小型无人机航测在农田信息监测中的应用研究

近年来,数字化科学技术迅猛发展,数字化中国也在强有力推进中,数字产业化、产业数字化、数字化治理和数据价值化进一步深化。加之大疆、南方等多款小型无人机航测操控性、简便性和稳定性日趋成熟,机载传感设备具备了多功能、多样性、高精度和轻便性等特点,这成为了小型无人机航测在农田信息监测高效实时采集的基础。小型无人机航测的数据采集技术具有精度高、时效性强和操作成本低等特点,因而,小型无人机航测被应用于农田信息数据采集和监测。本文基于小型无人机航测技术,实现了农田信息数字化监测,为数字化农业和乡村振兴提供了有力的技术支撑。     

基于无人机数字航摄系统的快速测绘

应实时化测绘的需求,无人机航摄近年来发展迅猛,本文介绍了以无人机为平台的数字航摄系统的性能与特点,以及利用该系统进行航测作业的技术流程,并介绍了利用该系统实施的1∶2000航测试验实践,试验证明了该系统的可行性与适用性,且特别适合于小区域应急测绘数据的获取与更新。     

基于微型无人机航测的三维地形辅助测量方法研究

为了实现对三维地形的辅助准确测量,提出基于微型无人机航测的三维地形辅助测量方法.采用地形网格间距的自适应网格匹配方法构建三维地形微型无人机航测遥感图像采集模型,对采集的三维地形微型无人机航测遥感图像采用匹配滤波器实现自适应滤波检测,提取遥感图像的高精度地形特征量,通过三维地形数据加载和程序交叉编译控制方法,实现对三维地...     

基于SoC的无人机航测视频信息叠加设计与实现

采用无人机航测平台标校光学助降系统光学下滑道指示角度时,需要确定无人机航拍穿越光学下滑道时刻航测相机镜头成像中心位置。首先需要获取无人机标校平台航测相机视频帧成像瞬时的精确时间,然后根据成像时刻GPS天线相位中心的坐标,结合无人机平台的姿态信息通过坐标转换得到拍照时刻航测相机镜头几何中心的坐标。本文设计并实现了一种基于SoC的无人机航测视频信息叠加方法,充分利用SoC内的嵌入式ARM核和媒体处理平台资源,ARM核心处理器的主要功能是完成与外设的通信及控制,专用的媒体处理平台完成音视频解码,采用SoC专用解码芯片的方案具有开发灵活和集成度高等优点。     

顾及入射角的全波形激光雷达数据校正方法

相比于传统激光雷达,全波形激光雷达以非常小的采样间隔记录激光回波的全部信息并以数字化存储,经过处理可以得到能够反映地物固有特性的潜在特征。在全波形激光雷达回波数据处理中,对波形数据的校正是波形分解和地物目标特征提取的关键步骤。针对激光雷达系统获取数据过程中同类型建筑物目标对不同入射方向激光反射的差异,提出了一种全波形激光雷达数据的后向散射截面校正方法,建立了顾及入射角的波形数据校正模型。采用机载小光斑全波形激光雷达数据对提出的校正方法进行验证,结果表明:该校正方法能够对同类型建筑物目标的波形数据的后向散射截面进行归一化校正,消除不同入射角对该类目标后向散射截面的影响,极大提高后续建筑物目标精细分类和特征提取等应用的精度。     

基于BIM模型的结构设计审查方法研究

建筑信息模型(BIM)作为建筑工程的数字化表达,正在成为实现建筑全生命期信息化、工业化和 智能化的重要手段。以 BIM 模型作为设计交付成果是未来建筑设计领域发展趋势。然而,现阶段建筑结构设 计的审查工作还是以人工手动审查为主,普遍存在主观、效率偏低且易出差错等问题。因此,以框架结构模型 审查为实例,通过关系数据库方法解析 BIM 模型数据,采用 Java 编程转译结构设计规范条文,提出一种基于 BIM 模型的结构设计审查方法。实现过程包括：①模型准备与信息映射;② 规范条款分类和转译;③ 建立连 接和代码执行。结果表明：该方法可以部分实现结构模型的自动化审查,提高了设计审查工作的科学性、可靠 性和规范性,为今后全面实现设计审查的自动化和智能化提供了技术基础和参考方法。     

