Spectroscopic thermometry for long-distance surveying

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)

Abstract

Electronic distance meters are routinely used to accurately determine the distance between two points. To reach relative measurement uncertainties of 10-7, the average temperature along the beam has to be known within 100 mK since it is a key component in determining the refractive index of air. Temperature measurements at this level are extremely challenging over long distances and especially in an outdoor environment. This paper presents a thermometer for accurate temperature measurements over distances up to a few km. The thermometer is based on direct laser absorption spectroscopy of oxygen near 770 nm. The thermometer yields a spatially continuous measurement of air temperature, and it can provide spatially and temporally well-matching data with an actual distance-measuring laser beam. A field measurement campaign at the 864-m Nummela standard baseline demonstrates applicability of the developed thermometer for improving the refractive index compensation of current high-performance electronic distance meters.
Original languageEnglish
Pages (from-to)239-246
Number of pages8
JournalApplied Optics
Volume56
Issue number2
DOIs
Publication statusPublished - 10 Jan 2017
MoE publication typeA1 Journal article-refereed

Fingerprint

Thermometers
Surveying
temperature measurement
thermometers
Temperature measurement
Refractive index
Laser spectroscopy
Air
Absorption spectroscopy
refractivity
Laser beams
air
laser spectroscopy
electronics
Temperature
Oxygen
high current
absorption spectroscopy
laser beams
temperature

Keywords

  • absorption spectroscopy
  • laser beams
  • refractive index
  • temperature measurement
  • thermometers
  • air temperature
  • continuous measurements
  • electronic distance meters
  • field measurement
  • laser absorption spectroscopy
  • outdoor environment
  • refractive index of air
  • relative measurement

Cite this

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title = "Spectroscopic thermometry for long-distance surveying",
abstract = "Electronic distance meters are routinely used to accurately determine the distance between two points. To reach relative measurement uncertainties of 10-7, the average temperature along the beam has to be known within 100 mK since it is a key component in determining the refractive index of air. Temperature measurements at this level are extremely challenging over long distances and especially in an outdoor environment. This paper presents a thermometer for accurate temperature measurements over distances up to a few km. The thermometer is based on direct laser absorption spectroscopy of oxygen near 770 nm. The thermometer yields a spatially continuous measurement of air temperature, and it can provide spatially and temporally well-matching data with an actual distance-measuring laser beam. A field measurement campaign at the 864-m Nummela standard baseline demonstrates applicability of the developed thermometer for improving the refractive index compensation of current high-performance electronic distance meters.",
keywords = "absorption spectroscopy, laser beams, refractive index, temperature measurement, thermometers, air temperature, continuous measurements, electronic distance meters, field measurement, laser absorption spectroscopy, outdoor environment, refractive index of air, relative measurement",
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Spectroscopic thermometry for long-distance surveying. / Tomberg, Teemu; Fordell, Thomas; Jokela, Jorma; Merimaa, Mikko; Hieta, Tuomas.

In: Applied Optics, Vol. 56, No. 2, 10.01.2017, p. 239-246.

Research output: Contribution to journalArticleScientificpeer-review

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AU - Tomberg, Teemu

AU - Fordell, Thomas

AU - Jokela, Jorma

AU - Merimaa, Mikko

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