自适应联邦滤波器在GPS-INS-Odometer组合导航的应用

针对多传感器观测信息较多、计算效率较低、对动力学模型误差稳键性不佳的问题,提出了一种自适应联邦滤波器并应用于GPS-INS-Odometer组合导航。首先介绍GPS-INS-Odometer组合导航的动力学模型和观测模型,比较分析了信息分配因子和自适应因子的共同特性,论证了联邦滤波器和自适应滤波器的等价性及其等价成立条件,提出了自适应联邦滤波器的信息分配因子构造方法。最后利用实测数据验证了算法的有效性。结果表明,相比于基于GPS和Odometer(里程计)初始方差构造信息分配因子的联邦滤波器,本文提出的自适应联邦滤波器兼容了联邦滤波器高效计算效率,且具有较好的抵抗动力学模型误差效果,能够有效削弱多传感器动力学模型误差对于导航解算的影响,对直接可测参数和间接可测参数的精度提高均起到了积极的作用。     

基于部分最小二乘岭估计的粗差定值定位

在利用部分最小二乘原理进行粗差定值定位时,模型的法方程矩阵可能存在病态性,使得到的粗差定值定位结果不可靠。文中针对观测数据包含多个粗差且法方程病态问题,利用岭估计处理病态问题,建立部分最小二乘岭估计的粗差定值定位方法,给出粗差搜索步骤,利用迭代算法实现多个粗差的定值和定位。通过模拟算例分析部分最小二乘法、部分最小二乘岭估计在粗差搜索方面的效果,从另一个角度探讨粗差处理方法,推广现有的误差理论,证明文中方法的有效性。     

Decoding the Development Strategy of a Major Retailer: Wal-Mart's Expansion in the United States

This research aims to provide insight regarding Wal-Mart's retail development strategy in its expansion across the continental United States. The study examines store location patterns and relationships between Wal-Mart's store and distribution center locations and markets. The study shows that, although radial expansion is broadly characteristic of the dense store patterns that have been well established for Wal-Mart at the national level, expansion patterns at the regional level are consistent with a selective process based on factors other than store density. These results provide a new perspective on Wal-Mart's expansion, providing insights of value to retail practitioners and local government.     

沂蒙缺水山区地下水赋存规律及找水定井范例

沂蒙山区是山东省重点贫困缺水地区,缺水区域分布较广,区内地质条件复杂,找水难度极大。通过综合分析区内气象水文、岩性特征、地质构造及地形地貌等地质因素,初步查明了不同地段含水层的结构和富水性;并结合水文地质调查、物探、钻探等综合勘探方法和手段,实施了探采结合孔8口,成功率100%,满足了区内约3万余人的饮用及300余亩土地灌溉用水需求,取得了良好的经济和社会效益。为我国北方严重缺水山区找寻地下水起到了宝贵的指导和示范作用。     

高陡岩石边坡软体护坡技术设计及施工实践

为了消除济南市燕翅山北侧采矿遗留的高陡岩石边坡的地质灾害隐患,恢复自然植被,通过施工砼基座、施工砼格构梁、砌筑软体生态袋和挂网喷播等多种技术方法进行了综合治理,消除了滑坡和崩塌等地质灾害隐患,整个坡面植被覆盖率超过99%,消除了视觉污染,恢复了当地生态环境,该工程成功的设计及施工实践对类似高陡岩石边坡有很好的指导和借鉴作用。     

The Extra-Area Effect in 71 Cloud Seeding Operations during Winters of 2008–14 over Jiangxi Province,East China

Effects of weather modification operations on precipitation in target areas have been widely reported, but little is specifically known about the downwind (extra-area) effects in China. We estimated the extra-area effect of an operational winter (November-February) aircraft cloud-seeding project in northern Jiangxi Province in eastern China by using a revised historical target/control regression analysis method based on the precipitation data in winter. The results showed that the overall seasonal average rainfall at the downwind stations increased by 21.67%(p=0.0013). This enhancement effect was detected as far as 120 km away from the target area. Physical testing was used to compare the cloud characteristics before and after seeding on 29 November 2014. A posteriori analysis with respect to the characteristics of cloud units derived from operational weather radar data in Jiangxi was performed by tracking cloud units. Radar features in the target unit were enhanced relative to the control unit for more than two hours after the operational cloud seeding, which is indicative of the extra-area seeding effect. The findings could be used to help relieve water shortages in China.     

A Review of Atmospheric Electricity Research in China from 2011 to 2018

Atmospheric electricity research has been conducted actively in China, having profited from the development and application of high temporal and spatial resolution lightning detection and location technologies. This paper reviews the scientific advances made in the field of atmospheric electricity in China from 2011 to 2018, covering the following five aspects:(1)lightning detection and location techniques;(2) discharge processes and parameters associated with rocket-triggered lightning;(3) physical processes in natural lightning and attachment to the ground;(4) lightning activities and charge structure in different thunderstorms; and(5) effects of thunderstorms on the upper atmosphere. In addition, some outstanding questions for future research are outlined.     

东亚副热带西风急流的变化特征

利用1979-2013年NCEP/NCAR再分析资料研究了东亚副热带西风急流的变化特征。结果表明:东亚副热带西风急流中心位置、强度有明显的季节变化,冬季偏东偏南、强度最强,夏季偏北偏西、强度最弱。冬半年东亚副热带西风急流南界、北界年际变化的幅度大,夏半年幅度较小。冬季、春季东亚副热带西风急流范围较大,秋季、夏季小,一年内,偏大年或偏小年的出现不具有季节的连续性。     

公路勘测中应注意的几个问题

结合营口滨海大道勘测设计工程实例,探讨了公路勘测时坐标系统选择、平面控制点点位选定、全站仪三角高程代替四等水准、RTK技术应用等一些问题,并提出了几点结论。     

双经纬仪虚拟像坐标二维直接定位

提出了一种基于虚拟左、右像片像空间坐标系的二维直接定位法,可快速提取工业测量系统两台经纬仪之间的相对定位元素并完成相对定位。它不用进行迭代,既可以在右测站的定位元素未知时进行定位元素的解算,又具有简单清楚的几何意义。最后用算例对算法进行了验证。