线性不等式约束平差模型的一种解算方法

不等式约束是实际测量中存在的一种约束,本文利用整标集法求解附线性不等式约束平差模型。首先了介绍带有不等式约束平差的最小二乘问题转化成凸二次规划问题,然后在Kuhn-Tucker条件下把二次规划问题转换成线性互补问题的基础上,利用整标集法来求出参数的最佳估值,最后通过一个数值算例来说明了该方法的可行性。     

Contribution of new AAM data source to δLOD excitation

Data sets of the changes of the length of day (ΔLOD) measured by space geodetic techniques and of the atmospheric angular momentum (AAM) derived from global meteorological data by the National Meteorological Center (NMC) and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) are used to reanalyze and study the excitations of ΔLOD, and to examine and compare the contribution of each AAM series to ΔLOD. The main results are as follows. 1. The AAM reanalyzed with the assimilated global meteorological data by NCEP/NCAR are more accurate and have lower noise than the original AAM derived by NMC. The NCEP/NCAR-based AAM is more consistent with the changes of the length-of-day series. 2. The NCEP reanalysed AAM data may better explain the non-tidal LOD variations on intraseasonal to interannual time scales, especially on the quasi-biennial time scale. The atmosphere cannot, however, explain all LOD variations; other excitation sources are possible. 3. The effects of atmosphere on the estimated values of tides for ΔLOD components up to a month are weak. The preliminary results of the annual and semiannual tides can be estimated after removing the effects of atmosphere from ΔLOD. Received: 27 May 1998 / Accepted: 22 March 1999     

方差-协方差分量估计公式等价性的进一步证明

通过附有条件的间接平差模型进一步证明各类方差-协方差分量估计公式之间的等价性。     

自聚焦光纤中传导模的场分布

从亥姆霍兹方程出发，导出了自聚焦光纤中传导模在圆柱坐标系中的场分布形式，并给出了几个低阶模的分布图。     

Late Cretaceous-Cenozoic history of the Lake Baikal depression and formation of its unique biodiversity

Independent methods of geological and molecular-biological chronologies have made it possible to define generally corresponding stages in the geological and biological evolution of the environments and communities of Lake Baikal since the Late Cretaceous, i.e., during the last 70 myr. All the abiotic elements drastically changed during geological evolution, with destruction of existing and formation of new natural complexes. Nevertheless, some specific zones retained relicts of former settings. The resulting present-day natural complex includes elements of different ages and geneses. Similar to different natural zones of the present-day Earth, which are populated by different biocoenoses, stages in the development of abiotic elements are also characterized by different faunal and floral assemblages. Some taxa were replaced by others, and the resulting aqueous biota of Lake Baikal includes different-age and ecologically different elements. The oldest groups of Baikal organisms appeared approximately 70 Ma ago, although the largest proportion of the lake biota started forming 4–3 Ma ago in response to the most drastic changes in the abiotic elements of the environment. The youngest taxa appeared 1.8 to 0.15 Ma ago, i.e., during the period when superdeep lake environments and mountainous glaciations were developing. The chronological coincidence of main stages in development of abiotic and biotic elements of the nature indicates their relationships. Particular transformations of abiotic elements and the probable mechanism of their influence on the evolution of living communities are also considered.     

侧扫声呐声波掠射角对海底管道检测的影响

在侧扫声呐系统检测海底管道的过程中,声波掠射角是影响检测效果的重要因素。本文针对影响侧扫声呐声波掠射角的主要因素进行了系统研究,推导出声波掠射角与其影响因素的关系表达式,并给出了考虑管径条件下海底管道悬空高度的计算式;进行了不同声波掠射角下侧扫声呐系统检测海底管道的试验,试验结果表明,当侧扫声呐声波掠射角介于14°~20°时,检测效果最好,声波掠射角过小或过大,均会使检测结果出现较大误差。     

面向第二次全国地名普查的数字化调查系统建设研究

针对第二次全国地名普查中现有技术路线的不足,提出了基于移动GIS的数字化调查解决方案。结合地名普查的实际要求,详细介绍了数字化调查系统的系统构架、数据组织、系统功能等,并探讨了系统实现的关键技术。通过实际应用,验证了系统建设的合理性和可操作性,为各地名普查工作提供了较好的参考和借鉴。     

测量机器人的关键技术

本文提出了测量机器人概念,重点分析了测量机器人的组成框架及关键技术,聚焦定位与建图、场景感知、路径规划及多机协同等测量机器人前沿研究领域,综述了最新研究进展,并剖析了当前面临的技术难题,简述了测量机器人的发展机遇.     

冰川和常年积雪常态化地理国情监测开展模式初探

应“十三五”开展常态化地理国情监测之需求,以冰川和常年积雪为监测对象,对冰雪常态化地理国情监测的开展模式进行了初步探索。主要内容有：冰雪监测内容、监测周期和监测方法,冰雪统计分析与评价。对于冰雪统计分析与评价,主要结合相关行业需求,重点在于指标构建。