Comparative analysis of quadrature formulas for the mean integral refractive index of air in high-precision ranging

Neyezhmakov, Pavel; Panasenko, T.; Прокопов, Олександр; Shloma, A.; Trevoho, I.

doi:10.33841/1819-1339-1-39-13

Cited by 5 publications

(4 citation statements)

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“…The methodological component of the error of the empirical approach is determined by the difference n acc -n emp of the two results of calculating the value n according to formula (2) (from this difference the corresponding uncertainty component | n acc -n emp |/3 1/2 is estimated). For the first result ( n acc is a rigorous approach), the integral (2) accounting for formula (3) with P and e unchanged along the trace is expressed through integral (4) using the ratio…”

Section: Research Resultsmentioning

confidence: 99%

“…Recently, the requirements for the accuracy of determining the mean integral refractive index of the air have increased significantly. It has led to the rapid development of both methods for direct determination of the atmospheric delay (hardware methods) [1] and indirect determination based on the representation of the integral of the refractive index along the trace of the optical signal using quadrature or interpolation formulas (point approximation methods) [2,3]. The importance of the point approximation methods is that they allow representing the average integral refractive index as a function of the local values of meteorological parameters (pressure P, temperature T and air humidity e) in a few discrete points located along the measured trace.…”

Section: Introductionmentioning

confidence: 99%

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Using the average air temperature along the trace for atmospheric correction in laser ranging: accuracy analysis

Neyezhmakov¹,

Prokopov²

2022

УМЖ

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One of the factors affecting the results of laser ranging measurements on ground-level traces is the difference between the speed of light propagation in the Earth’s atmosphere and the speed of light in vacuum. This difference is accounted for by the introduction of a correction for the mean integral refractive index of air along the measured trace. Research to improve the accuracy of such a correction is one of the most important scientific fields in geodesy and metrology. At the same time, the empirical approach to accounting for the atmospheric influence, which does not have a strict justification, is used in geodetic practice and involves determining the mean integral refractive index by the average air temperature along the measured trace. The paper is dedicated to the analysis of the accuracy of this empirical approach and to the estimation of the possibility of its application for providing traceability in the practice of linear measurements.

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Section: Research Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Using the average air temperature along the trace for atmospheric correction in laser ranging: accuracy analysis

Neyezhmakov¹,

Prokopov²

2022

УМЖ

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“…It seems straightforward to use (ideally ventilated) calibrated temperature sensors distributed along the beam path. We have investigated the performance of several quadrature methods to approximate the exact integral n = 1∕L∫ L 0 n(s)ds by distributed sensors providing point-wise information on the local environment and gradients (Neyezhmakov et al 2020a). For the linear geodetic polygon of the National Scientific Centre "Institute of Metrology" (Kharkiv, Ukraine), a relative uncertainty of 10 -7 can be achieved which will provide a level of uncertainty of 1 mm for baseline 5 km (Neyezhmakov et al 2020b).…”

Section: Environmental Sensing and Compensationmentioning

confidence: 99%

The European GeoMetre project: developing enhanced large-scale dimensional metrology for geodesy

et al. 2023

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We provide a survey on the joint European research project “GeoMetre”, which explores novel technologies and their inclusion to existing surveying strategies to improve the traceability of geodetic reference frames to the SI definition of the metre. This work includes the development of novel distance meters with a range of up to 5 km, the realisation of optical multilateration systems for large structure monitoring at an operation distance of 50 m and beyond, and a novel strategy for GNSS-based distance determination. Different methods for refractivity compensation, based on classical sensors, on dispersion, on spectroscopic thermometry, and on the speed of sound to reduce the meteorological uncertainties in precise distance measurements, are developed further and characterised. These systems are validated at and applied to the novel European standard baseline EURO5000 at the Pieniny Kippen Belt, Poland, which was completely refurbished and intensely studied in this project. We use our novel instruments for a reduced uncertainty of the scale in the surveillance networks solutions for local tie measurements at space-geodetic co-location stations. We also investigate novel approaches like close-range photogrammetry to reference point determination of space-geodetic telescopes. Finally, we also investigate the inclusion of the local gravity field to consider the deviations of the vertical in the data analysis and to reduce the uncertainty of coordinate transformations in this complex problem.

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“…Elaborate sensor networks can mitigate 5 th Joint International Symposium on Deformation Monitoring (JISDM), 20-22 June 2022, Valencia, Spain 2022, Editorial Universitat Politècnica de València this problem, e.g. at reference baselines (Pollinger et al, 2012;Neyezhmakov et al, 2020). Ideally, however, the effective index of refraction is measured in the same volume as the optical beam.…”

Section: Introductionmentioning

confidence: 99%

Two multi-wavelength interferometers for large-scale surveying

Sauthoff

Köchert

Prellinger

et al. 2022

Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022

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Deformation monitoring requires the detection of smallest changes, always at the limits of technical feasibility. Trying to push these limits further, we have realised two terrestrial ranging instruments: a long-range 1D electro-optic distance meter and a 3D multilateration-capable sensor system of 50 m range. The former one is intended as primary standard for the calibration of geodetic instrumentation with low uncertainty to the SI definition of the metre. The latter one is intended for monitoring larger monuments like VLBI antennas. In this contribution, we describe the technical challenges and our solutions for such instrumentation. We use the two-colour method for inline refractive index compensation. As common optical source, we developed a versatile multi-wavelength generator based on two Nd:YAG lasers stabilised by a phase-locked loop realised by Field Programmable Gate Arrays (FPGA). The 1D interferometer uses custom-designed achromatic optics and a mechanical frame optimised for form stability under field conditions. The phase demodulation system allows for maximum range flexibility from several meters up to several kilometres. The base ranging unit of the 3D multilateration system adheres to a different demodulation technique, which allows a relatively simple interferometer head design. This approach requires a sophisticated source modulation scheme limiting the applicability to distances over 15 m up to approximately 50 m in our case.

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Comparative analysis of quadrature formulas for the mean integral refractive index of air in high-precision ranging

Cited by 5 publications

References 0 publications

Using the average air temperature along the trace for atmospheric correction in laser ranging: accuracy analysis

Using the average air temperature along the trace for atmospheric correction in laser ranging: accuracy analysis

The European GeoMetre project: developing enhanced large-scale dimensional metrology for geodesy

Two multi-wavelength interferometers for large-scale surveying

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