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