GPS faces shutdown

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retsina

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There is a write-up in July's Yachting Monthly with the title "GPS faces shutdown".

According to the US government the GPS could begin to deteriorate in 2010 resulting in blackouts or inaccuracies; the problem appears to be lack of investement in maintaining the satellites.

I'll get my old sextant out and get it ready...
 
So, maybe an increase in demand for those who can still 'cut the mustard' with a pencil, a calculator and an EP.

I happen to know a traditionally-skilled pro nav who can do it all without any need for 'lectronix. Been unfashionable for a while, but.....

...taking bookings for next summer now!

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there's a new European system coming....anyway the Americans need it for there military...no?

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Sign of the times, methinks. The US is broke and can't maintain it's primary navigation system. They certainly aren't going to find the money for the sake of us boaty types.

GPS is good stuff but we may have to pay for it the in future.
 
I haven't seen the YM article, but if you read the official report from the GAO, it gives about an 80% chance of making it through to 2014 with more than 24 satellites, and about a 99% chance of making it through to 2014 with at least 21. (There are 31 up there at the moment, but we only need 24)

So GPS is hardly likely to "crash and burn" in the next five years. The problem comes in the following five years, where there is only a 10% chance of maintaining the 24-satellite system, and a 50/50 chance of maintaining 21 satellites.

The problem seems to have nothing to do with money (the USAF have committed to buying the satellites) but everything to do with mismanagement. The latest crop of replacement satellites should have been launched three years ago, but the first one isn't likely to be launched until this November. And the Block 3As that were supposed to be ready for launch in 2014 have only just been ordered. *If* they are ready in time, the problem goes away -- but the GAO's best guess is that they are likely to be two years late -- and that's why there might be a problem.

But it's more likely to affect land navigators than sea navigators, because sea navigators at least have a clear view of the sky. That's why we were the guinea pigs for civilian GPS, back in the early nineties before the GPS constellation was complete. And at least this time we don't have so-called "selective availability" to contend with.

Plus thre's the fact that the Russian system (Glonass)is almost certain to be giving us 24/7 worldwide coverage within the first few weeks of next year, if any manufacturer cares to produce civilian receivers at sensible prices.
 
Bit of scaremongering - this story pops up from time to time.
Just like the Daily Mail headline about an EU ensign.

It's true that the quality will 'degrade' somewhat over the next few years, but whether GPS is accurate to 1.5m or 2.0m seems a bit academic to me. There's always Eyeball Mk I and paper charts.

Makes you wonder though - the US has always been vehemently opposed to the independent EU Galileo system. One of the arguments was that GPS was perfectly adequate ...
Something the EU did/is doing that will actually be of use to the ordinary boater - whatever next? Bet this does not warrant a Daily Mail headline /forums/images/graemlins/tongue.gif
 
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No the military use a more accurate system.

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To be correct the same satelites transmit 2 signals - one encoded for military, other open for public use. Therefore if a sat goes down - it's both users suffer.

But anyway - the system has spare sats in orbit that only need 'switch-on' in event of needing to replace a duff sat. Redundancy is already built in.

As I understand it - the real problem lies in sat launching and maintenance of ground stations more than the sats themselves. And as it's so important to so many countries and users as well as US Military - I don't really think it will be that bad ... IMHO it's a juicy story for media to hook into and elaborate ..
 
It would be a good thing if the signals were only accurate to 100 meters or even less.People tend to rely far too much on GPS .A friend of mine says one shouldn't have to know astro anymore because it is redundant.He uses his plotter to enter unknown harbours in fog and the like.I just hope he doesn't get it wrong one day.
 
Lets face it, a triangle of probablility less than half a mile wide was reckoned to be pretty good before epf came aboard. Modern GPS is absolutely fine for navigation in bad visibility - and given the need to enter an unknown harbour in fog is a great deal safer than estimating (qv guessing) where you are.

GPS plotting is a basic navigation tool which no boat should be without nowadays, but should always be backed up with paper charts and compass against seawater getting in to the elctronics or whatever.
 
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No the military use a more accurate system.

