Evaluation of the Credibility of Reflectorless Distance Measurement

Lambrou, E.; Pantazis, George

doi:10.1061/(asce)su.1943-5428.0000029

Cited by 19 publications

(12 citation statements)

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“…The acceptable value of ΔD is given by the Equation (2) [5] for the desired confidence level (x) Tables 1-10. The symbol (------) means that the instrument did not measure the distance to the target.…”

Section: Resultsmentioning

confidence: 99%

“…In order to ascertain the accuracy of the RLTS at short range distances, several studies were carried out. The accuracy of RTLS was investigated by [9] for distances up to 100 m, by [2] for distances up to 300 feet (≅90 m), by [12] for distances up to 60 m and by [5] for distances up to 50 m. This paper studies the effect of target material, target size and incidence angle of laser beam on the accuracy of reflectorless measurements for distances up to 1000 m. A series of experimental measurements for 10 different distances were carried out using targets of 6 different materials and 4 different sizes at 5 different incidence angles. The distances obtained by reflectorless surveys were compared to the distances obtained by prism surveys.…”

Section: Introductionmentioning

confidence: 99%

“…It is also used in building construction layout [2], dynamic deformation of bridges [3], cultural heritage documentation [4] and many other engineering applications. In the 1990s, a powerful visible laser beam was used for measurements to almost any surface without the use of retroprisms [5]. Many of today's total stations have integrated this reflectorless EDM technology [6].…”

Section: Introductionmentioning

confidence: 99%

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Accuracy Evaluation of Long-Range Reflectorless Distance Measurement

Khalil¹

2015

POS

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Reflectorless total station (RLTS) has made it possible for only one person to carry out field measurements and inaccessible points can be measured with relative ease. There is no sufficient information about the accuracy of these instruments for the long range measurements. This paper attempts to evaluate the accuracy of reflectorless distance measurements ranging up to 1000 m and to determine the surface area needed for such measurements at different incidence angles. An experiment was carried out to examine what effect surface material, target size and incidence angle had on distance measurement. In this experiment 10 different distances were measured using targets of 6 different materials and 4 different sizes at 5 different incidence angles. To properly evaluate the results, a special supporting base was designed and manufactured for holding the reflecting targets to ensure accuracy in the evaluation. Based on the accuracy analysis of a lot of testing results, the conclusions that were drawn indicated that the target size had a great effect on the accuracy if the incidence angle was between 15˚ and 30˚.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Accuracy Evaluation of Long-Range Reflectorless Distance Measurement

Khalil¹

2015

POS

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“…Also, this research showed that increasing inclining angle leads to increase of distance measurement error. Research for the accuracy of distances measured by reflectorless technology in the range of 50 m resulted by conclusion that correct measurement fluctuates between 20% and 85%, which means that reflectorless technology needs improvement [11]. The long-range reflectorless distance (up to 1000 m) measurements show that the accuracy is dependent on the incidence angle and that the size of target shall increase with distance [12].…”

Section: Introductionmentioning

confidence: 99%

Accuracy of Reflectorless Technology for Distance Measurements in Practice

Nestorović¹,

Kuburić

Trifković

et al. 2021

Teh. vjesn.

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Utilization of reflectorless technology for distance measurements is very useful in surveying practice and improves efficiency of geodetic measurements. Some experience, however, has shown that measurements of distance by utilization of reflectorless technology could differ more than expected. In this research, the main aim was to find out if the accuracy and reliability of measured distances by reflectorless technology are on the acceptable level for determination position of the points i.e. their coordinates. Common characteristic of investigated accuracy of distances obtained by reflectorless technology in literature is careful design of experiments and controlled conditions, but in practice it is not the case. That is the reason for designing the experiment, which reflects the conditions as near as possible to the real conditions in practice. The surfaces for measurement were divided into two groups: regular and irregular and differences of distances obtained by reflectorless measurements were investigated in the case of manual and automated sighting. Obtained results show that distances, when measured by using reflectorless technology in only one position of telescope, could not be reliable while the average value of measurements obtained in two positions of telescope are of higher accuracy especially for the longer distances.

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“…±0.0003 grads(Lambrou and Pantazis, 2010). Classical methods of surveying (tacheometric) were implemented by observing the shell of the cooling tower in 20 vertical and horizontal point strips through a commonly used 3D polar method (re ectorless distance measurement).…”

mentioning

confidence: 99%

Measurement point density and measurement methods in determining the geometric imperfections of shell surfaces

Kocierz

Rębisz

Ortyl

2018

Reports on Geodesy and Geoinformatics

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In geodetic measurements of deformations in shell cooling towers, an important factor is to optimize the number of points representing the exterior surface of the shell. The conducted analyses of damage to such structures proved that cooling towers exhibited shell deformation consisting of irregular vertical waves (three concavities and two convexities), as well as seven horizontal waves. On this basis, it is claimed that, in accordance with the Shannon theorem, the correct representation of the generated waves requires the measurement of the cooling tower shell in a minimum of 12 vertical and 14 horizontal sections. Such density of the points may not be sufficient to represent local imperfections of the shell. The article presents the results of test measurements and their analysis, which were conducted to verify the assumptions as to the optimal number of measurement points for the shell of a cooling tower. The evaluation was based on a comparative analysis of the data obtained by the Terrestrial Laser Scanning (TLS) method, creating a very detailed model of geometric imperfections in an actual cooling tower with a height of 100 m. Based on the data obtained by the TLS method, point grids of various density were generated. An additional measurement of the cooling tower shell deformation was performed using a precise electronic total station with reflectorless measurement option. Therefore, it was possible to assess the accuracy of measurements by laser scanning in relation to measurements obtained by reflectorless total stations.

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Evaluation of the Credibility of Reflectorless Distance Measurement

Cited by 19 publications

References 1 publication

Accuracy Evaluation of Long-Range Reflectorless Distance Measurement

Accuracy Evaluation of Long-Range Reflectorless Distance Measurement

Accuracy of Reflectorless Technology for Distance Measurements in Practice

Measurement point density and measurement methods in determining the geometric imperfections of shell surfaces

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