Spatial filtering of near-field radio frequency interference at a LOFAR LBA station
MetadataShow full item record
© 2016 IEEE. In preparation for the SKA, many new RFI (radio frequency interference) mitigation algorithms have been developed. However, these algorithms usually assume that the RFI source is in the far-field and that the array is calibrated. In this paper, the recovery of astronomical signals from uncalibrated RFI-corrupted LOFAR visibility data using spatial filtering methods are presented. For this demonstration, a near-field continuous-wave RFI source was generated by a hexacopter that was flown around one of the LOFAR LBA (low-band antenna) arrays. Four spatial filtering methods were applied to the RFI contaminated data: orthogonal projection, orthogonal projection with subspace bias correction, oblique projection and subspace subtraction. Overall, orthogonal projection with subspace bias correction performed the best, however it requires that the RFI source moves relative to the array and it is computationally expensive. Oblique projection performs similar to orthogonal projection with subspace bias correction when point sources are to be recovered and is furthermore considerably less computationally expensive. Subspace subtraction is a suitable alternative if a large field of view is to be recovered at a relatively low computational cost.
Showing items related by title, author, creator and subject.
Gupta, Sunil Kumar (2011)The growing number of information sources has given rise to joint analysis. While the research community has mainly focused on analyzing data from a single source, there has been relatively few attempts on jointly analyzing ...
Brown, D.; Li, J.; Calo, Victor; Ghommem, M.; Efendiev, Y. (2014)With the recent interest in shale gas, an understanding of the flow mechanisms at the pore scale and beyond is necessary, which has attracted a lot of interest from both industry and academia. One of the suggested algorithms ...
Ghommem, M.; Calo, Victor; Efendiev, Y.; Gildin, E. (2013)In this paper, we apply mode decomposition and interpolatory projection methods to speed up simulations of two-phase flows in highly heterogeneous porous media. We propose intrusive and non-intrusive model reduction ...