基于ADS40影像的海岛测图控制点需求分析

主要以ADS40数码影像资料为基础,针对典型海岛测区的控制点布设,制定不同的布点方案,通过空中三角测量作业及平差实验,比较各种方案的数字空中三角测量成果精度,论证得出最佳、最优的外业布点方案,为海岛的外业控制点布设提供指导及依据.     

卫星遥感影像在海岛(礁)测图中的应用研究

利用卫星遥感影像进行大比例尺海岛(礁)测绘过程中,为解决独立无控岛屿立体测图和海岸线内业测量精度低以及海岸带不接边等技术问题,对在实际生产中应用的稀少控制区域网平差、海岸线潮位推算法和要素接边原则等关键技术进行了论述,并通过数据分析得出了技术应用的正确性,为今后利用高分辨率卫星遥感影像进行海洋测绘提供借鉴。     

南海岛礁航空摄影常见问题及对策

为解决远离大陆的海岛礁地形测绘的技术难题,在西沙群岛应用IMU/DGPS辅助海岛礁无控航空摄影技术进行了作业,经实测成果检验,影像精度满足大比例尺航测要求。基于试验分析,对在南海岛礁进行航空摄影常见问题提出了解决建议,有助于航空摄影测量技术在海岛礁测绘中的应用推广。     

海港工程浚后测量的实施

疏浚工程测量比例尺大,精度要求高,但规范较少。通过比较国标、行业规定对疏浚工程测量的技术要求,认为疏浚工程测量中要抓好技术设计、外业测量、数据处理、质量评定4个关键环节。外业数据采集阶段需要抓住水位控制、测量定位、深度测量、质量控制这4个重点方向,以获得可靠的测量数据信息,满足工程测量的高精度数据要求,提交高质量的测量成果资料。     

海洋测绘航空摄影测量体系建设思考

分析了航空摄影测量技术的发展和要求,结合海岸带、海岛礁测绘特点和需求,论述了海洋测绘航空摄影测量技术、装备、标准和人才体系建设的重点和方向,明确提出了技术和装备建设存在的问题、发展思路和技术方案,为海洋测绘航空摄影测量体系建设提供参考。     

海岛礁航空摄影测量技术应用研究

海岛礁地形测量是海洋测绘的重要内容,航空摄影测量是地形图测绘的主要手段。针对海岛礁测绘难点,提出了海岛礁航空摄影测量的关键技术和解决方案,通过海岛礁航空摄影、空中三角测量和重要地物测绘等技术方法分析,深化了海岛礁航空摄影测量应用理论基础。     

基于WorldView卫星影像的海岛测图精度控制分析

根据WorldView卫星影像的特点,分析其原始定位精度,并结合海岛测区的地形地貌特点,应用稀少控制卫星影像航天摄影测量平差方法,合理地进行控制点布设,同时有效控制外推岛屿的定位精度。对于独立海岛进行无控自由网平差,并量测一定数量的海岸水位点作为高程点,进行模型置平作业。通过比对实测瞬时水涯线,检查、检测其海岸线高程精度。最终保证数字空中三角测量的成果满足海岛(礁)测图卫星影像成图区的成果精度要求。     

水深测量误差成因分析

在海洋测量中特别是大比例尺海洋工程水深地形测量中,极易产生水深数据的误盖．根据作者的实践经验,分析了潮汐、风向、海浪和安装等因素对水深数据误差的影响,并提出在海洋测绘实施过程中应注意的问题及解决方法,以减少对测深数据精度的影响。     

海洋磁力测量测线布设间距的选取

基于海洋磁力测量特点,在对布设测线方向研究的基础上,对海洋磁力测量中布设测线间距的选取进行了研究,提出了选取布设测线间距的原则,给出了几种选取测线间距的方法,并对其可行性进行了验证。     

无人机的海岸地形航测技术探讨

根据海岸带的定义,说明其地形图测绘的内容及要求。分析了无人机航测系统中数码相机的检校内容,参照航空摄影测量规范和无人机航测外业实践,探讨了无人机进行海岸带地形测量的方法和步骤,对海岸带区域开展无人机航测作业具有一定的参考意义。     

浙江省领海基点海岛现状监测和分析

为及时掌握领海基点及其标志建设、领海基点海岛开发利用以及领海基点海岛周边海域生态环境等状况，文章采用卫星影像、无人机航摄和现场巡查相结合的监测方式，对浙江省领海基点海岛标志、地形地物、植被、地质灾害、人类活动、开发利用状况和周边海域生态环境进行监测和分析。研究结果表明：浙江省领海基点海岛保护状况总体较好，周边海域海水符合第一类和第二类海水水质标准，地形地貌无明显变化；部分领海基点海岛出现海蚀崖、海蚀沟和岩体裂缝并有海钓活动痕迹，部分领海基点方位点标志碑由于风暴浪的冲击存在局部损毁的现象。后续应对损毁领海基点方位点标志碑开展整修和维护工作；对已发生和可能发生的崩塌和滑坡等地质灾害进行常态化监测；在掌握海岛生态系统现状的基础上建立评估机制，开展海岛生态系统健康评估；积极与利益相关部门开展联系和沟通，形成领海基点海岛保护协调制度；进一步加强对领海基点海岛保护的宣传工作。     

大倾斜航空摄影图像地理坐标赋予方法

为了获取大倾斜航空摄影图像中目标点的位置,提出了参照基准图像,基于改进的6参数仿射变换模型进行几何纠正的方法。该方法对基准图像和大倾斜航空摄影图像分别进行角点检测,然后进行配对处理,配对后的相邻角点进行分组后,构建Delaunay三角网,在局部范围内分别进行仿射变换。实验表明,对大倾斜航空摄影图像赋予地理坐标能够达到较好的结果。     

