7 ms·

I saw some rumblings (can't find an article) that there's interest in restarting LORAN to provide an alternative to GPS for this reason.

by teeray 17d ago

laruss5 17d ago
[dead]
budman1 17d ago
LORAN can be jammed.
- teeray 17d ago
  Well certainly, no one thing is impervious. But if you have GPS, LORAN, VORs, NDBs, astronavigation, etc. you have many more options at your disposal and present a much more complex attack target.
  - butvacuum 16d ago
    It's 2026: we have more ways to defeat jamming, or make it irrelevant, at unit costs trivial for commercial and most private applications. 1) atomic clocks can be smaller than a closed fist and allow GPS to work with 3 satalites with ocassional drops to 2. 2) the same clocks can be used to filter out radio sources from the wrong direction. 3) star navigation (commercial is often above weather, most weather is clear in some IR bands) 4) Terain following (easy to store maps now) 5) Inertial. 6) magnetic When combined it is very hard to break the position fix. I expect the issue with the system is it's a military tech. with all it's that'll associated legal problems. After all. it'd bypass most the protections built into GPS modules.
    - wbl 16d ago
      And the military has JDAM with HOJ as a solution for jamming
      - butvacuum 16d ago
        I was thinking G-man and a suprise helicopter on your lawn. The government hasn't made a spectical of throwing the book at a jammer recently.
  - mschuster91 16d ago
    > astronavigation Good luck finding a pilot trained on doing this, or an aircraft with high enough window cutouts that allow for the use of a sextant. Old Boeings had them [1], but no modern aircraft does. I think even among navies you'll be hard pressed to find a navigator who still can do astronavigation. IIRC even the US Navy discontinued astronavigation, but recently-ish reintroduced training for it again. [1] https://virginflightdeck.blogspot.com/2010_09_01_archive.html https://virginflightdeck.blogspot.com/2010_09_01_archive.htm...
    - teeray 16d ago
      > Good luck finding a pilot trained on doing this Not necessary. ICBMs have been able to do this autonomously for a very long time [0] [0] https://en.wikipedia.org/wiki/Celestial_navigation https://en.wikipedia.org/wiki/Celestial_navigation
    - leonidasrup 16d ago
      In the 21st century you don't do astronavigation by hand, you use cameras, computers and software. Astro-inertial guidance is used for example in submarine-launched ballistic missiles. "Astro-inertial guidance, or stellar-inertial guidance, is a sensor fusion-information fusion of inertial guidance and celestial navigation. It is usually employed on submarine-launched ballistic missiles. Unlike silo-based intercontinental ballistic missiles, whose launch point does not move and thus can serve as a reference, SLBMs are launched from moving submarines, which complicates the necessary navigational calculations and increases circular error probable. Stellar-inertial guidance is used to correct small position and velocity errors that result from launch condition uncertainties due to errors in the submarine navigation system and errors that may have accumulated in the guidance system during the flight due to imperfect instrument calibration." https://en.wikipedia.org/wiki/Missile_guidance https://en.wikipedia.org/wiki/Missile_guidance
      - mschuster91 16d ago
        Yeah but good luck getting that approved for new airliner designs, much less retrofitting it into existing airliners. For the older ones, you'd probably need to rework half their computers.
- cyberax 16d ago
  Not really. It uses 2MHz band, with the wavelength of around 160m. This means that it's easy to receive via a ferrite bar antenna but hard to transmit. You need an antenna of at least around 40m size for that to be efficient.
  - lstodd 16d ago
    Even a 160m guy-wire tower is cheap. 40m.. my friend installed 32m one just to have better internets, not exactly out of pocket cash, but nothing compared to say swapping a car.
    - cyberax 16d ago
      Sure, but such an antenna will be extremely conspicuous and easy to triangulate. You can't install it covertly. Meanwhile, GPS can be jammed or spoofed with a briefcase-sized device for a couple of kilometers around you.
      - lstodd 15d ago
        I thought we were talking about how eLoran is cheap enough. But if you are about jamming, well. Either discontinue AIS/ADS-B or directed VHF jammers are not that conspicious. Not even a PESA, 60s tech.
    - KaiserPro 15d ago
      yes, but trying to pump 25kw through that without it being obvious is a lot harder.
- jacquesm 16d ago
  Not so simple. For one the distances to the transmitter are much smaller, for another the amount of power available to the transmitters is pretty much whatever you want to hook it up to, whereas GPS satellites are on a pretty strict power budget. On the reception side the power levels are many orders of magnitude apart.
- leonidasrup 16d ago
  "In trials conducted by the General Lighthouse Authorities of UK and Ireland, a 1.5W radio jammer was able to knock out GPS signals over a range of 30 kilometers. However, to do the same to the Loran system, you'd need a 40ft tower — and around 25kW of juice to power it." https://www.engadget.com/2013-01-21-uk-eloran-navigation-system-gps-substitute.html https://www.engadget.com/2013-01-21-uk-eloran-navigation-sys...
throw0101d 16d ago
See UK and France: * https://insidegnss.com/uk-and-france-renew-ties-resilient-pnt-eloran-a-key-part/ https://insidegnss.com/uk-and-france-renew-ties-resilient-pn...
ianburrell 16d ago
eLoran has been proposed as more accurate version of LORAN competitive with GPS. The Wikipedia page says that China has deployed an eLoran network but I can't tell if used for navigation or just high-precision timing.
- geerlingguy 15d ago
  The US has done tests with eLoran as well. The receivers are quite expensive and the signal isn't permanent yet, so it's more of a lab thing right now. Also experiments with BPS (Broadcast Positioning System) using high power TV transmitters to distribute time and position in urban areas (very hard to overpower that signal).

