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提出了一种利用动基线求解卫星无线电测定业务RDSS(Radio Determination Satellite Service)定向技术中单差整周模糊度的方法.接收机首先在基线处于某一初始状态下测量两颗卫星的载波相位单差,然后旋转基线两个较小角度,并分别测量不同状态下两颗卫星的载波相位单差.通过两次旋转获得的各基线状态之间的关系获得旋转平面,进而求得初始状态下的基线矢量.将求得的基线矢量初值代入单差观测方程可求得整周模糊度.整周模糊度的求解精度与基线长度、基线初始状态方位角以及基线转角等多种因素有关.仿真分析表明,当基线长度为3 m,基线两次旋转角度分别为30°,基线初始状态方位角在(0°,120°)和(180°,300°)范围内时,都可以正确求解整周模糊度. 相似文献
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设计了一种短基线情况下双差模糊度的实时解算方法,利用双频载波相位的两个长波组合φ-3,4和φ4,-5,通过坐标初始值约束和双频信号之间的相关关系,可快速求解模糊度,采用抗差自适应滤波来提高模糊度求解的可靠性及定位精度。该方法对监测点初始点位误差的要求可放宽至50cm,适合于变形幅度较大的动态监测系统。 相似文献
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北斗二代系统伪距码中存在与高度角相关的系统性偏差,该偏差会影响高精度的数据处理。基于Melbourne-Wübbena(MW)组合,分别利用现有的伪距码偏差改正模型和实测基线的双差宽巷模糊度残差,分析了伪距码偏差对基线解算的影响。理论分析表明,随着基线长度的增加,伪距码偏差对MW组合确定双差宽巷模糊度的影响越来越大,对300 km基线的影响可达0.36周。实际算例表明,无论基线长短,地球同步轨道(geostationary earth orbit,GEO)卫星的双差宽巷模糊度残差中始终存在偏差;而对于倾斜地球同步轨道(inclined geostationary orbit,IGSO)和中轨(medium earth orbit,MEO)卫星而言,当基线小于300 km时,双差基本可以消除伪距码偏差,其双差宽巷模糊度固定率基本和GPS一致,但当基线超过300 km时,部分卫星的双差宽巷模糊度残差就会存在明显偏差,其双差宽巷模糊度固定率也较低,此时需考虑伪距码偏差的影响。 相似文献
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基于北斗三频的短基线单历元模糊度固定 总被引:2,自引:0,他引:2
采用三频观测值能组成更多波长更长、噪声较小的观测值;通过依次固定超宽巷、宽巷、窄巷模糊度,可以实现模糊度的快速固定。目前以TCAR、CIR为代表的方法均是基于无几何模型的方法,通过伪距直接求解相位模糊度;由于不同卫星模糊度各自单独求解,没有综合利用所有卫星的观测值信息。基于有几何模型,使用LAMBDA方法进行逐级模糊度固定,依次固定超宽巷、两个宽巷、两个无电离层组合窄巷模糊度,最后使用模糊度固定的两个无电离层组合进行最终基线解算。北斗实测数据验证表明,针对10km的短基线数据,采用本文方法可以实现100%的单历元模糊度固定的成功率。 相似文献
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针对不存在先验信息时常规GPS单历元数据处理中存在的问题,提出了一种新的GPS整周模糊度单历元算法.该算法先采用一个历元的码观测值进行最小二乘定位,求取初始模糊度,并根据解的中误差来构造模糊度原始搜索空间,再采用两种不同线性组合的扩波方法进行模糊度变换,使原模糊度的搜索空间变小.在模糊度的新搜索空间确定后,通过线性组合的逆变换求取模糊度N1及N2,并以模糊度函数法进行真值的搜索,实现单历元解算.采用基线长度不同的两组数据测试,结果表明了本文方法的可行性和可靠性. 相似文献
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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
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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
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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
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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
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“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
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《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
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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