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Cheap GPS jammers are filling the world with navigation dead zones

wsj.com

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Re: Cheap GPS jammers are filling the world with navigation dead zones

#41

Post by leonidasrup »

toomuchtodo wrote: post #23
jacquesm wrote: post #16

Earlier quoted context omitted.

And LORAN. But it may make a come-back. GPS signals are just incredibly weak so it takes next to nothing to drown them out, easier still if you are above the receiver.

I would be curious on and interested in guidance from a GNSS expert on what the risk profile is when you're using jam resistant frequencies with a multi GNSS constellation chipset (GPS, Galileo, BeiDou), WAAS (GNSS corrections received via satellite), and when close enough to airports that support it, LAAS (GNSS corrections broadcast from airports). Follow up questions would be what countermeasures are available to b…

Because GPS and other GNSS have only a very weak signal strength there are no jam resistant frequencies, you can jam them all very efficiently, or you can jam them very efficiently in selective way (jam BeiDou, but not GPS).

GPS was jammed even as early as Iraq war.

"Coalition troops also got a glimpse of GPS’s greatest weakness during the Gulf War. Iraqi forces installed jammers, for example, on top of landmarks such as Saddam Hussein’s palaces to prevent them from being hit, Mastalir says. This helped the military realize early on that it would have to further develop its laser-guided munitions and other weapons that acquire targets when GPS is unavailable"

https://web.archive.org/web/20160208233555/http://www.scient...

Re: Cheap GPS jammers are filling the world with navigation dead zones

#42

Post by michaelt »

jshier wrote: post #25
bronco21016 wrote: post #9

Whats really sad for aviation is there was already an extensive network of ground based navaids. As GPS has proliferated, they've slowly been decommissioned as they age out to save on cost. I'm specifically referring to VORs which provide azimuth and range to station. GPS is fantastic and as a primary source everyone loves the benefits it brings. However, in a century of aviation, everyone has kinda sorted out that y…

Seems like we'd need a modern version that's less susceptible to jamming, otherwise aren't we just replacing one jammable service with another?

There are two types of GPS jamming.

There's GPS jamming by the military, mostly in war zones. This seldom effects airliners because they steer clear of active war zones.

Then there's GPS jamming by delivery drivers who don't want their boss watching over their shoulder all the time. When the article mentions jammers as small as a cellphone and costing less than $100, those are sold to drivers.

Delivery drivers don't jam LORAN or VOR, though - so it's not jammed by the second type.

Re: Cheap GPS jammers are filling the world with navigation dead zones

#43

Post by leonidasrup »

budman1 wrote: post #6
teeray wrote: post #2

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.

LORAN can be jammed.

"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-sys...

Re: Cheap GPS jammers are filling the world with navigation dead zones

#44

Post by buildsjets »

verelo wrote: post #20
buildsjets wrote: post #10

Earlier quoted context omitted.

VOR is extremely short range and requires an extraordinary number of transmitters to provide any volume of coverage. Additionally it cannot provide coverage over oceanic areas. We USED TO have a nearly global long-range land based navigation system called LORAN, which only required one master station and a few remote stations to provide continent-scale coverage. But it was decommissioned in a cost savings move after…

On VOR: It's also a PITA to use, and for inexperienced people, or someone who rarely uses it, they can confuse flying towards and away from the station.

If you are a general aviation goober like me, flying a 1960's propeller airplane, sure, that is true.

However, in a modern commercial aircraft, all position sources including VOR-DMEs, GPS, and IRS are cross-compared by the flight management system and turned into a latitude, longitude, and circular error of probability. There is no TO/FROM flag to worry about in a 777, and no reverse sensing on the back side of a localizer approach.

Re: Cheap GPS jammers are filling the world with navigation dead zones

#45

Post by nomel »

mschuster91 wrote: post #38
himata4113 wrote: post #33

Earlier quoted context omitted.

We have starlink I am sure they can figure something out.

Starlink lacks the high precision atomic clocks on board of the satellites, that is also why Starlink needs a GPS fix to bootstrap itself.

Maybe the starlink clocks could continuously calibrate from gps? Clock drift is usually a slow thing (like thermals). Their inter-satellite data links have all sorts of relative clocking info.

Re: Cheap GPS jammers are filling the world with navigation dead zones

#46

Post by abirch »

donohoe wrote: post #32

What I want is a tiny portable bluetooth jammer for those who insist everyone in public must be listening to their music. Sadly they are too clunky to haul around each day.

Unfortunately for me, when I hear music it's from the horrible audio of a cell phone speaker.

Re: Cheap GPS jammers are filling the world with navigation dead zones

#47

Post by nomel »

fangspire wrote: post #36

Starlink can be uses as GPS. Good luck jamming 20 thousand satellites.

That's near orders of magnitude more than reality. The only number that matters is the number of satellites that are in communication line of site. A satellite on the other side of the world doesn't help you.

Re: Cheap GPS jammers are filling the world with navigation dead zones

#48

Post by teeray »

mschuster91 wrote: post #40
teeray wrote: post #7

Earlier quoted context omitted.

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.

> 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] ht…

> 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

Re: Cheap GPS jammers are filling the world with navigation dead zones

#49

Post by leonidasrup »

mschuster91 wrote: post #40
teeray wrote: post #7

Earlier quoted context omitted.

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.

> 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] ht…

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

Re: Cheap GPS jammers are filling the world with navigation dead zones

#50

Post by _moof »

mschuster91 wrote: post #37
buildsjets wrote: post #10

Earlier quoted context omitted.

VOR is extremely short range and requires an extraordinary number of transmitters to provide any volume of coverage. Additionally it cannot provide coverage over oceanic areas. We USED TO have a nearly global long-range land based navigation system called LORAN, which only required one master station and a few remote stations to provide continent-scale coverage. But it was decommissioned in a cost savings move after…

> Additionally it cannot provide coverage over oceanic areas. It's really hard to jam oceanic areas though, you need a vessel capable of sustaining human life autonomously at least for days plus dealing with the high seas. Buoys could theoretically be used for that purpose, yes, but good luck getting them stationary enough. Maybe some of the secret services could pull off such a trick but at least no ordinary civilia…

> sustaining human life

Not really. Drone ships are very much a thing these days.

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