P18571: Sunspot Radio Telescope III

Subsystem Build & Test

Table of Contents

Team Vision for Subsystem Level Build & Test Phase

A 4 week plan was implemented for the team to work asymmetrically, playing on each team members strengths

The full list of deliverables and their statuses can be found here

Radio Technology Development

Three possible replacements for the feedhorn antenna have been obtained and measured on a network analyzer.

The original feedhorn was a Terk LOGTVO antenna. This antenna was broken and is in need of replacement. The standing wave ratio (SWR) is the most useful parameter for comparing these antennae.

public/Subsystem Build & Test Documents/antennas/LOGTVO_1.png public/Subsystem Build & Test Documents/antennas/terk_swr.png

The three tested antennas are as follows.

Magnavox MG-ANT-104

public/Subsystem Build & Test Documents/antennas/magnavox_mg-ant-104.jpg public/Subsystem Build & Test Documents/antennas/magnevox_swr.png

Boostwaves WA-2608

public/Subsystem Build & Test Documents/antennas/boostwaves_wa-2608.jpg public/Subsystem Build & Test Documents/antennas/wa-2608_swr.png

Boostwaves WA-2802

public/Subsystem Build & Test Documents/antennas/boostwaves_wa-2802.jpg public/Subsystem Build & Test Documents/antennas/wa-2802_swr.png

Based solely on the analyzer measurements, the Boostwaves antennas seem like good fits for replacements. The WA-2802 seems to have a slightly better response.

A test plan is developed to determine gain and beamwidth of the antennas using a transmitter and a dipole. It was attempted using the noise source that is part of the system calibration, but the noise was too low power to be detected by the receive antenna. A proper transmitter will be needed to conduct this experiment.

A full run down of the RF system was attempted, but it was discovered the the RF switch controlling which source the Callisto unit looked at did not work. A replacement is being found.

The TV antenna, ambient dipole, noise source, and 50 ohm load produce expected results when tested separately.

Software Development


The central SunTracker server/driver integrates the entire system and exposes an HTTP server for management and control. It currently is capable of exchanging messages with the Arduino, communicating with LABVIEW and ASCOM over HTTP/WebSockets, and generating status report and error email notifications.

The ASCOM driver has been adapted to communicate over WebSockets, however hardware testing is pending rewire.

Stack light communication/settings are not yet implemented pending design of the stack light and its protocol.

Controller Protocol

Server Protocol

Demo Server v1.0.1 (Windows x86_64)

Demo Server v1.0.2 (Source)

Screenshot of demo server running interactively. Includes disconnecting and reconnecting Arduino hardware controller.

public/Subsystem Build & Test Documents/software/serverDemo.png

Sun Tracking Algorithm

This Sun tracking algorithm is to replace the current program for calculating the suns current positon. The current solution does not provide autonomous tracking of the sun. With this algorithm, the positon can be calculated at regular intervals without the need for human intervention. To calculate the position, the python library PyEphem. The library is able to calculate key position data of many bodies in the sky, most importantly the sun. The type of data that can be calculated includes: Right Ascension, Declination, Azimuth and Altitude. This data can be used with the rest of the system to track the sun. Additionally, this library provides the Sunrise and Sunset times for the Calisto Scheduler.

Callisto Scheduler

The Callisto will capture data continuously. The scheduler will use the SunTracking code to calculate the rise and set times and save FIT files for all times during which an observation is scheduled. FIT files not associated with sun tracking or user observation will be discarded.


Arduino code was developed to receive wind data through an ADC. The captured voltages are then converted in to wind speed and transmitted through a serial connection. The integrity of measurements need to be verified, as the equation used to determine wind speed were taken from the data sheet. For now, this is assumed to be close enough for our purposes, as a thorough test of this component is not high priority.

LabVIEW FITS file reader system

public/Subsystem Build & Test Documents/Labview/FITSviewerv2.png

public/Detailed Design Documents/Software/Labview/FitsDemo2.PNG

Source VI and compiled executable

v2 version has been added, with the following additions:


LabVIEW 2013 32-bit runtime is required (free download) to run the executable if LabVIEW 2013 32-bit is not already installed. Source VI is available for recompilation. Debugging must be turned on for successful recompilation

VI will work in any 32-bit library, GFITSIO library ONLY works in 32-bit LabVIEW

To open the labview files successfully, the fits library must be installed in user.lib. The FITS library exists in the link below. 32 bit LabVIEW MUST be installed


JSON communication demo

public/Subsystem Build & Test Documents/Labview/LVside.PNG public/Subsystem Build & Test Documents/Labview/TerminalSide.PNG Source VI

To open the labview files successfully, the following libraries must be installed in via VI package manager. The links to the libraries are below.


/public/CAD/SRT/SRT The following is a summary of CAD work performed

Work to be done:

