{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T14:10:11Z","timestamp":1782483011632,"version":"3.54.5"},"reference-count":44,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2017,8,9]],"date-time":"2017-08-09T00:00:00Z","timestamp":1502236800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>For accurate astronomic and geodetic observations based on radio telescopes, the elevation-dependent deformation of the radio telescopes\u2019 main reflectors should be known. Terrestrial laser scanning has been used for determining the corresponding changes of focal lengths and areal reflector deformations at several occasions before. New in this publication is the situation in which we minimize systematic measurement errors by an improved measurement and data-processing concept: Sampling the main reflector in both faces of the laser scanner and calibrating the laser scanner in situ in a bundle adjustment. This concept is applied to the Onsala Space Observatory 20-m radio telescope: The focal length of the main reflector decreases by 9.6 mm from 85     \u2218     to 5     \u2218     elevation angle. Further local deformations of the main reflector are not detected.<\/jats:p>","DOI":"10.3390\/s17081833","type":"journal-article","created":{"date-parts":[[2017,8,10]],"date-time":"2017-08-10T02:33:58Z","timestamp":1502332438000},"page":"1833","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Terrestrial Laser Scanner Two-Face Measurements for Analyzing the Elevation-Dependent Deformation of the Onsala Space Observatory 20-m Radio Telescope\u2019s Main Reflector in a Bundle Adjustment"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7966-4322","authenticated-orcid":false,"given":"Christoph","family":"Holst","sequence":"first","affiliation":[{"name":"Institute of Geodesy and Geoinformation, University of Bonn, Bonn D-53115, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Schunck","sequence":"additional","affiliation":[{"name":"Institute of Geodesy and Geoinformation, University of Bonn, Bonn D-53115, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Axel","family":"Nothnagel","sequence":"additional","affiliation":[{"name":"Institute of Geodesy and Geoinformation, University of Bonn, Bonn D-53115, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R\u00fcdiger","family":"Haas","sequence":"additional","affiliation":[{"name":"Onsala Space Observatory, Chalmers University of Technology, Onsala SE-43992, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lars","family":"Wennerb\u00e4ck","sequence":"additional","affiliation":[{"name":"Onsala Space Observatory, Chalmers University of Technology, Onsala SE-43992, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Henrik","family":"Olofsson","sequence":"additional","affiliation":[{"name":"Onsala Space Observatory, Chalmers University of Technology, Onsala SE-43992, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roger","family":"Hammargren","sequence":"additional","affiliation":[{"name":"Onsala Space Observatory, Chalmers University of Technology, Onsala SE-43992, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Heiner","family":"Kuhlmann","sequence":"additional","affiliation":[{"name":"Institute of Geodesy and Geoinformation, University of Bonn, Bonn D-53115, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2017,8,9]]},"reference":[{"key":"ref_1","unstructured":"Ioannidis, C., Valani, A., Georgopoulos, A., and Tsiligiris, E. (2006, January 22\u201324). 3D model generation for deformation analysis using laser scanning data of a cooling tower. Proceedings of the 3rd IAG\/12th FIG Symposium, Baden, Germany."},{"key":"ref_2","first-page":"167","article-title":"Deformation analysis of a bored tunnel by means of terrestrial laser scanning","volume":"36","author":"Lindenbergh","year":"2006","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_3","unstructured":"Eling, D. (2009). Terrestrisches Laserscanning f\u00fcr die Bauwerks\u00fcberwachung. [Ph.D. Thesis, Wissenschaftliche Arbeiten der Fachrichtung Geod\u00e4sie und Geoinformatik der Leibniz Universit\u00e4t Hannover]."},{"key":"ref_4","unstructured":"Wang, J. (2013). Towards Deformation Monitoring with Terrestrial Laser Scanning Based on External Calibration and Feature Matching Methods. [Ph.D. Thesis, Wissenschaftliche Arbeiten der Fachrichtung Geod\u00e4sie und Geoinformatik der Leibniz Universit\u00e4t Hannover]."},{"key":"ref_5","first-page":"1","article-title":"The Geodetic Monitoring of the Engineering Structure\u2014A Practical Solution of the Problem in 3D Space","volume":"102","author":"Janowski","year":"2016","journal-title":"Rep. Geod. Geoinform."},{"key":"ref_6","first-page":"147","article-title":"Calibration of Terrestrial Laser Scanners","volume":"123","author":"Holst","year":"2016","journal-title":"Allgem. Verm. Nachr."