User Tools

Site Tools


information_for_astronomers:user_guide:antenna

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
information_for_astronomers:user_guide:antenna [2016/06/28 08:55]
akraus
information_for_astronomers:user_guide:antenna [2022/03/28 12:09] (current)
akraus
Line 15: Line 15:
 Latitude 50°31'​29.4"​ North (50.52483°); ​ Latitude 50°31'​29.4"​ North (50.52483°); ​
 </​code>​ </​code>​
-the Altitude (track level/elevation axis) is 319/369m. These positions are based on  +the Altitude (elevation axis = reference point) is 416.825 m (height over the reference ellipsoid). These positions are based on  
-[[http://​www.ccivs.bkg.bund.de/​EN/​Quarterly/​VTRF-Results/VTRF-Stations/vtrf-stations_node.html|observations]] of the  +[[https://​www.ccivs.bkg.bund.de/​index.php?​uri=quarterly/stationcoordinates/xyz|geodetic VLBI observations]] of the  
-[[http://​ivscc.bkg.bund.de|Internation ​VLBI Service for Geodesy & Astrometry (IVS)]]+[[http://​ivscc.bkg.bund.de|International ​VLBI Service for Geodesy & Astrometry (IVS)]]. The cartesian coordinates 
 +<​code>​ 
 +x = 4033947.225142 m 
 +y = 486990.906449 m 
 +z = 4900431.141999 m (as of May 2019) 
 +</​code>​ 
 +are have been used to determine the geographic coordinates above
 (Reference frame is the Earth ellipsoid defined by [[http://​en.wikipedia.org/​wiki/​World_Geodetic_System|WGS84]]). (Reference frame is the Earth ellipsoid defined by [[http://​en.wikipedia.org/​wiki/​World_Geodetic_System|WGS84]]).
 +Note, that these values correspond to the cross-section of the azimuth and elevation axis (i.e., the height of the
 +elevation axis given above). That's the reference point ("​geodetic point"​) of the antenna.\\
 +The corresponding track level height is 366.8 m.
 +
 +For some purposes, the height with respect to the [[https://​en.wikipedia.org/​wiki/​Geoid|Geoid]] (i.e. "above mean sea level"​) is relevant. There are different models for the Earth gravitational field (which defines the amsl level), e.g., [[https://​en.wikipedia.org/​wiki/​EGM96|EGM96]] or [[http://​earth-info.nga.mil/​GandG/​wgs84/​gravitymod/​egm2008/​egm08_wgs84.html|EGM2008]]. In Germany, also the [[https://​de.wikipedia.org/​wiki/​Deutsches_Haupth%C3%B6hennetz|DHHN2012]] model is in use (sometimes also the older DHHN92). The latter is the basis for most topographic map material of the area. On the other hand, [[https://​en.wikipedia.org/​wiki/​Shuttle_Radar_Topography_Mission|SRTM]] data are with respect to the EGM96 Geoid. ​
 +
 +With these models, the following heights can be derived
 +
 +^Model^Correction w.r.t. WGS84 ellipsoid^Elevation axis height (amsl)^Track level height (amsl)^
 +|EGM96 ​   | -48.0586 | 368.6445 | 318.6445 |
 +|EGM2008 ​ | -47.5935 | 369.1096 | 319.1096 |
 +|DHHN2012 | -47.698 ​ | 369.0051 | 319.0051 |
 +(Based on results with online calculators from [[http://​gibs.bkg.bund.de/​geoid/​gscomp.php?​p=g|BKG]] and [[https://​geographiclib.sourceforge.io/​cgi-bin/​GeoidEval|geographiclib]])
  
 == Axis limits / Cable wrap == == Axis limits / Cable wrap ==
  
 The Effelsberg telescope has an altazimuth-mount,​ with the limits:\\ The Effelsberg telescope has an altazimuth-mount,​ with the limits:\\
-33.5° ≤ Azi ≤ 503° (0° is North)\\+33.5° ≤ Azi ≤ 503° (i.e., 360° + 143° - there is an overleap in the East, 0° is North, 90° East)\\
 8.1° ≤ Elv ≤ 89°\\ 8.1° ≤ Elv ≤ 89°\\
  
information_for_astronomers/user_guide/antenna.1467096932.txt.gz · Last modified: 2016/06/28 08:55 by akraus