# Ever experience unexplained GPS failures like this?



## phdad (Sep 5, 2019)

The call came in by radio one evening last September, at around 9 p.m. On the line was the master of a tanker, approaching the end of a monthlong journey from the Port of South Louisiana and carrying more than 5,000 metric tons of ethanol. The message was urgent: The ship’s GPS signal had suddenly disappeared—leaving the crew to navigate Cyprus’s shoreline in the dark. 
On the other end of the line was the pilots’ office at the Vasiliko oil terminal, whose staff oversees shipping traffic at Vasiliko’s harbor on Cyprus’s arid, palm-fringed southern coast. Stelios Christoforou, the pilot on duty, recognized the gravity of the situation right away. In daylight, an experienced ship captain can maneuver using paper maps, markers, and the coastline as guides. But at night, GPS becomes a critical tool in unfamiliar waters—especially near Cyprus, where NATO and Russian warships roam. And any accident could spill the tanker’s cargo across miles of coastline.


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## David Wilcockson (Jul 10, 2005)

So what happened?


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## jmcg (Apr 20, 2008)

He's gone!

BW

J


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## phdad (Sep 5, 2019)

I was not aboard, however, as I understand it the Captain performed a large circle course which allowed him go to port at first light.


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## Mad Landsman (Dec 1, 2005)

Was it fault on the ship's GPS?
Did it self restore?


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## James_C (Feb 17, 2005)

Whether it's daylight or night should make no difference to dealing with a GPS failure. 
He still has his charts and can use either visual bearings or radar ranges/bearing to determine his position.


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## callpor (Jan 31, 2007)

Totally agree with James_C, if he couldn't navigate without GPS he/she should not be Master or Navigator of any vessel.

I experienced a similar GPS interuption 75 nm south of Cyprus on passage from Haifa to Greece in 2018 which lasted about 3.5 hours. This was whilst carrying out an independent Navigational Assessment on a Greek bulker which had a full Filippino crew. The navigators responded appropriately using their established GPS failure procedures, reverting to DR positions on the duel ECDIS which corresponded well to the actual position when the GPS signal restored. The small scale eastern Mediterranean chart in their "get me home folder" was produced on the chart table, but only used for situational awareness. At the same time the vessel experienced continuous disturbances on the radar with multiple high speed echoes tracking across the screens. Nothing obvious was heard or seen, but there was a lot of USN and Russian naval activity in the area which could be heard on VHF. The loss of GPS signals in this area was reported to the appropriate authorities (British Admiralty HO). Subsequently we learnt that these events were not uncommon in this area where GPS jamming is regularly experienced probably from both government and military sources!
The message is very clear, do not be totally reliant on GPS for postions, but continue terrestial and celestial navigational practices, whereever you are.
Cheers. Chris


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## lakercapt (Jul 19, 2005)

Panic when the GPS is not functioning!!
What a change in today's navigation to when we used the skills we were taught.
I think it has come to the stage we must rethink the qualifications to become a master( or person in charge of a vessel)


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## sparks69 (Dec 18, 2005)

Reminds me of my son whose car apparently has automatic braking when he gets too close to a vehicle in front.
He took his wife's "primitive" car to work one morning and ran into the back of another vehicle. 
Progress is not always a "good" thing ?


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## phdad (Sep 5, 2019)

Mad Landsman said:


> Was it fault on the ship's GPS?
> Did it self restore?


Best guess based on information provided to me, it seems that GPS signals were jammed.


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## lakercapt (Jul 19, 2005)

sparks69 said:


> Reminds me of my son whose car apparently has automatic braking when he gets too close to a vehicle in front.
> He took his wife's "primitive" car to work one morning and ran into the back of another vehicle.
> Progress is not always a "good" thing ?


My Nissan Murano has this feature and it is a thing you get used to and if you forget to turn it on can cause bum puckering experiences.


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## Mad Landsman (Dec 1, 2005)

phdad said:


> Best guess based on information provided to me, it seems that GPS signals were jammed.


Yes I'm getting the drift of that now from other's replies. 
Considering that GPS is basically a military system which the rest of us are allowed to use, it would make sense that military exercises would involve some form of interruption to the transmission. On the basis that it would happen in the scenario that the exercise represents.


