【作者】 褚坤；

【导师】 戴永寿； 张杰；

【作者基本信息】 中国石油大学 ， 信息与通信工程， 2010， 硕士

【摘要】 卫星测高技术对于观测全球范围内全天候、重复准确的海洋信息具有极为重要的意义。利用高精度的观测值反演重力异常是获得海洋重力异常的重要途径之一。观测值的精度与反演重力异常的精度评价直接影响着高精度的海洋重力异常的确定。本文针对目前交叉点平差计算过程复杂及误差模型不完善的缺点,改进了交叉点平差方法中的误差模型。该误差模型不仅考虑了径向轨道误差,同时考虑了多种系统误差干扰的综合效应,既包含了误差的线性变化部分,也包含了误差周期性变化的部分,同时又根据每条轨道的数据点数不同,选用不同参数的误差模型,并利用条件平差方法进行交叉点平差。计算结果表明,该方法计算过程简单,不存在秩亏问题,而且平差精度与传统方法相当,提高了结果的稳定性和可靠性。可见基于改进误差模型的条件平差方法更为实用。目前利用实际船测数据评价反演重力异常精度都只是简单给出均方根误差,并没有针对重力异常分布特点进行评价。为了更详细的评价南海部分区域重力异常反演精度,以及探讨能否用卫星测高反演重力异常填补实际船测重力异常数据的空白区的问题,本文采用了总体对比和分级分区对比方法评价了反演重力异常的精度。总体对比结果表明卫星测高数据反演的重力异常精度为7.42mGal,反演精度较高,结果可信。高精度的重力异常数据大多集中在-30mGal~30mGal之间,根据重力异常的定义可见该分级对比结果正符合实际情况,表明地球重力场本身对卫星测高的精度有着较大的影响。选择中沙群岛空白区以南和以北两个区域进行分区对比,两区域的反演精度均高于整个区域的反演精度,表明在中沙群岛附近卫星测高反演的精度较低,用卫星测高反演重力异常填补实际船测重力异常空白区的可行性有待进一步探讨。更多还原

【Abstract】 The satellite altimetry technique has very important meanings for observing all-weather, duplicative and accurate marine information in the worldwide. Using high-precision observations of inversing gravity anomaly is one of important channels to obtain marine gravity anomaly. The accuracy of observed values and the accuracy assessment of inversing gravity anomaly affect directly the determination of high-precision the marine gravity anomalies.Focusing on the shortcomings of complexity in current crossover adjustment process and imperfect of error models, the error model has been improved in the crossover adjustment method in this thesis. This error model is considering the radial orbit error while taking a variety of composite effects produced by the interruption of systematic errors into account. It includes not only the linear part of the error but also the periodical part of it. At the same time, according to the different data points on each track, the error model of different parameters is chosen, and crossover adjustment is done by the use of conditional adjustment. The results show that the calculation process of this method is simple without rank deficient, and the accuracy of the adjustment is similar with the results obtained from traditional methods. It improves the stability and reliability of the results. It can be seen that conditional adjustment based on improving error models is more practical.At present, accuracy assessment on the inversion of gravity anomalies with the boat test data is just to suggest the root mean square error simply, without considering the characteristics of gravity anomaly distribution. In order to get more detailed assessment on inversion precision of gravity anomalies in some regions of South Sea, and discuss whether satellite altimetry inversing gravity anomaly can fill the blank areas where the actual boat test data can’t be measured or not, this thesis evaluates the precision of inversing gravity anomalies with the comparative methods of overall method and zoning classification. The overall comparative results indicate that the accuracy of inversing gravity anomalies measured by the satellite altimetry is 7.42 , a high precision. The result is credible. High-precision gravity anomaly data mostly is concentrated from -30 mGal to 30 mGal . The comparative results of the classification coincide with the actual condition according to the definition of gravity anomaly. It shows that the earth’s gravity field itself has a great impact on the accuracy of satellite altimetry. The south and the north areas of Zhongsha Islands blank area are selected to compare partitively, and the inversion accuracy of the two areas is higher than that of the whole area. It shows that the precision inversed by satellite altimetry is lower near Zhongsha Islands, so the feasibility of filling the blank areas which the actual boat test data can’t measure with satellite altimetry inversing gravity anomaly is to be further explored.更多还原