Could the Americans switch off GPS ?

[Sybarite]

The short answer is yes but they won’t, at least not yet, because they need it for their own military purposes.

I was speaking today to Dr Mike Simpson :

http://swfound.org/about-us/our-team/dr-michael-k-simpson/

husband of a former lady Pastor at our church, and former President of the American University of Paris.

However, the development of Galileo is being carefully watched because, today you can hook onto up to 11 satellites which produces positions accurate to 10cm. Another four satellites need to be positioned before Galileo come on-line, possibly next year.

The Americans can however shut down the civilian applications of GPS but it’s highly unlikely they would, IHO.

 

[MASH]

There's a very great deal more to why this is not an option than "their own military purposes", that's pub talk.

I don't know what you mean by "shut down the civilian applications of GPS" - how is it possible to selectively prevent civilians receiving a radio signal? Clearly it isn't.

GPS is embedded in every aspect of our lives, the world's economy would quite literally come to a full stop without it. Switching it off is not an option and they've said so. Many times.

There's nothing to see here. Move along!

 

[marklucas]

GPS broadcasts on 2 frequencies in the 1.2 and 1.5 GHz bands. Civilian receivers only receive on the 1.5 GHz band - military receivers receive on both. The reason there are two frequencies is to mitigate the effects of frequency specific fading due to atmospheric conditions.

At the flick of a button the US could quite easily turn off the 1.5 GHz signal or re-apply selective availability to any level they chose (which is how it used to be so accuracy ~100m).

Remember GPS is a military system being used by civilians - at least Galileo is an openly funded public project with clear civilian based objectives e.g. landing planes.

 

[Sybarite]

There's a very great deal more to why this is not an option than "their own military purposes", that's pub talk.

I don't know what you mean by "shut down the civilian applications of GPS" - how is it possible to selectively prevent civilians receiving a radio signal? Clearly it isn't.

GPS is embedded in every aspect of our lives, the world's economy would quite literally come to a full stop without it. Switching it off is not an option and they've said so. Many times.

There's nothing to see here. Move along!

Perhaps you didn't read my informant's cv?

 

[l'escargot]

They would need some serious justification to ground the world's commercial airline fleet and dock the world's merchant navy...

 

[Buck Turgidson]

They would need some serious justification to ground the world's commercial airline fleet and dock the world's merchant navy...

and the SOLAS services that currently use GPS.

It would be akin to manslaughter which is why it won't happen.

 

[Phoenix of Hamble]

They would need some serious justification to ground the world's commercial airline fleet and dock the world's merchant navy...

That and shut down every major data centre on the planet, thus bringing the internet, and every corporate on the planet to a crashing halt....... I suspect its a tincey wincey bit unlikely....

 

[Sandy]

and the SOLAS services that currently use GPS.

It would be akin to manslaughter which is why it won't happen.

Bovine excreta, if a nation can go to war it can turn off GPS after all it is just an aid to navigation.

 

[onesea]

They would need some serious justification to ground the world's commercial airline fleet and dock the world's merchant navy...

I doubt they would stop the merchant fleet the ship owners would just point out to the Captains they had sextants and use them... One or 2 more ships would end up on beaches etc... Hey people on here would just say are they professionals or not?

That and shut down every major data centre on the planet, thus bringing the internet, and every corporate on the planet to a crashing halt....... I suspect its a tincey wincey bit unlikely....

There is a point there don't banks use GPS time signals as part of there banking progress to record when transactions take place between stock exchanges?
Still think a full outage is unlikely although I am sure there are more games the controllers can play then we know about...

 

[Beadle]

They would need some serious justification to ground the world's commercial airline fleet and dock the world's merchant navy...

I don't know about airlines, although they were flying all over the world before GPS - so one would expect them to have alternative methods.

Certainly shipping would be able to continue - even if it was back to sextants. Not sure if Loran is still working - if it is that's adequate - you don't really need 10m accuracy on a ship.

Data centres would be largely unaffected - there are plenty of other atomic clocks that they can sync to apart from GPS.

Having said that I can't see why the US would turn it off - it would handicap their military more than anyone elses.

 

[chinita]

Perhaps you didn't read my informant's cv?

I did. Not particularly impressed. He is an academic.

If anybody knew the true story, they would not be telling you and you would not be passing it on to the likes of us.

 

[Seajet]

In the early days of GPS the Americans did use ' selective ability ' to degrade the accuracy for civilians or knobble it entirely when the Gulf Wars were going on; there were stories of yachts being surprised to read that they were doing 400 knots at 10'000 feet !

