一种车辆GPS轨迹数据的改进地图匹配算法

文中提出一种车辆GPS轨迹数据的改进地图匹配算法.以车辆GPS轨迹数据进行隐马尔可夫模型动态地图匹配后的缓冲区内候选路径为初始群体,以遗传算法中的改进的适应度函数为基准进行半交叉迭代,选择车辆轨迹更优的匹配路径;设计了改进地图匹配方法的算法流程;利用微软亚洲团队的GeoLift轨迹数据集验证了改进方法的有效性.

基于GPS数据的实验室制氢废液污染实时监测

为了提高制氢废液污染监测效果,文中提出基于GPS数据的实验室制氢废液污染实时监测方法。利用GPS系统采集污染数据,通过串口读取GPS数据,定位污染位置。以降低监测能耗为目的,采用在线监测机制和短信通知监测相互转换形式实现实验室制氢废液污染实时监测。结合GPS、GPRS、GIS三种技术对监测所得数据进行管理与分析,为实验室制氢废液污染治理提供技术支持。通过实际应用结果表明,文中设计方法监测能耗较低,安全性强,监测数据传输效率较高,证明所提方法具有较好的应用性能,可用于实验室制氢废液污染的实时监测。

基于GPS数据的高速公路行程时间估计与可靠性分析

准确地进行高速公路行程时间估计与可靠性分析对交通规划与缓解交通拥堵具有重要意义。针对目前行程时间估计准确性不高、可靠性分析不够全面的问题,提出基于BP神经网络的高速公路行程时间估计模型,并利用该模型计算的行程时间分析高速公路上车辆行驶的行程时间可靠性。以广州机场高速公路GPS浮动车数据为例进行实例验证,结果表明,与速度-时间积分法和位置-时间内插法相比,本文提出的模型提高了行程时间估计的准确度,同时能多方面地分析车辆行程时间的可靠性。

基于卡尔曼滤波的北斗/GPS双模数据融合轨迹定位

全球卫星导航系统中,高精度定位是关键的性能指标之一。目前,我国自主研发的北斗卫星导航系统(以下简称:BDS)与美国主导的全球卫星定位系统(GPS)处于世界领先地位。虽然其定位精度较高,但硬件级系统的固有问题,使定位仍然存在误差。该项目基于卡尔曼滤波法,通过双模定位模块,将BDS与GPS的定位数据进行融合,极大地提高了定位精度,降低了误差。

基于GPS与手机信令数据的上海货运枢纽交通特征研究

针对传统道路货运调查抽样率较低、调查成本较高、时效性较差,难以反映货运枢纽集散过程连续性和关联性特征的问题,基于货运交通流自有的时间序列特性,提出12t及以上货车GPS与道路匹配的方法和运用手机信数据令识别货车司机的方法,并给出数据模型结构和算法关键步骤。结论表明,用2种数据分析方法得到货运枢纽交通来源去向分布、集散路径及车速特征,与上海市交通运行年报反映的道路货运发展现状相符,通过手机信令数据识别出的货车司机人数与实际数量相当,所提出的货车集散路径算法具有准确性和实用性,为摸清货运枢纽道路交通空间利用状况,提高货运系统规划及运营管理水平提供技术支撑。

安全壳喷淋泵试验卸载时间超差原因分析及GPS校时模块应用优化

压水堆核电机组的计算机系统担负着对各个系统数据采集并送到主控室显示、对现场设备进行监测的重要任务。其中高精度时间显示作为核安全相关设备定期试验的重要参考依据,往往成为试验是否合格的关键。例如在执行应急柴油发电机组低负荷运行性能试验期间,多次出现了安全壳喷淋系统泵试验卸载时间超差的情况,导致该试验结果不合格。本文通过对秦山第二核电厂3、4号机组核电厂计算机系统数据采集监督的问题进行分析与探讨,找出了安全壳喷淋系统泵试验卸载时间不合格的根本原因,并制定了解决方案,最终通过分析与验证,该方案是合理可行的。

基于甘肃省货运 GPS 数据的货运走行时空规律探索

大数据时代背景下,对车辆的GPS(global positioning system,全球定位系统)轨迹数据进行研究分析,能够帮助交通管理者充分了解交通态势及发展趋势,为精细化管理提供数据支撑。为通过货运车辆运行情况探索甘肃省货运规律,以甘肃省货运车辆GPS数据为例,充分关联区域内的相关产业分布,分析货运走行规律,探索区域货运态势,通过等时差抽取估算法得到产业分布情况、货运OD(Origin and destination,起讫点)情况、货运通道偏好情况、货运车辆停留点分布情况等4项交通分析结果。采取等时差抽取估算法省去了对所有车辆逐一进行轨迹重构的工作量,可直接估算出道路的单公里货运车辆流量值,并且最终结果显示误差率在5%以内,可为同类研究提供借鉴。

