10th IVS Technical Operations Workshop


MIT Haystack Observatory
5-9 May 2019


TOW 2019: Course Description

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There are four types of courses to be offered at the Technical Operations Workshop (TOW). All workshop and seminar classes have a time slot of 75 minutes; then a 15-minute overlay time follows to be used for final questions and change of class rooms for the subsequent class. Lectures have a time slot of 30 minutes, except for the VLBI Basics lecture which is 60 minutes long.

  • Operations Workshops are hands-on sessions with a maximum of about 5 participants each. Each member of the class will have an opportunity to participate actively in the training.

  • Maintenance Workshops are presentations to an audience of 10-20 people. The classes will begin with instruction and demonstration, and there may be some hands-on training. A large fraction of the time is allowed for discussion and question/answer periods. The subject matter includes a variety of topics.

  • Seminars are presentations including demonstrations to an audience of 20-60 people, depending on the topic. The subject matter includes a variety of special interest topics.

  • Lectures are intended for a general audience. The subject matter includes topics that we believe are of interest to everyone, or include announcements or information that everyone should be aware of. All attendees at the workshop will be scheduled for the lectures.





Operations Workshops

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Operations Workshops are hands-on sessions with a maximum of about 5-7 participants each.

Title: VLBI Session Pre-checks and IVS Operations
Teachers:Mike Poirier, Roger Hammargren, Alex Burns
Grade level:Beginners and advanced levels; new material on the VGOS operation will be included.
Description: This is a double-length class that will include both pre-checks and operations. This class is offered with two formats. One format is for students with stronger English skills and will move at a faster pace. The other format is for students with weaker English skills, will move at slower pace, and have more pauses for material that may be difficult to understand in translation. Pre-checks: We will practice all of the procedures and operational tests that should be performed before each experiment to insure that all of the equipment is set up and working properly, starting with drudging the schedule file and ending with pre-session e-mail to ops. Pointing and gain calibration will be covered in separate workshops. This class is for people who use the PC Field System to control data racks such as the Mark IV, VLBA, DBBC and RDBE. The Mark5B and Mark6 will be discussed at the operational level. The class will use the Westford VGOS system and the Mark IV, with appropriate notes made about differences for other systems. The RDBE and Updown converters will be discussed in detail. Operations: We will practice experiment operations from starting the schedule to the post-session operational report with hands-on by students during the session. The use of the "logpl" program for plotting data from the log during and after the experiment will be demonstrated along with other tools available found in the PCFS. This class will be held at Westford, using the VGOS RDBE and Mark 6 recorder.

Title: Operational Recovery from System Failures
Teachers:Mike Poirier, Roger Hammargren, Alex Burns
Grade level:Advanced level with frequent student interaction.
Description:Loss of data issues compiled from 2014 from all stations will be discussed in detail with proper recovery and simulations. This will be open forum with input and suggestions from all advanced students, many that have experienced these issues. Topics will include: (1) Power failure recovery, starting from scratch. (2) Telescope failure, stuck, poor offsets, slewing. (3) Mark 5 and 6 issues including operational recovery guidelines and power supply repair. (4) Maser signal failures including 5 MHz and 1PPS at the operational level to recover. (5) Data rack failure from Video Converters, Receiver and IF issues, Phase calibration, RDBE and Up-Down converters. Station repair guidelines and proper tools and test equipment for students that may have these skills.

Title: Operational Use of Mark 6
Teachers:Chet Ruszczyk
Grade level:Advanced
Description:This class will provide further details and explanations of operating Mark 6 systems at stations extending on what is covered in the VLBI Session Pre-checks and IVS Operations class. In addition details will be given on the usage of Mark 6 systems when attached to a correlator. There are commonalities between the two deployment options; however, there are also operational peculiarities for each option that early users should be aware of.

