Researchers at Delft University of Technology (TU Delft), the Netherlands, succeeded this week in simultaneously tracking the GIOVE-A and GIOVE-B L1 Open Service signals in space, producing the first reported computation of a double-difference carrier phase integer ambiguity resolution on the first two experimental Galileo satellites in orbit.

Researchers at Delft University of Technology (TU Delft), the Netherlands, succeeded this week in simultaneously tracking the GIOVE-A and GIOVE-B L1 Open Service signals in space, producing the first reported computation of a double-difference carrier phase integer ambiguity resolution on the first two experimental Galileo satellites in orbit.

Beginning at 20:12 UTC on July 6, the researchers collected simultaneous ranging measurements to 12 GPS satellites, two geostationary European Geostationary Navigation Overlay Service (EGNOS) satellites, and to two Galileo satellites, GIOVE-A and GIOVE-B.

(NOTE: More detailed information about this research will be available in a technical article in the September-October 2008 issue of Inside GNSS)

A short baseline of a few meters between two identical receivers was set up in the flat and open Delfland area, allowing for a clear reception of the various GNSS signals in space. The measurements, across two Galileo satellites and two receivers, enabled them to form a pure Galileo double-difference. Using the geometry-free approach, the GIOVE-A–GIOVE-B carrier phase cycle double difference ambiguity can be estimated using the pseudorange code measurements.

The accompanying graph shows, for the full joint visibility duration of GIOVE-A and GIOVE-B (96 minutes), the epoch-wise ambiguity estimates. The empirical standard deviation is 3.4 cycles (on L1), which reflects the double difference pseudorange code noise.

According to the researchers, the overall (averaged) ambiguity float estimate is -9.05, which is fixed with large confidence, to the integer value -9. The carrier phase measurements of both GPS and Galileo were found to have similar precision, around 1–2 millimeters (standard deviation; undifferenced).

This achievement was reached in close cooperation with Septentrio Satellite Navigation in Leuven, Belgium. Researchers included Christiaan Tiberius and Hans van der Marel, at TU Delft, and Jean-Marie Sleewaegen and Frank Boon, of Septentrio.

The measurements were collected using two AsteRx1 L1 24-channel GNSS receivers with firmware that allows tracking of the Open Service L1-BC signal of Galileo GIOVE-A and GIOVE-B.

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After completing final tests at the European Space Agency (ESA) space technology center in Noordwijk, The Netherlands, the spacecraft was transported to Baikonur aboard an Antonov An-124 cargo aircraft.

GIOVE-B, the second Galileo in-orbit validation satellite, has arrived safely at the Baikonur Cosmodrome in Kazakhstan, where it is undergoing pre-flight checks in preparation for its launch early on April 26.

After completing final tests at the European Space Agency (ESA) space technology center in Noordwijk, The Netherlands, the spacecraft was transported to Baikonur aboard an Antonov An-124 cargo aircraft.

A team of engineering staff made up of personnel from ESA and the industrial consortium that developed GIOVE-B will now check out the satellite and its associated ground support systems. ESA has set up a GIOVE-B launch website at <http://www.esa.int/SPECIALS/GIOVE-B_launch>.

Once it is ready for its mission, GIOVE-B will be mated with the Fregat upper stage of the launcher and then covered with the fairing (nosecone) that will protect it as the launch vehicle climbs through the Earth’s atmosphere.

As the date for launch approaches, the upper composite, made up of GIOVE-B, the Fregat and the fairing, will be transported by rail to the integration building and mounted on the third stage of the Soyuz FG launcher.

The completed launcher, which is assembled in a horizontal configuration, will then move by rail to the launch pad, where it will be raised into the vertical position, ready for lift off.

The first experimental Galileo satellite, GIOVE-A, was launched on December 28, 2005, with a mission to characterize and validate the critical technologies required for Galileo. GIOVE-A remains in service, but has reached the end of its two-year design life.

GIOVE-B will carry a high-precision passive maser clock — the most accurate clock ever flown in space — and will be capable of triple-channel transmission of navigation signals.

Based on the experience with GIOVE-A and – B, ESA will launch four operational satellites in 2010 to validate the Galileo concept with both segments: space and the related ground infrastructure. Once this In-Orbit Validation (IOV) phase has been completed, the remaining 26 satellites will be installed to reach the Full Operational Capability (FOC) by 2013.

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That would move an additional €2.4 to €3 billion onto the public tax burden, but it might also represent the quickest route to completion of the GNSS project backed by the European Union (EU) and the European Space Agency (ESA).

