Open Source C GPS Software for Windows

Viking is a free/open source program to manage GPS data. You can import, plot and create tracks, routes and waypoints, show OSM, Bing Aerial and other maps, geotag images, create routes using OSRM, see real-time GPS position (not in Windows), make maps using Mapnik (not in Windows), control items, etc. It is written in mostly in C (with some C++) & the GTK+3 toolkit. Viking is currently dual managed - with a corresponding Github presence at: https://github.com/viking-gps/viking Where you may find it easier to view the code and raise issues there too.

MerakoGPS is a set of software for Merako-series board aiming at GPS receiver development. MerakoGPS runs on a flexible Merako-series hardware board which uses a CycloneIII FPGA to accomplish the correlator function. see http://www.hyrising.com.