Optimalni modeli izravnave meritev z gravimetrom Scintrex CG-3M z upoštevanjem najpomembnejših instrumentalnih vplivov : doktorska disertacija

Repanić, Marija (author), Kuhar, Miran (mentor), Pavlovčič Prešeren, Polona (comentor)

V doktorski nalogi obravnavamo določitev optimalnega modela izravnave gravimetričnih meritev z instrumenti Scintrex CG-3M ob upoštevanju najpomembnejših instrumentalnih vplivov. S pomočjo dostopne literature in izkušenj ob uporabi dveh gravimetrov Scintrex CG-3M smo med najpomembnejše instrumentalne vplive uvrstili histerezo in hod, ki nastaneta zaradi transporta instrumenta, ter pogreške kalibracijske funkcije. Z analizo empiričnih podatkov smo tekom predhodne obdelave ugotovili, da sta oba gravimetra CG-3M obremenjena značilnim vplivom histereze. Za odstranitev vpliva smo za gravimetrične odčitke zadostnega trajanja predstavili algoritem modeliranja histereze z eksponentno funkcijo. Pokazali smo, da je odziv transportnega hoda gravimetra v različnih izmerah specifičen, a za posamezen instrument značilen. Nadalje smo obravnavali zanesljivost določitve kalibracijskih koeficientov in njihove spremembe v odvisnosti od časa, kar lahko značilno vpliva na relativne gravimetrične meritve. Opredelili smo definicijo datuma in določili mere ocene kakovosti gravimetričnih meritev. Na različnih skupinah empiričnih podatkov smo preverili modele izravnave po metodi najmanjših kvadratov, ki so v funkcionalnem in stohastičnem modelu vključevali različne pristope obravnavanja najpomembnejših instrumentalnih vplivov. Pokazali smo, da bi popravke linearnih kalibracijskih koeficientov in koeficientov polinoma druge stopnje za hod bilo potrebno vključiti v funkcionalni model izravnave kot dodatne neznanke. Ob tem lahko histereza značilno vpliva na natančnost Scintrex-gravimetričnih meritev, vendar tega s stohastičnim modelom ne moremo rešiti.

• Language: English
• Keywords: relativna gravimetrija, Scintrex, CG-3M, izravnava po metodi najmanjših kvadratov, model izravnave, instrumentalni vplivi, elastična histereza, transportni hod, kalibracijska funkcija
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publisher: [M. Repanić]
• Year: 2019
• PID: 20.500.12556/RUL-109573
• UDC: 004.652:528.27:528.56(043.3)
• COBISS.SI-ID: 8874081
• Publication date in RUL: 06.09.2019

REPANIĆ, Marija, 2019, Optimalni modeli izravnave meritev z gravimetrom Scintrex CG-3M z upoštevanjem najpomembnejših instrumentalnih vplivov : doktorska disertacija [online]. Doctoral dissertation. M. Repanić. [Accessed 26 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=109573

Secondary language

• Language: Slovenian
• Title: Optimal adjustment models of Scintrex CG-3M gravimeter measurements with respect to the most significant instrumental influences : doctoral thesis

Abstract

The thesis deals with the identification of the optimal adjustment models of Scitnrex CG-3M gravimeter’s measurements with respect to the most significant instrumental error influences. On the basis of available literature and experience with two CG-3M gravimeters, the hysteresis after transport, transport drift and errors in the calibration function are identified as the most significant instrumental error influences in Scintrex CG-3M measurements. The analysis of the empirical data (comprising four sets of different purposes) in the phase of pre-processing showed that the two CG-3M gravimeters are affected with the significant hysteresis effect. An iterative algorithm has been developed, which models hysteresis using exponential function and facilitate its elimination from observation series of sufficient duration. In addition, the analysis showed that the gravimeters exhibit different, but rather regular, drift behaviour during different types of the survey. Furthermore, an uncertainty of determined calibration coefficients or its time change can significantly affect the relative gravity measurements. The problems of datum definition and measures of quality for gravity networks are analysed and resolved. Different adjustment models with respect to the treatment of the most significant error influences in the functional and stochastic part of the adjustment model have been tested on the empirical data. The investigation showed that the corrections of the linear calibration coefficients and coefficients of the second order drift polynomial should be, in general, included in the functional model as parameters. In addition, the hysteresis can significantly affect the precision of the Scintrex measurements, which cannot be remedied by a stochastic model.

• Keywords: relative gravimetry, Scintrex, CG-3M, least squares adjustment, adjustment model, instrumental error influences, elastic hysteresis, transport drift, calibration function