Post on 21-Dec-2015
VieVS User Workshop
14 – 16 September, 2011
Vienna
VIE_SIM
Jing SUN, Andrea PANY
2VieVS User Workshop 2011
Why simulations?
generate artificial delay observables – useful to test
new scheduling strategies
different station network geometries
antenna specifications
...
VieVS User Workshop 2011 3
generate artificial delay observables – useful to test
new scheduling strategies
different station network geometries
antenna specifications
...
generate zero input NGS files – useful to test the impact of different models in the analysis
Why simulations?
4VieVS User Workshop 2011
What is simulated?
o-c = (zwd2·mf(el2) + clk2) – (zwd1·mf(el1) + clk1) + wnbsl
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What is simulated?station 2 station 1
o-c = (zwd2·mf(el2) + clk2) – (zwd1·mf(el1) + clk1) + wnbsl
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What is simulated?
zwd - troposphere zenith wet delay
provided by a turbulence simulator
based on the approach by Nilsson et al. (2007)accounts for spatial and temporal correlations
station 2 station 1
o-c = (zwd2·mf(el2) + clk2) – (zwd1·mf(el1) + clk1) + wnbsl
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What is simulated?
mf(el) - mapping function (elevation)
station 2 station 1
zenith
mapping function
o-c = (zwd2·mf(el2) + clk2) – (zwd1·mf(el1) + clk1) + wnbsl
you should use thesame mf for the creationof the simulated files andfor the processing of thesimulated data – unlessyou want to study mf errors
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What is simulated?
clk - station clock
simulated as sum of a random walk andan integrated random walk process
according to Herring et al. 1990
station 2 station 1
o-c = (zwd2·mf(el2) + clk2) – (zwd1·mf(el1) + clk1) + wnbsl
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What is simulated?
wnbsl - white noise per baseline
station 2 station 1
o-c = (zwd2·mf(el2) + clk2) – (zwd1·mf(el1) + clk1) + wnbsl
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VIE_INIT
VIE_MOD
VIE_SIM
VieVS and VIE_SIM
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VIE_INIT
VIE_MOD
VIE_SIM
VieVS and VIE_SIM
artif
icia
l
NGS file
s
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VIE_INIT
VIE_MOD
VIE_SIM
VIE_INIT
VIE_MOD
VIE_LSM
VieVS and VIE_SIM
artif
icia
l
NGS file
s
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Data flow in VIE_SIM
vie_sim
scanantenna
simparamparamfile
INPUT
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Data flow in VIE_SIM
INPUT az, el and mjd are extracted and sorted by station
vie_sim
scanantenna
simparamparamfile
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Data flow in VIE_SIM
sim_swd
sim_clk
sim_wn
INPUT az, el and mjd are extracted and sorted by station
vie_sim
scanantenna
simparamparamfile
16VieVS User Workshop 2011
Data flow in VIE_SIM
sim_swd
sim_clk
sim_wn
vie_sim
INPUT az, el and mjd are extracted and sorted by station
group delays are formed and stored scanwise
scanantenna
simparamparamfile
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Data flow in VIE_SIM
sim_swd
sim_clk
sim_wn
vievs2ngs
vie_sim
INPUT az, el and mjd are extracted and sorted by station
group delays are formed and stored scanwise
scanantenna
simparamparamfile
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Data flow in VIE_SIM
sim_swd
sim_clk
sim_wn
vievs2ngs
vie_sim
INPUT az, el and mjd are extracted and sorted by station
group delays are formed and stored scanwise OUTPUT
NGS-filesDATA/SIM
scanantenna
simparamparamfile
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The output of VIE_SIM
NGS-files
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The output of VIE_SIM
NGS-files
we simulate the (o-c) vector and write the (o-c) + c to the observed value in the NGS-files
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The output of VIE_SIM
NGS-files
we simulate the (o-c) vector and write the (o-c) + c to the observed value in the NGS-files
ionosphere correction and cable cal need to be taken into account
22VieVS User Workshop 2011
The output of VIE_SIM
NGS-files
we simulate the (o-c) vector and write the (o-c) + c to the observed value in the NGS-files
ionosphere correction and cable cal need to be taken into account
interface for exchange of simulated data
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Before running VIE_SIM
create an empty OPT directory (e.g. "SIM") and use this for the simulations (if OPT files exist)
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Before running VIE_SIMrename the OPT files for the sessions for which you want to simulate (if OPT files exist)Do not use any outlier files!
