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Satellite Failure Behind GPS Timing Anomaly (itnews.com.au)

Posted by timothy on from the not-quite-up-to-speed dept.

Bismillah writes: The recent 13-microsecond timing anomaly was caused by a satellite failure triggering a "software issue", the USAF 50th Space Wing has confirmed. Such an error is large enough to cause navigation errors of up to 4 km. Luckily, no issues with GPS guided munition were reported. Reader donaggie03 adds a link to the official explanation from Rick Hamilton, Executive Secretariat of the Civil Global Positioning System Service Interface Committee. From Hamilton's email: Further investigation revealed an issue in the Global Positioning System ground software which only affected the time on legacy L-band signals. This change occurred when the oldest vehicle, SVN 23, was removed from the constellation. While the core navigation systems were working normally, the coordinated universal time timing signal was off by 13 microseconds which exceeded the design specifications. The issue was resolved at 6:10 a.m. MST, however global users may have experienced GPS timing issues for several hours.

62 comments

  1. It were the russians by Anonymous Coward · · Score: 2, Funny

    They hacked the satellite and caused the damage. When they declare war, they will turn off GPS world-wide, and all the US nuclear rockets will be misguided and will land on American soil. We must vote trump so that putin is scared of our army.

    1. Re:It were the russians by bobbied · · Score: 5, Informative

      You are funny, in a deranged sort of way...

      You do realize that the current crop of missile based nuclear weapons are pretty much independent of the GPS system, having been developed BEFORE GPS was built by about a decade.

      GPS launches started back in 1978 and it was a couple of years before we had enough satellites in orbit to be useful. So GPS came on line sometime after 1980.

      The LGM-30 Block 3 is our current land based ICBM and it went into service a decade before in about 1970, but really is a refinement of a 1962 missile. It is guided by an inertial navigation system and is totally independent of outside input while in flight, so it doesn't need to use GPS.

      The current Navy missile is the Trident 3 (USM-96) which uses a guidance system that is both inertial and refines its guidance using astronomical observations in flight. It was developed in the late 70s, but does NOT use GPS during flight for guidance. It too predates a working GPS constellation by at least a decade.

      If the Russians are messing with GPS in hopes of disrupting our nuclear capability, they are a lot more stupid than I ever imagined... The reality is that GPS is not used for positioning information for any kind of nuclear weapon delivery system and it's not used as an exclusive positioning source for any critical military application. This is mainly because the system is already known to be vulnerable to upset and jamming, so alternatives have been considered, alternate equipment obtained, personnel trained in how NOT to depend on GPS.

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    2. Re:It were the russians by Anonymous Coward · · Score: 0

      Since the Earth is actually flat, all of your target predictions will be wrong regardless of GPS. Go ahead and bomb the South Pole, you are more likely to have the bomb go straight up and land on you. - Signed B.o.B

    3. Re:It were the russians by imac.usr · · Score: 1

      Frankly, I would consider a system that worked like that a big improvement.

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    4. Re:It were the russians by Anonymous Coward · · Score: 0

      The LGM-30 Block 3 is our current land based ICBM and it went into service a decade before in about 1970, but really is a refinement of a 1962 missile.

      Silly me, I was worried about commercial airplanes and nuclear reactors being too old. Holy fuck.

    5. Re:It were the russians by Anonymous Coward · · Score: 0

      The nuclear system does not use GPS. It is used by the rest of the military, there are secondary systems with greater accuracy.

    6. Re:It were the russians by SuiteSisterMary · · Score: 1

      It's been a while since I read my 80s techno thrillers, but the idea was a nuke sub (or mobile land-based launchers, in theory, but I don't think they ever bothered with that) would use GPS to get an exact fix on where it was, and input that into the missiles as their start point for inertial navigation. This allowed for 'first-strike' capability, which required silly amounts of precision to hit hardened launch sites on short notice, before enemy C&C could authorize retaliatory strikes, and simultaneously denied the enemy the ability to perform a first-strike on you, as first they'd have to find your hidden SSBNs.