Title: Cryogenic System and Receiver Maintenance
Teachers:Christian Plötz
Grade level:Beginners.
Description:This workshop will address cryogenic system and receiver maintenance from the operational perspective. The goal is to improve system reliability, reduce downtime, and lower operational cost. Workshop participants will receive helpful hints for recovery from vacuum failures, contaminated helium systems, and the use of standardized maintenance procedures with some common pitfalls identified. General cryogenic "Do's and Don'ts" will be discussed. This session will not address the theory of cryogenics or the internal workings of a dewar.






Maintenance Workshops

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Maintenance workshops are presentations or demonstrations to an audience of 10 or fewer people, with discussion and questions. There may be some hands-on training.

Title: Automated Pointing Models Using the FS
Teachers:Ed Himwich
Grade level:Beginners and advanced levels.
Description: This class will be offered at two levels. One level will concentrate on basics for students who do not have much experience with the tools presented and want an introduction. The other level will be for students with more experience or want to address more advanced topics. The course will cover basic support for pointing measurements in the Field System. It will also include a demonstration of the "pdplt" program for analyzing pointing data. It will describe basic principles for configuring the mdlpo.ctl and ctlpo.ctl files that control the automated pointing data acquisition and delogging processes. Gain calibration will be covered in separate workshops.

Title: Antenna Gain Calibration
Teachers:Michael Lindqvist
Grade level:Beginners; some new material.
Description:This course covers using ONOFF and GNPLT. Instruction will be given on the preparation and execution of ONOFF for the automatic acquisition of amplitude calibration data. Attendees will learn about the necessary procedure files, methods of measuring noise diode temperature and gain curves, and the interpretation of the resulting log files. The course will provide basic instruction on analyzing gain calibration data with GNPLT. Typical tasks (such as calibration of Tcal and gain curves) will be described step-by-step, a general discussion about GNPLT data analysis capabilities will also be held. Some time will be reserved to include the possibility of giving feedback and requesting improvements in the features of the gain calibration tools.

Title: RFI Sources, Identification, Mitigation
Teachers:Jose A. Lopez-Perez
Grade level:Beginners; some new material.
Description:This workshop will cover the effects of radio interference on VLBI observations, sources and identification of RFI, and possible mitigation techniques for RFI. Methods for conducting an RFI survey will be reviewed, and initial results from broadband surveys undertaken for the VGOS project at several sites will be summarized. A more detailed look at the practical issues and results of such a survey will be presented for the case of the broadband surveys conducted by IGN Yebes Observatory at several locations in Europe. In addition, information is given about RFI regulations and protection levels, how to perform a simple RFI compatibility study, and how to compute RFI strength (in E-field units) to be able to compare the received RFI power with the protection levels.

Title: Phase Cal Basics and RF System Testing
Teachers:Ganesh Rajagopalan
Grade level:Beginners
Description:The phase calibration system is the primary means for ensuring that instrumental effects in the receiver and VLBI terminal do not corrupt the group delay measurements. This course will cover the basic concepts and hardware implementation of the calibration system, including the Mark IV cable measurement system. The nature and causes of spurious signals, which can degrade the calibration accuracy, will be described. Following the phase cal basics we will review the fundamentals of measuring a power spectrum with an analog RF or FFT-based spectrum analyzer. Applications to VLBI system testing and trouble-shooting will be discussed and demonstrated, with a particular emphasis on phase noise and modulation in LO and phase calibration systems. The detection of spurious phase cal signals with a spectrum analyzer will also be treated, along with the diagnosis and cure of such signals.

