Availability Analysis of GNSS Orbit and Clock Files

Abstract

Precise point positioning with Global Navigation Satellite Systems (GNSS), orbit and clock products are mandatory. Today, different analysis centers produce satellite orbit and clock products. At the same time, the latency of these products is divided into three different categories. In this study, the satellite availability analysis of the publicly available final, rapid and ultra-rapid orbit (sp3) and clock files were investigated for Global Positioning System (GPS), Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS), European Global Navigation Satellite System (Galileo), BeiDou Navigation Satellite System (Beidou-2, BeiDou-3) and Quasi-Zenith Satellite System (QZSS) satellites within a one-year period of 2021. In addition, clock biases that do not exist in orbit files have also been calculated for each system. The results show that average number of GPS and GLONASS satellites are consistent among the products, however, the average GALILEO and BeiDou satellites are significantly changing among the products. The minimum average number of Galileo satellites was calculated for the final, rapid and ultra-rapid orbit products for the Centre national d'études spatiales (CNES (final)), German Research Centre for Geosciences (GFZ (rapid)) and GFZ (ultra) analysis centers, respectively. The minimum average number of satellites for BeiDou-3 medium earth orbit (MEO) and QZSS was calculated for the CODE analysis center. © 2023, TUBITAK. All rights reserved.