engineering for Motorola and author of RTLS for Dummies. In the case of GPS, this means your position is worked out to within a few metres' accuracy (depending on your handset), relative to four or more of the GPS navigation satellites visible to your device at a given time, out of about 30 satellites in total. Assisted GPS or A-GPS on mobile phones uses the computer power of the phone networks to help make these same calculations – if more slowly – when the radio signal from the satellites is poor.

Even though GPS has only really been embedded in our everyday lives over the past decade, its origins date back more than 70 years to the ground-based radio navigation systems that helped the Allied bombers to devastate Germany in the Second World War. In 1973 a group of US Army officers came up with the idea of a global satellite navigation system – although it would then take 21 years before the network's final satellite would be launched into orbit.

Before then, in a move that explains its great success, President Reagan decided to make GPS "free to everyone" after Korean Air flight 007 was shot down by the Russians in 1983, due to its having accidentally strayed into prohibited airspace. This apparent navigational error cost 269 lives.

Yet the "it sells itself" proposition that this great giveaway helped to create, perhaps, disguised the weaknesses of the system. While its accuracy is "good enough" for cars and "OK" for walkers, "any location technology has to be internally and externally ubiquitous," says Malik, "and not disappear the moment you enter a building or even the urban jungle." As well as its relatively weak signal and the time it can take to get a fix, "if you are running an application that uses GPS the battery runs out so quickly".

Not forgetting the vulnerability of GPS to hacking, spoofing and blocking by anyone from bored teenagers in Essex to the Chinese military, which is "only going to get worse" as "it is easy to do because GPS is freely available and popular".

Of course, GPS can be updated at great expense – GPS III is coming soon if it survives Obama's budget cuts – or it can be even "leapfrogged" by more advanced sat-nav technology.

Europe's Galileo system offers metre precision and the "major advance" of a Search and Rescue function, which, after a beacon has been activated, tells those waiting when help is on its way.

Or it can simply be replaced, for example by China's Compass and Russia's Glonass, regional navigational systems that are expected to go global by 2020. Similarly, Boeing rebooted its network of 71 Iridium low-orbit satellites by uploading new firmware, to create a cheap-to-set-up alternative to GPS called the Timing and Location Network, which broadcasts a powerful signal from a low altitude that can penetrate buildings.

Alternatively, there are more than 15 other technologies here or on the way. They range from tracking based on mobile phone masts to Bluetooth. They could provide, in the first instance, more accurate and reliable positioning within buildings or built-up areas, as they don't need to see the sky. Or indeed, a "hybrid" system that uses the best available signals.

Others include more radical technologies such as visible light communication and ultrasound (which may be bad news for dogs). Ultrasound uses small tags carried by an individual to transmit a unique acoustic signal inaudible to the human ear every five seconds, which is picked up by a receiver and the data transmitted to a server.

However, Professor Malik sees Wi-Fi as the "number one" alternative to GPS. Software developed by Boston-based Skyhook Wireless can work out your location relative to the more than 250 million Wi-Fi transmitters in the United States, Canada and Western Europe that they have been able to map out, covering 70 per cent of the population.

Yorkshireman Steve Page is sceptical of some of the claims regarding these new technologies. Page is CEO of Mobilecommerce, leading designers of "location" apps for brands such as the AA. "There is a big difference between what gets talked about in the press and by scientists, and what people actually are doing," he argues. "We have had only a few requests, mostly at the top end, for apps to be able to switch to Wi-Fi.

"After all," he says, "consumers just want three things from location technologies: find out what's around them, work out how to get there and how to find someone or something."

And GPS delivers all that.

Although "with a transmitter in almost every other house in my village, Page admits that a technology like Wi-Fi "could offer a reasonably accurate system", even if "there will always be the space in between" that will need something like GPS.

And of course, "there is always opportunity for people to come in and disrupt the market with stuff I hadn't even thought of."

Back in Edinburgh, Gordon Povey's location research may soon be spun-off from the university as there should be "some apps on modified machines available by the end of the year".

"There is still a role to play," he says, "for spin-offs and start-ups as minimal viable product developers who pioneer the applications, before companies like Samsung decide there is a market and buy them out.

"We are better at figuring out what needs to be done; big business is better at filing patents and getting intellectual property."

So if you have a few million to spare, it is not too late to invest.

Global positioning: A timeline

1940s Development of long range navigational systems like LORAN based on earlier British technology

1973 Global Positioning System first imagined

1978 First GPS satellite is launched

1983 Ronald Reagan decides to make GPS free-of-charge

1994 Initial network of 24 GPS satellites completed

1996 Clinton signs order formally recognising the dual use of GPS by civilians and the military

2000 Civilians get access to the higher-quality military signal

2001 First mobile phone with embedded GPS

2002 First TomTom product is released

2010 LORAN is turned off

2012 GPS on mobile phones to become standard

2014 First GPS III satellite is scheduled to launch

China's Compass

Both China and Russia (with Glonass) have their own navigation systems. Expected to go global by 2020.


An update to the US GPS system will be a major advance on the previous GPS... if budgets allow

Boeing timing and location

Boeing's own systemsends a powerful signal from a low altitude


The European Union and Space Agency's precise system features a "search and rescue" beacon


A Wi-Fi triangulation system could work out where you're located between different Wi-Fi routers

LED (li-fi)

Scientists believe that they can use the light emitted from LEDs to define locations

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