Applications of Geodesy to Engineering

The local level system is the threedimensional reference frame at hand of an experimeter in an engineering network Accordingly we design a threedimensional engineering network paying attention to the spacetime movement of such a local reference frame with respect to a fixed one attached to the datum point. The influence of the change of the local vertical and horizontal reference directions is outlined and numerically documented. Finally the transformation of one local level reference frame into the global equatorial frame of reference, materialized by the input of satellite (GPS) observations within the engineering network, is given. Numerical examples illustrate the set-up of such a satellite-aided or hybrid engineering network.

Tidal forces produce a wide spectrum of phenomena, from primary luni—solar attractional effects to secondary induced effects like earth and ocean tides, and third order ocean loading effects. Since these phenomena affect precise geodetic observations and make them time-dependent it is necessary to reduce time-variable geodetic observables and derived quantities in order to correspond to a quasi-stationary, time-invariant state. Here we evaluate the tidal corrections to geodetic height determination; (geometrical) height differences observed by GPS are considered as well as physical (orthometric or normal) heights based on geodetic levelling. Special emphasis is given to the impact of the permanent M₀S₀ partial tide, in particular to the indirect effect induced by the permanent deformation. We propose to treat the corresponding tidal corrections to height determination consistently with the IAG Resolution of 1983; this procedure requires another correction term in addition to the generally applied approach. Finally we prove that the tidal correction cannot be neglected in highly precise engineering surveying.

Of all the various possibilities of using an inertial measurement unit (IMU) in surveying engineering only the determination of a reference bearing and its transfer is focussed upon in this paper. Strapdown-systems differ from the conventional gimballed platform-configuration by the use of the sensors which are sensitive to a rotation of the IMU. The gyroscopes, usually three Ringlasergyros or two Dynamical Tuned Gyros are, in addition to the accelerometer triad, fixed to the carrier. Thus the gyros serve as rate sensors and not as stabilizing elements as in the case of gimballed platform-systems. The advantage of fewer hardware components and thus lower hardware purchase and maintenance costs is opposed by the exposition of the sensors to the whole dynamical environment of the carrier. After an initial alignment with respect to the local horizontal frame the determined alignment-angles can be transferred to another control point by a proper evaluation of the sensor output without the necessity of a direct line of sight between the two points. In this paper the potential of the determination of the alignment and its transfer is discussed. In addition some simulation results of corresponding scenarios are presented.

The advent of the Global Positioning System (GPS) has had a significant impact not only on navigation and offshore positioning, but also on engineering surveying and geodesy. GPS is a second generation system of navigation satellites, which is to become fully operational sometime during 1992–93. At present (1991) the GPS constellation is made up of 10 block II (operational) and some (currently 5 working) block I (engineering test) satellites. These provide nearly full 24-hour global 2-D positioning coverage, but only limited 5 to. 6 hour windows of observation for 3-D positioning. When fully operational, there will be 18 (+ 3 spares) Block II satellites offering 24 hour 3-D positioning capability throughout the world.

In this lecture I would like to outline some basic concepts of the theories containing the interesting and surprising potential of being transferable from geodesy to the elastomechanics of structures and vice versa. This not only has opened a completely new field of applications but has allowed also to gain revealing insights into both theories: Adjustment by least squares and elastomechanics of prestressed cable nets. Naturally, I have to confine myself to a few essentials.

Engineering works, such as large dams, demand constant surveillance with safety control purposes, since their failure would, generally, involve considerable losses in life and property. Safety control of large dams relies on behaviour analysis of the works, supported by careful monitoring of a selected group of variates describing the relation between actions and correspondent structural performance, taking into account construction materials characteristics.

This paper describes a method for the determination of movements of an object around a spatial axis. Founded on coordinates of different epochs the rigidity of the object and the spatial position of the axis will be estimated. Finally one application will illustrate the developed theory.

The paper presents generalization of certain model of kinematic network (Kadaj, 1990) for three-dimensional system, taking account of applications to observations of displacements and deformations of engineering constructions (for example water dams).

