Nummela Standard Baseline

In this article we are going to delve into the topic of Nummela Standard Baseline, which has generated great interest in recent years. _Var1 is a concept that has been the subject of debate and discussion in different areas, from politics to science. Throughout history, Nummela Standard Baseline has played a fundamental role in society, shaping the way people interact with each other and the environment around them. In this sense, it is essential to understand in depth the different aspects that encompass Nummela Standard Baseline, as well as its influence on decision-making and the configuration of the reality that surrounds us. Therefore, throughout this article we will explore the different approaches and perspectives related to Nummela Standard Baseline, with the aim of shedding light on a topic that continues to arouse great interest and curiosity today.

Photograph of one of the pillars of standard baseline in Nummelanharju (municipality of Vihti).

Nummela Standard Baseline is a baseline used to calibrate rangefinders,[1] in Finland, located in the municipality of Vihti, Nummelanharju (esker) where it was built in 1932.[2]

Winding ridge of stratified gravel and sand was chosen as a location for measurements since temperature variations cause very little displacement on soil where benchmarks are located. Measurement devices such as theodolite and mirrors are then placed on those pillars. Careful preliminary measurements such as levelling height differences of observation pillars reference points are required before actual measurements can begin.

In 1947, a white light interference based measurement system was taken to use.[3] It was developed by Yrjö Väisälä. Before that baseline was defined by quartz made measuring rod, which was used to calibrate 24-meter long invar-wire. Standard baselines length is invar-wire multiplied by 36, which is 864 meters.[4]

Measured numerical value for the 2007 standard baseline is 864 122.86 millimetres ±0.002 mm to ±0.007 mm uncertainty.[2] 864 122.86 mm ≈ 864 m. Previously used quartz rod had 0.1 mm deviation from 1 meter – intended length – and it was taken account in new measurements.[2] Because of accuracy, curvature of earth had to take in account when building the baseline: the middlepoint 432 m is 14.6 mm lower than zero & 864 -points. (Fig 17 in ref "144" [2])

References

  1. ^ Jokela, jorma; Häkli, P.; Poutanen, M.; Kallio, U.; Ahola, J. (2012) . "Improving Length and Scale Traceability in Local Geodynamical Measurements". In Kenyon, Steve; Pacino, Maria Christina; Marti, Urs (eds.). Geodesy for Planet Earth. International Association of Geodesy Symposia. Vol. Improving Length and Scale Traceability in Local Geodynamical Measurements. Buenos Aires, Argentina: Springer Berlin Heidelberg. p. 59. doi:10.1007/978-3-642-20338-1_8. ISBN 978-3-642-20338-1.
  2. ^ a b c d Jokela, Jorma; Häkli, Pasi (2010). Interference measurements of the Nummela standard baseline in 2005 and 2007 (PDF). Vol. 144. Publications of the Finnish Geodetic institute. ISBN 978-951-711-283-3. Archived from the original on 12 August 2011. Retrieved 16 June 2016.
  3. ^ Jokela, Jorma; Häkli, Pasi (8–13 October 2006). "Current research and development at the Nummela Standard Baseline. Conference proceedings" (PDF). Shaping the Change, XXIII FIG Congress.
  4. ^ Pollinger, Florian; Meyer, Tobias; Beyer, Jens; R Doloca, Nicolae; Schellin, Wolfgang; Niemeier, Wolfgang; Jokela, Jorma; Häkli, Pasi; Abou-Zeid, Ahmed; Meiners-Hagen, Karl (2012). "The upgraded PTB 600 m baseline: a high-accuracy reference for the calibration and the development of long distance measurement devices}". {Measurement Science and Technology. 23 (9): 094018. Bibcode:2012MeScT..23i4018P. doi:10.1088/0957-0233/23/9/094018. S2CID 120328722. Retrieved 16 June 2016.

60°20′21.72″N 24°18′36.47″E / 60.3393667°N 24.3101306°E / 60.3393667; 24.3101306 (Southern end of the Nummela Standard Baseline.)

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