Deep in the bowels of Edinburgh University, scientists are using 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, the Global Positioning System. They believe they can use the light from LED bulbs 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. As long as we are in the line of sight of the light source.
For Povey, this is not just some laboratory dream. "We don't have to wait for tomorrow's smartphone," he says. "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. But there are at least 15 other technologies engaged in the race to replace the elements of GPS. 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", says 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.
GPS has only been embedded in our everyday lives over the past decade, but its origins date back to the ground-based radio navigation systems that helped the Allied bombers 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 Ronald Reagan decided to make GPS "free to everyone" after Korean Air Flight 007 was shot down by the Russians in 1983 when it 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 and not disappear the moment you enter a building or even the urban jungle", Malik says. 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". And there is 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".
Of course, GPS can be updated at great expense – GPS III is coming soon if it survives Barack Obama's budget cuts – or it can be "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 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.
But Professor Malik sees Wi-Fi as the No 1 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 chief executive 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 says. "We have had only a few requests, mostly at the top end, for apps to be able to switch to Wi-Fi... 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 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 "there is always opportunity for people to come in and disrupt the market with stuff I hadn't even thought of".
Back in Edinburgh, Povey's location research may soon be spun-off from the university because there should be "some apps on modified machines available by the end of the year". He says: "There is still a role to play 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.