GPS Down

[boofhead]

Is the upcoming GPS outage in the US a military shutdown or solar flare forecast?
Any reason given?

[archae86]

What source has distributed the outage prediction to you? Your phrasing suggests a global system outage, but this web page, which shows historic and forecasted outages, shows 30 healthy satellites at the moment, and only single satellite outages in the near-term forecast.

GPS outage information page (http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx)

Localized outages can be arranged at need by what amount to jamming techniques.

[boofhead]

https://pilotweb.nas.faa.gov/PilotWeb/noticesAction.do?queryType=ALLGPS&formatType=DOMESTIC

[pattern_is_full]

NOTAMs are for a pretty specific location - coincidentally centered on Holloman Air Force Base and the White Sands Missile Range.

So I'd guess local interference from some "project" going on there, rather than a cosmic event.

[westhawk]

Looks like sats out of service. KNMH is the location given for all GPS sat outages and PRN (pseudo random noise) 25 apparently refers to a particular sat. The NOTAMS below that that appear to be related to GPS signal interference coming from somewhere near White Sands. Ops normal!

[archae86]

GPS signal interference coming from somewhere near White Sands. Ops normal!
I live in Albuquerque, and though not a pilot, pay a little attention to GPS affairs. Over the years there have been plenty of localized temporary "unreliable GPS" warnings in this state, in what, based on the affected locations and geometries, appear to me to be tests related to localized GPS jamming.

As since the Clinton administration, it has been stated US policy that we won't use the Selective Availability capability again (and it was announced in 2007 further that future GPS satellite designs would not include even the hardware support for it) localized denial is important to us. I'll hazard a guess that many of the tests are not of the jamming transmission techniques per se, but of the robustness of systems which are supposed to continue working in their presence.

[westhawk]

I'll hazard a guess that many of the tests are not of the jamming transmission techniques per se, but of the robustness of systems which are supposed to continue working in their presence.Perhaps so arch. Or perhaps some other military training or testing activity results in a certain level of signal reception degradation. The exact cause and effect relationship is not stated in any official publicly available document I am aware of.

While flying all over the USA under IFR while using GPS as the primary navigation source, I've noticed that these GPS unreliable NOTAMs appear to be consistently centered in or very near military special use airspace, especially in the mountain west. The interesting thing is that while I've always planned for the NOTAMed GPS unavailability and flown with another NAV source selected while flying across the affected areas, The GPS derived position appeared to remain accurate on all occasions but one. In that one case, (along the CA/NV border on the jet airway between BTY and OAL VORs) the box reacquired sufficient sat signals within a few minutes. Go figure...

[ATC Watcher]

under IFR while using GPS as the primary navigation source

You can do this in the USA ?

[westhawk]

You can do this in the USA ?



Yeah, now we even have this new-fangled thing called RADAR too! And cellular telephones, cars that shift gears automatically.... :ok:

The first time I saw the OpSpec authorizing stand alone GPS RNAV for charter ops was back in about 2000 or so.

[ATC Watcher]

I am impressed !
In my (European registered) aircraft I still have a sticker saying not to be used as Prime means of navigation. EASA said it has to be augmented to do this. But things might have changed.

[Little cloud]

For anyone in the UK most planned GPS jamming by the military is notified here:

Ofcom | GPS jamming exercises (http://stakeholders.ofcom.org.uk/spectrum/gps-jamming-exercises/)

Usually short term and limited in geographical extent. There's also an email notification service available.

[Jet Jockey A4]

Stand alone GPS approaches have been around for a while now, +12 years IIRC.

For FMS computation for short range, long range NAV and RNAV, the GPS system is used at almost at 100 % with hardly anymore blending from outside sources like VOR, DME or IRS.

Only if a failure of the GPS is detected will the other sensors take on a more important role in FMS computations.

[aterpster]

ATC Watcher:

You can do this in the USA ?

Generally, only with an augmented system unless ATC radar is available or its an RNAV LNAV instrument approach procedure. In the latter case a RAIM check must be performed prior to commencing the approach if the avionics are WAAS (GBAS) augmented.

[172driver]

FWIW I recently flew through an area in the SW that the briefer warned me about - unreliable / unavailable GPS signal. Kept a close eye on all three units in the a/c and dialled in the relevant VORs. Nothing happened, no loss of accuracy.

[ATC Watcher]

aterpster : Thanks a lot for the explanation , then it is a similar situation as in Europe.

For those that rely 100% on GPS in mountainous areas,( I know a few still do ) remember that GPS signals can be downgraded in accuracy , or even large areas can be blocked out without prior warning by the US military in case of crisis or war. It did occur during Irak and Afghanistan wars , especially during cruise missiles attacks. I remember New Zealand was the most seriously affected during one of those days.

[aterpster]

ATC Watcher:

RAIM is critically important with a TSO C-129 (non GBAS) unit and even with a GBAS unit (TSO C 145/146) when in a non-GBAS area. I left out the word "not" in my previous post.

[FlightPathOBN]

terpster,

Concur.
If using RNP, the crew is required to check the RAIM prediction of the ARR airport prior to takeoff.
In a few airports with RNP only service, if you do not have adequate coverage per the RAIM prediction, you are not DEP or ARR authorized.

Here is a link to GPS/WAAS RAIM Prediction (http://operationsbasednavigation.com/operations-based-navigation/463-2/)

As GBAS requires GPS, RAIM is critical.

ATC...

As of May 2000, the US will not use selective availability or degrade GPS signals any longer by law. If you look at the RAIM map, you will see areas that are typically affected.

