1. HG contribution to the GRC and more
Dzana Horozovic
Retreat 2019
Hohe Wand, May 2019

2. Current activity Galileo Reference Center
H2020 Call managed by the GSA (GRC – MS Consortium)
WP 3.4: NeQuick G performance
Aim of the WP: To study and analyze the performance of the NeQuick G ionospheric model in different latitudinal regions
Comparison to the GPS Klobuchar model
Evaluation based on data from stations in three latitude regions
WP Technical coordination:
Norvegian Mapping Authority
NMA NO
WP Participants:
TU Wien (Tech University of Vienna)
TUV AT
University of Porto
FCUP PT
Space Research Centre, Polish Academy of Sciences
SRC/CBK PL
Hohe Wand, May 2019

3. Galileo Reference Center
High latitudes (above 55° north)
Central European latitudes
Azores and equatorial region
Hohe Wand, May 2019

4. NeQuick G at TUW – Analysis chain
Calculate TEC values for each pair station-satellite
Load input data:
Extract Galileo ionospheric corrections from header of navigation files (a0, a1, a2)
Get station positions w.r.t. ITRF2014
Get satellite positions w.r.t. ITRF2014
Get month, time of day (UTC)
Interpolate TEC over grid for mid-lat region
Write IONEX file
Plot VTEC map
Plot VTEC difference map (w.r.t. CODE)
TEC comparison
Site specific range differences (m)
Site specific residual iono slant error (TECU)
Compute TEC values from observations 2 1 3 4
Hohe Wand, May 2019

5. TUW regional (TUWR) - overview
Network: 35 permanent ground stations
Start DoY: 274 (2018)
Grid size: 0.5°x 0.5°
Coverage: +30° to +65° lat, -15° to +45° lon
Temporal resolution: 1h (25 maps in file)
Observation type: geometry-free zero- difference code and carrier phase
Sat.system: GPS+Galileo
Integrated electron density: Described by spherical harmonics (up to degree 6)
Post-processing mode
Hohe Wand, May 2019

6. TUW regional (TUWR) – Mapping function
MSLM (Modified Single-Layer Model)
All free electrons are concentrated in a shell of infinitesimal thickness at an effective height H (height of maximum electron density at the F2 peak and ranges from 350 km to 450 km.
𝑭 𝑰 𝒛 = 𝑬 𝑬 𝑽 = 𝟏 𝒄𝒐𝒔 𝒛′
𝒔𝒊𝒏 𝒛′ = 𝑹 𝑹+𝑯 𝒔𝒊𝒏 𝜶𝒛 𝑤ℎ𝑒𝑟𝑒
𝑧, 𝑧 ′ …𝑧𝑒𝑛𝑖𝑡ℎ 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒𝑠 𝑎𝑡 𝑡ℎ𝑒 ℎ𝑒𝑖𝑔ℎ𝑡𝑠 𝑜𝑓
𝑡ℎ𝑒 𝑠𝑡𝑎𝑡𝑖𝑜𝑛 𝑎𝑛𝑑 𝑜𝑓 𝑡ℎ𝑒 𝑠𝑖𝑛𝑔𝑙𝑒 𝑙𝑎𝑦𝑒𝑟
𝑅……𝑚𝑒𝑎𝑛 𝑅𝑎𝑑𝑖𝑢𝑠 𝑜𝑓 𝑡ℎ𝑒 𝐸𝑎𝑟𝑡ℎ 𝐻……ℎ𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑠𝑖𝑛𝑔𝑙𝑒 𝑙𝑎𝑦𝑒𝑟 𝑎𝑏𝑜𝑣𝑒
𝑡ℎ𝑒 𝐸𝑎𝑟𝑡 ℎ ′ 𝑠 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 (450 km) 𝛼……𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑖𝑜𝑛 𝑓𝑎𝑐𝑡𝑜𝑟
Single-layer model
Hohe Wand, May 2019

7. TUW regional (TUWR) - LC
Geometry-free linear combination (L4) 𝑳 𝟒 =−𝒂 𝟏 𝒇 𝟏 𝟐 − 𝟏 𝒇 𝟐 𝟐 𝑭 𝑰 𝒛 𝑬 𝜷,𝒔 + 𝑩 𝟒 𝑷 𝟒 =+𝒂 𝟏 𝒇 𝟏 𝟐 − 𝟏 𝒇 𝟐 𝟐 𝑭 𝑰 𝒛 𝑬 𝜷,𝒔 + 𝒃 𝟒 𝑤ℎ𝑒𝑟𝑒 𝐿 4 , 𝑃 4 ……………….𝑔𝑒𝑜𝑚𝑒𝑡𝑟𝑦−𝑓𝑟𝑒𝑒 𝑝ℎ𝑎𝑠𝑒 𝑎𝑛𝑑 𝑐𝑜𝑑𝑒 𝑜𝑏𝑠𝑒𝑟𝑣𝑎𝑏𝑙𝑒𝑠 (𝑖𝑛 𝑚𝑒𝑡𝑒𝑟𝑠) 𝑓 1 , 𝑓 2 ……………….𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑖𝑒𝑠 𝑎𝑠𝑠𝑜𝑐𝑖𝑎𝑡𝑒𝑑 𝑤𝑖𝑡ℎ 𝑡ℎ𝑒 𝑐𝑎𝑟𝑟𝑖𝑒𝑟𝑠 𝐿 1 𝑎𝑛𝑑 𝐿 2 𝑎……………………𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 (=4.03∗ 𝑚𝑠 −2 𝑇𝐸𝐶𝑈 −1 ) 𝐹 𝐼 𝑧 ……………….𝑚𝑎𝑝𝑝𝑖𝑛𝑔 𝑓𝑢𝑛𝑐𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝑧𝑒𝑛𝑖𝑡ℎ 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑧′ 𝐸 𝛽,𝑠 …………….𝑣𝑒𝑟𝑡𝑖𝑐𝑎𝑙 𝑇𝐸𝐶 𝑖𝑛 𝑇𝐸𝐶𝑈 𝑎𝑠 𝑎 𝑓𝑢𝑛𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑔𝑒𝑜𝑔𝑟𝑎𝑝ℎ𝑖𝑐 𝑜𝑟 𝑔𝑒𝑜𝑚𝑎𝑔𝑛𝑒𝑡𝑖𝑐 𝑙𝑎𝑡𝑖𝑡𝑢𝑑𝑒 𝛽 𝑎𝑛𝑑 𝑠𝑢𝑛−𝑓𝑖𝑥𝑒𝑑 𝑙𝑜𝑛𝑔𝑖𝑡𝑢𝑑𝑒 𝑠 𝐵 4 = 𝜆 1 𝐵 1 − 𝜆 2 𝐵 2 ..𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 𝑏𝑖𝑎𝑠 𝑖𝑛 𝑚𝑒𝑡𝑒𝑟𝑠 𝑑𝑢𝑒 𝑡𝑜 𝑡ℎ𝑒 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑝ℎ𝑎𝑠𝑒 𝑎𝑚𝑏𝑖𝑔𝑢𝑖𝑡𝑖𝑒𝑠 𝐵 1 𝑎𝑛𝑑 𝐵 2 𝑤𝑖𝑡ℎ 𝑡ℎ𝑒 𝑐𝑜𝑟𝑟𝑒𝑠𝑝𝑜𝑛𝑑𝑖𝑛𝑔 𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ𝑠 𝜆 1 𝑎𝑛𝑑 𝜆 2
Hohe Wand, May 2019