全波形地面激光雷达波形数据分解研究

随着激光雷达技术的快速发展,地面激光雷达系统也逐渐具备了全波形数据获取能力,因此开展波形分解研究对于推动全波形地面激光雷达的发展及应用极为迫切。本论文拟采用高斯拟合算法开展地面激光雷达全波形数据分解,该方法首先采用阈值迭代法对高斯模型特征参数进行预估并准确估算出各波形高斯分量,最后通过LM （Levenberg-Marquardt）优化算法对特征参数进行优化,实现全波形地面激光雷达数据分解。     

基于迭代最近点的井下无人机实时位姿估计

针对煤矿井下无GPS信号、低照度、结构化环境等特点,提出了一种基于迭代最近点(ICP)的井下无人机实时位姿估计方法。通过建立四旋翼无人机运动模型与机载激光雷达观测模型,将煤矿井下四旋翼无人机位姿估计问题转换为机载激光点云数据的扫描匹配问题。用三维激光雷达作为四旋翼无人机机载环境测量传感器,得到无人机当前位姿下的观测点云数据;以第1帧位置为初始位,通过ICP方法得到连续2帧点云数据之间的相对变换矩阵,迭代求解连续关键帧点云数据,得到煤矿井下四旋翼无人机实时位姿估计结果。采用滤波与下采样方法对点云数据进行优化,加速变换矩阵的求解,满足四旋翼无人机位姿估计实时性需求。实验结果表明,基于ICP的井下无人机实时位姿估计方法能够快速、有效地求解四旋翼无人机位姿,相比于正态分布变换方法,ICP方法更适用于煤矿井下四旋翼无人机的实时位姿估计。     

基于滚动速度障碍法的无人机山地航测避障路径规划研究

无人机在进行山地航测时,经常遭遇鸟类等动态障碍,若不能及时规避掉障碍,极容易发生坠机事故。为此,研究一种基于滚动速度障碍法的无人机山地航测避障路径规划方法。基于山地环境模型,结合飞行路径长度、路径平滑度建立一个综合目标函数并利用改进布谷鸟搜索算法求解,得到无人机山地航测的初始路径。对图像进行预处理后,识别无人机初始路径飞行过程中遇到的障碍物,并通过超声波测量无人机与障碍物之间的距离,以此建立速度障碍模型,实现速度障碍碰撞分析,通过滚动窗口的方式确定无人机与障碍物是否存在飞行冲突。基于滚动速度障碍避障方法实现滚动角度避障和速度避障,获取最终的优化路径,完成基于滚动速度障碍法的无人机山地航测避障路径规划。测试结果表明:航测避障路径长度为571.45m,平滑度为165.52,规划的方案更具合理性。     

搭载POS数据的无人机影像提高定位精度的方法

针对无人机航测依赖原始POS数据成像地理目标定位的精度较低问题,提出了一种建立误差模型纠正POS数据用于无人机成像的方法。鉴于原始POS数据存在系统误差,通过分析其误差来源,并根据奇、偶行带间影像外方位线元素误差具有相反性,建立POS数据纠正模型;利用误差改正数对原始机载POS数据进行纠正,并用改正后POS数据进行影像坐标定位精度对比。实验结果表明,纠正后的POS数据减小了系统误差,可以快速、有效地提高无人机影像地理坐标定位精度。     

基于空间形态数据的铁路通信数字工程设计系统

建筑信息模型 (building information modeling, BIM)技术作为建筑业实现信息化数字化转型的核心技术, 在铁路建设全生命周期中具有很高的研究价值. 在铁路通信机械室内、站场、区间设计中, 将铁路通信实体的空间位置、形状、大小、关系等空间形态描述数据化, 结合铁路通信设计规范、相关铁路BIM标准以及专业实际设计需求, 研究开发出铁路通信数字工程设计系统. 本系统以空间形态数据为支撑, 铁路工程实体结构分解标准为基础, 在三维环境下实现了铁路通信机械室内机柜设备的智能布设, 站场通信沟槽线缆的路径规划, 区间通信信息点位置的准确布置. 系统进一步基于数字工程模型和图论基本原理, 实现了从数字工程模型中获取逻辑关系并生成通信逻辑网图. 经实际工程验证, 系统对铁路通信数字工程设计效率和准确率都有较大提升, 从工程源头实现了铁路通信工程数字化成果交付和应用, 促进了铁路通信工程项目全过程技术升级和数字化模式革新.     

