Engineering topics

Beaudoin, Christopher

Publications and source records attributed to Beaudoin, Christopher.

4 records

NASA NTRS2013

VLBI Digital-Backend Intercomparison Test Report

Issues related to digital-backend (DBE) systems can be difficult to evaluate in either local tests or actual VLBI experiments. The 2nd DBE intercomparison workshop at Haystack Observatory on 25-26 October 2012 provided a forum to explicitly address validation and interoperability issues among independent global developers of DBE equipment. This special report discusses the workshop. It identifies DBE systems that were tested at the workshop, describes the test objectives and procedures, and reports and discusses the results of the testing.

Whitney, Alan↗

NASA NTRS2010

Post-Correlation Processing for the VLBI2010 Proof-of-Concept System

For the past three years, the MIT Haystack Observatory and the broadband team have been developing a proof-of-concept broadband geodetic VLBI microwave (2-12 GHz) receiver. Also on-going at Haystack is the development of post-correlation processing needed to extract the geodetic observables. Using this processing, the first fully-phase-calibrated geodetic fringes have been produced from observations conducted with the proof-of-concept system. The results we present show that the phase-calibrated phase residuals from four 512 MHz bands spanning 2 GHz have an RMS phase variation of 8deg which corresponds to a delay uncertainty of 12 ps.

Beaudoin, Christopher↗

NASA NTRS2010

Development of a Compact Eleven Feed Cryostat for the Patriot 12-m Antenna System

The Eleven antenna has constant beam width, constant phase center location, and low spillover over a decade bandwidth. Therefore, it can feed a reflector for high aperture efficiency (also called feed efficiency). It is equally important that the feed efficiency and its subefficiencies not be degraded significantly by installing the feed in a cryostat. The MIT Haystack Observatory, with guidance from Onsala Space Observatory and Chalmers University, has been working to integrate the Eleven antenna into a compact cryostat suitable for the Patriot 12-m antenna. Since the analysis of the feed efficiencies in this presentation is purely computational, we first demonstrate the validity of the computed results by comparing them to measurements. Subsequently, we analyze the dependence of the cryostat size on the feed efficiencies, and, lastly, the Patriot 12-m subreflector is incorporated into the computational model to assess the overall broadband efficiency of the antenna system.

Beaudoin, Christopher↗

NASA NTRS2010

The Wettzell System Monitoring Concept and First Realizations

Automated monitoring of operational system parameters for the geodetic space techniques is becoming more important in order to improve the geodetic data and to ensure the safety and stability of automatic and remote-controlled observations. Therefore, the Wettzell group has developed the system monitoring software, SysMon, which is based on a reliable, remotely-controllable hardware/software realization. A multi-layered data logging system based on a fanless, robust industrial PC with an internal database system is used to collect data from several external, serial, bus, or PCI-based sensors. The internal communication is realized with Remote Procedure Calls (RPC) and uses generative programming with the interface software generator idl2rpc.pl developed at Wettzell. Each data monitoring stream can be configured individually via configuration files to define the logging rates or analog-digital-conversion parameters. First realizations are currently installed at the new laser ranging system at Wettzell to address safety issues and at the VLBI station O Higgins as a meteorological data logger. The system monitoring concept should be realized for the Wettzell radio telescope in the near future.

Ettl, Martin↗