8. Results delivered to GRC
Daily VTEC maps for Central Europe
Daily VTEC difference maps for Central Europe w.r.t CODE
Daily site specific range difference plots
Daily site specific residual IONO Slant Error plots
Quarterly reports
Deliverables being uploaded to BKG database
Hohe Wand, May 2019

9. Results delivered to GRC (1) - Maps
DoY 318/2018
(TUWR)
DoY 318/2018
(NEQG)
Hohe Wand, May 2019

10. Results delivered to GRC (2) – Diff.maps
DoY 318/2018
(TUWR)
DoY 318/2018
(Klobuchar)
Differences w.r.t. CODE:
TUWR up to 2 TECU
NeQuick G up to 5 TECU
Klobuchar up to 10 TECU
DoY 318/2018
(NEQG)
Hohe Wand, May 2019

11. Results delivered to GRC (3,4)
Sites for validation:
NICO °-40° lat
AJAC
GRAS °-50° lat
LEOP
JOZ °-55° lat
Hohe Wand, May 2019

12. Results delivered to GRC (3) – Range difference (L1+model w. r
Results delivered to GRC (3) – Range difference (L1+model w.r.t ionosphere-free LC, DoY 318/2018)
Hohe Wand, May 2019

13. Results delivered to GRC (3) – Statistics
Daily mean range difference residuals for all validation sites and all elevation angles
Hohe Wand, May 2019

14. Results delivered to GRC (4) – IONO slant error
Specification defined by the project
Hohe Wand, May 2019

15. Results delivered to GRC (4) – IONO slant error
Hohe Wand, May 2019

16. Results delivered to GRC (4) – Statistics
Daily mean percentage of epochs outside the NEQG specification (Jan-Mar 2019)
Hohe Wand, May 2019

17. Other activities GEOWEB (March 2016 – October 2018)
Final Meeting, Tirana, Albania, October 2018
GNSS (GPS+Galileo) based ERP estimation + Tidal coefficients estimation
EGU 2018 (April) – dataset Feb-Jul 2017 (6 months)
INTERGEO 2018 (October) – dataset Jul-Dec 2017 (6 months)
Hohe Wand, May 2019

18. Other activities
Determination of High Frequency Earth Rotation Parameters utilizing GPS + Galileo observation data (presented at Intergeo 2018)
Polar motion time series (July 2017-Dec. 2017) w.r.t. IERS2010
GPS/GAL Differences up to 0.5mas (Std: +/-0.2 mas)
GPS Differences up to 1mas (Std: +/-0.28 mas)
Some remaining signals in series
Hohe Wand, May 2019

19. Other activities
Determination of High Frequency Earth Rotation Parameters utilizing GPS + Galileo observation data (presented at Intergeo 2018)
LOD time series (July 2017-Dec. 2017) – raw LOD
Hohe Wand, May 2019

20. Other activities
Determination of High Frequency Earth Rotation Parameters utilizing GPS + Galileo observation data (presented at Intergeo 2018)
Corrections to the IERS2010 Model for the 10 main tides up to:
16 μas derived from GPS+Galileo series
23 μas derived from GPS series
X-pole residual amplitudes
GPS/Galileo – IERS2010 and GPS - IERS
Hohe Wand, May 2019

21. Ionospheric modelling
Future plans
Continue the work on ERP estimation  improve solution
2 parameter types to incorporate in PhD work:
ERPs
Ionospheric modelling
Based on
Global network
2 solutions:
GPS+Galileo
GPS only
Based on
Regional network
Hohe Wand, May 2019

22. Future plans
Compare two different solutions in order to study the improvement provided by Galileo (if existing) - so far, ERP comparisons showed a visible improvement when using the combined solution, but longer timeseries are definitely needed
Encourage multi-GNSS users to include more GPS+Galileo combined solutions
Write PhD related article in a journal paper in the near future
Hohe Wand, May 2019

23. Thank you for your attention!
Hohe Wand, May 2019