共查询到20条相似文献，搜索用时 46 毫秒
1.
针对双星姿态测量中整周模糊度解算这一关键问题,提出了一种新的双星整周模糊度解算方法--天线反转法.其基本思想是,在静态初始化过程中将副天线绕主天线反转了180°.模拟算例表明,该方法能够快速可靠地解算出双星整周模糊度. 相似文献
2.
长距离网络RTK是实现GPS/BDS高精度实时定位的主要手段之一,其核心是长距离参考站网GPS/BDS整周模糊度的快速准确确定。本文提出了一种长距离GPS/BDS参考站网载波相位整周模糊度解算方法,首先利用GPS双频观测数据计算和确定宽巷整周模糊度,同时利用BDS的B2、B3频率观测值确定超宽巷整周模糊度。然后建立GPS载波相位整周模糊度和大气延迟误差的参数估计模型,附加双差宽巷整周模糊度的约束,解算双差载波相位整周模糊度,并建立参考站网大气延迟误差的空间相关模型。根据B2、B3频率的超宽巷整周模糊度建立包含大气误差参数的载波相位整周模糊度解算模型,利用大气延迟误差空间相关模型约束BDS双差载波相位整周模糊度的解算。克服了传统的使用无电离层组合值解算整周模糊度的不利影响。采用实测长距离CORS网GPS、BDS多频观测数据进行算法验证,试验结果证明该方法可实现长距离参考站网GPS/BDS载波相位整周模糊度的准确固定。 相似文献
3.
GPS双天线定向系统及优化模糊度搜索算法 总被引：2，自引：0，他引：2
研究了GPS载波相位双差测量方向的原理和应用最小二乘法解算基线矢量的方法;提出了快速解算整周模糊度的优化算法.实验表明,采用基线长度作为约束条件,应用GPS双天线测量方向的原理和搜索模糊度优化算法正确,其定向精度达0.12°,解算时间小于0.3s. 相似文献
4.
提出一种用于整周模糊度OTF求解的整数白化滤波改进算法。该算法首先对整周模糊度的协方差矩阵进行整数白化滤波处理 ,以降低整周模糊度间的相关性 ,然后构造搜索空间来判定是否需要进行搜索。如果需要 ,则通过搜索来确定变换后的整周模糊度 ;如果不需要 ,则通过直接取整来确定整周模糊度 ,进而得到原始的整周模糊度和基线分量的固定解。初步试验结果显示 ,采用改进方法解算整周模糊度可以提高成功率和解算效率 相似文献
5.
为解决DUFCOM方法单历元解算GPS双差整周模糊度因观测卫星数多导致解算效率低而影响GPS高频数据实时动态解算这一问题,同时考虑到DC算法解算效率高的优点,对观测卫星进行筛选分级处理,提出了一种快速确定算法。算例表明,该算法可避免在应用DUFCOM方法中二级卫星对一级卫星双差整周模糊度解算效率的影响,使得GPS单历元确定双差整周模糊度的效率显著提高,达到了GPS高频数据实时动态解算的目的。 相似文献
6.
GPS短基线整周模糊度的直接解法 总被引：5，自引：2，他引：3
提出了在位移值较大的情况下(0.7 m),通过多种载波相位组合,解算短基线GPS整周模糊度的方法。导出了在解算过程中保证L1和L2载波的整周模糊度N1和N2为整数的条件,从而将DC(direct calcu-lation)算法[1]不仅推广到大变形的情况,而且推广到短基线GPS整周模糊度的解算,解决了快速准确解算短基线GPS整周模糊度的问题。 相似文献
7.
整周模糊度的正确求解关系到GPS精密定位结果的正确性,搜索法解算整周模糊度的原则是获得目标函数的整数解作为模糊度参数的解,文中分析了各种不同搜索方法构造搜索空间的特性,比较了不同搜索方法对模糊度解算可靠性的影响,即通过搜索,不同的方法能否获得满足目标函数的一组整数解. 相似文献
8.
提出了一种长距离网络RTK参考站间双差整周模糊度快速解算方法,该方法利用双频载波相位模糊度间的线性关系确定宽巷模糊度,然后选取双频载波相位的备选模糊度组合,通过计算参考站间对流层误差和轨道误差等非色散误差,对双频载波相位整周模糊度进行搜索。实验结果表明,此方法能够快速、可靠地解算长距离参考站间的双差整周模糊度。 相似文献
9.
基于搜索空间构造模糊度搜索方法的可靠性 总被引：2，自引：0，他引：2
整周模糊度的正确求解关系到GPS精密定位结果的正确性，搜索法解算整周模糊度的原则是获得目标函数的整数解作为模糊度参数的解，文中分析了各种不同搜索方法构造搜索空间的特性，比较了不同搜索方法对模糊度解算可靠性的影响，即通过搜索，不同的方法能否获得满足目标函数的一组整数解。 相似文献
10.
北斗卫星导航系统双差网络RTK方法 总被引：1，自引：1，他引：0
针对北斗卫星导航系统常规实时动态差分(RTK)定位中,整周模糊度的快速解算和流动站位置信息的解算精度问题,该文研究了一种北斗卫星导航系统双频双差网络RTK方法,首先解算参考站网B1、B2载波相位整周模糊度,利用固定的参考站网载波相位整周模糊度计算参考站的观测误差,使用区域误差内插法计算流动站的综合误差影响,改正流动站的观测误差并进行流动站的整周模糊度解算,最后使用实测数据进行算法实验。实验结果表明,该文的方法可以利用北斗卫星导航系统双频观测数据实现网络RTK流动站的厘米级定位。 相似文献
11.
