Surveyors guide-all Surveyors. Search Surveyors for advice.

Articles

The States of GPS

GPS - Global Positioning System

This is defined as a system of satellites around the Earth that broadcast the time via radio signals from an internal atomic clock. GPS devices can receive the signals from multiple satellites, and by measuring the time it took the signal to arrive they can determine their current position, velocity, and time information from any point on the Earth.

There are three satellite systems in or near to operational availability. NAVSTAR was originally operated by the United Stated military but is currently the only system that has complete coverage and is freely available to all users. GLONASS was a system initiated by the Union of Socialist Soviet Republic but which has not been fully functional for some years but is now gained a renewed interest. GALILEO is in the early stages of signal testing and planning. It is to be operated by a consortium of European state interests.

NAVSTAR

The Global Positioning System (GPS) is a satellite navigation system developed and maintained by the U.S. government. Initially designed for military applications, the increasing number of civilian users has developed numerous applications using GPS.

On March 29, 1996, a Presidential Decision Directive (PDD) was signed by President Clinton that described GPS as an international information utility. The PDD included the following directives:

• The U.S. government will continue to operate, maintain and provide basic GPS signals worldwide, free of direct user fees.

• The U.S. will advocate the acceptance of GPS and it s augmentations as a standard for use by initiating international discussions and agreement with Japan and Europe

On December 15, 2004 President Bush Authorized a new U.S. GPS Policy “Fact Sheet: U.S. Space-Based Positioning, Navigation, and Timing Policy New national policy authorized on December 8, 2004”. Issued by Office of Science and Technology Policy Executive Office of the President Washington, D.C. which supersedes Presidential Decision Directive/National Science and Technology Council-6, U.S. Global Positioning System Policy, dated March 28, 1996.

The scope included security, modernisation and sustainment of the system and international cooperation with foreign space-based positioning, navigation, and timing services, including augmentation services.

• "Interoperable" refers to the ability of civil U.S. and foreign space-based positioning, navigation, and timing services to be used together to provide better capabilities at the user level than would be achieved by relying solely on one service or signal;

• "Compatible" refers to the ability of U.S. and foreign space-based positioning, navigation, and timing services to be used separately or together without interfering with each individual service or signal, and without adversely affecting navigation warfare; and

• "Augmentation" refers to space and/or ground-based systems that provide users of space-based positioning, navigation, and timing signals with additional information that enables users to obtain enhanced performance when compared to the un-augmented space-based signals alone. These improvements include better accuracy, availability, integrity, and reliability, with independent integrity monitoring and alerting capabilities for critical applications.

Recognising that the Global Positioning System had grown into a global utility with multi-use services integral to national security, economic growth, transportation safety, and an essential element of the worldwide economic infrastructure, in 2000, the United States discontinuing the deliberate degradation of accuracy for non-military signals, known as Selective Availability. It now also recognises that emerging foreign space-based positioning, navigation, and timing services could enhance or undermine the future utility of the Global Positioning System.

The commitment to improve and maintain the Global Positioning System, augmentations, and backup capabilities to meet growing national, homeland, and economic security requirements, for civil requirements, and to meet commercial and scientific demands requires the existing management mechanisms to be modified to accommodate a multi-use approach to program planning, resource allocation, system development, and operations. In this the United States Government shall:

• Provide uninterrupted access to U.S. space-based global, precise positioning, navigation, and timing services for U.S. and allied national security systems and capabilities through the Global Positioning System, without being dependent on foreign positioning, navigation, and timing services;

• Provide on a continuous, worldwide basis civil space-based, positioning, navigation, and timing services free of direct user fees for civil, commercial, and scientific uses, and for homeland security through the Global Positioning System and its augmentations, and provide open, free access to information necessary to develop and build equipment to use these services;

• Improve capabilities to deny hostile use of any space-based positioning, navigation, and timing services, without unduly disrupting civil and commercial access to civil positioning, navigation, and timing services outside an area of military operations, or for homeland security purposes;

• Improve the performance of space-based positioning, navigation, and timing services, including more robust resistance to interference for, and consistent with, U.S. and allied national security purposes, homeland security, and civil, commercial, and scientific users worldwide;

• Maintain the Global Positioning System as a component of multiple sectors of the U.S. Critical Infrastructure, consistent with Homeland Security Presidential Directive-7, Critical Infrastructure Identification, Prioritization, and Protection, dated December 17, 2003;

• Encourage foreign development of positioning, navigation, and timing services and systems based on the Global Positioning System. Seek to ensure that foreign space-based positioning, navigation, and timing systems are interoperable with the civil services of the Global Positioning System and its augmentations in order to benefit civil, commercial, and scientific users worldwide. At a minimum, seek to ensure that foreign systems are compatible with the Global Positioning System and its augmentations and address mutual security concerns with foreign providers to prevent hostile use of space-based positioning, navigation, and timing services; and

• Promote the use of U.S. space-based positioning, navigation, and timing services and capabilities for applications at the Federal, State, and local level, to the maximum practical extent.

