共查询到19条相似文献，搜索用时 939 毫秒
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大陆上用重力数据和GPS水准数据确定(似)大地水准面,海洋上用卫星测高数据确定(似)大地水准面.由于沿海地区和近岸海域往往缺少完好的重力数据,近岸海域卫星测高数据质量相对较差,两类大地水准面在陆海相接区域精度偏低且存在拼合差.纯几何方法拟合陆海局部区域大地水准面,不能顾及大地水准面的物理特性,拟合结果不稳定.顾及到大地水准面的物理特性,依据其在局部所应满足的数学物理方程,拟合陆海局部区域大地水准面问题,转化为Laplace第一边值问题.讨论了有限元法衔接陆海局部区域大地水准面的数学思想,给出了相应的数学模型. 相似文献
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基于改进Runge定理的调和延拓及其相应的边值问题 总被引：2，自引：0，他引：2
利用改进的Runge定理引入了外大地水准面和外重力位等新概念 ,建立了关于外扰动位的边值问题 ,该问题同时具备了Stokes问题和Mododensky问题的优点 .作为一个整体 ,讨论了外正高的计算和地面重力的归算 ,给出了在O(T2 )量级的精度下确定外大地水准面、地面以及地球外部重力场的方法 . 相似文献
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研究和实施了由卫星测高数据计算垂线偏差，用莫洛 金斯基（Molodensky）公式反演 大地水准面高，由此求得我国海域大地水准面高. 为了检核，将测高垂线偏差利用逆维宁迈 纳斯（Vening Meinesz）公式反演重力异常，与海上船测重力值进行了外部检核；同时还用 司托克斯（Stokes）公式，将上述反演的重力异常计算大地水准面高，与莫洛金斯基公式直 接解得的相应结果进行比较作为内部检核. 在积分计算中充分应用了FFT的严格公式.由重力和GPS水准数据确定的陆地大地水准面，和主要由卫星测高数据确定的海洋大地水准 面，二者之间一般都存在以系统误差为主的拼接差，本文分析了产生这一现象的主要原因, 并结合我国在陆海大地水准面拼接区重力资料稀疏的实际，提出了新的拼接技术，最后将拟 合参数校正中国全部海域的重 力大地水准面，以最大限度地削弱拼接点和制约测高海洋大地水准面可能存在的系统误差. 相似文献
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现代大地测量技术(VLBI,GPS,InSAR,海洋测高,以及重力卫星等)的发展使得全球范围内可以监测到同震变形,例如,位移、重力、大地水准面和应变等.这些大地测量及地球物理信息可用来研究震源机制、地球内部构造、断层反演、大地测量结果解释以及确定震源参数等. 相似文献
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随着GPS/水准及全球重力测量的加密和扩展,获取高精度的似大地水准面或高程异常(ξ)已比较容易,如何进一步研究它和大地水准面或大地水准面高(N)之间的关系(即所谓间接的方法)使大地水准面得到精化,这就是本文的目的,文中对已推导的公式在模型作了验证,对如何利用地形等数据确定扰动重力垂直梯度也作了研究,结果表明:在海拔4000 m的高山地区,当似大地水准面的精度达到cm级时,大地水准面的精度也与之比较接近. 相似文献
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在用环域大地边值理论求解大地水准面的基础上对环域大地逆边值问题的解式作进一步研究.结果表明:①在线性化模式下,环域大地逆边值问题的解与确定大地水准面的传统的移去-恢复法解具有一致性;②在采用移去-恢复法时应注意,尽管移去过程中需调整地球质量,但不能调整参考正常重力场值;③若边界观测采用重力异常值,在采用移去-恢复法时应注意不能恢复移去物质对大地水准面的一阶项影响;④移去-恢复法的向下归算是环域大地逆边值问题解中的调和延拓的线性近似.本文既是对利用环域大地边值理论求解大地水准面的有效性的重要论证,也是对传统的确定大地水准面的移去-恢复法的数学证明. 相似文献
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本文对亚洲太平洋地区地球动力学计划(APRGP,简称亚太网)在1999-2001年采集的三期GPS观测数据,利用GAMIT/GLOBK软件进行了分析处理,得出各期的观测站在ITRF97框架下的三维直角坐标,并根据三期观测数据中的重复观测站进行了速度场计算和地壳形变特征分析。结果表明亚洲大陆板块具有明显的顺时针旋转运动特征;印度板块和澳大利亚板块从西南方向对亚洲大陆板块进行挤压;而西太平洋地区各观测站则向西北方向运动。这些特征与国内GPS区域网观测数据处理得出的结论是一致的,而本文则揭示了更大范围的亚洲太平洋地区地壳形变信息。 相似文献
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目前,在地球动力学和地震预测预报研究领域中,在处理GPS数据时,一般利用精度比较高的每周解(7天解)结果,由于时间较长,每周解只能为中长期的地震预测提供服务,而不能为短期的地震预测提供服务.本文根据北京市GPS地震监测网的高密度和连续性的特点,通过控制影响GPS精度定位因素,对1～7天解的时间序列、相关系数、点位平均精度进行对比分析,研究表明,3天解以上的结果在点位精度、最终的时序变化等指标上都能达到地震短临分析工作的要求. 相似文献
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In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and proposed the concept of using a frequency dilution of precision to describe the quantitative effect of different frequency combinations on the positioning precision. To this end, we computed and plotted the global spatial distribution map of the relative positioning dilution of precision for single-day solution, half-hour solution, and single-epoch solution of the global positioning system(GPS), regional Beidou navigation satellite system(BDS2), future global Beidou navigation satellite system(BDS3), and their fusion systems.Using processing software with autonomous intellectual property rights(GCN and VENUS/ARSNet), we solved the measurement data and examined the positioning precision of the single-day solution and single-epoch solution of GPS and BDS2.The analysis demonstrated that the B1/B2 frequency positioning precision of BDS2 was better than that of L1/L2 frequency positioning of GPS, but the positioning precision of the BDS2 is worse than that of GPS over most of the service region of the BDS2. Further, the positioning precision of BDS3 is better than that of GPS in the Asia-Pacific region, while it is the opposite in other regions. Based on these conclusions, we put forth some optimization recommendations regarding the signal frequency of the navigation system and GPS measurement standards to serve as references for optimizing the system performance and formulating standards. 相似文献
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Improved determination of heights using a conversion surface by combining gravimetric quasi-geoid/geoid and GPS-levelling height differences 总被引：2，自引：0，他引：2
The quasi-geoid/geoid can be determined from the Global Positioning System (GPS) ellipsoidal height and the normal/orthometric
heights derived from levelling (GPS-levelling). In this study a gravimetric quasigeoid and GPS-levelling height differences
are combined to develop a new surface, suitable for “levelling” by GPS. This new surface provides better conversion of GPS
ellipsoidal heights to the national normal heights. Different combining procedures, a four-parameter solution, linear and
cubic splines interpolations, as well as the least-squares collocation method were investigated and compared over entire Norway.