结合GPS的船舶试航系统数据通信技术

我国是船舶制造大国,船舶试航是船舶制造过程中的关键步骤之一。传统的船舶试航耗费时间较长,且需要对大量数据进行归纳、整理和分析。本文结合GPS技术和4G技术,提出一种船舶试航数据通信系统,对GPS技术、4G技术进行阐述,设计船舶试航数据通信系统的基本架构,介绍系统中不同模块的功能,设计系统软件,搭建系统测试环境,对系统通信效果进行测试。测试结果表明,系统具有较高的稳定性,时延较小,数据传输速率较高,满足系统设计要求。

基于GPS数据的公交站运行状态分析

为有效提高公交站点的运行效率,对公交站的运行状态进行识别、预测及影响因素分析,以中国西安市公交车全球定位系统轨迹数据为例,建立平均服务时间和服务车数特征参数反映公交站的运行状态,并通过分析站点内公交车辆速度、里程及加速度之间关系计算站台服务时间.使用Hopkins统计量和轮廓系数分析可聚性和聚类数,结合高斯混合模型(Gaussian mixture model,GMM)对公交站运行状态进行识别分类.构建SMOTEENN-XGBoost(synthetic minority oversampling technique edited nearest neighbours-extreme gradient boosting)站点运行状态预测模型,引入可解释机器学习框架SHAP(Shapley additive explanation)分析站台属性、道路及环境对模型的影响.结果表明,公交站运行状态可分为3类,类型Ⅰ的平均服务时间最长,类型Ⅱ的平均服务时间和服务车数最少,类型Ⅲ的服务车数最多;所建立SMOTEENN-XGBoost模型的准确率为94.68%,精确率为94.69%,召回率为91.04%,F1分数为92.26%,与极限梯度提升(extreme gradient boosting,XGBoost)、逻辑回归(logistic regression,LR)、随机森林(random forest,RF)、梯度提升决策树(gradient boosting decision tree,GBDT)和k近邻(k-nearest neighbors,KNN)5种模型对比,本模型能够精准预测站点运行状态;对站点运行状态具有影响作用的因素按照重要程度由大到小依次为线路数、有无公交专用道、泊位数、站台设置方法、站台几何形状、车道数、站台设置位置、是否工作日、时段及天气类型.研究结果可为公交站点设计优化提供一定参考依据.

基于手机GPS数据的个体出行链提取方法研究

针对现状出行数据存在的人工获取成本高、时空信息不准确及出行链接不完整等问题,开发智能手机居民出行调查系统,研究基于手机GPS数据的全时段、多交通方式且完整链接的个体出行链提取方法。首先,应用时空密度聚类方法,识别个体轨迹中的停驻点,构建随机森林模型,从停驻点中区分出行端点;其次,以空间邻近匹配方法识别居家与工作活动,利用家庭和个人属性、活动时空与活动链等特征,以XGBoost模型推断非家非工作类型的出行目的;最后,采用轨迹微分方法,提取运动特征、出行特征与GIS特征,运用XGBoost模型推断出行方式。利用出行调查系统采集的实验数据,验证出行链提取方法。结果表明:停驻点识别查准率和查全率分别为96.7%和96.4%,出行端点查准率为97.6%,公交换乘点查准率为91.8%;出行目的推断上,“居家/回家”准确率为100%,“上班/上学”准确率为89.8%,非家非工作出行目的综合准确率为87.6%;出行方式推断上,各交通方式准确率均达到90%以上,综合准确率为95.0%。本文提供一种手机GPS轨迹数据的出行链挖掘方法,能够为智能手机居民出行调查现实应用提供支撑。

智能手机BDS-3/GPS数据质量及SPP性能分析

使用可观测到BDS-3 B1I/B1C/B2a频率和GPS L1/L5频率的智能手机Xiaomi 11(青春版)作为研究对象,分别进行静态实验和不同场地的动态实验,分析手机输出的三频BDS和双频GPS原始观测数据质量及单频SPP性能。实验结果表明,智能手机的GNSS天线成本低致使其信号质量不佳,其中GPS L1频率和BDS B1C频率抗干扰性较强:BDS B1C频率定位结果在静态和动态实验中均较为稳定;GPS L1频率定位结果在动态实验中优于GPS L5频率,在静态实验中略差于GPS L5频率。

Contemporary crustal tectonic movement in the southern Sichuan-Yunnan block based on dense GPS observation data

