Satellites in the driving seat?

The GPS already tells us how to get from A to B. In the future, it could also play an increasing role in road safety.

 

Current vehicle navigation devices use GPS, based on a constellation of thirty or so NAVSTAR (Navigation Satellite Timing And Ranging) satellites orbiting at an altitude of 20,000km. Europe is preparing its own system, called Galileo (left: artist's impression of a Galileo satellite). Image credit: ESA - J. Huart - P. Sebirot

It didn't take long for satellite positioning to find its way into our cars - thanks to navigational devices using the GPS signal. Today, it's quite the norm to hear a computerised voice say "turn left", guiding the driver to a new destination.

From road map to safety
The satellite is taking over from the road map, adding real-time monitoring that triggers spoken instructions. GPS receivers are what the name implies: they simply receive signals emitted by thirty or so satellites circling above our heads at an altitude of 20,000km. Position calculations are based on the time lapse between the instant the signal is emitted by several satellites (at least 3) and its arrival at the GPS receiver. There is no orbital "Big Brother" to be feared, as the satellites do not get any information back from the GPS receiver – although this could prove very useful in an emergency: road accident victims are sometimes unable to describe precisely where they are when they call for help, not to mention cases when they are so seriously injured they cannot even call for help!
The European Union and the European Space Agency are preparing their own civil satellite navigation infrastructure: Galileo (the current GPS is American, controlled by the army). The goal is to go further, integrating into the system the ability to receive distress signals. If that were the case, cars could be fitted with a device for geolocation via satellite that could emit the vehicle's position at the driver's request, should the latter find him- or herself in need of emergency services. Galileo's very precise coordinates (accurate to within 50cm!) will enhance the relevant services' efficiency and speed. A device that is automatically triggered in the event of a severe impact - as an airbag is – is also a possibility.  The typical scenario (but obviously not the only one) is a driver who becomes unconscious when his or her vehicle crashes off a very quiet road. The system could save their life!

Illustration showing the European constellation of Galileo satellites. Image crédit : ESA - J. Huart

Satellite says: "Slow down"
Vehicle positioning determined by a GPS receiver (or Galileo in the future) has already been harnessed into concrete applications. Many transport companies follow the movements of their fleets of lorries in this way. Feedback on location is not via satellite, however, but over mobile phone networks. Such real-time information is conducive to the optimal management of delivery itineraries and major fuel savings (incidentally also reducing gas emissions). Can we go further, and imagine satellites actually taking the wheel, to optimise journeys and avoid accidents? The road to the car driven by computer turns out to be particularly complex as there is so much data to be incorporated. A satellite will therefore not be enough. On the other hand, with finesse in the order of one metre, Galileo could point out to the driver the speed limit on the portion of road s/he's on. Satellites may not be taking the wheel, but they could very soon ask you to take your foot off the accelerator...

Published on 27 August 2009