Japan is building its own GPS in the hope of reducing location errors for drivers, drone operators and other users.
A rocket launched on Thursday from southern Japan is carrying a satellite that will form part of a Japanese GPS.
An initial satellite was launched in 2010, and the Japan Aerospace Exploration Agency and Mitsubishi Heavy Industries plan to launch two more satellites by next spring to complete the "Michibiki" system. Michibiki is the Japanese word for guidance.
Japan currently relies on an American GPS. Having its own system is expected to reduce location errors in Japan to a few centimetres from as much as 10 metres by some estimates.
Three satellites will be visible at all times from the Asia-Pacific region, and the Japanese system could be integrated with the American one, enabling highly precise positioning, the Japanese government says.
The more accurate information could be used for both driving and drone deliveries. Japanese media report it also may enhance the country's defence capabilities.
Japan is considering adding three more satellites to the system in the future, as mountains and tall buildings will still affect the positioning under the four-satellite system.
