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.
　日本版のＧＰＳ（全地球測位システム）整備を目指した人工衛星の１号機「みちびき」を、宇宙航空研究開発機構などが打ち上げた。

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.
　カーナビゲーションなどで位置確認に使われているＧＰＳの測位誤差を、現在の１０メートル程度から１メートル以下に改善することを目指し、産官学で技術実証試験に挑む。

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.
　人工衛星を使った測位技術関連の製品、サービスは、国際的に市場が拡大している。世界に伍(ご)していける成果を期待したい。

Fifty-eight different tests are planned. The success or failure of the project depends on how its high positioning accuracy can be utilized.
　試験は５８テーマが予定されており、高い測位精度をどう生かせるかが、成否のかぎとなる。

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.
　その一例が、除雪車や耕運機などの自動誘導だ。誤差が１０メートルでは道路の除雪はできないし、畑も耕せない。誤差が１メートル以下なら、それが可能になる。

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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.
　すでにＧＰＳは、山岳遭難の救助からデジタルカメラのような日用品まで幅広く使われている。カメラの場合、撮影場所が写真に自動で付加されるため、旅行の記録になる、などと人気がある。

Improvement of GPS accuracy will stimulate further growth in such existing fields.
　精度の向上は、こうした既存分野も活性化させるだろう。

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.
　みちびきの特徴は、その軌道にある。地上から見ると、日本を含む西太平洋上空を「８の字」を描くように２４時間で飛行する。

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.
　うち８時間程度は日本上空にいるので、３機あれば常に１機が日本のほぼ真上に見える。このため衛星からの電波は、ビルや山など障害物にほとんど遮られない。

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.
　米国が運用する今のＧＰＳは衛星約３０機で地球全体をカバーしている。だが、都市部や山間部では十分な信号強度が得られない。

Additional transmissions from Michibiki, which will often be nearly overhead in Japan, will enhance positioning accuracy.
　これに、みちびきの電波を加えることで測位精度を上げる。

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.
　問題は後続の衛星だ。みちびきは４００億円、その後の衛星も１機３５０億円程度と試算されている。決して安くはない。実用化には最低３機が必要で、官民の費用分担を巡り論議が起きている。

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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.
　政府は関係省庁によるチームを設け、今年度末までに後続機のあり方を検討するという。その際には国際動向、日本の安全保障も十分考慮せねばならない。

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.
　もともとＧＰＳは、米国が軍事用に開発した。いつ運用が制限されるかわからない。そうした懸念から、欧州、中国、インドは独自の測位システムを構築中だ。ロシアは安全保障、防衛のため自前のシステムを運用している。


The United States, China and Europe are moving toward cooperation with each other on positioning technology.
　欧米、中国などが測位技術で連携する動きもある。

Against such a background, Japan must work out a GPS strategy that will take advantage of its technology while maintaining its international voice.
日本が国際的な発言力を保ちつつ、技術を生かせる戦略が求められる。

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