Electronic sensors for direction and distance measurements and more powerful and cheaper computers opened the way to new applications for electronic theodolites and tacheometers. 3D-measurement systems were developed for surveying of industrial objects using triangulation, trilateration, or polar measurement methods.

The paper describes a unified approach to the alignment of rotating machinery, such as turbines, shafts, rollers, and kilns. It was developed in the context of the Industrial Alignment Project at the University of Calgary which is a cooperative venture between a number of researchers at the university and thirteen companies. The main idea behind this modelling effort was the creation of a common framework in which the observables coming from different sensors could be compared in a consistent manner. The following discussion includes measurements from dial indicators, laser alignment systems, coordinate recording theodolites, CCD cameras and inertial sensors. An example of a dynamic alignment is given to illustrate the usefulness of such an approach to real-life alignment problems.

High-frequency oscillations are important charges on buildings like bridges or straight towers. Especially oscillations, produced by external forces, e.g. braking of a train on a railway bridge or wind load stressing on a straight tower, are to be considered in the static calculations. Therefore for these buildings dynamic models are necessary. The geometrical determination of such high-frequency oscillations on real objects with real charges can be used to check a theoretical dynamic model of an object. In many cases, the oscillations are very short and the object movements are very smaD. So it is not possible to measure these movements with classical geodetical methods in a necessary measurement frequency. For observation of high-frequency oscillations we need instruments which can record and store the object motion in a fast frequency with a sufficient accuracy objectively and automatically. As such an instrument, at the Institut für Anwendungen der Geodäsie im Bauwesen (IAGB) an electronic camera was developed as an external sensor. The principle of this sensor is to be demonstrated in this paper with the measurement of the oscillations of the abutment of a railway bridge during brake of a train as an example. As a second sensor to record the oscillations an accelerometer was used as an instrument on the object itself. The heterogeneous signals of both sensors are evaluated in a joint model, using an adaptive Kaiman Filter.

In this paper some ideas are presented and discussed in order to develop a completely new geodetic monitoring system for an existing arch dam. Taking into account the available knowledge on displacements of the structure and critical areas, it was possible to define requirements for the new monitoring system.During the past few years a number of modern techniques, such as “Automatic Theodolite Systems”, “Terrestrial Photogrammetry” or “GPS” have been developed. The evaluation of these techniques, taking the specific restrictions into consideration, results in an “ideal” new monitoring system.Due to the topography, limited funds and interest of other professional disciplines some compromises had to be made during the implementation of the new systems.

Degradation of natural environment in the Sudetes mountains manifested, among others, by the destruction of woodlands leads to some secondary processes, such as deformations of rocky blocks, which considered most dangerous because of falling rocks down to the roads. Such phenomena can be prevented provided that the mechanisms generating their development will be known. A significant role in achieving this goal is attributed to geodetic surveys which enable monitoring of deformation processes in time and space.

In August 1989 on the north west coast of Peloponnesus earthquake tremors of average Ms = 4.8 of the Richter scale occurred and consequently damage was done to constructions in the area of Agia Triada in the city of Patras. Additionally in the above area a crack of 1500m length appeared on the ground with southwest-northeast direction (approx. azimuth 80°-Fig.1). The direction of the crack coincides with one of the main directions of the faults existing in the wider area. The position of the crack generally is the same with a fault which extends eastern up to Panachaikon mountain. (Kalteziotis et al, 1991). For the detection of vertical displacements a monitoring levelling network was established. Moreover pairs of special markers on both sides of the fault had been placed earlier for the observation of the behaviour of the ground through direct observations.

Planning, setting out and geometric control of complex structures (bridges, tunnels, roofs, power stations, etc.) are becoming more frequent assignments for surveying engineers. In order that these structures disturb the environment as little as possible the demands upon engineering design increase, resulting in complicated plans, and surveillance after the structure is built.

Large and sparse systems of linear equations are obtained in geodesy most frequently in the case of adjustment of geodetic networks. A geodetic network is a mathematical model, usually like a polygonal or triangular graph, consisting of a number of points with unknown positions over a reference surface or in three-dimensional space. Every point in the network represents two or three unknowns. These points are normally connected by lines, each representing one or more observations between the points. The observations may be angles, distances, astronomical determinations, gravitational force of other values connected with unknown positions by non-linear equations. In view of the fact that in a single observation there is only a small number of points, each equation typically involves a small number of unknowns.

