Dissertations / Theses on the topic 'Geoid determination'
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Li, Yecai. "Airborne gravimetry for geoid determination." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/NQ54797.pdf.
Full textGarcia, Ramon V. "Local geoid determination from GRACE mission /." The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486398195325232.
Full textSerpas, Juan Gilberto. "Local and regional geoid determination from vector airborne gravimetry." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1066757143.
Full textWan, Mohd Akib Wan Abdul Aziz. "A preliminary determination of a gravimetric geoid in Peninsular Malaysia." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283665.
Full textKamarudin, Md Nor. "Local geoid determination from a combination of gravity and GPS data." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363535.
Full textInerbayeva, (Shoganbekova) Daniya. "Determination of a gravimetric geoid model of Kazakhstan using the KTH-method." Thesis, KTH, Geoinformatik och Geodesi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-52284.
Full textNahavandchi, Hossein. "Precise gravimetric-GPS geoid determination with improved topographic corrections applied over Sweden." Doctoral thesis, KTH, Geodesy and Photogrammetry, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2726.
Full textFeatherstone, William Edward. "A G.P.S. controlled gravimetric determination of the geoid of the British Isles." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306204.
Full textAbdalla, Ahmed. "Determination of a gravimetric geoid model of Sudan using the KTH method." Thesis, KTH, Geodesi och satellitpositionering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199670.
Full textZhang, Kefei. "An evaluation of FFT geoid determination techniques and their application to height determination using GPS in Australia." Curtin University of Technology, School of Surveying and Land Information, 1997. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=11047.
Full textPositioning System (GPS) and Australian Height Datum Data that the absolute accuracy of the new geoid is better than 33cm and the relative precision of the new geoid is better than 10~20cm. This new geoid can support Australian GPS heighting to third-order specifications.
Esan, Olugbenga. "Spectral analysis of gravity field data in view of sub-decimeter geoid determination." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0015/MQ55259.pdf.
Full textDaras, IIias. "Determination of a gravimetric geoid model of Greece using the method of KTH." Thesis, KTH, Geodesi och satellitpositionering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199682.
Full textGachari, Moses Karoki. "Determination of a gravimetric geoid for the eastern Africa region : the classical and spectral approaches." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337722.
Full textYang, Hyo Jin. "Geoid Determination based on a Combination of Terrestrial and Airborne Gravity Data in South Korea." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388677708.
Full textÅgren, Jonas. "Regional Geoid Determination Methods for the Era of Satellite Gravimetry : Numerical Investigations Using Synthetic Earth Gravity Models." Doctoral thesis, KTH, Infrastructure, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-55.
Full textIt is the purpose of this thesis to investigate different regional geoid determination methods with respect to their feasibility for use with a future GOCE satellite-only Earth Gravity Model (EGM). This includes investigations of various techniques, which involve different approximations, as well as the expected accuracy. Many, but not all, of these tasks are tested by means of Synthetic Earth Gravity Models (SEGMs). The study is limited to remove-compute-restore methods using Helmert condensation and to Sjöberg's combined approach (method with additive corrections).
First, a number of modifications of Stokes' formula are tested with respect to their compatibility with a GOCE EGM having negligible commission error. It is concluded that the least squares modification method should be preferred.
Next, two new point-mass SEGMs are constructed in such a way that the resulting models have degree variances representative for the full and topographically reduced gravity fields, respectively. These SEGMs are then used to test different methods for modified Stokes' integration and downward continuation. It is concluded that the combined method requires dense observations, obtained from the given surface anomalies by interpolation using a reduction for all known density anomalies, most notably the topography. Examples of other conclusions are that the downward continuation method of Sjöberg (2003a) performs well numerically.
To be able to test topographic corrections, another SEGM is constructed starting from the reduced point-mass model, to which the topography, bathymetry and isostatic compensation are added. This model, which is called the Nordic SEGM, is then applied to test one strict and one more approximate approach to Helmert's condensation. One conclusion here is that Helmert's 1st method with the condensation layer 21 km below sea level should be preferred to Helmert's 2nd condensation strategy.
The thesis ends with a number of investigations of Sjöberg's combined approach to geoid determination, which include tests using the Nordic SEGM. It is concluded that the method works well in practice for a region like Scandinavia. It is finally shown how the combined strategy may preferably be used to estimate height anomalies directly.
Ågren, Jonas. "Regional geoid determination methods for the era of satellite gravimetry : numerical investigations using synthetic earth gravity models /." Stockholm, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-55.
Full textMphuthi, Siphiwe M. Matthews. "A comparison of the least squares collocation and the fast Fourier transform methods for gravimetric geoid determination." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/22854.
Full textHwang, Cheinway. "Orthogonal functions over the oceans and applications to the determination of orbit error, geoid and sea surface topography from satellite altimetry /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487758680161533.
Full textOdera, Patroba Achola. "Precise determination of a local geoid model and a reference height system for the establishment of a modern vertical geodetic datum." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/161036.
Full textKiamehr, Ramin. "Precise Gravimetric Geoid Model for Iran Based on GRACE and SRTM Data and the Least-Squares Modification of Stokes’ Formula : with Some Geodynamic Interpretations." Doctoral thesis, KTH, Transporter och samhällsekonomi (stängd 20110301), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4125.
Full textQC 20100906
Ma, Wei-Ming. "Local geoid determination using the Global Positioning System." Thesis, 1988. http://hdl.handle.net/10945/23288.
Full textShih, Hsuan-Chang, and 施亘昶. "Multiple-altitude airborne gravity surveys and applications to geoid determination and Kuroshio Current." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/23065363156905077284.