Risk and Problem Tracking

ID Category Risk Item Effect Cause Likelihood Severity Importance Action to Minimize Risk Owner
R1 Technical Improper feedhorn installation Feedhorn may have loose mounting or be unable to be assembled. Manufacturing Faults 0 3 0 Feedhorn to be replaced with Antenna ME
R2 Technical Unreliable internet connection to Zurich May not be able to transmit all data overnight. Environmental conditions including thunderstorms. 2 1 2 "Provide data backup until Zurich server confirms reception" CE
R3 Technical Dish may be too heavy for motors/actuators Tracking functionality is lost, manual repairs required Ice buildup, power depletion 1 2 2 Motors oversized for current load ME
R4 Technical File transfer system error Zurich server receives incomplete data Power lost or connectivity issues. 0 2 0 Create Temp file on FTP server, move when complete CE
R5 Technical Auto-calibration error Incorrect data analysis, manual repairs required Drift of control systems over time 2 3 6 2 callistos in parallel, one for cal one one for data CE
R6 Technical Network Communication Error Remote operation made difficult or impossible Loss of connectivity, internet outage 1 1 1 Ensure system doesnt rely on TeamViewer/Active user input CE
R7 Technical UPS battery dies System loses power and is no longer operational. Mains power is lost and UPS battery is exhausted. 1 2 2 Put system into safe shutdown state before battery is exhausted CE
R8 Technical RadioEyes/LabView incompatibility Additional time required for integration solution No documented API support 0 2 0 Plan B In effect:= custom Astronomical Data ME
R9 Technical Feedhorn selection may carry unexpected collaterals (integration) RX levels may become inefficient for extraction from raw signal Mismatching impedance and frequency response 1 3 3 Perform extensive testing on feed/dish assembly EE
R10 Technical Software Error Data may be corrupted or incorrect; Zurich may not recieve data at all Improper program setup / unforeseen program error 1 2 2 "Perform extensive software testing and provide data backup" CE
R11 Technical Interference between subsystems May cause errors or discrepencies in subsystem operation Improper magnetic shielding on power lines near vulnerable systems 1 2 2 "Isolate magnetic interference, or place wiring more carefully" EE
R12 Technical Improper power management One or more subsystems failing due to internal power loss Power delivery components insufficient to meet power needs 1 3 3 Perform extensive power system calculations EE
R13 Technical Internal subsystem overheating Damage to one or more subsystems Inadequate cooling systems or lack of temperature sensor 1 3 3 Test Plan for thermal model validation ME
R14 Technical UPS overheat Damage to battery system Temperature sensitive battery in harsh enviornment 0 3 0 Will install UPS indoors ME
R15 Resource Insufficient budget to meet all project requirements May need to take performance hits to accomodate cheaper budget Limited funds (~$500) 0 1 0 $1500 donation from ASRAS All
R16 Resource Destruction of Suntracker project hardware Loss of uniquely designed hardware, project delays Incorrect assumptions about input levels and tolerances/ general clumsiness 1 3 3 Observe best practices, be careful, stay away from other people All
R17 Resource Inadequate space to assemble and test Team may not be able to build project Specialized Test Requirements 1 3 3 Ensure that proper space or devices are reserved well in advance, only attempt finaly assy onsite. Prelimnary Assembly at RIT observatory. Wind and Thermal Testing All
R18 Resource Theft of system components Irreplaceable components may be lost Improper storage of materials 1 3 3 Lock physical project materials in a locker/keep at home All
R19 Resource Insufficient backup data storage Zurich or ASRAS server may fail to recieve data Insufficient or nonexistant backup data storage 0 2 0 Amount of data needed to exceed data capacity exceeds lifetime of system CE
R20 "Environmental/Social" Remote log-in to unit may pose security threat System may be tampered with by unauthorized user Malicious actor obtaining password/login information 1 3 3 Use Username/Password +Secure Design CE
R21 Technical IP66 may not be as advertized Water Damage Leak, improper sealing 1 3 3 Test current enclosure, use waterproof sealing ME
R22 Technical Software sends too many emails consecutively Flooded Mailbox Periodic Failure alerts 2 2 4 Batch alerts together, rate limit messages CE
R23 Technical Smarthost service unavailable System unable to send email alerts Service is unavailable 1 2 2 Alternate alert mechanism (stacklight) EE
R24 Technical Wind Damage System components break High winds, low structural integrity 1 3 3 Reinforce structure ME
R25 Technical System resonates with wind System components break Winds hitting natural frequencies of structure 1 3 3 Apply Damping ME
R26 Technical Heat Sensor Fails System overheats Random/Software Failure 1 2 2 Overkill on cooling solution/ Software safeguards ME
R27 Technical Humidity Sensor Fails Loss of humidity information, water damage Random/Software Failure 1 1 1 Enhanced waterproofing solution/ Software safeguards ME
R28 Technical Custom Astronomy Coordinate map unfeasible Unable to build necessary Radio Eyes Functionality ourselves Scope too large/Too complicated 2 2 4 Plan C: Track only the sun, deprecate Top40RF requirement ME
R29 Technical Improper Antenna Mount Impossible to get good reading Focal point miscalculation/ Design Change 1 3 3 Adjustable Antenna mount ME
R30 Technical Runaway Dish Damage to components Control/Electrical Failure, various 1 3 3 Install E stops EE
R31 Technical Shorts and Interference in unit System Malfunction, Potential Damage Improper Wiring 1 3 3 Rewiring, Robustification of system EE
R32 Technical Software Communication Error Hardware may not be controlled by PC software Software doesn't start, starts incorrectly 1 3 3 Arduino defaults into safe position if no PC contact CE
R33 Technical Improper Antenna installation Antenna may have loose mounting or be unable to be assembled. Manufacturing Faults 1 2 2 Utilize good practices ME
R34 Technical Dropped connection Lack of remote control To be investigated 3 3 9 Troubleshoot Error, robustify software ME/CE
R35 Resource Defective RF switch RF subsystem does not function ESD damage? 3 3 9 Purchase new switch EE

Risk Management Spreadsheet

Plans for next phase


Plans listed by individual

Brandon (CE)

Kyle (EE)

Slav (ME)

Dave (EE)

Plan for week 10 (Integrated System Build and Test)

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