Europe Works Toward Galileo Validation
Tuesday, March 13, 2012 | Comments
Soyuz lifts off from Europe's Spaceport
in French Guiana in October 2011
carrying the first two Galileo in-orbit
validation satellites. Photo courtesy ESA
The European Space Agency (ESA) is working toward a goal of deploying enough satellites and ground equipment to begin the in-orbit validation of its Galileo navigation and positioning system by the end of the third quarter.
The Galileo system is a collaboration of the ESA and the European Commission (EC) to build an independent satellite positioning system under civilian control. The EC is responsible for politics and high-level mission requirements, while the ESA focuses on technical components and the physical deployment of the system. Buildout of the system has slowed during the past decade because of funding issues.
Once completely deployed, the system will consist of 30 satellites in medium earth orbit. The first two satellites that make up the system constellation were launched in October 2011, and two additional satellites are planned for launch around mid-2012. Once four satellites are in orbit, Galileo will have the minimum number of satellites needed to begin to evaluate system performance, the agency said.
Meanwhile, ESA has been working to complete a series of ground stations around the world. It recently completed a remote installation on the main island of the Kerguelen group in the Indian Ocean and deployed stations on the Reunion Islands in the Indian Ocean and New Caledonia in the Pacific Ocean.
The ground infrastructure consists of uplink stations, sensor stations, and two telemetry, tracking and command stations. The network of sensor stations will monitor the system performance for the Galileo Control Centre in Fucino, Italy.
In addition, earlier this month, ESA announced the two satellites planned to launch this summer will carry Cospas-Sarsat satellite relay transponders. Cospas is a Russian acronym that translates to space system for the search of vessels in distress. Sarsat stands for search and rescue satellite-aided tracking.
The system ­— a joint effort of Canada, France, Russia and the United States — makes use of satellites to locate the source of distress calls from radio beacons on ships and aircraft and to alert local authorities. The system also can send back a signal to the distressed party with notification that the distress signal has been received and relayed to authorities.
The ESA’s efforts to build the Galileo system coincide with China’s launch of its homegrown satellite positioning system earlier this year. China’s BeiDou positioning and navigation system is operating in trial mode, while the country launches more satellites to complete its constellation. The system is expected to be fully operational by 2020.
Galileo and BeiDou are responses to the United States’ established and widely used GPS system, which has been operational for nearly two decades, as well as Russia’s Global Navigation Satellite System (GLONASS), which is undergoing an overhaul. In addition to commercial interests, concerns that the United States could block access to the GPS system in a time of crisis or war have prompted other countries to develop their own positioning and navigation systems.
The Galileo system is designed to be interoperable with the GPS and GLONASS systems.
Galileo shares a common concern with the U.S. GPS system that the LightSquared planned hybrid terrestrial and satellite service could interfere with receivers. The EC wrote a letter to the FCC last year detailing the concerns. In February, the FCC prohibited LightSquared from launching service after a U.S. federal agency determined there is no practical method to mitigate harmful interference from the proposed service.
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