Feature modeling for configurable and adaptable modular buildings

Current design approaches for new buildings do not sufficiently plan for or adapt to changing conditions that could be used to extend the useful life of buildings, as part of a circular economy. While notable advances have emerged for using BIM-based configurators to improve building design and project execution, there is a need expand such configurators to look at how buildings can be adapted and re-configured across their lifecycle. This paper develops and demonstrates an innovative feature modeling approach for configuring and adapting modular buildings. This study uses BIM for structuring intricate feature relationships of specific design aspects in terms of product circularity. The design aspects considered are structural design, dimensional variation control, and disassembly planning design. Feature parameter maps, which are a general constraint relation representation, are implemented to describe the data models since they are an efficient way to visualize feature elements and interdependencies, to avoid the creation of redundant information, and to improve data structure consistency. The application of the proposed methodology is validated with a functional demonstration of a conceptual design and optimization for a single module that is meant to be part of a modular construction project. The product model was synthesized in a parametric BIM environment for iterative configuration, analysis of results, and final optimization of the single module assembly. The demonstration case study shows that BIM can be adapted to assist on modeling specific design aspects for modular buildings and to create design alternatives. Also, the method shows a considerable benefit that the designer can produce diverse accurate design alternatives within a reduced amount of time.     

Effective digital collaboration in the construction industry – A case study of BIM deployment in a hospital construction project

Building information modeling (BIM) and related digital innovations can serve as a catalyst for more transparency, tighter integration, and increased productivity in the architecture, engineering, and construction industry. Yet, many project teams struggle with how to work based on the new technology. Collaborative design based on shared information systems like BIM requires changing traditional and institutionalized work practices and routines. A case study of integrated BIM design in a large healthcare construction project serves as an example for how commonly experienced challenges can be overcome. The project has been awarded BuildingSMART's 2015 award for ‘outstanding open BIM practice’ making it Norway's role model for BIM practice. Based on diffusion of innovations theory, we identified the following set of key factors enabling digital collaboration in this project: change agents, new roles and responsibilities, a cloud computing infrastructure, BIM contracts, and a BIM learning environment. The findings presented in this article may serve as an example for BIM implementation and collaborative work in construction projects.     

LiDAR-Derived High Quality Ground Control Information and DEM for Image Orthorectification

Orthophotos (or orthoimages if in digital form) have long been recognised as a supplement or alternative to standard maps. The increasing applications of orthoimages require efforts to ensure the accuracy of produced orthoimages. As digital photogrammetry technology has reached a stage of relative maturity and stability, the availability of high quality ground control points (GCPs) and digital elevation models (DEMs) becomes the central issue for successfully implementing an image orthorectification project. Concerns with the impacts of the quality of GCPs and DEMs on the quality of orthoimages inspire researchers to look for more reliable approaches to acquire high quality GCPs and DEMs for orthorectification. Light Detection and Ranging (LiDAR), an emerging technology, offers capability of capturing high density three dimensional points and generating high accuracy DEMs in a fast and cost-effective way. Nowadays, highly developed computer technologies enable rapid processing of huge volumes of LiDAR data. This leads to a great potential to use LiDAR data to get high quality GCPs and DEMs to improve the accuracy of orthoimages. This paper presents methods for utilizing LiDAR intensity images to collect high accuracy ground coordinates of GCPs and for utilizing LiDAR data to generate a high quality DEM for digital photogrammetry and orthorectification processes. A comparative analysis is also presented to assess the performance of proposed methods. The results demonstrated the feasibility of using LiDAR intensity image-based GCPs and the LiDAR-derived DEM to produce high quality orthoimages.     

BIM技术在水闸设计中的应用

为促进水利建设行业的数字化技术发展,提高设计质量和效率,加快水利工程建设的数字化转型,以崇明岛堡镇港等 4 座水闸外移工程为例,基于 BIM 技术进行参数化设计研究与应用,通过协同设计、参数化模板库、精细化建模、有限元分析等技术实现 BIM 技术在数字设计中的全要素和全过程的应用,推动水闸建设的数字一体化设计的发展,提升设计品质和效率。另外,通过构件数据编码与数字化模型管理平台相连通,实现模型构件、信息的数字化管理及传递,为全生命周期内的智慧工程应用提供坚实的数据基础,有效推进设计过程的精细化管理,为后续其他水利工程项目的 BIM 应用提供良好的理论支持。     

基于粒子群优化算法的无人机航迹规划

提出一种基于粒子群优化算法的无人机航迹规划方法,利用粒子群优化算法,在等效数字地图中实现单个目标点的无人机航迹规划,并对算法性能进行仔细分析,仿真结果表明,该方法能够快速有效地完成航迹规划任务,得到满意的三维航迹。     

Automatic design and planning of scaffolding systems using building information modeling

