EGNOS Time and UTC Disseminated by EGNOS

In the frame of the EGNOS Service Performance Monitoring Support to GSA (SPMS), four time laboratories (OP, INRIM, CNES and ORB) are responsible for the monitoring of the time scales broadcast by EGNOS. These are in particular the EGNOS Network Time (ENT) and the difference ENT?UTC(OP) which is broadcast using a specific message type (MT#12). The monitoring concerns both the stability and the accuracy of these time scales. This paper presents the results of the first year of ENT and MT#12 monitoring. It also explains why different approaches to get ENT can lead to biases of few ns in the results. Finally the paper presents a comparison between the EGNOS Timing performances and the U.S. augmentation system WAAS timing performances.