      The GPS system was originally called 'NavStar,' as it was intended as a navigation aide. The missiles themselves were intended to be as autonomous as possible after launch; after all, the GPS satellites were easy to find and destroy, what with them broadcasting their locations.

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    7. Re:It were the russians by Anonymous Coward · · Score: 0

      It is amazing that you could miss such obvious humor.

    8. Re:It were the russians by jeneag · · Score: 1

      They can ask Russians to use their GLONASS system. They already depend on them for rides to ISS.

  2. A missed opportunity... by Anonymous Coward · · Score: 0

    ...to innocently bombard a few DWB hospitals.

  3. SVN? by smittyoneeach · · Score: 0, Offtopic

    Go Git.

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  4. Use for surface navigation by techno-vampire · · Score: 4, Interesting

    Back in '72, when I was in the Navy, one of my friends was a Quartermaster's Mate, involved in (among other things) navigation. He told me that when we went from Pearl Harbor to Subic Bay, in the Phillipenes, that they used 2000 yards for a Nautical Mile, rather than the more accurate 2025, and treated all turns as "point turns" instead of working out the distance needed to make the turn. When we made our landfall and were able to pinpoint our location, we were within two nautical miles of our location by dead reckoning. This will give you an idea of how little an issue this probably was for ships or aircraft, although it might have been a problem for guided munitions with no human oversight.

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    1. Re:Use for surface navigation by TheOzz · · Score: 1

      An aircraft in inclement weather using GPS to find an airport might also have a problem with a 4km error.

    2. Re:Use for surface navigation by sims+2 · · Score: 1

      Especially if it happens to be a 4km error in altitude....Die Hard 2?

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    3. Re:Use for surface navigation by tlhIngan · · Score: 4, Informative

      An aircraft in inclement weather using GPS to find an airport might also have a problem with a 4km error.

      Nope, because if you were using a GPS approach, you'd have checked your destination for sufficient GPS satellite coverage. RAIM (Receiver autonomous integrity monitoring) is something a safety-critical GPS receiver provides. If there are less than 24 satellites in the constellation, it MUST be consulted.

      Basically when you have more satellites than needed to acquire a GPS fix, the additional satellites give you two things - one, an oversolution (Finding GPS location is solving a system of equations - if you have three satellites, you can do an X, Y and Time and get a 2D fix. To get a 3D fix, you need four satellites. If you have more satellites, they can be used to hone your position further.

      The second use is to detect bad satellites - by comparing the results with one satellite out of the calculations at the time, you can detect the bad satellite because your calculations with the satellite in will be vastly different than if it is out. This is what RAIM does, and for GPS approaches, you must have sufficient satellite coverage for RAIM to operate and work. At a minimum, it's +1 more satellite

    4. Re:Use for surface navigation by TheOzz · · Score: 1

      If all satellites are off by 13 milliseconds then you end up with all good signals but a bad position. Not the case here, but just saying.

    5. Re:Use for surface navigation by crbowman · · Score: 1

      I don't want to be off by two miles on any ship that has to navigate subsurface obstacles before it can produce a fix using visible land features.

    6. Re:Use for surface navigation by Anonymous Coward · · Score: 0

      By the 1970s, USN ships were using LORAN-C. The navigator knew where the ship was within 100 meters when you got within 1000 miles of the coast.

    7. Re:Use for surface navigation by techno-vampire · · Score: 1

      The ship managed to navigate all the way across the Pacific Ocean, in deep water with a cumulative position error of only two miles, well over a decade before GPS was available. And, we were still in deep water, well away from any subsurface obstacles when we made landfall and were able to get an exact fix. (On a clear day at sea, the horizon is about 25 nautical miles away. I don't know how far out we were when we were able to identify and use landmarks, but I'd be surprised if we were closer than 20 miles.)

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    8. Re:Use for surface navigation by techno-vampire · · Score: 1

      Yes, they were also using both celestial navigation and LORAN, but they were also using dead reckoning as a backup. The error I mentioned was between the dead reckoning and the position fix.

