共查询到20条相似文献，搜索用时 187 毫秒
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郑正勰 《测绘与空间地理信息》2011,34(5):156-158
分析了尤溪县基础测绘控制网的现状,结合目前GPS空间定位技术、水准测量技术、区域似大地水准精化技术等多种大地测量技术手段,提出建立尤溪县基础测绘控制网和似大地水准面模型的必要性及应用前景,研究探讨了建立尤溪县基础测绘控制网和似大地水准面模型的内容方法和过程。 相似文献
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利用GPS定位技术结合准噶尔盆地区域内的重力资料、水准资料、高分辨率的地形数据以及最新的重力场模型,精确研究并确定准噶尔盆地的似大地水准面模型,以求取不同地区、不同位置高精度的高程异常值,从根本上解决GPS定位技术无法直接提供正常高的问题。 相似文献
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本文介绍了银川市利用GPS卫星定位技术进行基础控制网改造、二等水准网的建立及似大地水准面模型的确定,通过项目的实施实现了用GPS测量手段代替三角/导线测量和低精度的水准测量,充分发挥了GPS高精度、低成本、快速、灵活等特点,大幅度减少了外业工作量与生产成本,加快了构建“数字银川”地理空间基础框架的步伐,充分发挥了测绘在银川市经济建设与人民生活中的基础和先行作用。 相似文献
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全国及部分省市地区高精度、高分辨率大地水准面的研究及其实施 总被引：9，自引：1，他引：9
结合我国重力和地形资料及国内外较优的重力场模型，研制了适合我国重力场特征的360阶重力场模型WDM94，建立了中国新一代包括全部陆海国土的dm级（似）大地水准面CQG2000，建立了中国以GPS／水准为基础的高程异常控制网，利用海洋卫星测高数据进行我国海洋大地水准面的计算、我国陆地重力（似）大地水准面的研制厦我国陆海（似）大地水准面的拼接；研制了江苏省、海南省、深圳市、大连市、南京市及南水北调西线工程具有cm级精度的省市地区（似）大地水准面模型；结合GPS技术和高精度（似）大地水准面模型，研制了GPS测图软硬件一体化系统。 相似文献
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城市道路的高精度提取可为城市三维表达、城市地形分析、城市建设规划、交通导航等提供数据基础和支撑。本文以合肥市局部城区为试验区,以开源路网、街景图像和遥感影像为数据源,在利用最大似然法进行初提取的基础上,通过空间分析、统计分析、几何量测、最小二乘拟合等方法进行粘连分割、缺失处理和交叉口细化等关键处理,构建了多源数据协同的城市道路提取方法,并对提取结果进行了精度评价和分析。试验结果表明,本文提出的城市道路提取方法优于最大似然和面向对象方法,提取总体精度为96.65%,Kappa系数为93.71%,道路宽度偏离标准差为0.03m,特别是对同物异谱、同谱异物及遮挡等造成的信息提取不全问题具有良好的改善效果。 相似文献
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Bevis公式在不同高度面的适用性以及基于近地大气温度的全球加权平均温度模型 总被引：1，自引：1，他引：0
加权平均温度(T_m)是全球卫星导航系统(GNSS)反演可降水量(PWV)过程中的关键参量。利用Bevis公式和地表温度可以方便地得到地表附近的高精度T_m估计值。然而,不少研究指出,Bevis公式在高海拔地区存在较大误差。本文对Bevis公式在不同高度面的适用性进行研究后发现,Bevis公式在海拔较低时精度较高,随着海拔升高,精度逐渐降低。为了解决Bevis公式在高海拔地区适用性较低的问题,本文对近地空间范围内(本文指0～10 km的高程范围)的T_m与大气温度的关系展开了研究,发现两者在全球范围内都拥有很高的相关性,由此本文构建了基于近地大气温度的全球加权平均温度模型。对模型的检验结果表明,该模型在近地空间范围内的任意高度面上都可以提供高精度的T_m估计值。 相似文献
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Masayoshi Oka 《Transactions in GIS》2011,15(1):109-123
This article demonstrates a way to model the urban microclimate using a combination of statistical analysis and a geographic information system (GIS). Field measurements of ambient temperature and relative humidity were collected in various urban settings at ground level over two surface materials and at two different times of the day. A panel autoregressive (PAR) model was created to conduct a regression analysis capable of accounting for the spatial autocorrelation. With the PAR analyses, selected urban street characteristics showed varying effects over the different surface materials and at different times of the day. The overall influences were consistent with previous findings. PAR models were then applied in GIS to create thermal prediction maps for the study area to determine the hot and cool spots. Since GIS is the most commonly used technology among a wide range of researchers and professionals, this article provides a means to improve the synthesis, integration, and sharing of information to understand the relationship between the heat‐vulnerable population and heat stress within the urban environment. This methodology will be useful in the effort to reduce the heat‐related morbidity and mortality, which are expected to increase with projected global warming. 相似文献
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载波相位测量在高精度导航信号监测接收数据处理中的应用 总被引：1，自引：0，他引：1
在GPS广域差分系统中,参考站需要进行高精度导航信号监测接收,并获得良好的伪距观测数据。载波相位测量由于其测量精度高且观测噪声小,因此在伪距观测数据处理方面,发挥了重要作用。介绍了载波相位测量在高精度导航监测接收的伪距观测数据处理方面的具体应用,提出了一种综合利用三频电离层残差和裁波相位变化率,来实时可靠地检验并修复周跳的方法。 相似文献
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Nobuaki Kubo 《GPS Solutions》2009,13(4):271-280
Instantaneous real-time kinematic (RTK) techniques are one approach to achieving real-time high-accuracy positioning. The
object of this paper is to show the advantage of adding velocity information to instantaneous RTK positioning. In this paper,
velocity from Doppler frequency measurements is used to help resolve integer ambiguities in the LAMBDA method. In urban areas,
