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航空重力测量数据的滤波与处理 总被引：15，自引：3，他引：12
我国首套航空重力测量系统(CHAGS)于2002年研制成功.本文设计了CHAGS观测数据的滤波处理流程,着重讨论了比力及各项改正的滤波计算方法,提出了'两步滤波法'.基于某航空重力测量实测数据,对测线重力异常的计算精度作了比较和分析,重复测线计算结果表明,CHAGS确定测线重力异常的内符合精度优于±3mGal,相应的波长分辨率为8km;与地面实测数据向上延拓数值比较表明,对于同样的波长分辨率,外部符合精度优于±4mGal. 相似文献
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航空重力测量是使用重力仪、GPS及其他传感器测定地球重力场的一种新型技术，其基本原理是利用重力仪测定包括重力加速度、载体运动加速度以及其他一些加速度在内的总加速度，从观测值中减去利用GPS确定的载体运动加速度，再加上一些改正，得到了重力加速度. 本文推导了确定载体运动加速度的直接解算法的公式，利用某次航空重力测量数据，分别在静态、动态两种情况下，分析了确定载体运动加速度精度. 结果表明：在静态、60s的平滑间隔条件下，载体加速度的确定精度是0.4—0.9mGal；在动态、90s的平滑间隔条件下，整个飞行测段载体运动加速度的确定精度是1—3mGal. 相似文献
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FIR低通差分器的设计及其在航空重力测量中的应用 总被引：15，自引：4，他引：11
根据契比雪夫逼近理论 ,设计了适用于航空重力测量应用的有限冲激响应 (FIR)低通差分器 ,利用模拟模型对滤波器的性能进行了验证 .基于静态GPS试验数据和某地区机载动态GPS摄影定位的实测数据 ,应用FIR低通差分器计算了载体的垂直加速度 ,计算结果表明 ,当滤波时间间隔为 1 0 0s时 ,垂直加速度的确定精度可达± 1— 2mGal. 相似文献
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由于受到国界、测量成本和数据规模等因素的限制,航空重力测量本质上是一种欠奈奎斯特采样方法,本文通过离散傅里叶变换分析了航空重力测量的稀疏性,提出了利用压缩感知理论实现大规模重力异常数据高精度重构的思路。基于压缩感知理论,重力异常数据重构问题可以转化为基于L1范数的凸二次规划问题,本文结合预处理共轭梯度算法,提出了一种改进的内点法来解决此问题。进一步地,我们利用自主研发的SGA-WZ型捷联式航空重力仪在中国某地区进行了航空重力测量试验。通过对试验中测得的重力异常数据进行重构,与常用的线性插值重构方法对比,结果表明:本文提出的基于压缩感知理论的新方法能够以更高的重构精度,更有效地解决大规模重力异常数据的重构问题。 相似文献
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EGM2008地球重力模型数据在中国大陆地区的精度分析 总被引：9，自引：1，他引：8
本文介绍了5′×5 ′的EGM2008地球重力模型及其在全球的精度评价.按照地形变化规律,将中国大陆大致分为7个区域,在10 km网度上,将EGM2008地球重力模型数据与中国地面实测空间重力网格数据进行了对比.由于数据源的问题,中国大陆的模型数据精度普遍低于北美和欧洲.二种数据在地形平坦的东部地区差别较小,向西随着地形复杂程度的增加,二种数据之间的标准差从小于10 mGal增大到50多mGal.畸变点分析表明精度极低的网格点均分布在地形起伏大的地区.总体而言,5′×5′的EGM2008地球重力模型数据在中国大陆将近80％的面积上的精度可达10 mGal之内,可用于小比例尺重力编图和构造研究.在地形起伏较大的中国西部以青藏高原为例进一步比较了EGM2008重力模型和重力测点数据,结果表明在重力点分布稀疏不均匀的地区,平面网格数据难以准确表达重力场信息.由于缺少地面重力数据控制,EGM2008重力模型数据在中国西部精度较低,但模型数据依然在很大程度上提高了空间重力异常信息的丰富程度.将中国区域重力调查成果数据应用于地球模型的构建是一项有意义的工作. 相似文献
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China has developed an airborne gravimetry system based on SINS/DGPS named SGA-WZ,the first system in which a strapdown inertial navigation system(SINS)has been used for airborne gravimetry in China.This gravity measurement system consists of a strap-down inertial navigation system and a differential global positioning system(DGPS).In April 2010,a flight test was carried out in Shandong Province of China to test the accuracy of this system.The test was designed to assess the repeatability and accuracy of the system.Two repeated flights and six grid flights were made.The flying altitude was about 400 m.The average flying speed was about 60 m/s,which corresponds to a spatial resolution of 4.8 km when using 160-s cutoff low-pass filter.This paper describes the data processing of the system.The evaluation of the internal precision is based on repeated flights and differences in crossover points.Gravity results in this test from the repeated flight lines show that the repeatability of the repeat lines is 1.6 mGal with a spatial resolution of 4.8 km,and the internal precision of grid flight data is3.2 mGal with a spatial resolution of 4.8 km.There are some systematic errors in the gravity results,which can be modeled using trigonometric function.After the systematic errors are compensated,the precision of grid flight data can be better than1 mGal. 相似文献
