Pursuant to a congressional request, GAO reviewed the development of differential global positioning systems (DGPS), focusing on: (1) the extent to which federal agencies have been developing joint systems or sharing equipment; and (2) additional steps needed to enhance joint development or sharing of DGPS equipment, facilities, and information.

GAO found that: (1) between 1988 and 1993, few agencies developed joint DGPS systems or shared DGPS equipment because they were exploring different applications and there was no interagency coordinating mechanism; (2) single-agency systems developed for mapping, surveying, and related activities could not share information because of incompatible equipment and data formats and differing agency operating procedures; (3) agencies had few incentives to share DGPS information or develop joint systems; (4) in 1993, the U.S. Coast Guard and the Federal Aviation Administration modified their DGPS to make them easier for other agencies to use; (5) a Department of Defense and Department of Transportation task force, formed to study DGPS issues, concluded that the ad hoc approach to DGPS development would likely result in unnecessary duplication; (6) the continuing rapid increase in DGPS applications increases the need for effective governmentwide coordination; and (7) the government is addressing technical coordination issues, but it is doubtful whether the coordinating structure will be adequate to ensure joint DGPS development and use.