Technical description of dgf2018a.snx
-------------------------------------
1. Purpose: Datum-free VLBI session normal equation files in SINEX 2.02
format, including station/source coordinates and EOP.
2. Analysis Center: Deutsches Geodaetisches Forschungsinstitut (DGFI-TUM),
Technische Universitaet Muenchen, Munich, Germany
3. Estimated parameters:
a. Celestial frame: Yes
b. Terrestrial frame: Yes
c. Earth orientation: Pole coordinates and their first derivatives,
UT1-UTC and LOD, dX, dY, each valid for the duration of the
session (normally 24 h), reference epoch is mid of session
d. Zenith troposphere (per station):
continuous piece-wise linear function (1 hour)
rate constraint 66.0 ps/h
e. Troposphere gradient (per station):
discontinuous piece-wise linear function (24 hours)
offset constraint 2.5 ps
rate constraint 5.0 ps/h
f. Station clocks (per station): Quadratic function per session plus
a continuous piece-wise linear function (1 hour)
offset constraint 66.0 ps
rate constraint 135.0 ps/h
(clock jumps estimated additionally)
4. Celestial reference frame:
a. A priori source positions: ICRF2
b. Source positions adjusted in solution: Yes (>3 observations)
5 Terrestrial reference frame:
a. A priori station positions: ITRF2014
b. A priori station velocities: ITRF2014
c. Axis offsets: taken from official IVS-table
http://vlbi.geod.uni-bonn.de/Analysis/Thermal/antenna-info.txt
d. Reference epoch: session epoch
6. Earth orientation:
a. A priori precession/nutation model: IAU2006A
b. A priori x and y pole coordinates and rates, UT1-UTC and rate:
IERS EOP 14 C04, cubic window interpolation
c. A priori short period (~daily and subdaily) tidal variations in
x, y, dUT1: IERS Conventions 2010
d. EOP estimation: Pole coordinates and rates, UT1-UTC and rate (UT1dot),
dX, dY, each valid for the duration of the session
(normally 24 h), reference epoch is mid of session (see the
SOLUTION/APRIORI block)
7. A priori geophysical models:
a. Troposphere: hydrostatic component from surface pressure (in
general as reported in the NGS files) mapped with the VMF1
dry mapping function, wet delay is estimated with the VMF1
wet mapping function. A priori values for the gradients are
from TU Wien (Boehm & Schuh, 2007) since 2005.0 and from GSFC
(MacMillan, 1995, and MacMillan & Ma, 1997) before 2005.
b. Solid Earth tide: IERS Conventions 2010
c. Tidal ocean loading: FES2004
d. Pole Tide: IERS Conventions 2010
e. Atmosphere loading: Petrov & Boy (2003)
https://lacerta.gsfc.nasa.gov/aplo_eph/
f. Thermal deformation: according to IVS conventions
http://vlbi.geod.uni-bonn.de/Analysis/Thermal/antenna-info.txt
8. Data type: Group delays
9. Data editing: 5-degree elevation cut-off
10. Data weighting: Only observations with a zero quality flag in NGS
cards are used. All observations are subject to an outlier test
(data snooping).
11. Software: DOGS-RI 1.0
12. Further information:
The SINEX 2.02 files include datum-free normal equations only, no
solution. None of the station/source position parameters or EOP reported
in this file are subject to any constraints.