In 1973, the U.S. Department of Defense (DoD) began the development of the Navstar Global Positioning System (GPS) and embarked on a journey that would take radio navigation and positioning to what were then unimagined levels of performance. From its inception, GPS was viewed as a revolutionary technology that would enhance the positioning capability of U.S. and allied military forces throughout the world. The DoD has continued to upgrade and improve all of the components of the system to keep pace with technology advances and the requirements of an ever-expanding user community. Today, GPS has evolved far beyond the vision of its original designers, and satellite navigation is now widely recognized as a worldwide information resource for both military and civilian users. The GPS user community includes an increasing number of civil, scientific, and commercial applications, ranging from precision farming to pinpointing disruptions in electric power distribution networks. However this dual military and civil aspect of GPS has posed significant challenges for U.S. Government and DoD policy makers. Since the inception of GPS, the DoD has been confronted with the need to balance a wide range of different and sometimes competing national security civil, foreign policy, commercial, and scientific interests. The challenge has been to exploit the full civil utility of the system without jeopardizing national security interests in the process. This challenge will became even more formidable for military leaders as U.S, and allied forces become increasingly reliant on GPS for all types of military operations, and as the applications of the worldwide civil user community continue to expand.
