线状符号的分解与组合

线状符号是地图上常用的符号,本文在分析其构造原理的基础上,提出了规则线状符号的逻辑构造函数。同时为了能够满足地图的视觉效果需要,讨论了在机助实现过程中的一些算法。     

两种渐消滤波与自适应抗差滤波的综合比较分析(英文)

Two kinds of fading filters and their principles are introduced. An adaptive robust filter is given with corresponding principle. The basic abilities of the fading filters and adaptively robust filter in controlling the in- fluences of the kinematic model errors are analyzed. A practical example is given. The results of the fading filter and adaptively robust filter are compared and analyzed.     

Pinpointing Source of Mekong and Measuring Its Length Through Analysis of Satellite Imagery and Field Investigations

For centuries, explorers and scientists from different countries had made their own conclusions on the source of the Mekong. However, the geographic source of the Mekong is still arguable because of the complexity of the Mekong source water system, inaccessible environment and the varied technologies used by those explorers and scientists. The satellite remote sensing technology has been used to pinpoint the source of the Mekong, associated with the on-the-spot investigations made by the authors in June 1999 and September 2002. The actual length of the Mekong has also been calculated.     

Numerical Simulation for Refraction-Diffraction of Waves in Water of Slowly Varying Current and Topography

A new numerical finite difference iteration method for refraction-diffraction of waves in waterof slowly varying current and topography is developed in this paper.And corresponding theoretical modelincluding the dissipation term is briefly described,together with some analysis and comparison ofcomputational results of the model with measurements in a hydraulic scale model(Berkhoff et al.,1982).An example of practical use of the method is given,showing that the present model is useful to engineeringpractice.     

DEFORMATION AND ROUGHNESS CHANGES OF THE MAIN CHANNEL AND FLOODPLAIN IN FLOOD EVENTS (CASE STUDY )

LINTRODUCTIONAsfear7specificsurveyshavebeenmadeonthemorphologicalbehavioroftheHuaihefox'erinthepast.Someinformationofbeddeformationduringfloodprocesshavebeenobtained.Beingrelativelystable,theHuaihehiverusedtobeineptlytreatedas"fixedbed".Fortunately,tilehydrometricalstationsweredenselydistributedalongtheHuaihehiverinthe1950s,andthevelocitylareamethodwasusedforthedeterminationofdischarge.Themeasurementsofdischargearelistedin"TheDischargeMeasurementsTable"intheHydrologicalYearbooks.Sinc…     

基于GOCE梯度的地球引力场恢复(英文)

Given the second radial derivative Vr r ( P ) |S of the Earth’s gravitational potential V ( P ) on the surface S corresponding to the satellite altitude, by using the fictitious compress recovery method, a fictitious regular harmonic field rrVr r( P )* and a fictitious second radial gradient field Vr *r ( P) in the domain outside an inner sphere K i can be determined, which coincides with the real field Vr r( P ) in the domain outside the Earth. Vr *r ( P)could be further expressed as a uniformly convergent expansion series in the domain outside the inner sphere, because rrVr r( P )* could be expressed as a uniformly convergent spherical harmonic expansion series due to its regularity and harmony in that domain. In another aspect, the fictitious field V * ( P) defined in the domain outside the inner sphere, which coincides with the real field V ( P ) in the domain outside the Earth, could be also expressed as a spherical harmonic expansion series. Then, the harmonic coefficients contained in the series expressing V * ( P) can be determined, and consequently the real field V ( P ) is recovered. Preliminary simulation calculations show that the second radial gradient field Vr r( P ) could be recovered based only on the second radial derivative Vr r ( P )| S given on the satellite boundary. Concerning the final recovery of the potential field V ( P ) based only on the boundary value Vr r ( P )|S, the simulation tests are still in process.     

地球的时变主惯性矩和变化的自转(英文)

Based on the gravity field models EGM96 and EIGEN-GL04C, the Earth's time-dependent principal moments of inertia A, B, C are obtained, and the variable rotation of the Earth is determined. Numerical results show that A, B, and C have increasing tendencies; the tilt of the rotation axis increases 2.1×10-8 mas/yr; the third component of the rotational angular velocity, ω 3, has a decrease of 1.0×10-22 rad/s2, which is around 23% of the present observed value. Studies show in detail that both θ and ω 3 experience complex fluctua-tions at various time scales due to the variations of A, B and C.     

哈萨克斯坦东部斋桑盆地恐龙蛋壳化石与白垩系-古近系界线

在晚白垩世期间,哈萨克斯坦东部的斋桑盆地形成了一个湖盆,一直延续到现在。古斋桑湖中最老的沉积是Tayzhuzgen组,由厚达136m的泥岩、粉砂岩、页岩、石英砂岩、砾岩和淡水石灰岩红层组成。按照当地的地层名称,Tayzhuzgen组包括Manrak、Tayzhuzgen、Aulisbulak、Aktobe、Dysum bay和Kiin Kerish层。在斋桑湖以南的Tayzhuzgen河附近一个地点的Tayzhuzgen组下部,发现了恐龙蛋壳碎片,蛋壳至少包括有两个主要类型:圆形蛋类和长形蛋类。恐龙蛋壳指示了Tayzhuzgen组下部的时代为晚白垩世(可能是马斯特里赫特期)。在本组的较高层位,发现了晚?古新世的植物化石,因此斋桑盆地的白垩系-古近系界线在Tayzhuzgen组内部。在Tayzhuzgen组中,白垩纪与古新世化石层之间的地层间隔只有约50m,由此推测在Tayzhuzgen组内部可能存在一个或多个不整合,或是本组的中部为凝缩沉积,即在白垩系-古近系界线处的沉积速率非常缓慢。Tayzhuzgen组顶部有一个显著的不整合,那里中或晚始新世(Arshantan,Irdinmanhan或Egilian陆生哺乳动物"期")的地层存在于含哺乳动物化石剖面的底部。斋桑盆地的白垩系-古近系界线位于古斋桑湖沉积剖面的下部。这不是一个完整的界线剖面,可能是一个包含有一个或多个不整合和/或一个由慢速沉积造成的凝缩剖面。     

一种复杂海天背景下的红外舰船目标自动检测方法

提出了一种红外舰船目标检测算法。首先,利用设计好的频域组合高通滤波器对原始红外图像进行处理,以得到舰船目标可能存在的区域即目标潜在区;然后,对获得的目标潜在区进行尺度自适应的局部阈值分割,进而提取出较为完整的舰船目标或者虚假目标;最后通过检测吃水线特征来筛选出正确的舰船目标。实验结果表明,此算法能够有效地检测出复杂海天背景条件下的红外舰船目标,且具有一定的时效性。     

基于非差观测的网络实时动态定位方法及其在连续运行基准站跨网服务中的应用

基于非差观测的网络实时动态定位(RTK)方法通过提供每颗卫星的误差改正量,使网内用户获得与网络RTK方法等价的快速精密单点定位服务。当用户跨越连续运行基准站(CORS)网内由不同参考站组成的子网(参考子网)甚至跨越不同CORS网时,都能有效避免因所选取的主参考站变化而引起的模糊度重新初始化,从而保持观测时段内用户定位结果的连续可靠和跨CORS网服务时算法上的无缝衔接。通过对海上实测动态数据处理结果的分析,验证该方法的定位精度、初始化时间与现有网络RTK方法在量级上的一致性,以及跨不同参考子网和CORS网时实现无缝衔接的有效性。