The Federal Highway Administration, in association with the US Coast Guard, National Geodetic Survey, and several other Federal agencies, is implementing a High Accuracy Nationwide Differential Global Positioning System (HA-NDGPS) capability for test purposes at the Hagerstown, MD, Nationwide Differential Global Positioning System (NDGPS) facility.

The service is expected to be available from April 2002 until April 2003. Preliminary results indicate that the HANDGPS will enable 3D positioning at an accuracy of 20 cm (95% confidence level) for points located within 200 miles of a single reference station.

A Request for Testers of a High Accuracy Differential GPS (HA-NDGPS) System was posted on the Federal Business Opportunities website on January 17, 2002 ( Up to 4 HANDGPS receivers will be loaned to organizations (at no cost to the organization, with no remuneration from the government) to perform tests, for up to a two-month time period during the test period. As a condition of loan, FHWA will require that any data collected be provided to FHWA (with unrestricted data rights) so that further analysis/reporting/documenting of this technique can be accomplished.

Electronic proposals from parties interested in testing this technology are being accepted. For more information, see the January 17, 2002 posting. To aid potential testers and users in understanding the techniques used for this service, a workshop is planned for April 16, 2002 at the National Oceanic and Atmospheric Administration Auditorium. The purpose of this workshop is to provide industry, academia, and other government agencies with technical details of the High Accuracy NDGPS program. Technical experts will be available to answer technical questions on this service.

DATE/TIME: April 16, 2002, 1:30 PM to 5:00 PM local time
LOCATION: U.S. Department of Commerce, NOAA Silver Spring Metro Campus Auditorium, 1301 East-West Highway, Silver Spring, Maryland
TRANSPORTATION INFO: Parking is available. Public Transportation is available via the Washington Metrorail System's Red Line. For a map of the vicinity and parking garages in the area, please visit:

Technical questions should be addressed to Mr. James Arnold, FHWA, at 202/493-3265, or by email to