The Global Positioning System (GPS) was originally designed primarily to provide highly accurate radionavigation capability to U.S. military forces, while also providing an unencrypted signal of degraded accuracy to civilian users. As the system developed, civil usage expanded rapidly and the number of civilian users now greatly exceeds the number of military users. The timing, velocity, and positioning information provided by GPS is being used for a growing number of new, innovative applications that could not have been foreseen by the original system designers. Because of its widespread use by both the military and civilians, GPS has truly emerged as a dual-use system.

Recognizing that the continued existence of GPS as a dual-use system clearly requires some trade-offs between civilian utility and national security, Congress requested a joint study by the National Academy of Sciences and the National Academy of Public Administration (NAPA) on the Department of Defense's Global Positioning System (GPS). The National Academy of Sciences was asked to recommend technical improvements and augmentations that could enhance military, civilian, and commercial use of the system. The National Academy of Public Administration was asked to address GPS management and funding issues, including commercialization, governance, and international participation. To conduct its part of the study, the National Academy of Sciences established an expert committee through the National Research Council (NRC), the operating arm of the National Academy of Sciences and the National Academy of Engineering.

This report provides the results of the technical portion of the study conducted by the National Research Council's Committee on the Future of the Global Positioning System. Portions of this report (for example, Chapters 3, 4, and some of the appendices) also are included in the joint NRC/NAPA report, The Global Positioning System — Charting the Future, which contains the complete results of the NAPA portion of the study.

In examining future enhancements to the GPS system, the NRC committee endeavored to balance the features that would enhance civil applications against the clear requirement to maintain the military integrity of the system. The recommendations in the report were intended to meet this criterion.

Laurence J. Adams, Chair
Committee on the Future of the Global Positioning System