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Number of results: 54
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Abstract

This paper presents a method of correcting the effects caused by refraction phenomena in an optical measurement system. The correction algorithm proposed can be applied in many different photogrammetric applications affected by these effects. To validate this algorithm, a foot sole optical measurement system that uses several cameras to build a mesh of a foot sole has been used. This measurement system has six cameras that are protected by a safety glass that separates the cameras from the foot to be measured. The safety glass produces an air-glass-air interface that causes the refraction phenomena, producing deformations in the images. Due to the deformations it is impossible to obtain reliable metric information of the images captured using the measurement system. The developed correction algorithm is based on a grid layout and associated polynomials and makes it possible to correct the deformations and extract accurate metric information.

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Authors and Affiliations

David Samper
Jorge Santolaria
Ana Cristina Majarena
Juan José Aguilar
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Abstract

In the article a non-uniformity correction method is presented which allows to compensate for the influence of detector’s temperature drift. For this purpose, dependency between output signal value and the temperature of the detector array was investigated. Additionally the influence of the temperature on the Offset and Gain coefficients was measured. Presented method utilizes estimated dependency between output signal of detectors and their temperature. In the presented method, the shutter is used for establishing signal reference. Thermoelectric cooler is used for changing the temperature of the detector array.

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Authors and Affiliations

Michał Krupiński
Grzegorz Bieszczad
Tomasz Sosnowski
Henryk Madura
Sławomir Gogler
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Abstract

In the second part of the article, the history of standardization programmes concerning the names of physiographic objects is discussed. The basis of the standardization programme currently followed by the Commission on Names of Localities and Physiographic Objects is described. The paper also presents the criteria of linguistic correctness adopted by the previous standardization commissions as well as by the present one. Issues of linguistic correctness of geographical names with dialectal properties and of names borrowed from minority languages are discussed. Attention is paid to some structural discrepancies in the approaches to the issue of correctness taken by the Commission on Names of Localities and Physiographic Objects and by local authorities.

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Authors and Affiliations

Ewa Wolnicz-Pawłowska
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Abstract

The use of a network of reference stations instead of a single reference station allows to model some systematic errors in a region, and to increase the operational distance between the rover and reference stations. Permanent GPS reference stations exist in many countries, and GPS observations are available for the users in real-time mode and in post-processing. The paper presents DGPS post-processing positioning with the use of three reference stations. The traditional DGPS technique is based on one reference station. It has been shown that the accuracy of such positioning is about 1-2 meters, depending on the number of satellites being tracked and the resulting value of POOP (Position Dilution of Precision). The accuracy of DGPS positioning degrades when the distance between the rover and the base station increases. The paper shows that when three reference stations are used simultaneously, pseudorange corrections for a virtual reference station, located in the vicinity of an unknown station can be created, and distribution of pseudorange corrections over time can be analysed and modelled. Three reference stations give redundant observations and enable to reduce some measurement errors and biases. Practical calculations and analysis of accuracy have been presented for medium-long and long distances between the rover and reference stations.
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Authors and Affiliations

Mieczysław Bakuła
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Abstract

When conducting geodetic and gravimetric measurements, there is a problem of projecting them to the reference surface. Since the gravitational field is inhomogeneous under the real conditions, the problem arises of determining the corrections to the measured values of gravitational acceleration in order to use the obtained data for the subsequent solutions of projection problems. Currently, the solution to this problem is performed using a Bouguer reduction, which requires information about the internal structure of the upper layer of the earth’s surface, topography, etc. The purpose of this study is to develop a methodological approach that would allow to determine the reduction (projection) corrections for gravitational acceleration on technogenic and geodynamic polygons without using data about the distribution of surface layer density and topography. The research process is based on the use of mathematical analysis methods and a wide range of experimental geodetic and gravimetric measurements. In the course of the performed researches, an algorithm was obtained and a practical implementation of the determination of the corrections in the measured values of gravitational acceleration on the basis of geodetic and gravimetric measurements was carried out at the certain geodynamic polygon in order to bring all corrections to one level surface.

