逐次最小二乘在高精度曲面建模方法（HASM）中的应用

从高精度曲面建模方法（HASM）曲面方程出发,结合数据平差理论,建立了基于独立单元的计算模型,并且采用逐次最小二乘法对计算方程进行分组求解。对HASM-AD和几种经典方法的精度进行了交叉验证,结果表明,该算法模拟误差的均方根差远小于其他空间插值方法。     

支持向量机的北京城市热岛模拟:热岛强度空间格局曲面模拟及其应用

将支持向量机(SVM)曲面拟合算法引入城市热岛强度曲面模拟研究,以MODIS的地表温度产品(LST)数据为例,对2006～2008年北京地区城市热岛强度进行支持向量机(SVM)曲面拟合.敏感性分析和精度评价表明该算法精度较高,能够用来表征城市热岛的空间格局特征.应用结果表明,凭借该算法可对地表城市热岛制图.在年内和年际...     

三维激光扫描数据获取高分辨率DTM试验研究

三维激光扫描技术能够提供实体表面点云数据,可用于获取高精度高分辨率数字地形模型。本文以重庆万州区付家岩滑坡体为例探讨了采用三维激光扫描监测技术获取数字地形模型的方法,着重讨论了相关点云数据处理流程和关键技术问题。通过结合差分GPS技术进行激光数据的相对定位和绝对定位、去噪、拼接等方法,获得了该区域地表高精度地形数据,并生成了相应的数字高程模型。试验结果初步说明该技术可用于获取小尺度高精度高分辨率数字地形模型,具有一定的应用前景。     

深空探测器同波束相位参考成图相对定位方法

针对我国后续深空探测任务中高精度相对定位需求,提出了采用天文同波束相位参考成图技术进行深空探测器相对定位的方法。首先建立适用于深空探测器信号特点的同波束相位参考成图相对定位模型,然后分析信号带宽和UV覆盖两个因素对测量精度的影响。最后利用我国VLBI观测网(CVN)在2013年15、20和21日接收的嫦娥三号着陆器和玉兔号巡视器下行同波束数据,处理得到了巡视器在5个环拍点相对着陆器的位置,验证了本文方法的可行性及其对探测器下行信号的强适应性。与视觉定位结果的对比表明,巡视器相对着陆器定位精度达到米级。     

Effects of jpeg 2000 compression on automated dsm extraction: evidence from aerial photographs

This paper evaluates the effects of JPEG 2000 compression on automated digital surface model (DSM) extraction, using the area-based matching technique. Two stereopairs of aerial photographs, which have different photo scale, pixel size, and topographic type, are used as the images for the experiments. In the experiments, the DSM generated from the uncompressed image is set as the reference, and the elevation accuracy is computed for a range of compression ratios (2:1 to 100:1). The results show that the employed indices of image quality based on the JPEG 2000 compression are clearly superior to the commonly used JPEG compression technique—especially for high compression ratios. However, the elevation accuracy varies with the compression ratios. Also, JPEG 2000 compression does not have a significant influence on the percentage of the successful matching rate. In addition, a near linear fall-off is observed in extracted DSM accuracy with increasing compression ratios.     

地球表层建模研究进展

本文在讨论地球表层概念和地球表层建模定义的基础上,总结分析了地球表面形态表达、地球气候系统模拟、生态系统空间模拟分析和地球表层模拟系统等主要研究进展。分析结果表明,误差问题、多尺度问题、地球表层模拟速度问题和三维实时可视化问题是地球表层建模面临的主要挑战。为了解决这些问题,必须发展和采用诸如以遥感数据为初始场、以地面实测数据为优化控制条件的高精度高速度曲面建模新方法和新思路。     

矿区地表形变PPP监测自适应滤波算法及其应用

矿区地表易发生开裂、移动、塌陷等灾害,对矿区人文及生态环境造成巨大破坏。因此,针对矿区地表的监测研究意义重大。然而,常规的监测数据解算方法精度依赖于先验模型参数的准确性,若模型参数不准确,则解算精度难以满足监测需求。鉴于此,本文提出了基于PPP的矿区地表形变监测自适应滤波算法,并利用矿区工程数据进行试验,验证了算法的优越性。结果表明,本文算法能有效地控制动态模型参数偏差的影响,提高监测数据解算的稳定性,相比传统滤波算法,能够有效提高解算精度。     

A Study of the Local Geometric Accuracy of Count de Ferraris's Carte de cabinet (1770s) Using Differential Distortion Analysis

