Basically, companies who use GPS for measurements or what have you, can pay money and get access to improved accuracy.
As the US found, in practice such services are largely useless, they sound cool, but in practice COTS (Commercial Off The Shelf) dominates. The $50 device you see on Amazon has better features than the $500 military product your supplier offers. When you ask the Amazon supplier can sell you 1-1000, with 48 hour delivery but your military supplier quotes 6-12 months with batches of 500.
Can the enemy jam your $50 Amazon special? Maybe. But in a hot war zone, unlike for an annoying neighbour, jamming isn't necessarily an effective strategy because it involves transmitting radio signals, which makes you a target.
https://www.euronews.com/my-europe/2022/06/07/like-nato-the-...
1m vs 1cm is not a big deal for a rideshare driver. On the other hand, if two bridge spans meet in the middle and are 1m misaligned, that’s a huge problem.
https://www.takeoffpros.com/2019/07/31/gps-surveying-explain...