Nobody really needs to know how to navigate anymore, do they?

[Bulawayo]

Im often amazed at the accuracy of charts that are based on information produced in the 19th Century - spot on per the GPS!!

Originally Posted by rognvald

And the assumption is that they are incompetent? You apparently are unaware of the history of navigation for the last 600 years. I'm hoping your remarks were intended to be humorous. Good luck and safe sailing.

[barnakiel]

Originally Posted by Stumble

This might be reasonable... Except that in the strongest storm in centuries (2003) GPS did just fine. The signal was degraded by 100m or so. And modern (i.e. Since 2003) sattelites have been further hardened to survive even stronger storms.

Currently those people in charge of the various systems are saying that GPS signals will degrade by an order of magnitude less than the 2003 storm. On even the worst solar storm on the scale accuracy of the EU system is supposed to degrade from 1cm to 10m.

If I can't figure out where to go with a positional accuracy of 10m, then celestial isn't going to help.

This might be true. Except that judging historical events by the most recent one tells us nothing about the variance. Note we are not really interested in standard deviation here. We want to look the black swan right in the eye.

I remember reading a paper where the power of some solar storms over the last 5000 years was estimated (from geology) at 10 000 (10k) times the power of the 1921 event.

https://en.wikipedia.org/wiki/May_19...magnetic_storm

Given our most incomplete understanding of when such events occur, I think we are but fooling ourselves when we believe a space event of some sort can't take away the whole sat based business in seconds.

The Greek word for such an attitude is, I think, hubris.

b.

[Stumble]

Originally Posted by barnakiel

This might be true. Except that judging historical events by the most recent one tells us nothing about the variance. Note we are not really interested in standard deviation here. We want to look the black swan right in the eye.

I remember reading a paper where the power of some solar storms over the last 5000 years was estimated (from geology) at 10 000 (10k) times the power of the 1921 event.

https://en.wikipedia.org/wiki/May_19...magnetic_storm

Given our most incomplete understanding of when such events occur, I think we are but fooling ourselves when we believe a space event of some sort can't take away the whole sat based business in seconds.

The Greek word for such an attitude is, I think, hubris.

b.

Ya it's not like the people who build GNSS systems have thought about or prepared for a major solar storm...

Oh wait, they have.

Even assuming a worst case storm like the 1859 Carrington event the scientists predict a maximum loss of 10% of GNSS sattelites. So of the 31 currently flying GPS birds we would loose a maximum of 4 (rounding up). So the constellation would be down to 27 operational sattelites. Out of a necessary 24 to provide worldwide <100m accuracy.

So even in a worst case scenario we still have an excess capacity large enough to survive two 500 year events occurring back to back.

But wait, it's even better. Like I keep saying all modern GNSS chips at a minimum work with both US GPS, and Russian GLONASS systems. Since GLONASS has 27 birds in orbit, that would mean every chip has at a minimum access to 58 sattelites, of which 24 are necessary. So the entire system could loose almost 60% of flying and operational sattelites before signal accuracy was degraded.

But wait it gets even better.

The European system Galileo is built on the same frequencies and already has 12 sattelites up with additional ones being launched regularly. And any chip that can receive GPS/GLONASS is also capable of receiving Galileo. So there are currently at least 70 sattelites flying of which 24 are needed. So even a loss rate of 65% could be tolerated without any interruption in world wide accuracy.

So current worst case predictions are a loss of 10% of all sattelites, while the system has a redundancy capable of absorbing a 65% loss.

Ya I am not really worried about it (and we haven't mentioned the Chinese, Japanese, or Indian systems). It is simply not a realistic fear, it may have been one years ago when the systems were first being built. But the world wide consequences of positional accuracy loss is simply too high for modern societies to accept, so the systems have been built to be highly resistant to damage, and with massive amounts of redundancy.

If you are worried about lightning then store a GPS reciever in a faraday cage with a lot of extra batteries (I certainly do). If you are worried about the crashing of the entire world wide GNSS system then you need to relax. It simply isn't going to happen.

All that said, I still want paper charts onboard. But I don't carry my sextant. There is simply no electronic comparable to being able to lay out a large sheet of paper and take in a wide angle view.

[Dockhead]

Originally Posted by Stumble

Ya it's not like the people who build GNSS systems have thought about or prepared for a major solar storm...

Oh wait, they have.

Even assuming a worst case storm like the 1859 Carrington event the scientists predict a maximum loss of 10% of GNSS sattelites. So of the 31 currently flying GPS birds we would loose a maximum of 4 (rounding up). So the constellation would be down to 27 operational sattelites. Out of a necessary 24 to provide worldwide <100m accuracy.

