J. M. Rüeger’s research while affiliated with UNSW Sydney and other places

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Publications (39)


On system calibration and type testing of digital levels
  • Article

April 2000

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145 Reads

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28 Citations

J.M. Rüeger

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In this paper, a new measurement procedure is presented for the system calibration of digital levels using a vertical comparator. The proposed routine system calibration yields information about the scale of the coded invar staff, the accuracy and the errors of the instrument-staff measuring system, with the staff in its vertical working position. The calibration is carried out at 3 m distance and, additionally, at a typical sighting distance. The proposal is based on a thorough review of the development of the system calibration and the type testing of digital levels. The error sources of digital levels and staffs are discussed and the technical data of the current digital levels are tabled.


Staff errors in and the adjustment of ordinary levelling runs

March 1997

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106 Reads

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6 Citations

Australian Surveyor

Even though ordinary levelling with wooden, fibreglass and aluminium staffs is carried out on a daily basis, few observers are aware of the relatively large errors of these staffs and fewer still employ adjustment procedures for the levelling data which offset these errors. Predicting the graduation and expansion errors of ordinary staffs and adding systematic refraction errors, the likely maximum scale errors are estimated as 11 mm per 10 m height difference. Formulae and numerical examples are given for three different adjustment methods. Their suitability is discussed and their results are compared.


Staff Errors in and the Adjustment of Ordinary Levelling Runs

March 1997

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5 Reads

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6 Citations

Australian Surveyor

Even though ordinary levelling with wooden, fibreglass and aluminium staffs is carried out on a daily basis, few observers are aware of the relatively large errors of these staffs and fewer still employ adjustment procedures for the levelling data which offset these errors. Predicting the graduation and expansion errors of ordinary staffs and adding systematic refraction errors, the likely maximum scale errors are estimated as 11 mm per 10 m height difference. Formulae and numerical examples are given for three different adjustment methods. Their suitability is discussed and their results are compared.


Electro-Optical Distance Meters

January 1996

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136 Reads

Distance meters featuring visible light or near infrared (NIR) radiation as carrier waves are called electro-optical EDM instruments. These carrier waves follow the laws of geometrical optics; normal telescopes are used for transmitting and receiving the signals.


Reflectors

January 1996

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19 Reads

Apart from military laser rangers, electro-optical EDM instruments need a device at the target station which reflects the light (or infrared) beam back to the instrument. Reflecting devices should have the following properties: 1. good reflectivity 2. complete illumination of the receiver optics of the instrument 3. no change direction of emerging rays through small movements of the reflecting device, thus rendering a continuous alignment unnecessary.


Errors of Electro-Optical Distance Meters

January 1996

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35 Reads

All electro-optical distance meters suffer from a large number of usually very small instrumental errors, irrespective of the use of the pulse measurement or phase measurement principle. The errors may be inherent to the electrical and optical design and/or caused by manufacturing and component tolerances. The magnitude of these errors is kept small by the manufacturers and usually accounted for in the accuracy specifications of instruments. In view of the fact that a small number of errors must be calibrated by the user of EDM instruments and that errors occasionally exceed the specified accuracy and may change with time, the user must be aware of the main error pattern of instruments.



Physical Laws and Units Related to EDM

January 1996

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10 Reads

The frequency f and the wavelength λ of electromagnetic waves are related by the following fundamental equations: λ=cf;\lambda = \frac{c} {f}; (2.1) f=cλ,f = \frac{c} {\lambda }, (2.2) where c = velocity of electromagnetic waves in a medium, usually referred to as the velocity of light in the medium f = frequency of signal λ = wavelength in the medium.


Velocity Corrections to Measured Distances

January 1996

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14 Reads

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2 Citations

The basic formula for the computation of d was introduced in Sections 2.1 and 3.1.1. Equation (3.1) may be written, after substitution of Eq. (2.4) for c, to describe the distance value d′ actually displayed on a distance meter. d=c0nREFΔt2,{{d}^{'}}=\frac{{{c}_{0}}}{{{n}_{REF}}}\frac{\Delta {{t}^{'}}}{2}, (6.1) where d′ = the distance displayed on the EDM instrument, c0 = the velocity of light in a vacuum, Δt′ = the measured “flight” time of the signal to the reflector and back, nREF = the reference refractive index of the instrument.


Calibration of Electro-Optical Distance Meters

January 1996

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12 Reads

In this context, the calibration of a distance meter is defined as the determination of its instrument correction and associated precision. The instrument correction IC [see Eq. (12.13), for example] is added to distance measurements to obtain the correct distance. It has been shown previously that the instrument correction is a function of a number of independent variables, the most important being distance, temperature and time. The instrument correction is determined for a particular instrument-reflector combination. All distance-dependent and the constant terms require re-evaluation when using the distance meter with another type of reflector.