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## Troppo (Feb 18, 2010)

James_C said:


> Whether it's daylight or night should make no difference to dealing with a GPS failure.
> He still has his charts and can use either visual bearings or radar ranges/bearing to determine his position.


Exactly....


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## sparks69 (Dec 18, 2005)

One of course assumes that there are adequate charts (or the USB with all the charts on) on the ship and the people can actually interpret them. 
I'm not being sarcastic either.
Anything military will be an obvious target of an enemy ?
Sat Nav is nice (when I left in the mid 80's - amazing) but like the sun and the stars is not 100% reliable.
Interesting read in the UK Sunday paper this morning with an article on autonomous unmanned ships run by AI.
No more Hello Sailor more Bye Bye Sailor ?


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## Jack A Pitcher (Aug 27, 2020)

A full interruption may be unusual but in fact it is normal - and should be expected. The GPS system including all 24 satellites (plus a couple of spare ones) deployed is the sole property of US Department of Defense and they clearly state that in allowing free international use of it they reserve the right to disrupt it without notice and/or deliberately impair its accuracy and reliability in the version accessible to everyone except US Government entities. This is primarily a matter of their national defense, but also occurs during exercises or maintenance or during exchange of active satellites or orbital correction.


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## Varley (Oct 1, 2006)

I think the Clinton administration ordered 'Selective availability' (the deliberately made less accurate facility to which non-US Navy users were allowed access) to be discontinued in 2000.

Not even NATO partnership guaranteed access to the nominal accuracy feature.

There were ways to improve the accuracy of the Sub-nominal (Selective availability) feature. One of the equations that receiver must solve is time so that if the receiver can be fed a direct and accurate 'time signal' such as with a Caesium beam standard clock it has one very accurate parameter without having to calculate it from the satellite signals especially (?) as it is wobulation of the transmitted time that is what degrades the 'Selective availability' access. The conventional trading vessel should have been quite happy with the pre-2000 public service..


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## Victor J. Croasdale (Nov 28, 2016)

I'm a retired engineer. Until a few yeas ago I worked for an engineering and surveying company. On the roof of our building there was a system base station, its position was very well defined by traditional surveying. When a surveyor out in the field used his GPS it sent a signal to the base station. Back in the office when the data was imported to Autocad, the system calculated an offset to be applied to the field readings. They had an accuracy of better than a foot.


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## harry t. (Oct 25, 2008)

someone's taking the piss with this post. Do they not understand gps is only an aid to navigation.


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## Varley (Oct 1, 2006)

harry t. said:


> someone's taking the piss with this post. Do they not understand gps is only an aid to navigation.


I agree with respect to conventional cargo vessels but it is many other things to many other people (it is now used for DP, where high repeatability equating in this case to high accuracy). It is used to provide 'time' and, of course, one would not want one's cruise missile going through the wrong window. What surprised me was the number of navigators (principally) on this thread that were ditching the hambone and chronometer and relying only on GPS.

(I had cause to take the Astronomer Royal to task when I heard him on R4 declariing ;'we now rely on GPS'. Obviously a good egg, he interrupted his Christmas break to give me reply - agreeing that we should not give up the hambone).


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## harry t. (Oct 25, 2008)

Know matter how you put it, the original post related to basic navigation and the good practice of seamen, not the undoubted improvements and accuracy of gps over spherical trigonometry, - it’s still just one of many aids to navigation.

Until that’s understood, any examiner would give you another 6 months sea time – to think it over.


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## Troppo (Feb 18, 2010)

harry t. said:


> Know matter how you put it, the original post related to basic navigation and the good practice of seamen, not the undoubted improvements and accuracy of gps over spherical trigonometry, - it’s still just one of many aids to navigation.
> 
> Until that’s understood, any examiner would give you another 6 months sea time – to think it over.


Ha! Indeed...


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## Varley (Oct 1, 2006)

In think your Ha! would raise that to 12 months.