We analyzed 360 permanent and campaign GPS data from 1999 to 2017 in the southern Sichuan-Yunan block, and obtained crustal horizontal deformation in this region.Then, we derived the strain rate using a multi-scale spherical wavelet method.Results reveal a complex pattern of tectonic movement in the southern Sichuan-Yunnan block.Compared to the stable Eurasian plate, the maximum rate of the horizontal deformation in the southern Sichuan-Yunnan block is approximately 22 mm/a.The Xiaojiang fault shows a significantly lower deformation—a left-lateral strike-slip movement of 9.5 mm/a.The Honghe fault clearly shows a complex segmental deformation from the north to south.The northern Honghe fault shows 4.3 mm/a right strike-slip with 6.7 mm/a extension; the southern Honghe fault shows 1.9 mm/a right strike-slip with 1.9 mm/a extension; the junction zone in the Honghe and Lijiang–Xiaojinhe faults shows an obvious clockwise-rotation deformation.The strain calculation results reveal that the maximum shear-strain rate in this region reaches 70 nstrain/a, concentrated around the Xiaojiang fault and at the junction of the Honghe and Lijiang–Xiaojinhe faults.We note that most of the earthquakes with magnitudes of 4 and above that occurred in this region were within the high shear strain-rate zones and the strain rate gradient boundary zone, which indicates that the magnitude of strain accumulation is closely related to the seismic activities.Comparison of the fast shear-wave polarization direction of the upper-crust with the upper-mantle anisotropy and the direction of the surface principal compressive strain rate obtained from the inversion of the GPS data reveals that the direction of the surface principal compressive strain is basically consistent with the fast shear-wave polarization direction of the upper crust anisotropy, but different from the polarization direction of the upper mantle.Our results support the hypothesis that the principal elements of the deformation mechanism in the southern Sichuan-Yunnan block are decoupling between the upper and lower crust and ductile flow in the lower crust.

基于GPS数据的桂林龙脊梯田遗产地游客时空行为特征及其影响因素

明晰游客时空行为特征对遗产资源的有效保护与合理利用具有重要意义。以桂林龙脊梯田遗产地为例,基于两步路户外平台,爬取游客活动的GPS轨迹数据和位置照片数据,利用GIS空间分析、空间句法等深度剖析游客时空行为特征。结果表明:1)在时间上,龙脊梯田旅游年内分异特征明显,春季至秋季是旅游的旺季,在10月游客更宜出游,日内不同时间区间游客活动有明显的空间集聚和方向性;2)在空间上,游客兴趣点呈“两核多点”式的分布特征,形成了以山地环境为依托、民族村寨为载体、观景台为导向、路网为骨架串联的点线面立体网络游赏体系;3)游客行为特征在时空上分布不均衡,主要受气候变化与景观资源特性、产品体系丰富度、地形及景观偏好影响较大。基于以上分析,提出龙脊梯田遗产地旅游开发与文化传承的引导策略。

GPS-RTK定位技术在某公路工程中的应用研究

针对传统测绘技术存在耗时长、误差大等缺点,提出将GPS-RTK技术应用于某公路工程测量,利用GPS-RTK技术进行工程的四等GPS控制网测量、四等水准测量和地形图测量,并进行实测数据质量分析。结果表明:GPS-RTK技术测量所得数据精度均小于规范限制,将GPS-RTK技术应用于公路工程能够显著提高测量精度和工作效率;GPS-RTK技术应用于地形图测量的平面互差小于50 mm,高程互差小于100 mm;GPS-RTK技术测得的边长检测误差小于15 mm,高层检测误差小于40 mm。

基于GPS数据的危险品运输车辆行程链聚类研究

为帮助政府相关部门精细化监管危险化学品运输,提出一种基于全球定位系统(GPS)数据的危险品运输车辆行程链聚类分析框架。设置时空阈值,从GPS数据中提取车辆基站和中途有效停车点,生成危险品运输车辆行程链;在计算行程链数、平均停车点数、平均行程链停车时长和平均行程链距离等已有指标的基础上,使用平均行程风险和平均停车点风险衡量危险品运输车辆行程风险;以行程链特征为聚类指标,轮廓系数与误差平方和为评估指标,比选K-Means、K-Means++、PAM、FCM这4种算法的行程链聚类效果;通过实际案例分析验证框架的可行性。结果表明:K-Means++算法效果最佳,危险品运输车辆被分为化工园区接驳(44.19%)、城际运输(31.42%)、城市配送(13.23%)、场站接驳(9.76%)和非工作状态(1.40%)5类。

A PRELIMINARY STUDY ON THE QUALITY CONTROL METHOD FOR GUANGDONG GPS/PWV DATA AND ITS EFFECTS ON PRECIPITATION FORECASTS IN ITS ANNUALLY FIRST RAINING SEASON

