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 def

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://www.gps.gov/trilateration https://apps.dtic.mil/sti/html/tr/ADA165932/index.html https://apps.dtic.mil/sti/html/tr/ADA165932/index.html https://app.studyraid.com/en/read/15241/528230/determining-distances-with-triangulation https://app.studyraid.com/en/read/15241/528230/determining-d...