The North Korean spy ship salvaged earlier this month from the East China Sea was carrying a global positioning system, the Japan Coast Guard said Saturday, adding that the device may contain information on the ship's previous journeys.
The coast guard announced Friday that a small boat stored aboard the main ship was equipped with a similar device.
Coast guard officials said the GPS was discovered within a double door at the stern of the spy ship. The system, widely used in car navigation, is used to determine a position on the Earth's surface by comparing radio signals from several satellites.
The coast guard plans to examine the data stored in the GPS to determine the ship's past routes when the ship is brought to shore in October, the officials said.
One type of GPS can store more than 10,000 hours of navigation records, according to the officials.
A North Korean submersible sunk by the South Korean navy in 1998 carried a Japanese-made GPS, the coast guard officials said.
The GPS on the spy ship is likely to have been made in Japan and was either imported to North Korea via a third country or was previously used aboard a Japanese fishing boat that North Korea bought, they said.
The spy ship sank after exchanging gunfire with coast guard patrol boats on Dec. 22. It was raised from the seabed some 390 km off the Amami Islands in Kagoshima Prefecture, on Sept. 11.
During the Sept. 17 summit meeting with Prime Minister Junichiro Koizumi in Pyongyang, North Korean leader Kim Jong Il admitted the country's military had operated spy ships around the Japanese archipelago.