"The satellite will gather intelligence for our defense and diplomatic purposes," said Hisashi Michigami, an official at the Cabinet Office. "We hope to upgrade our ability to gather intelligence on our own. Intelligence gathering is vital to our national security."

While the older models were capable of distinguishing objects on the Earth's surface with a resolution of around 1 meter, the new model has improved the resolution to several tens of centimeters, the officials said.

The new satellite will undergo a performance trial for about three months before starting full-fledged operations, they said.

Japan has long relied on the United States for intelligence. But it launched its first pair of spy satellites in 2003, prompted by concerns over North Korea's missile program.

North Korea shocked Tokyo in 1998 when it test-fired a missile over Japan. Since then, Tokyo has launched spy satellites primarily to monitor developments in North Korea.

In April this year, a North Korean long-range rocket flew over Japan before landing in the Pacific.

Japan currently operates two optical satellites and a radar satellite, and the government is planning to add another radar satellite by March 2013 for a four-satellite system that will be able to film designated places on Earth at least once a day.

The satellite launched Saturday cost about ¥48.7 billion in research and development and around ¥9.4 billion for its manufacturing and launch, according to the officials.

Japan has long been one of the world's leading space-faring nations, having launched its first satellite in 1970, but in recent years has been overtaken by China.

While China put its first men into orbit in 2003, Japan has yet to send astronauts into space on its own.

Last year, the Diet voted to allow the nation's space programs to be used for defense for the first time as part of Tokyo's push to give its military a greater international role.