vievs user workshop 14 – 16 september, 2011 vienna vie_glob hana spicakova

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VieVS User Workshop 14 – 16 September, 2011 Vienna VIE_GLOB Hana Spicakova

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VieVS User Workshop

14 – 16 September, 2011

Vienna

VIE_GLOB

Hana Spicakova

2VieVS User Workshop 2011

VIE_GLOB_V1d

compatible with VieVS Version 1d

parameters which can be estimated - from combination of more sessions

station coordinates and velocities: TRFsource coordinates: CRFEarth orientation parameters

- session-wise as reduced parameterszenith wet delaytroposphere gradientsEarth orientation parametersstation and source coordinates (not suitable for global estimation)

input datadatum free N-matrices (ATPA) and b-vectors (ATPl)VieVS/DATA/LEVEL2created within a „normal“ run of VieVS

VieVS User Workshop 2011 3

Last GUI in VIE_LSM

data for VIE_GLOB will be stored in DATA/LEVEL2/

VieVS User Workshop 2011 4

How to run VIE_GLOBVieVS/COMPILE/VIE_GLOB_V1d/vie_glob.m

path to the directory TEST_LEVEL2 with LEVEL2 data

the subdirectory TEST_OUT will be created in VieVS/OUT/GLOB/_ESTIMATES /_PLOTSeventually in: /CRF /TRF

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

cun

PvvT

0

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

INPUT

OUTPUT

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GUI for RF

Terrestrial Reference Frame

Celestial Reference Frame

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GUI for TRF

VieVS/DATA/GLOB/TRF/

DATUM/

REDUCE/

DISCONT/

VELOC/

VELOC/TIES/

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

TRF_datum1.txt

few_observations.txt

const_velocity_8410.txt test.txt

choose between NNT/NNR or NNT/ NNR /NNS

VieVS User Workshop 2011 7

GUI for CRF

VieVS/DATA/GLOB/CRF/

DATUM/

FIXED_SOURCES/ REDUCE/

choose between NNR or NNR + translation in declination condition

CRF_datum1.txt

test.txt special_handling_39.txt

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Theoretical background

Sort parameters in the N-matrix and b-vectorReduction of parameters

always reduced: clock parameters, zwd and troposphere gradientscan be reduced: EOP, stations and sources not suitable for global solution

Stacking of the reduced normal equation systems

2

1

2

1

2221

1211

b

b

x

x

NN

NN

globally estimated p.

reduced p.

211221211 NNNNNreduc

2122121 bNNbbreduc

nsereducreducreduc NNNN _2_1_ ...

nsereducreducreduc bbbb _2_1_ ...

9

Constraints

zwd, troposphere gradients, EOPconstraints are chosen in VIE_LSM

station coordinates and velocitiesrelative 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 coordinatesdatum definition

VieVS User Workshop 2011

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Datum definition

Station coordinates and velocitiesNNT/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 coordinatesNNR conditionNNR condition + 1 translation parameterparameter dz accouns for a global translation of the source coordinates in 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

11VieVS 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.matglob_results_TEST_LEVEL2.txt

0

T

B

BNN REDUCCREDUC wbb REDUC

CREDUC

REDUCCREDUC bNdx

11

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Estimates - Example

VieVS User Workshop 2011

VieVS/OUT/GLOB/_ESTIMATES/TEST_OUT/glob_results_TEST_LEVEL2.txtnames of sessions

number of sessionscorrections to station a priori coordinates and their standard deviations [cm]

corrections to station a priori velocities and their standard deviations [cm/y]

stations which were used for NNT/NNR

epoch of the coordinates [mjd]

start, end [mjd] of the interval (time between breaks)

sessions with RMS>maxRMS

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corrections to source a priori coordinates (RA, De) and their standard deviations [mas]

Estimates - Example

estimates of EOP:

dx, dy pole [mas]

dut1 [ms]

dX, dY [mas]

and their standard deviations

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Results

„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

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

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PlotsVieVS/OUT/GLOB/_PLOTS/TEST_OUT/

ant_activity_TEST_LEVEL2.eps

ant_map_TEST_LEVEL2.eps

stations in sessions included in the global adjustment

map of stations,

blue circles: station included in NNT/NNR

red circles: station excluded from NNT/NNR

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Plots

VieVS/OUT/GLOB/_PLOTS/TEST_OUT/

sou_activity_TEST_LEVEL2.eps

sou_map_TEST_LEVEL2.eps

sources in sessions included in the global adjustment

map of sources,

blue circles: source included in NNR

red circles: source excluded from NNR

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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

18

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

19

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

VieVS User Workshop 2011 20

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

Reduction

2

1

2

1

2221

1211

b

b

x

x

NN

NN

globally estimated p.

reduced p.

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

1211222

1222 xNNbNx

122121121

122

12222

NNQNNNQ

VieVS User Workshop 2011 21

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.min 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

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Backward solution: zwd

The estimates for each station can be plotted with:

VieVS/OUT/GLOB/plot_backward_zwd.m

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Backward solution: tgr

The estimates for each station can be plotted with:

VieVS/OUT/GLOB/plot_backward_tgr.m

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Backward solution: EOP

The estimates for each EOP can be plotted with:

VieVS/OUT/GLOB/plot_backward_eop.m

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Backward solution: antenna coordinates

The estimates for each station can be plotted with:

VieVS/OUT/GLOB/plot_backward_ant.m

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Backward solution: source coordinates

The estimates for each source can be plotted with:

VieVS/OUT/GLOB/plot_backward_sou.m

27VieVS User Workshop 2011

Thank you for your attention!