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    9. Re:Use for surface navigation by Anonymous Coward · · Score: 0

      If all signals are delayed by 13 microseconds there would be no problems, the position would still be valid. The receiver would think his own clock is 13 us off and adjust for it. Typical low cost receives have low quality clocks and have to correct a much much higer clock bias and drift.

    10. Re:Use for surface navigation by AmiMoJo · · Score: 1

      Where GPS can save your bacon is when you get disoriented or make a mistake, and lose track of your position or speed. Dead reckoning is great until something unexpected happens. It's worse for aircraft due to sensors being a bit less robust, and the fact that they can't just stop and ask for assistance.

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    11. Re:Use for surface navigation by Anonymous Coward · · Score: 0

      The ship managed to navigate all the way across the Pacific Ocean, in deep water with a cumulative position error of only two miles, well over a decade before GPS was available. And, we were still in deep water, well away from any subsurface obstacles when we made landfall and were able to get an exact fix. (On a clear day at sea, the horizon is about 25 nautical miles away. I don't know how far out we were when we were able to identify and use landmarks, but I'd be surprised if we were closer than 20 miles.)

      That is very good navigation. But I fear that today's people have become so dependent upon GPS (and other advanced technology) that, without GPS, we'd be hard pressed to navigate from one side of Pearl Harbor to the other without a 20 mile error.

  5. (TFA != Headline) == 1 by Anonymous Coward · · Score: 3, Informative

    In classic Slashdot style, the headline says a hardware failure and TFA says a software bug temporarily mitigated by an operational procedures change.

    Just dreaming, but it might be nice if the poster read TFA so the rest of us don't have to?

    1. Re:(TFA != Headline) == 1 by ColdWetDog · · Score: 3, Funny

      In classic Slashdot style, the headline says a hardware failure and TFA says a software bug temporarily mitigated by an operational procedures change.

      Just dreaming, but it might be nice if the poster read TFA so the rest of us don't have to?

      This is really a test. You just passed it.

      Not sure where it gets you, but this is Slashdot, after all.

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    2. Re:(TFA != Headline) == 1 by MrTester · · Score: 1

      ..or you could read the summary where it says "This change occurred when the oldest vehicle, SVN 23, was removed from the constellation." and generously assume that SVN 23 was removed because of a hardware failure and the removal of a satellite from the constellation triggered the software defect and thus both interpretations are correct.

      But then you would have no excuse to complain, and where is the fun in that?

    3. Re:(TFA != Headline) == 1 by LynnwoodRooster · · Score: 3, Funny

      Not unexpected. /. is overwhelmingly populated by software types. The first thing they ALWAYS blame is the hardware...

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    4. Re:(TFA != Headline) == 1 by Anonymous Coward · · Score: 0

      Or you could assume some unfriendly operatives were known to be using GPS for their operations during that particular time period, and the signal was purposely degraded to interfere with them, then a story was made up to explain the event. I like that story better.

    5. Re:(TFA != Headline) == 1 by Whip · · Score: 1

      You *could* assume that SVN23 was removed because of a hardware failure. But since SVN23 was scheduled to be decommissioned right about now (or, at least, before the launch of a new satellite next month), I'm not sure that's the assumption *I* would make.

      Really, if it was a satellite failure, I'd expect the official statement to say "there was a satellite failure" rather than "the configs got screwed up when we decommissioned something". There's nothing anywhere that says there was any kind of failure (other than in process), so I'm not sure how "there was a failure" is any kind of valid interpretation of the available information.

    6. Re:(TFA != Headline) == 1 by Anonymous Coward · · Score: 0

      Really, if it was a satellite failure, I'd expect the official statement to say "there was a satellite failure" rather than "the configs got screwed up when we decommissioned something".

      It was unusable before it was decommissioned.

      UNUSABLE START TIME ZULU: 1536
      DECOMMISSIONING TIME ZULU: 2200

      Sounds like a failure to me.

    7. Re: (TFA != Headline) == 1 by Anonymous Coward · · Score: 0

      It was unusable when the error occurred. Svn23 was retired to make room for a newer satellite. 23 was the oldest satellite in the constellation and was almost 2 decades beyond its design life and was scheduled for decommission this month.

