机载POS系统对地定位方法初探   总被引：16，自引：4，他引：16  

郭大海  吴立新  王建超  郑雄伟 《国土资源遥感》2004,15(2):26-31

高精度定位定向系统(Position&;OrientationSystem,简称POS系统)能够获取机载传感器的空间位置和三轴姿态信息,从而定量化反演遥感信息获取过程,实现机载遥感直接对地定位(DirectGeoreferencing)。本文首先介绍POS与航空摄影系统的集成方法与工作原理;然后初步分析了POS系统的主要误差来源,在此基础上,研究了POS系统数据处理及误差控制方法;最后,结合河南安阳飞行试验数据的分析处理结果,进行了精度和可行性分析。  相似文献   

基于非线性平差模型的坐标转换公式   总被引：4，自引：2，他引：4  

包欢 付子傲陈刚  王玉京 《测绘学院学报》2004,21(3):175-177

用线性近似法以及非线性参数估计法讨论了直角坐标系七参数转换模型，指出改进的Gauss-Newton方法具有理论严密、计算简洁、易于编程、精度较高等持点。对于处理类似坐标转换的非线性模型具有重要的理论和实践意义。  相似文献   

无地面控制GPS辅助光束法区域网平差   总被引：2，自引：4，他引：2  

袁修孝  朱武  武军郦  王瑞幺 《武汉大学学报(信息科学版)》2004,29(10):852-857

介绍了在WGS-84坐标系中进行GPS辅助光束法区域网平差的基本原理以及利用大地水准面拟合方法实施大地高与正常高的变换方法。利用新疆库尔勒地区1：25000和1：50000实际航摄资料验证了理论与程序实现的正确性。试验结果表明，无地面控制GPS辅助光束法区域网平差可用于中小比例尺测图的加密，在WGS-84坐标系中可以获得较高的点定位精度，而在国家80坐标系下，利用大地水；隹面拟合前后的GPS摄站坐标进行GPS辅助光束法区域网平差，加密精度没有明显差异。  相似文献   

Channel geometry of mountain streams in New Zealand     

Ellen E. Wohl  Andrew Wilcox 《Journal of Hydrology》2005,300(1-4):252-266

A dataset of 21 study reaches in the Porter and Kowai rivers (eastern side of the South Island), and 13 study reaches in Camp Creek and adjacent catchments (western side of the South Island) was used to examine downstream hydraulic geometry of mountain streams in New Zealand. Streams in the eastern and western regions both exhibit well-developed downstream hydraulic geometry, as indicated by strong correlations between channel top width, bankfull depth, mean velocity, and bankfull discharge. Exponents for the hydraulic geometry relations are similar to average values for rivers worldwide. Factors such as colluvial sediment input to the channels, colluvial processes along the channels, tectonic uplift, and discontinuous bedrock exposure along the channels might be expected to complicate adjustment of channel geometry to downstream increases in discharge. The presence of well-developed downstream hydraulic geometry relations despite these complicating factors is interpreted to indicate that the ratio of hydraulic driving forces to substrate resisting forces is sufficiently large to permit channel adjustment to relatively frequent discharges.  相似文献   

Time-domain approach to linearized rotational response of a three-dimensional viscoelastic earth model induced by glacial-isostatic adjustment: I. Inertia-tensor perturbations     

Zden&#;k Martinec  Jan Hagedoorn 《Geophysical Journal International》2005,163(2):443-462

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云南沿边境地带生态环境3S监测、 评价与调控研究   总被引：8，自引：0，他引：8  

齐清文  何大明  邹秀萍  姜莉莉  李晋 《地理科学进展》2005,24(2):1-12

本文利用全球新千年整体生态系统评估的理论，以云南省沿边境地带生态系统变化跨境生态安全为研究对象，探寻并揭示我国陆疆系统的跨境生态系统变化监测、评价和生态安全综合调控的基础理论与信息机理；进而研究基于“3S”云南沿边境地带的生态环境监测、评价与综合调控的方法和关键技术，包括方法和技术体系的建立、指标体系的建立、多尺度效应和尺度转换、数学模型的建立、综合调控模式和决策方案的建立等；在案例研究部分，建立了背景数据库，然后选择大、中、小尺度进行了全区生态环境现状评价，重点河道、典型路段和重点口岸的影响评价和预测预报研究，最后进行了综合调控模式和方案的探讨，并对研究结果进行了动态仿真和虚拟表达研究。  相似文献   

Late Quaternary sea‐level change and evolution of Belfast Lough,Northern Ireland: new offshore evidence and implications for sea‐level reconstruction     

Ruth M. K. Plets  S. Louise Callard  J. Andrew G. Cooper  Joseph T. Kelley  Daniel F. Belknap  Robin J. Edwards  Antony J. Long  Rory J. Quinn  Derek W. T. Jackson 《第四纪科学杂志》2019,34(4-5):285-298

