Jean-Michel Lemoine (CNES, France)

All the DORIS Analysis Centers observe a jump in the scale factor of their combined solution in 2012. The introduction of the HY-2A solution seems to cause the largest jump in the DORIS scale. However, some investigations show that the Jason-2 and Cryosat-2 solutions are also responsible of the DORIS scale jump. This contribution in the scale jump seems fully explained by a variation in the number of low elevation measurements included in the processing. We propose here to demonstrate the origin of this scale jump by several tests in particular by taking into account another data format (RINEX) and by processing DORIS data with different cutoff angles. We plan also to analyze the impact of the low elevation measurements on the height station position estimation and the Helmert parameters (scale factor and geocenter).