I saw some rumblings (can't find an article) that there's interest in restarting LORAN to provide an alternative to GPS for this reason.

by teeray 17d ago

I saw some rumblings (can't find an article) that there's interest in restarting LORAN to provide an alternative to GPS for this reason.

laruss5 17d ago

[dead]

budman1 17d ago

LORAN can be jammed.

teeray 17d ago
Well certainly, no one thing is impervious. But if you have GPS, LORAN, VORs, NDBs, astronavigation, etc. you have many more options at your disposal and present a much more complex attack target.
- butvacuum 16d ago
  It's 2026: we have more ways to defeat jamming, or make it irrelevant, at unit costs trivial for commercial and most private applications. 1) atomic clocks can be smaller than a closed fist and allow GPS to work with 3 satalites with ocassional drops to 2. 2) the same clocks can be used to filter out radio sources from the wrong direction. 3) star navigation (commercial is often above weather, most weather is clear in some IR bands) 4) Terain following (easy to store maps now) 5) Inertial. 6) magnetic When combined it is very hard to break the position fix. I expect the issue with the system is it's a military tech. with all it's that'll associated legal problems. After all. it'd bypass most the protections built into GPS modules.
  - wbl 16d ago
    And the military has JDAM with HOJ as a solution for jamming
    - butvacuum 16d ago
      I was thinking G-man and a suprise helicopter on your lawn. The government hasn't made a spectical of throwing the book at a jammer recently.
- mschuster91 16d ago
  > astronavigation Good luck finding a pilot trained on doing this, or an aircraft with high enough window cutouts that allow for the use of a sextant. Old Boeings had them [1], but no modern aircraft does. I think even among navies you'll be hard pressed to find a navigator who still can do astronavigation. IIRC even the US Navy discontinued astronavigation, but recently-ish reintroduced training for it again. [1] https://virginflightdeck.blogspot.com/2010_09_01_archive.html https://virginflightdeck.blogspot.com/2010_09_01_archive.htm...
  - teeray 16d ago
    > Good luck finding a pilot trained on doing this Not necessary. ICBMs have been able to do this autonomously for a very long time [0] [0] https://en.wikipedia.org/wiki/Celestial_navigation https://en.wikipedia.org/wiki/Celestial_navigation
  - leonidasrup 16d ago
    In the 21st century you don't do astronavigation by hand, you use cameras, computers and software. Astro-inertial guidance is used for example in submarine-launched ballistic missiles. "Astro-inertial guidance, or stellar-inertial guidance, is a sensor fusion-information fusion of inertial guidance and celestial navigation. It is usually employed on submarine-launched ballistic missiles. Unlike silo-based intercontinental ballistic missiles, whose launch point does not move and thus can serve as a reference, SLBMs are launched from moving submarines, which complicates the necessary navigational calculations and increases circular error probable. Stellar-inertial guidance is used to correct small position and velocity errors that result from launch condition uncertainties due to errors in the submarine navigation system and errors that may have accumulated in the guidance system during the flight due to imperfect instrument calibration." https://en.wikipedia.org/wiki/Missile_guidance https://en.wikipedia.org/wiki/Missile_guidance
    - mschuster91 16d ago
      Yeah but good luck getting that approved for new airliner designs, much less retrofitting it into existing airliners. For the older ones, you'd probably need to rework half their computers.
cyberax 16d ago
Not really. It uses 2MHz band, with the wavelength of around 160m. This means that it's easy to receive via a ferrite bar antenna but hard to transmit. You need an antenna of at least around 40m size for that to be efficient.
- lstodd 16d ago
  Even a 160m guy-wire tower is cheap. 40m.. my friend installed 32m one just to have better internets, not exactly out of pocket cash, but nothing compared to say swapping a car.
  - cyberax 16d ago
    Sure, but such an antenna will be extremely conspicuous and easy to triangulate. You can't install it covertly. Meanwhile, GPS can be jammed or spoofed with a briefcase-sized device for a couple of kilometers around you.
    - lstodd 15d ago
      I thought we were talking about how eLoran is cheap enough. But if you are about jamming, well. Either discontinue AIS/ADS-B or directed VHF jammers are not that conspicious. Not even a PESA, 60s tech.
  - KaiserPro 15d ago
    yes, but trying to pump 25kw through that without it being obvious is a lot harder.
jacquesm 16d ago
Not so simple. For one the distances to the transmitter are much smaller, for another the amount of power available to the transmitters is pretty much whatever you want to hook it up to, whereas GPS satellites are on a pretty strict power budget. On the reception side the power levels are many orders of magnitude apart.
leonidasrup 16d ago
"In trials conducted by the General Lighthouse Authorities of UK and Ireland, a 1.5W radio jammer was able to knock out GPS signals over a range of 30 kilometers. However, to do the same to the Loran system, you'd need a 40ft tower — and around 25kW of juice to power it." https://www.engadget.com/2013-01-21-uk-eloran-navigation-system-gps-substitute.html https://www.engadget.com/2013-01-21-uk-eloran-navigation-sys...

throw0101d 16d ago

See UK and France: * https://insidegnss.com/uk-and-france-renew-ties-resilient-pnt-eloran-a-key-part/ https://insidegnss.com/uk-and-france-renew-ties-resilient-pn...

ianburrell 16d ago

eLoran has been proposed as more accurate version of LORAN competitive with GPS. The Wikipedia page says that China has deployed an eLoran network but I can't tell if used for navigation or just high-precision timing.

geerlingguy 15d ago
The US has done tests with eLoran as well. The receivers are quite expensive and the signal isn't permanent yet, so it's more of a lab thing right now. Also experiments with BPS (Broadcast Positioning System) using high power TV transmitters to distribute time and position in urban areas (very hard to overpower that signal).