The eighteenth century Carte de cabinet of count de Ferraris is the first large-scale (1:11?520) topographic map of the entire Belgian territory, making it a valuable source of historical information. In the past, a number of studies have tried to assess the geometric accuracy of this map, but they all suffer from restricted technical capabilities for computing and visualizing the distortions, and most of them only focus on a limited number of the 275 map sheets. This paper therefore seeks to provide the first systematic and in-depth investigation of the map’s local geometric accuracy. Recently, two Belgian government agencies georeferenced the Flemish and Walloon part of the Carte de cabinet with a high level of detail, using some 30,000 ground control points to link the old map to the modern topographic map of Belgium. These data sets represent a new and unprecedented potential source of accuracy information. However, the high number of control points and our desire to compute distortions in an exact, local, quantitative and continuous way meant prominent techniques for studying the geometric accuracy of old maps, such as displacement vectors, distortion grids, triangular nets and the popular MapAnalyst software, were unsuited for this task. To meet all our requirements a new technique called Differential Distortion Analysis, which is influenced by the treatment of distortions in map projection theory, was used instead. Its advantages, structure and application to the Carte de cabinet are discussed in detail. The new technique allows calculating and displaying the map’s local angular and surface distortions with a very high spatial resolution. Consequently, it was possible to identify trends in the obtained levels of accuracy and to relate these to historical facts about the Carte de cabinet’s production process. This has resulted in important new insights into the map’s geometric accuracy.     

PSInSAR技术在地面沉降监测中的应用研究

永久散射体合成孔径雷达测量技术(PSInSAR)具有全天候、大范围、高精度监测地表形变的优点,是形变灾害监测领域一种新的经济的空间对地观测新技术。本文介绍了PSInSAR技术,并使用我国某地区的卫星SAR影像数据,运用PSInSAR技术完成了地面沉降监测的相关处理流程,并将结果与常规水准测量的结果进行了对比,证实了PSInSAR技术用于大范围地面沉降监测的有效性。     

基于混合光谱分解的城市不透水面分布估算

城市化的一个重要表现就是不透水面分布比率的上升,城市内部不透水面分布是城市生态环境的一个重要指标。对于规模较大的大城市,采用高性价比的中等分辨率影像,获取不透水面的分布,是当前国际研究的一个热点。本研究利用Landsat 7的ETM 影像,在线性光谱分解的技术上,提取了上海市的不透水面分布并对其空间特征进行了分析。研究揭示,ETM 影像对于城市尺度的信息提取,其成本是较低的;对于城市地域来说,利用植被、高反照度、低反照度和裸露的土壤四种最终光谱端元的线性组合,可以较好地模拟ETM 波谱特征,而除了水面以外的高反照度、低反照度两种最终光谱端元,可以较好地表达城市不透水表面信息。结果显示,利用中等分辨率影像对上海中心城区不透水面分布提取的精度还是令人满意的,总体上,上海市不透水面分布比率较高,不透水面分布的空间差异进一步揭示了城市土地覆被空间结构以及城市空间扩展的差异性。     

A high accuracy surface modeling method based on GPU accelerated multi‐grid method

A high accuracy surface modeling method (HASM) has been developed to provide a solution to many surface modeling problems such as DEM construction, surface estimation and spatial prediction. Although HASM is able to model surfaces with a higher accuracy, its low computing speed limits its popularity in constructing large scale surfaces. Hence, the research described in this article aims to improve the computing efficiency of HASM with a graphic processor unit (GPU) accelerated multi‐grid method (HASM‐GMG). HASM‐GMG was tested with two types of surfaces: a Gauss synthetic surface and a real‐world example. Results indicate that HASM‐GMG can gain significant speedups compared with CPU‐based HASM without acceleration on GPU. Moreover, both the accuracy and speed of HASM‐GMG are superior to the classical interpolation methods including Kriging, Spline and IDW.     

无人机遥感在大型不可移动文物三维重建中的应用

针对大型不可移动文物三维重建技术存在的困难,本文基于无人机遥感等平台,利用基于图片的三维重建技术,设计了一种低成本、简便高效、较高精度的大型不可移动文物的表面精细几何纹理获取与三维重建的技术流程,对建模中的技术问题进行了研究,并对其精度和实用性进行了评价。其结果较好地满足了文物测量的精度要求;为文物保护与展示等研究提供了新的思路,能全方位、近距离面向公众做三维展示;结果带有精确的地理位置信息,可作为三维GIS平台新的数据采集方法和数据源。     

VRS技术原理及网络RTK在城市规划测量中的应用

哈尔滨市GNSS双星导航系统正式建成并投入使用,其网络RTK的基本原理是通过虚拟参考站(VRS)技术进行超短基线的实时差分GPS测量,进而获得较高精度位置信息.系统网络RTK覆盖面积达1.4万km<'2>,和传统RTK测量技术相比较,网络RTK有覆盖范围广、精度高、易于操作等优点,在城市规划测量中得到了广泛的应用.     

An Adaptive Method of High Accuracy Surface Modeling and Its Application to Simulating Elevation Surfaces

An adaptive method is employed to speed up computation of high accuracy surface modeling (HASM), for which an error indicator and an error estimator are developed. Root mean‐square error (RMSE) is used as the error estimator that is formulated as a function of gully density and grid cell size. The error indicator is developed on the basis of error surfaces for different spatial resolutions, which are interpolated in terms of the absolute errors calculated at sampled points while paying attention to the landform characteristics. The error surfaces indicate the magnitude and distribution of errors in each step of adaptive refinement and make spatial changes to the errors in the simulation process visualized. The adaptive method of high accuracy surface modeling (HASM‐AM) is applied to simulating elevation surface of the Dong‐Zhi tableland with 27.24 million pixels at a spatial resolution of 10 m × 10 m. Test results show that HASM‐AM has greatly speeded up computation by avoiding unnecessary calculations and saving memory. In addition, HASM‐AM improves simulation accuracy.     

