复杂环境下智能手机RTK+PDR融合定位   总被引：1，自引：0，他引：1  

徐国梁  李圳  陶钧  郭靖  赵齐乐 《测绘通报》2021,(12):44-49,98

针对室外复杂环境下智能手机定位精度低、抗干扰能力不足的问题,本文利用手机GNSS观测值和手机内置IMU数据,采用RTK和PDR算法融合定位,对比分析了小米8和华为Mate20X两款手机的GNSS数据质量和融合定位算法性能,以及不同观测条件下融合算法的定位精度和稳定性。试验结果表明,在良好和复杂两种观测条件下,采用RTK算法定位精度分别为1.8 m和4.6 m;采用RTK+PDR融合算法定位精度分别为1.2 m和2.6 m,在两种环境下,RTK+PDR融合算法的精度分别提高了50%和76%,即显著提高了智能手机在室外复杂环境下的定位精度。  相似文献   

基于车载激光点云的高精地图矢量化成图     

赵焰  曹聿铭  黄鹤 《测绘通报》2021,(12):105-109,114

针对车载激光点云中对各特征物提取结果后矢量化成图时的自动化问题,本文基于双方向积分法实现了边缘检测及矢量化成图,旨在保证特征物基本特征的同时,也保证点云的绝对精度。将输入的特征点云进行离群点过滤,以保证外包框算法特征点云的准确度;将三维点云按照外包框算法投影至最优平面,为后续沿各方向积分提供输入;利用八邻域KD-tree算法求出样本特征点云的均值邻域半径,依据邻域半径对各方向积分提供积分域中的微分元;根据提供的微分元沿各方向进行积分,在该积分元内找到距平面最值的最优解;按照积分结果构建点云索引,并根据点云特征构建模型,最终得到高精地图的矢量化点云。试验证明了该方法在处理实际问题时的可行性。  相似文献   

复杂城区车载激光扫描点云分层路段定位与数据纠正实验研究     

王胜利  郝国建  蒋毅  孙磊  杨红军 《测绘工程》2021,30(2):26-31

高精度的车载点云数据是实现各种城市地物要素提取的前提,但在复杂城市环境下车载作业时信号遮挡、衰减和多径效应频繁发生,进而造成点云数据精度严重降低,如何对复杂环境下的点云数据进行分析和纠正就显得至关重要。现有的质量分析方法多从测距误差、仪器安装误差和数据处理误差方面出发,虽然可以在一定程度上改化数据,但在如何快速定位出分层路段以及复杂城区道路纠正方面缺乏深入研究。城区交通状况复杂、高楼林立以及树木密集等不利条件影响数据精度,因此文中研究三维点云数据分层路段快速定位方法以及分层点云纠正技术,以提升点云数据精度与质量。试验结果表明该方法能够快速定位到质量不佳的路段,研究成果可为复杂城区环境下点云数据质量提升提供一定借鉴。  相似文献   

系统偏差常数弧段估计策略对多系统静态精密单点定位的影响     

洪菊  涂锐  王星星  刘崇锦  刘金海  黄小东  卢晓春 《大地测量与地球动力学》2019,39(9):947-951

为探讨系统偏差最优估计策略，利用IGS提供的GPS、BDS、GLONASS和Galileo 四系统的观测数据以及GFZ提供的精密卫星钟差和精密轨道产品，将系统偏差（ISB）按照高斯白噪声、20 min、30 min、1 h、2 h分段常数进行单天静态解，分别获得E、N、U方向上的坐标偏差，分析不同系统偏差求解策略下多系统融合PPP的收敛时间和定位精度。结果表明，在多系统融合静态PPP中，从观测模型强度与定位结果稳定性和可靠性角度综合考虑，对ISB采用20 min分段常数估计策略是最优的，静态PPP收敛时间在30 min左右，收敛后的定位精度E方向优于2 cm、N方向优于1 cm、U方向优于5 cm。  相似文献   

An adaptive finite element model for wellbore breakout simulation     

Diogo L. Cecílio  Philippe R. B. Devloo  Sônia M. Gomes  Erick S.R. Santos 《国际地质力学数值与分析法杂志》2019,43(4):814-828

A finite element formulation is proposed and implemented for analysing the stability of excavated wells using the DiMaggio-Sandler constitutive elastoplastic model with a typical carbonate reservoir configuration. The quality of the finite element approximation is ensured by applying smooth curved elements adapted to the wellbore geometry, and h − p adaptive finite element meshes in the plastic zone. General purpose procedures are defined to transfer the elastoplastic deformation history to newly created integration points. A breakout damage criterion is proposed based on the second invariant of the deviatoric plastic deformation tensor. This damage criterion is used to apply a mesh movement algorithm to represent material collapse. The automatic successive application of the breakout damage criterion results in elliptical realistically looking geometries obtained in experiments reported in the literature.  相似文献   

改进A?的高层建筑逃生路径规划算法研究   总被引：1，自引：0，他引：1  

靳海亮  王赢乐  袁鸣  陈梦龙 《测绘通报》2019,(11):17-21,25

针对高层建筑内部结构复杂，发生火灾时没有疏散引导情况，逃生通道极易发生拥堵导致疏散效率降低的问题，本文基于对A*算法的改进，提出了高层建筑逃生路径规划算法。该算法以高层建筑内部路网节点为关键要素，综合火灾发生位置、人员密度、人员数量等因素，从逃生终点优化分配、节点扩展优化、权值优化3个方面进行改进，实现了火灾发生时高层建筑内部的逃生路径规划，并以某高层建筑为例，验证了本文算法的可行性。  相似文献   

Estimation of crowd density from UAVs images based on corner detection procedures and clustering analysis     

