GPS
References and Acknowledgments
Hurn, Jeff. GPS: A Guide to the Next Utility.Trimble Navigation Systems, 1989.
Sobel, Dava. The Illustrated Longitude. New York: Walter Company, 1998.
(2000). The Royal Observatory Greenwich. Royal Observatory Greenwich, London. [Online]. Availible: http://www.rog.nmm.ac.uk/index.html. [2000, April 13].
Dana, Peter, H. (1999) Global Positioning System Overview. The Geographer's Craft Project, Department of Geography, University of Texas at Austin. [Online].
Availible: http://www.utexas.edu/depts/grg/gcraft/notes/gps/gps.html. [2000, April 13].
(2000). GPS Primer. The Areospace Corporation. [Online].
Availible: http://www.aero.org/publications/GPSPRIMER. [2000, April 13].
(2000). Trimble. The Trimble Navigation Limited. [Online].
Availible: http://www.trimble.com/maps/index.htm. [2000, April 11].
(2000). Garmin. The Garmin Corporation. [Online].
Availible: http://www.garmin.com/. [2000, April 11].
Dunbar, Brian. (2000). Nasa Home Page. NASA. [Online].
Availible: http://www.nasa.gov/. [2000, April 11].
(1998). Precision Farming. Advanstar Communications, Inc. [Online].
Availible: http://www.precisionfarming.com/. [2000, April 13].