TOKYO — After a decade-long delay, Japan has committed to building its own regional satellite navigation system by 2020 that will be compatible with the U.S. GPS satellite navigation constellation.
Configuration and launch schedule details are set to be released by April.
With China looking to complete its 35-satellite Compass system by 2018, the effort is strategically important for Japan to secure independent access to positioning services if contingencies arose where GPS became inaccessible.
“Space development offers unlimited potential for the security of Japan, and I have promised to develop a functional system in the second half of this decade,” Prime Minister Yoshihiko Noda told the Japanese Diet in a nationally televised question-and-answer session Oct. 5.
Japan’s Quasi-Zenith Satellite System (QZSS) will have an encrypted signal and eventually provide Tokyo with independent GPS-like positioning functions later, if a full seven-satellite system is funded. Noda formally committed to the program Sept. 30, and his Cabinet Office has requested an initial 4.1 billion yen ($53.4 million) for the next fiscal year beginning in April to start building satellites.
Costs for the system range from 170 billion yen for a four-satellite system to 260 billion yen for the seven-satellite system. These figures include launch and ground systems costs, according to Hiroshi Yamakawa, secretary general of the Strategic Headquarters for Space Policy (SHSP), which is part of the Cabinet Secretariat in the Cabinet Office and is Japan’s top advisory body on space development.
QZSS, as conceived about 10 years ago, was to have been developed by a public-private partnership, but this plan fell through in the middle of the last decade when a large commercial consortium pulled out.
While a 2007 law allowed public money to fund an experimental satellite called Michibiki — which was successfully launched in September 2010 and has been functioning well — no bureaucratic framework existed among several ministries involved in developing and controlling the satellite navigation system.
Noda’s go-ahead means the Cabinet Office will be responsible for both the budget and development of QZSS, clearing the logjam, Yamakawa said.
“The launch of Michibiki was the first major step, and now the Sept. 30 decision was a major step toward a fully functional [global navigation satellite system],” he said. “In addition, the Cabinet is able to exercise leadership that crosses over inter-ministerial responsibilities. Our function is now to coordinate these.”
QZSS works by placing satellites in orbits that allow them to dwell for more than eight hours a day with an elevation above 70 degrees, meaning they appear almost overhead most of the time.
The SHSP is looking at an initial system of four satellites that will provide 24-hour coverage. A seven-satellite system — with one or more satellites in geostationary orbit — will be needed for Japan to have its own independent GPS-like services.
Yamakawa stressed that QZSS was conceived and designed to be fully compatible and interoperable with GPS.
The SHSP has been engaged in several years of debate about reforming bureaucratic control of Japan’s space development following the passage of the Basic Law for Space Activities in 2008, requiring the government to institute Cabinet control of Japan’s space programs.
This has been opposed by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), which controls about 60 percent of Japan’s $3.5 billion annual space budget.
Takafumi Matsui, deputy chairman of a special committee set up in the SHSP that recommended the change, said giving the Cabinet Office responsibility to control QZSS was important on two counts.
First, aside from promoting cooperation with the U.S., Japan needs a backup in case GPS becomes unavailable or inaccessible as China fields its own satellite navigation system.
Second, Matsui said the Sept. 30 decision was a significant step toward asserting more control over space development at a later date.
In a June 30 report, Matsui’s committee had recommended that Japan take steps to set up a space agency in the Cabinet Office that would also take over about 30 percent of MEXT’s budget. Although the Sept. 30 decision means the Cabinet Office only takes control of QZSS, it still represents a significant first step toward the Cabinet Office gradually exerting more control, Matsui said.
“It’s good news. It’s almost as we’d planned,” he said.
Goro Onoyama, deputy director of MEXT’s Space and Aeronautics Policy Division, said it supports the Cabinet’s decision in as it relates to QZSS. “We recognize that user ministries, the Cabinet Office at the core, will collaborate on the QZSS of practical use,” he said. “We will help them effectively use what has been proved through the operation of the first QZSS.”
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