GNSS three carrier ambiguity resolution using ionosphere-reduced virtual signals   总被引：19，自引：8，他引：11  

Yanming Feng 《Journal of Geodesy》2008,82(12):847-862

This paper presents a general modeling strategy for ambiguity resolution (AR) and position estimation (PE) using three or more phase-based ranging signals from a global navigation satellite system (GNSS). The proposed strategy will identify three best “virtual” signals to allow for more reliable AR under certain observational conditions characterized by ionospheric and tropospheric delay variability, level of phase noise and orbit accuracy. The selected virtual signals suffer from minimal or relatively low ionospheric effects, and thus are known as ionosphere-reduced virtual signals. As a result, the ionospheric parameters in the geometry-based observational models can be eliminated for long baselines, typically those of length tens to hundreds of kilometres. The proposed modeling comprises three major steps. Step 1 is the geometry-free determination of the extra-widelane (EWL) formed between the two closest L-band carrier measurements, directly from the two corresponding code measurements. Step 2 forms the second EWL signal and resolves the integer ambiguity with a geometry-based estimator alone or together with the first EWL. This is followed by a procedure to correct for the first-order ionospheric delay using the two ambiguity-fixed widelane (WL) signals derived from the integer-fixed EWL signals. Step 3 finds an independent narrow-lane (NL) signal, which is used together with a refined WL to resolve NL ambiguity with geometry-based integer estimation and search algorithms. As a result, the above two AR processes performed with WL/NL and EWL/WL signals respectively, either in sequence or in parallel, can support real time kinematic (RTK) positioning over baselines of tens to hundreds of kilometres, thus enabling centimetre-to-decimentre positioning at the local, regional and even global scales in the future.  相似文献   

基于支持向量机的CBERS-02卫星影像信息提取   总被引：1，自引：0，他引：1  

温兴平  胡光道  杨晓峰 《测绘科学》2008,33(5)

CBERS卫星是由中国空间技术研究院与巴西空间研究院联合研制的地球资源遥感卫星,CBERS-02卫星数据总体质量比CBERS-01卫星有所提高,本文利用支持向量机方法对CBERS-02卫星影像信息进行提取。研究中首先用6S模式对影像进行大气校正,然后选择RBF为支持向量机方法的核函数,并用交叉验证方法得到影响RBF核函数的两个最佳参数值进行学习完成信息提取,最后将提取结果制作成矢量图。通过研究得出用大气校正后的数据进行信息提取分类精度有所提高;与最大似然法和最小距离法相比,支持向量机方法分类精度较高。通过将研究结果与ETM+影像进行比较得出,CBERS-02卫星影像精度能够满足应用需求并能代替TM/ETM+数据开展研究工作。  相似文献   

Low multipath antennas for GNSS-based attitude determination systems applied to high-altitude platforms   总被引：1，自引：1，他引：0  

Luigi Boccia  Pasquale Pace  Giandomenico Amendola  Giuseppe Di Massa 《GPS Solutions》2008,12(3):163-171

High-altitude platforms (HAPs) are a flexible and attractive technology for providing innovative wireless services. These aerial platforms can be successfully employed for mobile or broadband communications and for disaster monitoring or response. However, one of the open issues is whether HAP stations can provide reliable services without temporal outages owing to stratospheric winds that can cause positional and attitude instabilities thus affecting the communication system operation. To counteract this issue, one possible solution is to use reconfigurable antennas whose pointing direction can be adjusted depending on the platform spatial orientation. However, this would require real-time three-axial attitude data. As a possible solution, this paper will review the potential of GNSS-based attitude determination systems with reference to HAP stations. In particular, it will be shown how the use of a particular class of low multipath and lightweight antennas can provide a high degree of accuracy without altering the avionic ballast.  相似文献   

UKF算法及其在GPS卫星轨道短期预报中的应用     

郑作亚  陈永奇  卢秀山 《武汉大学学报(信息科学版)》2008,33(3):249-252

分析了GPS卫星预报星历,在比较分析EKF和UKF优缺点的基础上,将UKF引入GPS卫星轨道预报研究中.数值模拟和结果分析表明,UKF方法预报更稳定,能有效地提高轨道预报精度和稳定性.  相似文献   

