GNSS correction services for ITS applications a performance analysis of EGNOS and IGS

Accurate positioning is the key technology for many safety and comfort related ITS and ADAS applications. In order to determine the absolute position, GPS is still the first choice for application designers. Within the European research project GAIN for example, an active green driving application is developed that highly relies on GPS/Galileo positioning. In order to get the best possible position estimation from low-cost GNSS receivers, all error sources must be taken into account. A large contribution of the error budged of a measurement from a single satellite is introduced when the signal passes the ionosphere. Depending on the condition of the ionosphere, the resulting error in the position solution can easily increase to several meters. There are several services and static models that provide correction information to determine the ionospheric error. In this paper the performance of several common ionospheric correction services is compared with a special focus on ITS and ADAS applications. The most common models are provided by the European Geostationary Overlay System EGNOS and by the International GNSS Service IGS. Next to the reached position accuracy, the services will be compared in terms of integrity which is a crucial point for safety relevant surface transportation systems.