However I understand that since GPS became so popular and a major safety aid, the U.S. put out an official statement a few years ago saying they will not spoof the system.

Having said that, I know what I'd do if I was in Washington with news that an amateur GPS guided terrorist missile was heading my way !

 

[Phoenix of Hamble]

Data centres would be largely unaffected - there are plenty of other atomic clocks that they can sync to apart from GPS.
.

Not that can be timed accurately.... atomic clocks are great.... but are on the network, with therefore unreliable certainty over latency.... only any use if they are local... and too many aren't, so would cause an avalanche of outages that would eventually take everything down... very few telcos for example now have their own clocks, so all bandwidth (inc telehouses with core traffic switching) would probably fall over fairly quickly.

 

[Buck Turgidson]

Bovine excreta, if a nation can go to war it can turn off GPS after all it is just an aid to navigation.

It's not just an aid to navigation in the aviation world. There are categories of approach which are only available using GPS. ICAO have mandated that those approaches should be available for every runway by 2016 and they are already implemented in many many remote places as the only approach. For en-route navigation it would restrict many areas of airspace and the entire airbus fleet would be restricted in how they are operated due to their GPS primary architecture. The EGPWS system which helps prevent CFIT will not work without GPS. So you would be sending aviation back 20+ years. Ronnie made GPS available to civvy operators because of the Korean Airlines shoot down. Subsequently the yanks have declared that they will not degrade the system which is why transport systems have been developed which rely on it.


http://www.gps.gov/policy/

 

[lustyd]

Not that can be timed accurately.... atomic clocks are great.... but are on the network, with therefore unreliable certainty over latency.... only any use if they are local... and too many aren't, so would cause an avalanche of outages that would eventually take everything down... very few telcos for example now have their own clocks, so all bandwidth (inc telehouses with core traffic switching) would probably fall over fairly quickly.

Incorrect. Most computer systems will run fine with the wrong time - I see it often, especially on networking kit such as switches and routers. Active directory (and Kerberos) fails if the time on the client is over 5 minutes different from that of the server, but I have seen these months out from real time (with all local systems agreeing to the error) yet still merrily working on the internet with other systems. Certificates will fail if their creation time is in the fututure. Bank transactions will be problematic if the time is massively out, but even a man with a wrist watch can set the network clock once a day and achieve enough accuracy to keep things going since binary drift is less of a problem than it was in the 1990s (modern OSs can ask the RTC every now and then if necessary). Worst case, if GPS was switched off anyone relying on time would add in a radio time PCI card within a few days to fix the issue.

 

[lustyd]

It's not just an aid to navigation in the aviation world. There are categories of approach which are only available using GPS. ICAO have mandated that those approaches should be available for every runway by 2016 and they are already implemented in many many remote places as the only approach. For en-route navigation it would restrict many areas of airspace and the entire airbus fleet would be restricted in how they are operated due to their GPS primary architecture. The EGPWS system which helps prevent CFIT will not work without GPS. So you would be sending aviation back 20+ years. Ronnie made GPS available to civvy operators because of the Korean Airlines shoot down. Subsequently the yanks have declared that they will not degrade the system which is why transport systems have been developed which rely on it.


http://www.gps.gov/policy/

Are you saying that during a global GPS outage that planes would be forbidden from landing rather than allow pilots to take control like in the good old days? Seems rather pointless making sure a pilot can land a plane manually during training if that's the case...

 

[interloper]

Being able to switch off civilian GPS was a handy weapon at one time, but no longer offers any tactical advantage now that similar Russian and European Union systems are (or soon will be) available.

 

[GrahamHR]

Will existing GPS receivers be able to use Galileo satellite signals, or will we all have to buy new receivers ( when the existing GPS satellites die, rather than being switched off, which is unlikely)

 

[Buck Turgidson]

Are you saying that during a global GPS outage that planes would be forbidden from landing rather than allow pilots to take control like in the good old days? Seems rather pointless making sure a pilot can land a plane manually during training if that's the case...

Visual approaches are only useful in visual conditions. GPS or more accurately GNSS approaches are used in Instrument Metrological Conditions. i.e. when it's cloudy ;-)

 

[lustyd]

Visual approaches are only useful in visual conditions. GPS or more accurately GNSS approaches are used in Instrument Metrological Conditions. i.e. when it's cloudy ;-)

So you're saying planes used to crash when it was cloudy? I'm pretty sure any reasonable pilot would have a good plan even in fog to avoid their own demise.