Senior Design Projects National Radio Astronomy Observatory Richard Prestage, Jason Ray, Justin Richmond-Decker, Vereese van Tonder

2.3 acre collecting area 485 ft At 100 m, the GBT is the largest fully steerable telescope in the world. 305 ft

The Advantage of Unblocked Optics Dynamic Range Near sidelobes reduced by a factor >10 from conventional antennas Gain & Sensitivity The 100 meter diameter GBT performs better than a 120 meter conventional antenna Reduced Interference Characteristics of the GBT Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage Radio Quiet Zone Unblocked Aperture state-of-art receivers & detectors modern control software flexible scheduling

A telescope for cosmology The origin and destiny of the Universe Studying black holes and extreme environments to determine the fate and age of the Universe 4

A telescope for fundamental physics 5 The fastest pulsars test our understanding of matter at the most extreme densities Timing of pulsars gives the most stringent tests of theories of gravity Kramer et al 2006 Science

A Telescope Designed to be Enhanced We have an ongoing development program to ensure the GBT remains a vibrant, cutting-edge instrument for years to come All development is done in conjunction with college & university groups around the country

A Telescope Designed to be Enhanced Digital signal processing 7 Pushing the state of the art in bandwidth and resolution Green Bank FPGA lab building digital signal processing hardware

8 A Telescope Designed to be Enhanced Software Engineering Advancing astronomical software through technologies, visualization, and high performance computing Upcoming data rate of >10Pb/day; Take advantage of web-based technologies e.g. GWT, AJAX, JAVA, Genshi

NRAO / WVU Senior Design Projects 9 We are keen to continue joint-supervised NRAO / WVU Senior Design Projects. Students would be co-supervised by a WVU faculty member and an NRAO staff member. We have a range of projects available; we will highlight three here. One project will involve computer science and development only. Two projects are more cross-disciplinary within electronic engineering.

The Projects GBT Active surface control system upgrade Design and implementation of a new “artificial pulsar” instrument test fixture A data streaming upgrade for the GBT 10

WVU Senior Capstone Project – Active Surface Controller Upgrade Jason Ray Green Bank Telescope Digital Engineer

GBT Active Surface The GBT is so large that the shape of the primary reflector changes over elevation, mainly due to gravity. To correct this problem, the GBT has an active surface comprised of 2209 actuator assemblies, which can adjust the 2004 surface panels as needed to bring the surface back to the required parabolic shape. The hardware components for this system were originally procured starting in early 1992, now making them over 20 years old, and at this point obsolete. Given the importance of the active surface for high frequency observing, the control system should be upgraded with modern hardware, software, and communications protocols. 12

Existing Hardware The current system is based on three MV167 VME computers, with custom VME IIOP (Intelligent Input Output Processor) boards, which communicate with the H-Drive modules and LVDT modules. The H-Drive modules allow for bidirectional on/off control of 16 actuators each. The LVDT modules are analog input modules that can monitor 16 LVDT position sensors each. 13

Existing Hardware The actuator assembly consists of a small DC motor for movement up or down, and an LVDT for position sensing. 14

Upgrade Project The scope of this project will be to design and develop an upgraded and modernized control system for the GBT Active Surface. Tasks will include: – Picking up where the previous group left off – Planning the project – Gathering and defining the requirements – Designing the hardware, software, and control system – Testing and documentation of the finished device The VME computers and IO cards shall be replaced by a modern computer running Linux Redhat 64. The proprietary IIOP interface, for communicating between the computer and the control modules, shall be replaced by a standard, ethernet based interface (i.e., telnet). 15

Upgrade Project The H-Drive and LVDT modules shall be replaced by microcontroller based modules that will provide control/monitor for 16 actuators each. The current H-Drive modules only allow for simple “on/off” control of the motors. It is desirable for the new motor control module to have a higher quality control mechanism, such as pulse width modulation (PWM). The new control system hardware, software, and communications protocols shall all have wide commercial acceptance in order to stave off obsolescence for as long as possible. The hardware components shall be highly reliable and readily available from standard parts suppliers. 16