The Management of Space-Based Positioning, Navigation, and Timing Services is to be a permanent National Space-Based Positioning, Navigation, and Timing Executive Committee. The Executive Committee will be co-chaired by the Deputy Secretaries of the Department of Defense and the Department of Transportation or by their designated representatives. The Secretaries of Defense and Transportation shall develop the procedures by which the Committee shall operate.

The Secretary of State shall:

• In cooperation with the Secretary of Defense, the Secretary of Transportation, and other Departments and Agencies promote the use of civil aspects of the Global Positioning System and its augmentation services and standards with foreign governments and other international organizations;

• Take the lead for negotiating with foreign governments and international organizations regarding civil and, as appropriate and in coordination with the Secretary of Defense, military positioning, navigation, and timing matters, including but not limited to coordinating interagency review of:

• Instructions to U.S. delegations for bilateral and multilateral consultations relating to the planning, management, and use of the Global Positioning System and related augmentation systems; and

• International agreements with foreign governments and international organizations regarding the planning, operation, management, and/or use of the Global Positioning System and its augmentations; and

• Modify and maintain, in coordination with the Secretaries of Defense, Commerce, and Energy, the Director of Central Intelligence, and the Administrator of the National Aeronautics and Space Administration, the Sensitive Technology List created by U.S. Commercial Remote Sensing Space Policy, dated April 25, 2003. In particular, include sensitive technology items and/or information related to positioning, navigation, and timing applications.

GPS World reported on Feb 1, 2006 that a joint U.S. Air Force/Lockheed Martin team declared the first modernized GPS satellite, a IIR-M which had been launched in late September, to be fully operational for GPS users around the globe following an extensive on-orbit testing of the spacecraft s new military and civilian signals.

The spacecraft features a modernized antenna panel that provides increased signal power to receivers on the ground, with two new military signals for improved accuracy, enhanced encryption and anti-jamming capabilities for the military, and a second civil signal that will provide users with an open access signal on a different frequency.

The satellite was declared operational on December 16 by Air Force Space Command s 2nd Space Operations Squadron (2 SOPS) at Schriever Air Force Base, Colorado. The GPS IIR team is now gearing up for the launch of the second modernized IIR satellite scheduled for liftoff in early 2006. Lockheed Martin has a contract to modernize eight IIR satellites.

In the intervening period of modernisation, users have access to an enhanced GPS correction system provided in the US and Canada by WAAS, a wide area augmentation system. In Mar 27, 2006, the FAA s announced that WAAS in the northeastern United States and eastern Canada may be significantly inhibited by relocation of WAAS-broadcasting satellite AOR-W before the new PanAmSat becomes fully operational in fall 2006. This also caused unease in some surveying organizations. Based on tests completed last year, before anyone knew that AOR-W would relocate to 142W longitude, these organizations replaced legacy GPS mapping units using post-processing and the Coast Guard NDGPS with high-performance WAAS-enabled mapping receivers. The FAA notice doesn t tell the full story, however, as two new WAAS broadcasting satellites were launched the previous fall. PanAmSat (133W) began broadcasting in test mode with corrections full-time this March, and Telesat (107W) is scheduled to begin the same mode on or around April 1, 2006. The FAA announcement does not take into account either of these broadcasting satellites.

If these test signals are considered, there will be no degradation in WAAS visibility. In fact, users in the northeastern United States and eastern Canada will enjoy dual WAAS satellite coverage. WAAS satellite visibility in central and western North America has improved in the past 60 days with the new test signals and relocation of AOR-W. However, the FAA won t certify the accuracy/reliability of the new satellites until after extensive testing. Until then, non-aviation receivers may use the signals at their discretion —the same mode WAAS operated in prior to its July 2003 commissioning. Also, non-aviation WAAS receivers may not be configured to use the new test signals; check with the manufacturer.

Further in Mar 1, 2006, The U.S. Air Force GPS Joint Program Office — with participation by Lockheed Martin, the National Geospatial-Intelligence Agency, the Aerospace Corporation, and Applied Research Laboratories, the University of Texas at Austin — has upgraded the software processing and modelling for GPS, enhancing the Air Force s ability to monitor GPS satellites and improve system accuracy 10-15 percent for users worldwide. Tracking data from the six GPS monitoring stations are now being added to data from the U.S. Air Force network to generate the real-time operational orbits for GPS. NGA is feeding its monitor station data in real-time to the GPS Master Control Station (MCS) at Schriever Air Force Base in Colorado, where they are input to the Kalman filter that ultimately produces the broadcast navigation message. The recently completed update, named the Legacy Accuracy Improvement Initiative (L-AII), doubles the amount of navigation data collected and provided to Air Force operators. For more details and technical background on the initiative, see the “New, Improved GPS” article. The L-AII upgrade allows the integration of data from 14 National Geospatial Intelligence Agency (NGA) monitor stations with data from six existing GPS monitor stations. The L-AII update has incorporated improvements in a variety of scientific knowledge areas, including: numerical standards, geopotential, monitor station site displacement, tidal variations in the earth s rotation, tropospheric delays, and satellite solar radiation pressure.

