重力垂直梯度的非线性研究

发布时间：2018-04-03 23:52

本文选题：重力　切入点：绝对重力　出处：《中国地震局地震研究所》2014年硕士论文

【摘要】：目前高精度的绝对重力仪精度高达1～2μGal，其用途主要在于研究重力时间变化，并为相对重力联测提供基准和约束。在提供基准和约束时，仪器测量有效高度处的绝对测量值必须归算至地面。因此重力垂直梯度的精密测定很大程度上决定了地面绝对重力基准的准确度。此外在利用FG5与A-10型绝对重力仪分别建立绝对基准时，由于2者测量的有效高度不同(FG5约为130cm；A10约为80cm)，重力垂直梯度空间非线性变化可能会影响到归算结果。因此本文将对重力垂直梯度的测定及其空间非线性变化进行深入的研究，以证实重力垂直梯度非线性变化的存在性，，和对高精度绝对重力测量结果的影响。本文主要研究内容与成果如下： 1、建立多种实际地形条件的地形模型，正演计算重力垂直梯度空间非线性变化，为空间非线性变化观测方案的制定和完善提供基础。 2、利用2台CG-5型相对重力仪和2台Burris型相对重力仪对28个具有代表性的重力基准点在80cm和130cm高度处与墩面之间进行多个往返闭合联测，测定重力垂直梯度，并估算其精度。 3、为了有效验证重力垂直梯度空间非线性变化，在秦岭沣峪口和二测中心开展了进一步的观测实验。测量中在顾及现有不同绝对测量仪器有效高度的同时，增设一个100cm高度进行垂直梯度测定，给出了多高度重力垂直梯度测量结果及其拟合多项式。 4、根据计算得到各点重力垂直梯度测量值，分析重力垂直梯度的空间非线性变化。结果表明：重力垂直梯度的非线性变化在特定的地形条件下确实存在，最大空间非线性变化量可达到0.125μGal/cm，并与理论试算结果基本一致。
[Abstract]:At present, the precision of the high precision absolute gravimeter is as high as 1 ~ 2 渭 Gal. its main purpose is to study the variation of gravity time, and to provide the datum and constraint for the relative gravity simultaneous measurement.In providing the reference and constraints, the absolute measurements at the effective height of the instrument must be reduced to the ground.Therefore, the accuracy of the ground absolute gravity datum is largely determined by the precise measurement of the vertical gravity gradient.In addition, when using FG5 and A-10 absolute gravimeter to establish absolute datum separately, the spatial nonlinear variation of gravity vertical gradient may affect the calculation result because the effective height of the two measurements is about 130 cm / A10 is about 80 cm ~ (-1) because of the difference of effective height of the two measurements.In order to confirm the existence of the nonlinear variation of gravity vertical gradient and its influence on the results of high precision absolute gravity measurement, the measurement of vertical gravity gradient and its spatial nonlinear variation will be studied in this paper.The main contents and achievements of this paper are as follows:1. The terrain model of various actual terrain conditions is established, and the spatial nonlinear variation of gravity vertical gradient is calculated forward, which provides the basis for the formulation and improvement of the observation scheme of spatial nonlinear change.2. Using two CG-5 relative gravimeters and two Burris relative gravimeters, 28 typical gravity datum points are measured at the height of 80cm and 130cm between the piers and the piers. The vertical gradients of gravity are measured and their accuracy is estimated.3. In order to effectively verify the spatial nonlinear variation of gravity vertical gradient, further observation experiments have been carried out in the Qianyukou of Qinling Mountains and the second Survey Center.Taking into account the available effective height of different absolute measuring instruments, a 100cm height is added to measure the vertical gradient. The results of multi-height gravity vertical gradient measurement and its fitting polynomial are given.4. According to the calculation, the measured values of vertical gradients of gravity at various points are obtained, and the spatial nonlinear variation of vertical gradients of gravity is analyzed.The results show that the nonlinear variation of gravity vertical gradient does exist under certain topographic conditions, and the maximum spatial nonlinear variation can reach 0.125 渭 Gal / cm, which is basically consistent with the theoretical results.
【学位授予单位】：中国地震局地震研究所
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P223

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