|Galileo Update, News Archives
Europe has inaugurated its newest Galileo GNSS service center. Located in Torrejón de Ardoz, Spain, the Loyola de Palacio GNSS Service Center will be dedicated to providing constellation information to companies that want to use satellite-sourced data for products and services in sectors such as agriculture, transport and mapping.
The center will serve as an interface between the Galileo navigation system and user communities of the open and commercial services. Additionally, developers of applications that use Galileo’s satellite data will be offered support through consultancy, certification services and quality stamps for their final products. www.satellitetoday.com/
The satellite, assembled by OHB System AG, is now headed for Noordwijk in the Netherlands, where it will undergo an environmental testing campaign and further system testing at the ESTEC’s Test Center on the premises of the European Space Agency (ESA). Before the satellite was shipped, it had successfully completed integration and system testing, according to OHB System. Its twin FOC satellite is in the final phase of completion at OHB System. Over the next few weeks, it will also be integrated and tested, after which it will be shipped to Noordwijk. The two satellites are to be placed in orbit on board a Soyuz launcher, which will is planned to lift off from Kourou in French Guyana this fall. www.gpsworld.com/
To ensure the early interoperability of Europe’s satellite navigation with GPS, the four Galileo satellites have begun broadcasting the ‘offset’ between the parallel navigation systems’ timings, accurate to a few billionths of a second. With satellite navigation based around the highly accurate measurement of signal times, both Galileo and GPS have their own internal reference time systems used to synchronise all system clocks and signals.
The problem is that these time systems are not quite identical, with Galileo System Time being around 50 nanoseconds or less apart from GPS time.
A nanosecond is only a billionth of a second, corresponding to the time light takes to travel 30cm, explained Jörg Hahn, Galileo System Engineering Manager. But this soon adds up, and anyone attempting to use the two systems together might find this ‘offset’ accounting for up to 15m of error, causing an unacceptable contribution to user performance.
Instead, this time offset needs to be known or estimated by the receiver itself. The dissemination of the GPS to Galileo offset can help in constrained environments such as city centres, where only a few satellites are visible in the sky, added Hahn. http://www. hydro-international.com/