Correlators for Interferometric Radiometry in Remote Sensing Applications, A Scaling Perspective
Paper in proceedings, 2018
Correlators are extensively used in the field of radio interferometry. Two different types are considered for two applications; autocorrelators for spectrometry and cross-correlators for aperture synthesis. We concentrate on satellite-based applications where power budgets are very restrictive. Several satellites are already employing correlators for interferometric measurements, and future projects are targeting even larger systems in terms of spectral channels in the case of spectrometry and baseline counts in the case of aperture synthesis. Thus, it is important to develop correlators with increasing channel count, either using ASIC technology scaling or by constructing larger systems from several ASICs. Building on earlier ASIC designs, we examine how larger correlator systems can be constructed and the implications this has, in terms of power dissipation, system complexity, and ASIC count. Our findings indicate that, for large systems, having a very high channel count per ASIC is indeed of interest for keeping system complexity and power dissipation down by reducing both ASIC and I/O count, especially for cross-correlators.