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讨论了一种在一般闭区间上连续的无穷级数展开方法,针对测量和地图学中常用纬度间正反解等一类问题,给出了一种傅里叶级数解算方法,并进行了相应的理论分析和计算。基于Mathematica计算机代数系统,推导出常用纬度与大地纬度间正反解的级数展开式,表明运用傅里叶级数解法可以简单表示和计算一类复杂奇函数的正反解无穷展开式。算例分析验证表明,该方法推导出的纬度正反解展开式是正确的。傅里叶级数方法为分析一类正反解问题无穷展开式的一般系数和形式提供了理论分析依据,具有通用性,丰富了纬度正反解变换的相关理论。 相似文献
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针对不断大型化和多样化的船舶与海洋结构物舱室,为适应其舱容测量需求,借鉴传统的容量比较法和几何测量法,提出了一种新的高效、准确、适用性强的舱容测量方法。新测量方法采用间接积分计算舱容思路,包含实验与计算两个部分;实验中标准容器注水和未知体积大量注水交替进行,再将实验数据转化为可以描述舱容变化趋势的水线面积数据;计算部分基于水线面积数据、采用收敛性较好的样条插值方法得到近似水线面积曲线,并进一步积分得到测量舱容曲线。通过算例验证,相对于传统测量方法,该方法可以更方便、高效地完成大容量舱的容积测量,同时具有很高精度;并可根据舱体特点灵活安排测量方案,更好地解决测量效率与精度间的矛盾。 相似文献
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通过对RTK测量工作原理的分析，得出单基站单采样RTK测量方法在实际应用中的缺点，从而提出了双基站双采样的测量方法，并在天津临港工业区测量项目中进行了实际应用。通过该项目测量成果，分析了采用双基站双采样的RTK测量方法，可有效消除基准站坐标误差对采样点平面坐标的系统影响，消弱对流层随机变化对RTK高程测量的影响，从而使RTK平面坐标测量满足城市一级导线测量的需要，使RTK高程测量接近或达到四等水准测量的精度。 相似文献
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The present study aims at the design and making of measuring instrument of whole direct method for bed shear stress under two-dimensional water-flow co-action. The instrument combines the traditional strain gauge with a precise pressure gauge, and adopts the method directly measuring the difference between the lateral hydrodynamic pressure and different head pressures on both sides of the force plate. As a result, such an instrument solves a technical puzzle of the past strain gauge, i.e. the difficulty to set apart shear stress and lateral force. Static force test and sink test both prove that the instrument is precise, stable and applicable to the measurement of rough beds with different shear stresses. 相似文献
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针对球谐函数定积分计算中Legendre函数递推问题展开研究,分析了标准向前列推法、Belikov法、跨阶次法、X数法以及顾及麦克劳林级数展开式对球谐函数定积分计算的影响。利用Eigen6c-4地球重力场模型计算扰动引力梯度径向分量,分析不同方法之间的差异。实验表明,不考虑麦克劳林级数展开式时4种方法的相对精度在高纬度地区较差,但计算模型扰动引力径向分量的精度一致,结合麦克劳林级数式可提高高纬度地区定积分计算的相对精度,但会降低中低纬度地区定积分计算的精度,并且对高纬度地区扰动引力径向分量的影响极小,但会严重降低低纬度地区扰动引力梯度计算的精度。 相似文献
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Kern E. Kenyon 《Journal of Oceanography》1997,53(1):89-92
The effects of the gravity torques acting on the angular momentum of surface gravity waves are calculated theoretically. For
short crested waves the gravity torque is caused by the force of gravity on the orbiting fluid particles acting down the slopes
of the crests and troughs and in the direction parallel to the crests and troughs. The gravity torque tries to rotate the
angular momentum vectors, and thus the waves themselves, counterclockwise in the horizontal plane, as viewed from above, in
both hemispheres. The amount of rotation per unit time is computed to be significant assuming reasonable values for the along-crest
and trough slopes for waves in a storm area. The gravity torque has a frequency which is double the frequency of the waves.
For long crested waves the gravity torque acts in the vertical plane of the orbit and tries to decelerate the particles when
they rise and accelerate them when they fall. By disrupting the horizontal cyclostrophic balance of forces on the fluid particles
(centrifugal force versus pressure force) the gravity torque accounts qualitatively for the three characteristics of breaking
waves: that they break at the surface, that they break at the crest, and that the crest breaks in the direction of wave propagation. 相似文献
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The subject of wave impact on offshore structures and their components is important to vessel designers and operators for many reasons. They are often required to quantify these impact loads. Standard methods for wave load prediction will underestimate the forces on these structures due to intermittent loading. This necessitates the use of physical model tests to establish wave impact loads. The model measurement systems are designed to have high stiffness. This ensures that the natural frequency of the structure is above the wave frequency. However, it is widely believed that impacting waves contain high-frequency energy components that cause the structure to vibrate at its modal frequencies. This impact-induced vibration is recorded by the measuring system as a force (inertial force), and corrupts the actual applied force measurement. Before scaling can occur, the inertial force must be removed from the measured signal.A number of techniques for removing inertial force from measured signals are described in the published literature. Three methods are discussed, implemented and compared in this paper. The algorithms and procedures are presented. Each technique contains inherent and unique problems, while some are common to all methods.Neither of the techniques produced results that are fully satisfactory. The main problem is unwanted high-frequency content after the application of the methods. While neither method offers the perfect solution, the use of digital filtering techniques is recommended based on their relative performance and ease of implementation. 相似文献
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一种三角高程测量新方法 总被引：1，自引：0，他引：1
三角高程测量是目前常用的一种高程测量方法，但在实际工作中，由于过程麻烦，要求实地施测数据较多，因而测量结果误差较大，存在明显的不足。根据作业中的实际，通过对三角高程原理的分析，提出一种三角高程测量的新方法，分析了其测量原理、使用过程以及优势，并应用于实践。 相似文献
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重力场计算中，经常需要计算以有限阶球谐级数表示的重力场元。常规计算中除需存储(N 1)^2个系数值外，还需迭代计算出(N 2)(N 1)／2个完全正常化勒让德函数值。Clenshaw求和法不需要计算单个球谐函数值而直接计算级数和，因而计算速度上有所提高。总结了球谐函数的零阶导数级数和，并推导了一阶导数级数和。通过数值试验，对于任意点的重力场元，使用C1enshaw求和法计算零阶导数球谐函数和比常规方法节省一半的时间，一阶导数球谐函数之和的计算速度提高幅度不大，并分析了其中的原因。 相似文献
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