美政府報告警告 GPS系統將於2010失效

美政府報告警告 GPS系統將於2010失效
在美國審計辦公室(GAO)所撰寫的報告中提及,由於GPS管理不善及欠缺維修而令衛星出現老化及失效問題,短時間內難以有新的衛星可代替。

報告更指出,如果空軍不在限定時間內開發出GPS IIIA 衛星,若有效的GPS衛星群總數低於美國政府承諾的GPS全球定位服務所需的最低衛星數目時,受影響的GPS用戶除了各大用戶外,也包括了軍方。所以大家請不要依賴 GPS,學看地圖吧!(這是那麼多車子扔進河流的原因嗎?)
http://chinese.engadget.com/2009/05/22/gps-2010-die/

GPS System Could Begin to Fail Within a Year
David Coursey, PC World | Tuesday, May 19, 2009 7:11 AM PDT

The Global Positioning System faces the possibility of failures and blackouts, a federal watchdog agency has warned the U.S. Congress. Mismanagement by and underinvestment by the U.S. Air Force places the GPS at risk of failure in 2010 and beyond. The problem: Delays in launching replacement satellites, among other things.

According to the Government Accountability Office report, "In recent years, the Air Force has struggled to successfully build GPS satellites within cost and schedule goals" as part of a $2 billion modernization program.

"If the Air Force does not meet its schedule goals for development of GPS IIIA satellites, there will be an increased likelihood that in 2010, as old satellites begin to fail, the overall GPS constellation will fall below the number of satellites required to provide the level of GPS service that the U.S. government commits to."

Considered by the GAO to be "essential to national security" the GPS is also widely used by business and consumers and is a driver for next-generation location-based mobile applications used with smartphones and other devices.

"Such a gap in capability could have wide-ranging impacts on all GPS users," the GAO report states, "though there are measures the Air Force and others can take to plan for and minimize these impacts."

It is hard to imagine the U.S. government could allow this to happen. Actually, that's a lie, it's easy to imagine, but there is also time for corrective action to be taken. The first replacement satellite is expected to be launched this November, some three years after the original launch date. Speeding up future launches can solve the problem, but is likely to come at a high price.

The American GPS, though the pioneering consumer satnav system, is not alone. Russia, China, and India each have systems of their own, which are being expanded.

The European Union's Galileo system, intended as a rival for GPS, is expected to begin its rollout later this year.

The delay and potential failure of GPS gives these other nations the potential to rival the U.S. in space, something the U.S. government is unlikely to accept. The report is a black eye for the Air Force, which developed the GPS system during the 1980s and has maintained it since.
http://www.pcworld.com/businesscenter/article/165126/gps_system_could_begin_to_fail_within_a_year.html

Air Force Responds to GPS Outage Concerns

The sky isn't falling and neither is the Global Positioning System, the U.S. Air Force said during a Twitter news conference. "No, the GPS will not go down," tweeted Col. Dave Buckman of the Air Force's Space Command. "GAO points out, there is potential risk associated with a degradation in GPS performance."

"The issue is under control. We are working hard to get out the word. The issue is not whether GPS will stop working. There's only a small risk we will not continue to exceed our performance standard," the Air Force official said.

The tweet forum marked the first time Space Command has used its Twitter page for a scheduled forum. During the session, held Wednesday afternoon, the Air Force sought to allay fears raised by a Government Accountability Office report critical of its management of the GPS program.

"Agree w/ GAO thr's a potential risk, but GPS isn't falling out of the sky--we have plans 2 mitigate risk & prevent a gap," the Air Force officials said, in the clipped 140-character cadence of Twitter conversation.

The GAO report predicated only an 80 percent likelihood the Air Force would be able to maintain the full 24-satellite constellation over a period between 2010 and 2014. Going below 24 satellites could result in lower GPS performance, GAO said.

The danger of a GPS outage, though small, exists if the Air Force is unable to improve its satellite replacement program. Currently years behind, Space Command says it has plans to launch enough satellites to keep the constellation above the 24-satellite threshold.

"We have 30+ satellites on orbit now. We'll launch another in Aug 09, and again early 10. Going below 24 won't happen," the Air Force said, counting on an improvement in its ability to get satellites into space.

"We definitely need to keep this in perspective. Since 1995, GPS has never failed to exceed performance standards."

Delays in the $5.8 billion program have occurred for a variety of reasons, the GAO report stated. Among them is consolidation among companies that supply GPS hardware to the Air Force.

GPS vendors have, not surprisingly, also said the reports of GPS' possible demise have been overblown. Some customers have expressed concern over whether it is safe to invest in GPS devices and vendors have been quick to offer reassurance.

Bottom line: The Air Force says everything is covered, but if that had been true all along this flap would not have occurred. Because GPS is considered vital to national security, plus its wide use by business and consumers, it is reasonable to expect whatever funds necessary will be spent to keep GPS as operational as possible.

The Air Force's confident response is reasonable enough, but believing it requires at least a small leap of faith by GPS users.
http://www.pcworld.com/article/165305/air_force_responds_to_gps_outage_concerns.html

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