Ongo 2-COngo 2-CRadio TelescopeRadio Telescope

Greg BonettLaura Janvrin

Project Advisor:John Basart

Ali AbdelsalamOsman Abdelsalam

Project GoalProject Goal

Develop a working radio telescope for Iowa Develop a working radio telescope for Iowa State, thus increasing research State, thus increasing research opportunities for students and faculty on opportunities for students and faculty on campus, especially in the Physics and campus, especially in the Physics and Astronomy DepartmentAstronomy Department

Concept SketchConcept Sketch

(carries radio signal)

System Block DiagramSystem Block Diagram

Start of Year StatusStart of Year Status

Wiring issues on tower prevented operation of coaxial switch, noise source, and inhibited data collection

Limit Switch Relay board was not functioning properly, which prevented movement of the dish

Positioning software did not include tracking over time, and raster scan was inefficient

No documentation existed for limit switch relay board or terminal blocks within interface box

DeliverablesDeliverables

New Interface Box with permanent PCBs capable of reliable operation without frequent maintenance

Functional Tracking and Raster Scan software Functioning positioning feedback, basic

calibration routines, basic positioning correction Limit Switch circuitry to stop motors when limits

are reached Complete, useful documentation

Operating EnvironmentOperating Environment

Ambient temperatures range from -20Ambient temperatures range from -20ºF – ºF – 110ºF110ºF

Strong wind, snow, ice, and rainStrong wind, snow, ice, and rain Vulnerable to lightningVulnerable to lightning

Project RisksProject Risks

Dish hardware is custom built for our observatory, Dish hardware is custom built for our observatory, and cannot be replaced if broken.and cannot be replaced if broken.

Outdoor hardware can withstand temperature Outdoor hardware can withstand temperature extremes, but there is a potential for ice buildup to extremes, but there is a potential for ice buildup to prevent telescope operation.prevent telescope operation.

Much of the existing hardware is old and prone to Much of the existing hardware is old and prone to breaking down, much of the wiring is unreliable.breaking down, much of the wiring is unreliable.

As this project has moved to a phased approach, As this project has moved to a phased approach, critical information about the system could be lost critical information about the system could be lost if the new group and the returning group do not if the new group and the returning group do not work together.work together.

Risk ManagementRisk Management Maintenance must be performed each semester Maintenance must be performed each semester

to make sure all of the telescope hardware is to make sure all of the telescope hardware is working.working.

Outdoor work on the telescope was all performed Outdoor work on the telescope was all performed when the weather allowed.when the weather allowed.

The team has been replacing old cables and The team has been replacing old cables and resealing weatherproof boxes to ensure reliability resealing weatherproof boxes to ensure reliability of equipment.of equipment.

In both the fall and spring, returning members In both the fall and spring, returning members worked with new members to help share worked with new members to help share knowledge of the entire system.knowledge of the entire system.

System ComponentsSystem Components

Positioning SpecificationsPositioning Specifications Reported dish position shall be accurate to within Reported dish position shall be accurate to within

0.1 degrees for both azimuth and elevation.0.1 degrees for both azimuth and elevation. Azimuth and Elevation calibration shall be Azimuth and Elevation calibration shall be

performed automatically or through a very simple performed automatically or through a very simple (one or two step) process.(one or two step) process.

Continuous position updating shall allow tracking Continuous position updating shall allow tracking of objects and performing raster scans.of objects and performing raster scans.

PositioningPositioningThis semester, the team focused on characterizing the positioning This semester, the team focused on characterizing the positioning

capabilities of the telescope and began calibrating the positioning.capabilities of the telescope and began calibrating the positioning.Preliminary characterization and calibration was accomplished by Preliminary characterization and calibration was accomplished by

aiming the dish at sun and comparing positioning feedback to the aiming the dish at sun and comparing positioning feedback to the known coordinates of the sun.known coordinates of the sun.

Interface Box SpecificationsInterface Box Specifications Interface Box shall be properly labelled to allow Interface Box shall be properly labelled to allow

ease of troubleshooting and maintenance.ease of troubleshooting and maintenance. Interface Box shall allow connection between the Interface Box shall allow connection between the

computer’s data acquisition card, and the receiver, computer’s data acquisition card, and the receiver, limit switch circuit, coaxial switch actuation, and limit switch circuit, coaxial switch actuation, and motor control box.motor control box.

Interface Box circuitry shall be solid state Interface Box circuitry shall be solid state components mounted on a printed circuit board.components mounted on a printed circuit board.

Interface Box documentation shall include Interface Box documentation shall include schematics for all circuits, as well as details for all schematics for all circuits, as well as details for all wiring connections.wiring connections.

Interface Box – Limit Switch Interface Box – Limit Switch CircuitryCircuitry

In the fall, a PCB layout was designed based on the In the fall, a PCB layout was designed based on the current limit switch relay board, but re-examination this current limit switch relay board, but re-examination this semester revealed missing connections. semester revealed missing connections.

