Aerospace Figures in Decision to Add Second GPS Civil Signal

EL SEGUNDO, Calif. (4/13/98) -- The Aerospace Corporation played a key role in the decision by the government, which was announced by Vice President Al Gore March 30, to add a second Global Positioning Signal (GPS) for civilian users.

According to John E. Clark, systems director of the System Development and Engineering organization in The Aerospace Corporation's GPS Directorate, Aerospace:

• was an early proponent of the benefits of adding a second frequency for civilian use, of identifying the technical benefits to civilian users of the new frequency, and of identifying the shortcomings of the existing single-frequency architecture
• was one of the technical leads to the Air Force and the Federal Aviation Administration in identifying alternatives for selecting the frequency, and for identifying pros and cons of new allocations versus reuse of the existing spectrum for new military and civil signals
• proposed accommodating the new civil and military signals by creative reuse of the current GPS signal bandwidth rather than by seeking new frequency allocations elsewhere in a crowded spectrum

In conjunction with the phaseout of selective availability of accurate signals for the military by 2006, the new signal will greatly improve the overall accuracy of the system for the average user. In the past, for security reasons, the system has been considerably less accurate for non-military users.

The vice president said the decision "demonstrates that we can successfully balance the needs of civilian users with the demands of national security."

According to a statement from his office, the new signal "represents a strong commitment by the United States to civil GPS users worldwide and is a major step in the evolution of GPS as a global information utility. Much like the Internet, GPS is becoming increasingly indispensable for navigation, positioning, and timing by users around the world" and "has become an engine of economic growth and efficiency as businesses and consumers continue to develop new and creative applications of this technology," the statement said.

The new signal has been recommended by a number of panels, the most recent of which was the White House Commission on Aviation Safety and Security chaired by the vice president.

According to the vice president's office, the announcement on March 30 "fulfills a pledge made last March by the departments of Defense and Transportation to reach a decision on a second civil frequency within a year."

The departments co-chair an Interagency GPS Executive Board created by President Bill Clinton in 1996 to manage GPS. The board selected the 1227.6 MHZ band (currently known as the L2 signal) for the addition of the new civil capability. A third civil signal is also to be added with a decision on the frequency to be made in August.

Aerospace was intimately involved in the conception and development of GPS and is responsible to the Air Force for technical enhancements to the system and to its maintenance. The company also provides technical oversight, systems integration support, and launch readiness verification for orbit-insertion operations.