Emma Kelly/LONDON
Europe is on course to make "a historical decision" on the second stage of its satellite navigation programme in the first half of 1999, says Neil Kinnock, European Commission (EC) transport commissioner.
Since Kinnock presented the EC's satellite navigation strategy at the beginning of this year, the Commission has been working hard to define Europe's involvement in the development of a second generation global navigation satellite system (GNSS-2).
The EC had defined three options for Europe to consider in its long term GNSS plans: joint development of the GNSS-2 by all the major world interests; development by the European Union, together with one or more international partners; and independent development of Europe's own system on a regional or global basis.
"Following our international contacts, especially with the USA and Russia, the range of realistic options has become more refined," Kinnock told the GNSS '98 symposium in Toulouse, France, in October. Discussions with the USA have confirmed that there is no possibility of joint ownership and control of the global positioning system (GPS) because of its continuing military role, he says.
The US strategy, however, does include "-a genuine willingness to achieve co-operation", says Kinnock. The Russians, meanwhile, are keen to co-operate with Europe on a second-generation GNSS and have even agreed in principle to Europe sharing control of its Glonass navigation satellite system. While Europe is formulating its plans for the second stage of its GNSS approach, development of Europe's GNSS-1 - the European Geostationary Navigation Overlay System (EGNOS) - is well under way.
The EGNOS, which is being developed by the EC, Eurocontrol and the European Space Agency (ESA), collectively known as the European Tripartite Group (ETG), will rely on the GPS/Glonass augmenting these satellite systems' integrity with additional ground and space based infrastructure. The EGNOS signals will be broadcast via two Inmarsat-3 satellites and the Artemis spacecraft.
EGNOS advanced operational capability is scheduled for early 2002, while full operational capability is planned for 2005. Cost-benefit studies for the system are advanced and a contract for EGNOS development is expected to be awarded to an Alcatel-led European consortium by early 1999.
MULTIMODAL SYSTEM
The EGNOS is designed to be multimodal, with aeronautical, maritime and land users set to benefit. Aviation users, in particular, will benefit greatly from the EGNOS, claims the EC. "The EGNOS will provide a precision approach capability at all airports throughout Europe and the greater operational reliability for the airlines will obviously bring benefits for the whole aviation community," says Kinnock.
There is just one problem, however. Europe's aviation users do not want the EGNOS and most definitely do not want to pay for it. The region's major airlines, represented by the Association of European Airlines (AEA), first raised their EGNOS concerns over a year ago and have not changed their views since then, despite the efforts of EGNOS supporters.
The association wants a tailored, civil-owned system which cannot be switched off for political or military reasons and which, instead of needing augmentation, needs only accuracy and integrity monitoring. The AEA, in other words, wants to go straight to the GNSS-2, a system which is still only conceptual.
In October 1997, the AEA first wrote to the ETG members and called on them to stop development of the EGNOS for aviation users and instead to concentrate all efforts on the GNSS-2. The association concluded that the EGNOS will provide "no tangible benefits to airlines". Since then, the AEA has presented its case to the European Parliament and Europe's Council of Transport Ministers in a bid to stop the development of EGNOS for aviation users.
Although the AEA is not alone in its opposition to the system, it has been by far the most active in its anti-EGNOS campaign. The International Air Transport Association (IATA), the International Council of Aircraft Owner and Pilot Associations, the European Business Aviation Association, the International Air Carrier Association and the European Regions Airline Association have all expressed their concerns over the EGNOS to Europe's transport ministers.
All of these associations have supported the AEA's views that the EGNOS will not provide any tangible benefits to the aviation community, that their respective members would oppose paying for the EGNOS and that Europe should stop EGNOS development and proceed straight to the GNSS-2.
IATA director of infrastructure Phillip Hogge has charged that the decision to develop the EGNOS was a political one. It was launched, he insists, without industry consultation or any proposal for transition from ground based to space based navigation systems and with no costing transparency.
Europe's airlines have nothing against satellite navigation - in fact they are all for it. "Airlines require navigation aids which are both reliable and cost effective. The AEA sees potential benefits in the next generation of satellite navigation systems called the GNSS-2. We expect the GNSS-2 to reduce costs, improve capacity, improve reliability and to make conventional navigation systems obsolete," the association told the ETG a year ago. In addition, the AEA has pointed to local area augmentation systems (LAAS) as capable of providing far greater benefits.
That was over a year ago and the airlines' views have not changed. From an airspace user's point of view, the EGNOS is "a wrong business investment", Vincent de Vroey, assistant technical affairs director at the AEA, told the Flight International/Air Navigation International air navigation conference in September.
The EGNOS does not meet aeronautical user requirements, says de Vroey, pointing to airlines' objectives of increased safety, reduced costs, increased capacity and reduced delays/increased schedule reliability. "If an older technology is more cost effective, airlines will prefer to stay with this rather than move to a more sophisticated system, unless justified by a significant safety improvement," he says.
A well designed GNSS would enable a reduction in accident rates, especially outside Europe, but the deployment of LAAS ground stations at dedicated non-European airports which do not have adequate approach systems could result in a significant safety improvement, says de Vroey.