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1016\/j.isprsjprs.2010.12.001","article-title":"Parameter de-correlation and model-identification in hybrid-style terrestrial laser scanner self-calibration","volume":"66","author":"Lichti","year":"2011","journal-title":"ISPRS J. Photogramm."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.isprsjprs.2009.09.002","article-title":"Terrestrial laser scanner self-calibration: Correlation sources and their mitigation","volume":"65","author":"Lichti","year":"2010","journal-title":"ISPRS J. Photogramm."},{"key":"ref_9","first-page":"295","article-title":"Aiming at self-calibration of terrestrial laser scanners using only one single object and one single scan","volume":"8","author":"Holst","year":"2014","journal-title":"J. Appl. Geod."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/j.measurement.2016.12.053","article-title":"Improvements to the accuracy of prototype ship models measurement method using terrestrial laser scanner","volume":"100","author":"Abbas","year":"2017","journal-title":"Measurement"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1016\/j.precisioneng.2014.11.002","article-title":"Volumetric performance evaluation of a laser scanner based on geometric error model","volume":"40","author":"Muralikrishnan","year":"2015","journal-title":"Precis. Eng."},{"key":"ref_12","unstructured":"Muralikrishnan, B., Shilling, K.M., Sawyer, D.S., Rachakonda, P.K., Lee, V.D., Phillips, S.D., Cheok, G.S., and Saidi, K.S. (2014, January 9\u201314). Laser scanner two-face errors on spherical targets. Proceedings of the Annual Meeting of the ASPE 2014, Boston, MA, USA."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Medi\u0107, T., Holst, C., and Kuhlmann, H. (2017). Towards system calibration of panoramic laser scanners from a single station. Sensors, 17.","DOI":"10.3390\/s17051145"},{"key":"ref_14","first-page":"239","article-title":"Formbestimmung bei Radioteleskopen mittels Terrestrischem Laserscanning","volume":"6","author":"Dutescu","year":"2009","journal-title":"Allgem. Verm. Nachr."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1061\/(ASCE)SU.1943-5428.0000008","article-title":"Laser scanner and terrestrial surveying applied to gravitational deformation monitoring of large VLBI telescopes\u2019 primary reflector","volume":"135","author":"Sarti","year":"2009","journal-title":"J. Surv. Eng."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1115","DOI":"10.1007\/s00190-009-0331-4","article-title":"Gravity-dependent signal path variation in a large VLBI telescope modelled with a combination of surveying methods","volume":"83","author":"Sarti","year":"2009","journal-title":"J. Geod."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1061\/(ASCE)SU.1943-5428.0000082","article-title":"Estimation of focal length variations of a 100-m radio telescope\u2019s main reflector by laser scanner measurements","volume":"138","author":"Holst","year":"2012","journal-title":"J. Surv. Eng."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1515\/jag-2014-0018","article-title":"Improved area-based deformation analysis of a radio telescope\u2019s main reflector based on terrestrial laser scanning","volume":"9","author":"Holst","year":"2015","journal-title":"J. Appl. Geod."},{"key":"ref_19","first-page":"17","article-title":"Challenges and Present Fields of Action at Laser Scanner Based Deformation Analyses","volume":"10","author":"Holst","year":"2016","journal-title":"J. Appl. Geod."},{"key":"ref_20","unstructured":"Johansson, L.E., Olofsson, A., and Beck, E.D. (2016). OSO 20 m Telescope Handbook, Onsala Space Observatory. Technical Report."},{"key":"ref_21","unstructured":"Clark, T.A., and Thomsen, P. (1988). Deformations in VLBI Antennas, Technical Report; Nasa Technical Memorandum 100696."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s00190-010-0410-6","article-title":"Height bias and scale effect induced by antenna gravitational deformations in geodetic VLBI analysis","volume":"85","author":"Sarti","year":"2011","journal-title":"J. Geod."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1016\/j.isprsjprs.2011.01.005","article-title":"Scanning geometry: Influencing factor on the quality of terrestrial laser scanning points","volume":"66","author":"Soudarissanane","year":"2011","journal-title":"ISPRS J. Photogramm."},{"key":"ref_24","unstructured":"Z\u00e1me\u010dnikov\u00e1, M., and Neuner, H. (2017). Untersuchung des gemeinsamen Einflusses des Auftreffwinkels und der Oberfl\u00e4chenrauheit auf die reflektorlose Distanzmesssung beim Scanning. Ingenieurvermessung 17: Beitr\u00e4ge zum 18. Internationalen Ingenieurvermessungskurs, Wichmann."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1016\/j.isprsjprs.2016.12.006","article-title":"An intensity-based stochastic model for terrestrial laser scanners","volume":"125","author":"Wujanz","year":"2017","journal-title":"ISPRS J. Photogram."