The mining of solid mineral resources is carried out mainly by opencast mining in our country. The general volume of migrating mining mass exceeds 7 billion tons. For more effective and rational exploratory development, it is necessary to use mine surveying supply of mining based on the constant replenishment and renovation of mine working plans. The use of stereo-photogrammetry as the main method of stripping mine survey was initiated 40 years ago. This allowed correspondence between the accuracy of a mine survey and its velocity. At present, the mine stereo survey is based on universal photogrammetric devices such as the stereo-autograph, technocart, topocart and stereo-metrograph made by Zeiss (Zeiss Jena) in the USSR.

Profile determination before, during and after excavation on a building site can be done simply and quickly by terrestrial photogrammetry. With this method we avoid the long field measurements and hindrances during construction. The main advantage is that any staking and restaking, if stakes become damaged, is unnecessary. The method is economically competitive with other methods and was tested on the construction site of a steelworks. The results are precise enough to determine the volumes of earthworks.

The impact of underground mining on surface deformation is the subject of many research activities, the final aim of all being prediction, protection, minimization or prevention of negative environmental effects. The fundamental role of surveying data in many research programmes is obvious, as surface subsidence trough is, first of all, a geometrical object. The subsidence trough formation is rather well understood in coal mining. In metal mining it is formed in a less intensive process, mostly governed by local technological and geological conditions. To deal effectively with less intensive and irregular troughs, the observation networks of higher precision are imperative. The objective of this article is to present one of the possible approaches to maintain the high precision of levelling observations between benchmarks of high subsidence velocities.

What are the ultimate building blocks of matter, and what forces act between them? These fundamental questions are being investigated by scientists at the Deutsches Elektronen-Synchrotron (DESY) in Hamburg. As one knows the atomic nucleus consists of protons and neutrons. The protons and neutrons are made of different Quarks. One has to appreciate that the diameter of a proton is only 10-13cm and that of a Quark is smaller than 10-16 cm. Are the Quarks indivisible or can one split them once more? In search of these answers large particle accelerators are being built around the world. Within such an accelerator the protons and/or the electrons will be accelerated to the speed of light. In the area of the experiments the particles make head on collisions, such that the electrons will change their directions when they pass a proton or will collide with a proton and knock out a Quark or perhaps a part of a Quark. The courses of all these particles will be measured and then the physicists hope to answer the questions.

The application of rigorous geodetic procedures in extended engineering projects started in Venezuela in the late 1950s with the Guri Dam and the Maracaibo Lake Bridge projects.These two projects belong to the largest engineering ventures in the world: Maracaibo Bridge is the largest prestressed concrete bridge and Guri Dam is one of the largest dam structures with about 33 km of length at the dam crests.This article includes a description of the main geodetic engineering measurements for these two projects and is extended to include other large structures such as dams, tunnels and bridges: The Uribante-Caparo Dam complex with four individual dams and interconnecting tunnels.The Socuy-Tulé Dam complex including the 5-km-long Tulé Dam and the 1.3-km-long Socuy with interconnecting tunnel and canal structures.The Santo Domingo concrete arc dam situated near a very active fault zone and the Santo Domingo Tunnel of 16 km extension.The Yacambú High Dam with a construction height of 162 m and the 24-km Yacambú Tunnel.The Orinoco Bridge, the largest suspension bridge in South America, with a central span of 712 m.The Limon River Bridge, constructed of 95% prefabricated and prestressed concrete elements.In addition, some specific features of other structures will be mentioned: The 50-km-long Maracaibo Lake Dyke.The dam projects along the Caroni River Basin.The network of the 38-km Queniquea Tunnel.The influence of seismic and tectonic circumstances, etc.