A sea change appears to be taking place in Europe’s Galileo program as its political masters prepare to transform the struggling public-private partnership (PPP) into a more traditional institutional program wholly sponsored by the public sector.

That would move an additional €2.4 to €3 billion onto the public tax burden, but it might also represent the quickest route to completion of the GNSS project backed by the European Union (EU) and the European Space Agency (ESA).

The move follows the collapse of negotiations between the European GNSS Supervisory Authority (GSA) and an eight-member consortium of private companies that sought a 20-concession to complete and operate Galileo. A European source close to the negotiations confirmed the new directions for the program to Inside GNSS.

At a March 22 session, the EU Transport Council gave the consortium until May 10 to incorporate and get negotiations back on track, at the same time asking its executive arm, the European Commission (EC) — assisted by the GSA and ESA — to come up with alternative options for handling the project.

On May 11, the GSA Administrative Board concluded, “We did not see relevant progress at the level that the Council expected,” according to GSA Executive Director Pedro Pedreira. That assessment and a discussion of alternatives have gone back to the transport ministers.

The officials are expected to re-visit the Galileo situation at a Transport Council meeting in early June. Jacques Barrot, EC vice-president and transport commissioner, is expected to announce the options under consideration by the EC on May 16.

The Alternatives. Reuters UK, citing a draft of an EC report that the news service said it had obtained, identified the preferred option as a public takeover the project now and issuance of a new tender for a private operator once the Galileo space and ground infrastructure is built. Projected completion of the system under that scenario would be the end of 2012.

In that case, ESA would probably act as the prime contractor for the project, extending its role beyond the in-orbit validation (IOV) phase. IOV includes construction of a ground monitoring and control segment and launch of the first four operational Galileo satellites beginning in 2009, as well as three experimental spacecraft, the first of which went into orbit in December 2005. ESA currently is overseeing a billion-euro IOV contract with the European Satellite Navigation Industries (formerly Galileo Industries).

A sizable question mark beside this option is whether ESA, with its background in scientific and research projects, can execute a time-sensitive commercial project with greater consequences for failing to deliver products and services to market as needed.

Another option, according to Reuters, would have the public sector launch 18 satellites and then turn the project over to industry to launch the remaining 12 — delaying completion until a year later. The final option would continue on the present PPP, prospectively delaying a fully operational system until mid-2014 at the earliest.

Since the March 22 ultimatum, the consortium members agreed to incorporate a Galileo Operating Company (GOC) to sign a so-called “head of terms” agreement with the GSA outlining the concession contract. However, consortium members apparently continued to wrangle among themselves, with some aerospace manufacturers speculating that they could do better under a new conventional program contract.

Then, in early May, the consortium apparently sent the commission a letter requesting additional time and incentives to resolve the stand-off.

GIOVE-A Nav Message

Despite the political situation, technical progress on Galileo continues. Early in May, ESA announced that the system’s first experimental satellite, GIOVE-A, had successfully transmitted its first navigation message.

The nav message contains the information needed by user receivers to calculate their position. Prior to reaching this milestone, the satellite had been broadcasting only the data needed for measuring the receiver-to-satellite distance.

The message was created by the navigation signal generator unit on board GIOVE-A, using content prepared by the GIOVE Mission Segment. The nav message was uplinked from the Guildford ground station in England operated by Surrey Satellite Technology Ltd. and then transmitted from the spacecraft to the users.

The objective of the test was to demonstrate an end-to-end link between the mission segment and user receivers. The navigation message is being generated for demonstration purposes only — no service guarantee is provided.

Copyright 2007 Gibbons Media and Research LLC

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Risk allocation, avoidance, and management are the watchwords of the day as the contract negotiation for the Galileo concession moves into its endgame.

Talks have gone on for more than a year between the Galileo Joint Undertaking (GJU) and a superconsortium of leading European industrial entities, financial institutions, and communications service providers — including former competitors and a late-arriving German consortium integrated into the private sector team only last December.

“Love at second sight,” is how Martin Ripple, director of EADS Space’s Galileo program and chief negotiator in the contract talks, describes the merger of the iNavSat, Eurely, and TeleOp teams (See “Perils and Pearls of Galileo,” January/February 2006, Inside GNSS).

The consortium and GJU are well past a December 2005 goal for concluding a 20-year agreement that will guide deployment and operation of the European GNSS, but most participants now predict that a deal will not be signed much earlier than the end of this year.

