Title of Presentation: Development of an Agile Digital Detector for RFI Detection and Mitigation on Spaceborne Radiometers

Primary (Corresponding) Author: Christopher Ruf

Organization of Primary Author: University of Michigan

Co-Authors: Steve Rogacki, Cut Cooper, Steve Gross, Jeff Piepmeier and Joel Johnson

Abstract: Passive microwave observations for Earth science are becoming increasingly contaminated by Radio Frequency Interference (RFI) from man made sources of emission such as telecommunication transmissions and civilian and military radars. If the RFI has a very high power level, it can usually be identified and flagged. Much more ubiquitous are the cases where the RFI has a relatively low power level, in which case it can be mistaken for the variability in the observations that is expected of natural geophysical signals. This can have a very significant detrimental effect on the value of archival data records, such as are used for climate studies, and on operational uses of the measurements, e.g. for use as observational constraints on a numerical weather forecast.

A new type of detector has been developed that can reliably identify and remove RFI from radiometer observations even when it has an extremely low power level. The Agile Digital Detector (ADD) can discriminate between RFI and natural thermal emission signals by directly measuring higher order moments of the signal than the variance that is traditionally measured. After detection, the ADD then uses high-resolution temporal and spectral filtering methods to selectively remove the RFI. A series of field campaigns has been conducted to evaluate the relationship between design parameters of the ADD and its ability to detect and remove RFI. A candidate spaceflight design has been determined based on these relationships and on the expected requirements of upcoming earth science microwave radiometer missions, as identified in the recent NRC Decadal Survey. Details of the spaceflight ADD performance requirements and design will be presented.