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Integrating the deflections of the vertical along the flight line can yield geoid profiles which are valuable in the study of geodesy and geophysics, fortunately, the deflections can be measured directly by vector gravimetry. Airborne vector gravimetry using a Strapdown Inertial Navigation System and the Global Navigation Satellite System (SINS/GNSS) has shown promising results in previous studies. However, the quality of the SINS and GNSS is a major limitation; in particular, the attitude errors induced by the gyros will result in large measurement errors to the horizontal components of the gravity disturbance, and these measurement errors represent the behavior of low-frequency trend. An airborne vector gravimetry method used to remove the bias and low-frequency trends in the gravity disturbance estimated for each survey line has been developed. This method uses the horizontal components of the gravity disturbance computed from EGM2008 (Earth Gravitational Model 2008) as a reference. Firstly, the horizontal measurement results obtained from the gravimeter are divided into high- and low-frequency components according to the resolution of the EGM2008, and then, the bias and low-frequency trends of the low-frequency components are corrected using a linear fit to the EGM2008 reference data. Finally, the ultimate results can be acquired after combining the high-frequency components and the corrected low-frequency components. The data used was obtained from the SGA-WZ, which is the first strapdown airborne gravimeter developed in China. The results of this method are promising. The internal accuracy of the gravity disturbance's horizontal components for repeated survey lines exceeds 3.5 mGal, and the corresponding resolution is approximately 4.8 km based on 160-s data smoothing and an airplane averaging speed of approximately 216 km/h. After applying the WCF (Wavenumber Correlation Filter), the internal accuracy of the horizontal components exceeds 2 mGal. This can satisfy the requirement of the application in geodesy and solid earth geophysics. 相似文献
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依据航空重力测量基本原理,构建了航空重力异常解算的卡尔曼滤波模型,将新息自适应卡尔曼滤波器(IAE,Innovation based Adaptive Estimation)应用于量测噪声未知的航空重力异常解算.针对IAE滤波器滑动窗口宽度难以准确确定的问题,通过对多个不同滑动窗口新息协方差估计的加权平均,获得改进的IAE滤波器,该IAE滤波器不仅具有量测噪声自适应估计能力,还能实现滑动采样窗口的优化选取.试验结果表明,IAE滤波器可以降低因量测噪声统计信息不明引起的解算误差,改进IAE解算的重力异常误差约为1mGal. 相似文献
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I. Marson 《Geophysical Prospecting》2012,60(2):361-372
We report here the results obtained during a feasibility study that was pursued in order to evaluate the performances of absolute airborne gravimetry. In contrast to relative systems, which use spring‐type gravimeters, each measurement acquired by absolute systems is independent from the others and the instrument is not suffering from problems like instrumental drift, frequency response of the spring and variation of the calibration factor. After a validation of the dynamic performance of the experimental setup in a moving truck, a comparison between the experimental airborne data retrieved over the Swiss Alps and those obtained by ground upward continuation at flight altitude allow us to state that airborne absolute gravimetry is feasible. The first test flight shows a spatial resolution comparable to those obtained by relative airborne gravimetry. For a wavelength on the order of 12 km the absolute value of gravity can be evaluated with an uncertainty of 6.9 mGal. 相似文献
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Optimal Model for Geoid Determination from Airborne Gravity 总被引：2，自引：0，他引：2