Citations (11)


... The scale of the survey is controlled by procedure (iii) and the height control of the survey is maintained by procedure (iv). The method used for precisely determining the height of instrument is described by Rüeger and Brunner (1982). The three-dimensional coordinates of the targets are thus obtained by spatial intersection techniques. ...

Reference:

Surveying the deflection of an arch bridge to sub-millimetre precision
EDM-Height Traversing versus Geodetic Leveling
  • Citing Article
  • March 1982

The Canadian Surveyor

... Measuring through an inhomogeneous atmosphere causes both temporally and spatially varying signal delays, resulting in distance biases and temporally and spatially varying curvature of the signal paths between the instrument and the targets, resulting in angle biases. The main effect of the atmosphere on the distance measurement needs to be taken into account by an atmospheric correction [32], which is a scale factor depending on the density and composition of the air. For many practical use cases of total stations, this scale factor can be calculated from the temperature, pressure, and relative humidity with sufficient accuracy using standard formulae [33,34]. ...

Basic Working Principles of Electronic Distance Meters
  • Citing Chapter
  • January 1996

... Once the amount and size of the droplets are known, only position, speed and luminance are missing. Position follows a uniform distribution, as in Garg and Nayar (2007), Manning (1993), Wang and Clifford (1975). When raindrops fall from the sky, their fall speed stabilizes when gravity and friction forces become equal. ...

Propagation of Electromagnetic Waves Through the Atmosphere
  • Citing Chapter
  • January 1996

... Reports indicated that renal injuries caused by venom toxins may be due to direct or indirect effect ( Martins et al., 1998 ). The direct effects are attributed to components of the venom with acute effects on function and organization of renal tissues, while indirect effect may be the result of a toxic action of reactive metabolites or mediators produced in the kidney during envenoming ( Niesink et al., 1996 ). Damage on cells of the liver suggested the venom can induce hepatotoxicity as N. nigricollis venom has been reported to cause hepatic degeneration . ...

Principles and Applications of EDM
  • Citing Chapter
  • January 1996

... The accuracy of EDM depends on two factors; the first, known as internal, is related to each instrument's manufacturing characteristics. The second case found the external factors that are more complex since they depend mainly on the environmental conditions of the medium in which the electromagnetic wave propagates (Rüeger, 1990). According to Brunner (1984), Rüeger (1990), Torge & Müller (2012), and Ogundare & Adekoya (2015), the principal effect that generates the medium is the variation of the propagation velocity of the wave due to mainly density changes in their composition. ...

On the use of inexpensive reflectors in EDM
  • Citing Article
  • September 1990

Australian Surveyor

... Leveling measurements are susceptible to a wide range of systematic error sources, and the first approach to mitigating these errors is to maintain strict adherence to recognized standards and practices during all field surveys (e.g., Federal Geodetic Control Committee, 1984, ch. 3 Level staff scale errors and those due to thermal expansion cannot be eliminated by field practices and so require deterministic corrections (e.g., Craymer et al., 1995;Rüeger, 1997Rüeger, , 2003. The correction parameters for the invar staves employed in our repeat leveling campaign were determined in a laser interferometry calibration at the Geodetic Laboratory of the Technical University of Munich, Germany. ...

Staff errors in and the adjustment of ordinary levelling runs
  • Citing Article
  • March 1997

Australian Surveyor

... Due to the large working range, these reflectors are recommended for observing moving objects, for instance in the framework of reference point determination (Lösler et al. 2018;Matsumoto et al. 2022). Moreover, misaligned standard glass-body prisms systematically distort the polar observations depending on the angle of incidence and must be corrected, as discussed by Rüeger (1978) and Lösler et al. (2013). As cat-eye reflectors are spherical reflectors that reflect the beam parallel to the incident beam on the surface of the rear hemisphere, the angle of incidence does not affect the polar observations. ...

Misalignment of EDM reflectors and its effects
  • Citing Article
  • March 1978

Australian Surveyor

... To modify the normal tripod to a graduated tripod, approximately one meter of the tape should be glued to the side of every single leg of the tripod or using a graduated centering rod for centering the instrument over a station and measure the height of the instrument (HI) see the attached pictures for using a graduated centering rod for setting up the instrument over a ground station and measuring the height of the instrument was designed by Kern of Aarau, Switzer-land (line of sight) ( Abby, D.G., 1965 ;Rüeger, J.M. and Brunner, F.K., 1981). ...

Practical results of EDM-Height traversing
  • Citing Article
  • June 1981

Australian Surveyor

... The relative movements of the target prism at the monitoring points will help to identify the deformation and critical failures zones in advance utilizing the movement of prisms (Fig. 3). Surveying robots are increasingly used for the monitoring of structures and terrains, because they relieve personnel from repetitive around-the-clock measurements [13]. With the availability of long range, high accuracy total stations in the recent years, the monitoring of slope using prisms have almost become a real time solution. ...

Monitoring of an Open Cut Mine with a Surveying Robot
  • Citing Article
  • December 1994

Australian Surveyor