Development and Evaluation of the Ethernet Interface(s) for the Monitoring and Control System of a New Beamforming Radio Telescope

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Date
2010-08-06
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Virginia Tech
Abstract

The Long Wavelength Array (LWA) is a large multi-purpose radio telescope, operating in frequencies between 10 and 88 MHz, designed for both long-wavelength astrophysics and ionospheric science. The LWA will eventually consist of 53 "stations", each consisting of 256 pairs of crossed-dipole antennas whose signals are formed into beams. The Monitoring and Control System (MCS), a subsystem of each LWA station, controls the station's subsystems and also monitors their status. This thesis addresses the interface-related features of MCS. The physical interface of the MCS with each subsystem is a Gigabit Ethernet connection and the interface protocol is User Datagram Protocol (UDP). An analysis of the throughput obtained through the interface using UDP is compared to that achieved using Transmission Control Protocol (TCP). It is seen that the throughput with UDP is 15% better than with TCP, and that UDP is a better choice for the given requirements. Implementation of a new ionospheric calibration scheme requires that the MCS be capable of repointing between astronomical sources on a 5 ms time scale. The rate at which beams can be repointed is analyzed. It is confirmed that MCS is at least 2 orders of magnitude faster than necessary, and is limited by the ethernet network throughput. Python software that facilitates the development and testing of MCS and other subsystems have been developed, and are described.

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Keywords
Monitoring and Control System, Long Wavelength Array
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