Europe’s new satellite navigation system

• In development
• First test satellite operating successfully since late 2005
• Second test satellite launched April 2008
• Full operational capability planned for 2013

Featuring 30 satellites and a ground support network, Galileo is being designed to offer users satellite navigation with an accuracy of less than one metre. Unlike current navigation systems, such as GPS, Galileo will provide a guaranteed service under all but the most extreme circumstances. This will make it suitable for applications where safety is critical. For example, it could be used to land aircraft.

When Galileo reaches full operational capability its satellites will provide coverage of even the most remote parts of the globe. Up until now, coverage of latitudes in the Arctic has been patchy at best. With a larger number of satellites than GPS, Galileo will also give greater reliability. If one satellite malfunctions, the service will be able to continue unaffected.

The first Galileo satellite, GIOVE-A, was launched in December 2005. Built by UK company Surrey Satellite Technology Limited (SSTL), it continues to perform well. The second test satellite, GIOVE-B, was launched in April 2008. Once the technology on board GIOVE-B is proven, the first four operational satellites will be launched. Industry estimates suggest that by 2015, Galileo will be generating €20 billion worth of economic benefits every year.

We are already seeing the advantages of satellite navigation technology. The European EGNOS system is proving the value of more accurate satellite navigation.

Mission facts

• Because of its reliability and accuracy, Galileo has tremendous potential for improving air traffic control. It will allow planes to reduce their reliance on ground-based beacons or radio signals and will help improve safety in poor weather conditions.
  
  
• More and more drivers are expected to adopt satellite navigation. Freight companies will be able to use Galileo to track containers more closely. This will help them to combat theft and fraud.
  
  
• Satellite technology is also being developed to help older and vulnerable people. If they were to suffer a medical crisis, an inbuilt satellite navigation system receiver in conjunction with mobile phone technology could alert emergency services to their location.
  
  
• A trial of a satellite system developed by UK company SciSys, has shown that railway signals controlling the movement of trains could be replaced. During an experiment, the position of a train was monitored and messages sent to the driver about whether to proceed, slow down or stop.

Technology

Satellite navigation systems don’t actually track your position, you find out where you are by using them.

The spacecraft, in a highly accurate orbit, transmit signals toward the Earth. The receiver measures the time it’s taken for those signals to arrive. It then uses the information to work out the distance between you and the orbiting spacecraft.

The GPS system, for example, uses 26 satellites. By taking signals from several satellites, the computer within the receiver can use trigonometry to work out the users’ position to an accuracy of a few metres.

Some navigation systems can overlay satellite information onto a map display. The maps themselves can be updated either via radio or the Internet.

The primary objective of the first Galileo satellite, GIOVE-A was to secure the frequencies allocated to Galileo by the International Telecommunications Union, a United Nations agency.

GIOVE-A, is equipped with two atomic clocks. These have proved to be extremely accurate. The spacecraft also has two signal generators to provide Galileo navigation signals as well as instruments on board to monitor the radiation in the harsh space environment.

GIOVE-B carries the most accurate atomic clock ever flown in space. The satellite will also be used to test the transmission system for navigation signals.

UK involvement

The UK is involved at every level in developing the next generation of satellite navigation technologies.

GIOVE-A was built, and is operated by, Surrey Satellite Technology Limited (SSTL).

The payload for GIOVE-B was developed by Astrium Limited in the UK. A Portsmouth-based team tested and integrated the equipment onboard the satellite.

The UK, through BNSC, is also actively encouraging the development of new technologies to exploit the potential of satellite navigation.

The Government-funded Location and Timing Knowledge Transfer Network is fostering efforts to develop new applications and services. The network involves collaboration between academics, industry and government. It is helping to create new markets and provide support to business.

BNSC supports the UK Satellite Navigation Challenge, co-ordinated in the UK by the Hertfordshire Business Incubation Centre. This annual competition (which forms part of a larger European competition) is aimed at encouraging new applications of satellite navigation technology.