A fast, wide-field, and real-time imaging prototype for large aperture arrays

Real-time processing on sub-millisecond timescales is needed to catch fast transients such as fast radio bursts (FRBs) and prompt electromagnetic counterparts to gravitational-wave mergers, where immediate localization enables rapid multi-wavelength follow-up. Wide-field aperture arrays are now being built with thousands to tens of thousands of elements, but traditional correlator architectures scale as O(N^2), making large arrays computationally expensive in bandwidth, power, and limiting field of view, angular resolution, or duty cycle.

The paper describes an FPGA-based prototype of E-field Parallel Imaging Correlator (EPIC), an alternative that images the full field directly and avoids forming pairwise correlations, achieving O(N log N) scaling for dense arrays. EPIC had already been demonstrated on the Long Wavelength Array (LWA) station in Sevilleta using GPUs, but GPU implementations hit memory-bandwidth limits in low-bitwidth gridding and FFT workloads; the FPGA implementation exploits highly parallel FFT pipelines to improve efficiency and reduce power consumption.

Using preliminary results, the authors evaluate the prototype's scalability and discuss its suitability for next-generation instruments including SKA-Low and mid-frequency aperture arrays.