the really serious guys use GPS based equipment, and its serious stuff, being able to center up on a 1/64 inch brad tacked into the asphalt.
[that 50,000$ ufo on a tripod by the highway, dont try to steal one, man do they ever know exactly where they are]
yeah i like team yellow too :) the beam spread is what you want to check out if your serious about > 100 ft distance
^ this is a very commercial website, but example of higher end equipment and technique
How do you calibrate the GPS
there is a sattelite network, and a terrestrial reference station infra
Yeah but how do we know there distances accurately
usually laser ranging is used to establish a baseline, rather than using a theodolite and chain like OG surveyors.
the rest is trigonometry, withe the GPSS defining points relative to the baseline.
https://www.gps.gov/trilateration
https://apps.dtic.mil/sti/html/tr/ADA165932/index.html
https://app.studyraid.com/en/read/15241/528230/determining-d...