GPS anxiety

[[194224]]

Anyone with 5 bucks worth of electronics has the capability to block GPS, it’s a very weak signal.
The question is why they’d bother. Neither side needs GPS to be functional for anything bigger than a drone so they’d only really achieve annoying civilians.

I'd agree with that. Spoofing though does require somewhat more that a cheaply made broad spectrum noise generator to disrupt matters. Furthermore it is more insidious as the receiver still appears to be giving valid position and timing information. The article cited seems to conflate the two but they are different "The missing or fake GPS signals — known as GPS jamming". To me "fake" signals arise from spoofing not jamming or blocking. I may be wrong.

 

[Refueler]

Pal of mine during Soviet time was a 'Radio Operator' ... about 1km from where I live is an old soviet building - he worked in there.

His job was to transmit 'white noise' to disrupt BBC and Voice of America radio broadcasts. As he said - most of the time they actually listened to the stations and only switched on the 'white noise' when the KGB guy was around ...

 

[lustyd]

I'd agree with that. Spoofing though does require somewhat more that a cheaply made broad spectrum noise generator to disrupt matters. Furthermore it is more insidious as the receiver still appears to be giving valid position and timing information. The article cited seems to conflate the two but they are different "The missing or fake GPS signals — known as GPS jamming". To me "fake" signals arise from spoofing not jamming or blocking. I may be wrong.

All of the modern systems support encryption. It’s not enabled for civilian use but it’s there. If spoofing became an issue I’m sure it would be enabled in a heartbeat.
I believe some of the systems allow a paid licence for features too, certainly the EU one was going to offer higher precision for a cost but not sure it ever happened since we already have dual channel available.

 

[zoidberg]

It is reported in news that wide-area GPS jamming/spoofing is being done over large areas of Israel, with speculation that an Iranian/Hezbollah missile attack is imminent.
All trained missile defence operators are 'called up' and all military leave cancelled.

That development may not have any impact on our activities, but it will have some significance for RAF and RN personnel operating in the region.

 

[requiem]

Surely somebody has shown considerable delight in "annoying" civillians so far. I assume & I stress, asssume, that ferries & the like use GPS. Should one get into difficulties, due to a sudden unexpected disruption in the signal, before the navigator could correct the situation, that would cause mayhem. Likewise, a tanker sinking causing an evironmental disaster would not worry Vlad the Invader one jot.

Most likely to be a problem for small craft. Tankers (and really anyone on electronics) should be cross-checking their plotted position by eye or by radar at regular intervals.

 

[garen]

I was taught to "layer" it - in case one system breaks, you must have a contingency plan (even if you're just coastal cruising). The setup that I'm aiming for is pretty simple/low-cost but follows this logic:
* iPad (in waterproof case) with Navionics & PredictWind
* My iPhone can get GPS coordinates when there is no 4G internet
* Garmin GPSmap 78sc
* My backup radio has a GPS function too
* Paper chart of the area (an absolute must have!!!)
* A marine compass in cockpit (plus at least another map compass like Silva), rulers and drafting compass (that masonic thingie), protractor, etc.
* I know how to navigate by stars and I'm looking forward to learning how to use a sextant and a watch.

It's not anxiety. It's an integral part of sailing.

 

[st599]

I was taught to "layer" it - in case one system breaks, you must have a contingency plan (even if you're just coastal cruising). The setup that I'm aiming for is pretty simple/low-cost but follows this logic:
* iPad (in waterproof case) with Navionics & PredictWind
* My iPhone can get GPS coordinates when there is no 4G internet
* Garmin GPSmap 78sc
* My backup radio has a GPS function too
* Paper chart of the area (an absolute must have!!!)
* A marine compass in cockpit (plus at least another map compass like Silva), rulers and drafting compass (that masonic thingie), protractor, etc.
* I know how to navigate by stars and I'm looking forward to learning how to use a sextant and a watch.

It's not anxiety. It's an integral part of sailing.

When GPS is being affected, it doesn't disappear, you can just appear to be in a slightly different location. Your GPS doesn't give you any indication there's a problem.

 

[requiem]

When GPS is being affected, it doesn't disappear, you can just appear to be in a slightly different location. Your GPS doesn't give you any indication there's a problem.

Depends on the sort of problem. I wish I had captured a screenshot of the one time my app showed an HPE estimate of ~1600 meters.

The simplest is to simply check a radar overlay against the chart. If you can't do an overlay you can find something distinctive on radar and plot a radar fix on the phone. I'm pretty sure you can do that even on Navionics. If no radar then you can simply plot LOPs on your phone/tablet/whichever (this does require having a proper nav app though).

