Multi sensor systems are used for an extensively and efficiently data acquisition, which leads to
the creation of planning criteria, machine control, performing quality testing or documenting
workflow, for instance. The recorded object can be modeled or controlled according to the integrated
sensor modules of the measuring system. Thus, beside pure geometrical information like
position, size and surface structure, characteristics like material, color or temperature can be determined
if necessary. Especially at track surveying multi sensor systems have found a wide
range of application.
The track geometry of a subgrade is defined by a sequence of individual subgrade elements.
Measuring profiles are determined in certain intervals to transfer the geometrical information
along the subgrade for pegging and monitoring purpose at which due to the repeating measuring
process automated track surveying systems are normally applied. The track surveying system
RACER II (rapid automated control equipment for rails) determines the track geometry by contact-
free measurement of the rail surface based on laser triangulation sensors and thereby represents
a fast and low-wear multi sensor system. The RACER II was specially developed for the
high accuracy requirements for monitoring the installation of the slab track within the Gotthard
base tunnel.
The relative orientation of the four integrated laser triangulation sensors on the measuring platform,
whose knowledge has to be assumed, is described by 6 parameters (3 translations, 3 rotations)
for each sensor (6 DoF, degrees of freedom). As neither the point of origin, nor the direction
of the coordinate axis of the laser triangulation sensors can be signalized directly, the 6-DoF
parameters have to be determined indirectly. Within this thesis, approaches to solve the determination
of 6-DoF parameters from different reference geometries as well as the practical implementation
for the RACER II are described.
Another focus is the deduction of the track geometry from measuring data of the laser triangulation
sensors linked with tachymetric measurements for the georeferencing. For this, this thesis
makes a contribution concerning data handling, segmentation and modeling as well as implemented
procedures for quality assurance for the measurement data of the laser triangulation sensors
by the example of the RACER II. The compliance of project-specific accuracy requirements
is confirmed by extensive validation measurements.
«Multi sensor systems are used for an extensively and efficiently data acquisition, which leads to
the creation of planning criteria, machine control, performing quality testing or documenting
workflow, for instance. The recorded object can be modeled or controlled according to the integrated
sensor modules of the measuring system. Thus, beside pure geometrical information like
position, size and surface structure, characteristics like material, color or temperature can be determined
if...
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