Two different approaches for transformation of airborne gravity disturbances, derived from gravity observations at low-elevation flying platforms, into geoidal undulations are formulated, tested and discussed in this contribution. Their mathematical models are based on Green's integral equations. They are in these two approaches defined at two different levels and also applied in a mutually reversed order. While one of these approaches corresponds to the classical method commonly applied in processing of ground gravity data, the other approach represents a new method for processing of gravity data in geoid determination that is unique to airborne gravimetry. Although theoretically equivalent in the continuous sense, both approaches are tested numerically for possible numerical advantages, especially due to the inverse of discretized Fredholm's integral equation of the first kind applied on different data. High-frequency synthetic gravity data burdened by the 2-mGal random noise, that are expected from current airborne gravity systems, are used for numerical testing. The results show that both approaches can deliver for the given data a comparable cm-level accuracy of the geoidal undulations. The new approach has, however, significantly higher computational efficiency. It would be thus recommended for real life geoid computations. Additional errors related to regularization of gravity data and the geoid, and to accuracy of the reference field, that would further deteriorate the quality of estimated geoidal undulations, are not considered in this study. 相似文献
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JIANG Tao LI JianCheng DANG YaMin ZHANG ChuanYin WANG ZhengTao KE BaoGui 《中国科学:地球科学(英文版)》2014,57(7):1637-1644
Regional gravity field modeling with high-precision and high-resolution is one of the most important scientific objectives in geodesy,and can provide fundamental information for geophysics,geodynamics,seismology,and mineral exploration.Rectangular harmonic analysis(RHA)is proposed for regional gravity field modeling in this paper.By solving the Laplace’s equation of gravitational potential in local Cartesian coordinate system,the rectangular harmonic expansions of disturbing potential,gravity anomaly,gravity disturbance,geoid undulation and deflection of the vertical are derived,and so are the formula for signal degree variance and error degree variance of the rectangular harmonic coefficients(RHC).We also present the mathematical model and detailed algorithm for the solution of RHC using RHA from gravity observations.In order to reduce the edge effects caused by periodic continuation in RHA,we propose the strategy of extending the size of computation domain.The RHA-based modeling method is validated by conducting numerical experiments based on simulated ground and airborne gravity data that are generated from geopotential model EGM2008 and contaminated by Gauss white noise with standard deviation of 2 mGal.The accuracy of the 2.5′×2.5′geoid undulations computed from ground and airborne gravity data is 1 and 1.4cm,respectively.The standard error of the gravity disturbances that downward continued from the flight height of 4 km to the geoid is only 3.1 mGal.Numerical results confirm that RHA is able to provide a reliable and accurate regional gravity field model,which may be a new option for the representation of the fine structure of regional gravity field. 相似文献
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位场向下与向上延拓之间存在固有的内在联系,向上延拓解算具有稳定可靠的优良特性,本文据此提出了借助向上延拓信息实现航空重力向下延拓稳定解算的两种方法,分别建立了点对点向下解析延拓模型和最小二乘向下解析延拓模型.其核心思想是,依据泰勒级数展开模型,将位场向下延拓解算过程转换为向上延拓计算和垂向偏导数解算两个步骤,通过第一步的处理有效抑制数据观测噪声对解算结果的干扰,通过第二步的处理成功实现向下延拓反问题的稳定解算,较好地解决了向下延拓解算固有的不适定性问题.分析研究了两种解析延拓模型的计算精度及适用条件,利用超高阶位模型EGM2008建立的模拟标准场数据对两种模型解算结果的合理性和有效性进行了数值验证,证明本文新方法实用易行,具有较高的应用价值. 相似文献