EN 16803-1 addresses the final stage of the performance management approach, i.e. the assessment of the whole Road ITS system performance equipped with a given GBPT, using the Sensitivity analysis method. EN 16803-1 addresses the assessment of GBPT performance, since it identifies and defines the positioning performance features and metrics to be used in the definition of the GBPT performance requirements. This EN gives definitions of the various items to be considered when specifying an Operational scenario and provides a method to compare finely two environments with respect to their effects on GNSS positioning performance. This EN gives definition of the most important terms used all along the document and describes the architecture of a Road ITS system based on GNSS as it is intended in this standard. This EN does not address: - the performance metrics to be used to define the Road ITS system performance requirements, highly depending on the use case and the will of the owner of the system; - the performance requirements of the various kinds of Road ITS systems; - the tests that are necessary to assess GBPT performances (field tests for this purpose will be addressed by EN 16803-2 and EN 16803-3).