高分辨率航带影像像控点的布设和基准约束测量     

范业稳  李睿硕  周洪波 《测绘通报》2017,(4):67

推扫式航摄仪所获取的带状影像,其每个像素都具有比较准确的WGS-84坐标。带状影像模型自成刚体,具有很强的稳定性,但其区域网模型精度在高程方面偏弱。受其自身航带影像模型刚性和区域网弱高程模型精度的影响,其像控点布设有其自身的特殊性。在获取具有多重空间基准约束的像控点的过程中,当在像控区域中有CORS基站、GPS控制网、水准控制网等多个空间基准类型可以利用时,可利用IGS站点和EGM2008数据快速验证这些基准的应用有效性,避免已有空间基准的潜在问题,这是保证像控点快速和精确获取的关键。  相似文献   

基于分组排序的水汽层析约束ART算法     

丁楠  张书毕 《大地测量与地球动力学》2017,37(5):482-486

通过研究影响代数重构方法的因素,如松弛因子、投影次序、停止规则、非负约束,针对水汽层析方程组的特点,提出一种基于分组排序的水汽层析约束ART算法（WVTART）,并给出投影排序的去相关原则。实验分析证明,WVTART算法提高了收敛速度以及层析结果的精度。  相似文献   

A recipe for why and how to set up and sustain an experimental catchment     

Daniele Penna 《水文研究》2024,38(5):e15163

Experimental catchments are fundamental elements in hydrological sciences as they provide key data for putting forward and testing hypotheses, developing theories, constraining models, and making predictions. Significant progress in catchment hydrology stemmed from field measurements but increasing costs and risks associated with field work and the availability of big data based on remote sensing, machine learning, and a plethora of models, as well as observations deriving from previous and current sites, raises questions on whether running an experimental catchment still provides individual and community benefits as in the past. In this commentary, I highlight the advantages of keeping experimental catchments alive and propose a personal 10-step “recipe” to set up a new experimental catchment and manage and sustain it in the long term. These suggestions can be useful both to young and less young researchers who are open to facing the challenge of measuring processes in the field and are willing to offer the scientific community new experimental evidence for advancing our current knowledge in catchment hydrology.  相似文献   

模型约束下的在线字典学习地震弱信号去噪方法          下载免费PDF全文

李勇  张益明  雷钦  牛聪  周钰邦  叶云飞 《地球物理学报》2019,62(1):411-420

本文针对噪声成分和噪声结构的复杂性及弱信号的特征,发展了最新的在线字典学习去噪方法.在线字典学习去噪方法是以数据驱动的方式,反复进行学习构建字典方式,求得信号的稀疏性解以实现对信号的去噪,在此基础上,提出了数据驱动与模型驱动联合的模型约束下的在线字典学习去噪方法,先通过模型驱动方式获得一个较优质的学习样本以构建字典再进行去噪处理.通过和传统小波变换进行理论地震合成记录的效果对比,在高噪声比例的弱信号情况下远远优于传统的时频域去噪方法.实际数据去噪处理表明,模型约束下的在线字典学习去噪方法是一种有效的去噪方法,这种联合去噪方式能在高噪声背景下有效地提取出弱信号,具有广阔的推广应用前景.  相似文献   

Two-dimensional data-space joint inversion of magnetotelluric,gravity, magnetic and seismic data with cross-gradient constraints     

Rongzhe Zhang  Tonglin Li  Xinhui Deng  Xingguo Huang  Yongchol Pak 《Geophysical Prospecting》2020,68(2):721-731

In recent years, joint inversion has been widely used for integrated geological interpretation. We extended a data-space joint inversion algorithm of magnetotelluric, gravity and magnetic data to include first-arrival seismic travel-time and normalized cross-gradient constraints. We describe the main features of the algorithm and apply it to synthetic data generated for hypothetical models. For the synthetic data, we find that the joint inversion with multiple parameters is superior to the joint inversion with two or even three parameters, which can reduce the multisolution of inversion results more effectively. Furthermore, data-space joint inversion involves fewer memory requirements and better calculation speeds than traditional model-space joint inversion. The normalized cross-gradient constraints can better couple model parameters of different magnitudes compared with traditional unnormalized cross-gradient constraints, resulting in higher levels of structural similarity among resistivity, density, magnetic susceptibility and velocity models.  相似文献   

