Spectrum Issues Faced by Active Remote Sensing: Radio frequency interference and operational restrictions Technical Committees

The scientific users of radio frequencies must contend with the fact that the spectrum is becoming increasingly crowded, which is in large measure due to the advent of advanced affordable electronics and mobile wireless technology. The growing demand for bandwidth has sparked increased discussions in the microwave remote sensing community of how to respond to this crowded spectrum environment and how to deal with the consequent issues of radio frequency interference (RFI). The National Research Council (NRC) published a study in 2010, "Spectrum Management for Science in the 21st Century" [1], that examined the increasing difficulties encountered by passive microwave measurements in the presence of the expanding worldwide commercial and governmental occupancy of the radio spectrum. The challenges faced by passive sensors also have been summarized in a 2014 IEEE Geoscience and Remote Sensing Magazine article [2]. Recognizing that active microwave sensors also face spectrum-related issues, NASA later commissioned the NRC to perform a similar study, "A Strategy for Active Remote Sensing Amid Increased Demand for Radio Spectrum," which was recently published in July 2015 [3]. (In this article, the report will be abbreviated as the NRC Active Sensing Report.) This report addresses the spectrum issues faced by active science sensors, primarily radars, and makes recommendations to government, industry, and the remote sensing community going forward. The report considers multiple types of active sensors including ground-based operational weather radars, ionospheric sensing radar, and radar astronomy. This article focuses on spectrum topics related primarily to Earth remote sensing from aircraft and spacecraft.