gps can be used to host a GPS server, or to determine a position using trilateration.
Type "help gpsapi" for help using GPS functions in lua programs.

ex:
"gps locate" will connect to nearby GPS servers, and try to determine the position of the computer or turtle.
"gps host" will try to determine the position, and host a GPS server if successful.
"gps host 10 20 30" will host a GPS server, using the manually entered position 10,20,30. 

Take care when manually entering host positions. If the positions entered into multiple GPS hosts
are not consistent, the results of locate calls will be incorrect.