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71.
72.
GPS与INSAR数据融合研究展望 总被引:9,自引:0,他引:9
分析了GPS与INSAR数据融合的必要性与可行性 ,讨论了GPS与INSAR数据融合存在的主要问题 ,进一步探讨了利用GPS数据改善INSAR相位解缠算法 ,利用GPS与INSAR数据融合建立水汽模型和大气层延迟误差改正模型 ,以及GPS高时间分辨率和高平面位置精度与INSAR高空间分辨率和高高程变形精度有效统一的问题。 相似文献
73.
74.
R. Lehmann 《Journal of Geodesy》1997,71(9):533-540
Geodetic surface integrals play an important role in the numerical solution of geodetic boundary-value problems. In many
cases they can be evaluated using fast methods in the frequency domain (FFT). However, this is not possible in general, because
the domain of integration may be non-trivial (as is the surface of the Earth), the kernel function may not be of convolution
type, or the data distribution may be heterogeneous. Therefore, fast evaluation strategies are also required in the space
domain. They are more difficult to design because only one property is left where a more or less fast evaluation strategy
can be built upon: the potential type of the kernel function. Consequently, the idea is not to replace well-established frequency
domain techniques, but to supplement them. Our approach to this problem goes in two directions: (1) we use advanced cubature
methods where the integration nodes automatically densify in the vicinity of the evaluation points; (2) we use powerful computer
hardware, namely MIMD computers with distributed memory. This enables us to evaluate geodetic surface integrals of any practical
complexity in reasonable time and accuracy. This is shown in a numerical example.
Received: 7 May 1996 / Accepted:17 March 1997 相似文献
75.
SLJ型宽频带大动态力平衡三分向加速度计的设计与研制 总被引:5,自引:0,他引:5
文中详尽介绍了三分向力平衡加速度计的技术性能、工作原理和理论计算,给出了技术指标鉴定实测结果和获取地震记录的时程曲线。 相似文献
76.
Two semi-asymmetric flow patterns of typhoons are chosen to qualitatively determine the effect of exchange of horizontal momentum between inflow and outflow layers and the environment on the motion of typhoons. The results show that only the asymmetric flow component (residual after azimuthal mean flow has been removed) could cause a net momentum input into or output from a typhoon and therefore contribute to the changes in speed and direction of the typhoon movement. A typhoon with major inflow and/or outflow channels on its right (left) side would tend to accelerate and turn left (decelerate and turn right); On the other hand, a typhoon with major inflow and/or outflow channels in the rear (front) semicircle would tend to accelerate and turn right (decelerate and turn left). 相似文献
77.
Recovering magnetic susceptibility from electromagnetic data over a one-dimensional earth 总被引:1,自引:0,他引:1
While the inversion of electromagnetic data to recover electrical conductivity has received much attention, the inversion of those data to recover magnetic susceptibility has not been fully studied. In this paper we invert frequency-domain electromagnetic (EM) data from a horizontal coplanar system to recover a 1-D distribution of magnetic susceptibility under the assumption that the electrical conductivity is known. The inversion is carried out by dividing the earth into layers of constant susceptibility and minimizing an objective function of the susceptibility subject to fitting the data. An adjoint Green's function solution is used in the calculation of sensitivities, and it is apparent that the sensitivity problem is driven by three sources. One of the sources is the scaled electric field in the layer of interest, and the other two, related to effective magnetic charges, are located at the upper and lower boundaries of the layer. These charges give rise to a frequency-independent term in the sensitivities. Because different frequencies penetrate to different depths in the earth, the EM data contain inherent information about the depth distribution of susceptibility. This contrasts with static field measurements, which can be reproduced by a surface layer of magnetization. We illustrate the effectiveness of the inversion algorithm on synthetic and field data and show also the importance of knowing the background conductivity. In practical circumstances, where there is no a priori information about conductivity distribution, a simultaneous inversion of EM data to recover both electrical conductivity and susceptibility will be required. 相似文献
78.
设计了IAP (InstituteofAtmosphericPhysics,ChineseAcademyofSciences)AGCM III,对其动力框架作说明和检验 ,时间积分采用改进的非线性迭代法。用Rossby Haurwitz波对框架进行了波型检验、能量检验和波速检验。结果表明 ,非线性迭代 3次的时间积分方案具有较好的稳定性 ,能够有效地抑制短波 ,同时对长波的歪曲较小 ,且时间积分步长可放得较大 ;该框架能够较长时间地保持Rossby Haurwitz 4波波型 ,在积分过程中能够较高精度地保持总有效能量守恒 ;模式计算的Rossby Haurwitz波速为每天西传 1 5个经度 ,这与理伦值很接近。 相似文献
79.
在现有GPS星座和大气球对称假设条件下,利用射线追踪法对掩星事件进行了数值模拟,讨论了大气折射指数垂直分布、LEO卫星轨道倾角和高度对GPS掩星切点水平漂移的影响情况。结果表明:在太阳活动剧烈的白天和夜间两种典型情况下,切点平均水平漂移变化约20 km;对735 km高度的LEO卫星来说,轨道倾角在130°附近时,切点平均水平漂移最小,并随着倾角向0°或180°变化,切点平均水平漂移均增大,但在55°附近时随倾角变化稍有波动;对倾角为70°的LEO卫星来说,当轨道高度从400 km变化到1500 km时,切点平均水平漂移变化约141 km,且随高度增加而单调减小 相似文献
80.