1. The Modernization of GPS: Plans, New Capabilities and the Future Relationship to Galileo
2. Kaplan, E. D. and Hegarty, C. J. 2005. Understanding GPS: Principles and Applications. 2nd Edition. Artech House, Norwood, MA. 703 pages.
3. Precise Point Positioning Using Combined GPS and GLONASS Observations
4. Hofmann-Wellenhof, B., Lichtenegger, H., and Wasle, E. 2007. GNSS Global Navigation Satellite Systems: GPS, GLONASS, Galileo, and more. 1st Edition. Springer Wien, New York. 516 pages.