Work Experience This project offers the opportunity to gain valuable, real-world work experience in the following areas: – Project planning – Electronics circuit design – Printed circuit board design – Control systems design – Embedded firmware design – Software design – Mechanical packaging & RFI mitigation design – Hardware construction, troubleshooting, & testing 17

Current Status This year’s group has: – Developed test circuit boards to use for the control system design. – Successfully implemented control of a single actuator using a microcontroller development kit and a prototype PCB. – Completed the design for the module adapter boards required to interface the new control modules to the existing wiring. This next steps include: – Expanding their design to control 16 actuators in a single module pair. – Develop the circuit boards needed to implement this design – Mechanical packaging of the module into an RFI enclosure – Documentation 18

Project Information WVU project team – Dr. Parviz Famouri – WVU supervisor – Jeffrey Smith – Charles Taylor – Gregory Thurston NRAO Supervisor – Jason Ray – – (304) Project documentation – 19

WVU Senior Capstone Project – Wideband Artificial Pulsar Vereese Van Tonder, Digital Engineer Randy McCullough, Head of GBT Digital Electronics Group

Wideband Artificial Pulsar 21 WBAP

Pulsar Properties Emulate pulsars with ms periods Emulate pulsar frequency dispersion through ISM Higher frequency components arrive first 22

WBAP Project Overview 23 An extended project Research & documentation – Set target specifications – Project schedule – Bill of materials – SW & HW design proposals Design review by multidisciplinary panel Design implementation and verification – SW development (C coding) – Board layout using Eagle PCB – Various SW packages

WBAP System Overview MHz – 1000 MHz Command line interface Variables – Pulse amplitude, width, period – Pulse polarization

WBAP System Requirements 25 Emulate ISM use dispersive TL

Required Interests & Outcomes Work within a multidisciplinary environment – Pulsar astronomers – SW, RF, and digital engineers Integrating system components Various SW packages will be used: – Autodesk Inventor for instrument packaging – Eagle PCB (schematic capture and Printed Circuit Board Layout) – Microwave Office (RF/Microwave design, modelling, etc.) – Vector Network Analyzer – Portable Spectrum Analyzer – Portable Digital Oscilloscope 26

Software Development at NRAO Justin Richmond-Decker Green Bank Software Development Division

Develop and support software for scientific achievement What Do We Do?

Programming Methodology Agile programming Shared code Free software Git revision control

Sensitive, low-noise observing platform Expandable and upgradable Minimal interdependencies Allow experts to use all hardware capabilities Allow novices to think about astronomy, not devices A laboratory of instruments, not a black box Design Goals

M&C system is the GBT’s software backbone (C++) Interface with telescope’s hardware/firmware YGOR, GB, GBT Managers Parameters / Samplers Monitor and Control

GBT Signal Path Frontend Backend

FITS Files VEGAS Antenna Weather FITS sdfits SDFITS Pipeline Managers store data in FITS format

ASTRID Astronomer’s Integrated Desktop Written in Python Monitor/Control observations Edit and validate observing scripts Real-time (or offline) data display GBT Status display Command console, logs

ASTRID Observation Management

ASTRID Data Display

ASTRID GBT Status

FPGA Programming Many backends (signal processing) use FPGAs Firmware controls circuit behavior Can easily load/reload different firmware Software reads and writes to FPGA Versatile behavior using identical hardware/software

FPGA Firmware

Some Projects I’ve Worked On 40 Monitor and Control – CalibLamp_3mm Manager – Rotator Manager – RA_Mark5 Manager Astrid – Data display updates – GBT Status upgrade

Potential WVU Senior Capstone Project Data Streaming – Using ØMQ – Any number of applications can receive this data – Currently can only monitor telescope – Want to implement control

Thank you for your attention! For more information, contact: Richard Prestage Natalia Schmid 42