共查询到20条相似文献,搜索用时 156 毫秒
1.
2.
两次SAR图像成像时卫星位置的差异导致即使在平坦地区InSAR干涉图上也会有参考面相位存在。由于定轨精度有限,InSAR数据处理过程中需去除轨道误差相位。目前常用的去除轨道误差的方法为基于轨道状态矢量计算出初始基线,再根据地面控制点信息,利用最小二乘算法得到精密基线;或将初始基线对应的参考面相位去除后,再对剩余相位进行快速傅里叶变换或曲面拟合,得到趋势性相位再去除。由于去除参考面相位在去除大气相位和获取形变相位之前,因而基线精密估计的过程中易受到大气相位和形变相位的影响,影响形变解算结果。在实际应用中发现存在干涉图在去除参考面相位后依然有趋势性相位的现象,本文针对此现象考虑大气相位和形变相位影响,提出了利用地面控制点相位残差定权的基线估计方法,提高了估计形变结果的精度,模拟试验和实际应用表明该方法具有一定的有效性和可行性。 相似文献
3.
4.
INSAR技术是最有潜力获取高精度DEM的手段之一。在其关键技术中,基线估计是影响最终DEM精度的一个关键因素。通常,较小的基线估计误差将会导致获取的DEM中存在较大的斜坡效应。但是,对于境外等难以获取地面控制点的区域,很难精确地估计出基线参数,从而使获取的DEM误差很大。针对这种情况,从INSAR的基本原理入手,提出了一种新的利用平地干涉相位进行初始基线估计的方法。利用1994年美国NASA航天飞机SIR-C/X-SAR数据和中国科学院电子所机载双天线干涉数据进行了实验,结果表明:该方法适用于无控制地区的基线估计,它无需地面控制点,并且估计出的基线参数比较精确。 相似文献
5.
利用平地干涉相位进行INSAR初始基线估计 总被引:6,自引:1,他引:6
INSAR技术是最有潜力获取高精度DEM的手段之一.在其关键技术中,基线估计是影响最终DEM精度的一个关键因素.通常,较小的基线估计误差将会导致获取的DEM中存在较大的斜坡效应.但是,对于境外等难以获取地面控制点的区域,很难精确地估计出基线参数,从而使获取的DEM误差很大.针对这种情况,从INSAR的基本原理入手,提出了一种新的利用平地干涉相位进行初始基线估计的方法.利用1994年美国NASA航天飞机SIR-C/X-SAR数据和中国科学院电子所机载双天线干涉数据进行了实验,结果表明:该方法适用于无控制地区的基线估计,它无需地面控制点,并且估计出的基线参数比较精确. 相似文献
6.
星载重轨干涉SAR卫星在高程测绘和形变测量中有着全天时全天候和大范围的优势,其中干涉基线是决定干涉性能的重要指标,而卫星重访轨道对干涉基线起着决定性的作用。通过对现有高分三号干涉数据轨道参数的分析,发现干涉基线相比国外先进卫星过长且稳定性有待提高。本文通过对相对轨道根数和机动控制的分析,得到满足重轨干涉SAR系统要求的稳定基线。以第一次观测的轨道为参考轨道,基于在摄动情况下重复观测轨道与参考轨道的相对轨道根数,计算得到重轨干涉基线的变化规律,并对不同纬度的观测目标进行了样例分析。在基线变化规律的基础上,利用机动速度和相对轨道根数的关系,进一步计算得到满足基线状态需求的机动控制方法。通过实际数据分析,给出了相对轨道根数变化对初始理想构型的影响,验证了重轨干涉基线变化规律符合本文的分析,并利用仿真样例给出了使得重轨干涉基线达到预期要求的机动控制方案。实际数据和仿真实验表明该模型能够通过可长时间观测并准确获得的轨道根数直接计算基线状态,并能从干涉基线需求出发,快速准确的得出对卫星的控制策略。 相似文献
7.
8.
准确有效去除干涉纹图中的平地相位是精确莺建DEM的关键.探讨了两类常见的去平地相位方法(基于地理定位和基于干涉频谱),分析了其所引起的误差影响.通过Envis砒和JERS-1两种数据的验证结果表明:在可获取精密轨道数据的情况下,基于地理定位的去平地方法能够有效去除干涉纹图中所包含的平地相位,并很好地控制最终所得的DEM误差,其效果优于基于干涉频谱的去平方法;基于干涉频谱的去平方法在干涉频谱平均空间频率为0时,所引起的DEM误差相对较小;在精密轨道数据缺乏的情况下,两种方法均不能满足重建DEM精度要求. 相似文献
9.
10.
针对传统的多项式模型去除InSAR轨道误差时,只能去除由于基线不准导致的平地相位残余误差,而对于基线误差引起的与高程相关的地形相位误差仍保留在干涉图中,提出了一种多分辨率分析的干涉相位轨道误差去除方法.从InSAR成像几何结构出发,分析轨道误差的空间特征,推导了由基线误差引起的平地相位误差及地形相位误差;再通过多分辨率分析把轨道误差与对流层延迟误差相位、外部DEM引起的地形误差相位、噪声相位等进行滤除,最后采用最小二乘计算多项式模型参数,可以更精细的估计出轨道误差相位,吸收与地形相关的误差.结果表明,经过改正的干涉图与DEM的相关系数仅0.033 8,相对于线性模型和二次多项式模型的0.165 5和0.071 9,对地形相关轨道误差的去除改善程度达到79.1%和53.0%,能够更好地去除轨道误差,提高了轨道误差估计精度,吸收了与地形相关的误差. 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.
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