Unmanned Aerial System and Spaceflight Microwave Radiometers’ Radio-Frequency Interference Direct Detection and Science Data Recovery Based on the Hilbert-Huang Transform for Two Dimensions

Spacecraft advanced passive microwave radiometry instrument makes use of natural thermal emissions to remotely sense Earth phenomena of interest to science in the L-band (soil moisture, for example). Soil moisture is a strategic parameter whilst 8” of soil feed 7.046 billion people. Here a terrestrial signal-to-space suffers less attenuation by the intervening canopy or atmosphere. Unfortunately, relative insensitivity of the L-band region to atmospheric effects also makes it an extremely attractive spectral range for wireless radar & cell communications that are causing radio frequency interference (RFI) with the signal of interest.

State-of-the-art radiometry technology detects an RFI event and deletes the entire contaminated measurement point.  Excision of just the RFI component from the composite signal is presently a tall challenge task. This IRAD-FY14 will research and develop new technologies to solve this task based on the Hilbert-Huang Transform for two dimensions (2D HHT2).

The three goals of this IRAD are:

1.1 Research and develop the Hilbert-Huang Transform for 2D second and last component – the Hilbert Spectral Analysis for 2D (HSA2) and complete the HHT2 theory;

1.2 Develop the engineering tool for a direct decomposition of the RFI-contaminated signal into 2D or bi-dimensional Intrinsic Mode functions (BIMFs) and use the BIMFs to recover RFI-contaminated science data points by HSA2;

1.3 Verify the new technology tool prototype by a controlled drone experiment at Wallops, comprising a miniature radiometer, a controlled RFI source, and science data processing on the ground.