Technology which was first developed for cruise missiles may give new independence to blind people. Yvonne Cook reports
Satellite signals which help ships to find their way at sea are being used in an experimental navigation system which could give a new independence to blind people.

Scientific engineer David Jones, based at the OU, his colleague Graham Moon and four sight-impaired volunteers, have just completed trials of the prototype system, which allows blind people independently to follow a route they have never taken before.

They are equipped with a computer which picks up signals from a Global Positioning System (GPS) satellite and identifies their location. Routes are pre-programmed into the computer, and the walker is guided by recorded instructions replayed through a headset. The headset allows walkers to hear noises around them as well as listen to the instructions.

The system can also be set to "direct explore" mode , allowing users to stand still (or sit) and explore their surroundings. The system tells them what is around them in any direction, and how far away it is.

To increase accuracy, the system also uses RDS - the technology used to tell car radios to which station they are tuned. Using these the walker's position can be identified accurately to within a few metres. To locate obstacles immediately in their path, walkers still rely on the traditional dog or cane.

Initiated and funded by David, the system has been developed over the past four years by Graham, a PhD student based at Nottingham University.

Gary Ankin, one of the trial volunteers, said: " This system means I can feel confident about finding my way along a route I have never been before. Without it, if I go to an unfamiliar place I have to rely on stopping people and asking them the way."

The system will function almost anywhere in the world. In future, it's possible to imagine computer route maps for visually-impaired people being provided for most towns and cities, parks, tourist attractions and complex sites such as the OU's campus (which frequently baffles sighted visitors). If so, blind people will be able to load the appropriate software into their pal - Personal Area Locator - and find their way to their destination.

But that's still in the future. "Now we know it works, what we need to do is to miniaturise the equipment," says David.

Currently the user has to carry, besides headphones, a laptop computer and a compass. All this, David reckons, could be reduced down to the size of a hand-held calculator, but it will take several years work, and more funds, to perfect. The funding situation is uncertain - the system has been developed on a shoestring. Graham's PhD is coming to its end. David is busy looking for new funding: "Without funds or anybody working on it full time, progress will be slow or, worse, it will grind to a halt."