pseudorange measurements can suffer from significant errors due to strong multipath, despite the use of advanced multipath-mitigation
techniques. However, Doppler frequency measurements do not deteriorate as much as pseudoranges, because the multipath error
on Doppler frequency measurements is only in the range of several centimeters. Our proposed method has been tested by both
static and moving users in sub-urban environments. Single-epoch ambiguity fixing performance was improved compared to conventional
ambiguity resolution without velocity information. 相似文献
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地基SAR(synthetic aperture radar)可实现高精度的小区域性连续形变监测。为研究其形变探测能力与精度,建立了一套精度验证平台和系统。在楼顶布设不同位置分布的角反射器,并采用步进平台控制角反射器模拟不同数值形变,形变角反射器与稳定点及楼顶表面构成小区域二维形变场,利用IBIS-L(image by interferometric system-landslides)系统完成形变监测与分析。实验结果表明,当角反射器发生毫米级形变时,地基干涉雷达IBIS-L系统形变探测平均精度为0.27 mm,而角反射器发生亚毫米级形变时,其形变探测平均精度为0.11 mm;该系统可以实现小区域性的亚毫米级形变探测,对于缓慢微小变化,其具有更好的形变探测能力与可靠性。 相似文献
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研究结合重庆市主城区2011-2017年高分辨率遥感影像和相关地形图、规划资料及交通专题资料信息等,提取城市路网和城市建设用地数据,基于GIS操作平台,采用空间核密度方法分析主城区城市路网时空演变特征,探索城市路网空间分布规律,以街道(镇)为研究单元分析城市道路与城市用地扩张之间的耦合关系,为合理规划交通道路布局,促进城市扩张与道路网络的协调发展提供了重要参考依据。结果表明,主城区城市路网分布具有空间不均衡性特征,路网演变有明显的方向性,以东西两翼带状区域变化为主,路网密度变化集中在低密度区。与城市用地扩张相关性研究中发现,城市路网是城市扩张的主要驱动力之一,路网中密度区域对城市扩张的驱动效应最明显。 相似文献
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Recent advances in thermal infrared remote sensing include the increased availability of airborne hyperspectral imagers (such as the Hyperspectral Thermal Emission Spectrometer, HyTES, or the Telops HyperCam and the Specim aisaOWL), and it is planned that an increased number spectral bands in the long-wave infrared (LWIR) region will soon be measured from space at reasonably high spatial resolution (by imagers such as HyspIRI). Detailed LWIR emissivity spectra are required to best interpret the observations from such systems. This includes the highly heterogeneous urban environment, whose construction materials are not yet particularly well represented in spectral libraries. Here, we present a new online spectral library of urban construction materials including LWIR emissivity spectra of 74 samples of impervious surfaces derived using measurements made by a portable Fourier Transform InfraRed (FTIR) spectrometer. FTIR emissivity measurements need to be carefully made, else they are prone to a series of errors relating to instrumental setup and radiometric calibration, which here relies on external blackbody sources. The performance of the laboratory-based emissivity measurement approach applied here, that in future can also be deployed in the field (e.g. to examine urban materials in situ), is evaluated herein. Our spectral library also contains matching short-wave (VIS–SWIR) reflectance spectra observed for each urban sample. This allows us to examine which characteristic (LWIR and) spectral signatures may in future best allow for the identification and discrimination of the various urban construction materials, that often overlap with respect to their chemical/mineralogical constituents. Hyperspectral or even strongly multi-spectral LWIR information appears especially useful, given that many urban materials are composed of minerals exhibiting notable reststrahlen/absorption effects in this spectral region. The final spectra and interpretations are included in the London Urban Micromet data Archive (LUMA; http://LondonClimate.info/LUMA/SLUM.html). 相似文献
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GPS Solutions - Carrier phase observations are required for high-accuracy positioning with Global Navigation Satellite Systems. This requires that the correct number of whole carrier cycles in each... 相似文献
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对于没有长期连续潮汐观测站和无精密潮汐模型的地区,研究高精度潮汐改正方法具有重要意义。给出了基于短时间序列重力观测数据的高精度潮汐改正方法,并利用全球动力学计划中TIGOConcepcion、Kamio-ka和Hsinchu三个台站的超导重力观测数据对该方法进行了试验分析。研究结果表明,利用一天或数天重力观测数据可建立高精度潮汐模型,其振幅因子和相位延迟解算精度分别优于0.01和0.5°,潮汐改正精度可以达到μGal量级,验证了该方法的正确性和有效性。本文方法为无精密潮汐模型区域的潮汐改正提供了新的途径。 相似文献