From August 18 to September 7, NGA data from Washington, D.C., England, Argentina, Ecuador, Bahrain, and Australia have been systematically added to the routine data processing at the MCS. These stations complement the Air Force stations in Colorado, Florida, Hawaii, Kwajalein, Ascension, and Diego Garcia. The combined 12-station network will allow satellite operators to see every GPS satellite in the 29-satellite constellation continuously from at least two stations. When five more NGA sites are added in the future, the MCS will see every satellite from at least three stations. This will also greatly improve satellite integrity monitoring at the MCS. Inclusion of the NGA stations is the third of a five-phase process. During the first two phases, operational software and modelling were improved. Phase four tests the MCS backup facility in Gaithersburg, Maryland. Phase five will be a follow-on modelling upgrade.

Richard Langley, professor of geodesy and geomatics engineering at the University of New Brunswick, reports, “I ve done initial testing comparing the 3D rms accuracy of the broadcast orbits with those of the International GNSS Service. Tests show that the improvement in broadcast orbits accuracy between August 1-17, before the upgrade process commenced, and 8-11 September, the first few days after the upgrade was completed, was about 25 percent. More testing is needed to see if this level of improvement in the orbits is maintained or it turns out to be a little lower. In any case, I think that the improvement in civil-user position fix accuracy will be higher than the 3 percent stated at CGSIC.”

NGA staff reports that “After some internal discussions at NGA, we would add that the 15-20 percent improvement in the real-time broadcast orbit and clock accuracies is a composite of the new NGA data and the modelling improvements, and the figure may be somewhat optimistic. Note also that these are orbit improvements and do not translate directly into URE improvements.”

GALILEO

On the 22 June 2004, the European Commission announced GPS/GALILEO: a cooperation model for a global endeavour. This explained the aims and stated intentions of the programme.

• GALILEO is the international European programme for radio navigation by satellite

• It is the first large space project jointly developed by the European Union and ESA.

• Proposed by the European Commission in February 1999

• Jointly developed with the European Space Agency

• Based on a constellation of 30 satellites on 3 circular orbits at a height 24000 Km

• at the service of several other policies (e.g. transport, agriculture, fisheries, law enforcement, taxation, customs, …);

• a new example of public-private partnership;

• owned by civil players

European Commission responsibility covers

• the political dimension

• the high-level mission requirements

• studies on the overall architecture, the user needs and economic benefits

• legal, institutional, standardisation, certification and regulatory issues

• international negotiations

European Space Agencies s responsibility covers:

• the definition of the system,

• the development and in-orbit validation of space segment

• the development and validation of related ground element.

• the development and validation on new technologies

Phases of the programme

• Development and Validation Phase:

actions: development of satellites and of the ground component, in-orbit validation

duration: 2002-2005

• Deployment Phase:

actions: fabrication and launch of satellites, completion of the ground segment set-up

duration: 2006-2007

• Exploitation Phase:

Futher developments included the initiation of The Joint Undertaking

• Created by a EU Council decision

• Management of the development phase

• Prepares the concessionaire selection

Concessionaire for deployment and exploitation

• Launch of the phase of concessionaire selection for the deployment and exploitation

• Negotiation and choice in progress

Supervising authority

• Management of public interests related European navigation programme

• Licensing authority for the system

GALILEO/GPS cooperation agreement

• 4 years of negotiation

• 24-25 February 2004 : agreement reached on all issues of substance

• Highly satisfactory results for users of GALILEO and GPS worldwide

• Objective to sign by the EU-US Summit on June 26 2004

• Agreement on a common baseline for signals, whilst retaining full flexibility to improve them, together or individually

• Galileo + GPS = future de facto world standard for open signals in the global positioning market

• Each partner can associate independently third parties for the development of its contribution

• Radio frequency compatibility to be maintained in the evolution of either system

The Agreement recognises both sides as equal partners and create optimal conditions for respective:

• Independency

• Compatibility

• Redundancy

Coordinated use of both infrastructures will offer real advantages in terms of quality of services, should one of the systems become unavailable

Users will be able to use both systems with the same receiver

How Galileo differs

Announcements on the 17 March 2005 heralded the high expectations of the European system as Europe s own global navigation satellite system, under civilian control, and providing a highly accurate, guaranteed global positioning service. It will be inter-operable with GPS and GLONASS, the two other global satellite navigation systems.

A user will be able to take a position with the same receiver from all of the satellites in any of the combinations. Thus offering dual frequencies as standard, Galileo receivers will deliver real-time positioning accuracy down to the metre range, which is unprecedented for a publicly available system.

It will guarantee availability of the service under all but the most extreme circumstances and will inform users within seconds of a failure of any satellite. This will make it suitable for applications where safety is crucial, such as running trains, guiding cars and landing aircraft.

The first experimental satellite, part of the so-called Galileo System Test Bed (GSTB) will be launched in the second part of 2005. The objective of this experimental satellite is to characterize the critical technologies, which are already under development under ESA contracts. Thereafter up to four operational satellites will be launched in the timeframe 2005-2006 to validate the basic Galileo space and related ground segment. Once this In-Orbit Validation (IOV) phase has been completed, the remaining satellites will be installed to reach the Full Operational Capability (FOC) in 2008.

