重力异常外部校正问题研究

发布时间：2018-02-13 22:43

本文关键词： 重力异常地形校正高程数据网格间距地形起伏　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：重力资料的研究与应用,在地球构造研究、国土资源调查、矿产勘探以及国民经济其他领域发展中都发挥着重大作用。利用重力仪在野外测量的结果经过零点漂移改正后,再将各测点相对于基点的读数差换算成重力差,得到的重力差需剔除外部因素的影响即重力校正,经过校正后能更加精确的反映由地质构造或矿产资源等密度异常体引起的重力异常。随着重力仪器测量精度的提高及高分辨率地形数据的应用,地形校正精度的高低已经成为重力勘探精度的至关重要的影响因素[1]。地形校正按校正范围划分为近区、中区和远区地形校正,由于近区和中区距离测点较近,对测点地形校正值的影响大,所以提高近、中区地形校正的精度是提高地形校正精度和重力勘探精度的关键因素。本文基于前人的研究基础,从理论和模型两方面进一步总结、完善重力异常外部校正(高度校正、纬度校正、中间层校正和地形校正)的计算方法技术;同时,为了更深入的了解高程数据网格间距及高程数据起伏对用直立方柱体模型计算的近、中区地形校正值精度的影响,选用地形起伏分别为20m、50m和100m的3个测试区,采用不同的高程数据网格间距计算近、中区地形校正值,将距测点由近及远划分为不同的校正区间,研究各区间内受不同的网格间距、地形起伏对地形校正值的影响及各区间的校正误差的计算和对比分析。通过研究分析,0~400m区间地形改正值占近、中区地形改正值的90%以上。但随地形起伏程度的不一样该区地形校正值所占全区地形校正值比例有差异,高程起伏越大,所占比例越大,反之越小。同时误差与高程数据网格间距的大小成正比,网格间距越大,误差越大,但随地形起伏程度的不同误差增大的程度不同,地形起伏较小时,误差随网格间距的增大较平缓,反之较明显。
[Abstract]:The research and application of gravity data, in the study of the earth structure, land resources survey, development of mineral exploration and other fields in the national economy plays an important role. The use of gravimeter after zero drift correction in the field measurement results, then the measuring point relative to the basis of reading difference converted into gravity difference, to eliminate the external influence the factors that the difference of gravity gravity correction, after calibration can more accurately reflect the geological structure and mineral resources caused by the density anomalies of gravity anomaly. With the application of the instrument to improve the measurement precision of the gravity and high resolution terrain data, terrain correction precision has become a crucial factor in the [1]. precision gravity exploration according to the terrain correction correction range is divided into near zone, central and far zone terrain correction, due to the distance near and central point is near to the measuring point shape correction The value of the impact, so as to improve the accuracy of terrain correction, is a key factor to improve the precision and accuracy of terrain correction of gravity exploration. This paper based on previous studies, from two aspects of theory and model further summary, improve the gravity anomaly correction (external height correction, latitude correction, middle layer correction and terrain correction) technology calculation method; at the same time, in order to understand the elevation data grid spacing and elevation data fluctuation to further tilt cylinder model, terrain correction precision, the terrain respectively 20m, 50m and 100m 3 test area, the elevation data of different computing grid spacing near, terrain correction value, the distance measuring points are divided into different calibration interval from the near to the distant, on each interval by different grid spacing, topography on the terrain correction effect and the interval of the school The calculation and contrast analysis of positive errors. Through research and analysis, the interval of 0~400m terrain correction value accounted for nearly 90%, terrain correction value. But the degree is not the same with the terrain topography of the area occupied by the correction value of the terrain correction ratio difference, elevation is greater, the greater the proportion, and vice versa at the same time. Small error and elevation data grid spacing is proportional to the size of the grid, the greater the spacing, the greater the error, but the error with the different terrain increased to different extent, the terrain is small, the error with the grid spacing increases slowly, and more obvious.

【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.1

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