Document Type : Research Paper

Author

• Alireza Azmudeh Ardalaan

Abstract

With GPS, the plane coordinates can be determined 10 to 20 times more accurate than traditional (classical) methods. This high level of accuracy can be achieved by one or two hours of observation and without any need for direct view between the stations. Because of this, GPS is becoming the only means of determining flat coordinates. The only disadvantage of GPS is that it cannot directly determine the altitudes. As the number of GPS users has grown, today a great deal of research is conducted around the world to find ways to determine the altitudes with the help of GPS. In this paper, one of the proposed methods is carefully examined, and hints for writing computer program
for this aim will be presented.
In the first part of this paper, we tried to make the necessity of application of 3D GPS in position determination clear. In the second section, existing methods for determining orthometric height are reviewed. Finally, one of these methods and its practical way of application will be explained
in detail.
In this discussion, it is assumed that the reader has basic information about principles and method of using GPS in determining position of geodetic points, and that he/she is also familiar with principles of least squares and with the way of applying them on altitude networks.