Cost reduction is a priority for airlines in Europe. The inefficiencies in the European air traffic management system are costing airlines up to Ecu2.5 billion ($2.9 billion) a year, claims de Vroey. Some Ecu600 million is down to route inefficiency, Ecu1,200 million through capacity shortage and Ecu600 million in cost inefficiency at air traffic control centres.
En route charges account for 5.4% of the costs of the AEA airlines' operations on European routes and, while passenger yields are decreasing, en route charges have stayed constant. "It is consequently a matter of significantly decreasing European route charges. Any GNSS that does not meet the objective of significantly decreasing route charges is hence, de facto, a wrong business investment," says de Vroey.
The AEA fears that the EGNOS could have the opposite effect, because of the investment in the system by air traffic service (ATS) providers. The five ATS providers which are members of the EGNOS Operations Group - Germany's DFS, the UK's NATS, Spain's AENA, France's DGAC and Italy's ENAV - have agreed to commit Ecu100 million to the first phase of the system.
The association has recently written to the ATS providers to determine how those costs have been, or will be, passed on to the airlines. Replies, concedes the AEA, are not expected for a while yet.
DEVELOPMENT COSTS
The "intermediate" GNSS development costs should not be passed on to the airlines, ATS service providers have stated. The EGNOS is officially recognised as an intermediate measure en route to the GNSS-2.
Despite assurances that the EGNOS cost-recovery system will be fair to all users of the system, and not just to aviation users, the AEA is concerned that the money committed for the EGNOS by the ATS providers will be charged directly to aviation users, regardless of whether they use the system or not. There is now an "urgent need for action" to ensure that the Ecu100 million will not be recovered via the en route airspace user charges, says the association.
The EGNOS is also a bad investment, says the AEA, as, for a variety of reasons, it will not provide tangible operational benefits. The EC and EGNOS industry supporters have argued that the foreign military control of the GPS could make complete dependence on the system potentially dangerous for European users.
The AEA has sympathy for this argument, but rejects it as a reason to develop the EGNOS, on the grounds that the system will not function without the GPS. "By investing a considerable amount of tax money in an overlay system to the GPS, Europe is increasing its dependency on the GPS," suggests de Vroey.
To solve this "institutional deadlock" over the use of the GPS in Europe, the association sees no other option than to work on a civil-controlled GNSS-2. "Our support for work on GNSS-2, however, should not be seen as a blank cheque pro-GNSS-2. Any GNSS-2 should obviously be interoperable with the GPS, based on end user requirements, and its implementation should be based on a transparent cost-benefit analysis and a fair allocation of costs among the different user groups. The GNSS-2 should be funded by European public resources as a general utility system, in the same way that the GPS has been funded by US tax resources," de Vroey suggests.
The EC and EGNOS advocates have also argued that the system is an essential pre-condition for the GNSS-2. The AEA disagrees, arguing that the GNSS-2 will be based on different satellites and a different system. "No technical infrastructure of the EGNOS will be necessary for the GNSS-2, although most GNSS-2 proposals have been forced to make use of the EGNOS infrastructure," says de Vroey.
Speaking at Global Navcom, Eurocontrol director general Yves Lambert, backing Kinnock and the EGNOS, said: "We cannot remain idle and then try to scale the cliff face of the GNSS-2. Indeed, no-one knows what the GNSS-2 will be. We have to complete stage one first." He continued: "Without the valuable experience we in Europe are gaining through the EGNOS, we would, in all likelihood, simply not have enough knowledge to create a viable, cost effective system that meets all our needs - both technical and legal - for aviation navigation by satellite."
Gaining satellite navigation experience for the GNSS-2 through the EGNOS is a valuable reason for supporting the overlay system, concedes the AEA, but it is not one related to user requirements and therefore cannot be the basis for user support.
The EGNOS will not provide any tangible operational benefits for the "high end equipped" commercial airlines, they argue. The functions of the EGNOS can effectively be per- formed by on-board augmentation systems together with conventional navigation aids, they say. The system will provide at best Category I precision approach capability in the core area of Europe, but the continent has a long term requirement for Cat II/III capability. In the short term, instrument landing systems and microwave landing systems are required for this, while the LAAS will be required in the longer term, suggests the association.
EGNOS supporters also claim that the system will bring advantages outside Europe to areas such as Africa which are now lacking in navigational aids.
"Although AEA members acknowledge those facts, they are not convincing arguments to support the EGNOS. Since the EGNOS is a European system, the majority, if not all, of its costs would be recovered via the European Route Charges System. It suffices consequently to mention that it cannot be the task of European operators to finance the necessary improvement of inadequate infrastructure in other parts of the world," says de Vroey.
An argument raised by EGNOS supporters is that Europe should develop the system because the USA will have the wide area augmentation system (WAAS). "The AEA believes that Europe should learn from US mistakes. The WAAS is already far more deployed than the EGNOS and continuously under criticism because of its high costs and limited benefits," says de Vroey. Furthermore, the EGNOS should not be developed just to secure Europe's position in the future multi-billion dollar GNSS market, the AEA says. The EC has consistently stated that Europe cannot afford to be left out of the GNSS race.