The fully deployed Galileo system consists of 30 satellites (27 operational + 3 active spares), positioned in three circular Medium Earth Orbit (MEO) planes in 23616 km altitude above the Earth, and at an inclination of the orbital planes of 56 degrees with reference to the equatorial plane. Once this is achieved, the Galileo navigation signals will provide a good coverage even at latitudes up to 75 degrees north, which corresponds to the North Cape, and beyond. The large number of satellites together with the optimisation of the constellation, and the availability of the three active spare satellites, will ensure that the loss of one satellite has no discernible effect on the user.

Two Galileo Control Centres (GCC) will be implemented on European ground to provide for the control of the satellites and to perform the navigation mission management. The data provided by a global network of twenty Galileo Sensor Stations (GSS) will be sent to the Galileo Control Centres through a redundant communications network. The GCC s will use the data of the Sensor Stations to compute the integrity information and to synchronize the time signal of all satellites and of the ground station clocks. The exchange of the data between the Control Centres and the satellites will be performed through so-called up-link stations. Five S-band up-link stations and 10 C-band up-link stations will be installed around the globe for this purpose.

As a further feature, Galileo will provide a global Search and Rescue (SAR) function, based on the operational Cospas-Sarsat system. To do so, each satellite will be equipped with a transponder, which is able to transfer the distress signals from the user transmitters to the Rescue Co-ordination Centre, which will then initiate the rescue operation. At the same time, the system will provide a signal to the user, informing him that his situation has been detected and that help is under way. This latter feature is new and is considered a major upgrade compared to the existing system, which does not provide a feedback to the user.

The European Space Agency (ESA) has a fund of € 950 million for the development and construction of the first four Galileo constellation satellites and part of the ground infrastructure, including full subsystem testing, to Galileo Industries. The contract covers the development and construction of the first four Galileo constellation satellites and part of the ground infrastructure for Galileo, including the full testing of the subsystem.

EADS Space, a founder member and shareholder of the GaIn consortium (with project partners Alcatel, Finmeccanica, Galileo Sistemas y Servicios, and Thales) will handle almost one-fifth of the contract. EADS Space subsidiary EADS Astrium will build the first four constellation satellites.

This stage of the contract appears to validate Germany s call, voiced in public and private forums over the last year, for a large share of program work. The multinational EADS (European Aeronautic Defense and Space) is based in Schiphol, the Netherlands, but the company s Ottobrunn, Germany facility will undertake the largest portion of the work.

The In Orbit Validation (IOV) phase is designed to test the satellite system under real mission conditions. Between now and 2008, four satellites — the minimum number required to verify the accuracy of the positioning signals — will be delivered.

During the IOV phase, EADS Astrium will assume system leadership for the space segment and take overall responsibility for the construction of the four satellites and design and manufacture the attitude control system. With Dutch Space, a future EADS Space subsidiary based in the Netherlands, EADS Astrium will also provide the solar arrays for the satellites. Propulsion units will come from EADS Space Transportation in Lampoldshausen, Germany.

Responsibility for the onboard payload and the ground control segment lies with EADS Astrium in the United Kingdom. The Portsmouth division will design and manufacture the navigation payload and solid state power amplifiers.

Headquarters of the Galileo Concessionaire will be located in Toulouse, France, and the Operations Company in London, United Kingdom. Two control centres (constellation and mission) will be located in Germany and Italy, with a backup control centre in Spain.

Meanwhile, the GIOVE-A testbed satellite continues transmission of Galileo signals from medium Earth orbit. ESA, Septentrio, and Surrey Satellite Technology Limited maintain a proprietary silence over signal testing results. The second satellite, GIOVE-B, takes final integration and testing at the Rome facilities of Alcatel Alenia Space, prior to moving to the European Space Research and Technology Centre (ESTEC) for environmental test, and launch later this year.

In June 27, 2005, acceptance by the Galileo Joint Undertaking (GJU) of the joint bid by two formerly competing consortia, Eurely and iNavSat. Core members of the two consortia -- Eurely, with constituents Aena, Alcatel, Finmeccanica, and Hispasat; and iNavSat with its partners EADS Space, Inmarsat, and Thales -- understandably wish to move forward as soon as prudently possible. They stand to build, in some cooperative configuration or other, 26 satellites to complete the system after four initial satellites have gone aloft for operation validation. They will also operate the Galileo concession for 20 years. European Union (EU) member states, have already provided 400 million euros in funding, and are considering the second instalment of 400 million euros necessary to complete the In Orbit Validation (IOV) phase. According to a GJU statement, "The evaluation of this joint proposal, compared to both individual offers, showed a significant reduction in the financial contribution from the public sector and an increase in the foreseen commercial revenue." The GJU will now negotiate the concession contract on the basis of this joint proposal, and hopes to sign a contract by the end of 2005.

