libnavigate is a portable C/C++ implementation of utilities for generating/parsing maritime navigation protocol (IEC 61162-1 2000-07 and NMEA 0183).
libnavigate is under LGPLv3. This means you can use the library with any open or closed source programs as a shared library. However, you cannot modify libnavigate and distribute it without supplying the source, or use it as a static library in closed source software.
See the COPYING and lgpl-3.0.txt files for the full license text.