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

110 Commission 4 – Positioning and Applications
observations. Work devoted to this topic comprises
BISCHOFF et al. (2005; 2006) as well as HOWIND (2005).
The impact of systematic errors on long baseline kinematic
GPS processing and ambiguity estimation is dealt with in
SCHÜLER (2006).
Precise GNSS Positioning
GNSS is actively and broadly used for positioning in
geodetic applications. Exemplarily, a few prominent uses
are briefly mentioned here with links to other relevant
sections of this national report.
A typical and – in terms of positioning accuracy – highly
challenging application is deformation monitoring as well
as the detection of geodynamic phenomena. An example
for the detection and monitoring of regional deformation
in the Rhine embayment due to coal mining activities can
be found in GÖRRES et al. (2006), displacements in the
Upper Rhine Graben are investigated by ROZSA et al.
(2005), for instance. Vertical ground-motion and intraplate
settings in the Ardenne-Eiffel region are studied in
DEMOULIN et al. (2005). Groups at the TU Karlsruhe and
a number of other research institutions are active regarding
GPS-based deformation analysis ADAM et al. (2002).
Furthermore, 3-dimensional plate kinematics in Romania
can be found in HOEVEN et al. (2004). Please also refer to
section “Commission 3 – Earth Rotation and Geodynamics
– Crustal Deformation and Geodynamics”. Moreover, the
stability of fundamental station Wettzell is monitored by
a cluster of receivers in order to investigate local and
environmental effects (LECHNER, 2003; LECHNER et al.,
2003; SCHLÜTER et al., 2005). A monitoring system for
deformation of buildings like bridges with real-time
capabilities is described by HEIN and RIEDL (2003). Further
aspects of this engineering topic can be found in section
“Applications in Engineering”.
Secondly, a tendency towards an entirely kinematic satellite
orbit determination – i.e. orbit determination by GNSS
positioning – can be observed during the past few years
since more and more low-Earth orbiting (LEO) satellites
are equipped with geodetic-quality GPS receivers for POD
(precise orbit determination). The determination of kinematic
(and reduced-dynamic) trajectories for CHAMP,
GRACE, Jason, COSMIC is exercised by (SVEHLA and
ROTHACHER, 2003; 2005; SVEHLA and FÖLDVARY, 2006),
for instance, with orbits computed for CHAMP and
GRACE covering more than two years in the meantime.
Also, ambiguity resolution for CHAMP and for baselines
between the two GRACE satellites is subject of research
(SVEHLA and ROTHACHER, 2003). Further information can
be found in section “Satellite Orbit Modelling”.
Finally, in recent years, the potential to exploit low-cost
GPS receivers – that were originally manufactured for the
consumer market – for geodetic purposes has been investigated
in detail.
These receivers are typically L1-only devices and are
therefore limited to short-baseline applications. In particular,
GARMIN receivers offer an experimental output of
PLL-related observations (like carrier-phase and Doppler
shift measurements). Although these devices suffer from
several limitations, e.g. half-cycle slips, centimetre-level
point precision can be obtained from static observations
(SCHWIEGER, 2003; 2004; 2005; SCHWIEGER and WANNIN-
GER, 2006).
GNSS/INS-Integration
Although GNSS offers many benefits to the geodetic
community, it is clear that major disadvantages of this
technique are related to availability and continuity of
service (mainly due to obstacles leading to data gaps). For
this reason, research regarding the integration of GPS and
INS (Inertial Navigation Systems) is an ongoing topic
within the community. (KIPKA, 2006) describes such a
combined surveying system that also integrates network
concepts like area correction parameters and virtual reference
station allowing to access active GPS reference
networks (e.g. SAPOS). Further examples for GPS/INS-
Integration can be found in section “Navigation”.
References
ADAM F., DEDE K., HECK B., KUTTERER H., MAYER M., SEITZ K.,
SZUCS L.: GPS deformation measurements in the geodynamic
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