GPS
GPS calculates the position of a receiver by triangulation, using information provided by satellites. The minimum information needed to calculate the position is 4, but more measurements allows to reduce the error of the measurements and provides a more precise position.
Another technique used to reduce the error is DGPS (Differential GPS), which uses two receivers where one stays stationary.
A deeper explanation on GPS can be found on this website.
GPS is only suitable in robotics for outdoor robots.
Notes References
20210514183815 INDEX - Robotics
20210523205908 Robotics Complex Sensors - Basics
References
GPS explanation - https://ciechanow.ski/gps/
(Murphy 2000)
Murphy, Robin. 2000. Introduction to AI Robotics. Intelligent Robotics and Autonomous Agents. Cambridge, Mass: MIT Press.