So even in a worst case scenario we still have an excess capacity large enough to survive two 500 year events occurring back to back.

But wait, it's even better. Like I keep saying all modern GNSS chips at a minimum work with both US GPS, and Russian GLONASS systems. Since GLONASS has 27 birds in orbit, that would mean every chip has at a minimum access to 58 sattelites, of which 24 are necessary. So the entire system could loose almost 60% of flying and operational sattelites before signal accuracy was degraded.

But wait it gets even better.

The European system Galileo is built on the same frequencies and already has 12 sattelites up with additional ones being launched regularly. And any chip that can receive GPS/GLONASS is also capable of receiving Galileo. So there are currently at least 70 sattelites flying of which 24 are needed. So even a loss rate of 65% could be tolerated without any interruption in world wide accuracy.

So current worst case predictions are a loss of 10% of all sattelites, while the system has a redundancy capable of absorbing a 65% loss.

Ya I am not really worried about it (and we haven't mentioned the Chinese, Japanese, or Indian systems). It is simply not a realistic fear, it may have been one years ago when the systems were first being built. But the world wide consequences of positional accuracy loss is simply too high for modern societies to accept, so the systems have been built to be highly resistant to damage, and with massive amounts of redundancy.

If you are worried about lightning then store a GOS reciever in a faraday cage with a lot of extra batteries (I certainly do). If you are worried about the crashing of the entire world wide GNSS system then you need to relax. It simply isn't going to happen.

All that said, I still want paper charts onboard. But I don't carry my sextant. There is simply no electronic comparable to being able to lay out a large sheet of paper and take in a wide angle view.

In my opinion, this is the most rational view expressed on the subject so far in this thread.

In simple terms, and also to bring it back to the topic of the OP:

1. The risk of all GNSS systems losing all their function is very small indeed (in my opinion, war is the main risk), as Greg has shown.

2. The consequence of losing all GNSS function is not actually all that disastrous, if it did occur.

3. Keep a GNSS receiver in a cookie tin somewhere in case of a lightning strike. Maybe also your obsolete IPlod with INavX and some outdated charts on it.

4. Have paper charts, at least small scale ones.

5. Learn celestial, by all means, if you have time and inclination. But vastly more important than celestial is proper knowledge of pilotage, DR, and chart work. Even without failure of GNSS, these skills are valuable.

6. Relax and have another gin & tonic. No panic is needed on this subject. As RWidman said -- if you can't deal with an electronics failure, if it occurs, maybe you should consider an RV? This is basic seamanship, and I'm sure that everyone involved in this thread, at least, would do just fine.


Edit: To our friend Barny: It's not hubris, to rely on something, which is objectively reliable. If we couldn't rely on various reliable things, so avoiding hubris by this definition, we would never leave the dock. We rely, for example, on fiberglass not suddenly becoming porous, and don't carry an extra hull skin with us. Is that hubris? Of course not.

[SV DestinyAscen]

Originally Posted by Stumble

All that said, I still want paper charts onboard. But I don't carry my sextant. There is simply no electronic comparable to being able to lay out a large sheet of paper and take in a wide angle view.

Agreed - maybe it is age, but I really struggle with using the screen to get a big picture, and I'm never sure what detail is being filtered out at which zoom levels.

If someone would make a chart table with the kindle screen, they should be rich.

[Bulawayo]

Good idea.

Originally Posted by Dockhead

Why don't you start a new thread in the Electronics section? I'll post there, and you'll get a lot of feedback from others as well.

Sent from my D6633 using Cruisers Sailing Forum mobile app

[Dockhead]

Originally Posted by SV DestinyAscen

Agreed - maybe it is age, but I really struggle with using the screen to get a big picture, and I'm never sure what detail is being filtered out at which zoom levels.

If someone would make a chart table with the kindle screen, they should be rich.

It's not age. You simply cannot get a big picture view of a largeish piece of water with a vector chart on a small screen. Just ask the Team Vestas guys.

I cruise 10 to 12 countries every year, and keeping paper of every area would be almost impossible. As it is, I have paper charts under every bunk.

Therefore, I have been working with OpenCPN on a large high resolution monitor and raster charts. It can be made to be ALMOST as good as paper, with the enormous advantage that you can keep 10,000 charts on your hard drive without sinking the boat down on her lines. Certain chart work (not quite all of it yet) can also be done very well on O. And creating routes, of course, is far easier, than with paper.

[barnakiel]

Originally Posted by Stumble

Ya it's not like the people who build GNSS systems have thought about or prepared for a major solar storm...

