Inside GNSS Media & Research

SEP-OCT 2018

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Page 46 of 67 S E P T E M B E R / O C T O B E R 2 0 1 8 Inside GNSS 47 Mission Segment, and higher uplink rate of the navigation message (lower Age of Data). The gaps in the plots of Figure 4 and Figure 5 in September 2016 are related to system testing activities as per NAGU 2016040. e small bump around May 2017 was caused by a ground seg- ment hardware failure as reported in Service Notice SNGU 2017001, Naviga- tion message not refreshed, published by the European GNSS Service Cen- tre on May 17, 2017. The failed equip- ment was promptly replaced, and with the current redundancy of the Galileo Control Centers, this type of anomaly is no longer expected. A large SISE deviation is observed for GSAT0203 (E26) in June 2017. is was caused by an anomaly that occurred shortly aer a planned clock maintenance activity. e Signal In Space was not flagged in a timely fashion as unhealthy to protect the users. e onset of anomalies and isolated large SISE errors is expected to gradually decrease over time as new ground segment upgrades and opera- tional improvements are deployed, con- tributing to the overall system reliability towards the full services phase in 2020. The overall Galileo SISE perfor- mance, in terms of 95% statistics, is already at least a factor of two better than other GNSS (O. Montenbruck et alia). is is mainly driven by the on- board clock stability in combination with the high uplink rate of the Galileo navigation messages. As shown in Figure 6 , the cumulative Age of Data (AoD) for FIGURE 5 Constellation SISE 95% (FNAV), 30 days moving average (1 day time step), September 1, 2014 – May 31, 2018 10 9 8 7 6 5 4 3 2 1 08-14 02-15 08-14 08-15 02-16 08-16 02-17 11-17 11-14 05-15 08-14 11-15 05-16 11-16 08-17 05-18 SISE 95% (FNAV DF) [m] See all configurations and schedule a demo at PCIe-Based System Create complex simulation scenarios that integrate multiple constellations, multiple frequencies, dynamic interferences and much more. SDX combines GPU-accelerated computing and COTS hardware into a truly flexible and complete simulator, available in a wide range of configurations and deployment options to meet any simulation need. NEW CDM-5 Clock Distribution Module Distributed 1PPS and 10MHz Signals in PCIe format NAVWAR: Talen-X BroadSim and BroadSim Anechoic

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