Differences between NRT ROB-TEC IONEX product and post-processed IGS and ESA products, from 181 days of data covering the end of 2012 and the beginning of 2013 (17,376 maps). Left: mean differences for the entire period. Middle: standard deviation of the differences (1σ). Right: profile of the mean differences extracted from the maps with their standard deviation. The red (longitudinal) and blue (latitudinal) lines correspond to the two tracks shown on the maps. Top: differences between post-processed IGS and NRT ROB-TEC maps. Bottom: differences between post-processed ESA and NRT ROB-TEC maps.