No they don't. They need fairly coarse tracking (A few feet or so.) for geolocation as that is only to make sure you end up covering the whole field.

Now for individual weeds you need precise aiming but that's only from a few feet away at max.

The overall geo location boils down to being able to track a row as you go down it and then go to the next row at the other end. The lasers don't care about the geo location at all.

RTK GPS has +/- 3cm Lat/long precision. That gets you very close, and then with a confirming camera, you could aim and fire.

Unless you have a precise map of all the weed locations, precise location in absolute world coordinates doesn't seem too important. You'd need fairly precise and accurate relative positioning from tank to drone and drone to weed, though. Drone to weed could be done via camera (you need to detect the weed anyway), but tank to drone would likely be a difficult engineering problem.

A flying drone seems like the wrong way to solve the problem, though. For a drone close enough to the ground to reliably detect weeds, you'd likely need a multi-rotor, a slow flying fixed wing aircraft, or a blimp. A multirotor has a huge energy penalty, and a fixed wing aircraft or blimp loses the practical gains vs. just using a tractor of some sort.