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Authors and Affiliations

Lev Perovych
Igor Perovych
Valeriy Gorlachuk
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Abstract

A simplified isoperibol calorimetry method for measuring specific heat in solids is described. Taking advantage of the classical Nernst dependency the specific heat is calculated from time-domain temperature curves registered for a sample forced heating and natural cooling phase. In order to improve accuracy of the measurements a correction factor, taking into account the heat transferred to the surrounding, is introduced along with a procedure of statistical elimination of unavoidable measurement deviations. The method is implemented in a simple and straightforward measuring system involving no vacuum calorimeter. The method is applicable for quick and routine specific heat measurements performed on small solid dielectric or metallic specimens at near-room temperature. Test results of various materials used commonly in electrical engineering are demonstrated and discussed as well as comparison to drop calorimetry and differential scanning calorimetry reference measurements is included. The overall repeatability of the test method and the simplified apparatus is estimated as not worse than 2.6%.
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Authors and Affiliations

Leszek Moroń
Paweł Żyłka
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Abstract

A high pressure resonator transducer (0 to 100 MPa) devised by the author has been described. The elastic element of the converter consists of a cylinder with an offset arranged axis hole. Quartz resonators were used for the measurement of deformations of the pipe. Based upon the results of the transducer testing, a new algorithmic method for the minimizalizsation of the temperature error, that eliminates the need for a temperature gauge has been worked out.

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Authors and Affiliations

Krzysztof Tomczuk
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Abstract

Qualitative and quantitative results of high terrain elevation effect on spectral radiance of optical satellite image which affect the accuracy in retrieving of land surface cover changes is given. The paper includes two main parts: correction model of spectral radiance of satellite image affected by high terrain elevation and assessment of impacts and variation of land cover changes before and after correcting influence of high terrain elevation to the spectral radiance of the image. Study has been carried out with SPOT 5 in Hoa Binh mountain area of two periods: 2007 and 2010. Results showed that appropriate correction model is the Meyer’s one. The impacts of correction spectral radiance to 7 classes of classified images fluctuate from 15% to 400%. The varying changes before and after correction of image radiation fluctuate over 7 classes from 5% to 100%.
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Authors and Affiliations

Luong Chinh Ke
Tran Ngoc Tuong
Nguyen Van Hung
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Abstract

The accuracy of computed terrain corrections might be an important issue when modelling precise gravimetric geoid, especially for evaluating the quality of geoid model developed. It depends on the accuracy of heights and positions of gravity points used and on the quality of digital terrain model applied. The work presents the attempts towards the estimation of the effect of uncertainty in height and position of gravity points as well as uncertainty of digital terrain model on the accuracy of computed terrain corrections. Analytical formulae for the respective error propagation were developed and they were supported, when needed, by numerical evaluations. Propagation of height data errors on calculated terrain corrections was independently conducted purely numerically. Numerical calculations were performed with the use of data from gravity database for Poland and digital terrain models DTED2 and SRTM3. The results obtained using analytical estimation are compatible with the respective ones obtained using pure numerical estimation. The terrain correction error resulting from the errors in input data generally does not exceed I mGal for Poland. The estimated accuracy of terrain corrections computed using height data available for Poland is sufficient for modelling gravimetric geoid with a centimetre accuracy.
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Authors and Affiliations

Małgorzata Szelachowska
Jan Kryński
ORCID: ORCID
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Abstract

Despite the large number of studies conducted on teachers’ oral corrective feedback, the findings of these studies have been mainly limited to cognitive orientations rooted in experimental designs and the verbal discourse of the teacher as the main object of inquiry. Considering teachers’ affective concerns regarding their corrective feedback and the shift from negative psychology to positive psychology in the field of second/foreign language teaching as well as the entirety of the teacher’s corrective repertoire, in this case study, we aimed to explore the enjoyment building capacity of a teacher’s multimodal corrective feedback in a university general English course. We video-recorded the teacher’s multimodal corrective feedback including verbal and nonverbal semiotic resources like gesture, gaze, and posture while observing the learners’ emotional experiences for eight sessions. We also conducted stimulated recall interviews with some learners and collected their written journals about the experiences of enjoyment with regard to the teacher’s multimodal corrective feedback scenarios. The teacher’s multimodal corrective feedback was analyzed through systemic functional multimodal discourse analysis (SF-MDA) and the content of the interview transcripts as well as the written journals were qualitatively analyzed. The findings indicated that the teacher’s inherent multimodality in his corrective feedback broadened the main dimensions of enjoyment by raising the learners’ attention to their errors, heightening their focus on the correct form, and increasing the salience of his corrective feedback. Further arguments regarding the findings are discussed.

