The last two European Galileo satellites have joined the operational constellation, transmitting navigation signals to 3 billion users around the globe and relaying distress calls to rescuers. Its entry into service follows a summer test campaign and will result in a measurable increase in positioning accuracy and better data delivery performance of the Galileo system overall. The Galileo 27 and 28 satellites were launched late last year and underwent their in-orbit test review at the end of April, conducted between ESA, satellite maker OHB and navigation payload maker Surrey Satellite Technology ( SSTL). Its key findings included the fact that the payloads of both satellites are performing extremely well, among the best in the entire constellation, and that both satellites entering service increase position accuracy and system robustness. A successful system/operations in-orbit test review followed, co-chaired by ESA and EUSPA, the EU Space Program Agency, in overall charge of commissioning, which confirmed the health of the satellites. Now, following a successful test campaign this summer, these two new Galileo satellites have become the first to transmit an enhanced navigation message, resulting in three key improvements for public users of the Galileo Open Service: – Acquisition of Faster navigation data that allows users to establish a first position more quickly. – Increased robustness in challenging environments, such as urban centers where satellite visibility may be reduced by tall buildings. – Easier access to time information in the navigation message for users who have only a rough estimate of time on the order of a second or two. To test and transmit this new navigation message, Thales Alenia Space in Italy, SSTL, OHB and ESA developed new software for the Navigation Signal Generation Unit and uploaded it to the two satellites. Over the summer, ESA carried out an extensive test campaign to ensure compatibility of the entire Galileo system at unit, payload, satellite, ground and system level with the enhanced message. As part of this effort, EUSPA oversaw receiver testing to ensure that this compatibility was extended to Galileo receivers and chipsets on the market. These latest launched satellites were ideal test cases for improved navigation message and software. Stefan Wallner, Head of the G1 Space Signal Engineering Unit, comments: “This test was crucial for the entire Galileo system, as it means that end users can now receive a first positioning fix twice as fast, up to just 16 seconds. Transmission of the enhanced signals from the Galileo 27 and 28 satellites allowed the team to confirm their correct implementation and characterize their long-term performance. Following a successful Test Review Board, the satellites returned to service on August 29. Bastiaan Willemse, Head of ESA’s Galileo Total Operational Capability Satellite Management Service, said: “Now that the tests have been completed, we come to an exciting time for the entire Galileo family, because this is the point where users can start to benefit from these new Galileo satellites. In addition, the updates will further boost the performance of the Galileo system in general. This new software will not only be uploaded to all Galileo satellites already in orbit starting in October, but will also be integrated into all satellites that have not yet been launched.”