3S技术应用现状与发展趋势

3S技术出现至今,已在诸多领域成功运用并产生了巨大的价值。文章简单介绍了3S三大组成部分:GIS、RS、GNSS的基本概念,分析了3S技术目前在农业、生态环境监测、土地资源管理以及智慧城市方面的应用现状以及对其在该方面未来的发展趋势进行展望。最后对目前3S在应用中遇到的一些问题进行了探讨,给未来3S技术的发展提供一些参考。     

Land surface deformation parameter estimation using persistent scatterer interferometry approach in an underground metal mining environment

Persistent scatterer interferometry (PSI) is a major advancement in radar interferometry for detecting and monitoring land deformation. PSI is the most advanced class of differential interferometric synthetic aperture radar (DInSAR) techniques. The technique conquers the main drawbacks of the conventional DInSAR technique by identifying radar targets having stable backscattering characteristics in time. These targets are termed as persistent scatterers (PSs). The higher the number of PSs for a study area the higher the accuracy of the results will be, which is most common for deformation analysis in urban areas. However, for non-urban or highly de-correlated areas, PSs density collapses significantly, which needs to increase for optimal results. For this purpose, partially coherent/distributed scatterers (DSs) are being exploited in addition to the PSs. The field surface of this study is one of the copper-rich mining belts in India, which consists of two major underground metal mines. Scatterer characterziation of the field surface under study suggests that most of the scatterers are DSs and very few scatterers under the influence of the mining zone are PSs. In addition to this, a preliminary investigation of deformation characteristics of the field surface under study reveals that the spatial extent of deformation is small/localized along with slow and non-linear deformation. Keeping in view scatterer and deformation characteristics of the field surface under study, in this research paper, a Quasi-Persistent Scatterer based PSI approach has been applied using high-resolution TerraSAR-X interferometric data stack (10 images) to generate deformation time series and deformation velocity. Furthermore, results obtained from the applied PSI approach and ground-based observations (using GNSS) have shown good agreement with each other, in the order of ?5.20?mm/year (LOS) and ?5.38?mm/year (subsiding), respectively.     

Validation of performance of real-time kinematic PPP. A possible tool for deformation monitoring

Structural failures (bridge or building collapses) and geohazards (landslides, ground subsidence or earthquakes) are worldwide problems that often lead to significant economic and loss of life. Monitoring the deformation of both natural phenomena and man-made structures is a major key to assessing structural dynamic responses. Actually, this monitoring process is under real-time demand for developing warning and alert systems.One of the most used techniques for real-time deformation monitoring is the Global Navigation Satellite System (GNSS) real-time procedure, where the relative positioning approach, using a well-known reference station, has been applied.This study was conducted to evaluate the actual quality of the real-time kinematic Precise Point Positioning (PPP) GNSS solution for deformation monitoring, where it can be concluded that a promise tool is under development and should be taken into account on actual and near future real-time deformation monitoring studies and applications.     

浅谈福州GNSS基准站网建设

本文主要介绍福州市GNSS综合服务系统的建设。阐述基准站建设的总体构架、主要功能,以及有关技术简析。     

面向飞行器交会对接应用的载波相位差分技术研究

GNSS引导两飞行器交会对接的前提是实时可靠地估计相位模糊度。针对卫星和飞行器的高动态性所引发的频繁换星问题,提出一种实时递归相位模糊度估计方法。该算法能够有效处理失锁所造成的卫星起落现象,同时充分利用历史观测与当前观测方程中部分模糊度分量的关联性,使得模糊度估计的成功率对可见卫星数目的减少不敏感。为了验证该算法在空间飞行器对接中的精度和成功率,采用GPS模拟器仿真两飞行器近程导引段和最终逼近段的过程,应用新算法实时估计两飞行器间相对位置,精度达到亚厘米级水平,成功率在可见星数递减时依然渐进逼近100%。     

基于CORS的高层建筑物三维形变监测关键技术研究

主要研究了相对定位数学模型和数据预处理方法,分析了GNSS观测的主要误差源及处理办法,建立了Kalman滤波的实时参数估计方法和模糊度固定解算技术;研究了基于Kalman滤波的形变信息提取技术,建立了Kalman滤波平滑降噪数学模型,对基于不同平滑降噪因子的平滑效果进行了分析;以天津悦雅国际某高层建筑监测项目为例,结合天津市二等水准成果和天津CORS站点稳定性分析成果,验证基于CORS的高层建筑物三维形变监测方法的正确性。     

卫星导航系统基四选星算法

随着卫星导航系统的发展,可见星数大大增多,为了减少接收机运算量,需选择可见卫星的一个子类。本文分析了卫星导航系统中N个4星最优分布与某4星最优分布中的k(k≤3)个卫星(共4N+k颗卫星)的联合分布GDOP值,并以此为基础提出了一类低复杂度近似最优的基四选星算法。该算法以经典的4星选择算法(最大体积法和四步选择法)为基础,通过多次迭代与部分执行,实现任意多于4星的卫星选择。仿真结果表明该算法与准优算法相比运算复杂度和GDOP值都更低。     

GNSS信号接收机的构件初识──GNSS导航信号的收发问题之十

GNSS信号接收机是GNSS导航卫星的用户设备,是实现GNSS卫星导航定位的终端仪器。它是一种能够接收、跟踪、变换和测量GNSS卫星导航定位信号的无线电接收设备,既具有常用无线电接收设备的共性,又具有捕获、跟踪和处理弱达3.5E-16W~2.5E-17W卫星微弱信号的特性。为此,GNSS信号接收机的构件必须满足这种捕获、跟踪和测量GNSS信号的需求。     

定位定向接收机校准技术研究

介绍了全球导航卫星系统的组成与应用,利用本实验室的短基线场,对定位定向接收机进行实际大地坐标的定位与定向校准实验。给出了实验原理、实验过程及实验结果;并通过仿真机产生标准信号对接收机进行校准实验,对两种校准实验结果进行比较,分析了影响因素。     

基于GNSS技术的排土场边坡监测及稳定性研究

本文介绍了边坡工程监测技术和方法,并以大孤山铁矿废弃排土场边坡监测项目为例,运用GNSS在线监测技术,综合分析边坡变形监测数据,对大孤山排土场边坡的安全状态及稳定性进行评价。研究表明:①大孤山铁矿废弃排土场边坡各监测区域内沉降位移普遍要大于水平位移,且沉降位移的波动趋势显著高于水平位移,可知大孤山排土场边坡变形主要由沉降导致;②各监测区域的沉降位移曲线在2017年7～9月及2017年12月～2018年2月波动显著,呈现先下降后上升的趋势,与监测区域受夏季降雨影响处于活跃期以及冬季冰雪冻胀影响的情况相符,其中,降雨对监测区域变形的影响大于冰雪冻胀的影响;③球团厂、黄岭子村以及滑坡区监测区域的下部变形普遍大于上部变形,邻近滑坡区的尾矿库监测点水平位移及沉降位移要略高于尾矿库其他监测点,由于边坡底部紧邻厂区或居民生活区,应重点关注边坡底部变形,加强监测力度,确保该区域边坡稳定及安全;④综合分析可知,大孤山铁矿废弃排土场边坡划分的四个监测区域中,球团厂变形最大,黄岭子村及滑坡区次之,尾矿库稳定性良好。研究成果对同类矿山边坡工程的监测及预警具有重要借鉴意义。