恶劣环境下GPS/BDS混合双差模糊度固定性能分析     

杨东辉  徐爱功  隋心  张涵  陈玮娴 《测绘科学》2016,41(12):27-31

针对在恶劣观测环境下每个GNSS系统只观测到较少的几颗卫星,采用标准双差模型很难实现整周模糊度固定的问题,该文对GPS/BDS系统间混合双差模型进行研究,利用该模型计算出GPS/BDS系统偏差。在此基础上,利用实验分别对模拟和真实恶劣观测环境下的模糊度固定性能进行分析,实验结果表明,恶劣环境下GPS/BDS系统间混合双差模型表现良好,相较于经典的双差模型可将模糊度固定平均所需时间分别缩短43%和33%,模糊度固定成功率分别提高107%和31%。  相似文献   

倾斜摄影测量的城市真三维模型构建方法   总被引：3，自引：0，他引：3  

周晓敏  孟晓林  张雪萍  弥永宏 《测绘科学》2016,41(9):159-163

针对如何基于近年来新推出的倾斜摄影测量技术快速构建城市真三维模型的问题,在研究分析国内基于该技术构建三维模型方法的基础上,提出了利用Street Factory系统,结合少量人工干预快速构建城市真三维模型的方法。采用倾斜影像联合空中三角测量技术,实现了多角度倾斜影像的一体化区域网平差;通过多视影像密集匹配和自动纹理关联,实现了高精度真实三维模型的构建。基于RCD-30倾斜相机获取的西安大雁塔景区倾斜影像,开展城市真三维模型构建试验。结果表明,所提方法构建的城市真三维模型满足相关规范的要求,适合大规模区域城市三维模型快速构建,对测绘生产单位规模化生产具有一定的参考价值。  相似文献   

抗差估计的多波束测深数据内插方法   总被引：2，自引：0，他引：2  

张志伟  暴景阳  肖付民 《测绘科学》2016,41(10):14-18

针对传统多波束测深数据网格化内插方法抗差性不足的问题,该文将抗差估计理论应用于网格化内插方法中。基于不确定度指标建立了距离不确定度联合加权内插模型,在该模型的权函数中引入了等价权,同时给出了等价权设计方案及迭代初值确定原则,以增强模型的抗差性;介绍了一种节点邻域参考点合理选取方法,给出了改进内插法实现的基本步骤,最后通过实测数据对反距离加权法、联合加权法及改进方法内插水深质量进行比较。结果表明,改进方法内插结果要优于另外两种方法,可应用于多波束测深数据网格化处理中。  相似文献   

面向蓝藻的洱海气象监测站布局方法     

吴玉杰  卜方玲  陈莉琼  方新  付静 《测绘科学》2016,41(7):104-108,114

针对洱海流域蓝藻预警研究所需的气象数据不足的问题,提出洱海气象监测站优化布局方法,采用环境影响统计概念模型分析了对环境产生影响的主要经济因素,根据水体污染指标将洱海各个行政区分为高污染区和低污染区,再考虑汇入洱海支流是否流经高污染区,认为在高污染区支流汇入口是蓝藻发生概率较高的区域。依据2个主要参数:区域污染程度和支流入口,部署气象监测站,该监测站能为洱海蓝藻预警研究提供必要、准确和可靠的水面气温、降雨量以及日照长度等气象参数,将对水环境的监测和研究具有重大意义和广泛应用前景。  相似文献   

Use of an inside buffer method to extract the extent of urban areas from DMSP/OLS nighttime light data in North China     

