The BOW GNSS Receiver Project · GPS Technology Basics d As a first approximation, d is (Trx...
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The BOW GNSS Receiver Project Alex Morrow [email protected] Ziyi Lan [email protected] Franklin W. Olin College of Engineering October 28, 2015
Transcript of The BOW GNSS Receiver Project · GPS Technology Basics d As a first approximation, d is (Trx...
TheBOWGNSSReceiverProjectAlex Morrow [email protected] Lan [email protected] W. Olin College of EngineeringOctober 28, 2015
INTRODUCTIONTOGNSSCONCEPTS
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GNSS:GlobalNavigationSatelliteSystem
• A system employing satellites to provide global navigation information to users
• There are four GNSS systems• Galileo European Union (fully deployed 2020)• BEI‐DOU China• GLONASS Russia• GPS US
• We’ll describe GPS as an example of how GNSSs work
• The GPS system is divided into three segments• GPS Space Segment (SS): 24+ Satellites • GPS Control Segment (CS): 16 sites• GPS User Segment (US): Half the world’s population?
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GPS Receiver1. Determines time
it received message (Trx )
GPS Satellite orbit22 000 kilometers(14 000 miles)
Each satellite has a schedule for broadcasting messages containingSatellite identity, Time message transmitted (Ttx)Satellite’s precise location at Ttx
2. Uses satellite’s Ttx to determine distance d from receiver to satellite
GPS Technology Basics
dAs a firstapproximation, d is (Trx ‐ Ttx)*c
3 Combines d from at least 4 satellites to determine:
LatitudeLongitudeAltitude
Hubble and ISS orbits: ~400 kilometers(250 miles)
Six orbits, four satellites in a each
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THEBOWGNSSRECEIVERPROJECT
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Missing Link!
OpportunityFor BOWPresident’s Fund Project
$20K+Centimeter½ inch
$2KDecimeter6 inches
Existing GNSS Receiver Types in 2014
$20Ten meters30 feet
Surveying Self‐drivingtractors
Undergraduate Research
Find way home
Way too expensive
Too expensive
Inadequate Technology
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Accuracy
Price
Missing Link!
OpportunityFor BOWPresident’s Fund Project$20K+
Centimeter½ inch
$2KDecimeter6 inches
Existing GNSS Receiver Types in 2014
$20Ten meters30 feet
Surveying Self‐drivingtractors
Undergraduate Research
Find way home
$200Meter3 feet
BOW GNSS Receiver IdeaWay too expensive
Too expensive
Inadequate Technology
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Accuracy
Price
Just right
BOWGPSSReceiverGoals• Primary goal:
• Actual shared technology between BOW colleges• Education about shared technology (here you are!)
• GPSS Receiver Objectives:• Low Price (about $200 for whole receiver)• High Accuracy (looking for 1M accuracy)• Useful on all BOW campuses
• Easy to adapt to different project types• Makes new technology available as soon as possible
• Architectural design• Projects independent of GNSS technology changes
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BOWGNSSReceivertechnologysearchChosen for initial technology testing
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iPhone6 Ublox6 3DR$89
Ublox6P$214
Ublox7P$119
15m
3m1.8m
1.2m
Ublox m8n$69
4 constellation
0.6m
u‐blox GNSSchipinformalsanitytesting
Upward compatible programming interface
Informal accuracymeasurements
Quantity 1 prices
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GNSSReceiverApplicationOlin College Team Sailing ProjectNavigation system to let competitive blind sailors be more autonomous.
First on‐water BOW GNSS Receiver Test
Olin College Research Boat Sailing in Charles River Basin
August 14, 2015
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CooperationwithWellesley• Working with Prof. Katrin Monecke, Wellesley Department of GeosciencesGNSS Receiver appropriate for Bathymetric research
(How deep is the ocean?)
• Focus is for altitude (Z) accuracy• Harder than X/Y
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Nice to talk to you!Jason and Alex
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Bibliography
• GNSS Resources (EU)• www.navipedia.net
• GPS Resources (US)• www.gps.gov• Wikipedia/gps• Wikipedia/gps signals
• General Questions• StackExchange for GIS
• http://gis.stackexchange.com• u‐blox Corporation Resources
• https://www.u‐blox.com/en/positioning
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