 

[Refueler]

I was taught to "layer" it - in case one system breaks, you must have a contingency plan (even if you're just coastal cruising). The setup that I'm aiming for is pretty simple/low-cost but follows this logic:
* iPad (in waterproof case) with Navionics & PredictWind
* My iPhone can get GPS coordinates when there is no 4G internet
* Garmin GPSmap 78sc
* My backup radio has a GPS function too
* Paper chart of the area (an absolute must have!!!)
* A marine compass in cockpit (plus at least another map compass like Silva), rulers and drafting compass (that masonic thingie), protractor, etc.
* I know how to navigate by stars and I'm looking forward to learning how to use a sextant and a watch.

It's not anxiety. It's an integral part of sailing.

Fine except for one thing ... if GPS is being affected by 'someone' ..... your list is based on receiving GPS data ... regardless of what is receiving it.

 

[Gadget257]

GPS Spoofing/Jamming is not difficult given the 50w transmission power of the average GPS satellite. As was reported a few year back the Iranians even fooled a US drone to land on the wrong airfield. It is something we (sailors) should be aware of and prepare for - as we do for most eventualities at sea. However, the weakness of almost all electronic plotters and software (with the notable exception of AngelNav) is that you cannot or it is insanely difficult to plot using traditional means. Until the big plotter manufactures enable hybrid plotting (traditional and electronic) paper charts are a must.

I do have an app on my phone where I can take a sextant sight and check for spoofing of the GPS - but perhaps I am taking it a little far.

 

[garen]

Fine except for one thing ... if GPS is being affected by 'someone' ..... your list is based on receiving GPS data ... regardless of what is receiving it.

Fine, except for, as I stated at the end of the list you still have paper charts, and knowledge how to navigate by compass, stars, and get quite a precise location using a sextant.

 

[lustyd]

Until the big plotter manufactures enable hybrid plotting (traditional and electronic) paper charts are a must.

I don't see why they would. In the grand scheme of things none of their customers are asking for this as a feature, and it's to protect against a problem that has effectively never happened.
Sure, a couple of people out of millions might have asked. Yes, there are one or two reported cases out of millions of successful journeys. Does that justify the development costs? Not really.
From a manufacturer perspective they are far better served integrating with electrical systems like Victron - that does sell more units and people are demanding it. Integration with entertainment the same, and safety systems like cameras, infrared and AI all have demand and shift units.
If they were to address this problem at all, I imagine it would be to use AI to detect problem signals, but even that would be a waste of resources from a business perspective.

I disagree that paper charts are a must in most of the world cruising grounds. They are nice to have, but a must is stretching things. In the vast majority of places there is buoyage, and even without buoyage there's usually enough visual information to dead reckon your way to somewhere safe. From a safety perspective, you don't need precision, you just need to avoid danger and that doesn't require plotting anything on the chart. We all learn this with pilotage notes - keep the lighthouse to port and you'll be safe or keep these things in transit and you're safe, keep the depth over 20m until you can see into the harbour clearly etc.

 

[st599]

I don't see why they would. In the grand scheme of things none of their customers are asking for this as a feature, and it's to protect against a problem that has effectively never happened.
Sure, a couple of people out of millions might have asked. Yes, there are one or two reported cases out of millions of successful journeys. Does that justify the development costs? Not really.
From a manufacturer perspective they are far better served integrating with electrical systems like Victron - that does sell more units and people are demanding it. Integration with entertainment the same, and safety systems like cameras, infrared and AI all have demand and shift units.
If they were to address this problem at all, I imagine it would be to use AI to detect problem signals, but even that would be a waste of resources from a business perspective.

I disagree that paper charts are a must in most of the world cruising grounds. They are nice to have, but a must is stretching things. In the vast majority of places there is buoyage, and even without buoyage there's usually enough visual information to dead reckon your way to somewhere safe. From a safety perspective, you don't need precision, you just need to avoid danger and that doesn't require plotting anything on the chart. We all learn this with pilotage notes - keep the lighthouse to port and you'll be safe or keep these things in transit and you're safe, keep the depth over 20m until you can see into the harbour clearly etc.

As has been discussed, MCA, RIN and RYA are all looking in to this very problem as at present no-coded pleasure vessel can operate using GPS alone, without fitting a full ECDIS system (which is impossible on a yacht). This is a huge problem for the leisure sector when UKHO are discussing ending paper chart production.

 

[Daydream believer]

I disagree that paper charts are a must in most of the world cruising grounds. They are nice to have, but a must is stretching things. In the vast majority of places there is buoyage, and even without buoyage there's usually enough visual information to dead reckon your way to somewhere safe. From a safety perspective, you don't need precision, you just need to avoid danger and that doesn't require plotting anything on the chart. We all learn this with pilotage notes - keep the lighthouse to port and you'll be safe or keep these things in transit and you're safe, keep the depth over 20m until you can see into the harbour clearly etc.

