GPS navigation devices are all very well when out and about in open countryside, but perform woefully in some urban settings and stop working altogether in underground car parks and shopping centres.

That's precisely why Japanese firm Aichi Steel has invented a replacement for GPS that uses a combination of technologies to accurately plot locations anywhere on Earth.

Line of sight

The new device uses a geomagnetic sensor and an acceleration sensor to provide six axes of motion detection that can be processed to determine location.

Because it doesn't require line of sight to satellites like GPS does, the Aichi device will work well in the underground shopping malls that are common in cities like Tokyo and Seoul.

If trials go well, the company intends to commercialise it in 2009, with the possibility of combining it with GPS to provide a super-accurate car navigation system at some point.