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1016\/j.isprsjprs.2006.10.004","article-title":"Error modelling, calibration and analysis of an AM-CW terrestrial laser scanner system","volume":"61","author":"Lichti","year":"2007","journal-title":"ISPRS J. Photogramm."},{"key":"ref_27","first-page":"121","article-title":"Point-based versus plane-based self-calibration of static terrestrial laser scanners","volume":"38","author":"Chow","year":"2011","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"7224","DOI":"10.3390\/s130607224","article-title":"Improvements to and comparison of static terrestrial lidar self-calibration methods","volume":"13","author":"Chow","year":"2013","journal-title":"Sensors"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1061\/(ASCE)0733-9453(2005)131:4(135)","article-title":"Error models and propagation in directly georeferenced terrestrial laser scanner networks","volume":"131","author":"Lichti","year":"2005","journal-title":"J. Surv. Eng."},{"key":"ref_30","first-page":"171","article-title":"The impact of angle parameterisation on terrestrial laser scanner self-calibration","volume":"38","author":"Lichti","year":"2009","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_31","first-page":"1","article-title":"From laser point cloud to surface: data reduction procedure test","volume":"9","author":"Zainuddin","year":"2009","journal-title":"Geoinform. Sci. J."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"735","DOI":"10.1007\/s001700170119","article-title":"Data reduction methods for reverse engineering","volume":"17","author":"Lee","year":"2001","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1007\/s001700170075","article-title":"Point data reduction using 3D grids","volume":"18","author":"Lee","year":"2001","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_34","first-page":"169","article-title":"Biased and unbiased estimates based on laser scans of surfaces with unknown deformations","volume":"8","author":"Holst","year":"2014","journal-title":"J. Appl. Geod."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Roscher, R. (2013). Sequential Learning Using Incremental Import Vector Machines for Semantic Segmentation. [Ph.D. Thesis, German Geodetic Commission (DGK)].","DOI":"10.1016\/j.imavis.2012.08.008"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1016\/j.robot.2011.02.011","article-title":"Plant detection and mapping for agricultural robots using a 3D lidar sensor","volume":"5","author":"Weiss","year":"2011","journal-title":"Robot. Auton. Syst."},{"key":"ref_37","unstructured":"Leica Geosystems (2017, August 08). Leica ScanStation P20, Industry\u2019s Best Performing Ultra-High Speed Scanner. Available online: www.leica-geosystems.de."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Jurek, T., Kuhlmann, H., and Holst, C. (2017). Impact of spatial correlations on the surface estimation based on terrestrial laser scanning. J. Appl. Geod.","DOI":"10.1515\/jag-2017-0006"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1515\/jag-2016-0026","article-title":"A synthetic covariance matrix for monitoring by terrestrial laser scanning","volume":"11","author":"Kauker","year":"2017","journal-title":"J. Appl. Geod."},{"key":"ref_40","unstructured":"Mikhail, E., and Ackermann, F. (1976). Observations and Least Squares, Dun-Donelly."},{"key":"ref_41","unstructured":"Wolf, H. (1975). Ausgleichungsrechnung. Formeln zur Praktischen Anwendung, D\u00fcmmler."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"751","DOI":"10.1007\/s00190-010-0408-0","article-title":"Generalization of total least-squares on example of unweighted and weighted 2D similarity transformation","volume":"84","author":"Neitzel","year":"2010","journal-title":"J. Geod."},{"key":"ref_43","unstructured":"Nothnagel, A., Holst, C., Schunck, D., Haas, R., Wennerb\u00e4ck, L., Olofsson, H., and Hammargren, R. (2017, January 15\u201319). Paraboloid deformation investigations of the Onsala 20 m radio telescope with terrestrial laser scanning. Proceedings of the 23rd Meeting of the European VLBI Group for Geodesy and Astronomy, Gothenburg, Sweden."},{"key":"ref_44","unstructured":"Heunecke, O., Kuhlmann, H., Welsch, W., Eichhorn, A., and Neuner, H. (2013). Hanbuch Ingenieurgeod\u00e4sie. Auswertung Geod\u00e4tischer \u00dcberwachungsmessungen, Wichmann. [2nd ed.]."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/8\/1833\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:41:54Z","timestamp":1760208114000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/8\/1833"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,8,9]]},"references-count":44,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2017,8]]}},"alternative-id":["s17081833"],"URL":"https:\/\/doi.org\/10.3390\/s17081833","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,8,9]]}}}