Cross-Calibration and Errors Analysis of Ionosphere Correction in Satellite Altimetry

The single-and dual-frequency ionosphere corrections in satellite altimetry are analyzed in detail.Taking Topex dual-frequency ionosphere corrections as an example,RMS of cross-over difference can be reduced upto 5.7-7.3 mm by along-track filtering of low-pass Gauss.Then,the filtered Topex ionosphere corrections are cross-calibrated with DOIRS,IRI2007 and GIM models that are established by measurements of global continuous GPS tracking stations.The results show that the accuracy of DORIS and GIM is higher than that of IRI2007.The statistics of difference between the filtered Topex dual-frequency ionosphere correction and that from these models show a systematic bias of 10-15 mm.