ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / Due to vehicle dynamics in mobile systems, GPS signal reception may be blocked by the body of the vehicle. This paper discusses various studies made on some vehicles such as the Space Shuttle, various aircraft, and analyzes the implementation of dual GPS antenna systems. Constructive and destructive interference characteristics of signal combining are considered. The author suggests an approach which uses a delay line on one of the antennas while analyzing the front end C/N0 needed for L1 GPS reception. An embedded Excel spreadsheet provides a front-end Noise Figure (NF) calculation tool based on user selected parameters.