Amazing isn't it, sub centimeter accuracy! And here we are cutting the edge with 0.03 ANP
I was with you up to the last sentence.. The sub-centimeter accuracy refers to what is essentially a differential GPS system, while the
0.03 ANP relates to an absolute GPS position.
Differential GPS is always going to be a lot more accurate, as lots of error mechanisms cancel out (e.g. variable ionospheric effects).