Ali Almagbile 《地球空间信息科学学报》2019,22(1):23-34

With rapid developments in platforms and sensors technology in terms of digital cameras and video recordings, crowd monitoring has taken a considerable attentions in many disciplines such as psychology, sociology, engineering, and computer vision. This is due to the fact that, monitoring of the crowd is necessary to enhance safety and controllable movements to minimize the risk particularly in highly crowded incidents (e.g. sports). One of the platforms that have been extensively employed in crowd monitoring is unmanned aerial vehicles (UAVs), because UAVs have the capability to acquiring fast, low costs, high-resolution and real-time images over crowd areas. In addition, geo-referenced images can also be provided through integration of on-board positioning sensors (e.g. GPS/IMU) with vision sensors (digital cameras and laser scanner). In this paper, a new testing procedure based on feature from accelerated segment test (FAST) algorithms is introduced to detect the crowd features from UAV images taken from different camera orientations and positions. The proposed test started with converting a circle of 16 pixels surrounding the center pixel into a vector and sorting it in ascending/descending order. A single pixel which takes the ranking number 9 (for FAST-9) or 12 (for FAST-12) was then compared with the center pixel. Accuracy assessment in terms of completeness and correctness was used to assess the performance of the new testing procedure before and after filtering the crowd features. The results show that the proposed algorithms are able to extract crowd features from different UAV images. Overall, the values of Completeness range from 55 to 70 % whereas the range of correctness values was 91 to 94 %.  相似文献   

Indoor localization for pedestrians with real-time capability using multi-sensor smartphones     

Catia Real Ehrlich 《地球空间信息科学学报》2019,22(2):73-88

ABSTRACT

The localization of persons or objects usually refers to a position determined in a spatial reference system. Outdoors, this is usually accomplished with Global Navigation Satellite Systems (GNSS). However, the automatic positioning of people in GNSS-free environments, especially inside of buildings (indoors) poses a huge challenge. Indoors, satellite signals are attenuated, shielded or reflected by building components (e.g. walls or ceilings). For selected applications, the automatic indoor positioning is possible based on different technologies (e.g. WiFi, RFID, or UWB). However, a standard solution is still not available. Many indoor positioning systems are only suitable for specific applications or are deployed under certain conditions, e.g. additional infrastructures or sensor technologies. Smartphones, as popular cost-effective multi-sensor systems, is a promising indoor localization platform for the mass-market and is increasingly coming into focus. Today’s devices are equipped with a variety of sensors that can be used for indoor positioning. In this contribution, an approach to smartphone-based pedestrian indoor localization is presented. The novelty of this approach refers to a holistic, real-time pedestrian localization inside of buildings based on multi-sensor smartphones and easy-to-install local positioning systems. For this purpose, the barometric altitude is estimated in order to derive the floor on which the user is located. The 2D position is determined subsequently using the principle of pedestrian dead reckoning based on user's movements extracted from the smartphone sensors. In order to minimize the strong error accumulation in the localization caused by various sensor errors, additional information is integrated into the position estimation. The building model is used to identify permissible (e.g. rooms, passageways) and impermissible (e.g. walls) building areas for the pedestrian. Several technologies contributing to higher precision and robustness are also included. For the fusion of different linear and non-linear data, an advanced algorithm based on the Sequential Monte Carlo method is presented.  相似文献   

Water level observations from unmanned aerial vehicles for improving estimates of surface water–groundwater interaction          下载免费PDF全文

Filippo Bandini  Michael Butts  Torsten Vammen Jacobsen  Peter Bauer‐Gottwein 《水文研究》2017,31(24):4371-4383

Integrated hydrological models are usually calibrated against observations of river discharge and piezometric head in groundwater aquifers. Calibration of such models against spatially distributed observations of river water level can potentially improve their reliability and predictive skill. However, traditional river gauging stations are normally spaced too far apart to capture spatial patterns in the water surface, whereas spaceborne observations have limited spatial and temporal resolution. Unmanned aerial vehicles can retrieve river water level measurements, providing (a) high spatial resolution; (b) spatially continuous profiles along or across the water body, and (c) flexible timing of sampling. A semisynthetic study was conducted to analyse the value of the new unmanned aerial vehicle‐borne datatype for improving hydrological models, in particular estimates of groundwater–surface water (GW–SW) interaction. Mølleåen River (Denmark) and its catchment were simulated using an integrated hydrological model (MIKE 11–MIKE SHE). Calibration against distributed surface water levels using the Differential Evolution Adaptive Metropolis algorithm demonstrated a significant improvement in estimating spatial patterns and time series of GW–SW interaction. After water level calibration, the sharpness of the estimates of GW–SW time series improves by ~50% and root mean square error decreases by ~75% compared with those of a model calibrated against discharge only.  相似文献   

Retaining wall optimization using interior search algorithm with different bound constraint handling          下载免费PDF全文

A.H. Gandomi  A.R. Kashani  F. Zeighami 《国际地质力学数值与分析法杂志》2017,41(11):1304-1331

Along with the applicability of optimization algorithms, there are lots of features that can affect the functioning of the optimization techniques. The main purpose of this paper is investigating the significance of boundary constraint handling (BCH) schemes on the performance of optimization algorithms. To this end, numbers of deterministic and probabilistic BCH approaches are applied to one of the most recent proposed optimization techniques, named interior search algorithm (ISA). Apart from the implementing different BCH methods, a sensitivity analysis is conducted to find an appropriate setting for the only parameter of ISA. Concrete cantilever retaining wall design as one of the most important geotechnical problems is tackled to declare proficiency of the ISA algorithm, on the one hand, and benchmark the effect of BCH schemes on the final results, on the contrary. As results demonstrate, various BCH approaches have a perceptible impact on the algorithm performance. In like manner, the essential parameter of ISA can also play a pivotal role in this algorithm's efficiency. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献