Turning GPS off during a crisis would just turn that crisis into a disaster. Pretty much the whole world now relies on GPS for precision timing, and many systems would shut down soon after it disappeared.

MG23: I was at the ICAO meeting when the MoU was signed between the US and ICAO at the end of the 90's. the clause was there.
Since then there has been in 2007 a declaration during an ICAO assembly by a US rep that said :


The reasoning was at the time that the US could not accept that " forgein hostile forces " use GPS to guide weapons aimed at their own troops.
This clause was also used to obtain funding for Galileo in Europe.

As far as I know ( and I welcome if someone here can correct me( the clause is still there. Everybody hangs on the 2007 declaration but GPS is still owned by the US military ( although managed by a joint US military/ civil body)
Interesting is what is written on the gps.gov web site FAQ :

Hopefully you do fly an Embraer in a potential "Regional denial part of the world " .

Couldn't known positions of Navaids like VORs be used as a reference, to cross-calibrate any nav equipment on board at any time even without a valid GPS signal? That should be good at least for IFR and non precision approaches.

Obviously they can shut GPS down. Equally obviously, it would be a disaster as many essential IT services around the world that use it for precision timing shut down within minutes to hours.

And pointless now there are a couple more systems that will work just as well as GPS for targeting bombs.

Less Hair: The problem is not nav precision, it is the yaw damper. No yaw damper means no autopilot, which means no RVSM.
AHRS-only arcraft with no GPS signal can still use air data, magnetometers and DME/DME autotuning to determine the aircraft's position.

Has the US military ever given a guarantee to civilian users that their GPS will work at any time? Guess no. How could certified systems onboard commercial aircraft/private jets be made dependent on working military GPS then?

Back to sleep, it's all been cancelled.

Until the next time...

selective availability did not shut GPS down, it was simply less accurate.

Folks,
There is a feature article on GPS vulnerability in the latest Aviation Week, including pointing out the easy availability of cheap hand held jambers and spoofers.
Given that Airservices Australia's plans will result in us being far more dependent on GPS than any other country, it is "food for thought".

MG23 :True but think how many last generation GPS dependent US manufactured weapons were given freely to or "taken" by now hostile forces . Think Afghanistan, Iran, Iraq Syria, Libya, African rebel groups of all kind , etc...
I read even that recently quite a few last generation US tanks given to Iraq forces have now been taken over by ISIS, and that the same models are fighting each other in Faluja.
If you were a US military and someone was targeting your forces with one of those and you had a possibility to switch their precision off , would not you do it ?

GPS was primarily a military guidance system ( just like ORAN-C was) they allow civilians to use it but things like IT clocks synchronization of Embraer Yaw dampers was not what they had in mind when designing it.

Why do you think we Europeans spend billions developing Galileo ?

Will Galileo have a guaranteed civil availability at any time?

Galileo is a civil system European Space Agency and EU have funded it. So that would indicate it is intended for civil use. One of the reasons it was initially planned was the potential unforecastable loss of GPS precision due to a US government action.

Looks like the UK MoD are having jamming exercises in July.


GPS jamming exercises | Ofcom

New FAA notice just issued for Las Vegas GPS Interference Testing, June 18.

https://www.faasafety.gov/files/noti...t_Advisory.pdf

Adolescent response at best, and totally off topic.

Given that Australia has traffic levels 1/20th of those of the USA (isn't that right, Leddie), and that Australia has a comprehensive Backup Navigation Network based on ground-based navaids, including ILSs, if the Navstar system went down, there should be no major problem getting back on the ground. As said above, if Navstar fell over, the world would stop, not just a few Aussie aeroplanes...

Although multi-standard systems are safer than single-standard , one can presume that in the event of a "warm" conflict eg. Ukraine, electronic warfare would make civiilan navigation systems the first casualty.

Whether at some point during a "warm" conflict some clever and deniable kid in Maryland will propose making team red's presidential aircraft or even a tourist craft land 100 feet under the tarmac is a different question; I am sure that neither Boeing nor Airbus like the idea, as once this bell has been rung it can never again be unrung.

Another good reason for having two pairs of trained Mark I eyeballs sitting at the pointy end of the aircraft instead of Roby McRobot.

The EC-130H Compass Call aircraft can listen to communications traffic (analog and digital) and jam almost every type of signal from VHF to radar frequencies. So there goes your cell phone, wifi and GPS within a 10 mile radius.

Perhaps the jamming exercise is intended to secretly test backup systems of major infrastructure?