Contribution of instrument centring to the uncertainty of a horizontal angle

Ruiz-Armenteros, Antonio M.; Balboa, José Luis García; Mesa-Mingorance, José Luis; Ruiz-Lendínez, Juan José; Ramos, M. I.

doi:10.1179/1752270613y.0000000041

Cited by 5 publications

(3 citation statements)

References 4 publications

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“…Mainly in horizontal angle measurement, this source of uncertainty may have a great effect for short distances, which emphasises the need to set up the instrument carefully. In [ 5 ], different charts are presented with the contribution to the uncertainty of a horizontal angle due to the uncertainty in the instrument centring. As an example, a centring error of 1 mm causes an error of 40 cc (≈ 13′′) in a horizontal angle of 150 grad (= 135°) in sights of 30 m. Because of its importance in the quality of a measure, different authors continue investigating the assessment of this uncertainty [ 4 , 6 , 7 ], the minimization of its influence [ 8 ] or its influence in error models [ 5 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

“…This uncertainty in instrument centring

depends on: (i) the state of the plummet system (mainly optical or laser); (ii) the quality of the tripod; and (iii) the skill of the surveyor [ 11 ]. Many problems involved with instrument centring stem from a careless attitude on the part of the surveyor and especially a failure to test the plummet and ensure that the instrument is carefully levelled [ 5 ]. Some other parameters that influence

are the quality of lighting, the resolution of the observer’s eye, the plummet zoom, and the height of the instrument over the ground target [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

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A Field Procedure for the Assessment of the Centring Uncertainty of Geodetic and Surveying Instruments

Balboa

Ruiz-Armenteros

Avi

et al. 2018

Sensors

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The uncertainty evaluation of survey measurements is a daily and essential task in any surveying work. The result of a measurement is, in fact, only complete when accompanied by a statement of its uncertainty. Miscentring, or centring error, is one of the sources of uncertainty in every basic survey measurement which may have a great effect on horizontal angle measurement for short distances. In the literature, different terms and values are considered to refer to this source of uncertainty. Standard ISO 17123 provides different procedures for assessing the measurement uncertainty of geodetic and surveying instruments, with the aim of checking their suitability for the intending and immediate task in field conditions. ISO 17123 is aware of the importance of uncertainty in the instrument centring, but it does not propose any standardised procedure for its assessment. In this study, we propose such a procedure following a Type A evaluation (through the statistical analysis of series of observations), avoiding using values from Type B evaluations (from manufacturer’s specifications, handbooks, personal experiences, etc.) that could be unsuitable for the conditions of the task. Uncertainty can be individualised for a particular instrument (which includes the plummet type), ground mark, operator, and other factors on which the results could be dependent. The testing methodology includes a configuration of the test field, measurements, and calculation, following the structure of each part of the standard ISO 17123. An experimental application is included with two different total stations, which also includes a statistical analysis of the results.

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Section: Introductionmentioning

confidence: 99%

“…This uncertainty in instrument centring

are the quality of lighting, the resolution of the observer’s eye, the plummet zoom, and the height of the instrument over the ground target [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

A Field Procedure for the Assessment of the Centring Uncertainty of Geodetic and Surveying Instruments

Balboa

Ruiz-Armenteros

Avi

et al. 2018

Sensors

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“…= + Δ = + ⋅ sin and (4) Literature (let us name only a few sources: [5][6][7][8][9][10]) deals with the influence of the displacement of the signalized points (in our case, the displacement of points and ) and the influence of the centering error (in our example, the displacement of point ) on the measured horizontal angles; in our paper, we will discuss the influence of these displacements on the position of the control point, i.e., on the coordinates of the control point.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Pillar Displacements on Geodetic Measurements

et al. 2020

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This paper deals with the effects that displacements of the measuring pillar have on precise geodetic measurements. The changes in the position of the control points on the object or its surroundings can only be determined with well stabilized and stable reference points. These points are usually stabilized with measuring pillars which are not always constructed in an optimal manner. If they are placed in a dark tube with a high absorption factor, solar heating on one side of the pillar can cause the pillar to deflect considerably due to the temperature difference on the two sides of the pillar. This paper presents the influence of such a displacement, if the pillar is a survey point, orientation point, or control point. We show that even small displacement of the survey point can have important influence on all measurements and that the error in some cases significantly increases, e.g., if the standard deviations of the coordinates of the survey point are 1 mm and their covariance is assumed to be zero, the standard deviation of the distance between measured and exact position of the control point exceeds the value of 2.2 mm.

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Analysis of using the modified centring plates with eccentric points for geodetic measurements

Kwinta,

Gargula

2023

Appl Geomat

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Many engineering structures require high measurement accuracy. Their displacement and deformation are determined from the results of special measurements. For the measurements to be accurate, a properly constructed and marked survey network is necessary. The long-term stability of survey points can be ensured by marking (installing) them on solid rock or special triangulation pillars. Accurate and repeatable instrument positioning and premarking over the points is ensured by centring plates. Centring plates with eccentric points can be used when a survey involves several instruments. The article presents the results of measurements and computations done using centring plates with eccentric points. The measurements were conducted in a metrology laboratory. The sought points were premarked with prisms and reflective targets. The measuring methods were angular intersection, linear intersection, and linear-angular measurements. We computed coordinates for the measured points, and the results were compared to their known directory values. The results demonstrate that centring plates with eccentric points can be employed in engineering surveys.

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Contribution of instrument centring to the uncertainty of a horizontal angle

Cited by 5 publications

References 4 publications

A Field Procedure for the Assessment of the Centring Uncertainty of Geodetic and Surveying Instruments

A Field Procedure for the Assessment of the Centring Uncertainty of Geodetic and Surveying Instruments

The Influence of Pillar Displacements on Geodetic Measurements

Analysis of using the modified centring plates with eccentric points for geodetic measurements

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