It's a bad idea what it end up starting a cycle where every big application uses their own DNS. Some of them might not wven do it right

That will defeat the whole purpose. Remember, we are not writing code here but trying to optimize code based on what code that machine produced

> Eu will know where were you when you requested something

You don't request a positioning signal, they are broadcast by the satellites and nothing is sent back by the receivers. Some devices (like smartphones) may send their GPS discovered position over the Internet, where encryption may be used, but this is not what is being referred to.

Encryption allows you to restrict access, or provided tiered access to signals of varying accuracy. You can also use cryptography in order to prevent spoofing.

> You can also use cryptography in order to prevent spoofing.

I think that's probably the biggest selling point given how many important infrastructures rely heavily on GPS these days.

I agree, although I'm not sure whether it's ever been implemented for public use.

You get anti-spoofing naturally if you're just using secret symmetric encryption (if your adversary doesn't know the key, they can't generate a valid signal to trick you with). To prevent spoofing against the public, you'd need to make use of public-key cryptography.

Yes, encrypted GPS makes sense. You can broadcast additional information that can be used for more precision only on encrypted channels, and have people pay for the decryption keys. (That's part of how the better-quality GPS for US military works)

Another way is selling online access to better-quality correction data.

Neither necessarily involves telling anyone where you are.

The encrypted channel just involves knowing a secret "key". This is in principle viable for high value military work, and you're right that Galileo has reserved such a channel.

In practice the Americans learned that COTS dominates for electronics. You can buy 100 of the special military product with the secret key, delivery in 18 months or for the same price you can have 5000 of the generic civilian product, 10 days lead time.

So these secret extra channels are of dubious value. But they're cheap to implement so they remain something new GPS style systems have.

In theory keeping the key secret defends against a sophisticated adversary spoofing your signal. But there's an obvious trade, if you only make ten units you can probably ensure the adversary doesn't capture one, but it's not very useful. If you make a million units that's initially more useful but your adversary will definitely get the key.

Even the US military doesn't use the encryption channels much anymore. Turns out that differential GPS is more accurate and you don't even need the encryption channel to do it. We already know the next message the GPS will send with high accuracy, the important part is detecting exactly when the first bit arrives at the antenna you everything you need from that.

If you want to get more accurate you don't use the encrypted channel you put a GPS in a fixed location on earth and have it send corrections to you. (called RTK)

Edit: Note that I have no information on what the US military uses their classified channel for. It is unlikely they get any accuracy information from it anymore given what civilian GPS systems have figured out.