Australian SKA Pathfinder: Digital signal processing implementation and early engineering test array results

The Boolardy Engineering Test Array (BETA) is the first prototype of the Australian Square Kilometer Array Pathfinder (ASKAP), a new radio telescope that is pioneering the use of Phased Array Feed (PAF) technology in radio astronomy to provide instantaneous wide field-of-view imaging. BETA consists of six 12 meter parabolic antennas, each equipped with a 188-element PAF at the focus and a signal processing system capable of imaging an instantaneous 7 square degree field-of-view with a bandwidth of 300MHz at a resolution of 18kHz. In this paper we describe the architecture of the digital signal processing chain and its implementation on reconfigurable hardware based on Field-Programmable Gate Array (FPGA) technology. We present early engineering results taken by the instrument during commissioning trials at the Murchison Radio Observatory (MRO) in remote Western Australia. In particular, we present the first multi-beam image of an astronomical source captured with a PAF-based interferometer.