Radio-Frequency Interference Mitigation for the Soil Moisture Active Passive Microwave Radiometer
Current spaceborne radiometers do not achieve the required spatial resolution demanded by the scientific community due to antenna-size technological limitations. In recent years, several space agencies have been studying aperture synthesis interferometric radiometers as a way of overcoming these limitations, which are more evident at low microwave frequencies (e.g., at L-band), where sea surface salinity and soil moisture can be monitored. Interference is an important issue in any remote sensing instrument, but it is crucial in microwave radiometers, since the signal being measured is the spontaneous thermal noise emission. Interference analyses already exist for classic radiometers. The objective of this paper is the analysis of RF interference on interferometric radiometers. The study involves the analysis of possible interference sources that may affect the performance of such systems at L-band: 1) nearby emissions from radars, non-Geo-Stationary Orbit (GSO) and Mobile Satellite Services (GSO-MSS), 2) harmonics of lower frequency emissions, and 3) possible jamming.