It's probably safe to conclude that they don't, but you don't need COMSEC crypto keys to achieve "military-grade" accuracy down to 10cm either, i.e. differential GPS[1].
Yea I was on a project where a professor lent us a Trimble GPS (I think they ran $2k ~ $4k at the time). It had a backpack, synced up with a tower at the local airport and gave us information down to a couple of centimeters.
[1] https://www.effective-solutions.co.uk/beacons.html