Ground StationGround Stationfor Satellite Operationfor Satellite Operation

(CySat)(CySat)

May 10-07

Client: Matthew Nelson

Advisor: John Basart

Team: Karl Deakyne, SungHo Yoon, Luke Olson

Cyclone Satellite (CYSAT)

Project Plan Overall goal:

Ground Station for CySat Team Fick Observatory, Dish Antenna High sensitivity receiving Automatic Tracking

Previous Team: Dish control from computer Build 440 MHz Sub reflector Rotary Encoders for tracking dish

position

Our team: Ensure strength and signal to noise ratio

of received signal is adequate Tracking

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Requirements Functional

The system shall be able to receive a signal that is sent from an orbiting satellite with a sent power of 1W (or 3 dBm) and the signal should be easily recognizable by a standard radio located in the observatory

The system shall be able to automatically track an orbiting satellite

Non-FunctionalThe system shall fit inside the dishThe system shall be weatherproof

Project Plan

Work BreakdownLuke

○ Develop Tracking SoftwareSungHo, Karl

○ Design and Build Front-End

Schedule

Design – Front End

Calculations – Without modification

Analysis:Signal-to-Noise Ratio

= -109.11dBm – (-126.27dBm) = 8.68 dB (Input power) - (Sensitivity) = 6.99 dBmThese numbers do not yet meet the specifications!

Solution: Front-End Box for amplification

Received power at the satellite dish (worst case) -109.11dBm (by link budget)

Coax Cable (Belden 9913 (RG-8), 200ft) -5.8dB/200ft (Insertion Loss)Radio Input Power -114.91dBm Power of Radio Sensitivity (Standard Radio) -121.9dBm

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Design Front-End Progression

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First Full Parts Design

Design Front-End Progression

Design Before Purchasing Parts

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Band Pass Filter Problems with BPFs

Commercial filters not perfect for our range Custom filter not immediately available

SolutionsConsidered putting LPF and HPF in seriesAdvised advised to continue without BPFs, but

to leave room for eventual installation

EffectsRadio filters around center frequencyPre-filtering desirable, but not necessarySlight decrease in SNR, but this is negligible

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Design Front End Progression

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Final Design

Apr 2010

Design – Tracking Software

Requirement:Automatically track an orbiting satelliteSolution:

○ Pull azimuth and elevation from Ham Radio Deluxe

○ Track the position of the dish with existing rotary encoders

○ Move dish through an Ethernet connection with the motor control microcontroller

Design – Tracking Software

Implementation –Tracking Software Java Based Application

GUI○ Allows user to manually control dish, track a satellite,

and set calibration settingsData Monitoring

○ Two ThreadsDDEThread: Continuously pulls azimuth and elevation from

Ham Radio Deluxe, using Dynamic Data ExchangeDishPositionThread: Monitors the rotary encoders to track

the azimuth and elevation of the dish

Calibration○ Automatic Calibration to ensure accurate tracking

Implementation – Tracking Software

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Implementation – Front End

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Required Specifications

Filter Design Frequency, 440 MHz Filters out harmonics Low power

Switch Must work at 440 MHz, minimal

losses High Power Rating (~10W) Electrically controlled

Radio High Sensitivity Low Cost

Amplifier 440 MHz Low Noise Amplifier Low noise figure (<3) Moderate gain (~20dB)

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Device Specifications ZX60-33LN+ (LNA) Low noise Amplifier Low noise figure = 1.1 Gain = 21.3 dB @ 440MHz

881-CCR-33S6O (Switch) Loss at 440 MHz < .4 dB Power Rating at 440 MHz = 100W

CW Electrically controlled

Filter Too costly to get device within

specification

Radio Too costly for budget, the CySat

team will have to provide the radio Our Recommendation:

Icom 208H Sensitivity =

.18 uV, -37dBm Cost = $310

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Final Parts List

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Calculations – With Front-End

Analysis:Signal-to-Noise Ratio (at Satellite Dish)

= -109.11dBm – (-126.27dBm) = 17.16 dBPower into the Radio > Radio Sensitivity :

Radio is able to decode the input signal.

