ISO 18197:2015 defines the requirements for the wide area centimetre class positioning system by broadcasting augmentation data through satellites as follows.
- Centimetre class positioning
According to the progress of requirements for positioning services such as automatic farming, mapping and others, centimetre class positioning is very useful.
- Wide area positioning
It is quite effective to broadcast augmentation data through satellites for users over wide area such as a square, more than 1,000 km each side, anytime and anywhere. Even if this area is short of data network, additional ground network facilities are not needed. In addition, as ranging signal and augmentation data can be received from satellite broadcasting at the same time, it is unnecessary for user terminals to receive the signal such as transmitted by ground network.
- Real-time property
The user terminals need to resolve the ambiguity in real-time, using augmentation data broadcast from satellites or other means, for the realization of centimetre class positioning. On the other hand, the provider sides have to broadcast augmentation data such that the terminal sides are able to resolve the ambiguity in real-time.