VieVS User Workshop 14 – 16 September, 2011 Vienna External Ionospheric Files Claudia Tierno Ros
VieVS User Workshop
14 – 16 September, 2011
Vienna
External Ionospheric Files
Claudia Tierno Ros
VieVS User Workshop 2011 2
Introduction
VLBI S-Band + X-Band 2.3 GHz 8.4 GHz
IonosphericCorrection*
Fragment from VLBI observation file (NGS file)
* Ionospheric delay depends on number of free electrons along ray path
VieVS User Workshop 2011 3
Introduction
Problem!!
Sometimes not possible to observe in two frequencies
Solution:
Use of external ionospheric file!!
4VieVS User Workshop 2011
External Ionospheric Files
GNSS TEC maps
↓
IGS / CODE GIMs
Based on Single Layer Model
Latitude/Longitude resolution of 2.5/5°
Temporal resolution 2 hours
Accuracy 2 to 8 TECU
VieVS User Workshop 2011 5
External Ionospheric Files
Fragment from external ionospheric file
VieVS User Workshop 2011 6
Example1. Start VieVS
Process the session you want as usual
VieVS User Workshop 2011 7
Example2. Start program
C:\Vievs\ION\PROGRAM\GUI\start_createExtIonoFilesGUI.m
VieVS User Workshop 2011 8
Example3. Select session and GIM
VieVS User Workshop 2011 9
Example
We obtain this message
The GIM has been downloaded from IGS/CODE serverC:\Vievs\ION\MAPS\[IGS/CODE]\[year]
VieVS User Workshop 2011 10
Example4. Unzip GIM
C:\Vievs\ION\MAPS\[IGS/CODE]\[year]
If the VLBI observations took place in more than one day, 2 maps will be downloaded
VieVS User Workshop 2011 11
Example5. Re-run program
C:\Vievs\ION\PROGRAM\GUI\start_createExtIonoFilesGUI.m
VieVS User Workshop 2011 12
Example
We obtain this message
The ionospheric File has been created!C:\Vievs\ION\[directory chosen]
VieVS User Workshop 2011 13
Example6. Start VieVS
7. Select session
VieVS User Workshop 2011 14
Example8. Select external file
VieVS User Workshop 2011 15
Example9. Continue as usual
VieVS User Workshop 2011 16