Japan: Japan’s Strategy Headquarters for Space Development decided that four navigation satellites will be sufficient to identify an object’s position on Earth with a high degree of accuracy. The original plan included constellation of seven satellites which was estimated to require about 230 billion yen fund. The four-satellite system is expected to cut this to about 150 billion yen.
Earlier in September 2010, Japan launched its first quasi-zenith satellite, Michibiki. The Headquarter realised that funding six more such satellites will be difficult while money is needed for restoration work in areas hit by the earthquake.
Japanese version of global navigation satellite system (GNSS) is scheduled to establish by 2014 and 2015 to cover the entire Asia-Pacific region. By supplementing and reinforcing GPS, the Japanese version will be 10 times more accurate than current positioning information.
Michibiki can be used only for eight hours a day–the time it is in orbit above Japan. With three more satellites in the sky, the four satellites can be used in turn to provide a highly accurate positioning system around-the-clock.
The Headquarters’ special investigation division plans to appropriate funds for developing quasi-zenith satellites in a 2012 budget. The headquarters, which is headed by Prime Minister Naoto Kan, will make a final decision on the number of satellites as early as this summer.
Source: The Daily Yomiuri