SPECIAL
COMMISSION 4:
"APPLICATION OF GEODESY TO
ENGINEERING"
Introduction Rapid
developments in engineering, microelectronics and the computer
sciences have greatly changed both the instrumentation and methodology
in Engineering Geodesy. The objectives of the Special Commission are
on the one hand to document the body of knowledge in this field, and
on the other hand to encourage new developments and present them in a
consistent framework. Symposia and workshops are planned to document
the current state of development in engineering applications of
geodesy. Working Groups were established in areas of current research
interest which will have specific goals to ensure that their research
work can be accomplished in a four year period. In addition, there is
considerable collaboration with other international organisations such
as the ISPRS, FIG, and the ION. SC4
WG 1: “Real-Time Mobile Multi-sensor Systems and Their Applications
in GIS and Mapping” To
fulfil the need for up-do-date inventory and geometric data along
transportation routes (e.g. roads, railways, rivers, pipelines, etc.)
Mobile Multi-sensor Systems (MMS) are being operated. In general, MMS
have in common that they integrate a set of sensors mounted on a
single platform, and synchronized to a common time base. They are
typically operated in kinematic mode. In principle, they are capable
of operating only with the data measured on the platform, that is, no
other information (such as external ground control) is needed,
although it may be included as redundant information. Systems of this
type:
The
objectives of the Working Group are: Identify
and promote new developments in MMS. Identify
and promoted new applications for MMS. Encourage
and document emerging processing techniques for MMS. Chairman:
Naser El-Sheimy (Canada) SC4
WG 2: “Dynamic Monitoring of Buildings and System Analysis” The
world records for bridge span and building height have increased more
than tenfold in the second millennium. In the 20th century alone, the
record height for a building has increased from 118m to 452m, while
the record for a bridge span has increased from 521m to 1991m. As
can be seen from these records, quality control of these structures is
a challenging task. The goals of the monitoring methods are:
assessment of the structural behaviour (safety inspection) and
improvement of maintenance (optimization of repair, early detection of
damage, etc.). The input for the monitoring methodes can be forced or
ambient vibrations. Then "Forced Vibration Testing" (FVT)
and "Ambient Vibration Testing" (AVT) can be applied. Instruments,
used to monitor the motions, are often fixed to the object under
motion. That means that their dynamic parameters change depending on
the frequencies of the motions. The goal of this Working Group is, to
study dynamic monitoring methods, sensor systems and system analysis
models for quality control of large manmade structures.
Interdisciplinary collaboration will be necessary. Chairman:
Wolfgang Niemeier (Germany) SC
4 WG 3: “Monitoring of Local Geodynamic Processes and System
Analysis” Monitoring
and system analysis of landslides, mudflows and rockslides has become
of great importance, since the population of the world is increasing
dramatically and, as in many cases, housing estates and industrial
sites were erected without taking these geodynamic processes into
consideration. In
mountainous areas, for instance, as in the European Alps, it is
estimated that about 6% of the country is affected by landslides.
Along the Yangtze River in China, in the vicinity of the Three Gorges
Dam Reservoir, for instance, about 100 landslide sites have to be
monitored. Their average velocities can vary from 1 to 200mm/year, and
in general the movements are fairly regular, especially on large
slopes. In some cases there are reactions according to the climate
conditions. However, sometimes instabilities are possible, which cause
the velocities to be multiplied by a factor 100 and greater, sometimes
resulting a disaster failure. The
main goals of the Working Group are to study: Computer-controlled
MMS recording geodetic, geophysical and meteorological data. Different
models of system analysis. Models
for disaster/failure prediction. Chairman:
Gyula Mentes (Hungary) SC
4 WG 4: “Geodesy on Large Construction Sites” The
growing world population and the globalization of the economy demands
improved traffic systems, power stations and construction of dwellings
and bureau centres. Therefore in the future large construction sites
will have to be managed. Geodetic methods and techniques can
contribute to do this management in a most economical way. There will
be large construction sites for high speed railway lines, tunnels,
bridges, power dams, airports, and so on. The
main goals of the Working Group will be to study: 1.
The design of networks based on permanent GPS stations. 2.
The navigation of construction machines. 3.
High precision alignment methods. 4.
