Nokia Research has developed indoor navigator to provide precise indoor location information on a handset, without needing GPS.
Nokia Indoor Navigation switches from Outdoor to Indoor mode as one approach the entry of a building.
Such feature is quite useful when trying to find a Terminal at airports or a specific exhibit inside a large exhibition hall. Nokia Indoor Navigation has an accuracy of 30 centimetre.
It requires a tracking device to be placed on the ceiling or a high visibility areas inside the building.