Full text國立交通大學
土木工程學系
98
Multiple-altitude airborne gravity data are now available due to the effort of Ministry of the Interior, Taiwan and are distributed at the altitudes of 5000 m and 1500 m, covering the Taiwan Island, Kuroshio Current east of Taiwan, Taiwan Strait and Dongsha Atoll. The computer programs for the data reduction and accuracy analysis of scalar airborne gravimetry have been developed and produced reliable gravity data at the three airborne gravity surveys. Several de-noising tools, including the Gaussian filter, Butterworth filter and EEMD of HHT, were evaluated using a survey line from the Kuroshio Current airborne gravity survey. A filter width between 150 to 180 s is appropriate between noise reduction and gravity signal preservation. The analysis of a survey line from the Kuroshio survey shows the outlier detection and down-weighting technique yields an improvement of 0.69 mgal (compared with upward-continued surface gravity). The accuracy of the gravity anomalies from the three airborne gravity surveys is about 2 to 4 mgal. The spatial resolutions are 6 and 8 km (half-wavelength) at the altitudes of 1500 m and 5000 m, respectively. The airborne gravity anomalies agree well with the upward-continued surface gravity anomalies, except over high mountainous areas and locations with sparse surface gravity. For one cm-level geoid model a band-limited LSC, combining airborne and surface gravity data, in the RCR procedure was used. Evaluation of EGM08 using GPS/leveling-derived geoid undulations and surface gravity anomalies around Taiwan shows the improvements both on the gravity anomaly and height anomaly. The grid of TWDTM2008 was assessed by the leveling-derived heights at the benchmarks and shows a standard deviation of 5.25 m. The geoid model, Model 7, show yields standard deviations of 2.2, 6.6, 7.6 and 4.8 cm along the north, east, central and south first-order GPS/leveling routes, respectively. A crossover method for computing zonal and meridional ocean current components was developed. The error analysis concludes that a DOT at mm-level accuracy is needed to obtain ocean current velocities at the 10 cm•s-1 accuracy and 6 km resolution. To achieve a 10 cm•s-1 accuracy, the DOT must be filtered to a 100 km spatial resolution or coarser. Ocean currents at the T/P and JASON-1 crossover A and B were in-situ compared with the model-derived velocities and show a good agreement.
Tseng, Jung-Ho, and 鄭榮和. "Orthometric Height Determination by GPS Ellipsoidal Heights and a prior Information of Local Geoid." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/89196148514682628033.
Full text國立成功大學
測量工程學系
89
The datum inconsistency must be taken into consideration for the orthometric height determination by integration of GPS heights,spirit heights and the geoidal undulation ,because those heights refer to different reference surfaces. In the study, a height datum transformation model has been developed,and the least squares collocation has been used for solving the systematic errors caused by a priori undulation model and height networks. It is shown that the transformation model developed in the study can improve the absolute accuracy of orthometric heights compared with models that do not consider the datum inconsistency problem and the systematic errors. The absolute accuracy of transformed orthometric heights is about 2-3 cm both for the local and for linear leveling height transformation with a global undulation model EGM96 or a local undulation model. But the relative accuracy of all transformation models tested in the study is similar.
Liu, Hui-Ching, and 劉蕙菁. "A Study on the Determination of the Best Taiwan Geoid Model Using Gravity Method." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/86247730879748389367.
Full text國立交通大學
土木工程系
91
Due to the rapid development of GPS technique these years, it has been extensively applied to physical geodesy. GPS technique can obtain high-accuracy ellipsoidal heights, and change the face and concept of traditional heighting procedure. However, leveling height is orthometric and GPS height is ellipsoidal, so geoid undulation is essential for relating the two. If we can build up a high-accuracy geoid model, then GPS will be an inexpensive method to measure orthometric. The geoid model has been strictly computed for Taiwan area in this research using Stokes’ formula with two-dimensional plane fast fourier transform (2D Plane FFT), one-dimensional spherical fast fourier transform (1D Spherical FFT) techniques and least square collocation (LSC) methods by remove-compute-restore technique. The computations of geoid undulations were carried out using data from EGM96 spherical harmonic model and residual terrain model for Taiwan. We use some gravity anomaly data, which are measured in different time, different distribution and different density, to compute the best Taiwan geoid model, and checked the accuracy of these models by GPS/Leveling observations. The numerical analysis results show that the result using gravity anomaly collected by Academia Sinica (Yen et al., 1990) is better than other three items. The root mean square of the difference between the geoid undulations computed by gravimetric and GPS/Leveling methods is about 5 cm. According to the results, Stokes’ formula with 1D Spherical FFT is better then 2D Plane FFT method, and LSC is the best one. Moreover, the best Taiwan geoid computed by gravimetric is about 12.993 m to 28.564 m. The maximum, minimum, standard deviation, and root mean square of the difference between the geoid undulations computed by gravimetric and GPS/Leveling methods are 5.8, -9.5, 2.56 and 4.78 cm.
Chen, Wei-Yao, and 陳緯耀. "A Study of Determination of Taiwan’s Local Geoid by Combination of GPS, Leveling amd Gravity Data with Point Masses." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/08958507492680862301.
Full text國立成功大學
測量及空間資訊學系碩博士班
94
Abstract In this study, a combination of GPS, leveling, local gravity data and the global gravity model EGM96 with the point mass model is presented for the local geoid determination in Taiwan’s area. The observations include 1719 ellipsoidal height data from GPS measurement and leveling height data at benchmanks of first order in Taiwan as well as a set of free-air gravity anomaly data. Since the point mass model has a close relation with the local mass distribution, the global parameters used in the point mass model may be not suitable for local use. Hence, the parameters in the point mass model, namely the size of grids, the depth of mass points and sampling range are investigated in detail. Our experiments show that the entire accuracy at a 9 cm level is achievable, and the accuracy in the mountain’s area is about 13 cm.