not propagated directly from transmitter to receiver and then to determine the time of arrival of the direct path signal as accurately as possible. A propagation measurement effort in support of this objective will develop a database of measured signals that have propagated outdoors over ranges that can be supported by the allowed UWB transmitter power, as regulated by the Federal Communications Commission (FCC). This database will also include propagation conditions, information on direct path obstructions, and so forth, and will have general applicability to communications designs as well as ranging algorithm development.

The committee believes that the work on UWB ranging represents achievable technology and hardly qualifies as basic research. It entails buying some wideband radios and creating pulses short enough that multipath problems can be resolved. This is very similar to the analysis and experimentation done by telephone companies before they install a new tower, especially in an urban environment. If the intent of this work is to specifically address urban environments, it should be recognized that the Defense Advanced Research Projects Agency (DARPA) and other agencies have already addressed data collection, modeling, and simulation of ultra-wideband communications in such environments. Moreover, many high-fidelity models exist for wideband communications and signal propagation. And finally, based on the small amount of information provided, the committee cannot help but wonder what this project will contribute and how it relates to the existing legacy.

The committee recommends that this project should be considered for the core 6.2 discovery technology program and the funds freed up for more fundamental research. If the project is funded as a 6.2 effort, then care should be taken to identify what measurements will be made, whether these measurements have already been made by other agencies, and what models will be developed.