This reference and handbook describes the functional software library of the Global Positioning System (GPS/Galileo). It is the original software source-code of many functions, models, algorithms and tools described in the textbook "GPS - Theory, Algorithms and Applications" written by the same author published by Springer. The software functions are parts of the KSGsoft and MFGsoft programs developed by the author at the GFZ in Potsdam. All the...