Assessing Ultra Wide Band (UWB) Interference to GPS Receivers

B. M. Titus, P.A. Dafesh, R. Wong, K. P. Maine, T. A. Stansell Jr.

Abstract:	In February 2002 the Federal Communication Commission approved a Report and Order (R&O) for the use of Ultra Wide Band (UWB) devices in commercial and federal bands [1]. This R&O allows UWB emissions at specified power levels within "restricted" radio frequency bands, including the bands used by GPS. The levels were designed to protect the operation of GPS and other federal government radio frequency systems. Analysis conducted by the GPS Joint Program Office and The Aerospace Corporation, and testing accomplished by Stanford University (under the sponsorship of the DOT), and testing conducted by the National Information and Telecommunication Agency (NTIA), indicate the potential for UWB transmissions to interfere with the GPS signal. GPS receivers are increasingly becoming an integral part of many positioning, navigation, timing, and telecommunications systems that are depended upon for numerous public safety, national security, and safety-of- life operations. Although power levels were specified in the R&O that were perceived to adequately protect GPS operation in the presence of a single UWB device, it is still unclear that GPS operations will be protected for all time, and in all situations as the number of consumer UWB devices in operation increases. This is especially true for current and future civil and military uses of GPS within "stressed" environments such as under heavy foliage, indoors or in urban canyons. The impact of UWB devices emitting at the GPS L-band frequencies is expected to raise the effective noise floor of any GPS receiver that is near a UWB device. GPS signals are received at very low power levels and receivers must cover a wide bandwidth to enable high accuracy ranging. Based on analysis and measurements from commercial GPS receivers, this paper discusses the adequacy of the current FCC limits imposed on various categories of UWB devices with respect to protection of current and future civilian and military use of GPS. It recommends no relaxation of current UWB emission levels permitted in GPS frequencies.
Published in:	Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002) September 24 - 27, 2002 Oregon Convention Center Portland, OR
Pages:	1251 - 1259
Cite this article:	Titus, B. M., Dafesh, P.A., Wong, R., Maine, K. P., Stansell, T. A., Jr., "Assessing Ultra Wide Band (UWB) Interference to GPS Receivers," Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002), Portland, OR, September 2002, pp. 1251-1259.
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