Satellite Navigation Systems
Global Navigation Satellite Systems (GNSS) and their augmentation systems together enable countless uses and services in contexts making use of location, navigation and very accurate time data.
Photo: ©European Agency for the Space Programme (EUSPA)
All satellite navigation systems share the same operating principle: the system’s satellites transmit radio signals and the user’s satellite navigation receiver then uses the structure and message content of those signals to compute the user’s location and the accurate time. There are currently four GNSSs that are globally available and openly accessible by all:
In addition India (IRNSS) and Japan (QZSS) are developing their own regionally operational satellite navigation systems. The opportunity to use multiple GNSSs at the same time increases the number of available satellites many times over compared with a situation where only one system is used. This improves the accuracy of deter-mining the location and time, particularly in more challenging conditions such as street canyons and forests featuring obstacles to satellite signal reception.
Use of GNSS systems
GNSSs are part of our everyday life, even if we are not always aware of their existence. Accurate location and time data is an important factor not only in many consumer applications but also in many key functions of society.
Augmentation systems for GNSSs
Systems to verify and specify GNSS location data have been implemented using different techniques. They can be used for verifying the correctness of location data in safety-critical areas, such as aviation or applications requiring very accurate location data.