The gain of commercial revenue constitutes a key point in negotiations, as each contributory EU member state seek the maximum number of jobs and capital investment possible. Germany contributes most to the initial Galileo program, and at the European Navigation Conference (ENC) GNSS 2005, held July 19-22 in Munich, the German Transport Ministry s head of division for telematics and new transport technology, Norbert Schuldt, made an explicit push for the Galileo Control Centre to land at the German Space Operations Centre in Oberpfaffenhofen, near Munich. Schuldt explained the virtues of another German aerospace facility, the European Space Operations Centre at Darmstadt, with its good communications with Oberpfaffenhofen, as a necessary back-up facility. However, it is expected that the French and Italian aerospace facilities also are in contention for the second if not the first position.

Paul Verhoef, the European Commission s head of unit for Galileo, has responsibility for developing a downstream market for Galileo, with opportunities for small and medium enterprises. He drew emphasised the interests from countries outside the EU, that wish to join Galileo: China, Russia, Ukraine, India, Israel, Brazil, Argentina, Mexico, and Australia. Verhoef sees a main part of his role as ".. keeping pressure on the whole system so there is no slippage on the timetable," .

Günter Stamerjohanns, CEO of Galileo Industries (GaIn), is the prime ESA contractor and represents the industry perspective. The consortium includes; Alcatel Space, Alenia Spazio, EADS Astrium GmbH and Ltd., Galileo Sistemas y Servicios, and Thales. He outlined three options: 1. An agreed-upon additional 400 million euros, that should see a full IOV contract by Q3 this year; 2. A release of only the currently available funds of 400 million euros, will result in ESA and GaIn continuing to work on the basis of an extended advanced technology program (ATP); or 3. Neither decision is reached, and this may force ESA to freeze the Galileo program.

GaIn is currently in a race with Surrey Satellite Technology Ltd. (SSTL) to complete the first of two Galileo experimental satellites, for a scheduled launch on December 8. The GaIn satellite currently undergoes testing at Alena Spazio. Overall, Stamerjohanns saw "a few drops of water in the wine glass -- we are not yet there."

Feb 2006 saw GIOVE-A, the first satellite of the Galileo project put forth by the European Union (EU) and the European Space Agency (ESA), launched on December from Baïkonur, Kazakhstan, atop a Russian Soyuz rocket. The craft successfully reached a circular orbit at an altitude of 23,258 kilometers, inclined at 56 degrees to the Equator, then deployed the satellite.

GIOVE-A (Galileo In-Orbit Validation Element) is the first of two satellites designed to trial systems critical to the successful operation of the constellation. Its threefold mission encompasses 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 characterizing the radiation environment of the orbits planned for the Galileo constellation.

The 600-kilogram satellite was designed and built by Surrey Satellite Technology Limited (SSTL) in Guildford, United Kingdom. GIOVE A carries 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 built by Alcatel Alenia Space (Italy) and SSTL (UK), one able to generate a simple Galileo signal and the other, more representative Galileo signals. These two signals will be broadcast through an L-band phased-array antenna designed to cover all of the visible Earth under the satellite. Two instruments will monitor the types of radiation to which the satellite is exposed during its two-year mission.

The satellite is under the control of SSTL s ground station. According to the company, all systems are performing well, the solar arrays are deployed, and in-orbit checkout of the satellite has begun. Once the payload is activated, the Galileo signals broadcast by GIOVE A will be carefully analyzed by several ground stations to make sure they satisfy the criteria of the ITU filings.

On January 12, the signals were transmitted for the first time using a Navigation Signal Generation Unit (NSGU) and the wide-band Navigation Antenna developed by Alcatel Alenia Space, and received by the Galileo Experimental Test Receiver (GETR) designed by Septentrio. The purpose of the GETR is to verify the acquisition, tracking and noise characteristics of all Galileo signals in the frame of the current Galileo demonstration and frequency filing activities.

The signals were received and analyzed by the Galileo receivers using the 25-meter diameter dish of the Chilbolton Observatory Facilities for Atmospheric and Radio Research, UK and the ESA Station in Redu, Belgium. The Galileo E5 and L1 channel signals were successfully decoded at the SSTL ground station using a Galileo navigation receiver.

The different modes of Galileo signals will be generated sequentially using the GIOVE-A first payload chain to perform the frequency filing activities. Once these frequency-filing activities are completed (expected by the end of January 2006), the payload commissioning will resume with the checkout of the second and third payload chains, assumed to be performed by mid-February 2006. Further measurement campaigns will then be carried out to assess the Medium Earth Orbit radiation environment, characterize the performance of on-board clocks, and perform signal-in-space experimentations.

A second demonstrator satellite, GIOVE B, built by the European consortium Galileo Industries, currently undergoes testing prior to a launch currently scheduled for April 16. The second test-bed satellite will demonstrate the new passive hydrogen maser (PHM), with a reported stability better than 1 nanosecond per day. Two PHMs will be used as primary clocks onboard the operational Galileo satellites, with two rubidium clocks serving as backups.

Subsequently, four operational satellites will be launched 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 (FOC). The four satellites are the minimum required to demonstrate precision positioning and synchronization.

