vievs user workshop 14 – 16 september, 2011 vienna vie_sched jing sun
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VieVS User Workshop
14 – 16 September, 2011
Vienna
VIE_SCHED
Jing SUN
VieVS User Workshop 2011 2
What’s the purpose of a scheduling program ?
Scheduling Program
Station
prc file, snp file
DRUDG
FS
Correlator
skd fileskd file
log file
Current scheduling
programs :
sked (Goddard)
sched (NRAO)
...
VieVS User Workshop 2011 3
Why is a new scheduling program needed?
VLBI2010 Goals1 mm measurement accuracy on global baselines
continuous measurements for time series of station positions and EOP
turnaround time to initial geodetic results of less than 24 hrs.
VLBI2010 Specificationssmall fast-moving antennas
broadband frequency (2–14 GHz)
two or more antennas at a site
…
VieVS User Workshop 2011 4
'source.cat'; % source positions 'flux.cat'; % source fluxes
'antenna.cat'; % antenna information 'position.cat'; % station x,y,z locations 'equip.cat'; % equipment IDs 'mask.cat' ; % horizon and coordinate masks
'freq.cat'; % frequency sequences 'rx.cat'; % receiver setups'loif.cat'; % station Lo and IF setups'rec.cat'; % recording modes'hdpos.cat'; % head offsets'tracks.cat'; % standard recorded tracks
'modes.cat'; % observing modes SKD file
NGS file
SKD-sum file
Input filesOutput files
VieVS User Workshop 2011 5
Source dependent scheduling strategy
0 50 100 150 200 250 300 350
-80
-60
-40
-20
0
20
40
60
80
right ascension [deg]
decl
inat
ion
[de
g]
VieVS User Workshop 2011 6
Source dependent scheduling strategy
0 50 100 150 200 250 300 350
-80
-60
-40
-20
0
20
40
60
80
right ascension [deg]
decl
inat
ion
[de
g]
VieVS User Workshop 2011 7
Base on a more global station distribution
Simple and effective
Source dependent scheduling strategy
VieVS User Workshop 2011 8
Station dependent scheduling strategy
divide the sky above the station in 13 segments;
count the segments which contain at least one observed source in a certain time interval.
the best possible sky coverage: 13
VieVS User Workshop 2011 9
VLBI2010 simulations
Longitude [deg]
Lat
itude
[de
g]
station distribution
-180 -90 0 90 180-90
-40
0
40
90
--- legacy antennas --- fast slewing antennas
Interim network : 18 stations
Schedule parameters
VieVS User Workshop 2011 10
VLBI2010 simulations
From VIE_SCHED_1
2 sources in a subnetsouce-dependent
From VIE_SCHED_2
3 sources in a subnetsouce-dependent
From VIE_SCHED_3
station-dependent
Number of sources
197 190 225
number of scans
2102 3371 4138
number of observations
67633 53828 84398
number of observations
VieVS User Workshop 2011 11
distribution of observations
From VIE_SCHED_1 From VIE_SCHED_2 From VIE_SCHED_3
0 2 4 6 8 10 12 14 16 18 200
2000
4000
6000
8000
10000
12000
14000
station index
num
ber
of o
bser
vatio
ns
VieVS User Workshop 2011 12
spatial coverage of sources
0 5 10 15 20 25 30 35 40 45 5045
50
55
60
65
70
time index
spat
ial c
over
age
valu
e [%
]
From VIE_SCHED_1 From VIE_SCHED_2 From VIE_SCHED_3
VieVS User Workshop 2011 13
idling percentage
From VIE_SCHED_1 From VIE_SCHED_2 From VIE_SCHED_3
0 2 4 6 8 10 12 14 16 180
10
20
30
40
50
60
70
80
90
station index
perc
enta
ge v
alue
[%
]
obs
slew
idle
0 2 4 6 8 10 12 14 16 180
10
20
30
40
50
60
70
80
90
station index
perc
enta
ge v
alue
[%
]
obs
slew
idle
VieVS User Workshop 2011 14
mean sky coverage
From VIE_SCHED_1 From VIE_SCHED_2 From VIE_SCHED_3
0 2 4 6 8 10 12 14 16 187.5
8
8.5
9
9.5
10
10.5
11
11.5
station index
mea
n sk
y co
vera
ge v
alue
VieVS User Workshop 2011 15
Simulation parameters• the refractive index structure constant Cn :• the effective height of wet troposphere H : 2000 [m]• the wind velocity vector v (8.0 m/s) towards east• the Allan standard deviation (ASD) of 1e-14 @ 50 min• the white noise : 16 ps per baseline
Estimated parameters• NNR/NNT for all a priori station coordinates; source coordinates fixed to ICRF2.• EOP offsets for each 24-hour session.• Quadratic function plus 60 min piecewise linear function for clocks with relative
constraints of 42 ps.• 6 min piecewise linear function for zenith wet delays with relative constraints of 19
ps.• 10 min piecewise linear function for gradients with 1.4 mm relative constraints and 1
mm absolute constraints.
VieVS User Workshop 2011 16
station position repeatibilities
mean station position repeatibilities = 3.61
mean station position repeatibilities = 3.55
mean station position repeatibilities = 3.72
From VIE_SCHED_1 From VIE_SCHED_2 From VIE_SCHED_3
0 2 4 6 8 10 12 14 16 18 200
1
2
3
4
5
6
7
station index
3D r
ms
[mm
]
VieVS User Workshop 2011 17
baseline length repeatibilities
From VIE_SCHED_1 From VIE_SCHED_2 From VIE_SCHED_3
0 2000 4000 6000 8000 10000 12000 140000
1
2
3
4
5
6
7
8
9
baseline length [km]
rms
[mm
]
VieVS User Workshop 2011 18
Ongoing and planned developments of VIE_SCHED
Variance and covariance analysis and even a dynamic optimization process
Twin/multiple telescopes at a site
Spacecraft tracking
Interactive interface
More analyses and comparisons
----- with sked, sched and other scheduling package
VieVS User Workshop 2011 19
Thanks for your attention!
problems? questions? mail to [email protected]
Jing Sun would like to thank the FWF for funding project SCHED2010 (P21049-N14).