aprs

RadioLib

+10

Universal wireless communication library for embedded devices

SoftRF

+1

:airplane: Multi-functional, compatible DIY general aviation proximity awareness system

direwolf

+1

Dire Wolf is a software "soundcard" AX.25 packet modem/TNC and APRS encoder/decoder. It can be used stand-alone to observe APRS traffic, as a tracker, digipeater, APRStt gateway, or Internet Gateway (IGate). For more information, look at the bottom 1/4 of this page and in https://github.com/wb2osz/direwolf/blob/dev/doc/README.md