Standard for Remote Sensing Frequency Band Radio Frequency Interference (RFI) Impact Assessment

Radio Frequency Interference (RFI) originating either from radio-communication services in nearby frequency bands or from sources transmitting illegally or above permissible power limits is affecting spaceborne passive and active microwave Earth Observation instruments.

Microwave (MW) sounders are designed to measure the total amount of radiative power in the form of brightness temperature. A 230 K natural occurring signal that also has a 5 K anthropogenic sourced signal would be measured by the MW sounder as a 235 K brightness temperature. Similarly, a 235 K naturally occurring signal without any added anthropogenic sourced signals would also be measured as 235 K. The two scenarios are indistinguishable from each other in current MW sounders. Similar issues are expected with other types of remote active and passive band sensors. Efforts are underway to develop methods and technologies that may reduce the risk of data corruption and loss.

This non-natural radio frequency (RF) contamination will only continue to increase in intensity and number. This growth has been observed by the spectrum management community for decades. Information is needed for spectrum managers to allocate the efforts to enforce radio-regulations, for space agencies to protect the remote sensing instruments that will provide more benefit to society, and/or to allocate efforts in RFI mitigation techniques, and for researchers to understand the errors associated with their retrievals.

The IEEE Geoscience and Remote Sensing Society/Standards Committee (GRSS/SC) has initiated the development of a standard to address the concerns for RFI-caused degradation to remote active and passive sensors. This standard will provide a standard to quantitatively assess RFI on the affected frequency bands. This information is expected to be used to inform policy decision makers and the public regarding the status, over time, of anthropogenic caused RFI in any given remote sensing frequency band and its impact on remote sensing operations and products. Specifically, this standard is intended to be used in RFI impact evaluations and monitoring of frequency bands allocated to space-based remote sensing. The standard will provide a definition of RFI as it relates to space-based remote sensing operations.