Title: Advanced Pre-checks and Operations
Teachers:Ganesh Rajagopalan, Ed Himwich
Grade level:Beginners
Description:This course is intended to provide a description of the tests that stations should periodically perform to evaluate the performance of their station. These checks are more advanced than the ones covered in the VLBI Session Pre-checks and IVS Operations course, but most are covered in more detail in other courses. This course works through the list of checks, explains the reasons for the tests, provides some tips on performing them, how to use systests scripts for automating and analyzing measurements, and a chance to ask questions about them. The systests scripts are an important tool for testing and verification for stations that have Mark IV Decoders. In order to have a full grounding in this material it is recommended that anyone signing up for this course should also take some other courses unless they are already familiar with the material in these courses. The recommended other courses are: RFI Sources, Identification, Mitigation and Phase Cal Basics and RF System Testing. Some additional material on troubleshooting not covered in other courses will be presented here. This course will also give an introduction on how VLBI electronics works.

Title: Understanding Correlator Feedback
Teachers:Phillip Haftings, Andrew Sargent
Grade level:Beginners; new material
Description:This seminar covers the coordination of observations, the logistics of media distribution, the set-up of correlation, the analysis of results and the feedback to stations. Particular emphasis will be on correlator-station communication from the station reports and logs to correlator feedback. Representatives from the correlators will be available for discussions and advice on issues regarding your station.






Seminars

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Seminars are presentations including demonstrations to an audience of 10 or more people, depending on the topic.

Title: Pointing and Amplitude Calibration in Theory and Practice
Teachers:Bob Campbell
Grade level:Beginners; some new material
Description:In this course students will learn why accurate pointing corrections must be known for all parts of the sky to be observed, and how pointing errors affect geodetic and astronomical results. Students will learn how SEFD and system temperature measurements are related, how to check the focus, how to make SEFD measurements, how to measure a gain curve, which sources are best for the SEFD measurements, how weather can affect the measurements and results, and how the SEFD measurements are used for data analysis and scheduling. We will discuss measurement equipment and how it may affect the results if care is not taken. We will also describe the use of the ANTABFS suite of scripts for producing well-calibrated and formatted system temperature and gain curve tables, suitable for use in the common data analysis packages. It will include some explanation of how the information is obtained and why good quality amplitude calibration is important; and some examples of typical errors will be presented.

Title: High-accuracy Time and Frequency in VLBI
Teachers:Katie Pazamickas and Richard Hambly
Grade level:Beginners with some Advanced material; class contains new material
Description:This presentation will provide an overview of the use of high-accuracy time and frequency in VLBI. This will include a discussion of all the "clocks" used in VLBI (Hydrogen Masers, GPS timing clocks, the clocks inside the Field System computer and the clock information needed by the correlators) and how they need to be tied together in order to guarantee successful VLBI measurements. Some focus will be put on the different types of masers with block diagrams as well as generalized operational procedures.

Title: Topics in FS Station Software Coding
Teachers:Ed Himwich
Grade level:Advanced
Description:This session will be organized as a group discussion/demonstration. It will provide an opportunity for people to present questions they have about implementing specific station features and to get advice on how to do it. There is no separate lecture this year covering more of the basics of station software coding, but the notes from previous years will be included and that topics can addressed at some level depending on people's interests and the time available. A brief of overview of the programming interface to the new FS display server will be presented.

Title: Setup and Operations of the DBBC2
Teachers:Uwe Bach
Grade level:All levels; some new material
Description:This seminar will give an introduction into the setup and operations of the digital backend DBBC2. The DBBC2 is fully integrated into the Field System and most of the EVN stations use the DBBC2 for astronomical and geodetic VLBI observations. It will be shown how to install, test, and operate a DBBC to replace an existing analog backend. The DBBC2 is capable of processing 8 RF/IF inputs from different bands and/or polarization between 10 MHz and 3072 MHz (with ADB2) to produce a group of up to 64 output data channels using two VSI output connectors at a maximum data rate of 2 Gbps each. It is fully compatible to the existing analog VLBI backends, but at the same time provides the flexibility to observe at higher bandwidth and recording rates to meet the future VGOS observation capability.

