According to reports, the International Marine Aids to Navigation Exhibition opened yesterday in Shanghai. Automatic Identification System (AIS) response, one of the most advanced digital aids to navigation, was launched to help build an expressway for ships to sail faster and safer to port. Aids to navigation, termed the ears and eyes of ships, help sailors to know their position at sea. Shanghai port built its first aid to navigation, the Sheshan Mountain lighthouse, in 1871. According to the data, by the end of 2005 Shanghai had built 632 aids to navigation, up by 122% since 2002. From lighthouses and beacons to radar responders and GPS (Global Positioning System), Shanghai¡¯s navigational aids have now entered the digital era.