This plot displays the long-term tracking performance of a station based on the daily percentage of GPS observations. This percentage corresponds to the ratio of the number of complete observations (both the L1 and L2 frequencies are observed) with respect to the number of predicted observations. Input are the daily RINEX observation file, and the RINEX navigation message, needed to compute the predicted observations.

The percentage, given in brown, is computed for a fixed elevation cut off angle of 15°. The percentage, given in red, is computed for a fixed elevation cut off angle of 0°. Up to the year 2005, the percentage in red was computed using a computed elevation cut off angle (defined as the elevation below which no observations were found).

The EPN guidelines request that a station has a clear horizon above 15° which means that it is expected that the 15° value is close to 100%.

Other periods: