> 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...

First of all, starlink has been jammed in conflict zones.

Secondly, the number of satellites doesn’t really matter, the jamming happens at the end user level not at the satellite.

Finally, where are you getting that 20k number from? It’s not like there’s 20k starlink satellites in LOS to your station at all times. The earth will be obscuring many of those, they are below your feet on the other side of the planet.

Do they have atomic clocks on board?

I was under the impression that Starlink needs GPS for initial acquisition.

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.

They've removed the in-built PNT service

It's not rocket science to make a GPS jammer. GPS Spoofing is more complex and causes way more damage or chaos. I would seriously avoid touching this subject whatsoever this is the kind of thing that will have the FBI and FCC so far up your ass you will feel it in the back of your eyeballs. On the off chance the feds don't catch you and you cause a serious accident you will be charged with 1st degree murder of how many people were on the aircraft that crashed along with a litany of other federal offences meaning life without parole is basically a guarantee.

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The magnetic approach is very interesting. I can't imagine it would ever be reliable enough for a primary instrument since its susceptible to solar weather and certain regions with more geological activity.

Also see https://q-ctrl.com/ironstone-opal

I'm sorry, but a multi-kilogram (at a guess), five-figure-priced (at a conservative guess) device with kilometer-scale error (per their actual press release) is not a substitute for a GPS.

And you probably can't improve on many of those specs no matter how much "inventing" you do. There's just not that much information in magnetic fields, especially if you don't spend an infeasible amount of money on keeping maps up to date. You're probably jammable, too.

The same applies to the gravitational hacks, and the mapping issue applies even to visual navigation.

Those guesses, by the way, are because not only is AQNav's "data sheet" worthless fluff, but they seem to be allergic to letting anybody even see a picture of the product. Which makes me doubt that they actually have what a normal person would think of as a "product" to begin with.