A much simpler circuit was designed and tested that A much simpler circuit was designed and tested that performs the required functions.performs the required functions.

The new circuit was created using a PCB, which will The new circuit was created using a PCB, which will improve reliability of the limit switch circuitry.improve reliability of the limit switch circuitry.

Interface Box – Positioning Interface Box – Positioning CircuitCircuit

Positioning circuit includes new Limit Switch circuit as Positioning circuit includes new Limit Switch circuit as well as a voltage divider circuit for positioning well as a voltage divider circuit for positioning feedbackfeedback

Interface Box – Positioning PCB Interface Box – Positioning PCB LayoutLayout

Interface Box – Power RelayInterface Box – Power Relay An existing power relay circuit was modified and An existing power relay circuit was modified and

installed into the interface box, and software was installed into the interface box, and software was modified to allow the relay to be tripped remotely.modified to allow the relay to be tripped remotely.

With the relay installed, all components of the With the relay installed, all components of the interface box can be controlled using a Remote interface box can be controlled using a Remote Desktop connection.Desktop connection.

Interface Box – Voltage Interface Box – Voltage Regulator PCBRegulator PCB

Voltage Regulator circuit maintains a constant voltage Voltage Regulator circuit maintains a constant voltage in the Interface Boxin the Interface Box

Interface Box – Coax Switch Interface Box – Coax Switch Relay PCBRelay PCB

Coax Switch Relay circuit grounds the antenna when Coax Switch Relay circuit grounds the antenna when the switch is activated via software or physically. the switch is activated via software or physically.

It also powers the LNA, mixer, and noise source, and It also powers the LNA, mixer, and noise source, and can switch on the receiver.can switch on the receiver.

Interface Box – New BoxInterface Box – New Box

The new rack-mounted The new rack-mounted box will be neat and box will be neat and organized.organized.

PCB boards will replace PCB boards will replace existing boards.existing boards.

Ribbon cables and new Ribbon cables and new connectors will be used connectors will be used to make the box reliable to make the box reliable

Old Interface Box

New Interface Box

Software SpecificationsSoftware Specifications

Software shall support all system, component, and Software shall support all system, component, and user interface specifications.user interface specifications.

Software must possess an efficient raster scan Software must possess an efficient raster scan function.function.

Software must be able to track celestial objects over Software must be able to track celestial objects over time.time.

Software shall be organized according to semester Software shall be organized according to semester and frequently backed up to prevent loss of work.and frequently backed up to prevent loss of work.

Software documentation shall allow future team Software documentation shall allow future team members to pick up where previous team left off.members to pick up where previous team left off.

Software – Raster ScanSoftware – Raster Scan Old Raster Scan software in LabVIEW was modified Old Raster Scan software in LabVIEW was modified

to eliminate unnecessary and time-consuming motion to eliminate unnecessary and time-consuming motion of the telescope dish.of the telescope dish.

Software – Software – Raster Scan User InterfaceRaster Scan User Interface

Software – Software Limits for Software – Software Limits for Dish Movement Dish Movement

Only allow opposite voltage to pass to Motor Control Only allow opposite voltage to pass to Motor Control Box when dish is 2 degrees from each physical limitBox when dish is 2 degrees from each physical limit

Software - WikiSoftware - Wiki

To facilitate the passing of knowledge from semester To facilitate the passing of knowledge from semester to semester, the team has implemented a Wiki. to semester, the team has implemented a Wiki.

Existing documentation was uploaded to the Wiki and Existing documentation was uploaded to the Wiki and indexed on the Wiki. This will also allow team indexed on the Wiki. This will also allow team members to search through all the documentation members to search through all the documentation contained on the Wiki for needed information.contained on the Wiki for needed information.

The wiki can be accessed at: The wiki can be accessed at: www.sscl.iastate.edu/wiki/www.sscl.iastate.edu/wiki/

Complete System Complete System SpecificationsSpecifications

System shall be operable remotely.System shall be operable remotely.Software shall be comprehensible to Software shall be comprehensible to

astronomy students.astronomy students.System equipment shall not require System equipment shall not require

maintenance more than twice per semester.maintenance more than twice per semester.

System MaintenanceSystem Maintenance In the fall, the team replaced faulty cable and conduit going up to the dish.In the fall, the team replaced faulty cable and conduit going up to the dish. A weather-proof seal was added to the feedhorn cap to prevent water from leaking in.A weather-proof seal was added to the feedhorn cap to prevent water from leaking in. Feedhorn was checked in the spring for water.Feedhorn was checked in the spring for water.

