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Abstract

As a technical memorandum for the TIGA/SEAL project, this report describes the procedure and scheme of GPS data processing and product provision at GFZ for monitoring the vertical motion at tide gauge benchmarks to study the global eustatic sea level change. As one of the TIGA analysis centers (TAC), GFZ is processing data from about 370 GPS stations in three lines: backward reprocessing till 1994, forward processing with 66-week latency and one-week delay processing in parallel with IGS as part of IGS activities. The quality of the station coordinate solutions is assessed by comparing with o±cial IGS combination solutions and other TACs' solutions. The consistency with IGS solutions is 4 - 1 mm in the horizontal components, and 8 - 4 mm in the height component, improving with time. The larger discrepancy in earlier time indicates the improvement of TIGA reprocessing. The consistencies with other TACs are not as good as that with IGS. This may come from twofold effects. On the one hand, GFZ TIGA solutions also contribute to IGS. So, the IGS combination solutions should be internally consistent with GFZ TIGA solutions to a certain extent. On the other hand, the differences on software package, strategy and the size of network may also cause a worse consistency among each other. However, the combination of various TACs' solutions gives feedback to improve the single contribution and by this the final products.