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What is satellite navigation?

 

Satellite navigation represents a quantum leap in navigation. Instrument navigation based on radio beacons was first developed back in the 1930s. Since then it has developed steadily to the present day, taking into account the technology available. Over the years a globally valid standard has evolved which, thanks to its precision, permits landings even under minimal visibility, relying on a combination of ground-based navigation equipment such as instrument landing systems (ILS), on-board equipment, the procedures and training of the pilots and air traffic controllers and a dovetailed system.

 

The Global Positioning System (GPS) has been available since the 1980s and today it is generally accessible and available. In order to be able to use this technology for primary navigation in the air the following requirements for accuracy and reliability in position determination and in navigation and for the integrity and availability of the satellite signals have to be taken into account. Trials that provide insights into how GPS would functions in this context are required to test prototypes and applications and gain some preliminary operational experience before a procedure can be published and applied. Standards take a long time to be developed as the new technology has to be integrated into every aspect of the existing system.
chips, the Switzerland-wide implementation programme for SESAR related activities and objectives, which involves all relevant companies, was launched in 2008 with the aim of further developing the Swiss aviation system with innovations and new technologies. In this connection chipsconstitutes the national coordination platform with all the important organisations and associations.

The programme came into being with satellite navigation as the first technology. Experience to date can also be transferred to the agreed innovation topics of “IFR in airspace class Golf without air-traffic control services», Remote TWR and «Surveillance by multilateration”.

 

Satellite navigation offers considerable potential:

 

  1. With curved flight, a predefined flight path is defined in such a way that, compared with conventional navigation technology, there is distinctly less variance. This results in channelling of the noise and a reduction in the number of people affected by noise.
  2. Because curved flight is possible, on the one hand obstacles can be flown around. In hilly or mountainous terrain, flatter descent profiles become possible as a result, making it a lot easier to get to an airport.
  3. On the other hand, curved flight makes shorter flight paths possible, resulting in reduced fuel consumption and gaseous emissions. Flight duration is also reduced.
  4. Instrument flight procedures can be defined for any airstrip without the  need for investment in conventional navigation equipment.
  5. The navigation precision means that in the long-term it should be possible to adapt the criteria for structuring airspace so that less controlled airspace is needed.

 

The major challenge with satellite navigation is how to integrate the new element into the existing aviation system without increasing complexity. At the present moment the biggest challenge is the low percentage of aircraft fitted with the necessary equipment. Only when a clear majority of aircraft are satellite navigation capable can the potential be fully utilised.
Another challenge lies in the fact that in Switzerland satellite-supported flight procedures might encroach into places and areas that today are claimed by other airspace users; this presupposes that everyone involved is willing to compromise.

 

A third challenge is the environmental impact, especially the noise: new flight procedures will mean a redistribution of the traffic load. Whereas the procedures used up to now may be used less and the noise impact lessened, the latter will shift to new areas that have not previously been overflown. The reduction that benefits some places is at the expense of other places.
At the end of the day it is a matter of weighing up the conflicting interests of politics/noise, safety and efficiency/capacity.