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

138 Commission 4 – Positioning and Applications
the digital GNSS signal instead of the “classical” observations
(like code and phase data) allows using and integrating
additional information during reprocessing with
software receivers in post-processing. This is especially
beneficial for situations with large signal obstructions and
in high multipath environments. However, various open
issues are still related to this topic such as the acquisition
problematic in extremely severe conditions (AVILA-RODRI-
GUEZ et al. 2004e, 2005) and the question of optimal GNSS
Signals and codes for the indoor positioning for future
GNSS (AVILA-RODRIGUEZ et al. 2006a).
Consequently alternative methods and positioning techniques
such as wireless LAN are investigated (TEUBER 2006
a,b, TEUBER and HEIN 2005, EISSFELLER et al. 2004). This
method is based on signal strength measurements from the
WLAN access points.
GNSS/INS-Integration
For many navigation applications a GNSS-only solution
is insufficient. Therefore, different sensors such as inertial
navigation systems (INS) can be integrated in and combined
with GNSS technique. The theoretical approaches and
practical test for different INS GPS combinations were
carried out by KREYE et al. 2004, SEIFERT and KLEUSBERG
(2003, 2004) or DOROBANTU and GERLACH (2004a,b).
Further investigations will be directed to integrate optical
odometers.
On the other hand GPS and INS can be combined to
determine the gravity field. The specific forces are
measured by a high precision strap-down INS and the
kinematical accelerations are derived using numerous
differential GNSS observations, cf. KREYE et al. (2005).
STÜRZE and BOEDECKER (2003) showed RMS differences
of 3 mm in the altitude component of the same trajectory
using different GPS receivers with different high sampling
rates. A kinematic lift was developed to provide ground
truth height variations for studying the system behaviour
of the receivers. This way, it has been possible, e.g., to
demonstrate the spectrum deficiency when sampling at
20 Hz instead of 50 Hz, or to carry out ARMA and system
analyses (BOEDECKER and STÜRZE 2006). BOEDECKER 2005
proved that the fusion of attitude information from both
multi antennae GPS and fibre optical gyros provide
transformation parameters between sensor and navigation
frame, long term stability and high value and time
resolution.
GERLACH et al. (2005) carried out an INS/GPS car experiment
in the German Alps for kinematical gravimetry.
During ZUPTs an ordinary Scintrex gravimeter was used
in parallel for validation. They estimated the accuracy of
IMU, during static periods, of a few mGal.
Pseudolites
Pseudolites are GNSS signal emitters on the ground. They
enable to improve the weak satellite geometry (e.g. caused
by obstructions) and to strengthen thus the position determination,
especially of the height component. Consequently,
they play a key role for the development of GNSS-based
precise landing systems (BIBERGER 2006). The adequate
error model for the pseudolite signal reception, especially
on reflecting and conducting surfaces of air planes, are
studied by BIBERGER (2006), TEUBER (2004) and BIBERGER
et al. (2005, 2003a,b). In the context of approaches and
landing different investigations were carried out for groundbased
augmented systems (GBAS) (HECKER et al. 2006a,b)
as well as for enhanced and synthetic vision (KORN and
HECKER 2004a,b, HECKER et al. 2004, 2005) and communications
(SCHÄNZER and FEUERLE, 2003)
For the real world tests of Galileo receivers, the German
Galileo Test and Development Environment (GATE) in
Berchtesgaden and the SeaGate at the Forschungshafen
Rostock are dedicated test facilities which are based on
pseudolite technology.
Applications to kinematic positioning,
guidance and control
Within the project Rudy (Regionale Unternehmensübergreifende
Dynamisierung von Fahrplaninformation, Buchung
und Betrieb im ÖPNV) a geo data based positioning
technique was established for public transport. During the
test in Ulm with 4 public busses equipped with GPRS
technique and a car navigation system, the benefits of the
areawide positioning were shown for the planning of time
tables, the light-signal prioritisation, the monitoring of
buses and the guidance of vehicles in the case of accident,
cf. BETTERMANN (2004a,b), BETTERMANN and KAUFMANN
(2004) or SCHOLLMEYER et al. (2004).
Do-iT (Datenoptimierung für integrierte Telematik) is a
project to improve the acquisition and prediction of traffic
state on and apart from federal motorways. The vehicles’
trajectories are determined with signal strength measurements
of mobile phone data (Floating Phone Data, FPD)
available within the GSM network, and map aiding algorithms
on digital road map, cf. RAMM ET AL (2006) or
WILTSCHKO et al. (2006).
SCHÜLER (2005) analysed the high-precision kinematic GPS
positioning of buoys from IGS and EUREF networks
stations to determine the sea-surface height at the time of
cross over of ENVISAT satellite for the calibration of its
on-board instruments. BÖDER (2006) integrated INS and
GPS for real-time marine and hydrographical applications
in order to overcome data gaps in the GPS time series.
BLUMENBACH (2004, 2005) and BLUMENBACH and HENKE
(2005) investigated the monitoring and the description of
the dynamics of ski jumpers.
Bibliography
NAVITEC = ESA Workshop on Satellite Navigation User
Equipment Technologies
ANGHILERI M. (2006): An Algorithm for Bit Synchronization and
Signal Tracking in Software GNSS Receivers, Proc. ION
GNSS 2006, Fort Worth, Texas
AVILA-RODRIGUEZ J.-A, PANY T. (2004): A combined Galileo/
GPS receiver architecture for consumer market applications,
Proc. NAVITEC 2004, Noordwijk, The Netherlands