Galileo is Europe’s independent satellite navigation system under civilian control and interoperable with GPS and GLONASS.
With four operational satellites working well in orbit as of October 2012, ESA has ended the mission of the Galileo In-Orbit Validation Element (GIOVE) satellites.
The European version of the common civil signal is the composite binary offset carrier (CBOC) modulation, which is being transmitted on the E1 Open Service signal. The CBOC modulation is the result of multiplexing a wideband signal, BOC (6,1) with a anrrow band signal, BOC(1,1), in such a way that 1/11 of the power is allocated on average to the high-frequency component.
To reach operational status, Galileo needs a constellation of 30 satellites and an associated network of ground stations spread all around the globe. This phase was confirmed in 2007 with the decisions taken by the European Union (EU), which agreed on a financing package of €3.4 billion Euros and proposed to entrust the European Space Agency (ESA) with the full deployment of Galileo by 2013. This goal has been delayed many times. The project has been led this far by a 50-50 partnership between the European Union through the auspices of its executive branch, the European Commission (EC), and ESA.
As proposed, Galileo would transmit a variety of signals and signal designs in support of open, commercial, safety of life, and public regulated services (encrypted). Under a landmark 2004 agreement with the United States, the open Galileo signal operating near the same frequency as the GPS L1 broadcast (1575.42 MHz) would have a similar signal structure as the new GPS civil signal (L1C). That would simplify the design and manufacturing of user equipment that could process signals from satellites of both GNSS systems.
FIRST LAUNCH 2005
Successful launch in December 2005 of GIOVE-A, the first experimental Galileo satellite, marked the culmination of a process that began almost exactly 13 years earlier.
The next step is well under way, with GIOVE-B - the second experimental satellite — finishing its preparations for launch at ESA's test facilities in Noordwijk, The Netherlands.
On January 19, 2006 the European Space Agency and Galileo Industries GmbH (now European Satellite Navigation Industries or ESNI), the European company steering a consortium of more than 100 subcontractors, signed a €950 million (US$1.15 billion) contract to pave the way for the operational deployment of Galileo.
The contract called for a mini-constellation of four satellites backed by an extensive network of tracking and control stations that will validate the design of the Galileo space and ground infrastructure. Four satellites are the minimum required to generate three-dimensional positioning and precise timing over the selected showcase sites.
In December 1992, however, Galileo was just a glimmer in a few visionaries’ eyes. That was the month that two European Commission (EC) directorates-general — those for transport and science, research, and development – decided to fund a modest study of satellite navigation options for Europe.
The intervening years produced a kind of programmatic version of an old-fashioned cliffhanger serial movie in which the heroine is placed in a perilous situation, only to be rescued at the beginning of the next episode. With Galileo, the political and organizational challenges have long eclipsed the technical ones.
The most recent peril appeared early in 2007, when the program faced the collapse of the Public-Private Partnership (PPP), the core of a plan in which private investment would beprovide two-thirds of the investment needed to deploy Galileo’s infrastructure.
Shortly thereafter, the European Transport Council directed the European Commission (EC) Directorate-General (DG) Energy and Transport to begin work on a comprehensive proposal for a Galileo program completely financed by the public sector. The EC submitted its proposals to the transport council in September 2007, which generally reaffirmed its commitment to the Galileo program in an October 2, 2007, meeting.
In its first look at the EC plan, the council confirmed its intention “to take an integrated decision on the European GNSS before the end of . More problems arose with the postponement in October 2007 of the launch of GIOVE-B, the second Galileo In-Orbit Validation Element satellite, until at least March 2008.
COMMON SIGNAL AGREEMENT
That and previous delays, however, have allowed the European Space Agency and its prime contractor for GIOVE-B, the European Satellite Navigation Industries (ESNI), to retrofit the spacecraft’s signal generator to be able to broadcast the new multiplex binary offset carrier (MBOC) modulation common civil signal agreed to on July 26,2004, by the United States and Europe.
MBOC will allow receivers to track the GPS and/or Galileo signals with higher accuracy, even in challenging environments. More generally, the IOV phase has also been set back under the European Commission’s October proposal: from completion in 2008 to just beginning launch of four IOV satellites in 2009.
Aside from the political issues, difficulties experienced by ESA in managing ESNI have also contributed to the delay. ESA officials have also indicated that it makes no sense to put the IOV spacecraft into orbit until a plan and timeline for launch of Galileo’s remaining 26 satellites has been worked out.
Copyright 2012 Gibbons Media & Research LLC