海岸带及岛礁数字航空摄影传感器性能及选型研究

研究了当前国际上3种主流数字航空摄影传感器ADS40/80、DMC及UCXp,并分析三者的成像原理及关键技术,从多个方面进行评估和比较。针对海岸带及岛礁航空摄影的需求,对传感器的选型进行了研究,为获取满足海洋测绘指标要求的航空摄影数据源提供支持。     

基于多源数据的福建东山岛海岸侵蚀及其不同时空尺度成因分析

海岸侵蚀对海岛紧缺的陆地资源及旅游价值较大的沙滩危害巨大。基于卫星遥感、有人航空摄影、无人机航测、GPS和现场调查等多源数据,利用GIS分析了东山岛海岸线类型、位置与长度变化及滩面冲蚀演变。研究表明,东山岛多处曲折自然岸线转化为较为平直的人工岸线致使整体岸线长度减少,无人机高程反演满足滩面排水冲蚀监测精度要求,乌礁湾和山南湾不同养殖排水方式形成不同特征的滩面冲沟,改变了沙滩微地貌形态。海平面上升和台风风暴潮是长期趋势性和短期突发性侵蚀因素的代表,当前短时间尺度的人类活动已成为滩面冲蚀的最主要因素,且有可能转变为长期趋势性因素。     

基于无人机和无人船的岛礁地形测绘技术

无人岛礁及其周边环境复杂、基准不一,对其进行高精度测绘存在诸多困难。介绍了一种基于无人机和无人船的测绘系统,融合大地测量、无人机航空遥感、无人船水下测绘等多源观测技术获取无人岛礁一体化测绘成果。并在广东省珠海市的三角岛进行实地测量,获取了海岛水上水下一体的三维点云、等值线、DOM等数据,陆上成果精度达厘米级,水深测量成果符合相关规范要求,该成果可广泛应用于海洋、国土、测绘、规划、建设等领域,有助于解决无人岛礁缺乏控制点造成的数据精度低、各部门需求数据多次采集耗时费力等问题。实践证明该技术具有一定的工程意义。     

Remote and synoptic water-wave measurements by aerial photography: A model, experimental results, and an application

Aerial photography can be an important source of information regarding surface waves and oceanic features that affect the propagation of these waves. This correspondence briefly reviews the parameters involved in aerial photography of coherent trains of surface waves, including the effects of water reflectance, waves, and sun and cloud conditions, on wave imaging in aerial photos. It also describes an analytical model of the specular reflection of sunlight by surface waves, together with experimental results from an outdoor wave facility. Analytical expressions are derived for the accuracy of wavelength measurements using aerial photos of waves in the glitter pattern. Further, it treats wave slope determination from aerial photos of idealized waves and presents experimental results from an outdoor wave facility. The application of remote synoptic surface flow determination by imaging of surface waves is briefly discussed.     

利用2012年中国北极考察现场观测数据和卫星遥感资料评估海洋2号卫星扫描辐射计数据反演北极海冰密集度的研究

A retrieval algorithm of arctic sea ice concentration(SIC) based on the brightness temperature data of "HY-2" scanning microwave radiometer has been constructed. The tie points of the brightness temperature were selected based on the statistical analysis of a polarization gradient ratio and a spectral gradient ratio over open water(OW), first-year ice(FYI), and multiyear ice(MYI) in arctic. The thresholds from two weather filters were used to reduce atmospheric effects over the open ocean. SIC retrievals from the "HY-2" radiometer data for idealized OW, FYI, and MYI agreed well with theoretical values. The 2012 annual SIC was calculated and compared with two reference operational products from the National Snow and Ice Data Center(NSIDC) and the University of Bremen. The total ice-covered area yielded by the "HY-2" SIC was consistent with the results from the reference products. The assessment of SIC with the aerial photography from the fifth Chinese national arctic research expedition(CHINARE) and six synthetic aperture radar(SAR) images from the National Ice Service was carried out. The "HY-2" SIC product was 16% higher than the values derived from the aerial photography in the central arctic. The root-mean-square(RMS) values of SIC between "HY-2" and SAR were comparable with those between the reference products and SAR, varying from 8.57% to 12.34%. The "HY-2" SIC is a promising product that can be used for operational services.     

中国第四次北极科学考察期间北极点附近海冰和融池的航空遥感观测

An aerial photography has been used to provide validation data on sea ice near the North Pole where most polar orbiting satellites cannot cover. This kind of data can also be used as a supplement for missing data and for reducing the uncertainty of data interpolation. The aerial photos are analyzed near the North Pole collected during the Chinese national arctic research expedition in the summer of 2010(CHINARE2010). The result shows that the average fraction of open water increases from the ice camp at approximately 87°N to the North Pole, resulting in the decrease in the sea ice. The average sea ice concentration is only 62.0% for the two flights(16 and 19 August 2010). The average albedo(0.42) estimated from the area ratios among snow-covered ice,melt pond and water is slightly lower than the 0.49 of HOTRAX 2005. The data on 19 August 2010 shows that the albedo decreases from the ice camp at approximately 87°N to the North Pole, primarily due to the decrease in the fraction of snow-covered ice and the increase in fractions of melt-pond and open-water. The ice concentration from the aerial photos and AMSR-E(The Advanced Microwave Scanning Radiometer-Earth Observing System) images at 87.0°–87.5°N exhibits similar spatial patterns, although the AMSR-E concentration is approximately 18.0%(on average) higher than aerial photos. This can be attributed to the 6.25 km resolution of AMSR-E, which cannot separate melt ponds/submerged ice from ice and cannot detect the small leads between floes. Thus, the aerial photos would play an important role in providing high-resolution independent estimates of the ice concentration and the fraction of melt pond cover to validate and/or supplement space-borne remote sensing products near the North Pole.