Title: Setup and Operations with the DBBC3
Teachers:Sven Dornbusch
Grade level:All levels; new material
Description:This seminar will give an introduction into the setup and operations of the digital backend DBBC3. There are three different modes available: DSC, OCT, and DDC. We will give a description of those modes and their main observing applications. In its digital down conversion mode, the DBBC3 is in the process to be fully integrated into the Field System and a number of IVS stations started to use the DBBC3 for regular VLBI observations. It will be shown how to install, test, and operate a DBBC3, which is capable of processing a maximum of 8 RF/IF with each 4-GHz bandwidth inputs from different bands and/or polarizations to produce a group of up to 128 output data channels, using four 10GE output connections at a maximum data rate of 8 Gbps each. During the course the calibration process required by the system will be described; this procedure is now fully automated, but it still requires the knowledge and understanding of the process it is performing in order to evaluate the results.

Title: R2DBE Setup and Operations
Teachers:Chet Ruszczyk, Reggie Wilcox
Grade level:Beginners; new material
Description:This seminar will give an introduction into the installation and operation of the VGOS compliant R2DBE-G digital backend and the RDBE-G.

Title: e-transfer Operations
Teachers:Jason SooHoo
Grade level:Beginners; new material.
Description:This course will cover operational aspects of performing e-transfers of data between stations and correlators.

Title: System Monitoring using e-RemoteCtrl and Zabbix in the JumpingJIVE Context
Teachers:Alexander Neidhardt
Grade level:Beginners; some new material.
Description:We describe general aspects of a passive monitoring of telescope sites collecting system and analysis parameters in real-time. The data are evaluated and trigger points define alarm levels according to the severity of a problem situation. Focus is laid on supporting infrastructure for the staff at the telescopes. The extended version of the original e-RemoteCtrl software directly supports the presentation and monitoring of 110 parameters from the NASA Field System using Web pages on regular Web browsers. In combination with the enterprise-class open source monitoring solution ZABBIX and its agents on different PCs, a centralized monitoring server at an observatory can support this monitoring to give staff a better overview of the systems. Additionally, it is possible to join a central monitoring network developed in the EU-funded project “Jumping JIVE” and located at Wettzell observatory and JIVE ERIC, Dwingeloo in the future. Sites can decide to open Web page access and proxy ports over securely encrypted tunnels to the centralized server, so that status information are visible there in real-time as well. This interface can also be used to support the task force for seamless auxiliary data of the IVS. Possibilities and restrictions can be discussed during the course.

Title: VLBI Data Acquisition, Formats, Transfer and Tools
Teachers:Harro Verkouter
Grade level:Beginners; some new material.
Description:This workshop will go through the whole VLBI data acquisition chain, touch down at the actual recording hardware one may encounter in the field, illuminate the different data formats in use in VLBI that e.g. a correlator may be faced with and finishes off with an in-depth section on the current high-speed Ethernet recorders, with a sugar coating of what tools have been developed in the European VLBI Network that hopefully make working with those even more pleasant.

Title: Programming Station Code in C++ and Automating Processes for the NASA Field System
Teachers:Alexander Neidhardt
Grade level:Beginners; new material
Description:We discuss various topics about getting in interaction with the NASA Field System. Using class-based designs and a converter module, programs like “stqkr” or “antcn” can be upgraded to object-oriented programs. In addition, the Field System already supports access points to automate tasks, like predefined session starts. But additional add-ons can also be used, to automatically download, prepare, arrange, start, and attend sessions. The course will discuss methods for risk analysis and presents the ideas and some scripts developed at Wettzell on the way to transfer all VLBI telescopes at the Wettzell observatory to mostly unattended systems.

Title: Station Monitoring with MAS
Teachers:David Horsley
Grade level:Beginners; some new material
Description:This course will introduce the Monitoring and Archiving System (MAS) for VLBI station data. This is a suite of open-source monitoring tools originally developed for Dev-Ops, with some additional tools for collecting data from the Field System. We will cover system recommendations, data-flow, database queries, alerting, and building your own collectors for the system.

