Applications of GPS in geomatic sciences

Presented in 2nd civil student conference - Tehran University - 1994

Global Positioning system (GPS) and it's application in geodesy, surveying, photogrammetry and other related fields discussed in this paper. Some applied example introduced in each part.

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Solving of GPS carrier phase ambiguity

Presented in 4th civil student conference - Iran University of Science & Technology - 1996 (Best student paper winner)

Carrier phase measurements are affected by the ambiguity term, that is, by an unknown number of complete wavelengths between the satellite and the receiver antenna. The approaches of ambiguity determination discussed in this paper.

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Applications of Green's functions in physical Geodesy

Term paper of advanced physical geodesy course - K.N.Toosi University of technology - 1998

Green's function technique is a method for solving the partial differential equations. This paper is referred to this method with some practical examples.

Strum-Liouville problems, Green's identities and applications of Green's functions in boundary value problems in physical geodesy are some parts of this paper.

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The measurment of terrain tilt with horizontal pendulums

Term paper of advanced geodynamic course - K.N.Toosi University of technology - 1998

One of the variations that occurs on the surface of the earth by tidal phenomena is the terrain tilt. The best instrument for measurement of this quantity is the horizontal pendulum.

This paper is referred to the terrain tilt and measurement with horizontal pendulums. The results of some applied experiments explained at the end part of paper.

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Designing and analysis of a geodetic control network

Presented in K.N.Toosi University of technology as a seminar - 1999

Designing and pre-analysis of geodetic network of Karun 3 dam that has done for applied purposes discussed in this paper.

Sensitivity analysis in Gauss-Markov models and its application in these kind of projects explained at the end part.

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Comparison of terrestrial and GPS observation results in a geodetic control network

Presented in 2nd Symposium on Geodesy for Geotechnical and Structrural Engineeing - Berlin, Germany - May 2002( the Farsi version Presented in Geomatic 79 conference - National Cartographic Center (NCC) of Iran - May 2000)

Precise terrestrial observations in geodetic monitoring network in small areas such as a dam region due to special topographic conditions is common yet. Now , GPS in large networks with distances more then 10km nearly replaced to the terrestrial methods.

This paper is a report of an applied project that had been done for comparison of methods in Karkheh dam's geodetic network. Each method with related analysis and observation scheme executed at the same time.

For comparison of GPS and terrestrial results, it is necessary to transform the GPS coordinate system (WGS84) to local system. By using the Interpolation method the GPS coordinates transformed to local coordinates. Suitable distribution of common points and wide of area ( should be less than 15km2) are important factors in this transformation method.

All of the network's points observed with two methods at the same time, so with selecting the common points in different locations the results of transformation compared.

The common distances (from 278m to 2976m) had 0.1mm to 5.3mm differences between EDM and GPS baseline results. Relative difference was about 1ppm in distances longer than 1000m. But in shorter distances the relative difference increased with decreasing the distance. As the accuracy of EDM instrument was 0.3mm over short distances; this experience shows that GPS can uses for precise measurement of short distances.

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