Oh wait, they have.

(...)

So current worst case predictions are a loss of 10% of all sattelites, while the system has a redundancy capable of absorbing a 65% loss.

(...)

I am on your wavelength.

I think it is possible that you assumption of how strong the events may get and when they may occur are way off when you think about the scientific method.

The worst case observed is not the worst case possible. Think about our observation time span as something in the range of 1/100000^100000 of all solar events in the history of humanity on Earth. So, OK, we get one bad ass event every 500 years, but sometimes we get two of them in one solar cycle!

That events are statistically occurring one per 500 years does not mean next two will not happen within 10 years. We are often not intuitively aware of this, unless we take our statistics beyond plain averages and look for higher derivatives.

Strong solar events are believed to be 10 thousand times stronger than any of the ones we could observe over last 200 years or so. It is believed they can actually modify the DNA of life forms on our planet. Some scientist point to them as to possible explanation of why evolution was in fact but a series of revolutions spaced with long terms of stabilistaion and normalisation. Thinks of nuclear wars once every million years. A Chernobyl acceleration now and then.

We do have huge tendency to underestimate the frequency and reach of 'rare' events, be it finance, social history or astrophysics. It is a well known bias.

You may have some fun reading one of Taleb's books. He discusses our faulty intuitions and gives good pointers on how to overcome our biases. I have not read the Antifragile yet. Waiting for a free copy on one of sailors book swap days. ;-) Given how rare they are on swaps, I might rethink my bias and go buy my copy.

Indeed, recent satellites are better secured against solar storms than older ones. Lessons, lessons everywhere.

This would be real cool to be able to sit round the fire one day and talk about all those amazing things related to navigation and life!

Big hug,
b.

[Adelie]

Originally Posted by rwidman

Of course they work. Unless you just want to argue.

So rather than reply as to why my reasoning is incorrect, your reply is that I am just trying to be a troll?

Isn't that more or less an ad hominem attack?

[Stumble]

Barnacle,

There is no question that just because something hasn't happened, or we have no record of it, means that it can't happen. But at some point you have to make the decision that the risk of X is low enough that you can dispense with resolving it. It's a decision of how much risk is acceptable.

Sure it's possible that a solar storm so strong it will knock out all the sattelites could occur. But there is no evidence of such a strong storm occurring for at least the last 1,200 years. And the strongest solar flare we have any record of was about 10 times the strength of the Carrington event which may or may not be a solar flare (it's a C14 spike which could be a solar flare, but could also be from a lot of things).

So what would be the effect of a super flare like this on current sattelites? I really have no idea. The details of how hardened the systems really are is beyond me.

But if we assume that there is a 1/1200 change per year of a solar storm large enough to take down the entire system. What the chance that you will drop your sextant overboard while taking a noon site? Let's assume it's a 1:10 year chance...

By any reasonable logic if you are going to guard against a 1:1200 chance, then you should also guard against a 1:10 chance... So how many spare sextants are you going to bring with you?

And in the event of a solar storm this strong any electronics are probably toast as well, so how many manual gimbled clocks are you going to bring with you?

And since it's a boat what's the chance the reduction tables will get damaged by water, fire... So how many copies of them are you going to bring with you?


My point is not that there is no likelyhood that all the sattelite nav systems could go down. But that the likelyhood is so remote it is always statistically safer to bring another GPS than it is to worry about celestial navigation. Unless you need to be able to operate in the event of an all out global war where you are a military target.

The USN is special in that they really do need to be able to operate in a world where people are activly trying to attack their system. Wether it's by hacking into the computer systems to damage the navigation systems, or activly jam GPS signals, or keep functioning after all the GNSS sattelites have been shot down intentionally.

[Bulawayo]

Greg, solar flares are but one issue. I would also question the accuracy of the 1200 years quoted; there was no reason to note such events 1200 years ago by most societies and those that did had no way of establishing its relevance against todays systems.
The GPS system has been lost before and the odds of happening again increase with the longer it holds up. However, individually, the most likelihood of GPS happening is a lightning strike. Even your second hand GPS in a biscuit tin wont necessarily help you if you are mid-ocean unless you have somehow retained a means of recharginging it AND it has the appropriate charts installed on it. You will probably be relying on it for a position fix every 24 hours but that fix needs to be plotted somewhere/somehow. Back to needing a paper chart.
The question of paper copies (charts/tables) being water destroyed or of gimballed time pieces is rather misleading. Ive lost plenty of documents due to a hatch leaking or more often being left open etc but never charts or tables as they are kept far from a water source. My watch is also very accurate - more than adequate. Even the ships clock is reliable and I know how many minutes it looses each week between wind ups.
I also accept that electronics are reliable, just as the lightning strikes are - someone/something is being struck regularly.
It shall be interesting to know how the intergalatic Captain Cooks/Magellans of the future shall manage once the heavens are opened.
Barnacle does have a point, perhaps just not the way some others see it.