Minghong Tan 《地理信息系统科学与遥感》2016,53(4):444-458

Defense Meteorological Satellite Program (DMSP)/Operational Linescan System (OLS) nighttime imagery provides a valuable data source for mapping urban areas. However, the spatial extents of large cities are often overestimated because of the effect of over-glow from nighttime light if a fixed thresholding technique is used. In the work reported here, an inside buffer method was developed to solve this issue. The method is based on the fact that the area overestimated is proportional to the extent of the lit area if a fixed threshold is used to extract urban areas in a region/county. Using this method, the extents of urban areas in North China were extracted and validated by interpretations from Landsat Thematic Mapper images. The results showed that the lit areas had a significant linear relationship with the urban areas for 120 representative cities in North China in 2000, with an R² value of over 0.95. This demonstrates that the inside buffer method can be used to extract urban areas. The validation results showed that the inside buffer model developed in 2000 can be directly used to extract the extent of urban areas using more recent nighttime light imagery. This is of great value for the timely updating of urban area databases in large regions or countries.  相似文献   

Modeling the risk of spread and establishment for Asian longhorned beetle (Anoplophora glabripennis) in Massachusetts from 2008-2009     

Andrew J. Shatz  Florencia Sangermano  Jennifer Miller  Arthur Elmes 《国际地球制图》2016,31(8):813-831

Land managers responsible for invasive species removal in the USA require tools to prevent the Asian longhorned beetle (Anoplophora glabripennis) (ALB) from decimating the maple-dominant hardwood forests of Massachusetts and New England. Species distribution models (SDMs) and spread models have been applied individually to predict the invasion distribution and rate of spread, but the combination of both models can increase the accuracy of predictions of species spread over time when habitat suitability is heterogeneous across landscapes. First, a SDM was fit to 2008 ALB presence-only locations. Then, a stratified spread model was generated to measure the probability of spread due to natural and human causes. Finally, the SDM and spread models were combined to evaluate the risk of ALB spread in Central Massachusetts in 2008–2009. The SDM predicted many urban locations in Central Massachusetts as having suitable environments for species establishment. The combined model shows the greatest risk of spread and establishment in suitable locations immediately surrounding the epicentre of the ALB outbreak in Northern Worcester with lower risk areas in suitable locations only accessible through long-range dispersal from access to human transportation networks. The risk map achieved an accuracy of 67% using 2009 ALB locations for model validation. This model framework can effectively provide risk managers with valuable information concerning the timing and spatial extent of spread/establishment risk of ALB and potential strategies needed for effective future risk management efforts.  相似文献   

Effect of sensor modelling methods on computation of 3-D coordinates from Cartosat-1 stereo data     

Mritunjay Kumar Singh  R.D. Gupta  Snehmani  Anshuman Bhardwaj  Ashwagosha Ganju 《国际地球制图》2016,31(5):506-526

The orbital and the rational polynomial coefficients (RPC) models are the two most commonly used models to compute a three-dimensional coordinates from an image stereo-pair. But it is still confusing that with the identical user provided inputs, which one of these two models provides more accurate digital elevation model (DEM), especially for mountainous terrain. This study aimed to find out the answer by evaluating the impact of used models on the vertical accuracy of DEM extracted from Cartosat-1 stereo data. We used high-accuracy photogrammetric DEM as the reference DEM. Apart from general variations in statistics, surprisingly in a few instances, both the DEMs provided contrasting results, thus proving the significance of this study. The computed root mean square errors and linear error at 90% (LE90) were lower in case of RPC DEM for various classes of slope, aspect and land cover, thus suggesting its better relative accuracy.  相似文献   

四川盆地回龙地区下侏罗统自流井组大安寨段混积岩特征及模式   总被引：1，自引：0，他引：1  

谭梦琪  刘自亮  沈芳  谢润成  刘成川  邓昆  徐浩 《沉积学报》2016,34(3):571-581

川西回龙地区自流井组大安寨段发育湖相碳酸盐岩和碎屑岩的混合沉积,结合野外露头、钻井岩芯、测井和显微组构等资料的综合分析,对该研究区混积岩沉积微相特征进行了精细刻画。研究认为,回龙地区大安寨段属湖泊混合沉积相,分为滨浅湖混合沉积和半深湖混合沉积两个亚相,并划分了五个沉积微相,分别为高能介壳滩混合沉积微相,低能介壳滩混合沉积微相,砂质浅滩混合沉积微相,浅湖混合沉积微相以及半深湖混合沉积微相。基于所划分的混合沉积相的特征和四川盆地以及研究区回龙大安寨段在侏罗纪的沉积相演变过程,分析了该区混积岩的成因及混合沉积演化模式。得出结论:研究区湖相混合沉积主要受物源供给和水动力条件的控制,在五种不同混合沉积微相控制作用下形成了不同类型的混积岩。  相似文献   