In the process of infrastructure planning and construction, large scale maps such as topographic maps and land-use maps are used. These conventional maps are called 2 dimensional(2D) maps, where geographic objects are represented based on a 2D coordinate system. The conventional maps are suitable for representing terrain features and land-use in rural areas. However, they cannot be successfully applied to the representation of urban space comprising high-rise buildings and underground structures etc. This is because spatial data in the vertical dimension cannot be appropriately represented with conventional 2D expressions except the elevation of a terrain surface. To effectively support the complicated process of planning, construction and management of urban infrastructures, there is a pressing need for a fully three dimensional(3D) modelling of urban space, which allows geographical objects to be represented and located with a 3D coordinate system. Computer mapping makes possible 3D urban space modelling, which is far beyond the capability of the conventional 2D map.

Japan consists of four large islands and other small islands. Hokkaido is the second largest island. The planning of an undersea tunnel connecting the main island of Honshu to Hokkaido was started by Japan National Railways in 1939 and a geological investigation was started in 1946. The western route of the strait was determined from the results of these investigations in 1964 and in the same year the Japanese Railway Construction Agency started to drive the undersea pilot tunnel from both sides of the strait. Excavation of the main tunnel was started in 1971 and completed in 1985, and the tunnel has been used by the railway since March 1988. The tunnel extends for about 54 km and the undersea part is about 23 km long.

The Institute for Deposits and Surveying of the Deutsche Montan Technologie (DMT), Bochum, delivered 3 high precision gyrotheodolites GYROMAT to the English-French-syndicate for the construction of the tunnel under the English Channel. The GYROMATS are in use for direction-finding during the construction of the EUROTUNNEL from both sides.Furthermore, DMT surveying teams carried out control surveys both on the French and on the British side to guarantee a successful breakthrough under the English Channel in December 1990.Within 7 surveying campaigns more than 100 km of bored tunnels in the EUROTUNNEL-project were checked.The GYROMAT and the EUROTUNNEL-project will be outlined in this paper.Finally the results of the control surveys and the influence of horizontal refraction on traverse measurements in tunnels are discussed.

The combination of GPS measurements and levelling yields information on the inclination of the geoid relative to the WGS84 ellipsoid (deflections of the vertical). The same holds for the combination of GPS measurements and astronomic azimuth and latitude determination. Once the inclination components of the geoid are known for an area of operation GPS derived ellipsoidal height differences can be transformed into orthometric height differences. Based on this knowledge the orthometric height difference between the Danish islands Sjælland and Sprogø has been determined. This value is crucial for the setting out of the two 8 km railway tunnels being constructed to establish a fixed link across the Great Belt waterway. Compared with hydrostatic levelling the employed methods offer clear cost advantages.

The new motorway tunnel under the Ems was created between 1985 and 1989 by the Immersed Tube Method. An account is given below of finished construction, basic geodetic surveys, measurement during construction and examining survey after completion. For the project five tunnel elements prefabricated in a dredged dock, each 127,5m long, had to be set across the Ems and lowered one after the other into position. This necessitated continual, accurate supervision of position, height, and inclination of each tunnel element.

For a long time geodesists have been very well versed in handling networks. In almost all countries the ordnance survey is based on a triangulation network. Between the points of a geodetic network directions and distances are measured or the points are used for a photogrammetric analysis (Gauß 1887; Linkwitz 1961; Baarda 1968).

Two methods for determination of horizontal displacements of joints in multistoreyed steel supporting constructions forming power plants, were presented in this paper.Information concerning work on increase of accuracy of determining vertical movements with the use of precise levelling were given. Two problems were discussed in detail, namely: 1.Method of decrease of errors in levelling network caused by changes of length of levelling staffs. The following detailed methods have been prepared: method of field measuring changes of lenght of wooden staff body, caused by temperature and humidity fluctuations, method for computing changes of length of invar tape and recommendations for maintaining staffs and their controlling, in order to keep scale stability.2.Method of reduction of results of levelling surveys, due to technogenic plumb-line inclinations. Method for creating maps of changes of gravity at the regions of opencast mines and barrier lakes has been also prepared.The main aim of research work on industrial measurements, conducted at the Institute of Geodesy and Cartography, is to prepare methods for measuring displacements and deformations of different objects and constructions.