Information systems based on geodetic-geotechnical-geological
data. Chairman:
A new chairman will be nominated within two months. SC
4 WG 5: “Pseudolite Application in Engineering Geodesy” In
satellite-based precise positioning, the dominant factors are the
number and geometric distribution of the satellites tracked by
the receivers. In the case of global navigation satellite systems (GNSS)
such as GPS, Glonass, and the planned Galileo system, four visible
satellites are the minimum requirement for precise three-dimensional
positioning. In general, the more satellites that are tracked, the
more reliable the positioning solutions. However, in some situations,
such as in downtown urban canyons, engineering construction sites, and
in deep open-cut pits and mines, the number of visible satellites may
not be sufficient. In the worst situations, such as in underground
tunnels and inside buildings, the satellite signals may be completely
lost. Such problems with existing GNSS systems can be addressed by the
inclusion of additional ranging signals transmitted from ground-based
"pseudo-satellites" (pseudolites). Pseudolites are an
exciting technology that can be used for a wide range of positioning
and navigation applications, either as a substantial augmentation tool
of spaceborne systems, or as an independent system for indoor
positioning applications. The
goal of this proposed Working Group is to study new concepts of
pseudolite-related positioning and, in particular, applications of
pseudolites in engineering geodesy. Major objectives of the research
activities are to study: 1.
Pseudolite augmentation of GPS system. 2.
Pseudolite-only positioning scenarios. 3.
Integration of pseudolites with other sensors, such as INS. These
objectives will be achieved by: ·
Promoting
discussions between Working Group members. ·
Setting
up a Working Group website providing a focus for pseudolite research
and applications with the relevant links. The web site is located at:
http://129.94.250.108/iag-sc4-wg5/index.html. ·
Developing
a comprehensive bibliography dealing with pseudolite research and
applications. Chairman:
Jinling Wang
(12 members) SC
4 WG 6: “Application of Knowledge-Based Systems in Engineering
Geodesy” For
many geo-(but also non-geo-)disciplines the results of geodetic
measurements (coordinates, displacements, etc.) serve as a basis for
solving problems such as interpretation, documentation, recognition,
control, design, prediction, diagnose, alarming, simulation, and so
on. Examples are the (intelligent) control of measurement or guidance
systems, the detection of outliers, or the early recognition of
noticeable patterns in the displacement data of tunnels under
construction, etc. For these tasks geodetic data often must be
considered incomplete and uncertain, and in most cases additional
knowledge from experts of the specific application field is needed. Nowadays
there is a growing demand for geodesists to work in interdisciplinary
teams and to contribute to the development of appropriate systems and
techniques that help to solve these problems in a more 'intelligent'
and 'automatic' manner. The application of AI-methods, such as
Knowledge-based Systems, seems to be a promising approach, gence this
research for, and applicability in, Engineering Geodesy will be the
main objective of the Working Group. Chairman:
Klaus Chmelina
(5 members) Conference
Activities WG
1 was organiser of the conference "3rd International
Workshop on Mobile Mapping Technology", 3-5 January, 2001 in
Cairo, Egypt. A report on the conference can be downloaded from the
SC4 websites. Websites:
http://info.tuwien.ac.at/ingeo/sc4/sc4_99-03.htm Working
Groups WG 2 and WG 3 have organised a workshop on "Monitoring of
Constructions and Local Geodynamic Processes", held in Wuhan, P.R.
China, from 22-24 May, 2001.
Websites:
http://info.tuwien.ac.at/ingeo/sc4/wuhan01.htm
http://www.wtusm.edu.cn/wuhan01.htm The
Special Commission is co-sponsor of the "5th
Conference on Optical 3-D Measurement Techniques", which will be
held in Vienna, Austria, 1-4 October, 2001.
Websites:
http://info.tuwien.ac.at/ingeo/optical3d/o3d.htm The
Special Commission is organising the "2nd Conference
on Geodesy for Geotechnical and Structural Engineering", which
will be held in Berlin, Germany, 21-24 May, 2002. This will be the
meeting where all the WGs will come together to present their
scientific programs and report on their current research work.
Websites:
http://info.tuwien.ac.at/ingeo/sc4/berlin.html
http://www.sc4-berlin2002.de.vu/
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