I have been sailing the Thames estuary since 1968 & although I have loads of quirky bits to tell me where to head there is absolutely no way I would consider sailing that area without a chart.( albeit a bit out of date) I am sure that there other areas around the UK & across the channel that some would agree.
True there is buoyage, but try & see a buoy at over .5 of a mile in F6 when it is p..ing with rain, & your glasses are misted up, is not exactly that easy. The echo sounder is great when used with a compass but if you do not know which sandbank it is that you are crossing then you could be in trouble
.
With modern plotters so widely available, I doubt that many actually prepare pilotage notes, other than possibly a list of waypoints & tide times. These being plotted on to the unit . From there on they probably do not bother with writing down lighthouse details, buoyage notes & the like. So if the GPS goes down or the electronic chart info fails, without warning,they would not have the pilotage notes that they studied when they did their day skipper.
.

 

[Refueler]

As has been discussed, MCA, RIN and RYA are all looking in to this very problem as at present no-coded pleasure vessel can operate using GPS alone, without fitting a full ECDIS system (which is impossible on a yacht). This is a huge problem for the leisure sector when UKHO are discussing ending paper chart production.

mmmmm just reading your post and sitting here trying to figure out your point ...

ECDIS relies on GPS ... Full Stop.

It usually integrates Radar / ARPA ... AIS .... :

The ECDIS utilises the feature of the Global Positioning System (GPS) to successfully pinpoint the navigational points. It also has to be noted that the ECDIS adheres to the stipulations set by the International Maritime Organisation, and thus it adds to the trustworthiness of the electronic chart system.

ECDIS is basically a navigational information system, interfaced with other navigational equipment such as the GPS, Gyro, RADAR, ARPA, Echo Sounder etc.

Where will the position info come from for the ECDIS system ? Omega (discontinued), Decca (discontinued), Loran (trying to remember where that is still operating !!), RDF (yeh well !! ) ...

In fact a modern MFD on a yacht is not far off as capable as some ECDIS on ships .. just a far simpler display ...

The fact is that life has taken GPS( and all the others) on board and so much now uses it ... do not also forget that YOUR GPS is not what Military are using .. its always had two forms ... the commercial and the military ...

The only answer is to create / install a completely different system that does not use sats ... but how long before an adversary jams / spoofs that ? Its fine if near enough to coast to use radar or closer and use mk1 eyeball / compass ... offshore to return to using Sextants ....
Blimey that'll cause a stir ... I now have a vision of all those young 3rd / 2nd mates rushing off to learn to use a sextant !!

 

[Refueler]

I disagree that paper charts are a must in most of the world cruising grounds. They are nice to have, but a must is stretching things. In the vast majority of places there is buoyage, and even without buoyage there's usually enough visual information to dead reckon your way to somewhere safe. From a safety perspective, you don't need precision, you just need to avoid danger and that doesn't require plotting anything on the chart. We all learn this with pilotage notes - keep the lighthouse to port and you'll be safe or keep these things in transit and you're safe, keep the depth over 20m until you can see into the harbour clearly etc.

I hate to say this as a trained professional navigator - but I tend to agree with you ...

When push comes to shove - time is important and fussing over that chart can just be enough to have that sickening thud as you run aground.

OK - I'm an old school navigator - trained to use depth soundings and compass etc - the other 'stuff' is added on top ..

Example : (Pre GPS time) 20,000 ton Bitumen Tanker ..

West Africa ... bad weather so no sights / too far off for coastal on radar, already out of Decca area - proceeding west ... we've been steaming along and we should have seen oil flares way over to stbd ... but nothing ... Its evening 8-12 watch and dark.
Depth sounder on ... hang on a mo - whats that ? We are in 'soundings' ..... called Master and advised that we were in soundings but no sight of Oil Field flares etc.
His reply - what do you suggest ? I suggested an alteration to port just in case to stay clear of land / reducing depths.
Master - OK - agreed.
I turned vessel about 45 deg to port and had watchman keep eyes peeled for oil flares ...
Once I saw depth increasing ... I went to chartroom and stepped out an arc of probability .... (log vs time).
Back out and watchman and I both then caught sight of oil flares fine on PORT bow !
Turned another 20deg heading out further - to clear oil flares ...
Midnight - hand over to 2nd Mate ... we have a discussion and I reckon where we are .. I put a mark on the chart .. he's not convinced.
By now the flares are off stbd bow and we reckon we are safe ... so he turns her stbd to slowly regain intended track.

Next day after we have actually been able to ascertain our position - my mark at midnight was spot on ...

