sts leap second information in the navigation message, al- lowing receivers to determine UTC. BeiDou also broadcasts offsets between BDT and time from GPS, Galileo, and GLONASS. Galileo The European Union, developer of Galileo via the European GNSS Supervisory Agency (GSA), started launching experimental satellites in 2005, followed by operational satellites in 2011. In December 2016, the GSA declared initial operating capability, but the system has not yet reached full operational status. Galileo, like some other systems, also has a strong search and rescue (SAR) capability on board (to receive signals from emergency distress beacons). Galileo is designed to offer global coverage using up to 24 MEO satellites in 3 different orbital planes with up to 6 spares. As of this writing, there are 22 active operational satellites in the system with 4 more planned to launch in 2020-2021 and 8 more after 2022. As with other systems, there is a significant ground-based control and monitoring segment. Galileo system time (GST) is a continuous timescale (no leap seconds) maintained by the Galileo Control Segment and synchronized to UTC(k) with a nominal offset below 50 ns. The GST epoch started at 00:00:00 UTC on Sunday, 22 August 1999. Galileo also broadcasts a signal indicating the difference between GST and UTC as well as the dif- ference between GPS time and GST-a parameter known as the GPS-Galileo time offset (GGTO). This GGTO has a performance goal to be less than 20 ns for 95% of the time. It also broadcasts leap second information in the navigation message, allowing receivers to determine UTC. The goal is for the recovered time offset from UTC to be less than 30 ns for 95% of the time. At the time of writing, the current performance is that the 95th percentile of the daily average of the dis- seminated UTC accuracy is less than 15 ns. Like other systems, most Galileo receivers also support combined GPS+Galileo dual constellation mode for enhanced operation. IRNSS In 2013, the Indian government started launching the In