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### VIE_GLOB

Hana Spicakova

VIE_GLOB_V1d

- compatible with VieVS Version 1d
- parameters which can be estimated

- from combination of more sessions

- station coordinates and velocities: TRF
- source coordinates: CRF
- Earth orientation parameters

-session-wise as reduced parameters

- zenith wet delay
- troposphere gradients
- Earth orientation parameters
- station and source coordinates (not suitable for global estimation)
- input data
- datum free N-matrices (ATPA) and b-vectors (ATPl)
- VieVS/DATA/LEVEL2
- created within a „normal“ run of VieVS

VieVS User Workshop 2011

VieVS/COMPILE/VIE_GLOB_V1d/vie_glob.m

Howtorun VIE_GLOBpath to the directory TEST_LEVEL2 with LEVEL2 data

INPUT

the subdirectory TEST_OUT will be created in VieVS/OUT/GLOB/_ESTIMATES

/_PLOTS

eventually in: /CRF

/TRF

OUTPUT

only sessions with a lower RMS than chosen (in this case RMS < 2) will be used in the global adjustment

if ticked, N matrices and b vectors with reduced parameters from each session will be saved into VieVS/OUT/GLOB/BACKWARD_DATA

VieVS User Workshop 2011

GUI for TRF

choose between NNT/NNR or NNT/ NNR /NNS

VieVS/DATA/GLOB/TRF/

the original VLBI-DISCONT.txt file is provided at the web site http://vlbi.geod.uni-bonn.de/IVS-AC/data/VLBI-DISCONT.txt

DISCONT/

DATUM/

VELOC/

REDUCE/

VELOC/TIES/

TRF_datum1.txt

const_velocity_8410.txt

test.txt

few_observations.txt

VieVS User Workshop 2011

special_handling_39.txt

GUI for CRFCRF_datum1.txt

VieVS/DATA/GLOB/CRF/

DATUM/

choose between NNR or NNR + translation in declination condition

REDUCE/

FIXED_SOURCES/

VieVS User Workshop 2011

Theoretical background

- Sort parameters in the N-matrix and b-vector
- Reduction of parameters
- always reduced: clock parameters, zwd and troposphere gradients
- can be reduced: EOP, stations and sources not suitable for global solution
- Stacking of the reduced normal equation systems

globally estimated p.

reduced p.

VieVS User Workshop 2011

Constraints

- zwd, troposphere gradients, EOP
- constraints are chosen in VIE_LSM
- station coordinates and velocities
- relative constraints for velocity
- same velocity for all coordinate intervals at one station (e.g. antenna repair)
- same velocity at stations in the same area (e.g. Hobart26 and Hobart12)
- datum definition
- source coordinates
- datum definition

VieVS User Workshop 2011

Datum definition

- Station coordinates and velocities
- NNT/NNR condition

constrained 12 parameters Helmert transformation

(3 translation and 3 rotation components + their time derivatives w.r.t. time)

- NNT/NNR/NNS condition

constrained 14 parameters Helmert transformation

(3 translation , 3 rotation components and 1scale component + their time derivatives w.r.t. time)

- Source coordinates
- NNR condition
- NNRcondition + 1 translation parameter

parameter dzaccouns for a global translationof the source coordinatesin declination, caused e.g. by inaccuracy of the tropospheric propagation correction for sources observed at low elevations) (Feissel-Vernier et al. (2006))

- fixing selected sources to a priori coordinates

VieVS User Workshop 2011

Final solution

- applying of the constraints
- final solution for global parameters
- estimates are stored as a structure array in Matlab format and as a txt file
- VieVS/OUT/GLOB/_ESTIMATES/TEST_OUT/
- globsol_TEST_LEVEL2.mat
- glob_results_TEST_LEVEL2.txt

VieVS User Workshop 2011

Estimates - Example

VieVS/OUT/GLOB/_ESTIMATES/TEST_OUT/glob_results_TEST_LEVEL2.txt

namesofsessions

numberofsessions

correctionstostation a priori coordinatesandtheirstandarddeviations [cm]

sessionswith RMS>maxRMS

epochofthecoordinates [mjd]

start, end [mjd] oftheinterval (time betweenbreaks)

correctionstostation a priori velocitiesandtheirstandarddeviations [cm/y]

stationswhichwereusedfor NNT/NNR

VieVS User Workshop 2011

Estimates - Example

estimatesof EOP:

dx, dy pole [mas]

dut1 [ms]

dX, dY [mas]

andtheirstandarddeviations

correctionstosource a priori coordinates (RA, De) andtheirstandarddeviations [mas]

