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Envisat Radial Orbit Accuracy Assessment

Indicators of the radial accuracy of the Envisat precise orbit are the laser residuals (currently at the level of 2 cm) and the radial component of the comparison with external orbits

Another measure of the radial orbit accuracy is the internal consistency of the orbit determination method, which is monitored in the following way: Every time a new 5-day orbital arc is available, the first 2 days of this arc will overlap the last 2 days of the previous arc. The comparison is done over the middle (1-day period) of the 2-day overlap. The following plot shows the RMS history of these comparisons.

Notice that starting of October 2002 Doris doppler data for Envisat became available on a routine basis and has been included in the Precise orbit determinaton from then onwards.