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Some news reports have been more measured:




;-)

Quoting frankreed@HistoricalAtlas.com:

>
> I've read the GAO report all the way through and also the Air Force replies on the
> matter. I think this issue has been over-blown by the media. They're quoting the
> first page summary of the report, and like most GAO reports, it's intentionally
> dire.
>
> For marine navigation, the potential reduction in active GPS satellites is not likely
> to be noticeable. Marine users have the best conditions for GPS signal acquisition.
> From a boat at sea, a GPS receiver can generally "see" the whole sky and reduced
> numbers of satellites will rarely matter (unless there is a major program delay, see
> below, which would not have a practical impact until about 2014).
>
> The one market that may be adversely affected, sooner rather than later, is "urban
> canyon" navigation since those users benefit most from the excess satellite capacity
> which currently exists (far from being in trouble, the US GPS constellation currently
> has EXCESS capacity). These are the car navigation and mobile phone location
> services, for example, which are becoming dramatically more popular with each passing
> year. Since these services are already impaired in environments like this where GPS
> signals propagate poorly, if at all, this report will probably encourage more rapid
> adoption of alternative location services like SkyHook (that's the one based on
> triangulation of home and business Wi-Fi signals). The challenge is to make the
> hand-off between GPS and other services seamless and invisible to the end-user.
>
> There are two issues raised in later sections of the GAO report which are serious and
> more relevant than the supposed increased risk in 2010. The first of these is the
> potential decline in service that could result if there is a serious delay in the
> launches of the next series of satellites, the GPS-III satellites. If they're delayed
> by two years, then there could be a serious disruption in the US GPS signals starting
> around 2014 and lasting for as long as seven years. Have a look at figures 4 and 5 in
> the GAO report. Although GAO reports are intentionally pessimistic, I believe that
> the low probability of having a full GPS constellation around 2017 is realistic. That
> is, it's realistic IF there is a significant delay in the GPS-III program. But note
> that the EU's Galileo system as well as the Russian GLONASS systems are expected to
> be fully operational in this period. So this isn't an issue for global navigation
> directly; it's an issue for US-pre-eminence in the satellite navigation business, and
> it's an issue for the US military which would be loath to rely on a non-US
> position-finding system. Beyond the specifics of the GAO report, the US Air Force
> claims that they already have procedures lined up which would extend the lives of
> existing satellites (mainly by powering down other military hardware on the
> satellites) and so even this supposed gap could potentially be covered.
>
> The second significant problem outlined in the GAO report applies only to the US
> military. They haven't funded receivers to take advantage of the new satellites'
> capabilities. There are details in the report.
>
> To sum up, the "sky is falling" media reports are misleading. The GPS system is not
> on the verge of failure in 2010. However, it is on the verge of disappointing, to
> some extent, the rapidly growing commercial market for its services in urban areas
> because the current excess capacity is considered temporary, and there are some
> significant issues for the US military. So unless there is some major collapse in the
> system unrelated to the issues in the GAO report, there do not appear to be any
> significant issues for marine navigation with the single exception that marine users
> may need to upgrade to systems capable of picking up signale from multiple satellite
> constellations (GPS, GLONASS, Galileo, Beidou/Compass) at a somewhat earlier date
> (c.2014) if the worst predictions in the GAO report are borne out.
>
> -FER
> PS: There are a couple of distinct reports on GPS from the GAO. The longer of them is
> linked here.
> 
File: 

   

>
>
> >
>


===============================================================================
 Richard B. Langley                            E-mail: lang@unb.ca
 Geodetic Research Laboratory                  Web: http://www.unb.ca/GGE/
 Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506 453-5142
 University of New Brunswick                   Fax:      +1 506 453-4943
 Fredericton, N.B., Canada  E3B 5A3
     Fredericton?  Where's that?  See: http://www.city.fredericton.nb.ca/
===============================================================================



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