iaai0104.eopi.txt
Contact: Zinovy Malkin (malkin@quasar.ipa.nw.ru)
Last updated: 21.12.2001
Technical description of solution iaai0104.eops
1. Purpose of solution: Intensives UT1
2 - Analysis Center: Institute of Applied Astronomy (IAA)
3. Short narrative description of solution:
Intensives sessions (delays only) are analyzed for this solution.
Files in the NGS format are used as source of observables. Model of
reduction follows IERS Conventions (2000) except relativistic correction
which is computed according to IERS Standards (1992). Also advanced
model for thermal antenna deformation is used. Wet tropospheric delays
and clock offsets are modeled as random walk stochastic process and
estimated using Kalman filter technique. Wettzell is used as reference
station for clocks estimation when available. Antenna thermal
deformations are modelled using IAG/ETC MG 6 model (DGFI Report, No.71)
with modification providing accounting for horizontal deformations.
Antenna dimensions file supported by the IVS AC is taken for this
computation.
4. Estimated parameters:
a. celestial frame: No
b. terrestrial frame: No
c. Earth orientation: UT1-UTC
d. zenith troposphere: Random walk process
e. troposphere gradient: No
f. station clocks: Polynomial + random walk process
g. baseline clocks: No
h. other: No
5. Celestial reference frame:
a. a priori source positions: ICRF-Ext.1
b. source positions adjusted in solution: No
e. solution identification or reference: ICRF-Ext.1
6 - Terrestrial reference frame:
a. a priori station positions: ITRF2000
b. a priori station velocities: ITRF2000 velocity field
c. reference epoch: 1997.0
d. station positions/velocities adjusted in solution: No
l. solution identification or reference: ITRF2000
7. Earth orientation:
a. a priori precession model: IAU(1976)
b. a priori nutation model: MHB2000
c. a priori short-period tidal variations in x, y, UT1:
IERS Conventions (2000);
zonal tidal variations are included in UT;
daily and subdaily variations are not included in EOP
d. EOP estimation: UT1-UTC every session
8. A priori geophysical models:
a. troposphere: Saastamoinen model for zenith delay,
NMF mapping function
b. solid Earth tide: IERS Conventions (2000)
c. ocean loading: IERS Conventions (2000)
d. atmosphere loading: dH = C*(P-P0)
9. Data type: delays
10. Data editing: Only data with zero quality flag in NGS file are used;
supplemental editing of outliers is applied during adjustment when
necessary
11. Data weighting: First, observations are weighted using std reported
in observational files and a priori additive variance;
further re-weighting is applied for each session to achieve chi-square
of unity in a session solution
12. Standard errors reported: Reported formal errors are derived from
least-square and Kalman filter adjustment without supplemental correction
13 Software: OCCAM/GROSS
14. Other information:
1. Supplement fields after standard IERS/IVS ones contain:
- experiment name
- number of stations
- chi-square
format 1:
- reference station for clock estimation
- degree of polynomial for deterministic part of clock variations
- TRF/CRF catalog used
format 2:
- degree of polynomial for deterministic part of clock variations
- TRF/CRF catalog used
- list of stations used for computation of reported EOP, reference
station for clock estimation is listed first