Senior Design ProjectsNational Radio Astronomy Observatory

Richard Prestage, John Ford, Mark WhiteheadRandy McCullough, Jason Ray, Tim Weadon

2.3 acre collecting area

485 ft

At 100 m, the GBT is the largest fully steerable telescopein the world.

305 ft

The Advantage of Unblocked OpticsDynamic Range

Near sidelobes reduced by a factor >10 from conventional antennas

Gain & SensitivityThe 100 meter diameter GBT performs better than a 120 meter conventional antenna

Reduced Interference

Characteristics of the GBT

Large Collecting AreaSensitive to Low Surface Brightness

Sky Coverage & Tracking (>85%)Angular ResolutionFrequency CoverageRadio Quiet ZoneUnblocked Aperture

state-of-art receivers & detectorsmodern control softwareflexible scheduling

A telescope for cosmologyThe origin and destiny of the Universe

Studying black holes and extreme environments to determine the fate and age of the Universe

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A telescope for cosmologyThe origin and destiny of the Universe

Measuring Sunyaev-Zel'dovich effect to determine the size and scale of galactic origins

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A telescope for fundamental physics

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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 EnhancedWe 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 EnhancedDigital signal processing

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Pushing the state of the art in bandwidth and resolution

Green Bank FPGA lab building digital signal processing hardware

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A Telescope Designed to be EnhancedSoftware EngineeringAdvancing 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

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• We are keen to start a number of 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 four here.

• One project will involve computer science and development only.

• Three projects are more cross-disciplinary within electronic engineering.

The Projects

• A new Engineering Graphical User Interface for the GBT.

• Design and implementation of a new “artificial pulsar” instrument test fixture.

• Design of a series of daughterboards for the standard GBT microcontroller

• GBT Active surface control system upgrade.

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WVU Senior Capstone Project –New Engineering Graphical User Interface

Mark WhiteheadGreen Bank Software Development Division

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CLEO

CLEO 12-18 GHz Dual Feed Receiver

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CLEO Future

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CLEO is a great application!

It is also 15 YO Tcl/Tk application and needs to be maintained by SDD which already maintains a large base of C++ and Python code. Either SDD learns Tcl or we port...

CLEO Future

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CLEO relies on an interface to the rest of the system which has grown increasingly difficult to maintain – we would like to remove that dependency.

The rest of the system has been recently modified to use ‘data streaming’ technology and we would like to explore upgrading CLEO to use that.

WVU Senior Capstone Project

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We propose porting CLEO to C++/Python as a Senior Capstone project.

This is a software engineering project and is best suited for CS students who may be interested in pursuing professional software development.

We recommend managing the project using an Agile Methodology (viz., Scrum) with weekly iterations. Pivotal Tracker would be used to manage stories and track velocity.

The GB SDD Division Head will be the “Scrum Master” and responsible for overall management.

The original developer, an NRAO Astronomer with a successful track record and genuine interest in working with students, would be the “Product Owner” and responsible for feature and usability requirements.

The GB SDD would specify the technology requirements (e.g. programming language, high-level architecture).

WVU Senior Capstone Project

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The student team would be responsible for design, implementation, testing and documentation of the Device Explorer application.

WVU Senior Capstone Project

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This effort may involve modifications to the core monitor and control system or the development of re-usable CLEO infrastructure libraries. Information describing the core monitor and control system will be provided by GB SDD.

The primary result of this effort should include a working Device Explorer application with useful documentation. If Device Explorer is delivered before the end of the allotted time, work on the next highest priority CLEO application to port could begin.

It is also desirable to produce a short paper, suitable for submission to the SPIE Astronomical Telescopes and Instrumentation conference, summarizing the overall concept, specific software issues encountered during development and results.

WVU Senior Capstone Project –Artificial Pulsar Test Fixture

Randy McCulloughHead of GBT Digital Electronics Groups

Wideband Artificial Pulsar

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• The GBT operates extremely sophisticated digital backends to support pulsar search and pulsar timing projects.

• Custom instrumentation designed in-house and in collaboration with university partners using the “CASPER” DSP toolset.

• Telescope time is extremely precious, so we need to test offline as far as possible.

• Need a test fixture which closely approximates the natural characteristics of an actual pulsar.

• In particular, the pulse period (in msec range) and pulse dispersion through the interstellar medium.

Pulsar Frequency versus pulse phase

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Project Description

• It’s currently envisioned that this design will be based upon a suitably chosen PIC uController made by Microchip and programmed in C (or other suitable uController); used in conjunction with a number of RF components such as wide band noise sources, digitally controlled band pass filters, summing amplifiers, attenuators, etc.

• Candidate(s) are expected to fully define the target functionalities and performance parameters by conducting initial research through internet searches, consultations with pulsar astronomers, discussions with RF and digital engineers, etc.