"The [GNSS] market is developing so fast that we need to develop now a strategy for the future. In this technology, late in will mean that Europe is locked out of a market estimated to be worth $50 billion by 2005," Kinnock said earlier this year.
The AEA disagrees, however, saying: "It is completely unacceptable to pursue a system which is benefiting one part of the European industry - for example the European space technology industry - and then to pass on the costs to another part of the European industry - the airlines - deriving no tangible benefit."
The AEA argues. "If a civil-controlled GNSS-2 system would be directly pursued by Europe, the European industry would have the opportunity to be there before their US competitors."
Any GNSS-2 would have to be designed on end user requirements - increased safety, reduced costs, increased capacity and reduced delays, says de Vroey. In addition to calling for further work on the GNSS-2, Europe's major airlines see major benefits in the LAAS, according to the AEA.
STANDARD BEARER
The AEA believes that the LAAS has the potential to become the new standard landing aid for Cat I to III operations, has applications in the surface movement guidance area, could be used for precision departures and is potentially cheaper than existing navigation aids because of its multiple runway/ airfield coverage.
Not enough research is being conducted to move LAAS developments in Europe forward as "-the vast majority of tax resources are being drained into the EGNOS", suggests de Vroey.
From the recent statements of leaders such as Kinnock, Europe appears certain about why it must play a major role in the GNSS. It is a measure of the lack of policy transparency, however, that no-one - especially the users - appears to know what the funding policy is.
Proving Capability
David Learmount/KEFLAVIK
Flight trials at Keflavik, Iceland, in October, supervised by the country's Civil Aviation Administration (ICAA), have made satellite navigation augmentation systems more credible to the user community.
Tests have been run this year, using prototypes of the US Federal Aviation Administration's WAAS and Europe's EGNOS, and they have been proved individually to be capable of supporting precision approaches to Cat I criteria - in accuracy, if not integrity. Now, interoperability between the two has been tested and found to be within a few software tweaks of reality.
Interoperability between the WAAS and the EGNOS is "no longer an issue", says Ken Ashton, deputy engineering manager navigation services for the UK National Air Traffic Services (NATS), after a series of successful precision approaches at Keflavik, using GPS signals augmented by the US and European prototype systems. At the Keflavik trials, co-ordinated by the ICAA, the FAA fielded its Boeing 727-100 test platform, and NATS tests were done by the UK Defence Evaluation and Research Agency's (DERA) BAC One-Eleven "flying laboratory". Each was equipped to receive augmented signals from the FAA's National Satellite Test Bed (NSTB), the WAAS prototype and NATS' Northern European Satellite Testbed (NESTBed), a "pseudo-EGNOS".
NESTBed, a NATS/Racal project, consists of a network of ground stations and a navigation transponder mounted on the Inmarsat-3 spare satellite in geosynchronous orbit over the equator at about 25° East - the NSTB uses the Inmarsat-3 Atlantic Ocean Region West satellite, and both are in view over Iceland. The fact that Iceland is at the north-western edge of both NESTBed and EGNOS coverage made it suitable for checking out the system's capability at its limits. Also, the ICAA has been working with its FAA partner on the WAAS for several years, and a ground reference station, cable linked to the FAA network, is in Iceland, making it an integral part of the NSTB.
The FAA 727, equipped with two separate receivers and processors, was able to receive and compare signal corrections from both augmentation systems simultaneously. The test team says that differences never exceeded 5m (16ft) in azimuth or elevation and were normally in the realm of 0-3m. This compared with the first NESTBed demonstrations at Royal Air Force Boscombe Down in September, which showed variations between the EGNOS and ILS of less than 6m vertically and 3m horizontally.
At the Iceland trials, the NATS team reported similar comparison results from its single system, which could switch between NSTB and NESTBed augmentation. NATS says that the two signals will soon be accepted simultaneously on the one receiver, but there remain "a few unforeseen software glitches" to sort out.
Near identical performance from the two systems may be reassuring, but provision of a true precision runway approach is the crucial issue. In both aircraft, the approach guidance was delivered to the pilots as an ILS-type display, and the aircraft were flown manually. The guidance delivered invariably put each aircraft perfectly on the runway extended centreline and glidepath, the teams say.
Although the runway approach tests were technically to Cat I decision heights, the FAA 727 pilot flew the aircraft, in landing configuration, down to something closer to Cat II before levelling, flying along the runway centreline and finally going around. The position readouts on the test equipment showed perfect lateral precision throughout.
International Civil Aviation Organisation standards (SARPS) for augmentation systems are scheduled to be completed by April 1999, and the Icelandic tests were designed to prove that the current SARPS have successfully standardised the software algorithms and the signals in space, so that any GNSS receiver is capable of functioning with guidance from any space-based augmentation system signal.
The entire terrestrial network for the WAAS, plus its two satellites, is now in position and will be on line in mid-1999 to provide non-precision GPS approaches. The EGNOS' three geostationary satellites will be in orbit by the end of 1999 and the system will become operational in 2002, providing augmentation for both GPS and Glonass signals, as well as a standalone GNSS service.
Source: Flight International