berichte 2011 - Förderergesellschaft der Geodäsie und ...

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BERTA: B ESCHREIBUNG UND KORREKTUR VON GNSS-M EHRWEG-EFFEKTEN MITTELS
RAY-TRACING UND SOFTWARE-E MPFÄNGERN (BMWI/DLR, MARIOS SMYRNIAOS)
BERTA project is realized through the corporation of the Institut für
Erdmessung (IfE) and the Institut für Nachrichtentechnik (IfN) of the Technical
University of Braunschweig.
The primary goal of the project is to investigate and understand multipath
propagation effects in GNSS receivers so that a model can be derived for
the correction of phase observations.
CARRIER-TO-NOISE DENSITY RATIO VALUES FOR SATELLITE PRN16 AT TWO DAYS OBSERVED IN
A ZERO BASELINE SCENARIO WITH TWO RECEIVERS (LEICA/JAVAD)
High precision GNSS applications, like GNSS reference station applications,
require mm accuracy while phase errors due to multipath propagation
may reach up to cm level. Considering the fact that most of the other
GNSS error sources can be modelled or significantly reduced by differential
techniques, site dependent errors and multipath propagation especially
are very crucial for the achieved positioning accuracy. The previous justifies
the intense research that takes place in the last decades in the field of
multipath detection and/or mitigation.
In the current investigation, a ray-tracing method is used to model deterministically
the satellite-to-earth channel. Simulated ray paths characteristics
are very useful for the deeper understanding of the process. Moreover
the disturbances between the simulations and the actual GNSS observations,
both from geodetic and software GNSS receivers, will lead us to a
correction model for the phase observations.