Radio astronomy forms an interesting application area for array signal processing techniques. Current synthesis imaging telescopes consist of a small number of identical dishes, which track a fixed patch in the sky and produce estimates of the time-varying spatial covariance matrix. The observations sometimes are distorted by interference, e.g., from radio, TV, radar or satellite transmissions. We describe some of the tools that array signal processing offers to filter out the interference, based on eigenvalue decompositions and factor analysis, which is a more general technique applicable to partially calibrated arrays. We consider detection of interference, spatial filtering techniques using projections, and discuss how a reference antenna pointed at the interferer can improve the performance. We also consider image formation and its relation to beamforming.
Bibliographical noteFunding Information:
We would like to thank S. van der Tol at TU Delft and our project partners at ASTRON for the very useful collaboration. This work was supported in part by the STW under DEL77-4476, DTC.5893. This overview paper covers material from several prior publications from the authors.
- Array signal processing
- Interference mitigation
- Radio astronomy