The interplay of eustatic and isostatic factors causes complex relative sea‐level (RSL) histories, particularly in paraglacial settings. In this context the past record of RSL is important in understanding ice‐sheet history, earth rheology and resulting glacio‐isostatic adjustment. Field data to develop sea‐level reconstructions are often limited to shallow depths and uncertainty exists as to the veracity of modelled sea‐level curves. We use seismic stratigraphy, 39 vibrocores and 26 radiocarbon dates to investigate the deglacial history of Belfast Lough, Northern Ireland, and reconstruct past RSL. A typical sequence of till, glacimarine and Holocene sediments is preserved. Two sea‐level lowstands (both max. ?40 m) are recorded at c. 13.5 and 11.5k cal a bp . Each is followed by a rapid transgression and subsequent periods of RSL stability. The first transgression coincides temporally with a late stage of Meltwater Pulse 1a and the RSL stability occurred between c. 13.0 and c. 12.2k cal a bp (Younger Dryas). The second still/slowstand occurred between c. 10.3 and c. 11.5k cal a bp . Our data provide constraints on the direction and timing of RSL change during deglaciation. Application of the Depth of Closure concept adds an error term to sea‐level reconstructions based on seismic stratigraphic reconstructions.  相似文献   

Daily salinity fluctuation alleviates salt stress on seedlings of the mangrove Bruguiera gymnorhiza     

Wenqing Wang  Li Xu  Siyang You  Chao Liu  Mao Wang 《水文研究》2020,34(11):2466-2476

Salinity is a vital factor that regulates leaf photosynthesis and growth of mangroves, and it frequently undergoes large seasonal and daily fluctuations creating a range of environments – oligohaline to hyperhaline. Here, we examined the hypotheses that mangroves benefit opportunistically from low salinity resulting from daily fluctuations and as such, mangroves under daily fluctuating salinity (FS) grow better than those under constant salinity (CS) conditions. We compared growth, salt accumulation, gas exchange, and chlorophyll fluorescence of leaves of mangrove Bruguiera gymnorhiza seedlings growing in freshwater (FW), CS (15 practical salinity units, PSU), and daily FS (0–30 PSU, average of 4.8 PSU) conditions. The traits of FS-treated leaves were measured in seedlings under 15 PSU. FS-treated seedlings had greater leaf biomass than those in other treatment groups. Moreover, leaf photosynthetic rate, capacity to regulate photoelectron uptake/transfer, and leaf succulence were significantly higher in FS than in CS treatment. However, leaf water-use efficiency showed the opposite trend. In addition to higher concentrations of Na⁺ and Cl⁻, FS-treated leaves accumulated more Ca²⁺ and K⁺. We concluded that daily FS can enhance water absorption, photosynthesis, and growth of leaves, as well as alter plant biomass allocation patterns, thereby positively affecting B. gymnorhiza. Mangroves that experience daily FS may increase their adaptability by reducing salt build-up and water deficits when their roots are temporally subjected to low salinity or FW and by absorbing sufficient amounts of Na⁺ and Cl⁻ for osmotic adjustment when their roots are subsequently exposed to saline water.  相似文献   

基于Matlab的GPS网间接平差教学设计与实现     

陶秋香  翟敏 《测绘与空间地理信息》2016,(3):9-12

GPS网间接平差是测绘类本科专业误差理论与测量平差基础教学的重要组成部分。本文针对GPS网间接平差存在的观测数据多、计算量大、在实际课堂教学中很难讲解清楚等问题,提出基于Matlab的GPS网间接平差教学设计与实现方法。给出GPS网间接平差课堂教学的内容及难点,阐述基于Matlab的GPS网间接平差程序设计流程及关键步骤的实现方法。结合3个具体的GPS网平差实例,展示程序运行的结果。结果表明,基于Matlab进行GPS网间接平差教学既有助于加深学生对GPS网间接平差理论知识的理解,培养学生理论联系实际的能力,又可以实现学生所学计算机高级编程语言与专业知识的有机结合,提高学生的编程能力和学习兴趣。  相似文献   

Matlab在矿区GPS网间接平差中的应用     

朱晓红  王鹏 《测绘与空间地理信息》2016,(12)

针对矿区GPS网间接平差,首先,详细地分析了GPS网间接平差原理,按一定格式将GPS网中的观测数据编制成观测文件,其次,按观测文件的格式编制算法将数据读入并存储,然后用间接平差原理处理得到平差结果,最后绘制网形和误差椭圆并生成平差报告,为矿区控制网的建立和矿区生产管理提供了便利。实验验证了本文程序的实用性。  相似文献