    8. Re:(TFA != Headline) == 1 by Whip · · Score: 1

      "Unusable" is a standard field in the DECOM template, see https://celestrak.com/GPS/NANU...

      And doing a little browsing, I see that SVN32 had an earlier notice: http://www.navcen.uscg.gov/?Do...

      The earlier notice was of type FCSTUUFN -- Forecast Unusuable Until Further Notice: Scheduled outage of indefinite duration. And that notice says that the start time of that unusability period was 025/1500. And the start time of the unusability period in the DECOM notice you linked was 36 minutes after that: 025/1536. So, they said that it was going to be unusable around 15:00 and it was actually unusable at 15:36. And the notice itself was posted on Jan 20.

      So I'm going to update my response from "I don't read that as a failure" to "definitely not a failure", barring an explicit statement otherwise by someone actually running the GPS constellation.

  6. First Post ! by psergiu · · Score: 4, Funny

    First Post !
    I'm able to post that fast 'cause i'm using a GPS-synced clock.

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  7. Another dupe? by Anonymous Coward · · Score: 0

    From Tuesday.

    1. Re:Another dupe? by NotInHere · · Score: 1

      This story is rather a followup than a dupe.

  8. Lack of replacements? by AHuxley · · Score: 1

    The ability to fund and replace the network of legacy satellites well past their design life seems to be the issue.
    Even to bolster the backup capability thats ready in orbit.
    The life capability is been stretched out for many more years and the conservative number of backups is now starting to show for the fleet.
    The "reserve role" is even been packed with older systems rather than replacement with new..

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    1. Re:Lack of replacements? by Zak3056 · · Score: 1

      [citation needed]

      Per wikipedia, 11 new satellites have been launched in the last five years, 18 in the last ten. This argues against your "we just afford to can't replace them" claim.

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    2. Re:Lack of replacements? by AHuxley · · Score: 1

      Re 'we just afford to can't replace them"
      "GPS upgrade set to launch on replacement mission" (February 20, 2014)
      http://www.usatoday.com/story/...
      ""We have a lot of satellites that are well past their design life,""
      " "We're trying to prevent any sort of outage and (have) some backup capability on orbit.""
      ""We've really gotten remarkable performance out of them, but they are aging, and there are some components that simply wear out," s"
      "US Air Force Launches New GPS Satellite" (February 21, 2014)
      http://www.space.com/24767-gps...
      "In this particular case, the satellite we are replacing is over 16 years old and its design life was 7.5 years."

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  9. celnav skills by mspring · · Score: 1

    Time to service your sextant and brush up on your celestial navigation skills.

    1. Re:celnav skills by ColdWetDog · · Score: 2

      That just shivers me timbers.

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    2. Re:celnav skills by bobbied · · Score: 1

      I depend on dead reckoning wherever I go navigating... Hand me that compass and a stop watch! That's all we needed when I was young and bare foot in the snow, going uphill, both ways.

      Sextants are for sissies and unless you know what time it is, generally useless during the day.

      Why is there moss on the other side of that tree?

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    3. Re:celnav skills by LynnwoodRooster · · Score: 1

      Why is there moss on the other side of that tree?

      Because you're in the Pacific Northwest and EVERYTHING is coated on all sides by moss.

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  10. Drones fly away? by NewtonsLaw · · Score: 1

    I wonder how many DJI Phantoms (the Phantom Menace) and other drones decided to fly 4Km away at that time?

    1. Re:Drones fly away? by Anonymous Coward · · Score: 1

      0, as navigation wasn't affected at all.
      Protip: If your navigation depends on a GMT-GPS time offset field, you're doing it wrong.

    2. Re:Drones fly away? by sims+2 · · Score: 1

      Would that be covered by warranty? Afaik the standard failure mode RTC (aka return to china where the drone takes off at top speed in the direction of china) is not covered.

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  11. should of hacked Galaxy 15 4080 H by Joe_Dragon · · Score: 1

    and made it free.

  12. GPS WTF?! by Anonymous Coward · · Score: 1

    We have systems with GPS-disciplined oscillators in them, and certain older models of GPS receivers went berserk during this event. This caused a lot of WTF?! activity until we concluded there was nothing wrong with our software. It really was GPS that was acting up.

