Julian Moxon/PARIS
A Eurocontrol system enabling European airspace users to take full advantage of the US global-positioning system (GPS) for sole-means navigation may be cancelled if the USA fails to go ahead with its own, equivalent, programme.
The European geostationary navigation overlay system (EGNOS) is meant to give Europe an independent means of using GPS as a primary means of navigation and as a landing aid for approaches up to Category 1 standards. It is similar to the USA's Wide Area Augmentation System (WAAS), which is now under intense scrutiny by the US Congress as the programme suffers severe budget overruns and technical problems. The US and European airline industries have already questioned the need for the two systems, demanding that more emphasis be placed on developing a second generation global navigation satellite system (GNSS-2).
A Eurocontrol source says the agency is playing a "watch and wait" game while the USA decides what to do with the WAAS, but adds that it is "not worried" by the prospect of cancellation, since Europe has an intense ground-based system of navigation aids which could continue in service until the GNSS-2 is established.
The source also reveals that Eurocontrol "is thinking very seriously" about Glonass [the Russian equivalent to GPS] coupled with GPS and EGNOS as a "step towards" GNSS-2. He adds that while the EGNOS is not seen as essential for providing navigation in Europe, it is "extremely useful" for building European technical, industrial and operational competence in satellite navigation,
The US General Accounting Office (GAO) says that the WAAS programme could see cost overruns approaching $166 million. While it agrees the system may provide major cost benefits to the airline industry, the GAO questions its ability to provide precision to Cat1 standards, as well as its integrity, availability and the danger of electromagnetic interference.
Full operational capability of EGNOS is due in 2002, when, according to Eurocontrol, it will have "sufficient redundancy to be considered as a standalone navigation system for the most demanding applications".
The system is being developed mainly with European Space Agency and European Union funding. Eurocontrol rejects accusations that it will not be fully compatible with the WAAS and the Japanese MTSAT systems ."We are working at a very high level to ensure total interoperability," says the agency.
Source: Flight International
