The new fixed star in orbit
Article from TÜV SÜD Journal 3/2010
 | Since antiquity, people have been casting their eyes to the heavens to find their way on Earth. With the satellite navigation system Galileo, the European response to GPS, a new star is rising in the navigation sky. The simulations and tests are already under way – at the GATE test bed in Berchtesgaden, Germany. |
Cows graze on verdant pastures. Stands of evergreens, fixed firmly to the mountainside, rise into the skies. Water splashes into the village fountain. Berchtesgaden, a Bavarian town located not far from the Austrian border, is a place encircled by Alpine peaks: Summits like the Jenner, the Grünstein and the Kneifelspitze are interspersed with patches of meadows. But there is something more to the town than this postcard setting. It is also home to a hard-working array of high tech. The mountaintops around the town are dotted with transmitters, ones that are capable of exactly reproducing the signals emitted by the Galileo satellite navigation system and that can broadcast them down to the valley situated below. As a result, a gigantic test bed for satellite navigation has been created by this interplay of signals that dance between the peaks and the computing center in the valley: the Galileo Test and Development Environment GATE. »Thanks to Berchtesgaden's location – positioned in a valley basin and surrounded by mountains– the town offers optimal test conditions. As a result, we can cover an area of 65 square meters,« says Georg Kern of the operating company Ifen.
Small Galileo in the Alps, big Galileo in space
GATE specializes in vehicle and pedestrian navigation. »GATE is a real small Galileo. You can use it to find your position on Earth to within just a few meters,« says Alexander Witzel of NavCert, a joint venture of TÜV SÜD and OECON GmbH, that is certifying GATE through the end of 2010. The specialists for navigation and location technology have ensured that every manufacturer always has identical testing conditions and that the broadcast signal exactly matches the future original. With this contract, Witzel has ventured into some uncharted waters. »The challenge was to first put together the certification criteria,« he says. The expert thoroughly believes in the capabilities of Galileo – Europe's contribution to the global satellite navigation system GNS: »This satellite system will be state of the art.«
You can only imagine where the Galileo satellites will orbit: about 23,000 kilometers up in space. Beginning in 2014, 18 satellites are to cover the Earth. From there, the system is to be expanded to 30 satellites. But before Galileo really gets to work, the technology that will bring it to life – route planners, navigation devices in cars or helicopters, survey equipment or transceivers for walkers – has to be tested. »A test bed like GATE is unique around the world,« Kern says. »As a result, two of our engineers were able to land a helicopter at an exact spot just by using Galileo signals.« The Berchtesgaden mountain-rescue service also successfully located »avalanche victims« in snow during test trials.
»Humans are consuming outer space«
Dr. Hubert Reile, Program Director Space at the German Aerospace Center, and his team have their hands full right now. At the moment, two test satellites are in space, GIOVE-A and GIOVE-B. Galileo is monitored by two ground-control centers, one in Oberpfaffenhofen and one in Fucino, about 100 kilometers east of Rome. »The satellites themselves aren't the complicated issue. It's their interplay,« Reile explains. There are also 40 stations that pick up Galileo's signals around the world. »This requires unbelievable coordination,« he says. The technology is far from the only matter that requires coordination: »The problem right now is getting the system up and running with the involvement of 27 sovereign countries in Europe. Each one wants to get the biggest possible piece of the pie.« After all, a lot of money is at stake: The European Commission projects that the world market for satellite-navigation products will climb to €400 billion by 2025. Approximately 3 billion satellite-navigation receivers are to be in operation by 2020. »And there will be applications that we have not even thought of yet,« Reile says.
Galileo is also designed to give Europe independence from the American GPS system. Should GPS be shut down, the electricity-delivery system would fail throughout Europe because all switch points are synchronized through GPS. The European satellite system is designed to be more precise, more reliable and less easy to manipulate. The primary beneficiaries of Galileo will be safety-critical applications requiring the highest levels of reliability: such as landing planes, maneuvering ships and transmitting distress signals. The distance between the satellites, their altitude and their orbit are calculated in such a way that the signals can be received by at least four satellites at all times and from every position on Earth. Using these signals, navigation receivers can determine the exact position. A measurement will be made of the time that the electromagnetic signals take to travel from the satellite to the position on Earth. For this reason, extremely precise atomic clocks are installed in each satellite. The receivers, no matter whether they are in cars, ships or planes, pick up the signals and process them. Their position can be correctly determined to within meters. Most people know virtually nothing about the technology involved in the system. »Humans constantly consume extremely complicated outer-space applications. But most of them don't realize it at all,« Reile says.
Test bed for ships in the Bay of Kiel
Shipping also abandoned celestial navigation years ago in favor of the signals generated by satellites in space. A special facility in the research harbor of Rostock, SEAGATE, enables maritime applications with Galileo signals to be tested. Since May 2008, the ferry »Mecklenburg-Vorpommern« – outfitted with two Galileo receivers – has been plying the route between Rostock and Trelleborg, Sweden. The Warnowmündung section of the harbor is heavily traveled by cruise ships and ferries that are arriving, loading, unloading and departing. Tight schedules and turning maneuvers require very precise position signals. Galileo will not just play a role in ports, though. It will also help ships traveling the high seas to remain on course. »Ships running into reefs or going off course are to become things of the past,« says NavCert Managing Director Martin Grzebellus, who will also certify SEAGATE by the end of 2010. »Until Galileo is transmitting its signals, the world will come to Berchtesgaden or Rostock to conduct tests.