Assessment of Compatibility between Ultrawideband (UWB) Systems and Global Positioning System (GPS) Receivers

David S. Anderson, Edward F. Drocella Jr., Steven K. Jones, and Mark A. Settle

Abstract: The study described in this report was undertaken by the National Telecommunications and Information Administration (NTIA) in response to a Federal Communications Commission (FCC) Notice of Proposed Rule Making (NPRM) concerning the operation of a new class of spectrumdependent devices, designated as ultrawideband (UWB) devices under the FCC’s rules and regulations in Part 15 of Title 47 of the Code of Federal Regulations (CFR). This NPRM raises a number of questions and concerns regarding the electromagnetic compatibility (EMC) of the proposed UWB transmitting devices to those spectrum-dependent systems currently in operation. The NTIA, as the Executive Branch agency principally responsible for developing and articulating domestic and international telecommunications policy affecting Federal Government spectrum users, is particularly interested in the potential for interference to telecommunications infrastructure utilizing Federal Government spectrum for critical and/or safety-of-life functions, many of which operate in spectrum designated as the “restricted frequency bands.” These frequency bands have been designated as restricted because the systems operating in them provide critical safety functions. Before NTIA can agree to emissions from UWB devices in restricted frequency bands used by critical Federal Government radiocommunication systems, it must ensure that there is no potential interference introduced from their proposed operations. The Global Positioning System (GPS) is an example of a critical radionavigation system that operates in several of the restricted frequency bands.

The primary objective of this study is to define maximum allowable ultrawideband (UWB) equivalent isotropically radiated power (EIRP) levels that can be tolerated by GPS receivers, when used within various operational applications, without causing degradation to GPS operations. These EIRP levels are then compared to the emission levels derived from the limits specified for intentional radiators in C.F.R., Title 47, Part 15.209 to assess the applicability of the Part 15 limits to UWB devices.

Keywords: interference; RF; global positioning system (GPS); ultrawideband; UWB; equivalent isotropically radiated power; intentional radiators; radio frequency; effective isotropic radiated power (EIRP)

(ntiasp_01_45.pdf)

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

For questions or information on this or any other NTIA scientific publication, contact the ITS Publications Office at ITSinfo@ntia.gov or 303-497-3572.

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