Technically all RF communications are "public." You have to use encryption if you want security.
replyWould point to point laser seem like it's RF and not readily snooped without detection?
replyUnless you are in a vacuum, a laser that can reach a useful distance can be observed due to atmospheric scattering.
replytrue!
replyYeah GPS is not the people's airwaves it is operated by the US Space Force, I suggest you read up on your history.
replyOK, I have to further narrow down my statement then: a publicly readable medium (or one-way channel).
replyI didn't want to imply that regular people could simply inject data into what's emitted by GPS satellites.
Sorry if that wasn't clear, but I am aware that GPS is operated by the US military.