[knorker]

Another question for knowledgeable people here:

Can I not just run two GNSS receivers 10 meters apart (on a ship), and if they report as having the same position, then I know someone is spoofing?

It should be really hard to beamform the spoofing to spoof two different locations, at least from a distance because of the precise angles needed.

Yes, this assumes that my real GNSS signal is good enough that they normally are 10M apart.

[jaywalk]

The article addresses that scenario, and confirms that using multiple receivers would allow you to reliably detect spoofing. They'd report the same location but a slightly different time.

[knorker]

Yes, but such countermeasures (like the ones mentioned in the article) are about one receiver doing fancy RF tricks. What I'm proposing is something entirely done by two cheap and existing receivers today, by the end user.

[PaulHoule]

There's a patent on that one.