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Development of draft Operator’s Manual

• A basic description of the Wideband Artificial Pulsar Instrument

• Target specifications• Theory of operation with block diagram(s)• Proposed schematics and/or wiring diagrams• Basic outline of proposed software design• Proposed packaging arrangement including operator

controls, connectors, etc.• List of operator-adjustable parameters along with their

adjustment ranges, etc.• Preliminary Bill of Materials • Also: a proposed project schedule, estimated manpower

requirements, and estimated parts costs.

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Preliminary Design Review

• Project team members will present the documents referred to above to a panel of reviewers comprised of pulsar astronomers, RF and digital engineers, etc.

• The outcome of this PDR will be a set of revisions to be made to the draft Operator’s Manual, a revised schedule, along with revised estimates of manpower requirements and parts costs.

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Design and Construction

• At this point, the team will begin work in conjunction with RF and digital engineers, lab technicians, and pulsar astronomers to carry out the design, development, construction, programming, testing, and documentation of the Wideband Artificial Pulsar Instrument.

• Design, engineering, and testing tools which may be utilized throughout this project include:– Autodesk Inventor (packaging and mechanical design)– 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– Digital Multimeter

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Successful Completion

• The final step in completion of this project will be a technical seminar lasting between 15 and 30 minutes to be given before a general audience during which a summary of the project will be offered through the use of PowerPoint slides or similar presentation tool(s).

• Project performance metrics will include: achievement of desired specifications, adherence to projected schedule(s), resource containment including manpower utilized and overall final parts costs, quality and user-friendliness of documentation, etc.

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WVU Senior Capstone Project –Daughterboards for standard GBT µC

Tim WeadonGreen Bank Telescope Digital Engineer

GBT microcontroller upgrades

• The NRAO has designed a small computer card with Ethernet, I2C, SPI, and 3.3 volt logic I/O capabilities.

• The computer is a Netburner MOD 5270 with a Motorola ColdFire 5271 uProcessor.

• The NRAO computer is a “Motherboard” that has a Xilinx Spartan 3AN FPGA which allows the designer to interface the ColdFire to a wide range of “Daughterboard” designs.

• The NRAO-Green Bank Servo group needs various daughterboard designs to upgrade various subsystems on the Green Bank telescope.

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Required Expertize

• • Real-Time Software Design, Integration and Testing• • Hardware design• • Printed Circuit Board Schematic Capture (Using

EAGLE Graphical Layout Editor).• • Interfacing to standard industry hardware interfaces

(SPI, I2C, ColdFire 5271 Busses)• • XILINX FPGA programming (Interfacing a Spartan

3AN with the ColdFire 5271 and daughterboard peripheral chips).

• • Conforming to an NRAO design specification protocol between the FPGA and the ColdFire 5271 and the external daughterboard bus.

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Technical Details• It is assumed that various daughterboards will stack on

the motherboard through a 50 pin connector. Each daughterboard provides one or more of the functions listed below: – Interface to various Magnetostrictive linear

transducers. (A minimum of 6 per board)– Provide an A/D with a minimum of 16 input channels

with at least 16 bit resolution.– Provide a D/A with a minimum of 8 channels with at

least 12 bit resolution.– Provide a Synchro/Resolver-to-Digital Converter with

at least 12 bit resolution.• Each design shall be compatible with the NRAO design

requirements such that multiple daughterboards will be able to be mounted on one motherboard and function simultaneously. Each board will be able to be read from/written to every millisecond and provide the required resolution. 31

Team Responsibilities• Each project team will be responsible for hardware, software

(C++) and firmware (VHDL) designs and will deliver an end product that meets the project requirements. In particular each team will:– Given the appropriate documents and background

information, will write a requirements document and get it approved by the NRAO before proceeding to the next stage of the project.

– Choose the components, design the circuits, oversee the production of the PCB and other necessary hardware.

– Write a software design document for the system and application code on the MOD 5270 uProcessor.

– Write a firmware design for the Xilinx FPGA VHDL firmware.

– Write the necessary Interface documents (detailing the communication on or between the MOD 5270, FPGA, and all busses used.)

– Write a test plan, with procedures, and demonstrate the final product to the customer. (NRAO or Advisor)

– Provide a bill of materials, in spreadsheet form.

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Motherboard

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Example Daughterboard

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RS-485 (Position Encoder Interface) Card

WVU Senior Capstone Project –Active Surface Controller Upgrade

Jason RayGreen 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.

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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.

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Existing Hardware• The actuator assembly consists of a small DC motor for

movement up or down, and an LVDT for position sensing.

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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:– Planning the project– Gathering and defining the requirements– Designing the hardware and software– Participating in a design review– Writing the software– 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).

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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 (not necessarily based on the H-bridge device) 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.

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Deliverables

The deliverables from this project include:• Project plan and schedule• Hardware design of the control modules• Software and firmware designs for the control modules• Control system design• Prototype system to demonstrate the control of 16

actuators.• Presentation of results including a demonstration of

hardware• Complete documentation of the system, including:

– Drawings– Schematics– PCB layout and fabrication files– Source code for all software and firmware

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