RFI Mitigation in Microwave Radiometry Using the Karhunen–Loève Transform

This study presents a new signal-processing method to mitigate radio-frequency interference (RFI), based on the Karhunen–Loève transform (KLT). The main property of this method is that it is adaptive and RFI-agnostic, that is, it can potentially mitigate any type of RFI waveform. It is based on the estimation of the covariance matrix of the process, and the derivation of a basis that spans the RFI subspace. The methodology to find this basis is explained in detail. The theoretical performance obtained using KLT is explored by simulations, along with the evaluation of the influence of the system parameters. In addition, a couple of examples with real data are provided.