We also usually seek secluded nice anchorages among the rocky unbuoyed waters in the northern Baltic. But I think if our electrics were down and/or GPS was massively disrupted, I’d be ok going into a bigger, well-marked harbour to get things back online.
That was my point - the update process .....
I had a whimsical habit among the rocks off Sweden of referring to the buoys as having been put there to protect the rocks.
There was quite a bit of this stuff going on in 2022. Quick example:
Being pedantic, two articles about GPS don’t address his question about Glonass
Fair point. And obviously my post he was replying to was talking about GPS disruption, not Glonass. Though I guess in a lot of places (including this thread), people use the term GPS to cover the various other GNSS constellations as well.
That matters for sophisticated techniques like spoofing or selective availability, but it is also worth noting that all GNSS signals are ridiculously weak, and crude noise jamming will obliterate all and any GNSS system quite easily. I understand that there are such systems available on the clandestine market to allow people like truck drivers to defeat tracking devices! And of course, the big noise generator in the sky can do a good job if it's in a bad mood. In the polar regions, GNSS is occasionally blanked by ionospheric disturbances caused by solar activity. Temperate and tropical regions are well protected by the Earth's magnetic field, but it would only take a solar mass ejection hitting the Earth full on and there would be no GNSS anywhere. Ionospheric disturbances can also cause inaccuracies by changing the Total Electron Content of the ionosphere, thus changing the time of flight of the signals. This is less of a problem these days with a full constellation and several systems and can be corrected for by dual frequency systems or by broadcast corrections, but I have attended presentations where researchers were using delays to GNSS signals to determine the TEC of the ionosphere! There are also situations where the ionospheric TEC changes rapidly, and this is less able to be corrected.
But those sailing in high latitudes should be aware that GNSS may not be as reliable as in low latitudes. Again, the high degree of redundancy in today's systems lessens the problem, but it doesn't make it go away.
Would a pole swap not be predicted, or at any rate, be preceeded by a period of instability that raised the possibility? And assuming that it didn’t coincide with an outage of GNSS, for me it would just make reacting to wind shifts when racing harder. Cruising, my magnetic compass is a backup, not primary nav. We’d have to rely on GPS for our heading. The only reason I have a heading sensor is to improve wind data.
I don’t think we know with any certainty what will happen. The poles are moving faster than predicted, making older charts or those without updates misleading to those relying on them for navigation. I just wanted to highlight that the old ways aren’t infallible
Plenty of people failed at them, for sure. As for magnetic north corrections, I have never seen that done. I do have some 30 year old charts, but as they are stuck to the wall in the stairway to the loft room, it's not something that concerns me personally.
Compass corrections aren't much affected. There are TWO magnetic poles; one is the pole towards which compasses point; the other is the one where the magnetic field lines are vertical. They don't coincide because the Earth's magnetic field is complicated (it isn't a simple dipole field like that of a bar magnet). The latter is the one that is moving quickly; the former (which is what matters when it comes to deviation and variation) is not. So it isn't a problem.
But that is even worse from a navigation perspective. If tomorrow north became south, we could just swap everything over. If it takes many years it could be chaos, and we don't know for sure whether the change will be predictable since we've never seen it happening before!
