Microwave Engineering Europe - May 2008 - (Page 24)

24 GPS & SateLLite GPS developments: Galileo moves forward with successful Giove-B satellite launch — Broadcom targets AGPS in mobile phones and devices Edited by Jean-Pierre Joosting, he Giove-B (Galileo In-Orbit Validation Element) demonstrator and second test satellite for Europe’s fledgling satellite navigation project, Galileo, has been successfully launched and deployed from the Baikonaur Cosmodrome in Kazakhstan. The satellite was placed into a medium altitude orbit around the earth by a Soyuz/Fregat rocket operated by Starsem. Developed and manufactured by Astrium, the 500 kg satellite carries Galileo’s key technologies into space for the first time, and is a seen as a key test for the overall system. Two years after the Giove-A mission, this latest satellite will continue the demonstration of critical technologies for the navigation payload of future operational Galileo satellites. One of these technologies is a Passive Hydrogen Maser (PHM) atomic clock, which today is the most precise time piece to orbit the Earth. It will be accurate to 1-ns or one billionth of a second per day. The PHM can guarantee stability performances within the Galileo requirements for more than eight hours without any correction/ upload from ground. However, like its predecessor, Giove-B also carries two redundant or back-up small-size rubidium atomic clocks, each with a stability of 10-ns per day. In the future, two PHMs will be used as primary clocks onboard operational Galileo satellites, with two rubidium clocks serving as back-up. Giove-B also incorporates a radiationmonitoring payload to characterise the space environment at the altitude of the Galileo constellation, as well as a laser retroreflector for high-accuracy laser ranging. Signal generation units will provide representative Galileo signals on three separate frequencies broadcast via an L-band phase array antenna designed to entirely cover the visible earth below the satellite. The next step in the Galileo programme will be the launch of four operational satellites, to validate the basic Galileo T Photograph courtesy of ESA:— Giove‑B in orbit (artist’s impression). space and related ground segment, by 2010. Once that In-Orbit Validation (IOV) phase is completed, the remaining satellites will be launched and deployed to reach the Full Operational Capability (FOC), a constellation of 30 identical satellites. Separately, on the funding front, the European Union ratified on April 23rd the Euros 3.4 billion public bailout of the project. The approval removes the final hurdle after EU governments decided in November to use taxpayers’ money to rescue the project, which is over budget and behind schedule. Leading up to the launch Before the launch, Giove-B underwent final tests at the European Space Research and Technology Centre ESTEC of the European Space Agency ESA in Noordwijk, the Netherlands. The first test platform, Giove-A, produced by Surrey Satellite Technology Limited (Guildford, England), has worked flawlessly in orbit. As prime contractor for Giove-B, Astrium was responsible for developing, manufacturing and delivering the satellite, its payload and the ground control segment. The German Astrium site in Ottobrunn supplied the avionic subsystem with central on-board computer, and the assembly of the photovoltaic cells within the solar generator. Astrium UK designed and manufactured the payload, which included integrating and testing the Space Passive Hydrogen Maser (S-PHM) clock within it. The Portsmouthbased team was also responsible for the development, installation and test of the Ground Satellite Control system at the operations centre in Fucino, Italy, as well as at the IOT (In Orbit Test) station in Redu, Belgium, including the antenna. Astrium in Madrid delivered the structure and the thermal subsystem for the payload, the L-band navigation antenna as well as the payload adapter and separation system used during the launch. The French Astrium team in Les Mureaux provided the panels for the solar generator. Single die CMOS chip brings in-door and urban GPS to mobile phones an devices Broadcom’s BCM4750 is a single-chip GPS receiver which integrates a high-performance baseband section with a low-noise CMOS radio front end. It is designed to interface with Microwave Engineering Europe ● May 2008 ● www.mwee.com http://www.mwee.com

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Microwave Engineering Europe - May 2008 News Contents Comment Cover Feature: How to Succeed as a GaAs Foundry Wireless Networking: Wireless Coverage Where Everybody WINS Wireless Networking: Achieving Good Coexistence in the 2.4 GHz ISM Band GPS and Satellite: GPS developments: Galileo Moves Forward with Successful Giove-B Satellite Launch — Broadcom Targets AGPS in Mobile Phones and Devices Raising the Bar for the Radio: Making 802.11n Work Reducing Power Consumption in Ultrawideband Chips WiMax Catches Second Test Wave Products Calendar

Microwave Engineering Europe - May 2008

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