On Thursday 19 January, the European Space Agency and Galileo Industries GmbH, the European company steering a consortium of more than a hundred firms, signed a E950 million contract that clears the way for the operational deployment of Galileo. The signing ceremony involved ESA s Director General Jean-Jacques Dordain and executives from EADS, Alcatel, Finmeccanica, Thales, Galileo Sistemas y Servicios, and Galileo Industries.

Following the preliminary authorization to proceed with EUR 150 million of work signed on 21 December 2004, the overall IOV phase contract can now move forward, drawing on ESA and EU funds accessible under the GalileoSat programme. The launch contracts will be negotiated during the course of 2006.

Following in-obit validation, the full deployment phase will cover the manufacture and launch of the remaining 26 satellites plus the completion of the ground segment comprising a worldwide network of stations and service centres. An agreement in early December to apportion the key centres among France (concession headquarters), the United Kingdom (operations), Germany and Italy (constellation and mission control), and Spain (backup control) resolved the final tussle between aerospace contractors in the respective countries.

EADS Astrium in turn awarded to LogicaCMG, a UK provider of software and management services to the IT and wireless telecoms market, a contract valued at more than E 6 million to develop the facility that will control the Galileo constellation. The Satellite Constellation Control Facility (SCCF) will initially control the four IOV satellites, and eventually the full 30-satellite constellation.

LogicaCMG will draw on its own staff from the UK, the Netherlands, and Germany, and on specialist suppliers Terma of Denmark and Siemens of Austria. The company will also select subcontractors from across Europe to supply the various necessary components for the complex facility in accordance with the procurement procedures laid down by ESA.

On January 12, the EU and the Republic of Korea agreed on and initialled the draft of a “Cooperation Agreement on a Civil Global Navigation Satellite System.” The EU has previously concluded cooperative agreements with China, Israel, India, Morocco, and others. Korea expects its export of satellite navigation receivers to reach $1.4 billion to $3.1 billion in 2010.

In March 2006 further company realignment news that French telecom equipment maker Alcatel was to swap its satellite division for 21.66 percent of defense electronics giant Thales , a joint statement said without any reference to EADS, the new European space giant.

The French government s stake in Thales would be reduced to 27.1 percent from 31.3 percent at present but the state would remain the principal shareholder. Alcatel currently has a 9.5 percent stake in Thales. The announcement made no mention of EADS, the European Aeronautic Defence and Space Company, which had also sought to join the space consortia. EADS had wanted to offer its satellite business Astrium to Thales in exchange for a stake of 15.0-20.0 percent. Thales, in taking over Alcatel s satellite operation, Alcatel Alenia Space, expects to increase its sales in 2006 by more than two billion euros (2.5 billion dollars) or by 20.0 percent from the figure in 2005, the statement said.

French authorities have backed the Alcatel-Thales tie-up in light of commitments from Alcatel to "ensure respect for the state s strategic interests," Thales said.

Alcatel will turn over to Thales its 67 percent holding in Alcatel Alenia Space subsidiary, with the remaining 33 percent controlled by Italy s Finmeccanica.

The new satellite venture would create a European business able to compete with US groups Loral Space, Boeing and Lockheed Martin, which account for about 45.0 percent of the global market for commercial satellites, worth 10.0 billion dollars in 2004.

The transaction now requires the backing of Alcatel s executive board as well as that of Finmeccanica. The alliance will also be submitted to Thales shareholders and personnel and to regulatory bodies.

Comparisons of GALILEO, GLONASS And NAVSTAR

Background

Global positioning systems (GPS) have dramatically impacted on a variety of commercial industries and operations. These systems are providing high accuracy positioning and navigational functionality in the transportation, natural resources, oil and gas, emergency, agricultural and urban planning sectors amongst others. The Russian Federation GLONASS and the American NAVSTAR systems have been providing GPS services for almost two decades. A third GPS system, the Galileo GPS system would be owned and operated by Europeans and was recently supported by the European Parliament. Each of these systems is suitable for use by positioning professionals and collectively could result in major benefits, design of new equipment and new applications that will affect all users.

History

The GLONASS satellite system and NAVSTAR systems require a minimum of 24 satellites to operate. The NAVSTAR system operates in 6 orbital planes while GLONASS uses 3 orbital planes. Initial coverage was limited and not fully operational until the mid 1990 s, though several users were routinely using them before that time.

With the fall of the Berlin Wall November 1989, allowed the use of dual GPS receivers with both GLONASS and NAVSTAR satellites. GNSS thus had a potential of almost 50 satellites and allowed for integrity checking between satellite systems, where errors between them could be processed and higher solutions obtained – particularly for navigational and transportation purposes. This would however require special GPS receivers and software termed GNSS” receivers that could track both systems, acquiring signals from each and processing them together due to the fact each operated independently and were based upon differing technical design. However the GLONASS system began to deteriorate due to lack funding. Till the Russian Federation Declarative of 1999 stated its purpose to provide and promote, “strengthening confidence and openness in international affairs, upkeep international stability and widen scientific and technical relations between states”. About the same the U.S. government was reviewing NAVSTAR in a study before the Senate Armed Services Committee said: "It is clear that GPS offers the potential to revolutionize the movement of goods and people the world over. Civil and commercial exploitation of GPS could soon dwarf that of the Department of Defense and lead to large productivity gains and increased safety in all transportation sectors." The U.S. joint program office for NAVSTAR sums their goals as follows: NAVSTAR GPS Satellite Courtesy U.S. Joint Program Office

• Mission Acquire and sustain survivable, effective, and affordable Global Positioning Services for our customers.

