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Abstract

The next generation of Galileo is planned to be supported with inter-satellite links (ISL) which can improve the precise orbit determination, communication, and data-exchange capabilities. This research aims to evaluate the exploitation of ISL in the orbit determination of Galileo satellites in simulation-based processing considering the range biases. The inclusion of range biases in the simulated ISL measurements allows for the evaluation of their most promising estimation strategy. Additionally, this research gives an overview of feasible on-ground calibration of the ISL hardware requirements. The performance of the estimation process includes relative weighting coefficients for GNSS and ISL measurements obtained with variance component estimation (VCE). The assessment is performed with stations distributed globally and regionally to vary the number of GNSS observations taking part in the estimation together with different ISL connection schemes. RMS values of estimated ISL range biases depend on the applied ISL connectivity scheme. The accuracy of the bias estimation may be associated with the weighting approach and the number of ground stations. The results indicate that using different VCE approaches might lower orbit errors by up to 20%. The results of this study show how introducing VCE with various simulation parameters into the processing chain might change the accuracy of the orbit determination when ISL range biases are estimated.