RFI mitigation and detection for the SMAP radar

The planned Soil Moisture Active Passive (SMAP) mission1 will use both active radar and passive radiometer instruments at L-Band to measure and monitor both soil moisture and freeze/thaw state globally. The frequency band allocated for the SMAP radar is shared with the Global Navigation Satellite Systems and ground-based radiolocation services. Signals from those users present significant sources of anthropogenic radio frequency interference (RFI) which contaminate the radar measurements. To mitigate RFI, the radar is designed with tunable operating frequency, which allows the center frequency to be tuned to avoid RFI. The filtering scheme in the receiver is configured to get a high level of RFI suppression. To meet the high accuracy measurement requirements, RFI detection and correction will be required during ground data processing. Some candidate algorithms have been evaluated, and they have been tested against simulated SMAP data derived from the PALSAR data.