Now, an indoor GPS system!

Finding your way around shopping plazas or airports may soon get easier -- thanks to scientists who have developed an indoor positioning system for cellphones similar to GPS.

The Global Positioning System doesn't work in buildings as the satellite signals it uses cannot get through walls. But, in this system, a cellphone can use nearby Wi-Fi transmitters instead of satellites -- it triangulates their signals to calculate its position, which it then displays on a map, the New Scientist reported.

The system is being currently tested in Finland.

In fact, it is not the first indoor system, but the others have mostly been for specialist uses, such as helping firefighters find colleagues in smoke-filled buildings. This system, developed by Nokia, will work with existing handsets and infrastructure, according to the scientists.

One thing it does need, however, is access to maps of the inside of buildings. This may not be feasible for private homes, but many public sites such as big sports centres and universities already make maps available.

And, if the ongoing test at Kamppi shopping centre in Finnish capital Helsinki is a success, then the system could be rolled out much more widely, said project leader Christian Prehofer.