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Authors and Affiliations

Mokarrameh Bayat
Majid Elahi Shirvan
ORCID: ORCID
Elyas Barabadi
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Abstract

Correctional staff is particularly exposed to occupational stress which in turn can have a negative impact on their job performance. This study attempted to analyse the role of personality, organizational factors, and stress coping strategies in shaping job satisfaction. 163 correctional staff members who were being trained at the Central Training Centre of Correctional Services in Kalisz, Poland, participated in the study. The following tools were used: The Bochum Inventory of Personal Work Features (BIP), the Multiphasic Inventory for Measuring Coping (COPE), and the Satisfaction with Job Scale (SSP).

Staff working directly with inmates scored the lowest in terms of job satisfaction. Social sensibility is a predictor of job satisfaction among each study subgroup and each correctional department and correctional staff as a whole. Correlates of job satisfaction among correctional officers were: Active coping with stressful situations and Seeking social support for emotional and instrumental reasons.

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Authors and Affiliations

Ewa Sygit-Kowalkowska
Robert Poklek
Beata Pastwa-Wojciechowska
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Abstract

One of the most critical factors which determine the accuracy of deformation maps provided by Differential Synthetic Aperture Radar Interferometry (DInSAR) are atmospheric artefacts. Nowadays, one of the most popular approaches to minimize atmospheric artefacts is Generic Atmospheric Correction Online Service for InSAR (GACOS). Nevertheless, in the literature, the authors reported various effects of GACOS correction on the deformation estimates in different study areas Therefore, this paper aims to assess the effect of GACOS correction on the accuracy of DInSAR-based deformation monitoring in USCB by using Sentinel-1 data. For the accuracy evaluation, eight Global Navigation Satellite Systems (GNSS) permanent stations, as well as five low-cost GNSS receivers were utilized. GACOS-based DInSAR products were evaluated for: (1) single interferograms in different geometries; (2) cumulative deformation maps in various geometries and (3) decomposed results delivered from GACOS-based DInSAR measurements. Generally, based on the achieved results, GACOS correction had a positive effect on the accuracy of the deformation estimates in USCB by using DInSAR approach and Sentinel-1 data in each before mentioned aspect. When considering (1), it was possible to achieve Root Mean Square Error (RMSE) below 1 cm for a single interferogram for only 20% and 26% of the ascending and descending investigated interferograms, respectively when compared with GNSS measurements. The RMSE below 2 cm was achieved by 47% and 66% of the descending and ascending interferograms, respectively.
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Bibliography

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Authors and Affiliations

Kamila Pawłuszek-Filipiak
1
ORCID: ORCID
Natalia Wielgocka
1
ORCID: ORCID
Tymon Lewandowski
1
ORCID: ORCID
Damian Tondaś
1
ORCID: ORCID

  1. Wroclaw University of Environmental and Life Science, Wroclaw, Poland
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Abstract

The reflection coefficient of the open end belongs among the essential parameters in the physical description of a flue organ pipe. It leads directly to practical topics such as the pipe scaling. In this article, sound propagation is investigated inside an organ pipe with the most intense mean flow that is achievable under musically relevant conditions. A theoretical model is tested against the experimental data to obtain a suitable formula for the reflection coefficient when a non-negligible flow through the open end is considered. The velocity profile is examined by means of particle image velocimetry. A fully developed turbulent profile is found and interactions of the acoustic boundary layer with the turbulent internal flow are discussed. A higher value of the end correction than expected from the classical result of Levine and Schwinger is found, but this feature shall be associated with the pipe wall thickness rather than the mean flow effects.
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Bibliography

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Authors and Affiliations

Viktor Hruška
1
Pavel Dlask
1

  1. Academy of Performing Arts in Prague, Musical Acoustics Research Centre, Prague, Czech Republic
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Abstract

The main purpose of this paper is to reconstruct the approach to ambiguity presented in Tadeusz Pawłowski’s work Tworzenie pojęć w naukach humanistycznych („Creating concepts in the humanities”) (1986), to systematize and analyze this conception. Due to the fact that Pawłowski was a student of Tadeusz Kotarbiński and Janina Kotarbińska, and that he dealt with methodological issues concerning the language of science (and scientific philosophy), the background of my considerations is the tradition of the Lvov‑Warsaw School. In the article I also formulate some remarks on Pawłowski’s conception, as well as some other observations on ambiguity.
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Authors and Affiliations

Alicja Chybińska
1
ORCID: ORCID

  1. Uniwersytet Warszawski, Wydział Filozofii, ul. Krakowskie Przedmieście 3, 00-927 Warszawa
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Abstract

The aim of this paper is to compare the efficiency of various outlier correction methods for ECG signal processing in biometric applications. The main idea is to correct anomalies in various segments of ECG waveform rather than skipping a corrupted ECG heartbeat in order to achieve better statistics. Experiments were performed using a self-collected Lviv Biometric Dataset. This database contains over 1400 records for 95 unique persons. The baseline identification accuracy without any correction is around 86%. After applying the outlier correction the results were improved up to 98% for autoencoder based algorithms and up to 97.1% for sliding Euclidean window. Adding outlier correction stage in the biometric identification process results in increased processing time (up to 20%), however, it is not critical in the most use-cases.