四川盆地早寒武世龙王庙期沉积特征与古地理   总被引：2，自引：1，他引：1  

马腾  谭秀成  李凌  曾伟  金民东  罗冰  洪海涛  胡平 《沉积学报》2016,34(1):33-48

基于盆内及其周缘钻孔取芯和露头剖面资料,结合区域背景和龙王庙组地层充填厚度分析认为,四川盆地周缘龙王庙期北邻摩天岭微古陆和汉南古陆、西接康滇古陆,东南和东北分别为威信-黔江、石阡-秀山-龙山和镇巴-巫溪-巴东水下古隆起环抱;盆内呈近北东向展布的川中古隆起和阆中-通江坳陷、江津-奉节坳陷构成“一隆两坳”,南部泸州-筠连-昭通继承性坳陷依然存在;盆地及周缘向东北隅和东南隅分别接入秦岭洋和江南盆地。受此影响,龙王庙期发育连陆碳酸盐岩台地-斜坡-盆地沉积体系,连陆碳酸盐岩台地构成沉积主体,可识别出混积潮坪、局限-蒸发台地、半局限-局限台地和台地边缘沉积相类型;进一步通过碎屑岩含量与陆源方向、石灰岩、白云岩和膏盐岩含量与海域局限性和台地边缘相对位置、颗粒岩含量等分析,阐明了龙王庙期岩相古地理展布样式并建立了沉积模式。结果表明潮坪向海侧、水下古隆起、泸州-筠连-昭通坳陷周缘是颗粒滩有利发育区,乐山和资阳地区经由早寒武世早期的充填拼合作用已形成统一古隆起,震旦纪末期-早寒武世的南北向桐梓-筠连裂陷槽演变为泸州-筠连-昭通台内坳陷,研究成果对拓宽龙王庙组滩控岩溶型储层的勘探领域具有重要的指导作用。  相似文献   

川中地区茅口组两期流体叠合控制下的白云石化模式     

王珏博  谷一凡  陶艳忠  强子同  强深涛  蒋婵 《沉积学报》2016,34(2):236-249

岩相学特征、地化分析揭示:川中地区下二叠统茅口组白云岩存在三种白云石:①平直晶面细晶白云石(δ13C_PDB=3.06‰,δ18O_PDB=-6.81‰;Fe:1×10-6,Mn:未检出,Sr:150×10-6);②非平直晶面粗晶鞍状白云石(δ13C_PDB=3.22‰,δ18O_PDB=-7.82‰;Fe:149×10-6,Mn:185×10-6,Sr:85×10-6);③非平直晶面细晶白云石(δ13C_PDB=3.49‰,δ18O_PDB=-9.45‰;Th=123℃,S=133~139‰NaCl;Fe:58×10-6,Mn:59×10-6,Sr:76×10-6)。研究结果表明存在两期白云石化流体:①早期压实作用形成的埋藏白云石化流体(T=37.4℃;S=29.8‰NaCl);②晚期受构造控制的热液白云石化流体(Th=114.8℃;S=153~226‰NaCl)。明确了三种白云石的成因:平直晶面细晶白云石是由早期埋藏流体交代泥晶基质形成的;非平直晶面细晶白云石是平直晶面细晶白云石在受到热液流体改造后所形成的;而非平直晶面粗晶鞍状白云石则是由热液流体直接沉淀出的。基于研究结果建立了相应的白云化模式。  相似文献