More than 1700 GPS-levelling stations were used in this study. The combined surface provides significant accuracy improvement
for the normal height transformation of GPS height data, as demonstrated by the post-fitting residuals. The best solution,
based on the least-squares collocation, provided a conversion surface for the transformation of GPS heights into normal height
in Norway with an accuracy of about 5 cm. 相似文献
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为分析北斗导航定位系统（BDS）在地壳运动监测领域的数据精度,选取中国大陆构造环境监测网络（陆态网络）2018—2019年川滇地区GPS、BDS多系统观测站点数据,分别对GPS、BDS记录的数据进行解算,从三维坐标解、位置时间序列及速度场等方面,对比分析二者在地壳运动监测中的不同,综合分析BDS对地壳运动监测精度。结果表明,BDS定位精度达到cm级,但仍低于GPS精度,BDS、GPS速度场模型运动方位和速度值有所不同,垂向差异较为明显。总体来看,北斗系统数据满足高精度定位解算要求,可用于监测形变量较大的区域地壳运动。 相似文献
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利用多个全国性的GPS监测网、中国地壳运动主要活动带的区域性GPS监测网以及亚太地区大地测量计划(APRGP)的GPS监测网自1991年以来近10年的GPS资料,通过旋转变换将不同方法得出的各个子网的速度解进行统一,给出一个自恰的、完整的ITR一7框架下的速度场综合解.为了研究中国现时地壳运动在欧亚板块内形变的特征,基于一个现时板块运动模型ITRF97VEL,给出了3类网共260多个站的形变速度场.结果表明中国地壳运动有明显的不均匀性,以南北地震带为界,西强东弱;中国西部受印度板块强烈的冲挤,地壳运动由南向北逐渐减慢,呈现南北向缩短,东西向伸展,有明显的块体特征;喜马拉雅和天山西部分别提供了约15mm/a和9-13mm/a的汇聚速率;拉萨块体有(20.2±1.2)mm/a的伸长;喀喇昆仑一嘉黎断裂的右旋走滑速率和阿尔金断裂的左旋走滑速率分别为2-3mm/a和4-6mm/a,穿过龙门山断裂带的缩短速率小于7mm/a,这些都支持地壳增厚学说;沿阿尔金断裂带到喜马拉雅存在一个NNE弥散带,它是形变速度有东和西分量的分界线,是一个有特殊意义的动力学带.中国东部以走滑为主,东北块体是中国最稳定的地区,华北块体具有较大走滑性,是东部较易变形区. 相似文献
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Comparison of the qualities of recent global and local gravimetric geoid models in Iran 总被引：1，自引：0，他引：1
A number of regional gravimetric geoid models have recently been determined for the Iran area, and a common problem is to select the best model, e.g. for engineering applications. A related problem is that in order to improve the local geoid models, the selection of the best Global Geopotential Model (GGM) model for the region is essential, to be used in a combined solution from GGM and local gravimetric data. We discuss these problems by taking advantage of 260 GPS/levelling points as an external tool for validation of different global and local geoid models in the absolute and relative senses. By using relative comparisons of the height differences between precise levelling and GPS/geoid models we avoid possible unknown systematic effects between the different types of observables.The study shows that the combination of the newly released GRACE model (GGM02C) with EGM96 geoid model fits the GPS/levelling data in Iran with the best absolute and relative accuracy among the GGMs. Among the local geoid models, the newly gravimetric geoid model IRG04 agrees considerably better with GPS/levelling than any of the other recent local geoid models. Its rms fit with GPS/levelling is 55 cm. Hence, we strongly recommend the use of this new model in any surveying engineering or GPS/levelling projects in the area. 相似文献
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本文介绍了在武汉召开的高精度GPS观测资料处理、解释研讨会，会议讨论了在我国该领域的最新进展和存在的问题，指出应该制定适合我国特点的GPS观测资料处理规范，并研制我国自己的高精度GPS观测数据处理软件。 相似文献
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This paper introduces the Global Positioning System (GPS) and considers its role as a technique for use in geomorphological field work. Although valuable on its own, it is apparent that the utility of GPS in geomorphology is enhanced when used alongside Geographical Information Systems (GIS) technology in the field. This paper reviews GPS, considering what it is, the methods available and their relative accuracies, the potential and problems of the technology and its relationship with GIS. Particular attention is given to the application of GPS in geomorphological and related case studies. Examples are presented of the successful use of GPS and GIS to study hydrology and snow patch regime from the recent GeoAltai expedition to Southern Siberia. 相似文献