(Input power) - (Sensitivity) = 23.0 dBm

Power in process (440MHz)Received power at the satellite dish (worst case) -109.11dBm (by link budget)

System noise power -126.27dBm (by Noise Temperature)

Coax Cable (Carol® C1166(RG-8), 30ft) -2.76dB/30ft (Insertion Loss)LNA (ZX60-33LN+) 21dB (Gain)RF Switch (ZX80-DR230+), 3units -2.1dB (Insertion Loss)SMA to SMA adapter (SM-SM50+), 4units -0.12dB (Insertion Loss)Coax Cable (Belden 9913 (RG-8), 200ft) -5.8dB/200ft (Insertion Loss)Radio Input Power -98.9dBm Power of Radio Sensitivity -121.9dBm

Test Plan

Individual Part Testing Front-End Testing Tracking Software prototyping Overall System Evaluation and Testing

Test Place: SSCL Lab at Howe Hall Devices:

Signal Generator (Model: ) Spectral Analyzer (Model: ) DC Voltage Generator (Model: )

Methods: RF Switches

○ Apply 440MHz signal to the input of switch, using a signal generator.○ Change 0 DCV to 12 DCV supplied to switches.○ Observe if signal path is changed from “Normally Closed” to “Normally Open”.

Low Noise Amplifier (LNA)○ Apply 440MHz signal to LNA.○ Connect into spectral analyzer ○ Observe if the incoming signal is amplified as we expected.

Whole Front-End System○ Combine two methods above.

Checkpoints: if switches are working properly depending on voltage change. if the amplifier(LNA) is working properly as we expected.

RF Switch

LNA

Test Results

Switch 1  Normally Open (N.O.) Normally Closed (N.C.)  Frequency Power Frequency Power

0V Applied Noise -67dBm 440MHz 10.06dBm   

12V Applied 440MHz 10.05dBm Noise -66dBm

Switch 2  Normally Open (N.O.) Normally Closed (N.C.)  Frequency Power Frequency Power

0V Applied Noise -68dBm 440MHz 10.04dBm   

12V Applied 440MHz 10.06dBm Noise -67dBm

Switch 3  Normally Open (N.O.) Normally Closed (N.C.)  Frequency Power Frequency Power

0V Applied Noise -67dBm 440MHz 10.06dBm   

12V Applied 440MHz 10.05dBm Noise -66dBm

• Signal(440MHz): 10.26 dBm• Noise power: -50 ~ -80 dBm

Switch Test (Model: Mouser CCR-33SC-N)

Normally Open

Normally Closed

• Conclusion: Verified its switching operation

Test Results

Input Output

Center frequency: 440MHzMagnitude of Signal: -58.6dBm

Center frequency: 440MHzMagnitude of signal: -38.1dBm

• Experimental Gain: 20.5 dB• Expected Gain: 21.1 dB• Conclusion: Similar gain as expected

Low Noise Amplifier (Mini-circuits ZX60-33LN+)

Test Results Whole Front-End System

Testing Frequency: 439.9MHz Signal In: -39.9dBm Signal Out: -21.43dBm

Experimental Gain from the system: 18.47 dB Expected Gain: 16.01 dB

Analysis Better Gain than expected Gain Error reasoning:

Gain and loss in parts’ manual are less accurate for 440MHz.

Conclusion: The whole system is working as expected.

Prototyping/Testing – Tracking Software Ham Radio Deluxe Test

Prototyping/Testing – Tracking Software Motor Control Test

Tested with microcontroller

Evaluation of Overall System

IdeallyInstall sub reflectorInstall front-end boxInstall softwareTest entire system with orbiting satellitesTrain CySat on how to use the systemBut…

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Evaluation of Overall System

IssuesDuring winter the dish was frozen

○ Unable to do anything until MarchIn March we discovered that the dish does

not move up/downNumerous trips to the Fick Observatory to

attempt to fix issue failedRotary Encoders are only partially installed,

can’t install them until the dish moves downCan’t install sub reflector or front-end box

until dish can be moved down28

Conclusions

Implemented systems that we designed Unable to successfully implement final

product, due to unforeseen issues at the Fick Observatory

Future work:Fix issues at Fick Observatory

○ Motor Control○ Rotary Encoders

Install Sub-reflector, front-end box

Questions