NATIONAL REPORT OF THE FEDERAL REPUBLIC OF ... - IAG Office

104 Commission 4 – Positioning and Applications
investigations. The system is in the construction phase, first
observations are expected in 2008. The existing Wettzell
Laser ranging system (WLRS) will be optimised for Lunar
tracking and for tracking high orbiting satellites like the
GNSS-satellites.
The ILRS Analysis Centres at BKG, DGFI, GFZ are
routinely processing tracking data to the geodetic satellites
Lageos-1/2 and Etalon-1/2 on a weekly basis. These solutions
contain station coordinates and Earth Orientation Parameters
(EOP). This processing includes also the computation
of pass-dependent biases, which are published at the
DGFI Homepage http://www.dgfi.badw.de/dgfi/ILRS-AC/
quality/index.html. The output is generated in SINEX
format for subsequent combination with other SLR
solutions. At the ILRS/AWG meeting in June 2004 in San
Fernando (Spain) ASI (Italy) has been nominated as the
primary ILRS combination centre while DGFI was selected
as the backup combination centre. Both combination centres
are responsible for the weekly combination of the contributions
from the individual analysis centres. The combined
products are delivered to the ILRS Data Centres which are
maintained at CDDIS and at DGFI (EUROLAS Data
Centre, EDC). The entire SLR data from 1993 to 2005 has
been re-processed and re-combined to serve as input for
ITRF2005.
LLR
At the IfE (Institut für Erdmessung, Institute of Geodesy,
Leibniz University Hannover), which is an official lunar
analysis center of the ILRS, the software to analyze the
LLR data has been converted from Fortran 77 to Fortran
90 (KOCH 2005) in spring 2005. A further item in the past
years was the implementation of a new integrator for the
numerical integration of the ephemerides of the main solar
system bodies and the dynamical partials with sufficient
accuracy. With the new software package, standard solutions
for the determination of the unknown parameters were
carried out using all LLR measurements between 1970 and
2006, about 16, 000 normal points. Besides the ‘Newtonian’
parameters of the Earth-Moon system, many relativistic
effects were investigated such as the validity of the equivalence
principle or predictions of alternative theories of
gravity (e.g. MÜLLER et al. 2006).
In May 2006 a new LLR project imbedded in a German
research unit of the DFG (German Research Foundation)
dedicated to “Earth rotation and global dynamic processes”
has been set up.
In cooperation with U. SCHREIBER, Wettzell, and J. OBERST,
DLR, IfE started to investigate the poor observational
conditions in LLR and to think about possible improvements
by new installations on the Moon. In this respect
investigations of how the various reference frames are
affected have been performed (MÜLLER et al. 2007).
In the future, LLR results shall be provided to a larger user
community via ILRS and IERS. The contribution of LLR
for geodetic applications and its visibility shall further be
improved by J. MÜLLER (IfE) who serves as LLR representative
in the ILRS Governing Board and as ILRS represen-
tative in the Directing Board of the International Earth
Rotation and Reference Systems Service (IERS) since 2006.
DORIS
No major activities related to the French DORIS (Doppler
Orbitography and Radiolocation by Satellite) system were
observed in Germany.
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