Farming is not the first technology, but is the one that put mankind on a development trajectory with a speed that had never existed before. To know where you are on the planet has been a challenge that got solved relatively late. The cockpit of 747 still hat a hole in its cockpit so that the navigator could shoot the stars to get a location.
Right now there are a couple of systems:
- Navstar, USA, 1993
- Glonass, Russia, 2005
- Galileo, EU, 2016
- NavIC, India, 2018, regional
- Michibki, Japan, 2018, regional
- BeiDou, China, 2020
Precision is anywhere from millimeters (claims by China), to cm (EU, if it finally works and encrypted) to meters (everybody).
Combining GPS with farming makes total sense. Interesting that the savings can be so substantial high once the equipment gets guided by math, not a farmers.