• Vision We are the centre of excellence for space-based navigation.

• Motto Any Time, Any Place, Right Time, Right Place

Thus both NAVSTAR and GLONASS have become more directed toward civilian applications making that increasingly possible. Originally NAVSTAR had accuracy of ± 100 m @ 95% in the horizontal plane and ±186 m @ 95% in the vertical plane (x-coordinate) for civilian use. That was significantly improved with the abolishment of selective availability (SA) or time dithering of GPS signals that resulting in higher levels of errors. These errors are now 36 m @ 95% horizontal and 77 m @ 95% vertical respectively, though most users achieve much better accuracy often. The GALILEO system aims to provide similar or better levels of accuracy. Within the last few months 3 new GLONASS satellites have been launched and it would appear that yet another attempt to complete that constellation is underway. Thus, at present NAVSTAR is fully operating, GLONASS is launching new satellites and GALILEO remains to be fully developed. This creates interesting issues for the U.S., Russian Federation and the 15 members of the EU participating in GALILEO and the supporting European Space Agency.

GALILEO

The GALILEO GPS system while appearing to be controversial is being proposed for technical reasons, economic and sovereignty reasons which in the long run can impact European scientists and civilian users and those interested in high quality positioning and navigation for GIS worldwide. Technically, GALILEO is designed to integrate both NAVSTAR and GLONASS to become a truly GNSS solution – or operate independently. There would be 30 satellites in the GALILEO constellation. In total combined, almost 80 satellites combining the 3 GPS systems would potentially be available to be tracked using a combined GNSS receiver. Secondly, because the angle of inclination for satellites with respect to the equator will be higher, better coverage of northern European areas will be possible – something which GPS does not do as well as needed at the moment. Thirdly, GALILEO would allow European providers of spatial services closer control over positioning services and be less affected by military needs of NAVSTAR, which at times results in the movement of satellites for military purposes. This system is being proposed by the 15 EU member states as well as the European Space Agency, which is a consortium of numerous companies involved in geo-science and scientific study for the European region. Perhaps one of the strongest reasons for envisioning GALILEO is that it becomes truly an international platform, designed to deal with interoperability issues arising from integration with NAVSTAR and GLONASS and is operated from a civilian standpoint – not a military one. Thought the European Parliament has indicated that military peacekeeping should be part of the mandate for GALILEO.

In December 2001, several members of the EU and the European Space Agency advocated that GALILEO is an imperative for Europe and must proceed with final approval no later than March 2002. This was later articulated in the context of European sovereignty by former Swedish Prime Minister Carl Bildt, “ If Europe really wishes to be taken seriously as a partner by the U.S. while ensuring it has access to capabilities critical for its economic development, it must demonstrate it has the will and means to develop a presence in space”. Economically, some reports indicate that GALILEO could generate as much as 190B$ in goods and services, new products and technologies over 10 years while at the same time providing many jobs in an expanding European space program. Debates continue but the European Parliament approved the GALILEO system in February 2002 but indicated a reduced direct involvement with industry for its operation. But for those of us involved in spatial sciences and using GPS to build and provide GIS solutions, there could potentially be many benefits for having 3 systems.

In fact, there are some GNSS receivers on the market today. At that time users were expecting higher levels of accuracy until the sudden decline of the GLONASS system. With the advent of GALILEO it might very well be that users will once again return with high expectations of a dual GPS receiver. NAVSTAR has operated continuously and there have been many products and services enter the market place using that system, which have met users needs while enhancing their capabilities. This existing infrastructure has grown to become a multi-billion industry with forecasts in the neighborhood of anywhere from 7-12 $B by 2008 – and that is only for GPS and related products using the NAVSTAR specification and system. GALILEO GPS Satellite Courtesy: European Space Agency

Users need to carefully plan and check interoperability between hardware, software and training/education needs. Each of these, are determined by the current continuous and useful presence of NAVSTAR. Issues that address the unique operating specifications of all three systems if they are to be integrated successfully will need to be addressed. The abolishment of selective availability in the NAVSTAR system has resulted in higher accuracies, which have allowed many first time users of GPS products to enter the market and achieve quality results and success without having to resort to differential correction. Though, higher accuracy GPS applications still require differential GPS processing to consistently obtain sub-meter performance since atmospheric effects, multi-path and noise remain as error sources.

If GNSS is developed to the extent predicted and the level of interoperability is achieved then this could conceivably result in a new thrust of development involving GPS equipment. Increased training in interoperable systems may be just around the corner, though it can be anticipated that much of this interoperability will be designed into software and hardware and operate in a hidden fashion. Data will be collected, processed and downloaded readily. Datum and geoids will be calculated on the fly and the systems will work smoothly without the user even knowing all of these processes are being performed. Even data tables will be seamlessly created. How would differential corrections be applied? Could it be that any combination of the three would be possible?

