Tuesday 23 August 2005

G2

PT0017
Retracking of Geosat data for precise gravity field recovery
Deng, Xiaoli¹, Hwang, Cheinway²
1 School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
2 Department of Civil Engineering, National Chiao Tung University, Hsinchu , Taiwan
Author email: xiaoli.deng@newcastle.edu.au
Ocean altimeter sea surface height measurements extracted from waveform retracking techniques have shown significant improvement in terms of the precision and along-track resolution (eg Maus et al. GJInt 1998). The results of retracking non-repeat waveform data from Geosat Geodetic Mission (GM) are presented in this study. Retracking methods involve both fitting and threshold retracking algorithms developed from previous research. The retracking technique improves the accuracy of the measurements, but also generates a bias in the range estimates because of the noise characteristics of the return waveform. The retracking results are affected by the noise in the fitting algorithm as well as relatively simplistic assumptions in the threshold retracking. We have developed improved retracking algorithms that both reduce the noise effect and improve the accuracy of the range estimate. The retracking technique also estimates the parameters of the off-nadir angle and significant wave height. These estimates have been analysed to find their error characteristics. Results from Geosat GM waveform retracking will provide optimised data sources for gravity field and mean sea surface recovery.

Return to Poster Presentations