Practical Applications for Environment and Agriculture in Rural Africa Session 4: GNSS implementation and uses in agriculture and environment United Nations/Zambia/ESA Regional Workshop on the Applications of Global Navigation Satellite System Technologies in Sub-Saharan Africa 26 June 2006, Lusaka, Zambia Presented on behalf of : Dave Doyle, Chief Geodetic Surveyor DOC National Oceanic and Atmospheric Administration, National Ocean Service National Geodetic Survey & Michael Rasher, National GPS Coordinator USDA Natural Resources Conservation Service National Cartography & Geospatial Center by Ken Alexander Senior Advisor National Space-Based PNT Coordination Office
Transcript
Practical Applications for Environment and Agriculture in Rural Africa
Session 4: GNSS implementation and uses in agriculture and environment
United Nations/Zambia/ESA Regional Workshop on the Applications of Global Navigation Satellite System Technologies
in Sub-Saharan Africa
26 June 2006, Lusaka, Zambia
Presented on behalf of :Dave Doyle, Chief Geodetic Surveyor
DOC National Oceanic and Atmospheric Administration, National Ocean Service National Geodetic Survey
&Michael Rasher, National GPS Coordinator
USDA Natural Resources Conservation Service National Cartography & Geospatial Center
byKen AlexanderSenior Advisor
National Space-Based PNT Coordination Office
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Geodetic Control
• Network of monumented points • Precisely measured in accordance
with standard procedures• Meets accuracy specifications • Adjusted to tie together and
documented for multiple uses
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Poured in place concrete post
Stainless steel rod driven to refusal
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Spatial Data Accuracy
Accuracy crucial to building useful Geodetic Information Systems (GISs)
GIS builders and users must understand: Impact of data accuracy Details of spatial data accuracy Spatial data accuracy needs
Surveying and mapping professionals should: Understand accuracy needs of users Be involved in data design and collection
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Why High Accuracy
• Realistic, useable representation of data – For local government, facilities management,
utility and other applications• Large scale applications can be conducted• Maps and decision making information
reliable• Data can be aligned and easily integrated• Survey data and GPS data can be input
directly• High accuracy data saves expense for many
operations
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Misperceptions about Accuracy
• Assumptions:– It will take care of itself– We’ll work on it later– The maps look good– The maps look accurate– We don’t really need that much accuracy– What we have is good enough– Just load whatever data we can get– It’s too expensive
• Too little attention and understanding
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Results of Inadequate Data Accuracy
• Data mismatches, inconsistencies, lack of registration
• Confusion
• Battling basemaps
• Wasted resources
• Decisions based on “bad” data
• Decisions based on in appropriate data
• Lawsuits
• Failed projects
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Autonomous Positioning: Before May 1, 2000
• L1C/A Code • Selective Availability On
25 - 100 m
Worst Case Horizontal 100 m1996 Federal Radionavigation PlanSection A2-1, Part Bhttp://www.navcen.uscg.mil/policy/frp1996
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Standalone Positioning Today
• L1C/A Code• No Selective Availability• Accuracy Improvement Initiative
~ 4 - 6 m
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Unaugmented Positioning: next decade
~ 1 – 3 m
Improved resistance to interference and availability
Standalone GPS, Galileo, GLONASS
Combined constellations to provide modest accuracy improvements?
• GPS data can be used to adjust other data– Can be used for survey control
• GPS = Accuracy
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Resource grade GPS Positioning:
~ 1 foot
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Large Area High Accuracy Differential Reference System
ACCURATE: cm accuracy on a global scale• MULTIPURPOSE: Best Support for: Geodesy,
Geophysics, Surveying, Navigation, Mapping, Charting and other GIS activities
• ACTIVE: Accessible through Continuously Operating Reference Stations (CORS) and other post processed (derived) products
• INTEGRATED -- Support International services and standards (e.g. International Earth Rotation Service, International GPS Service etc.)
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Continuously Operating Reference Stations (CORS)
Installed and operated by diverse, Federal, State, International and local Agencies
-NOAA/National Geodetic Survey
-NOAA/OAR Forecast Systems Lab
-U.S. Coast Guard - DGPS/NDGPS
-Corps of Engineers - DGPS
-FAA - WAAS/LAAS (Future)
-State DOTs
-County and City
-Academia
-Private Companies
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Continuously Operating Reference Stations (CORS)
Variety of “Geodetic Quality” Dual-Frequency
Receivers and Antennas are available
Manufacturers include:
Allen-Osborne
Ashtech/Thales
Leica
Trimble
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•Receiver/Antenna at least dual frequency (L1 and L2)
•Very stable mounting•Reliable power available•Provider has on-site Internet access•Secured location
•Approximate cost ~ $30 – 50k each
CORS Requirements
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Continuously Operating Reference Stations (CORS)
• International Terrestrial Reference Plane Coordinates
• Network data collection - Hourly & Daily• Daily 3D Network Integrity Adjustment• Public Data Distribution - Internet• (http://www.ngs.noaa.gov/CORS/cors-data.html)• 11 Year
NGS Provides:• Global On-Line Data Holding
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International GNSS Service Tracking Network
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Not Operational
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What is OPUS?• NGS On-Line Positioning User
Service
• Processes GPS data
• Global availability (masked)
• 3 goals:
– Simplicity
– Consistency
– Reliability
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http://www.ngs.noaa.gov/OPUS
You’ve got mail!
OPUS solution
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Unaugmented GPS for Agriculture and
Environment
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Locating and Recording Locating and Recording Natural and Cultural Features Natural and Cultural Features
for Local and Regional for Local and Regional PlanningPlanning
Village in Ghana
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Wild FruitWild Fruit Burkina FasoBurkina Faso
Processing MangoProcessing Mango GuineaGuinea
Children Planting TreesChildren Planting Trees GhanaGhana
Improved GranaryImproved Granary UgandaUganda
Food Security and ReforestationFood Security and Reforestation
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Dam ImprovementDam Improvement MadagascarMadagascar
Solar Panels for Water PumpsSolar Panels for Water Pumps NigerNiger
Pond ConstructionPond Construction CameroonCameroon
Purifying WaterPurifying Water CameroonCameroon
Developing, Protecting, and Ensuring Water SuppliesDeveloping, Protecting, and Ensuring Water Supplies
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Preparing, Monitoring, and Managing WildfiresPreparing, Monitoring, and Managing Wildfires
29UN Workshop Zambia27 June 2006Protecting and Managing Wildlife and Habitats Protecting and Managing Wildlife and Habitats
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Global Positioning SystemPractical Applications for Agriculture and Environment
in Rural Africa
“We must feed our people, have safe drinking water, treat the
ill ...transportation, exports and other things will come in time. “
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Sunset in Zambia
At the end of the Day…
Change can occur with GPS
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Contact Information
Ken Alexander, Senior AdvisorNational Space-Based PNT Coordination Office
Herbert C. Hoover Bldg., Rm. 68221401 Constitution Avenue, NW
