Document Type : Research Paper

Author

• Khosrou Khajeh (Translator)

Abstract

The widespread use of GPS has been accompanied with great deal of success and has already evolved into a true 3D instrument. Therefore, the major attempt to complete a GPS project is often focused on elevation issues. This paper examines the GPS elevation-determination limits, including GPS measurements, geoid issues and datum. Next, the GPS elevation-determination is described with a look at three applications of deformation control, GPS mapping with instantaneous processing, and device control and guidance.
In practice, GPS elevation-determination usually involves three aspects:
1 - Oval height measurement with GPS
2 - Applying the geoid model
3 - Adjustment of the orthometric (or normal) height so that the altitude base is appropriate.
All of these issues create limitations, and the importance of each one, depending on the breadth and magnitude of the GPS mapping, is different, so here some of these limitations are studied in greater details.