TOKYO — A key consultative committee has strongly endorsed the development of Japan’s Quasi-Zenith GPS augmentation system and recommended that a messaging capability and perhaps other functions related to disaster management be added. The endorsement boosts the prospects of the Quasi-Zenith Satellite System (QZSS) to make the transition from a single-satellite technology demonstration to a key part of Japan’s space infrastructure, according to committee members.
An April 22 report by the QZSS Working Group at the Strategic Headquarters for Space Development (SHSP) —Japanese Prime Minister Naoto Kan’s top advisory body on space development — recommended Japan launch at least four extra satellites and preferably six, if the budget can be found, to create a robust system that can provide disaster communications as well as high-accuracy positioning services, according to working group member Kazuto Suzuki.
“This is not a headline grabber. This is real,” Suzuki said April 26. “The mission is to redefine the objective of QZSS … to a national project for sovereign rights for positioning and navigation.”
The Quazi-Zenith system calls for placing satellites in highly elliptical orbits to rebroadcast enhanced GPS navigation signals to hard-to-reach areas in Japan, such as urban canyons and mountainous terrain.
Last September, Japan launched its first Quasi-Zenith satellite, a technology demonstrator called Michibiki. Built by Mitsubishi Electric Corp. based on the company’s commercial DS2000 frame, Michibiki is finishing on-orbit testing, according to the Japan Aerospace Exploration Agency. A minimum of three satellites are required for round-the-clock coverage.
The working group recommended Japan launch the constellation in two stages, Suzuki said, with the first stage consisting of three additional satellites launched into elliptical orbits. In the second stage, three more satellites would be launched into geostationary orbits.
“The core question is whether Japan will have autonomous capability even if GPS is shut down for technical or political reasons,” Suzuki said
Suzuki said the working group’s decision should help break a series of administrative logjams that have held the system back for nearly a decade as the private sector and several government ministries argued over who was to control and fund a Japanese GPS system. In a 2007 compromise, it was agreed that the government would pay for the development, launch and test of one satellite, and postpone a decision on who would pay for and control a to-be-determined number of satellites until after the test satellite proved successful.
This spring’s recommendation comes at a time when Japan has become more aware that QZSS is not just a funding football but an essential part of the nation’s strategic infrastructure, Suzuki said.
“In order to secure the autonomy of our navigation, and ensuring our national sovereign rights, the QZSS should be formed by seven satellites,” he said.
Suzuki said the QZSS also has been given added impetus by the growing awareness of the need for Japan to improve its disaster response capabilities following the March 11 earthquake and massive tsunami that overwhelmed the sea defenses of hundreds of kilometers of the Pacific coastline of northeast Japan, leaving more than 27,000 killed or missing.
The working group has recommended the development of special GPS-compatible electronic chips that can be put in mobile phones to create a short message service function at the very least, Suzuki said.
“So if, for example, a person has a mobile phone and is trapped under the rubble, they can send a message via QZSS to give their location,” he said.
In an April 25 email interview with Space News, SHSP Secretary General Hiroshi Yamakawa stressed that the recommendation was not a final step, but an important one that would inform several higher-level committees that will discuss the proposed configuration by the end of August for the following year’s budget. A final decision on the exact configuration will come in December, he said.
“It is correct to say that the [working group’s] decision is provisional, but it will be the most important element to make the final decision,” said working group member Satoshi Tsuzukibashi, who also is director of the Office of Defense Production Committee at the Japan Business Federation.
Tsuzukibashi said April 26 that the working group was recommending that Japan aim for a constellation of seven satellites that would enable the system to work seamlessly and provide greater positioning accuracy.
Launching and maintaining such a system would cost in the region of 230 billion yen ($2.8 billion) during the next decade, he said.
To save money, the SHSP may consider using a non-Japanese launcher, Suzuki said. “The question of cost includes the questions of launcher,” he said. “H-2A is too expensive, so there is the possibility that QZSS will be launched by some cheaper launcher, perhaps Russian ones. There is no decision yet, and it will be negotiated between SHSP and the Ministry of Finance.”