vievs user workshop 14 – 16 september, 2011 vienna vie_sim jing sun, andrea pany

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?


What is simulated?

o-c = (zwd2·mf(el2) + clk2) – (zwd1·mf(el1) + clk1) + wnbsl


What is simulated?station 2 station 1



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



What is simulated?

mf(el) - mapping function (elevation)

station 2 station 1

zenith

mapping function


you should use thesame mf for the creationof the simulated files andfor the processing of thesimulated data – unlessyou want to study mf errors


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



What is simulated?

wnbsl - white noise per baseline

station 2 station 1



VIE_INIT

VIE_MOD

VIE_SIM

VieVS and VIE_SIM


VIE_INIT

VIE_MOD

VIE_SIM

VieVS and VIE_SIM

artif

icia

l

NGS file

s


VIE_INIT

VIE_MOD

VIE_SIM

VIE_INIT

VIE_MOD

VIE_LSM

VieVS and VIE_SIM

artif

icia

l

NGS file

s


Data flow in VIE_SIM

vie_sim

scanantenna

simparamparamfile

INPUT



INPUT az, el and mjd are extracted and sorted by station

vie_sim

scanantenna

simparamparamfile



sim_swd

sim_clk

sim_wn


vie_sim

scanantenna

simparamparamfile



sim_swd

sim_clk

sim_wn

vie_sim


group delays are formed and stored scanwise

scanantenna

simparamparamfile



sim_swd

sim_clk

sim_wn

vievs2ngs

vie_sim


group delays are formed and stored scanwise

scanantenna

simparamparamfile



sim_swd

sim_clk

sim_wn

vievs2ngs

vie_sim


group delays are formed and stored scanwise OUTPUT

NGS-filesDATA/SIM

scanantenna

simparamparamfile


The output of VIE_SIM

NGS-files



NGS-files

we simulate the (o-c) vector and write the (o-c) + c to the observed value in the NGS-files



NGS-files


ionosphere correction and cable cal need to be taken into account



NGS-files


ionosphere correction and cable cal need to be taken into account

interface for exchange of simulated data


Before running VIE_SIM

create an empty OPT directory (e.g. "SIM") and use this for the simulations (if OPT files exist)


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!


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)


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!


start VieVS as usual

How to start the simulator




in the first GUI choose the sessions for which you want to simulate



in the first GUI choose the sessions for which you want to simulate

then choose to run VIE_SIM



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.



set the quality code limit to a number > 9



The simulator GUI

choose the parameters to be simulated


The simulator GUI

enter the number of days and a starting point for the running number of the NGS files


The simulator GUI

choose a file containing the simulation parameters (can be station specific) …


Simulation parameter file

station names (8 characters)



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]



a priori zenith wet delay [mm]



correlation interval [h] andstepwidth [m] for the numericalintegration



clock Allan Standard Deviation (ASD)



white noise [ps]


The simulator GUI

… or directly enter the values – these will then be applied to all stations


The simulator GUI

units! [1e-7m-1/3]


The simulator GUI

additional option: set reference clock to zero


simulated NGS files are stored to VieVS / DATA / SIM / year

Where the data are stored

VieVS User Workshop 2011


in DATA / LEVEL4 / your_dir you find






a MATLAB structurearray that containsaz, el, and MJDsorted by station

stored only oncefor each session





a MATLAB structurearray that containsthe mapping functionsorted by station

stored only oncefor each session





a MATLAB structurearray that containsthe simulated correlationmatrices for each station

stored for eachsimulation





a MATLAB structurearray that containsthe simulated values ofswd, clk, and wnfor each station

stored for eachsimulation


How to process simulated data



choose to use simulated data



select the simulated NGS file(s)

then proceed as

with real data



problems? questions? mail to [email protected]

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.

mailto:[email protected]

vievs user workshop 14 – 16 september, 2011 vienna vie_sim jing sun, andrea pany

Documents

sim sim

sim vievs

sim slide

clk sim

vievs user workshop

swd sim

sim jing

sim input az