基于稀疏约束和多源激发的地震数据高效采集方法          下载免费PDF全文

王汉闯  陶春辉  陈生昌  杜泳  丘磊 《地球物理学报》2017,60(9):3518-3538

地震勘探目标日趋复杂化和精细化,"两宽一高"等采集技术获得了广泛应用,从而导致当前地震数据采集周期越来越长、成本越来越高,如何解决日益增长的勘探成本问题成为当前地震采集领域的研究热点之一.针对上述问题,本文首先开展了基于稀疏性的地震数据高效采集方法理论研究,对地震数据稀疏性基本理论、稀疏约束下随机采样及其数据重建方法进行了深入探讨,提出使用改进的分段随机采样方法灵活地进行实际地震采集测网设计;详细阐述了多源地震激发方法,对多源地震数据分离方法开展了深入研究,提出了基于小窗口中值滤波与稀疏约束联合随机去噪的多源数据分离方法,并在数据分离处理中取得了较好的效果;将上述两种地震数据采集方案有机结合,提出了1)规则多源、随机检波点(DmsRg)、2)随机多源、规则检波点(RmsDg)和3)随机多源、随机检波点(RmsRg)等三种高效采集方案及相应的数据重建方案,满足了后续常规化数据处理的要求,并讨论了多源激发对数据成像的影响.基于Marmousi模型数据的数值试验表明,本文构建的基于稀疏约束和多源激发的高效采集方法理论对于提高地震数据采集效率、降低勘探成本具有重要的应用价值,建立的数据重建方法流程可以取得和常规数据接近的成像结果.本文方法虽然在数值试验中取得了较为理想的效果,但还需要得到野外实际数据采集的进一步检验.  相似文献   

Parallel trajectory planning for shipborne Autonomous collision avoidance system     

《Applied Ocean Research》2019

Collision at sea is always a significant issue affecting the safety of ship navigation. The shipborne autonomous collision avoidance system (SACAS) has the great advantage to minimize collision accidents in ship navigation. A parallel trajectory planning architecture is proposed in this paper for SACAS system. The fully-coupled deliberative planner based on the modified RRT algorithm is developed to search for optimal global trajectory in a low re-planning frequency. The fully-coupled reactive planner based on the modified DW algorithm is developed to generate the optimal local trajectory in a high re-planning frequency to counteract the unexpected behavior of dynamic obstacles in the vicinity of the vessel. The obstacle constraints, ship maneuvering constraints, COLREGs rules, trajectory optimality, and real-time requirements are satisfied simultaneously in both global and local planning to ensure the collision-free optimal navigation in compliance with COLREGs rules. The on-water tests of a trimaran model equipped with a model-scale SACAS system are presented to demonstrate the effectiveness and efficiency of the proposed algorithm. The good balance between the computational efficiency and trajectory optimality is achieved in parallel trajectory planning.  相似文献   

废物地下填埋场选址的地质条件约束     

赫英臣  席北斗  龚斌 《地学前缘》2007,14(6):63-72

当今采矿业仍然使用全陷法开采,致使矿区环境遭到十分强烈的破坏。为了环境保护的需要,德国等许多国家积极开展利用废物进行地下充填的新的采矿法,使矿区环境得到保护以及采矿业达到可持续发展。文中以德国鲁尔矿区为例,充分论述了矿区的地质和水文地质条件对地下填埋场或地下充填场选址的约束,以及如何对矿床的地质和水文地质条件进行充分调查和分析,优选出安全可靠的固体废物的地下填埋场或地下充填场地,使采矿业的发展和环境保护的需求之间达到最优化的联合。重点介绍了德国地下填埋场的充填技术,适合于地下充填废物的筛选;对地下填埋场选址的地质条件约束,主要通过地质、岩性、地质构造分析和水文地质条件约束来确定,最后优选出最安全的地下填埋场。  相似文献   

The constrained politics of the Svalbard offshore area     

Torbjrn Pedersen 《Marine Policy》2008,32(6):913-919

This study identifies some mechanisms through which external factors constrain state behavior. Examining Norwegian governance for the disputed Svalbard offshore area, it finds the behavior of Norway to be constrained in multiple ways by the conflicting policies of foreign powers toward the area. When shaping the management regime of the controversial maritime zones of the former terra nullius Svalbard, Norwegian authorities cautiously consider the possible international ramifications of their actions. Norway's behavior—not only manifested in policy but also in the exercise of contested legislative and enforcement jurisdiction—is curbed amid international disagreements over Norwegian rights in the area.  相似文献   

曲面位场的正则化线性规划法直接反演技术   总被引：4，自引：0，他引：4  

刘展  王万银 《地质与勘探》1999,35(6):62-66

讨论了可用于起伏地形上重磁位场数据直接反演的、正则化的线性规划反演方法,给出了求解模型、求解方法及相关的技术措施。通过理论模型试算,证明了方法的可行性,在某铜镍矿区的应用验证了方法的实用性。  相似文献