Influence of InSAR altimetry errors on relative height of ocean surface and marine gravity computing

Satellite altimetry plays a great role in marine gravity detection, which contributes a lot in geodesy and geophysics. However, the traditional satellite altimetry mainly measures ocean surface height along the satellite track, which leads to the poorer accuracy of east components of vertical deflections than the north components, since the inclinations of the altimetry satellite are usually close to 90^。 in order to obtain a large coverage in the earth surface. In addition, it's difficult to calculate gravity gradients with high accuracy using the traditional altimetry observations. These limitations may be overcome by a new altimetry technology, the so called InSAR altimetry, which can achieve two-dimensional ocean surface height measuring. The relative heights of the ocean surface can be used to compute vertical deflections, which can be further used to derive gravity anomalies and geoid. This paper firstly analyzes the relative height accuracy of the InSAR altimetry. Then accuracies of vertical deflections and gravity anomalies are evaluated for InSAR altimetry. Several numerical simulations are conducted to show influences of the random errors and system errors of InSAR altimetry on relative height, vertical deflections and gravity anomaly computing.