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> The development of modern technology, including GPS, means lighthouses are no longer essential for navigation, said John Kelly of the GSA’s office of real pro

> The development of modern technology, including GPS, means lighthouses are no longer essential for navigation, said John Kelly of the GSA’s office of real property disposition. And while the Coast Guard often maintains aids to navigation at or near lighthouses, the structures themselves are often no longer mission critical. Hopefully this modern technology and these aids to navigation don't all rely on space based hardware to function otherwise if there's a hot war in space or otherwise a case of Kessler Syndrome then we have a lot of ship wrecks baked into the equation.

_moof 3y ago
If (when) the GPS fails you can do pretty well with radar and a depth sounder.
- bookofjoe 3y ago
  https://www.thevintagenews.com/2017/02/23/depth-sounding-techniques-that-preceded-the-modern-day-sonar-technology/?chrome=1&D2c=1&A1c=1 https://www.thevintagenews.com/2017/02/23/depth-sounding-tec...
ianburrell 3y ago
GPS is well above where Kessler Syndrome would be a problem. GPS orbits in medium-earth orbit with 12-hour period. The only other thing in area are other navigation constellations and there is much more space than LEO. Also, GPS is high enough that would require special and large anti-satellite weapons to take out. There was a post this week, https://news.ycombinator.com/item?id=36043377 https://news.ycombinator.com/item?id=36043377, about alternatives to GPS.
somerandomqaguy 3y ago
I'd imagine there's options if every space based constellation was knocked out. Ground based GPS transmitters are a thing (https://en.wikipedia.org/wiki/Pseudolite https://en.wikipedia.org/wiki/Pseudolite) and I'd imagine could be very quickly erected. And DARPA is putting significant money into GPS denied navigation systems as well: https://www.darpa.mil/news-events/2014-07-24 https://www.darpa.mil/news-events/2014-07-24 Assuming that modern semi conductor manufacturing wasn't knocked out at the same time, ship navigation would probably be fixed in a hurry.
- throw0101b 3y ago
  > […] ship navigation would probably be fixed in a hurry. Just make sure you have a sextant, an almanac, and a UTC-synced watch on-board and you're fine: * https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-back-navigation-by-the-stars-for-officers https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-bac... * https://www.popularmechanics.com/military/research/a36078957/celestial-navigation/ https://www.popularmechanics.com/military/research/a36078957...
  - bookofjoe 3y ago
    Will UTC still be functioning?
  - HeyLaughingBoy 3y ago
    If you're close enough to shore that a missing lighthouse would be an issue, a sextant wouldn't be very helpful (OK, you could use horizontal sextant angles, but those are not well known). An alidade and a compass will do just fine.
stn8188 3y ago
Certainly the GPS navigation equipment on board a vessel could fail in the event GPS signals are jammed or otherwise inoperable. As for the navigation aids themselves, as of a decade ago there were no GPS devices in the aids (though a GPS receiver is used for precise placement of buoys). The navigation lights in (or near) the lighthouse structures use large lead-acid batteries for energy storage, and a large solar array for charging. When I left, we were in the process of converting many of the aids to LED lamps, which use far less energy (thus reducing the size requirements of the batteries and solar arrays). For the larger lamps, we had a pretty complex box with the electrical equipment to manage charging, flash patterns, backup lights, etc. (the old "SACIII" aka Solar Aid Controller). The electrical systems are all pretty neat but really don't need the "shelter" of a lighthouse, and many lights are on simple towers.
foxes 3y ago
If we start shooting satellites out the sky I don't really think you will have to worry about ships wrecking themselves for very long.

_moof 3y ago

If (when) the GPS fails you can do pretty well with radar and a depth sounder.

bookofjoe 3y ago
https://www.thevintagenews.com/2017/02/23/depth-sounding-techniques-that-preceded-the-modern-day-sonar-technology/?chrome=1&D2c=1&A1c=1 https://www.thevintagenews.com/2017/02/23/depth-sounding-tec...

ianburrell 3y ago

GPS is well above where Kessler Syndrome would be a problem. GPS orbits in medium-earth orbit with 12-hour period. The only other thing in area are other navigation constellations and there is much more space than LEO. Also, GPS is high enough that would require special and large anti-satellite weapons to take out. There was a post this week, https://news.ycombinator.com/item?id=36043377 https://news.ycombinator.com/item?id=36043377, about alternatives to GPS.

somerandomqaguy 3y ago

I'd imagine there's options if every space based constellation was knocked out. Ground based GPS transmitters are a thing (https://en.wikipedia.org/wiki/Pseudolite https://en.wikipedia.org/wiki/Pseudolite) and I'd imagine could be very quickly erected. And DARPA is putting significant money into GPS denied navigation systems as well: https://www.darpa.mil/news-events/2014-07-24 https://www.darpa.mil/news-events/2014-07-24 Assuming that modern semi conductor manufacturing wasn't knocked out at the same time, ship navigation would probably be fixed in a hurry.

throw0101b 3y ago
> […] ship navigation would probably be fixed in a hurry. Just make sure you have a sextant, an almanac, and a UTC-synced watch on-board and you're fine: * https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-back-navigation-by-the-stars-for-officers https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-bac... * https://www.popularmechanics.com/military/research/a36078957/celestial-navigation/ https://www.popularmechanics.com/military/research/a36078957...
- bookofjoe 3y ago
  Will UTC still be functioning?
- HeyLaughingBoy 3y ago
  If you're close enough to shore that a missing lighthouse would be an issue, a sextant wouldn't be very helpful (OK, you could use horizontal sextant angles, but those are not well known). An alidade and a compass will do just fine.

stn8188 3y ago

Certainly the GPS navigation equipment on board a vessel could fail in the event GPS signals are jammed or otherwise inoperable. As for the navigation aids themselves, as of a decade ago there were no GPS devices in the aids (though a GPS receiver is used for precise placement of buoys). The navigation lights in (or near) the lighthouse structures use large lead-acid batteries for energy storage, and a large solar array for charging. When I left, we were in the process of converting many of the aids to LED lamps, which use far less energy (thus reducing the size requirements of the batteries and solar arrays). For the larger lamps, we had a pretty complex box with the electrical equipment to manage charging, flash patterns, backup lights, etc. (the old "SACIII" aka Solar Aid Controller). The electrical systems are all pretty neat but really don't need the "shelter" of a lighthouse, and many lights are on simple towers.

foxes 3y ago

If we start shooting satellites out the sky I don't really think you will have to worry about ships wrecking themselves for very long.