9.6 - A dual wavelength optical distance measuring instrument which corrects for air density

Earnshaw, K. B.; Owens, James C.

doi:10.1109/jqe.1967.1074403

Cited by 40 publications

(13 citation statements)

References 5 publications

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“…The method is based on the dispersive characteristic of air in the visible region of the spectrum, which causes two optical signals of different wavelengths to propagate over the same path at slightly different velocities. Several authors have described the application of two-wavelength techniques [Wood and Thompson, 1969;Owens and Earnshaw, 1966;Earnshaw and Owens, 1967;Earnshaw and Hernandez, 1972;Hernandez and Earnshaw, 1972;Bouricius and Earnshaw, 1974]. The major noninstrumental source of error in the two-wavelength systems is uncertainty in the water vapor concentration along the path.…”

Section: Introductionmentioning

confidence: 99%

A multiwavelength distance-measuring instrument for geophysical experiments

Slater¹,

Huggett²

1976

J. Geophys. Res.

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A multiwavelength distance-measuring (MWDM) instrument that utilizes the dispersive nature of the atmosphere has been developed and tested. With this instrument there is no need for the usual meteorological observations and corrections. This MWDM instrument simultaneously measures the optical path length at three wavek/ngths, two in the optical region of the spectrum and one in the microwave region. The instrument calculates correction terms from the optical path length differences and then computes the corrected base line distance, the first-order effects of temperature, pressure, and water vapor fluctuations along the line thus being eliminated. Field testing demonstrated that the instrument was capable of making consecutive distance determinations with a standard deviation from the mean as small as 4 parts in l0 s. The long-term stability of the instrument was investigated from June 1974 to November 1974. The results showed a standard deviation of 1.3 parts in 107 when the data were fit to a sine wave of annual periodicity. The amplitude of this sine wave was 3 parts in 107, which was in good agreement with the predicted results of a two-dimensional t, hermoelastic model. o d c• i I ß ß ß ß ß ß ß 'l ß ß ß ß ß l' ß ß I. ß ß ß e e ß ß ß '.l ß ß ß ß ß .I t (•u •u) 30NV.L$10 SLATER AND HUGGETT: A MWDM INSTRUMENT

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Section: Introductionmentioning

confidence: 99%

A multiwavelength distance-measuring instrument for geophysical experiments

Slater¹,

Huggett²

1976

J. Geophys. Res.

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“…Therefore, if a distance is measured by at least two optical wavelengths, the geometric length can be derived from these observations without the need of environmental observations. This concept was originally proposed in the 1960s (Earnshaw and Owens 1967) and refined by Abou-Zeid in 2008. In 1975, Hugget and Slater presented a first out-door capable electronic distance meter based on this principle, a predecessor of the renowned Terrameter (Huggest and Slater 1975;Huggett 1981).…”

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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“…Des solutions sur la base de la connaissance de la dispersion chromatique de l'indice de l'air ont déjà été proposées dans le passé [25] …”

Section: Conclusion Et Perspectivesunclassified

Un télémètre transportable de résolution submicrométrique

Azouigui¹,

Badr²,

Juncar³

et al. 2015

R. franç. métrol.

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RésuméNous décrivons dans cet article la réalisation d'un télémètre transportable basé sur un principe d'interférométrie à longueur d'onde synthétique. Les sources lasers utilisées sont deux lasers YAG à 532 nm doublés en fréquence. Une technique de détection superhétérodyne a été mise en place pour réaliser une mesure de phase à 2π/5 600 près. Une exactitude d'environ 5 μm (1σ) a été mesurée sur 25 m, par comparaison avec un banc de déplacement interférométrique. Le système a été transporté en Finlande (Nummela) pour mesurer une ligne géodésique de référence, avec une incertitude type de 700 μm. Ce travail s'est fait dans le cadre du projet européen (JRP de l'EMRP) « Long distance » qui s'est achevé en juin 2011.

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9.6 - A dual wavelength optical distance measuring instrument which corrects for air density

Cited by 40 publications

References 5 publications

A multiwavelength distance-measuring instrument for geophysical experiments

A multiwavelength distance-measuring instrument for geophysical experiments

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

Un télémètre transportable de résolution submicrométrique

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