WAAS is nice but dual-band receivers provide similar accuracy levels without needing to see that satellite. Ublox quotes on their ZED-F9P datasheet 1.5m accuracy for GPS+GLONASS+Galileo+BeiDou, increasing to 1m accuracy if using space-based augmentation (WAAS, EGNOSS, MSAS, GAGAN). Even without a SBAS, if you can do RTK, you can get 0.01m accuracy. (The corrections from a nearby reference station are even better than what you can get from a satellite.)
RTK is probably more available than people think. My state offers a public network of continuously-operating reference stations; you can sign up for a free account and then do whatever RTK madness you desire. https://cors.dot.ny.gov/ if you happen to be in New York.
(I realize now that I really wanted to reply to the person complaining about not being in North America, but oh well, maybe they'll find this.)
But the state-run reference stations are generally too far away from you to get that sweet sweet 1cm accuracy...
It's amazing what you can do with consumer-priced gear these days. I set up a Sparkfun ZED-F9P breakout board as a fixed beacon on my roof, and then their "RTK Facet" as the rover to do precise measurements to create a map. I could have done the basic thing I needed to by hiring a surveyor or eyeballing things with a tape measure, but this is much more general.
The GNSS software world seems to be a mess though, ripe for a paradigm shift. For example, QGIS seems to be based on flat projections with transformations rather than 3d-native - from what I can tell, QGIS seems to consider the "degree" to be a unit of length measurement! This leads to ridiculous things like being able to accidentally measure a nonsensical "cartesian" distance between two points that differs from the actual distance by a factor dependent on latitude.
I've still got to tidy up my own pipeline that lets me do things like turn N (point, distance) samples into a single point. I would have thought that type of operation would be common, but thinking about how surveyors work I guess they're usually locating points optically, rather than trying to position a GPS receiver at the point to be measured.
GIS software is indeed messy, but not because the people writing it don't know what they're doing. You seem to be approaching things from a Cartesian perspective, but GIS almost always works in spherical coordinates because the earth is (approximately) a sphere. It makes a lot of common operations easier too.
Imagine you go on a road trip (along the surface of the earth). How far have you driven? In spherical coordinates, that's just changing two angles. In Cartesian coordinates, it's an ugly mess. Doesn't hurt that it's a lot easier to measure angles in surveying than distance.
However, certain GIS systems like QGIS and arcGIS are designed for making maps and have to display things in a 2D space. Thus, they have a projection mapping the spherical coordinates to Cartesian canvas coordinates and back again. This leads to unintuitive behavior, but it's mathematically hard to do better.
Now, the user interfaces and the terminology and the subtly disastrous inconsistencies between different data sources? Hot flaming garbage, all of it. These aren't problems with the underlying data models though.
> You seem to be approaching things from a Cartesian perspective, but GIS almost always works in spherical coordinates because the earth is (approximately) a sphere
Actually no, I'm complaining about the exact opposite. I want to be working in spherical native coordinates, but QGIS seems to treat "degrees" as just another fixed unit of length measurement rather than an angular measurement!
For example I had the measurement projection set to "cartesian", which I would have expected to either give me the linear distance from (X,Y,Z) to (X,Y,Z), or the linear distance between (Lat,Lon) on an approximation of the earth's surface (either sphere or ellipsoid). Instead, it was treating (Lat, Lon) as if they were (X,Y) coordinates on a flat map and doing Pythagorean theorem on the angular measurements, resulting in the longitudinal distance being off by a factor of cos(latitude) !
I can see no paradigm in which such a result would ever be desired, apart from QGIS fundamentally working in terms of linearized projections, with WGS84/spherical coordinates being added on as an afterthought.
Yeah the software is ... interesting. I'm actually less than a mile away from a reference station, but don't get 1cm accuracy because I don't have a much of a sky view from my apartment's window. (But I'm moving soon and have a great sky view. And am closer to the reference station!)
RTK is probably more available than people think. My state offers a public network of continuously-operating reference stations; you can sign up for a free account and then do whatever RTK madness you desire. https://cors.dot.ny.gov/ if you happen to be in New York.
(I realize now that I really wanted to reply to the person complaining about not being in North America, but oh well, maybe they'll find this.)