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Cheap GPS jammers are filling the world with navigation dead zones

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

#81

Post by numpad0 »

nomel wrote: post #45
mschuster91 wrote: post #38

Earlier quoted context omitted.

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.

IIUC, GPS picks one satellite and 3 more to establish time differences between the first one and the other 3. There's only one point in universe where the set of differences would match what was observed, given the broadcast orbital data of satellites, and that gives the location of the receiver. It's like you are provided radii and center coordinates of 3 circles on a paper that intersect at 1 point and you are to math that point.

So GPS-like systems need precise orbital data and coherent clock from each satellites, or otherwise the receiver cannot figure out those radii.

Presumably you can have each sats reflect a clock from the same master ground station but that's not how GPS is implemented currently.

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

#82

Post by numpad0 »

himata4113 wrote: post #67
mschuster91 wrote: post #38

Earlier quoted context omitted.

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

We have starlink I am sure we can figure it out. Like... launch a better GPS system with one rocket?

doesn't take sat swarms. what you need are some cash and bunch of educated and motivated smart people. that can be tricky sometimes

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

#83

Post by bigfatkitten »

stefan_ wrote: post #21

The systems jamming in Hormuz and Ukraine aren't exactly cheap and low powered, nor are those used by the US military in one of their many jamming exercises every year. Cheap GPS jammers fit in a cigarette lighter and are used by truckers who don't want their boss snooping on them, but they don't quite threaten aviation. That aside, you don't need to give up on GPS just yet. As expensive as airplanes are, there is no…

> Cheap GPS jammers fit in a cigarette lighter and are used by truckers who don't want their boss snooping on them, but they don't quite threaten aviation.

They absolutely do threaten air and maritime navigation, because those trucks drive in and near ports and airports.

https://insidegnss.com/fcc-fines-operator-of-gps-jammer-that...

https://ilwulocal94.org/news/2024/CSA%2001-24%20GPS%20Jammin...

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

#84

Post by malfist »

mike_d wrote: post #69
cjbgkagh wrote: post #68

Earlier quoted context omitted.

Probably be easier and more reliable to use star navigation with modern cameras, computers and atomic clocks. Especially for commercial aircraft flying above the weather.

Celestial navigation requires an accurate clock and an almanac that needs to be updated. It is completely impractical for non-military applications.

Does the almanac need updating? I regularly use plate solving with my telescope and I've never had to update it's stars database

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

#85

Post by sokoloff »

bb88 wrote: post #65
michaelt wrote: post #42

Earlier quoted context omitted.

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…

GPS jamming was being investigated by the NTSB as a possible reason for this air crash that killed 4 people near White Sands Missile Range. The plane reported GPS signal loss 5 minutes after the jamming started by WSMR. Three other planes in the area also reported GPS loss. https://www.stripes.com/theaters/us/2026-08-05/ntsb-medevac-...

I’d bet a lot of money that the NTSB will determine that the pilots’ failure to maintain clearance from terrain during a visual approach will be the primary cause with contributing factors of dark, moonless night and GPS jamming.

That one’s going to be on the flight crew, not the GPS jamming test.

HN discussion: https://news.ycombinator.com/item?id=49181099

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

#86

Post by civvv »

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…

Guess its back to the good ol' map, compass and stopwatch.

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

#87

Post by bb88 »

sokoloff wrote: post #85
bb88 wrote: post #65

Earlier quoted context omitted.

GPS jamming was being investigated by the NTSB as a possible reason for this air crash that killed 4 people near White Sands Missile Range. The plane reported GPS signal loss 5 minutes after the jamming started by WSMR. Three other planes in the area also reported GPS loss. https://www.stripes.com/theaters/us/2026-08-05/ntsb-medevac-...

I’d bet a lot of money that the NTSB will determine that the pilots’ failure to maintain clearance from terrain during a visual approach will be the primary cause with contributing factors of dark, moonless night and GPS jamming. That one’s going to be on the flight crew, not the GPS jamming test. HN discussion: https://news.ycombinator.com/item?id=49181099

I'm not going to argue that as it's always easy to blame dead people, but there's two different types of jamming.

One is to actually jam the signal IOW preventing reception. The other is to overpower the satellites' signals and replace them with your own. That defeats the doppler calculations of GPS needed for triangulation, and instead the receiver believes it's where the jammer wants it to be.

If the latter includes altitude information, then it's a huge problem.

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

#88

Post by raron »

mike_d wrote: post #69
cjbgkagh wrote: post #68

Earlier quoted context omitted.

Probably be easier and more reliable to use star navigation with modern cameras, computers and atomic clocks. Especially for commercial aircraft flying above the weather.

Celestial navigation requires an accurate clock and an almanac that needs to be updated. It is completely impractical for non-military applications.

Is that really that impractical?

With a quick calculation 50 ms time offset would mean about 20 meter difference. You can get that accuracy with NTP over residential internet and a better TCXO could hold that for a day. You could sync clocks and download the almanac at each airport. The almanac could be digitally signed and NTP has an option for authentication, too. That's about 10 USD of hardware (plus what you need for image capture and processing).

I'm pretty sure with dedicated hardware and better solutions you could get much better accuracy.

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

#89

Post by Terr_ »

1718627440 wrote: post #58
mlhpdx wrote: post #35

With all the man made EM emitters in the world, it seems like passively matching what can be “seen” to a database of known emitters (with signal profiles and locations) could be extremely accurate where people are (less helpful on the open ocean and remote wilderness). Similar to what’s already being done with Wi-Fi and Bluetooth but general purpose, perhaps?

I think that is already done by the two big smartphone OS vendors.

They record spots for all wireless access points too, unless you opt-out by naming them certain ways and the surveillance-capitalism company decides to honor it. (e.g. The _nomap suffix.)

I hope some future Wifi standard makes it much easier to anonymize or obscure persistent access points.

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

#90

Post by sokoloff »

bb88 wrote: post #87
sokoloff wrote: post #85

Earlier quoted context omitted.

I’d bet a lot of money that the NTSB will determine that the pilots’ failure to maintain clearance from terrain during a visual approach will be the primary cause with contributing factors of dark, moonless night and GPS jamming. That one’s going to be on the flight crew, not the GPS jamming test. HN discussion: https://news.ycombinator.com/item?id=49181099

I'm not going to argue that as it's always easy to blame dead people, but there's two different types of jamming. One is to actually jam the signal IOW preventing reception. The other is to overpower the satellites' signals and replace them with your own. That defeats the doppler calculations of GPS needed for triangulation, and instead the receiver believes it's where the jammer wants it to be. If the latter include…

I believe it’s been made public that this was a jamming test, not a spoofing test.
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