多源遥感影像数据的融合方法探讨   总被引：1，自引：0，他引：1  

孔庆楠 《测绘与空间地理信息》2008,31(4)

在分析和总结多源遥感影像数据融合的基础上,探讨了多源遥感影像数据融合的层次、模型、结构及其特点.归纳总结了多源遥感影像数据融合方法,目的是提高多光谱影像分辨率的同时保持色调不变,从另一个角度理解为在已知低分辨率多光谱影像和高分辨率全色影像的基础上,模拟生成高分辨率多光谱影像.本文介绍了遥感影像融合技术,系统阐述了几种常见的遥感影像融合方法及其应用.  相似文献   

支持国产软件维护企业自身生存发展     

马维胜 《中国勘察设计》2008,(1):73-74

在选用国产CAD软件时,总结了设计软件影响企业稳定盈利的因素,进行综合分析和对比,制定相应的策略和方法,以积极的态度解决了国产CAD软件的应用问题。  相似文献   

利用Quickbird卫星遥感影像进行1∶10000比例尺基本地理信息数据更新的探讨     

于桂芹  关天昊 《测绘与空间地理信息》2008,(6)

作者探索利用已有的控制点成果及1∶10000地形图矢量数据、高分辨率Quickbird卫星遥感影像,针对国内各省近年更新过的1∶10000数字正射影像数据、1∶10000地形图数据进行再次更新的方法进行了探索。  相似文献   

震前卫星热红外环形应力场特征   总被引：6，自引：1，他引：5  

强祖基  姚清林  魏乐军  赵勇  郭坚峰  曾佐勋  谢红接 《地球学报》2008,29(4):486-494

本文包括两部分内容:①描述了1996年2月3日云南丽江Ms7.0级地震,震前几天的卫星热红外图像呈现圆形,它的NNW、NW、SN、及NE向的热旋扭面往S收敛。该地震地表破裂由一系列张扭性裂缝组成,呈左旋左列,水平位错不明显,垂直断距数厘米。垂直力对构造变动的作用较为明显;而丽江地震震源机制解破裂面II的走向NNE6o,倾向W,倾角44o,P轴方位为NNE3o、仰角75o,近于直立,综合热旋扭面展布、地震地表破裂特征及震源机制解,得出该旋扭椭圆为地幔外侧右旋上涌所造成;②菲律宾萨马岛Ms7.0～7.5强震群及青海共和Ms7.0地震前热应力环椭圆的推进路径。根据这一特征得出交变潮汐力的地球动力学解释。卫星热红外图像震前应力热场的方法是临震预测地震的有效方法,卫星热红外技术辅以震源机制解和地表破裂带力学分析是研究地球动力学有力工具。地球自转速度变化,交变潮汐力和地幔旋扭上涌力是地球动力学的主因。  相似文献   

QuickBird影像制作1：10000DOM方法探讨   总被引：1，自引：0，他引：1  

曹立  刘伟  周靖  翟黎明 《地理空间信息》2008,6(3):7-9

随着卫星遥感影像数据更加广泛地应用于测绘,针对QuickBird影像制作1：10000 DOM的方法,从正射纠正的三种不同方式进行了实验和探讨,分析了利用外业控制点或者在原有DRG、DOM上选取控制点制作DOM的方法、精度、工作量,总结提出了方便、快捷、实用的工作模式。  相似文献   

Commentary and critique of “accounting for mineral resources: Issues and BEA's initial estimates”     

DeVerle Harris  Michael Rieber 《Natural Resources Research》1996,5(1):7-21

The Bureau of Economic Analysis (BEA), U.S. Department of Commerce, in keeping with broad international efforts to green national gross domestic product (GDP) accounts, has attempted to create satellite accounts for mineral depletion. The present paper criticizes the BEA's unit rent measure of resource depletion, which is based upon Hotelling's pure theory of exhaustion. Following a thorough criticism of Hotelling's theory as a real-world model of mineral prices, practical issues related to the treatment of recycling, exploration, definition of reserves/resources, and their valuation/exploitation are introduced. For crude oil and natural gas and the nonfuel minerals, specific application problems of joint products and residuals complicate BEA's assumptions and efforts.  相似文献