Earlier delays in reaching agreements among European Union (EU) governments, ESA, the European Commission acting as the EU’s executive arm, and private sector companies finally led the project sponsors to acknowledge that a fully operational Galileo system would not be completed until 2010, two years later than originally planned.

The GJU will cease operations shortly after the signing of a concession contract, turning responsibility for monitoring contract fulfillment over to a Galileo Supervisory Authority (GSA) still in the process of being set up under the direction of Pedro Pedreira. Although not directly involved in the contract negotiations, the GSA is regularly briefed on the progress of talks.

Work on the Galileo deployment continues apace, however, following a €950-million contract signed by the European Space Agency (ESA) and Galileo Industries in January. The contract will continue rollout of the ground and space infrastructure, including four in-orbit validation (IOV) satellites to be launched in 2008.

Meanwhile, the first Galileo IOV experimental satellite, launched last December, began transmitting signals on January 12. According to ESA officials and Surrey Satellite Technology Ltd., which built and is operating the satellite, the GIOVE-A is performing well and expected to achieve its primary mission: securing the radio spectrum allocations sought by the Galileo program. The spacecraft must operate successfully in 17 frequency modes to achieve the complete Galileo filing with the International Telecommunications Union.

In March, ESA officials told the BBC News in London that successful results from GIOVE-A mean that the second experimental spacecraft, GIOVE-B, probably won’t need to be launched until this autumn. Also, late in March members of a bilateral EC/U.S. technical working group reached agreement on design of the new optimized civil signals in which the signal structure of the Galileo L1 OS will be the same as the GPS L1C.

Back in Brussels. Many aspects of the concession contract have already been worked out, leaving the complex and crucial issue of sizing, allocating, and providing against the financial risks associated with Galileo.

The stakes are high, and some associated tension is manifesting itself publicly.

Heinz Hilbrecht, director for trans-European networks in the EC Directorate-General for Energy and Transport, says, “The Commission will not sign up to a deal where risk is shifted to the EC. Have no illusions — the EC will not accept a deal that shifts all the risk to the public sector. We want the private sector to do what they say the do well: act as an entrepreneur rather than simply ensuring an acceptable return on an investment. We want a real [public/private partnership]; without that, there will be no deal.”

Carlo des Dorides, Head of GJU Concession Division, says the discussions have identified nine categories of risk in the project: cost overruns, completion, revenues (market), performances, design (interface between IOV and Concession program), overall risk coverage (spare, contingency, insurance), deployment program, compensation on termination, and replenishment.

GJU and consortium members agree, however, that only three of these pose serious challenges: the size of the market and prospective revenue sources for the concessionaire, liability risks, and the terms and timing of the hand-over of project management from ESA to the concessionaire.

The current business model identifies €8.5 billion in prospective concession revenues over the 20-year term of the contract, against €7 billion in costs. However, large unknowns revolve around the portion of the Galileo market that will be unregulated and accessible to the concession’s revenue measures.

As for liability against potential lawsuits for damages that Galileo users may bring, the concession has proposed a tiered risk-pool arrangement with what it believes to be the vast majority of exposure covered by insurance purchased by the concessionaire. It is asking the public sector to deal with financial risks above that level.

The transition from ESA to the concession is complicated by the fact that the design of the system took place under one contract (ESA/Galileo Industries) while another contract (consortium/GJU/GSA) will implement it.

One observer close to the process says the GJU hoped to have common position worked out with the concessionaire on the three key risk issues to take to European Transport Council for approval at its March 27 meeting. That would allow the two sides to resolve the lesser risk factors and finish the concession contract proposal, which has to be reviewed and approved by council before being signed and monitored by the GSA.

In the Same Boat? The strength of the two sides’ relative political positions are deeply intertwined as a result of the years of public and private process that have led up to the current situation.

On the one hand, the GJU would seem to be at a disadvantage, having only one candidate concessionaire after the competitors merged (reportedly with some quiet encouragement by the public sector). Moreover, Galileo has gained such a high profile — effectively serving as the flagship project for a unified European space initiative — that considerable political “face” would be lost with a collapse of the project now.

On the other hand, the would-be private partners have invested years of effort and budget to reach this point, and they are recipients of EC and ESA contracts for programs besides Galileo. As one observer noted, “The consortium will not abandon the project because they have to come back to the EC for other programs and project funding.”

Ripple acknowledges the complexity of the deal-making that sometimes has as many as 18–20 participants in the room — although only two directly negotiating and the remainder serving as information resources and de facto counselors on specific topics.

