מקורות, ולקריאה נוספת:

Global Positioning System History
https://www.nasa.gov/directorates/heo/scan/communications/policy/GPS.html

Korean Air Lines Flight 007
https://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007

Trilateration vs Triangulation
http://gisgeography.com/trilateration-triangulation-gps/