Civil and mining engineers have been making use of centimeter-accurate GNSS configurations for years now. The equipment necessary costs a few thousand dollars, more if you need even more precision. Most major civil and mining engineering projects use self-guided earth-moving equipment, not feasible without this technology.

The problem for homeowners is that surveys aren't enough. The vast majority of land titles are not registered in precise coordinates; they're registered in terms of landmarks, benchmarks, and so forth. This is changing at a glacial pace, but for now, the tech isn't the problem.