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Authors and Affiliations

Su Jun
Miroslaw Szmajda
Volodymyr Khoma
Yuriy Khoma
Dmytro Sabodashko
Orest Kochan
Jinfei Wang
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Abstract

Low-cost Micro-Electromechanical System (MEMS) gyroscopes are known to have a smaller size, lower weight, and less power consumption than their more technologically advanced counterparts. However, current low-grade MEMS gyroscopes have poor performance and cannot compete with quality sensors in high accuracy navigational and guidance applications. The main focus of this paper is to investigate performance improvements by fusing multiple homogeneous MEMS gyroscopes. These gyros are transformed into a virtual gyro using a feedback weighted fusion algorithm with dynamic sensor bias correction. The gyroscope array combines eight homogeneous gyroscope units on each axis and divides them into two layers of differential configuration. The algorithm uses the gyroscope array estimation value to remove the gyroscope bias and then correct the gyroscope array measurement value. Then the gyroscope variance is recalculated in real time according to the revised measurement value and the weighted coefficients and state estimation of each gyroscope are deduced according to the least square principle. The simulations and experiments showed that the proposed algorithm could further reduce the drift and improve the overall accuracy beyond the performance limitations of individual gyroscopes. The maximum cumulative angle error was - 2:09 degrees after 2000 seconds in the static test, and the standard deviation (STD) of the output fusion value of the proposed algorithm was 0.006 degrees/s in the dynamic test, which was only 1.7% of the STD value of an individual gyroscope.
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Authors and Affiliations

Ding Yuan
1
Yongyuan Qin
1
Xiaowei Shen
2
Zongwei Wu
2

  1. School of Automation, Northwestern Polytechnical University, Xi’an 710129, China
  2. Xi’an Research Institute of High Technology, Hongqing Town, Xi’an 710025, China
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Abstract

In the article we address matters related to the stability of motion of the car subjected to the external lateral force. We show the possibility to compensate the effect of the external forces my means of the steering wheel angle. We have carried out the analysis for bicycle scheme vehicle and four-wheel model according to linear and nonlinear drift hypothesis. We have considered influence of speed of the car and size of external side force for the period of transition processes of stabilization of the movement.
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Authors and Affiliations

V. Verbitskii
R. Kuliev
K. Kravchenko
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Abstract

This paper addresses the issue of obtaining maximum likelihood estimates of parameters for structural VAR models with a mixture of distributions. Hence the problem does not have a closed form solution, numerical optimization procedures need to be used. A Monte Carlo experiment is designed to compare the performance of four maximization algorithms and two estimation strategies. It is shown that the EM algorithm outperforms the general maximization algorithms such as BFGS, NEWTON and BHHH. Moreover, simplification of the problem introduced in the two steps quasi ML method does not worsen small sample properties of the estimators and therefore may be recommended in the empirical analysis.

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Katarzyna Maciejowska
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Abstract

The aim of the study is to discuss the relationship of the crude oil price, speculative activity and fundamental factors. An empirical study was conducted with a VEC model. Two cointegrating vectors were identified. The first vector represents the speculative activity. We argue that the number of short non-commercial positions increases with the crude oil stock and price, decreases with the higher number of long non-commercial positions. A positive trend of crude oil prices may be a signal for traders outside the industry to invest in the oil market, especially as access to information could be limited for them. The second vector represents the crude oil price under the fundamental approach. The results support the hypothesis that the crude oil price is dependent on futures trading. The higher is a number of commercial long positions, the greater is the pressure on crude oil price to increase.

