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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 it was determined that it could be replaced by GPS. It worked perfectly fine until it was decommissioned in 2010, not that long ago.

In the '90s I used to fly light aircraft back and forth between Seattle and Alaska. You were frequently out of range of any VOR transmitters, but that LORAN always worked. NDBs? That didn't work so great for Ron Brown.

https://en.wikipedia.org/wiki/Loran-C

maybe we need to update those giant concrete arrows on the ground...

https://en.wikipedia.org/wiki/Transcontinental_Airway_System

and have giant concrete QR codes

Most pre-GPS navigation systems have shorter baselines than GPS and therefore accuracy is much worse, on top of generally being more complicated

All VORs provide a radial that you’re on. Not all provide a distance to the station. VOR/DME or VORTACs provide both. Plain VORs do not.

As more and more are decommissioned, the percentage that support distance-measuring goes up, as the ones being decommissioned are more likely to be the less-useful ones, which are less likely to have supported DME in the first place. So most remaining ones support both, but it’s not assured without checking.

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?

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

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.

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.

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

https://stfu.pankajtanwar.in/

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

Are they? You can make one pretty easily and sew it into your backpack for added camouflage. I heard.

If I am not mistaken, this type of jammer can severily affect people with pacemakers. But, as a Brazilian citizen, I can understand the feeling of being forced to listen other's people music.

how i even make a clunky one ? need one for a neighbor in 3rd world country with lowest civic sense.

i tried that esp32 that uses nRF24 but it doesnt seem to jam all the time. i heard about hackrf one dont know if its can properly do that.

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

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.

See UK and France:

* https://insidegnss.com/uk-and-france-renew-ties-resilient-pn...

LORAN can be jammed.

Better use a software defined radio like hackrf or a more dedicated gps thingy, esp32 with gps addon and some machine learning? (‘Some’ doing a lot of heavy lifting here)

I feel like gps nav software should start considering the jamming and spoofing cases as real conditions they will encounter that should throw up an INOP warning.

It wouldn't take much smarts for it to consider the type of vessel it's in and the max and current speeds. If the calculated position of a 10 knot vessel suddenly jumps 100 km away in seconds, that sure seems like a spoof. And if you had 10 satellites locked and then you have none, that sure seems like jamming, or you're in a tunnel; INOP either way.

> 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...

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.

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.