Japan on Saturday morning launched an intelligence-gathering satellite to spy on North Korea's military facilities. The optical satellite carries devices that can distinguish objects on the ground with a resolution of 60 cm and will supply the highest-definition photographs of all Japanese reconnaissance satellites, which have a resolution of up to 1 m.

Japan improved the definition when regulations were eased in August last year and is hoping to enhance it further to the level of American commercial satellites, which have a resolution of up to 40 cm.

Tokyo decided to develop the new satellites right after the North test-fired a long-range missile in 1998. Since then, it has launched five satellites. The latest will replace the first, launched in 2003, which has reached the end of its life cycle.

Two more optical and radar satelli tes are to be launched by 2011.

Transport Minister Seiji Maehara, who is in charge of Japan's space development, said the new optical satellite is the "core of the satellite system for Japan's security. It's important for Japan to gather intelligence on its own."

The satellite was carried by an H2A rocket developed by Japan with its own technology.