Spatial Filtering of RF Interference in Radio Astronomy Using a Reference Antenna Array

Radio astronomical observations are increasingly contaminated by RF interference. Assuming an array of telescopes, a previous technique considered spatial filtering based on projecting out the interferer array signature vector. A disadvantage is that this effectively reduces the array by one (expensive) telescope. In this paper, we consider extending the astronomical array with a reference antenna array, and develop spatial filtering algorithms for this situation. The information from the reference antennas improves the quality of the interferer signature vector estimation, hence more of the interference can be projected out. Moreover, since only the covariance data of the astronomical array has to be reconstructed, the conditioning of the problem improves as well. The algorithms are tested both on simulated and experimental data.