Testing AreasTesting Areas

RF Section – All components relating to radio RF Section – All components relating to radio signals (feedhorn, amplifier, mixer, coaxial line)signals (feedhorn, amplifier, mixer, coaxial line)

Positioning Hardware – Detection equipment Positioning Hardware – Detection equipment and motorsand motors

Positioning Software – Software programs used Positioning Software – Software programs used to position the dish for data acquisitionto position the dish for data acquisition

Interface Hardware – All circuitry used to Interface Hardware – All circuitry used to connect the computer to the other system connect the computer to the other system componentscomponents

Testing ObjectivesTesting Objectives

Confirm basic operation of all componentsConfirm basic operation of all componentsIndividual electrical componentsIndividual electrical componentsRF SectionRF SectionPositioning hardwarePositioning hardwarePositioning softwarePositioning softwareInterface hardwareInterface hardware

Quantify system parametersQuantify system parametersMeasure RF lossesMeasure RF lossesDetermine positioning accuracyDetermine positioning accuracy

Testing – RF SectionTesting – RF Section

Noise Source off

Individual RF components in the front-end box (mixer, LNA, noise source) were tested using a signal generator and spectrum analyzer

The entire signal path was tested using a signal generator at the observatory

Testing - RF SectionTesting - RF Section

Measured appropriate gain/loss through the Measured appropriate gain/loss through the entire system and through the front-end entire system and through the front-end componentscomponents

Testing – RF SectionTesting – RF Section

Component Gain/loss

Low-noise amplifier 28 dB

Converter 19 dB

Noise source 10 dB

Testing - Positioning HardwareTesting - Positioning Hardware

Confirmed dish will move to known degree Confirmed dish will move to known degree limitslimits

Verified position detection hardware is accurateVerified position detection hardware is accurateAfter calibration, software (without software limits in After calibration, software (without software limits in

place) shows 0° for minimum elevation, 86.5° for place) shows 0° for minimum elevation, 86.5° for maximum elevation, etc.maximum elevation, etc.

Verified that position output is preciseVerified that position output is precisePositioning variation is less than 0.05 degree if dish Positioning variation is less than 0.05 degree if dish

is not movingis not moving

Testing - Positioning SoftwareTesting - Positioning SoftwareConfirmed software function by measuring Confirmed software function by measuring

DAQ outputDAQ outputVerified functionality by running positioning Verified functionality by running positioning

software software Input coordinates of known source (the sun)Input coordinates of known source (the sun)Positioning software with correction placed dish in Positioning software with correction placed dish in

proper position proper position

Verified tracking software functionality Verified tracking software functionality Verified raster scan software functionality by Verified raster scan software functionality by

performing raster scan of area of sky including performing raster scan of area of sky including the sunthe sun

Testing – Intensity GraphTesting – Intensity Graph Tested the intensity graphing capabilities of our systemTested the intensity graphing capabilities of our system

Performed a manual scan across the sun and recorded Performed a manual scan across the sun and recorded the intensity every 10 msthe intensity every 10 ms

Amplitude of 385 corresponds to a solar flux value of 490000 Jansky

Testing - Interface HardwareTesting - Interface Hardware

Performed continuity checks to ensure Performed continuity checks to ensure components are properly connectedcomponents are properly connected

Confirmed all software programs properly Confirmed all software programs properly activate appropriate hardware relaysactivate appropriate hardware relays

Verified input and output voltages meet Verified input and output voltages meet component specificationscomponent specifications

Work DescriptionsWork Descriptions

Green = Task Complete Yellow = Task In Progress

End of Semester StatusEnd of Semester Status

We are testing the new Interface Box. All three new PCBs in the Interface Box have

been installed. Raster Scan and Tracking software have been

tested. The RF system has been extensively tested and

recommendations made for repairs. All relevant interface box circuitry and positioning

circuitry has been documented and labelled.

Earned Value AnalysisEarned Value Analysis The old Interface box has been causing problems since

its creation. The new box will reduce the amount of maintenance required.

The preliminary positioning calibration done this semester will give future teams a basis for more precise calibration and correction.

Documentation that has been created will improve future teams’ abilities to familiarize themselves with the project quickly and solve problems faster.

For the Next TeamFor the Next Team

Now that the basic software is available and working, unified user interface software should be written to make the system more user-friendly.

Pointing correction software can be written to further calibrate the positioning of the telescope.

The impedance of the feed horn should be matched to the line.

The raster scan software should be modified to do successive scans to reduce image noise.

Lessons LearnedLessons Learned Conscious effort needs to be made to stay on

schedule. Proper documentation saves time and work in the

long run. It is impossible to plan all tasks at the beginning

and work through them – problems will always arise and require adjustments and new planning.

ConclusionsConclusions The new Interface Box will be a great benefit to future

teams in terms of reliability and ease of understanding.

The intensity of the sun has been successfully measured, and all components of the RF system have been characterized.

All of the software needed to run the telescope is complete, but improvements can still be made in terms of making one unified program.

At the end of this semester, the radio telescope system will be operational for future teams to add additional astronomy features.

AcknowledgementsAcknowledgements Dr. John Basart for work as advisor Dr. Gregory Smith for feedback and providing

funds for parts Matt Nelson for help with PCB ordering Jesse Griggs and Matt Clausman for Eagle

software training Ryan Cragg for help with making a lid for the

Motor Control Box