Satellites show blind people the way

A space-age audio guide!
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For blind people, finding their way around a city and arriving safely at their destination is far from easy. However, a new system based on data from navigation satellites may soon offer help for the visually impaired. Recent trials in Madrid have shown the value of the portable device for giving directions to the blind.

The system is actually a space-age 'audio guide', which has been developed by ESA, with the Spanish firm GMV. It is made up of a mobile phone, linked with a GPS location finder and a voice synthesizer. Seen from a distance, the blind person seems to be listening to music in a pair of headphones. In fact, he (or she) is hearing a voice telling him to turn right, left, or go straight ahead in order to reach the final destination.

What makes it possible to walk confidently through the city is EGNOS, an advanced satellite navigation system. It includes a network of about 40 ground stations scattered throughout Europe. These stations pick up signals from American GPS satellites, increase their accuracy and then retransmit them. As a result, EGNOS users can pinpoint their positions to less than two metres – the difference between being on a path or in the road. This compares with 15-20 metres for the basic GPS system.

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EGNOS is a joint project of ESA, the European Commission and Eurocontrol. It is the first step in the development of a European satellite navigation system. EGNOS is preparing the way for Galileo, which will use signals from 30 Earth-orbiting satellites.