Satellite Orbits Determination Using TLE Data

Today satellite techniques are essential for various application areas. Also state-of-the-art geodesy relies on measurement techniques utilizing artificial earth-satellites. Satellite measurements contribute to the determination of the earth's shape, monitoring the earth’s gravity field and the atmosphere, or to global point positioning at the cm-level. In this context monitoring networks for determining crustal deformations and plate deformations have been established by geodesy. Orbital parameters belonging to satellites have published on the internet in various formats by different observation stations. One of these is the TLE (Two Line Elements) data developed by North American Aerospace Defense Command. TLE data for all the satellites are automatically generated and are offered to users by NORAD. The TLE consist of two or three lines of formatted text. But the parameters in these data sets are the "mean" values. In order to achieve a good estimations, appropriate propagation models - Simplified General Perturbation models- (SGP SGP4, SGP8, SDP4 and SDP8) according to satellite period is required to use. The aim of this article, the satellite's position, velocity and other parameters is to determine how to obtain using TLE data.