I cannot see where NZ would have had an issue, and I did not see any NOTAMS from AUS or NZ regarding degraded GPS service. You will also note that AUS nor NZ have WAAS capability.

[ATC Watcher]

Thanks for the additional info
you said : I cannot see where NZ would have had an issue, and I did not see any NOTAMS from AUS or NZ regarding degraded GPS service.

From memory this was in August 1998 ( prior 2000 then) when the US sent cruise missiles to Sudan and Afghanistan. They allegedly re-positioned a few satellites to increase coverage and accuracy in the strike areas, depriving large areas of coverage ( NZ was one ) . At least that as the story told then.
I do not think the US did issue a NOTAM prior to the strikes..:E

An interesting debate took place a few years back on how GPS could be use or disused in case of war with the US . if you have interest and time here is a good paper covering it : http://www.rand.org/content/dam/rand/pubs/monograph_reports/MR614/MR614.sec2.pdf

[Flying Binghi]

via ATC Watcher:
...An interesting debate took place a few years back on how GPS could be use or disused in case of war with the US . if you have interest and time here is a good paper covering it : http://www.rand.org/content/dam/rand...MR614.sec2.pdf

ATC Watcher the Rand ? report you link to, whilst interesting, is well and truely out of date reference "(mis-)disused in case of war"

The recent GPS guided drone attacks on Israel have demonstraited just how effective a cheap GPS guided terrorist weapon can be. Now the terrorists know just how effective the GPS guided terror weapons have been we can only expect an escalation of these type of attacks. This does not bode well for civilian availability of GPS.






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[WhatsaLizad?]

Read the Notam for probably 100 of my last transcons in the US. No notice of anything different on my jet and only once did I hear a passing conversation of someone getting a bad signal.

IMHO, GPS is the greatest give away by a country in the history of the world. We should have licensed every receiver to collect royalties above a certtain accuracy level. Low level accuracy should be zero or no cost. The high level accuracy for high value uses should as mining, drilling, bridge and dam building should have paid millions for the savings of billions.

Rant over.:E

[Flying Binghi]

via WhatzaLizard :
...GPS is the greatest give away by a country in the history of the world. We should have licensed every receiver to collect royalties...

If yer read the link via ATC Watcher you would see there has been money made from GPS. The commercial opportunities have ensured the concerns of the military were overruled...

"The United States has a rapidly growing GPS industry whose global sales are expected to..." continues page 16 - http://www.rand.org/content/dam/rand/pubs/monograph_reports/MR614/MR614.sec2.pdf






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[4Greens]

The major safety concern is that there is still only one operating worldwide GPS system. In the jargon a simgle point failure. The sooner we get another system the better.

[Nemrytter]

Not true, GLONASS is also operational on a global scale - we already use it as an alternative to the US GPS.

[riverrock83]

And pretty much every new phone on the market connects to both GLONASS and GPS transparently (as Russia adds an extra tax on all GPS only devices).

[Heathrow Harry]

I think the Chinese have some similar system under development as well - don't trust the Russians OR the Yanks - very very wise

[FlightPathOBN]

Everyone is getting into the game...

GLONASS is the Russian system, Galileo is the EU, BeiDou is Chinese, and IRNSS by India.

GLONASS and GPS are not compatible, so you need a dual mode receiver...

In regards to military vs civilian, all sat systems are dual mode anyways, with the civilian mode set to 10m accuracy and 0.2m/s speed measurement, and the military mode to 10 cm accuracy with unadvertised speed measurement.

[MG23]

This does not bode well for civilian availability of GPS.

GPS is now used widely as a highly accurate time source for electronic systems. Much of the world's infrastructure -- particularly communications -- would fall apart if GPS was to disappear for more than a few days.

[atakacs]

And pretty much every new phone on the market connects to both GLONASS and GPS transparently (as Russia adds an extra tax on all GPS only devices).

Do you have any material to substantiate this ?!

[MarcK]

From cellular-news:
Russia is considering a 25% import tax on any mobile phones that are not capable of connecting to Russia's variant of the GPS navigation system, the glonass satellite network. According to the Russian vice-prime minister, Sergei Ivanov the government has also decided to issue a law, obliging Russian drivers to equip their cars with glonass receivers
Almost all new cell phones support GLONASS along with GPS (See wikipedia)

[riverrock83]

Or look at this list on Wikipedia:
List of Smartphones using GLONASS Navigation - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/List_of_Smartphones_using_GLONASS_Navigation)

Pretty much every phone since middle of last year - so including the iPhone 4S / Samsung S3 / Nokia Lumia _20 (520 / 620 / 820 / 920)

[atakacs]

Interesting - just learned something :ok:

[Flying Binghi]

via MG23:
GPS is now used widely as a highly accurate time source for electronic systems. Much of the world's infrastructure -- particularly communications -- would fall apart if GPS was to disappear for more than a few days.

Yes. A nice big fat juicy target for the terrorists..:hmm:







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[Heathrow Harry]

yeah - terrorists who can simulateously launch a dozen low orbit rockets with a satellite killer on each one - or jam comms across the whole of the world -are going to be ten a penny

[flash8]

Surely glonass would still be available?

[Undertow]

I believe this is another round of LightSquared 4G "GPS Interference Testing" GPS.gov: LightSquared and GPS (http://www.gps.gov/spectrum/lightsquared/) There's a document (which I can't instantly find) from a month or two ago pre-announcing this round of tests.