Can NEXRAD and industry share the S-band? Exploring the impact of RF interference on the WSR-88D estimators

1. Abstract Expanding use of wireless technology has prompted a dialogue concerning the reallocation of several bands within the RF spectrum. Included in the discussion is the 2.7 to 3.0 GHz band, where many meteorological and aircraft surveillance radars reside. Reducing the width of the allotted band or opening the band to additional transmitters will undoubtedly generate more instances of unwanted RF interference between radars. In an effort to quantify the potential impact, a simulation-based study was commissioned to explore the extent of the corruption through statistical means. RF interference can appear in three primary forms: pulsed, continuous wave, and noise-like. The scope of the study is limited to the effects of interference on Level-II base products, and performance is judged in terms of the NEXRAD Technical Requirements from the WSR-88D System Specification (ROC, 2008). Time series simulations are utilized to model the effects of interference on the estimation of meteorological variables. With the advent of the dual-polarization upgrade of the NEXRAD system, we consider all six of the meteorological variables that are sent as Level-II products: reflectivity (Z), Doppler velocity (v), spectrum width ( v), differential reflectivity (ZDR), differential phase ( DP), and correlation coefficient ( hv). Previous technical reports such as ITU-R M.1464, ITU-R M.1849, NTIA TR-06-444, and NTIA TR-13-490 were reviewed to ensure that the study is consistent with established approaches for quantifying the impacts of interference on NEXRAD radars. A more detailed account of this study is available in a full technical report (Curtis and Isom, 2014). In the next section, we summarize the types of interference that are examined in the study, explore the best way to apply the NEXRAD Technical Requirements to quantify the detrimental effects of interference, and define the scanning strategies that are used in the simulations. Subsequent sections explore the simulation methodology and results, and highlight some future considerations for interference on WSR-88D radars.