Location, location, location

If you are on your way to catch up with a friend and can’t find the agreed meeting place, you can instantly download the location using a mobile phone with a GPS – Global Positioning System – receiver, and this is all possible due to the invention first developed by UK radio-astronomers.

In the late 1970’s and early 1980’s, a research group from Cambridge University wanted to measure the sizes of quasars (quasi-stellar radio sources) – the highly active cores of distant galaxies. This required a pair of radio antennas working together but separated by up to 1000 kilometres. One component was a large radio telescope at Cambridge, while the other was a small portable antenna that could be transported around the country on a trailer.

To work effectively, the researchers needed to know the position of the moving component to within a few metres. They realised that the transmissions from national FM broadcasts offered the solution – knowing the distance to each transmitter allowed them to pinpoint the component’s location.

It then didn’t take too long to see that the system could be miniaturised and applied to locating anything.

Nothing much happened at first because there was no immediate mass-market application. But then in the middle of the 1990’s, everyone started buying mobile phones – which contained all the necessary electronics. A company called Cambridge Positioning Systems was then set up to market the technology.

Today, the invention uses the signals from a mobile phone network to find a phone’s position to within 75 metres or so, and also to keep precise track of time. Many mobile phones have chips that detect signals from GPS satellite networks, but need help to work properly inside buildings. The satellite signals are so weak that the receiver has trouble finding them buried in the background noise. The Cambridge Positioning Systems device provides a precise time and approximate position to the satellite receiver, which can then dig into the noise at exactly the right spot to retrieve the satellite signals. The mobile-phone user remains unaware of what is happening behind the scenes, but enjoys a much faster and more accurate response.

In 2006, Cambridge Positioning Systems was bought by Cambridge Silicon Radio, which is now incorporating the technology into its Bluetooth chips.

…And all this came from UK radio astronomy which has made major contributions to a mobile phone location technology worth billions of dollars a year.

If you think you have what it takes to work in this fast-paced environment, you could be:

  • An astronomer – using a wide range of techniques to study the universe
  •  An electronics engineer – designing and developing electronic components and equipment in a range of industries
  • A telecoms technician – installing, testing and repairing communications and datacommunications systems
  • satellite systems technician – carrying out a wide range of tasks from installing new telecommunications systems and upgrading existing set-ups for a business, to repairing and realigning equipment after storm damage on a domestic property
  • design engineer – researching and developing ideas for new products and the systems used to make them, as well as working to improve the performance and efficiency of existing products


A version of this article was originally cited in ‘A new view of the universe’ published by the Royal Astronomical Society.