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To be correct the same satelites transmit 2 signals - one encoded for military, other open for public use. Therefore if a sat goes down - it's both users suffer.


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In fact, originally, the less accurate system, known as the Coarse Acquisition system, was used to facilitate the lock on the encrypted system. So they couldn't turn it off without losing their more accurate system.

I suspect that now, with rather more sensitive electronics being available, they probably don't need to jump through this hoop any more.
 
A friend was telling me the other day of going crabbing with his grandfather (in a boat that I now own).

They went out into thick fog with nothing but a box compass (right next to the big lump of iron that is a Lister engine!). He was able to navigate straight to each string of pots, then back into the Cove again without ever getting sight of land.
 
The GAO report is publicly available on http://www.gao.gov/new.items/d09670t.pdf.

Of course you need to read the whole thing to get all the detail, but the first sentence sums it up rather neatly:

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It is uncertain whether the Air Force will be able to acquire new satellites in time to maintain current GPS service without interruption. If not, some military operations and some civilian users could be adversely affected.

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So (1) it's not a media-generated story, and
(2) it's cause for concern rather than alarm.

Dropping a few satellites -- even if we lose *all* the oldest ones, and go down to 18 or so -- probably won't make much difference to marine users, who generally don't need high accuracy, and who can generally "see" all the satellites that are above the horizon. But it could affect land users, whose "view" of the sky is limited by buildings or trees, and for whom a crosstrack error of a few metres could put them on the wrong road, or make a train stop with its doors just past the end of the station platform, or make a farmer double-dose insecticide on some bits of a field and miss other bits completely.
 
According to the Galileo Wikipedia, they have now agreed to get the system fully operational by 2013 which should solve the problem?
It mentions that the Galileo system will be interoperable with the US GPS system...........so does this mean that we can use our existing GPS sets.....?
 
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.......so does this mean that we can use our existing GPS sets.....?

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No. It means that if we want to use Gallileo we will need to replace existing recevers with ones capable of tracking GPS, Gallileo (and Glonass) satellites.
For high precission applications we are already using receivers that track both GPS and Glonass. The big benefit is the increased number of available sats and the reduced risk of problems with the anticipated GPS shortfall.
 
Glonass - that can be ignored basically as it is still re-aimed for Russian conflict areas such as Chechen and Balkans. It also is not fully implemented, being a casualty of Russian failure to keep Military Funding going.
 
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Glonass - that can be ignored basically as it is still re-aimed for Russian conflict areas such as Chechen and Balkans. It also is not fully implemented, being a casualty of Russian failure to keep Military Funding going.

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Not totally true. Glonass currently has 17 operational satellites in orbit with more scheduled to be launched. I was not suggesting that it was a standalone alternative to GPS, just that its signals can be used to suppliment those of GPS.

Currently in Oslo, with an elevation cut off of 10 deg., I can see and use 9 GPS and 6 Glonass. If I raise the elevation mask to 30 deg. which is not unrealistic onshore, I can see 5 GPS and 3 Glonass.

All we need is a low cost receiver capable of tracking and computing position using both. Unfortunately current survey grade receivers able to do this cost $15,000!
 
OK it's useable but you like I am in good position to use ... but Russia does have aligned more for conflict areas .. that was done when Chechen flared up. Various web-sites highlight this. Even dear old Wikipedia.
As you confirm - it is not fully operational - coverage is fragmented while awaiting further launches.

Some peeps don't know that there are more sytsems up there ... USA, Europe (Galileo), Russian (GLONASS), Indian, Japanese ... USA of course being the most comprehensive coverage so far.

One day maybe someone will produce a retail machine at sensible price to use all or at least some of above ..instead of just one.
 
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One day maybe someone will produce a retail machine at sensible price to use all or at least some of above ..instead of just one.

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Unfortunately that will probably not happen before there are several Gallileo satellites operational. One of the complications that makes Glonass / GPS interoperability complex is that the former uses FDMA (Frequency Division Multipe Access) while GPS (and Galilleo) use CDMA (Code Division Multiple Access). There are plans for a new generation of Glonass-K satellites to switch to CDMA but that wont happen for a few years yet.
 
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