References on the basics of GPS theory and application
Blewitt, G. (2007), GPS and Space Based Geodetic Methods, chapter in Treatise on Geophysics, Vol. 3., pp. 351-390, Ed. Thomas Herring, Ed.-in-chief Gerald Schubert, Academic Press, Oxford, UK, ISBN: 0-444-51928-9. (PDF)
Dixon, T., The Global Positioning System, Review of Geophysics, 1991.
Segall, P. and J.L. Davis, GPS applications for geodynamics and earthquake studies, Annual Reviews of Earth and Planetary Science, 25, 301-36, 1997.
Strang, G. and K. Borre "Linear Algebra, Geodesy, and GPS", Wellesley-Cambridge Press, 1997. (available in print or also on Google books),