 

[lustyd]

I have been sailing the Thames estuary since 1968 & although I have loads of quirky bits to tell me where to head there is absolutely no way I would consider sailing that area without a chart.( albeit a bit out of date) I am sure that there other areas around the UK & across the channel that some would agree.
True there is buoyage, but try & see a buoy at over .5 of a mile in F6 when it is p..ing with rain, & your glasses are misted up, is not exactly that easy. The echo sounder is great when used with a compass but if you do not know which sandbank it is that you are crossing then you could be in trouble
.
With modern plotters so widely available, I doubt that many actually prepare pilotage notes, other than possibly a list of waypoints & tide times. These being plotted on to the unit . From there on they probably do not bother with writing down lighthouse details, buoyage notes & the like. So if the GPS goes down or the electronic chart info fails, without warning,they would not have the pilotage notes that they studied when they did their day skipper.
.

You completely misunderstood what I said. If it's F6 AND difficult conditions AND GPS has miraculously failed for the first time in history AND you wear glasses then I humbly suggest your best bet is not to try to sail into that area as your safety plan B.
My point was that you're not in any danger if GPS fails. In your scenario, all of the danger comes from your personal choices, not from the lack of GPS or lack of paper charts.

You're over sand, drop the anchor in an appropriate depth.

 

[Daydream believer]

You completely misunderstood what I said. If it's F6 AND difficult conditions AND GPS has miraculously failed for the first time in history AND you wear glasses then I humbly suggest your best bet is not to try to sail into that area as your safety plan B.
My point was that you're not in any danger if GPS fails. In your scenario, all of the danger comes from your personal choices, not from the lack of GPS or lack of paper charts.

You're over sand, drop the anchor in an appropriate depth.

Actually I have had a chart plotter fail without my realising it & that can be VERY dangerous. I also know from personal experience that GPS must be able to give spurious positions to the AIS. Having watched a "target" sail through a light house. So it does not need a total blackout.
When people say that one should not sail in certain conditions that is a crap comment. I have, many times, started off in 15MPH winds (also forecasted) & been confronted with considerably more when half way through the trip. If one is half way between Bradwell & Ramsgate & things kick up then there is not a lot of choice to sail elsewhere.
Does danger come from personal choice. Of course it does. We should all stay at home. Thanks for the advice on that one.

 

[requiem]

ECDIS relies on GPS ... Full Stop.

Heavily utilises, yes. Relies? Technically no.

It's certainly built around the idea of having continuous satellite positioning, but remains usable even in the absence of it. If you lose GPS because a wiring connection corroded through, or you're sailing in an area with jamming, or even if it's working fine but the chart was using an incorrect datum, you can still use the ECDIS (or really any decent ECS system) for navigation. No need to haul out paper.

But, as someone mentioned above, there isn't customer demand for such features even though they are quite simple to implement.

 

[AntarcticPilot]

You completely misunderstood what I said. If it's F6 AND difficult conditions AND GPS has miraculously failed for the first time in history AND you wear glasses then I humbly suggest your best bet is not to try to sail into that area as your safety plan B.
My point was that you're not in any danger if GPS fails. In your scenario, all of the danger comes from your personal choices, not from the lack of GPS or lack of paper charts.

You're over sand, drop the anchor in an appropriate depth.

First of all, GPS has failed many times; it is actually not at all uncommon. It is routinely jammed in some areas for military exercises (the well-known cruising ground of the West Coast of Scotland being a common location for military jamming; they issue warnings when it will happen), and in high latitudes, bad ionospheric conditions can occasionally wipe it out. Of course, military action in some parts of the world will make GPS denial routine. In the early days, this was very common (my colleagues lost several observing sessions for that reason) - the increased constellation has improved matters in that regard, but has not eliminated it entirely. Also, while not relevant to sailing, it is noteworthy that in urban canyons such as those of Hong Kong, the accuracy of GPS is often significantly degraded by multi-path and shadowing effects. I observed this most recently a couple of months ago when the accuracy would go from tens of metres to hundreds of meters depending on the location (you got better positions at crossroads where the sky was visible in two directions). People have posted on these fora effects that are clearly caused by solar flares, where GPS positions became intermittent. GPS can quite often be unavailable or have reduced accuracy.

In general, I agree that buoyage is a good guide, but not always. In rapidly changing areas such as the East Coast, buoys can either drag or be misleading because the bottom has changed since they were last positioned. This is currently the case for the entrance to the River Deben, for example, where following the existing buoys would probably put you aground at some states of the tide. In places like that, local knowledge and the echo sounder become the primary modes of navigation.

No-one should ever depend on a single technique of position fixing; at the very least, sanity checking by eyeball should be a routine matter. I routinely ensure that what I can see matches what my chart-plotter says, and in the event of uncertainty would start taking bearings!