Asked if he “saw a danger that this concession contract negotiation could fail, Ripple says, “I don’t think so. We have advanced the discussion well beyond the point of no return. We have a commitment to sign an agreement by the end of the year, and I don’t think it can fail.”

“We can do it [reach agreement on a contract],” agrees des Dorides. It will be quite a challenge, but we can do it.”

Copyright 2006 Gibbons Media and Research LLC

The post Galileo: the Concession Merry-Go-Round appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

European Space Agency (ESA) and Surrey Satellite Technology Ltd.(SSTL) operators have completed the on-orbit preparations and activated the navigation payload for GIOVE-A, the first Galileo satellite launched December 28.

European Space Agency (ESA) and Surrey Satellite Technology Ltd.(SSTL) operators have completed the on-orbit preparations and activated the navigation payload for GIOVE-A, the first Galileo satellite launched December 28.

Galileo RF transmissions began January 12, and ESA and SSTL operators have successfully received and decoded the payload signals.

GIOVE A was placed in orbit at an altitude of 23,260 kilometers by a Russian Soyuz-Fregat rocket operated by Starsem that lifted off from the Baikonur cosmodrome in Kazakhstan.

The 600-kilogram satellite, built for ESA in just 30 months and for €28 million by SSTL of Guildford, United Kingdom, has three primary objectives: securing use of the frequencies allocated by the International Telecommunications Union (ITU) for the Galileo system, demonstrating critical technologies for the navigation payload of future operational Galileo satellites, and assessing the radiation environment of the orbits planned for the Galileo constellation.

GIOVE A will transmit in the frequencies allocated to Galileo: E2, L1, E1, E5, and E6. Evaluation of the signals is being made through the Chilbolton Observatory Facilities for Atmospheric and Radio Research in the UK and ESA’s station in Redu, Belgium.

A Galileo Experimental Test Receiver developed by Belgian GNSS company Septentrio Satellite Navigation NV is one of the receivers that is being used to verify the acquisition, tracking, and noise characteristics of all transmitted signals.

Formerly known as GSTB-V2/A, the GIOVE A satellite is carrying two redundant, small-size rubidium atomic clocks built by Temex Neuchatel Time (Switzerland), each with a stability of 10 nanoseconds per day, and two signal generation units — one built by SSTL capable of generating a simple Galileo signal and the other built by Alcatel Alenia Space (Italy) that provides a more representative Galileo signal.

The signals are broadcast through an L-band phased-array antenna designed to cover all of the visible Earth under the satellite. Two additional instruments monitor the types of radiation to which the satellite is exposed during its two-year mission.

The various Galileo signal modes will now be generated sequentially using the various GIOVE A payload chains. Payload commissioning activities should be completed by mid-February.

Additional measurement campaigns will then be carried out to assess the medium earth orbit radiation environment, characterize the performance of the on-board clocks, and perform signal-in-space experimentation.

A second, larger and more advanced demonstrator satellite, GIOVE B built by the Galileo Industries consortium, will be launched later this year in the spring. (An American news outlet reported an April 14 launch, but an ESA official said that it was too early to confirm a specific date, which would depend on the performance of GIOVE A.)

In addition to a rubidium clock, GIOVE B will carry a passive hydrogen maser (PHM), an extremely accurate clock that has been developed under ESA contract. The PHM will be the first of its kind to be flown in space and have its performance tested in a realistic environment.

GIOVE A is broadcasting an experimental signal through two separate channels at a time. GIOVE B will transmit signals through three separate channels.

ITU rules require that, once a satellite is transmitting, transmissions cannot be interrupted for more than four months. For this reason, the GIOVE B satellite will provide a back-up system once launched to ensure that these crucial frequencies are secured, according to SSTL.

After the two GIOVE spacecraft are checked out, four operational satellites built by Galileo Industries will be launched by 2008 to validate the basic Galileo space and related ground segments.

Once this in orbit validation (IOV) phase is completed, the remaining satellites will be launched to achieve full operational capability by 2010. ESA signed a contract with Galileo Industries on January 19 to provide continuing management and technical services during the IOV phase.

For its Galileo role beyond the IOV phase, ESA is currently preparing what is called “Galileo evolution” related to the next generation of the system,” says Dominique Detain, communications manager for ESA’s navigation department.

The December 28 launch represents the culmination of a process to develop a European GNSS that began more than a decade ago.

Copyright 2006 Gibbons Media and Research LLC

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