The next question becomes, who are likely to be GNSS users? Without a doubt many European countries and users will embrace GNSS since it is supported by the member states through their Parliament. This could also result in many more users in higher latitudes for which the system is designed if GALILEO is incorporated. Along with NAVSTAR, applications will be augmented, particularly for regions where satellite visibility in valleys and inner cities are involved resulting in more real-time applications. NAVSTAR will continue to dominate the GPS scene due to its already existing and installed infrastructure that supports the system in hardware, software and technical know how. But more importantly is the issue of interoperability and capitalizing upon all three systems. Static GPS sampling involves occupying as position for a longer time period. Using GNSS, static samples would likely have higher levels of accuracy and may even require shorter occupation times thereby increasing the amount of work a GPS crew can accomplish in a day the larger numbers of satellites. Is all this potential increase in GPS accuracy going to result in improved maps and analysis capability? Yes and no. NAVSTAR is the only fully operating system at the moment and major improvements in the system are planned by the U.S. Department of Defense. It is still too early to tell if the recent launching of three GLONASS satellites is a trend, which will continue until a full complement of GPS satellites is available. GALILEO itself is not planned to be fully operational until 2008. Most IT sections in organizations turnover or upgrade software about every 2-3 years or less and GPS equipment is updated using a similar schedule. For the short term, it is too early to be making the big economic decisions about moving into the GNSS market in a large way. However, in the long term we will be hearing more about GNSS, and the benefits as new products and technologies evolve in the marketplace. It is not too early to begin planning though and learning about these systems.

Recent launches of new satellites in the GLONASS GPS system may lead to the establishment of a second fully functional GPS system in the near future. Coupled with the already existing U.S. NAVSTAR system, GNSS applications may grow in the future. A third European based satellite system called GALILEO has been approved in principle but is not expected to be fully operational before 2008. Designed with interoperability in mind, GALILEO in addition to the others could result in GPS users having access to almost 75 satellites for highly accurate navigation and positioning. These developments have many potential advantages for not only the data collection aspects for GPS users, but also for the development of new applications worldwide.

In the meantime, the ESA offer an augmentation of the NAVSTAR GPS satellites through a network of European differential broadcast satellites. The system is called EGNOS or European Geostationary Navigation Overlay Service. It has marked formal completion of its technical qualification and acceptance by the European Space Agency (ESA) on June 16 2005. Testing of the system and effective operational use of the signal by some users has occurred since late 2004.

Three geostationary satellites above Europe transmit a GPS-like signal delivering corrections that improve positioning accuracy to the 1-2 meter level, while also providing service guarantee and integrity information.

The formal review, called the Operational Readiness Review (ORR), marked the completion of more than eight years of intensive work by ESA and an industrial consortium led by Alcatel Space with more than 40 European companies.

More than 60 international experts from ESA, as well as Eurocontrol, the Galileo Joint Undertaking, and the EGNOS Operator and Infrastructure Group gathered in Toulouse during May 2005 for the comprehensive review. They focused on functional qualification and operability of the system, its stability in its real environment, performance, and compliance with the requirements and safety and product assurance issues, including software qualification.

EGNOS deployment, nearly complete, consists of 30 ranging and integrity monitoring stations (RIMS) in 21 countries; four mission control centres (MCCs) in Spain, Italy, UK and Germany; six navigation land earth Stations (NLESs) in Italy, France, Spain and the UK, and support facilities in Spain and France.

EGNOS initial operations can now start through a contract with the European Satellite Service Provider (ESSP). By early 2006, when operational stability is expected to be reached, the EGNOS open service will be declared formally available to the general public over Europe for non safety-of-life applications, free of direct charges. Currently, the general public can receive the EGNOS signal on a test basis.

Designed as a stepping stone towards the Galileo system, Europe s GNSS took two steps forward, one step back in August 2005. The European Geostationary Navigation Overlay Service (EGNOS) began its Initial Operation Phase (IOV), and one of two Galileo satellites currently under development, GSTB-V2/A, arrived at the European Space Agency s (ESA s) Research and Technology Centre to undergo testing.

Meanwhile, Germany and two other European governments declined again in July as they did in June to bring forward their shares of funding in ESA s E400 million project financing. Germany has linked its contribution to a demand of special privileges in the Galileo Concession Scheme, yet to be awarded. ESA perceives this as somewhat unfair, as the GJU, not ESA, is responsible for negotiations with the potential Galileo concessionaire consortium.

The other two countries are likely to settle their differences with ESA and unblock their agreed contributions to the IOV Phase fairly soon. Officials said the funding impasse "will have several consequences" that could include a slowing down of the Galileo project.

GLONASS

On December 25, a Proton-K carrier rocket launched from the Baïkonur space centre in Kazakhstan delivered three GLONASS satellites into designed orbit, joining 14 operational satellites currently in space. The next day, Russian President Vladimir Putin directed that the GLONASS global navigation satellite system become fully operational again, that is, with 24 operational satellites, earlier than the currently targeted 2008 date.