Effectiveness of the Correlator Field of View Weighting Technique in Source Attenuation

The science requirements of next-generation radio telescope arrays present a new set of challenges to traditional imaging and data processing techniques. Instruments such as the MWA and SKA implementing large numbers of small diameter (LNSD) elements have a naturally large field-of-view. In order to achieve high image fidelity and dynamic range, signal contributions from off-center sources must be reduced a task traditionally requiring imaging of the full field-of-view. However, implementing this process under proposed designs requires unreasonable computational speeds while also generating unmanageable volumes of data. One approach to this problem involves dynamic control over the field-of-view, implemented in software as a weighting algorithm within the integration routine of an advanced correlator. Using this technique we can effectively reduce the contribution from sources outside the region of interest, and in some cases dramatically reduce the volume of data exiting the correlator. Herein we focus on verifying the effectiveness of this technique, implemented through the MIT Array Performance Simulator (MAPS). The limitations and design requirements of this approach are also evaluated, including the impact of variable levels of radio frequency interference (RFI) excision on image fidelity and off-center source signal rejection.