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Authors and Affiliations

Robert Socha
Piotr Wdowiński
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Abstract

The paper addresses the problem of the automatic distortion removal from images acquired with non-metric SLR camera equipped with prime lenses. From the photogrammetric point of view the following question arises: is the accuracy of distortion control data provided by the manufacturer for a certain lens model (not item) sufficient in order to achieve demanded accuracy? In order to obtain the reliable answer to the aforementioned problem the two kinds of tests were carried out for three lens models. Firstly the multi-variant camera calibration was conducted using the software providing full accuracy analysis. Secondly the accuracy analysis using check points took place. The check points were measured in the images resampled based on estimated distortion model or in distortion-free images simply acquired in the automatic distortion removal mode. The extensive conclusions regarding application of each calibration approach in practice are given. Finally the rules of applying automatic distortion removal in photogrammetric measurements are suggested
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Authors and Affiliations

Jakub Kolecki
Antoni Rzonca
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Abstract

In this paper, the power factor correction system consisted of: bridge converter, parallel resonant circuit, high frequency transformer, diode rectifier and LFCF filter is presented. This system is controlled by a pulse density modulation method and the principle of its operation is based on the boost technique. The modeling approach is illustrated by an example using AC/HF/DC converter. Verification of the derived model is provided, which demonstrated the validity of the proposed approach.
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Authors and Affiliations

Antoni Bogdan
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Abstract

The main topic of this study is the experimental measurement and mathematical modelling of global gas hold-up and bubble size distribution in an aerated stirred vessel using the population balance method. The air-water system consisted of a mixing tank of diameter T = 0.29 m, which was equipped with a six-bladed Rushton turbine. Calculations were performed with CFD software CFX 14.5. Turbulent quantities were predicted using the standard k-ε turbulence model. Coalescence and breakup of bubbles were modelled using the homogeneous MUSIG method with 24 bubble size groups. To achieve a better prediction of the turbulent quantities, simulations were performed with much finer meshes than those that have been adopted so far for bubble size distribution modelling. Several different drag coefficient correlations were implemented in the solver, and their influence on the results was studied. Turbulent drag correction to reduce the bubble slip velocity proved to be essential to achieve agreement of the simulated gas distribution with experiments. To model the disintegration of bubbles, the widely adopted breakup model by Luo & Svendsen was used. However, its applicability was questioned.

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Authors and Affiliations

Zbyněk Kálal
Milan Jahoda
Ivan Fořt
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Abstract

The paper presents definitions and relative measures of the system sensitivity and sensitivity of its errors. The model of a real system and model of an ideal measuring system were introduced. It allows to determine the errors of the system. The paper presents also how to use the error sensitivity analysis carried out on the models of the measuring system to the correction of the nonlinearity error of its static characteristic. The corrective function is determined as a relation between the input variable of the tested system and its chosen parameter. The use of the proposed method has been presented on the example of a phase angle modulator. The obtained results have been compared with the results of analytic calculations. The idea of a phase angle modulator is also presented.

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Authors and Affiliations

Ryszard Sroka
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Abstract

This paper presents two methods for evaluation of the effective wavenumber of nearly-Gaussian beams in laser interferometers that can be used for determination of a so called diffraction correction in absolute gravimeters. The first method, that can be simply used in situ, is an empirical procedure based on the evaluation of the variability of g measurements against the amount of light limited by an iris diaphragm and transmitted to a photodetector. However, precision of this method depends on the beam quality similarly as in the case of the conventional method based on measurement of a beam width. The second method, that is more complex, is based on beam profiling in various distances and on calculation of the effective wavenumber using the second spatial derivative of a non-ideal beam field envelope. The measurement results achieved by both methods are presented on an example of two absolute gravimeters and the determined diffraction corrections are compared with the results obtained by measurements of beam width. Agreement of methods within about 1 mGal have been obtained with average diffraction corrections slightly exceeding +2 mGal for three FG5(X) gravimeter configurations.

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Bibliography

References

[1]Monchalin, J.P., Kelly, M.J., Thomas, J.E., Kurnit, N.A., Szöke, A., Zernike, F., Lee, P.H., Javan, A.(1981). Accurate laser wavelength measurement with a precision two-beam scanning Michelson in-terferometer.Appl Opt., 20(5), 736–57.

[2]Sasso, C.P., Massa, E., and Mana, G. (2016). Diffraction effects in length measurements by laserinterferometry.Optics Express, 24(6), 6522–6531. DOI: 10.1364/OE.24.006522

[3]Niebauer, T.M., Sasagawa, G.S., Faller, J.E., Hilt, R., Klopping, F. (1995). A new generation of abso-lute gravimeters.Metrologia, 32, 159–180.

[4]vanWestrum, D., Niebauer, T.M. (2003). The diffraction correction for absolute gravimeters.Metrologia, 40, 258–263.

[5]Robertsson, L. (2007). On the diffraction correction in absolute gravimetry.Metrologia, 44, 35–39.

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Authors and Affiliations

Petr Křen
Vojtech Pálinkáš

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