基于ASTER GED产品的地表发射率估算

地表发射率是地表温度反演的重要输入参数,为了解决现有地表发射率估算方法在裸露地表精度较差的问题,本文基于最新的ASTER全球地表发射率产品(ASTER GED)和基于植被覆盖度的方法(VCM),提出了一个改进的地表发射率估算方法。首先,利用ASTER GED产品求解裸土发射率,然后,利用ASTER波谱库中的植被发射率和植被覆盖度结合VCM方法计算地表发射率。利用张掖地区2012年11景ASTER TES算法反演的地表发射率产品和实测地表发射率数据进行了验证,同时利用一景Landsat 8 TIRS数据分析了对地表温度反演精度的影响。结果表明该方法估算的地表发射率整体精度较高,可以有效改进裸露地表的发射率估算精度,用于支持利用多种热红外传感器数据生产高精度的地表温度产品。     

船载水岸一体测量技术在码头改造工程中新应用

深圳港妈湾港区海星码头1#~4#泊位旧码头拆除工程实施过程中,为了防止在原码头深底层保留桩柱对新建桩柱的影响,需要对原码头桩柱泥面以下位置进行精密测量。本文采用船载综合测量系统水上水下一体化测量技术对妈湾港1#~4#泊位桩柱进行了水岸一体化高精度测量,通过利用激光扫描仪和多波束分别测量出水上、水下桩柱引水面点云图。基于高精度水面点云绝对坐标对水上、水下桩柱引水面点云进行特征拼接,从而获得桩柱引水面高精度绝对位置。然后根据引水面绝对位置和桩柱尺寸精准计算出保留桩柱泥面以下部分的点位和斜率。经过外符合精度验证,桩柱定位的绝对精度为10 cm。最后,将旧桩柱测量结果与新桩柱设计结果对比,结果表明：新旧桩柱在2#泊位存在一个桩柱发生碰撞,4#泊位存在10根桩柱新旧桩柱水平间隔小于10 cm,在施工过程中可能会发生碰撞。     

Using pan-sharpened high resolution satellite data to improve impervious surfaces estimation

Impervious surface is an important environmental and socio-economic indicator for numerous urban studies. While a large number of researches have been conducted to estimate the area and distribution of impervious surface from satellite data, the accuracy for impervious surface estimation (ISE) is insufficient due to high diversity of urban land cover types. This study evaluated the use of panchromatic (PAN) data in very high resolution satellite image for improving the accuracy of ISE by various pan-sharpening approaches, with a further comprehensive analysis of its scale effects. Three benchmark pan-sharpening approaches, Gram-Schmidt (GS), PANSHARP and principal component analysis (PCA) were applied to WorldView-2 in three spots of Hong Kong. The on-screen digitization were carried out based on Google Map and the results were viewed as referenced impervious surfaces. The referenced impervious surfaces and the ISE results were then re-scaled to various spatial resolutions to obtain the percentage of impervious surfaces. The correlation coefficient (CC) and root mean square error (RMSE) were adopted as the quantitative indicator to assess the accuracy. The accuracy differences between three research areas were further illustrated by the average local variance (ALV) which was used for landscape pattern analysis. The experimental results suggested that 1) three research regions have various landscape patterns; 2) ISE accuracy extracted from pan-sharpened data was better than ISE from original multispectral (MS) data; and 3) this improvement has a noticeable scale effects with various resolutions. The improvement was reduced slightly as the resolution became coarser.     

北京城市不透水层覆盖度遥感估算

 应用线性光谱混合模型研究城市环境生物物理组成，端元的确定是其关键。城市地表同物异谱现象显著，光谱变异强烈，对于高反照率地物尤其突出。端元的光谱变异对线性光谱混合模型拟合结果产生重要影响。以同种纯净地物光谱曲线形状具有相似性为出发点，提出了一种端元优化选取方法，在此基础上计算了北京城市地表不透水层覆盖度。研究结果表明，该方法能够在一定程度上减小端元光谱变异性对线性光谱混合模型拟合结果的影响，进而提高城市不透水层覆盖度的估算精度。     

黄河三角洲Sentinel-3高精度时空连续海陆表面温度反演

海陆表面温度是理解全球变化与人类活动的关键参数。针对已有温度反演产品海陆边界时空不连续的问题,本文采用Sentinel-3海陆表面温度辐射计(SLSTR)光学与热红外影像,通过植被指数阈值法逐像元计算陆表与海表发射率,基于分裂窗算法反演得到黄河三角洲陆海表面时空连续温度产品。结合地面温度观测和欧洲中期天气预报中心提供的全球中等分辨率数值大气再分析产品,验证了本文陆海温度产品(均方根误差优于1.1K)反演精度高于现有公开的全球产品,可为全球时空连续温度产品反演提供参考。