采用Landsat TM数据分析了阿克苏河—塔里木河断面水质污染状况,通过波段的DN值和常规监测数据建立能反映水质状况的
污染物监测模型。结果发现,将2000年常规监测数据代入模型后,与遥感数据的结果基本吻合| 重建阿克苏河—塔里木河的连续水体
污染变化曲线,得出污染物浓度随着远离上游而增加。 相似文献
12.
Monitoring drought dynamics in the Aravalli region (India) using different indices based on ground and remote sensing data 总被引：5，自引：0，他引：5
C. Bhuiyan R.P. Singh F.N. Kogan 《International Journal of Applied Earth Observation and Geoinformation》2006,8(4):289-302
The hard-rock hilly Aravalli terrain of Rajasthan province of India suffers with frequent drought due to poor and delayed monsoon, abnormally high summer-temperature and insufficient water resources. In the present study, detailed analysis of meteorological and hydrological data of the Aravalli region has been carried out for the years 1984–2003. Standardised Precipitation Index (SPI) has been used to quantify the precipitation deficit. Standardised Water-Level Index (SWI) has been developed to assess ground-water recharge-deficit. Vegetative drought indices like Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) and Vegetation Health Index (VHI) have been computed using NDVI values obtained from Global Vegetation Index (GVI) and thermal channel data of NOAA AVHRR satellite. Detailed analyses of spatial and temporal drought dynamics during monsoon and non-monsoon seasons have been carried out through drought index maps generated in Geographic Information Systems (GIS) environment. Analysis and interpretation of these maps reveal that negative SPI anomalies not always correspond to drought. In the Aravalli region, aquifer-stress shifts its position time to time, and in certain pockets it is more frequent. In comparison to hydrological stress, vegetative stress in the Aravalli region is found to be slower to begin but quicker to withdraw. 相似文献
13.
Piyoosh Rautela Ramesh Chandra Lakhera 《International Journal of Applied Earth Observation and Geoinformation》2000,2(3-4)
The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies. 相似文献
14.
ZHAN F. Benjamin 《地球空间信息科学学报》2011,(1)
Although it is well known that coseismic gravity changes take place during an earthquake, previous research has not yielded convincing evidence demonstrating that significant gravity changes occur before large earthquakes. Furthermore, even if we suspect that gravity changes occur before large earthquakes, we have yet to demonstrate how to consistently observe these changes for useful earthquake forecast that would bring benefits to society. We analyzed ground gravity survey data obtained in 1998, 2000, 200... 相似文献
15.
GNSS系统及其技术的发展研究 总被引：3，自引：1，他引：2
阐述了国际上卫星导航系统的总体发展,对美、俄、欧、中的四大全球系统,以及相关的区域系统和增强系统进行了简单的介绍,研究分析了GNSS系统及其技术的发展趋势,同时分析了我国Compass全球系统面临的机遇和挑战,并提出了我国未来工作的建议. 相似文献
16.
“4D”技术及其应用 总被引：13，自引：0，他引：13
介绍“４Ｄ”（即数字地面模型、数字正射影像、数字栅格地图和数字线划地图）系列产品的生产流程、关键技术、及其在耕地保护、防灾减灾救灾和城市规划等方面的应用方法。 相似文献
17.
《International Journal of Digital Earth》2013,6(1):66-87
Abstract Virtual Australia is not a well-defined or agreed concept. This discussion paper conceptualises Virtual Australia as a ‘virtual [digital] model containing and representing all non-trivial objects and their contextual environment – from blue sky to bedrock – in real world Australia’. It describes a scenario for Virtual Australia, one or two decades from now, in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a ‘Supranet’. It then examines the concept of the ‘Supranet’ – a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real time – and develops and discusses three principal characteristics of the Supranet: the ability to have or collect specific information (know); the ability to process information (think); and the ability to communicate that information. If, in the near future, any or all non-trivial devices are to some extent able to know, think and communicate, the potential for object autonomy will be realised. 相似文献
18.
Toward seamless indoor-outdoor applications: Developing stakeholder-oriented location-based services
Kohei OGAWA Edward VERBREE Sisi ZLATANOVA Naohiko KOHTAKE Yoshiaki OHKAMI 《地球空间信息科学学报》2011,14(2):109-118
Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders. 相似文献
19.
20.
地理数据库的关系模型及其实现 总被引：1，自引：0，他引：1
本文从以图论观点分析地理实体入手,系统阐述了地理数据库关系模型的设计法和过程。作者于1984年4～9月间在微型机上设计建立了关系型地理数据库的实方验系统(RGDB)。该系统采用了本文提出的关系模型,采用了可动态扩库的子库组合结构,这种结构具有灵活性和提高空间利用率的优点。RGDB含有多种功能的数据操作命令,除了具有一般检索功能外,还能进行“开窗”选取和十分“自由”的映象选取。本文对RGDB系统的主要性能和实现途径作了扼要介绍。 相似文献