Simulation of Improvement of Orbit Prediction for Optical Communication Satellite Downlink Experiment - Evaluation of accuracy of Two Line Elements

摘要

In order to achieve initial acquisition of laser communication satellites using TLE data, a program was written that performs a conversion between Two Line Elements (TLE) and Consolidated Laser Ranging Prediction Format (CPF). The ultimate goal of the program is to contribute to improved real-time orbit determination utilizing a sequential filter. The accuracy of the program depends on the quality of the TLE, the TLE update frequency and the accuracy of the SGP4 propagator [1] that is used. The results of the program have been checked against some original CPF files and an RMS of differences of less than 1 km was achieved for orbits in between approximately 685-820 km altitude. Due to the increased atmospheric effect at lower altitudes, larger inaccuracies resu For Tandem X (mean orbital altitude of 510 km) the RMS of differences was about 2 km for a period where TLE data was regularly refreshed. Because both the accuracy and update frequency of TLE data are not necessarily consistent over time, the accuracy analysis performed in this text is rather a snapshot of accuracies corresponding to the epochs considered.