Recent survey results of the navigation market indicate a growing need for precise realtime positioning on land, on sea, in air and space (e.g. navigation of dredging vessels, automated aircraft landing, positioning of airborne sensors). Post-mission analyses of observations using the Global Positioning System have already shown the potential of the GPS system to deliver centimeter accuracies over baselines of several hundreds of kilometers. It is therefore a challenge to develop also a GPS navigation system with such a high accuracy level.The paper introduces a system based on six-channel low-cost C/A code receivers reaching accuracies in the decimeter range in real-time and in the centimeter range for post-mission.The receivers are controlled by separate processors which are communicating via a radio link in the UHF band. The controllers are IBM compatible and are communicating with the receivers via serial interfaces. The hard- and software components and the underlying algorithms are described in detail. The system allows update rates of 1 Hz and the delay for the position fix is less than two seconds.In order to prove the accuracy and the performance of the system several experiments were performed using the system in different environments. Results of these tests are presented.

In industrial dimensional inspection and quality control there is an increasing need for fast and automatic high accuracy measurement systems. For vision systems to match these requirements all system components have to be tuned carefully. A key role in such a system is played by the measurement algorithm. This paper demonstrates how the area-based Multi-Photo Geometrical Constrained (MPGC) matching algorithm can be modified for the highly accurate measurement of object edges. It can be expected that this algorithm allows the measurement of non-targeted, but well-defined object features with a relative accuracy of 1:25000.

By moving a theodolite, it is possible to obtain many images of only one target on the image plane of a CCD camera mounted on a theodolite. In this case, it is not necessary to use ground control points as usually used in conventional photogrammetry. However, when considering calibration of a CCD camera in this system, there is a calibration problem in the 2-D field because the distance between the camera position and target is always the same. Furthermore, the distortion resulting from focal length changes should also be considered during application of this system.This chapter discusses a calibration method in the 2-D field, combined with the conventional photogrammetric method and the constraint condition, and also shows the results of the influence of changing the focal length.

The most often used control networks in mines and tunnels are traverses or traverse networks. The advantages of this kind of control are due to simplicity of its establishment, while shortcomings stem from its limited accuracy. Besides, the traverse control networks are characterized by weak geometry, low number of redundant observations, low degree of reliability, low degree of likelihood of point accuracy assessment (wide confidence intervals), etc. The abovementioned shortcomings can be overcome to a certain degree, when traverses are replaced by chains of elongated rectangles of various arrangement of observations. The arrangement of observations depends on the assumed point accuracy and the measurement technique.

A CCD-sensored robot operated on the basis of an analytical solution of the 3d re-/intersection problem of dimension four is reduced to dimension one by using prior information. Numerical results from an implementation of the closed-form solution of the 3d re-/intersection algorithm on a robot of the ‘Institut für Informatik, Technische Universität München’ are presented.

Measurements were carried out to verify the non-linear calculation methods of longitudinal forces in long, high railway bridges. The practical and theoretical background of the tests is described. Specially chosen methods of loading and measuring the reaction of the structure are appointed to the separate static and dynamic problems.

In this paper a research project entitled as “Rehabilitation of Old Railway Bridges” which was financially supported by NATO Science for Stability with the code name TU-850 BRIDGES” Programme will be briefly presented. Following this, data collection, acquisition and evaluation procedures planned to use for this project will be summarized. Finally, the equipments procured for this project with their properly selected specification will be presented.

It was intentional that I replaced the word “geodesist” in the German title by “surveyor”. If our profession wants to work with and for engineers then geodesy sounds impressive but not inviting.

In this chapter a new method for processing surveying results of the overhead crane in horizontal plane is presented.The method is based on approximation of the rails axle by ordinary algebraic polynomials. Using an optimal number of polynominal elements and observing the boundary conditions it is possible to determine the axis of bridge rails with minimal costs compared with the costs of other methods.

The field of engineering geodesy is looked upon, the problematic, and the state of the art, as well as the activities within the FIG Commission 6 and of other commissions.