Test Plan for Determining Potential for Interference From Ultra-wideband Devices (UWB) to Global Positioning System (GPS) Receivers; Response to Comment

AGENCY:

Office of the Secretary, Department of Transportation.

ACTION:

Response to comment.

SUMMARY:

DOT announced a test program to begin to acquire data on the potential for interference to GPS systems from UWB signals, and sought comment thereon. Only one comment was received, which warrants additional explanation of, but no changes to, the test program.

FOR FURTHER INFORMATION CONTACT:

Sally L. Frodge, Radionavigation and Positioning , P-7, (202) 366-4894

SUPPLEMENTARY INFORMATION:

The Department of Transportation (DOT) became aware last year of the potential for interference to the Global Positioning System (GPS) and other communications, navigation, and surveillance systems, including actively used aviation systems, from ultra-wideband (UWB) signals. Due to the lack of technical data on interference available at that time, DOT decided to initiate a limited testing program to begin to explore the interference potential of UWB to GPS. Working with the National Telecommunications and Information Administration, the Federal Aviation Administration, the Interdepartment Radio Advisory Committee, RTCA, Inc., and others, a test plan was devised to develop data in a technically sound and controlled manner. The Department contracted with Stanford University to perform the tests. In addition, because of the potential for wide public and industry interest in this matter, the Department distributed the test plan broadly and formally solicited comment on the plan through a notice in the Federal Register. 65 FR 38874 (June 22, 2000). Only one party submitted comments in response to this notice—Time Domain Corporation (TDC).

TDC criticized the test plan and concluded that it would not produce valid data about the potential for interference from UWB signals. DOT appreciates the TDC comments. Although DOT disagrees with TDC's assessment of the efficacy of the test plan, it is clear that additional clarification of certain points in the plan description and an explanation of the rationale for the plan's basic approach are warranted. DOT remains confident that the test plan is methodologically sound and will develop data that will help support a determination about whether and to what extent UWB emissions will interfere with GPS applications.

DOT's complete response will be sent to TDC, and to other interested parties upon request. DOT will provide all data and analyses available from the test program to the FCC by October 30, 2000, the filing date for test results in FCC ET Docket No. OST-98-153. The test program will be incomplete at that time and further results will continue to be developed into the first quarter of 2001.