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Before running VIE_SIMrename the OPT files for the sessions for which you want to simulate (if OPT files exist)Do not use any outlier files!make sure to set the quality code limit in the 2nd GUI to >9 (it is important that all observations are used for the simulation)
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Before running VIE_SIMrename the OPT files for the sessions for which you want to simulate (if OPT files exist)Do not use any outlier files!make sure to set the quality code limit in the 2nd GUI to >9 (it is important that all observations are used for the simulation)After the simulation you can process the simulated data with any options you like!
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start VieVS as usual
How to start the simulator
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How to start the simulator
start VieVS as usual
in the first GUI choose the sessions for which you want to simulate
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start VieVS as usual
in the first GUI choose the sessions for which you want to simulate
then choose to run VIE_SIM
How to start the simulator
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do not use outlier files!
if OPT files exist, create an empty OPT directory (e.g. “SIM”) and use this for the simulations before starting the simulator.
How to start the simulator
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set the quality code limit to a number > 9
How to start the simulator
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The simulator GUI
choose the parameters to be simulated
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The simulator GUI
enter the number of days and a starting point for the running number of the NGS files
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The simulator GUI
choose a file containing the simulation parameters (can be station specific) …
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Simulation parameter file
station names (8 characters)
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Simulation parameter file
turbulence parametersCn refractive index structure constant [10 -7m -1/3]H effective height of wet troposphere [m]vn, ve components of the wind vector [m/s]
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Simulation parameter file
a priori zenith wet delay [mm]
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Simulation parameter file
correlation interval [h] andstepwidth [m] for the numericalintegration
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Simulation parameter file
clock Allan Standard Deviation (ASD)
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Simulation parameter file
white noise [ps]
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The simulator GUI
… or directly enter the values – these will then be applied to all stations
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The simulator GUI
units! [1e-7m-1/3]
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The simulator GUI
additional option: set reference clock to zero
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simulated NGS files are stored to VieVS / DATA / SIM / year
Where the data are stored
VieVS User Workshop 2011
simulated NGS files are stored to VieVS / DATA / SIM / year
in DATA / LEVEL4 / your_dir you find
Where the data are stored
VieVS User Workshop 2011
simulated NGS files are stored to VieVS / DATA / SIM / year
in DATA / LEVEL4 / your_dir you find
Where the data are stored
a MATLAB structurearray that containsaz, el, and MJDsorted by station
stored only oncefor each session
VieVS User Workshop 2011
simulated NGS files are stored to VieVS / DATA / SIM / year
in DATA / LEVEL4 / your_dir you find
Where the data are stored
a MATLAB structurearray that containsthe mapping functionsorted by station
stored only oncefor each session
VieVS User Workshop 2011
simulated NGS files are stored to VieVS / DATA / SIM / year
in DATA / LEVEL4 / your_dir you find
Where the data are stored
a MATLAB structurearray that containsthe simulated correlationmatrices for each station
stored for eachsimulation
VieVS User Workshop 2011
simulated NGS files are stored to VieVS / DATA / SIM / year
in DATA / LEVEL4 / your_dir you find
Where the data are stored
a MATLAB structurearray that containsthe simulated values ofswd, clk, and wnfor each station
stored for eachsimulation
start VieVS as usual
How to process simulated data
VieVS User Workshop 2011
VieVS User Workshop 2011
choose to use simulated data
How to process simulated data
VieVS User Workshop 2011
select the simulated NGS file(s)
then proceed as
with real data
How to process simulated data
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problems? questions? mail to jing.sun@tuwien.ac.at
Jing Sun would like to thank the FWF for funding project SCHED2010 ((P21049-N14).
Andrea Pany is a recipient of a DOC-fFORTE fellowship of the Austrian Academy of Sciences at the Institute
of Geodesy and Geophysics, Vienna University of Technology.