1. A portion of this paper has been extracted from the first chapter (by B. W. Parkinson) of the forthcoming AIAA book Theory and Applications of GPS B. Parkinson J. Spilker P. Axelrad P. Enge
2. Space Applications Branch Ranging and Velocity Experimental Equipment 18 April 1968
3. Bartholomew , C. A. Quartz Crystal Oscillator Development for Timation 25 October 1972