共查询到20条相似文献，搜索用时 656 毫秒
1.
为提高无人机对地定位精度，必须对系统进行几何标定与补偿。首先进行了直接地理定位实验，检验系统在不经过任何标定时的直接地理定位精度；然后进行了自由网光束法平差实验，以验证无地面控制点时系统的定位精度；最后进行了POS辅助自检校光束法平差，对内方位元素变化、相机畸变、IMU安置角进行标定和补偿，并验证了系统误差补偿后的直接地理定位精度。实验结果表明，未经几何标定的无人直升机直接地理定位的精度可满足应急条件下测绘保障要求；少量地面控制点的辅助下定位精度远优于1:500比例尺地形图测图的要求，可用于常规测绘生产；系统误差补偿后，直接地理定位精度有明显提升:平面精度提高46.37%，高程精度提高62.49%；系统误差标定和补偿方法正确、有效，无人直升机具有很好的测绘应用前景。 相似文献
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国产机载大视场三线阵CCD相机GNSS偏心矢量和IMU视轴偏心角标定技术 总被引：1，自引：0，他引：1
针对国内首台自主研制的机载三线阵CCD相机（以下简称GFXJ）,开展了国产GFXJ的GNSS偏心矢量和IMU视轴偏心角标定技术研究工作。首先介绍了GFXJ相机的成像特点,然后分析建立了GFXJ的GNSS偏心矢量标定模型和IMU视轴偏心角标定模型,并提出了GNSS偏心矢量和视轴偏心角循环两步法标定方案,最后在国家嵩山遥感综合实验场获得了多次飞行试验数据。通过进行区域网平差和标定处理,验证了本文建立的GNSS偏心矢量标定模型和IMU视轴偏心角标定模型的正确性和有效性,证实了本文提出的循环两步法标定方案可靠、可行,可显著提升GFXJ的几何定位精度。利用GNSS偏心矢量和IMU视轴偏心角标定值,大幅提高了GFXJ相机的无控定位精度。辅以少量控制点进行区域网平差,GFXJ影像平面定位精度可满足1：1000地形图测图的空中三角测量精度要求,高程精度距离指标要求略有差距。目前该款相机仍在校飞阶段,定型后几何性能有望进一步提高。同时,本文建立的GNSS偏心矢量标定模型和IMU视轴偏心角标定模型及提出的循环两步法标定方案,可为其他机载线阵CCD相机的标定处理提供借鉴。 相似文献
3.
基于机载POS系统定位定向原理,建立解算国产POS与数码相机集成系统偏心角、偏心分量的数学模型,经过POS、相机、惯性稳定平台等多传感器集成的航空摄影试验,分析系统误差检校和POS直接地理定位的精度,验证该检校模型的正确性与可行性。 相似文献
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车载三维数据采集系统的绝对标定及精度分析 总被引：1，自引：0，他引：1
针对GPS/INS/CCD相机集成的车载三维数据采集系统,给出了系统精确的直接定位方程,并将罗德里格矩阵用到系统的绝对标定中,推导了定位方程中所需的相机坐标系和惯导载体坐标系之间的平移与旋转参数的求解公式.然后,根据误差传播定律,推导了X、Y、Z三个方向上的坐标误差公式及点位误差公式.实验结果表明,本标定方法意义明确,计算过程简单,具有较高的标定精度,对实际应用具有重要的价值. 相似文献
6.
《测绘科学技术学报》2013,(5)
从直接定向技术的原理出发,分析了POS系统误差产生的原因,在此基础上建立了补偿POS位置、姿态测量误差的数学模型,并通过POS辅助多线阵影像光束法平差实现了对POS系统误差的一步法检校。ADS40数据的实验结果表明,检校IMU偏心角不需要控制点参与。引入同架次、同航高检校场的标定结果改正POS数据之后,POS辅助直接定位的精度可达1像元左右,接近常规光束法平差的水平。 相似文献
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针对海洋大地基准点位置标定的各项误差影响因素难以直接线性化为数学模型的问题，该文基于我国首个深海海底大地基准点的标校试验数据(水深3 000 m),利用公式推导结合数值方法定量分析了主要误差因素对海底定位精度的影响。声速误差对海底定位精度的影响很大，其中影响约为0.3 m的声速短周期时变误差难以消除；航迹几何结构对称性会对定位结果精度造成分米级影响；测船位置的系统偏差对海底定位结果具有等量级的影响(小于0.2 m);测船姿态的系统偏差在5°以内时影响小于0.4 m;观测值时标误差在0.5 s以内时影响为厘米级；时延测量值系统偏差小于0.1 ms时仅在垂向造成0.11 m的影响。为实现准确度优于2 m的海底绝对定位目标，测船航迹结构应保持对称，声速剖面精度应优于0.1 m/s,测船位置精度应优于0.1 m,时延观测值精度应优于0.1 ms,并对姿态测量安装角、杆臂矢量偏心值和观测数据时标偏差进行严格标定。 相似文献
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针对现有的相机标定方法无法适应计算能力较弱移动端设备的问题,该文提出一种改进的适用于移动端设备的相机快速标定方法,获取高精度的相机内、外参数。在传统相机标定方法的基础上,引入二阶径向畸变和二阶切向畸变建立带有非线性畸变项的相机模型,同时,借助非线性最小二乘的LM算法优化迭代初始估值参数,从而快速得到高精度相机内、外参数。实验表明,该方法提高了相机标定效率和精度,参数迭代耗时由0.220s缩短至0.063s(移动端耗时为0.234s),反投影误差由0.25pixel降低至0.15pixel以内。 相似文献
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以我国自行研制的机载三线阵CCD相机为例,对基于POS的三线阵影像定位的成像模型、内方位的几何标定、外方位元素的解算以及直接定位和区域网平差方法进行了理论与实验研究.实验结果表明,利用GPS/IMU数据与摄影测量观测值进行联合平差,可以有效地克服相机内、外方位元素的系统误差,提高定位精度. 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
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
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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
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
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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