Japan must map out its own GPS strategy

The Yomiuri Shimbun (Sep. 21, 2010)
Japan must map out its own GPS strategy
衛星みちびき 日本版GPSの戦略作り急げ(9月20日付・読売社説)

Japan's first navigation satellite, Michibiki, aimed at improving the global positioning system's coverage of Japan, has been launched by the Japan Aerospace Exploration Agency.

The project--undertaken jointly by the industrial, public and academic sectors--calls for technology verification tests and is aimed at reducing the margin of error of GPS devices used in car navigation and other services from the current 10 meters or so to less than one meter.

The market for satellite-based GPS products and services has been expanding globally. We hope that the Michibiki project will bring about results that make Japan more competitive in this area.

Fifty-eight different tests are planned. The success or failure of the project depends on how its high positioning accuracy can be utilized.

One example is a proposed guidance system for unmanned snow removers and farm machinery. Neither snow removal from roads nor soil cultivation in fields can be done if the machines are allowed to drift as much as 10 meters off course. Both can be done only when the margin of error is held to less than one meter.


Diverse applications

GPS has been widely used in a diverse range of fields from rescue operations in alpine accidents to consumer products such as digital cameras. Such cameras are popular because locations where photos are shot are automatically stored for use as travel records.

Improvement of GPS accuracy will stimulate further growth in such existing fields.

A hallmark of Michibiki lies in the orbit it takes. Michibiki flies in an asymmetrical figure-eight course above the western Pacific, including Japan, every 24 hours.

Michibiki's flight above Japan accounts for about eight hours of each orbit. If three satellites like Michibiki were put into orbit, at least one would be above Japan at all times. Because GPS satellites rely on line-of-sight radio wave transmission, this would nearly eliminate the problem of signals being blocked by obstacles such as buildings and mountains.

The GPS currently uses about 30 U.S. satellites to cover the entire globe. Accurate results depend on devices on or near the Earth's surface being able to compare signals from four satellites in the visible sky. The system can fail in urban and mountainous areas where the lower portions of the sky are blocked by mountains or buildings.

Additional transmissions from Michibiki, which will often be nearly overhead in Japan, will enhance positioning accuracy.

The problem is how to secure funding for the satellites that are meant to follow Michibiki. It cost 40 billion yen to build Michibiki. The cost for similar following satellites is estimated at a hefty 35 billion yen each. At least three satellites are necessary to commercialize the enhanced Japanese version of the GPS system. Discussions have begun about how to divide costs between the public and private sectors.


A project team planned

The government says it will establish a project team comprising officials from the ministries and agencies concerned to study how to pay for the satellites that will follow Michibiki by the end of the current fiscal year. In that instance, the government must give due consideration to international trends and Japan's security interests.

The GPS was developed by the United States, originally for military purposes. It remains to be seen whether its use may be restricted in the future. Out of such concern, China, India and European countries are building their own positioning systems. Russia operates its own system for the purpose of ensuring security and defense.

The United States, China and Europe are moving toward cooperation with each other on positioning technology.

Against such a background, Japan must work out a GPS strategy that will take advantage of its technology while maintaining its international voice.

(From The Yomiuri Shimbun, Sept. 20, 2010)
(2010年9月20日01時20分 読売新聞)

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