But. What tests of competence concentrates on the safe navigation of a vessel carrying only that equipment demanded by SOLAS? Much noise is being made of the learning around ECDIS and its equipment specific training - seemingly not as effective as the world might like. But by SOLAS you have no sextant or chronometer. Perhaps it is difficult to blame ECDIS on the current problems (ships being exactly where they planned to be except that place being somewhere where they should not be) as that would have to be measured against how they would have erred given a proper chart, possibly onboard, possibly corrected, unlikely to have been on the chart table and even more unlikely to have a position plotted).

I wonder if it will take another of Sir Cloudesley's line to founder for the common good (if not that of Her Majesty's Navy) to return to an environment of professional seafaring (even if those taking it up would need to be teetotal eunuchs to enjoy the life now on offer).


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## harry t. (Oct 25, 2008)

Professional seamen (navigators) would be suspicious and dispense with gobbledegook, sticking to ‘apples and oranges’, much simpler and easier to understand than talking about terrestrial spheroid’s etc. Once you understand the very old but basic principles of navigation everything that came later is just an aid to a subject that never was an exact science, as Sir Cloudesley and most of his fleet found to their misfortune, without the aid of a chronometer – it can be hit or miss, particularly if relying on DR positions. Anyhow, stick to the first principles irrespective of any aids to navigation and you’ll keep her off the rocks – and out of the courts.

Circa.1970’s - I forget the parameters when DP was used in cir***stances such as working close to rigs or with divers down, particularly when the weather turned inclement. No doubt it did a better job than I could manually, allowing me to relax with the ‘feet up’ and enjoy a cuppa and a wee puff on a ciggy. Earlier I remember the owners keeping in touch via satellite, the bridge ticker tape spewing out instructions and like most of my generation, thought it magic, invariably replying only, with one finger - ‘how now brown cow’ – as we didn’t appreciate the intrusions from owners and some charterers. But, as you say, things have changed. – indeed, whoever started this post, is clearly taking the piss.


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## Varley (Oct 1, 2006)

Well, I think we are on the same wavelength Harry T but that might be taken as suggesting Sir Cloudesely would have been a pussy had he had and used a chronometer.


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## lagerstedt (Oct 16, 2005)

phdad said:


> The call came in by radio one evening last September, at around 9 p.m. On the line was the master of a tanker, approaching the end of a monthlong journey from the Port of South Louisiana and carrying more than 5,000 metric tons of ethanol. The message was urgent: The ship’s GPS signal had suddenly disappeared—leaving the crew to navigate Cyprus’s shoreline in the dark.
> On the other end of the line was the pilots’ office at the Vasiliko oil terminal, whose staff oversees shipping traffic at Vasiliko’s harbor on Cyprus’s arid, palm-fringed southern coast. Stelios Christoforou, the pilot on duty, recognized the gravity of the situation right away. In daylight, an experienced ship captain can maneuver using paper maps, markers, and the coastline as guides. But at night, GPS becomes a critical tool in unfamiliar waters—especially near Cyprus, where NATO and Russian warships roam. And any accident could spill the tanker’s cargo across miles of coastline.


What happened in the days when there was no GPS. The more we turn to digital modes, the more this type of situation is going to happen. Should we train sea going staff in the old ways again as well as all the modern.
Blair Lagerstedt


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## harry t. (Oct 25, 2008)

A good morning to yourself Varley, it’s well recorded there wasn’t an accurate timepiece available to navigators in Cloudesely’s days hence the navigator’s reliance on DR’s (Dead Reckoning - guesswork) to calculate longitude. Resulting in far too many tragedy’s at sea. That was the worst with the loss of so many fine men and treasure from their battles. That incident galvanised parliament to put up the wherewithal to resolve the problem, hence the ships chronometer, as we know it today.


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## Troppo (Feb 18, 2010)

lagerstedt said:


> Should we train sea going staff in the old ways again as well as all the modern.
> Blair Lagerstedt


They are....


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## Varley (Oct 1, 2006)

Harry T. Too much praise for Harrison (by implcation anyway). The docudrama made too much of the timepiece and not enough of Nevil Maskelyne (except to make him out to be the buffoon he was not). The chronometer was too much for many pockets and his (with his mentor and predecessor in post but one, Halley) lunar distance method held sway until the chronometer was less expensive.

(In the days when we were legitimately replacing those of the clockworkery kind with quartz (lcheap compared with the overhaul of precision engineering) I could have had one for nothing. Now it is GBP 1100 for the mediocrist model).