VieVS User Workshop 2011

Results

this new TRF catalogue can be used as input catalogue in VieVS

„new catalogues“ (TRF and CRF) are created automatically in VieVS/OUT/GLOB/

TRF/TEST_OUT/trf_TEST_LEVEL2.txt

and

CRF/TEST_OUT/trf_TEST_LEVEL2.txt

VieVS User Workshop 2011

VieVS/OUT/GLOB/_PLOTS/TEST_OUT/

Plotsant_map_TEST_LEVEL2.eps

map of stations,

blue circles: station included in NNT/NNR

red circles: station excluded from NNT/NNR

stations in sessions included in the global adjustment

ant_activity_TEST_LEVEL2.eps

VieVS User Workshop 2011

Plots

VieVS/OUT/GLOB/_PLOTS/TEST_OUT/

sou_map_TEST_LEVEL2.eps

map of sources,

blue circles: source included in NNR

red circles: source excluded from NNR

sources in sessions included in the global adjustment

sou_activity_TEST_LEVEL2.eps

VieVS User Workshop 2011

Processing of a long time span of data (20 years or more)

- Problems
- if e.g. EOP would be considered as global parameters (stacking at the overlapping time steps), the final N matrix would be too huge – not possible to handle it at a normal PC
- position of some sources is not stable enough to handle it as a constant value
- unequal observation time at the stations – at some stations the observation interval is not sufficient to estimate reliable velocity

VieVS User Workshop 2011

Processing of a long time span of data (20 years or more)

- Problems
- if e.g. EOP would be considered as global parameters (stacking at the overlapping time steps), the final N matrix would be too huge – not possible to handle it at a normal PC
- position of some sources is not stable enough to handle it as a constant value
- unequal observation time at the stations – at some stations the observation interval is not sufficient to estimate reliable velocity

VieVS User Workshop 2011

Processing of a long time span of data (20 years or more)

- Problems
- if e.g. EOP would be considered as global parameters (stacking at the overlapping time steps), the final N matrix would be too huge – not possible to handle it at a normal PC
- position of some sources is not stable enough to handle it as a constant value
- unequal observation time at the stations – at some stations the observation interval is not sufficient to estimate reliable velocity

VieVS User Workshop 2011

Reduction

- In these cases the concerned parameters have to be excluded from the global adjustment by a session-wise reduction.
- The vector x2 we get from a so-called back solution for each session:
- Covariance matrix

After running VIE_GLOB we know the vector x1 (global parameters)

globally estimated p.

reduced p.

VieVS User Workshop 2011

Reduction

- If the button in the 1st GUI of VIE_GLOB is ticked, all needed parameters for a back solution will be stored in: VieVS/OUT/GLOB/BACKWARD_DATA/TEST_OUT/

i.e., N21, N22 and b2 for each session + some other information, e.g. description of the columns

- After finishing of VIE_GLOB run VieVS/OUT/GLOB/backward_solution.m
- in the source code you have to specify the name of the TEST_OUT and TEST_LEVEL2 directories and which reduced parameters you want to estimate
- The estimated values will be written into .txt files in VieVS/OUT/GLOB/BACKWARD_SOLUTION/TEST_OUT/ as
- ant_TEST_LEVEL2.txt
- eop_TEST_LEVEL2.txt
- sou_TEST_LEVEL2.txt
- tgr_TEST_LEVEL2.txt
- zwd_TEST_LEVEL2.txt

VieVS User Workshop 2011

Backwardsolution: zwd

The estimates for each station can be plotted with:

VieVS/OUT/GLOB/

plot_backward_zwd.m

VieVS User Workshop 2011

Backwardsolution: tgr

The estimates for each station can be plotted with:

VieVS/OUT/GLOB/

plot_backward_tgr.m

VieVS User Workshop 2011

Backwardsolution: EOP

The estimates for each EOP can be plotted with:

VieVS/OUT/GLOB/

plot_backward_eop.m

VieVS User Workshop 2011

Backwardsolution:antennacoordinates

The estimates for each station can be plotted with:

VieVS/OUT/GLOB/

plot_backward_ant.m

VieVS User Workshop 2011

Backwardsolution:sourcecoordinates

The estimates for each source can be plotted with:

VieVS/OUT/GLOB/

plot_backward_sou.m

VieVS User Workshop 2011

Thank you for your attention!

VieVS User Workshop 2011

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