Portal de Periódicos da CAPES

Effects of height acceleration on Geosat heights

1990; American Geophysical Union; Volume: 95; Issue: C3 Linguagem: Inglês

10.1029/jc095ic03p02843

2156-2202

D. W. Hancock, R. L. Brooks, Dennis W. Lockwood,

GNSS positioning and interference

A radar altimeter tracking loop, such as that utilized by Geosat, produces height errors in the presence of persistent height acceleration h a . The correction factor for the height error is a function of both the loop feedback parameters and the height acceleration. The correction, in meters, to the sea surface height derived from Geosat is −0.16 h a , where h a is in meters per second per second. The errors induced by accelerations are produced primarily by changes in along‐track geoid slopes. The nearly circular Geosat orbit and dynamic ocean topography produce small height acceleration values. Methods of using sea surface tracking data from Geosat and altimeter tracker simulation to calculate h a have been evaluated over various time intervals and topographically interesting geoid areas. One of the areas studied in some detail encompasses the Marianas Trench and the Challenger Deep, in the west central Pacific Ocean. Histograms of sea surface height corrections due to range accelerations have also been determined from 24‐hour segments of Geosat global data. The findings are that 20% of the Geosat measurements have acceleration‐induced errors of ≥2 cm, while 8% have errors of ≥3 cm.