La Plata Ionospheric Model as a tool
for scientific and technological
applications
M. Gende1,2, C. Brunini1,2, F. Azpilicueta1,2
Universidad Nacional de La Plata, Argentina1
CONICET, Argentina 2
Outlook
LPIM model
SIRGAS-ION
Near real time data
LISN Project in Argentina
Conclusions and future work
2nd LISN Workshop. São José dos
Campos. November 2011
LPIM model
• Empirical
• Meteorological
• Total electron content
– Global
– Regional
– Local
2nd LISN Workshop. São José dos
Campos. November 2011
Data
• Ground GPS receivers (CORS)
• LEO GPS receivers
• Topex and Jason
2nd LISN Workshop. São José dos
Campos. November 2011
Observable
• Dual frequency zero difference (RINEX)
• L band
-40.3
STEC =
Nds
2 
f
2nd LISN Workshop. São José dos
Campos. November 2011
Observable
L4  L1  L2 =STEC + Br + Bs + N +
L4  STEC +  arc + 
• Even for the same satellite, two different arcs are generally affected
by different levelling errors
• IFB can be affected by significant intra-day variations.
• Levelling errors: 1.4 - 5.3 TECUs
.
•
Ciraolo L. et al. Calibration errors on experimental slant total electron content
determined with GPS. Journal of Geodesy, Springer, (81) 2, 111-120, DOI:
10.1007/s00190-006-0093-1, 2007.
2nd LISN Workshop. São José dos
Campos. November 2011
2D modelling
STEC
1

VTEC cos z '

 mh 
 mh  
VTEC (h,  )    alm cos  2
  bml sin  2
  Plm (sin  )
24 
24  


l 0 m0 
L
l
2nd LISN Workshop. São José dos
Campos. November 2011
MODIP
• A new coordinate for modelling the F2-layer and the topI
side ionosphere. Rawer (1984)
tan  
cos 
2nd LISN Workshop. São José dos
Campos. November 2011
Global model
CODE
•
•
UPC
LPIM
Azpilicueta F. et al. Global ionospheric maps from GPS observations using modip latitude’.
Advances in Space Research, DOI: jasr-d-04-01245, 2006.
Gende, M. et al. Inter comparison of total electron content maps for the South American region,
in International Union of Geodesy and Geophysics. 2007: Perugia, Italia.
2nd LISN Workshop. São José dos
Campos. November 2011
SIRGAS
• Starts as a geodetic project
• Now is also producing atmospheric
products
– Regional TEC maps
– Water vapor estimations
• Can share with LISN CORS GNSS data
• Generally not in real time
• http://www.sirgas.org/
2nd LISN Workshop. São José dos
Campos. November 2011
http://cplat.fcaglp.unlp.edu.ar
2nd LISN Workshop. São José dos
Campos. November 2011
2nd LISN Workshop. São José dos
Campos. November 2011
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Campos. November 2011
Tool to study climatologic conditions
•
Mosert, M. et al. Comparing IRI TEC prediction to GPS and digisond measurements at Ebro.
Advances in Space Research, 2007. 39(5): p. 841-847.
2nd LISN Workshop. São José dos
Campos. November 2011
Tool to study disturbed conditions
•
Sahai, Y. et al. Effects observed in the Latin American sector ionospheric F region during the intense
geomagnetic disturbances in the early part of November 2004. Journal of Geophysical Research
(Space Physics), 2009. 113(doi:10.1029/2007JA013007): p. 11.
2nd LISN Workshop. São José dos
Campos. November 2011
Applications in GNSS navigation
•
•
Gende, M. et al., Ionospheric biases correction for coordinates derived from GPS single point
positioning. Annals Of Geophysics, 2005. 48(3): p. 439-444.
Brunini, C. et al., Ionospheric Effects on Satellite Based Augmentation Systems (SBAS); WAAS, EGNOS,
GAGAN, MSAS and future systems. in Bacon Satellite Symposium. 2004. Trieste, Italia.
2nd LISN Workshop. São José dos
Campos. November 2011
Applications in geodetic
positioning
2nd LISN Workshop. São José dos
Campos. November 2011
•
Gende, M. et al. An ionospheric delay estimation technique to
improve large baseline L1 differential positioning. in Dynamic Planet.
IAG/IAPSO/IABO Joint Assembly. 2005. Cairns, Australia.
Near real time VTEC
• Stations with permanent Internet access.
• Five minutes double compress RINEX files
(30 seconds interval rate).
• Download central server using rsync.
• Process with a delay of 5 minutes.
• Run LPIM in local mode.
• NTRIP is not implemented yet.
2nd LISN Workshop. São José dos
Campos. November 2011
Corrientes
2nd LISN Workshop. São José dos
Campos. November 2011
Ingesting TOPEX data
vTEC
TP
vTEC
LPIM_GPS
vTEC
LPIM_GPS+TP
•
Bibbo, I., et al., Global vTEC Maps and instrumental DCB based on Combined GPS and TOPEX/Jason Measurements,
in Coupling, Energetics, and Dynamics of Atmospheric Regions (CEDAR) workshop 2010. 2010: University of
Colorado, Boulder, USA.
2nd LISN Workshop. São José dos
Campos. November 2011
3 D Modelling
•
Brunini, C. et al. Toward a SIRGAS service for mapping the ionosphere’s electron density
distribution. in Geodesy for Planet Earth. 2010. Buenos Aires: International Association of Geodesy.
2nd LISN Workshop. São José dos
Campos. November 2011
The actual state of the Argentinean
component of the LISN project
2nd LISN Workshop. São José dos
Campos. November 2011
2nd LISN Workshop. São José dos
Campos. November 2011
Problems
Intranet. No public and fix IP.
Internet interruptions.
Hard drives full.
Very low bandwidth.
Can not use the data for geodetic purpose.
2nd LISN Workshop. São José dos
Campos. November 2011
Conclusions and future works
 LPIM has more than a decade working as a tool
for ionospheric studies
 Is evolving towards a 4D model
 More physical equations are being implemented in
the program.
 More data are being assimilating (TOPEX-JASON,
LEO,…)
 Modifications must be done so the program works
as a filter and accepts NTRIP data
2nd LISN Workshop. São José dos
Campos. November 2011
2nd LISN Workshop. São José dos
Campos. November 2011
2nd LISN Workshop. São José dos
Campos. November 2011
2nd LISN Workshop. São José dos
Campos. November 2011