Considering their significant impact on construction projects, scaffolding as part of the temporary facilities category in construction must be thoroughly designed, planned, procured, and managed. The current practices in planning and managing scaffolding though is often manual and reactive, especially when a construction project is already underway. Widespread results are code compliance problems, inefficiency, and waste of procuring and managing material for scaffolding systems. We developed a rule-based system that automatically plans scaffolding systems for pro-active management in Building Information Modeling (BIM). The scope of the presented work is limited to traditional pipe and board scaffolding systems. A rule was prepared based on the current practice of planning and installing scaffolding systems. Our computational algorithms automatically recognize geometric and non-geometric conditions in building models and produce a scaffolding system design which a practitioner can use in the field. We implemented our automated scaffolding system for a commercially-available BIM software and tested it in a case study project. The system thoroughly identified the locations in need of scaffolding and generated the corresponding scaffolding design in BIM. Further results show, the proposed approach successfully generated a scaffolding system-loaded BIM model that can be utilized in communication, billing of materials, scheduling simulation, and as a benchmark for accurate field installation and performance measurement.     

高分三号卫星在极地冰区导航中的应用评价

针对面向极地冰区船舶航行导航的需求,利用我国第一颗民用合成孔径雷达卫星高分三号(GF-3)数据,通过定量化统计分析,开展了GF-3号标准条带模式数据在极地冰区应用潜力的评估。结果表明,GF-3号标准条带数据能较好地反映冰面的纹理,HH极化在图像层次和信息量上要优于HV极化;在图像的层次表达方面,GF-3/HV极化数据优于Radarsat-2/HV数据,GF-3/HH极化数据不如Radarsat-2/HH极化数据;GF-3数据能较好地反映南极冰区的纹理和类型特征,对于冰山、冰裂隙等冰上障碍具有较好的识别能力,对极地冰区导航和冰上卸货具备较好的应用效果。     

Live semantic data from building digital twins for robot navigation: Overview of data transfer methods

Increasing reliance on automation and robotization presents great opportunities to improve the management of construction sites as well as existing buildings. Crucial in the use of robots in a built environment is their capacity to locate themselves and navigate as autonomously as possible. Robots often rely on planar and 3D laser scanners for that purpose, and building information models (BIM) are seldom used, for a number of reasons, namely their unreliability, unavailability, and mismatch with localization algorithms used in robots. However, while BIM models are becoming increasingly reliable and more commonly available in more standard data formats (JSON, XML, RDF), they become more promising and reliable resources for localization and indoor navigation, in particular in the more static types of existing infrastructure (existing buildings). In this article, we specifically investigate to what extent and how such building data can be used for such robot navigation. Data flows are built from BIM model to local repository and further to the robot, making use of graph data models (RDF) and JSON data formats. The local repository can hereby be considered to be a digital twin of the real-world building. Navigation on the basis of a BIM model is tested in a real world environment (university building) using a standard robot navigation technology stack. We conclude that it is possible to rely on BIM data and we outline different data flows from BIM model to digital twin and to robot. Future work can focus on (1) making building data models more reliable and standard (modelling guidelines and robot world model), (2) improving the ways in which building features in the digital building model can be recognized in 3D point clouds observed by the robots, and (3) investigating possibilities to update the BIM model based on robot feedback.     

Topological integration of BIM and geospatial water utility networks across the building envelope

Utility networks comprise a fundamental part of our complex urban systems and the integration of digital representations of these networks across multiple spatial scales can be used to help address priority challenges. Deteriorating water utility infrastructure and low routing redundancy result in network fragility and thus supply outages when assets fail. Water distribution network configurations can be optimised for higher resilience but digital representations of the networks used for simulations and analyses are not integrated with the finer scale networks inside buildings. This integration is hindered by differences in conceptualisation and semantics employed by the relevant data standards. We suggest that the geospatial and geometric data contained in Building Information Modelling (BIM) and water distribution network (WDN) models can be used for their integration; and that this supports the use cases of optimising dynamic network partitioning, reducing the risk of underground utility strikes and planning for future network configurations with higher topological redundancy. In this study, we develop and demonstrate the application of a weight-based spatial algorithm for inferring water network connections between urban-scale WDNs and BIM models, showing that spatial data can be used in the absence of complete or consistent semantic representations. We suggest that the method has potential for transferability to infrastructure for other utility resources (such as waste water, electricity and gas) and make recommendations such as standardising the representation of connection points between disjoint utility network models and extending the normal practical spatial remit of BIM MEP modelling to encompass the space between buildings and WDNs.