THE INFLUENCE OF SPACE WEATHER ON HIGH PRECISION POSITIONING IN THE NORDIC REGION Bo Jonsson
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Transcript of THE INFLUENCE OF SPACE WEATHER ON HIGH PRECISION POSITIONING IN THE NORDIC REGION Bo Jonsson
THE INFLUENCE OF SPACE WEATHER ON HIGH PRECISION POSITIONING IN THE NORDIC REGION
Bo Jonsson
Lantmäteriet, National Land Survey of Sweden
www.swepos.com
Co-authors:
Gunnar Hedling, Lantmäteriet
Jan Johansson, Chalmers university of Technology
Contents
• Surveying techniques - overview
• Sunspot maximum 1989
• Sunspot maximum 2000
• Next sunspot maximum - expectations
Surveying before GPS
Surveying using GPS (1)
Regional Positioning Service
0,5 - 5 centimeter
Surveying using GPS (2)
SWEPOS™ - a Swedish network of reference stations
SWEPOS control centre in Gävle
Position
PositionTailor made
RTK data
Reference-station data
NordNSydS SydM SydN
Other GPS applications
Measurements at sea, Picture; Marin mätteknik Machine guidance, Picture; PEAB
Swedish Maritime Administration
Agricultural applications
Sunspot Maximum 1989 (1)
Conditions:
• Few GPS-receivers (<20)
• Single frequency receivers
• Primitive receiver technology
• Only post-processing
• Short baselines (<10 -20 km)
Sunspot maximum 1989 (2)
Impacts: • Some days difficulties to get “fixed solutions”
Solutions:• Shorter baselines if possible• Re-measurement another day
Forecast of geomagnetic activities from Geological Survey of Canada
Sunspot maximum (2000)
Conditions: • GPS had been introduced in the Surveying community (larger number of receivers )
• Both post-processing and real-time positioning• Dual-frequency receivers • More advanced receivers• Pilot projects for Network-RTK
Sunspot maximum 2000 (2)
Impacts: • Some days difficulties to get “fixed
solutions” both for post-processing and real-time
• “False” fixed solutions
Solutions:• Shorter baselines if possible• Re-measurement next day
Estimation of Ionospheric index I95 at SWEPOS control center
•
Ionosphere Activity Autumn 2003 (1)
Oct-Nov 2003 Max Planetary Index and EPN ambiguity resolution percentage
0
20
40
60
80
100
Date
Per
cen
t an
d 1
0xP
l in
dex
Serie1
Serie2
Ionosphere Autumn 2003 (2)
• 28 October and 4 November 2003 enormous flares were ejected by the sun.• The 28 October flare made it impossible to measure with Network RTK for 2 days in Sweden!• The 4 November flare only caused small disturbances in Sweden!
Forecast of geomagnetic activities from Geological Survey of Canada
Pre-study Network-RTK Projects 2000-2001 (Positioning Service)
Position Stockholm Mälaren (Jan-May 2001)• Users from Governmental Agencies and Local Authorities• GPSnet and Cellular phone (GSM)Result:• Very promising• Prototype Production Networks should be established
New-RTK
SKAN-RTK
Stock-Mäl
Sunspot maximum 2000 (3)
The last sunspot maximum didn’t stop the development of Network RTK because:• It was rather mild.• Network RTK proved itself to be a robust technique!• The I95 Index was built into GPSNet!• Many available Space Weather websites.
The next sunspot maximum 2011?
• Improved signal processing in the user equipment?
• Increased number of satellite signals (GLONASS, L2C, L5)?
• SWEPOS provides ionospheric index I95 in real time to the users via SWEPOS web-site
• A reliable space weather forecast service for high precision positioning using GNSS should be beneficial?
Space weather forecast service for the next sunspot maximum 2011
• The best model of a Space Weather forecast is of course a standard weather forecast.• The length of a magnetic storm is very important – a couple of hours to days• The user shall get the information day by day if he can expect a successful GNSS positioning before he start his work in the field
• To have some hint about this would be most useful.
Conclusion
One important issue for high precision positioning applications using GNSS techniques during the next sunspot maximum period is a reliable Space Weather Forecast Service which tells the user day by day if he can expect a successful GNSS positioning
Many thanks
for your
attention!