Analysis of scaling parameters of the batch unscented transformation in satellite orbit determination using satellite laser ranging data

다국어 초록 (Multilingual Abstract)

The object of the present study is placed on elevating the degree of precision for the orbit determination by settling on the appropriate parameters. The orbit determination algorithm uses the batch unscented transformation method as the estimation method for determining the precise orbits for satellite using the Satellite Laser Ranging (SLR). Hence, the main content of the study is composed of the kinematic model, observation model and estimation algorithm of the batch unscented transformation method. The estimation algorithm had series of processes repeated to determine the appropriate scaling parameter. In the kinematic model, the effects of the Earth's asymmetrical gravitational field, the atmospheric drag, solar radiation and the gravitational perturbations of the Moon and the Sun, were considered and in the observation model, the tropospheric path delay was applied. The observation data used actual TOPEX/POSEIDON Satellite Laser Ranging data and utilizes the Normal Point (NP) data observed from the ground station to gain the azimuth and elevation angle along with the distance of the satellite measured from the ground station observatory. As the research approach to increase the precision for the orbit determination, the dispersion point surrounding the average value was extracted based on the average value and the covariance value when extracting the point of dispersion in the unscented transformations. Moreover, to determine the appropriate scaling parameters, the generally estimated ranges of scaling factor were set-up to compare the orbit residuals of the results with the substitutes of each parameters. To verify the performance, the results of the batch unscented transformation method were compared with those from no error observation data by adopting the various observation data for enabling to generally accept the determined scaling parameter. It was able to settle the range for the system's scaling parameters following the degree of discontinuity of observational data and the appropriate scaling parameters were determined for each observation data to analyze the precision and the tuning properties of the scaling parameters for each observatory. As a result, it was confirmed that the orbit determination of the satellite by using the batch unscented transformation method achieves few tens of cm-levels had been accomplished. Through the results of the present study, it was able to give insights on the roles of scaling parameters for the batch unscented transformation method as well as possible usage of the method with small amounts of observation data.