Originally Posted by Stumble

Barnacle,

There is no question that just because something hasn't happened, or we have no record of it, means that it can't happen. But at some point you have to make the decision that the risk of X is low enough that you can dispense with resolving it. It's a decision of how much risk is acceptable.

Sure it's possible that a solar storm so strong it will knock out all the sattelites could occur. But there is no evidence of such a strong storm occurring for at least the last 1,200 years. And the strongest solar flare we have any record of was about 10 times the strength of the Carrington event which may or may not be a solar flare (it's a C14 spike which could be a solar flare, but could also be from a lot of things).

So what would be the effect of a super flare like this on current sattelites? I really have no idea. The details of how hardened the systems really are is beyond me.

But if we assume that there is a 1/1200 change per year of a solar storm large enough to take down the entire system. What the chance that you will drop your sextant overboard while taking a noon site? Let's assume it's a 1:10 year chance...

By any reasonable logic if you are going to guard against a 1:1200 chance, then you should also guard against a 1:10 chance... So how many spare sextants are you going to bring with you?

And in the event of a solar storm this strong any electronics are probably toast as well, so how many manual gimbled clocks are you going to bring with you?

And since it's a boat what's the chance the reduction tables will get damaged by water, fire... So how many copies of them are you going to bring with you?


My point is not that there is no likelyhood that all the sattelite nav systems could go down. But that the likelyhood is so remote it is always statistically safer to bring another GPS than it is to worry about celestial navigation. Unless you need to be able to operate in the event of an all out global war where you are a military target.

The USN is special in that they really do need to be able to operate in a world where people are activly trying to attack their system. Wether it's by hacking into the computer systems to damage the navigation systems, or activly jam GPS signals, or keep functioning after all the GNSS sattelites have been shot down intentionally.

[charliehows]

in the 60's my father and 4 of his mates used to pile onto a 32' boat and sail off to various tiny little dots in the pacific - he was cook and navigator and i know he worried a lot about being close enough in his calcs. not to pass their target without it ever coming up on the horizon - he used to be pretty proud of bringing them up dead ahead -
BUT - like any good sailor he would have taken to gps in a heartbeat - resourcefulness is the first rule for a sailor - for the same reason, any problems with the gps system wouldnt make much difference, one would simply adapt with whatever the next tool in the box happens to be.
For most people AIS is probably a more important tool than gps - the oceans, particularly around their edges, are getting pretty crowded, knowing where you are is less important than knowing some 100,000 ton leviathon is bearing down on you at 15 knots with one dozy halfwit sitting on the helm staring at a chartplotter

[Pelagic]

.... When people say they rely on GPS....

In the simplest example....
does that mean that they enter a waypoint from some chart reference and select 'Goto' and follow that course checking beforehand that there are no dangers near the course line?

I am curious if that is the method used by most.

I also wonder if that type of reliance contributed to Jose Hernandez's death and 2 others, when failing to clear the breakwater at night

[JPA Cate]

Originally Posted by Pelagic

.... When people say they rely on GPS....

In the simplest example....
does that mean that they enter a waypoint from some chart reference and select 'Goto' and follow that course checking beforehand that there are no dangers near the course line?

I am curious if that is the method used by most.

I also wonder if that type of reliance contributed to Jose Hernandez's death and 2 others, when failing to clear the breakwater at night

Failure to keep a lookout. Possible alcohol and/or other drugs involved as well?

Somebody had poor judgment, and three paid a dreadful price for that.

As to how some people use GPS, one thing we see is that people tend to place their waypoints at their desired distance off headlands.....so there are huge congregations of vessels at these points. If you move your WP a couple of miles further out, there's much less traffic.

And of course, if you don't have paper charts, you can easily have a Team Vespas moment, 'cause wee tiny screens displays are hard to see the little dots on. Easy to spot and mark on a paper chart.

Ann

[AbelCMann]

Those who would readily throw away celestial navigational skills will readily throw away pilotage skills as well. Blind faith in the wondrous capabilities that computers can achieve does not equate with a true relationship and knowledge of where you truly are. And why are you out there anyway, if not to connect more closely in a real and experiential way?
Know where you are because you understand it, not because your device gives you permission to act.