Radio frequency interference mitigation in radioastronomy

RFI is increasingly a problem for radioastronomy with the ever expanding use of the radio spectrum by both the communications industry (transmitting) and the radioastronomers (receiving). Regulation can protect a few windows in the radio spectrum, but many experiments now need to access parts of the spectrum outside the reserved regions. Spectral lines, for example, may be significantly Doppler-shifted, and therefore require an observation window far from their rest frequencies. A variety of RFI mitigation techniques have been developed in recent years. Most of these have analogues in other disciplines, but the specifics of the radioastronomers´ experiments allow for some interesting refinements. The astronomer is generally not interested in recovering a symbol stream in the data, but rather wants a more general description of the statistics. This makes a number of post-correlation techniques valuable and computationally viable.