Digital Complex Correlator for a C-band Polarimetry survey

TL;DR

This paper presents a novel digital complex correlator system designed for C-band polarimetry surveys, enabling detailed mapping of the Milky Way's polarization with cost-effective FPGA-based technology.

Contribution

It introduces a fully digital, FPGA-based complex correlator for polarimetry, suitable for large sky surveys and based on COTS components, advancing survey instrumentation.

Findings

Successful implementation of a digital correlator with FPGA technology.

Capability to output all four Stokes parameters for polarization analysis.

Cost-effective design suitable for large-scale sky surveys.

Abstract

The international Galactic Emission Mapping project aims to map and characterize the polarization field of the Milky Way. In Portugal it will cartograph the C-band sky polarized emission of the Northern Hemisphere and provide templates for map calibration and foreground control of microwave space probes like ESA Planck Surveyor mission. The receiver system is equipped with a novel receiver with a full digital back-end using an Altera Field Programmable Gate Array, having a very favorable cost/performance relation. This new digital backend comprises a base-band complex cross-correlator outputting the four Stokes parameters of the incoming polarized radiation. In this document we describe the design and implementation of the complex correlator using COTS components and a processing FPGA, detailing the method applied in the several algorithm stages and suitable for large sky area surveys.