Troppo. Unfortunately the practice is something that cannot be maintained. Is anyone doing sights for a noon position daily? I suggest, without that, the fluency goes out of the window. We cannot expect the same dedication as those celestially navigating for the hydrographers (I have a lunching companion who was and he astonished me when saying they had their own personal 'errors') but without the fluency that practice instills it must remain a fall back. I think it would take some ionospheric catastrophy, forcing the majority back to Lagerstedt's 'old ways', before the general performance again became commercial/safe on the macro scale.


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## harry t. (Oct 25, 2008)

*Earlier posts – First Sextant
harry t.*
Registered
Joined Oct 25, 2008
1,103 Posts
#18 • Apr 4, 2019

In 1959, for £10 at Smithfield market in Belfast I bought, a Heath & Co. London SE9.- 1911, with an endless tangent screw and a “new automatic clamp”. It cost another £2.12s.06p to post it to the National Physical Laboratory in London to have it tested and checked for accuracy. A fat lot of good on my first trip 2nd mate, a rhumb line to the Azores thence a Great Circle to the Chesapeake on an old ‘empire’ ship on a ballast passage from Cork to Baltimore. DR positions only for the first 24 days, when we finally got a ‘blink’ of the sun, the lady was 200 miles to the south and 300 miles astern. The old man wasn’t too impressed.

* harry t.*
Registered
Joined Oct 25, 2008
1,103 Posts
#23 • Apr 5, 2019 (Edited)

I flew into Manila looking to engage an experienced tug crew. Jesus, a Filipino tug Captain, in trouble with the authorities for breaking an employment contract whilst operating his tug in the Mekong River. Vietnam and Cambodia where dangerous places in the early seventies. His nerve cracked when the chicken wire he had rigged to catch and protect his wheelhouse from rockets fired by Vietcong wasn’t up to the job.

I talked him into bringing his whole crew of experienced tugboat men to join me. The main part of the two year deal we signed was that I teach him celestial navigation. As not one of them spoke a word of English a large part of the bridge wing deck was painted with blackboard paint and many balls of chalk used to communicate by numbers and stick men. Neither he nor his first mate had ever set eyes on Admiralty tables but with perseverance and patience I had them crossing a longitude by chronometer with a meridian altitude in six weeks. A running fix in months and star sights by the end of the year. They found using the instrument of double reflection on a bouncy wee tug the most difficult.

You’re wrong there old son. If you take the trouble to learn the 1st principals of a subject they will stick with you for all time, particularly if your wellbeing or life could depend on it - the good practice of seamen - you seem to have long forgotten.

Yes, GPS made us lazy but it was a wise man who “kept his hand in” and opened the sextant box now and again, as it was deemed good practice even though it might take a few minutes of revision.

My earlier remarks were left open ended as you clearly insist on having the last word.

I made my point, subject closed.


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## Varley (Oct 1, 2006)

I am so sorry I had no idea we were in some humourless competition..


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## J. Davies (Dec 29, 2010)

GPS, the US Navstar system, is all rather old hat anyway. We should refer to it as GNSS now, which includes the Russian GLONASS and Chinese Beidou satellite constellations. Europe has had one on the drawing board for years, but is not quite there yet, therein lies a tale no doubt.

All modern GNSS receivers can process Russian, American and Chinese systems, so if one fails completely you still have two more which the receiver will use automatically. On DP ships of course, it will flag a warning, which is often weighed up as being non-critical because of the other available position reference systems, (and of course the GNSS still has redundancy).

I can remember when the old Transit navigation system came out. Huge great box on the bridge generating lots of heat giving a fix every 4 hours or so. The 3rd mate would rush up to the monkey island with his sextant and return triumphant declaring the satellite was out by 50 NM.


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## pippin (May 13, 2008)

Being a mere R/O all the navigational mumbo-jumbo passed way over my head.
Having also done A Level chemistry, what I picked up in the original post was the mention of ethanol pollution.
Ethanol is alcohol! 
Spill that and it would evaporate in no time at all.
That is if it didn't burst into flames first - poof!

By the way, just in case the satellites fall out of the sky, I can still do 25wpm Morse Code.


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