Title: Linux System Administration and FSL10
Teachers:David Horsley
Grade level:Beginners; some new material
Description:This course covers material outside the normal course of experiment operations. We will address some general aspects of managing Field System computers and other Linux systems. Particular emphasis will be placed on changes in the Debian Stretch based Field System Linux 10 and obstacles stations may face in upgrading.






Lectures

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Lectures are intended for a general audience. All attendees at the workshop are welcome to attend the lectures.

Title: VLBI Basics
Teachers:Pedro Elosegui
Grade level:Beginners
Description:This lecture will describe the VLBI technique from scheduling to data capture, to correlation and to analysis. It will cover the basic concept, observational system, delay resolution function, correlation, and observables.

Title: Impact of Operations on Data Analysis
Teachers:Ed Himwich, Mario Bérubé
Grade level:Beginners
Description:This course will describe the effect on geodetic data analysis of various problems during data acquisition. Problems such as clock breaks, bad tracks, parity errors, pointing errors, warm receivers, and late starts will be covered. The importance of the stability of the signal chain and the delay of the VLBI signal through it (the so-called “peculiar offset”) will be discussed.

Title: Science Overview
Teachers:Sergei Bolotin
Grade level:Beginners; some new material
Description:An overview of the scientific goals of geodetic and astrometric programs will be presented. Particular emphasis will be placed on reference frames which are the fundamental products of VLBI. Specific topics will include re-observing the VLBA Calibrator Surveys for ICRF3, ITRF2014, and near-field correlation.

Title: Field System Near Term Future Plans
Teachers:Ed Himwich
Grade level:Beginners and advanced levels.
Description:This presentation will cover the immediate and long-term plans for Field System development. The ongoing collaboration and cooperation on the Field System among various groups will be described.

Title: Instrumentation Developments for VGOS at IGN Yebes Observatory
Teachers:Jose A. Lopez-Perez
Grade level:Beginners; new material.
Description:Yebes Observatory (IGN, Spain) is developing the instrumentation for its RAEGE network of VGOS radio telescopes as well as for other institutions, like NMA (Norway) and FGI (Finland), who are also working on completing their VGOS antennas. These developments include new VGOS receivers, low-noise amplifiers and hybrid circuits, feed optimization, phase-cal and noise-cal units, cryogenic cooling control units, RFI monitorization, and telescope control.

Title: Haystack VGOS Signal Chain
Teachers:Chet Ruszczyk
Grade level:Beginners; new material.
Description:In this lecture we will provide a description of the Haystack VGOS signal chain, including subsystems and the operational model along with the direction the signal chain will be going.

Title: The BRAND EVN Project in the IVS Context
Teachers:Gino Tuccari
Grade level:Beginners; new material.
Description:The BRAND wideband receiver is being developed with support from the European Union's Horizon 2020 research and innovation programme as a part of RadioNet. Its continuous frequency range from 1.5 GHz to 15 GHz makes it a scientifically extremely interesting development for radio astronomy. But it also covers the VGOS frequencies and even extends them to lower and higher frequencies. Used for geodesy, this could yield results superior to the ones which will be achieved with the traditional four VGOS bands. It will also allow to retrofit traditional prime focus antennas to become compatible with VGOS antennas in terms of frequency coverage, with a much greater output data rate. Another goal is to model an adequate feed for secondary focus; if successful, this would make the BRAND receivers usable for any VGOS antenna. The first half of the almost 4-year term of the project is over and it is possible to give an overview of the achievements so far and of what is planned for the near future.

Title: Introducing the FS Display Server
Teachers:David Horsley
Grade level:Beginners; new material.
Description:Have you ever lost scans by closing the wrong window at 4am? Do you sometimes want to run an observation from your laptop on the couch? Do you just think it would be cool to run the FS in a browser? Then this talk is for you! We will discuss the FS Display Server introduced experimentally in FS v9.13.0, which separates the display part of the Field System from the operational parts. We will demonstrate its features and explain how stations may enable it.