    1. Re:GPS WTF?! by Anonymous Coward · · Score: 1

      I work in cellular and most base stations use GPS to sync, but due to past issues where something similar to this happened, our stuff is designed to use a majority vote for timing, so if one or two satellites have this happen, it doesn't effect us. You should consider modifying your hardware to do the same.

    2. Re:GPS WTF?! by Anonymous Coward · · Score: 0

      The receivers that acted up are old. Old enough that they only report week numbers from 0 to 1023. We're swapping them out for newer ones that behaved properly, but the bean counters won't let us do it as fast as we would like.

    3. Re:GPS WTF?! by Whip · · Score: 1

      This was not a problem where "one or two satellites" had something bad happen. Even well-designed GPSDOs had a problem with this one, since large chunks of the constellation were broadcasting a bad A0 parameter.

      The best-designed, of course, went "uh, something really weird just happened with time, I'm gonna stop tracking GPS and throw an alarm," but that had nothing to do with getting disagreeing data from satellites and everything to do with good clocks realizing that a 13s jump in time meant something somewhere was wrong in ways that it's impossible to recover cleanly from.

  13. BoxLagu Mp3 by Anonymous Coward · · Score: 0

    Download Lagu Terbaru http://boxlagu.xyz

  14. BoxLagu Mp3 by naraabdel · · Score: 0

    Download Lagu Terbaru http://boxlagu.xyz

  15. Fail Gracefully by Anonymous Coward · · Score: 0

    Not.

    Fail at Graceful Fail.

  16. Replacement by Anonymous Coward · · Score: 0

    This change occurred when the oldest vehicle, SVN 23, was removed from the constellation.

    This just in: they've replaced it with GIT C4A246E. All has returned to normal.

  17. Wouldn't RAIM work around this issue? by auzy · · Score: 1

    Wouldn't GPS RAIM be able to work around this issue anyway (leaving only consumer GPS devices with problems?)

    1. Re:Wouldn't RAIM work around this issue? by Whip · · Score: 1

      Not in this case, because the particular error was a configuration error that multiple satellites were broadcasting (and they agreed with each other). RAIM works by noticing that a satellite differs a lot from what is expected based on what the rest of the constellation is doing... when a chunk of the constellation is all saying the same (wrong) thing, RAIM can't really do anything about it.

  18. SVN? Really? by LocutusOfBorg1 · · Score: 1

    "when the oldest vehicle, SVN 23" This might explain everything. You will always loose time, this is why GIT is faster! (sarcasm)

  19. Russian plane in Turkey by GPS, but GPS was failed by Anonymous Coward · · Score: 0

    So how does this 4km margin of error play in the Russian plane downing by Turkey? GPS showed the plane over Turkey but GLONASS showed it quite a bit away from it? :)

  20. lucky.. by Anonymous Coward · · Score: 0

    That no one survived to file a report..

  21. no nav errors, just time by Anonymous Coward · · Score: 0

    All this blather about 4km error is someone dividing 13.7 microseconds by the speed of light.

    The error was not in the GPS time, or in the nav solution, so your JDAM bomb or your ICBM or your geofenced garage door opener all worked just fine.

    The error was in the conversion from GPS to UTC. GPS time has no leap seconds. UTC does. The GPS satellites broadcast a message that says "the current difference between GPS and UTC is X" (It's actually coefficients in an equation, but same function). That data was in error.

    RAIM wouldn't show a problem because the nav solution was still perfect.

    Who gets shafted by this? People using UTC time that care about microseconds... like high frequency traders using GPS receivers to time stamp their transactions.

    People who use time in a serious way (e.g. for navigating deep space probes) don't use UTC anyway: they use TAI or GPS time. UTC is just a way to get noon to happen when the sun is highest in the sky.

    1. Re: no nav errors, just time by Anonymous Coward · · Score: 0

      This affected anyone using PPS for frequency or timing. This includes standard frequency sources such as GPS disciplined oscillators, and timing systems like NTP.