We first analyzed GPS precipitable water vapor(GPS/PWV) available from a ground-based GPS observation network in Guangdong from 1 August 2009 to 27 August 2012 and then developed a method of quality control before GPS/PWV data is assimilated into the GRAPES 3DVAR system. This method can reject the outliers effectively. After establishing the criterion for quality control, we did three numerical experiments to investigate the impact on the precipitation forecast with and without the quality-controlled GPS/PWV data before they are assimilated into the system.In the numerical experiments, two precipitation cases(on 6 to 7 May, 2010 and 27 to 28 April, 2012 respectively) that occurred in the annually first raining season of Guangdong were selected. The results indicated that after quality control,only the GPS/PWV data that deviates little from the NCEP/PWV data can be assimilated into the system, has reasonable adjustment of the initial water vapor above Guangdong, and eventually improves the intensity and location of 24-h precipitation forecast significantly.

The Quality Assessment of Non-Integer-Hour Data in GPS Broadcast Ephemerides and Its Impact on the Accuracy of Real- Time Kinematic Positioning Over the South China Sea

Abnormal effects in GPS broadcast ephemerides can have a significant effect on real-time navigation and positioning solutions that use the orbit and clock error data provided by GPS broadcast ephemerides.This paper describes three types of non-integerhour navigation data in GPS broadcast ephemeris data.Compared with GPST integer hour data,we find that there are two types of data blocks for non-integer-hour navigation containing gross errors with different levels of precision,which is reflected in the user range accuracy(URA)of the broadcast ephemeris.These gross errors can cause large deviations when using the GPS broadcast ephemeris for orbit calculation and lead to a decrease in the kinematic positioning accuracy.An improved weighting method which is based on the consistency relationship between the URA value and the orbital precision is proposed to improve the positioning accuracy by controlling the effect of gross errors in the broadcast ephemerides.The correction algorithm proposed in this paper was applied to real-time kinematic positioning with shipborne GPS data over the South China Sea.The results showed that the proposed positioning algorithm can effectively reduce the effects of gross errors in the broadcast ephemeris,and significantly improve the accuracy of the navigation and positioning.

Parallel Computing of a Variational Data Assimilation Model for GPS/MET Observation Using the Ray-Tracing Method

The Spectral Statistical Interpolation (SSI) analysis system of NCEP is used to assimilate meteorological data from the Global Positioning Satellite System (GPS/MET) refraction angles with the variational technique. Verified by radiosonde, including GPS/MET observations into the analysis makes an overall improvement to the analysis variables of temperature, winds, and water vapor. However, the variational model with the ray-tracing method is quite expensive for numerical weather prediction and climate research. For example, about 4 000 GPS/MET refraction angles need to be assimilated to produce an ideal global analysis. Just one iteration of minimization will take more than 24 hours CPU time on the NCEP's Gray C90 computer. Although efforts have been taken to reduce the computational cost, it is still prohibitive for operational data assimilation. In this paper, a parallel version of the three-dimensional variational data assimilation model of GPS/MET occultation measurement suitable for massive parallel processors architectures is developed. The divide-and-conquer strategy is used to achieve parallelism and is implemented by message passing. The authors present the principles for the code's design and examine the performance on the state-of-the-art parallel computers in China. The results show that this parallel model scales favorably as the number of processors is increased. With the Memory-IO technique implemented by the author, the wall clock time per iteration used for assimilating 1420 refraction angles is reduced from 45 s to 12 s using 1420 processors. This suggests that the new parallelized code has the potential to be useful in numerical weather prediction (NWP) and climate studies.

Rupture process of the 2011 Tohoku earthquake from the joint inversion of teleseismic and GPS data

Teleseismic and GPS data were jointly inverted for the rupture process of the 2011 Tohoku earthquake. The inversion results show that it is a bilateral rupture event with an average rupture velocity less than 2.0 km/s along the fault strike direction. The source rupture process consists of three sub-events, the first occurred near the hypocenter and the rest two ruptured along the updip direction and broke the sea bed, causing a maximum slip of about 30 m. The large-scale sea bed breakage may account for the tremendous tsunami disaster which resulted in most of the death and missing in this mega earthquake.

Data Transformation for Super-totalstation Positioning System Integrated by GPS and Totalstation

This paper focuses on the integration and data transformation between GPS and totalstation.It emphasizes on the way to transfer the WGS84 Cartesian coordinates to the local two_dimensional plane coordinates and the orthometric height GPS receiver,totalstation,radio,notebook computer and the corresponding software work together to form a new surveying system,the super_totalstation positioning system(SPS) and a new surveying model for terrestrial surveying.With the help of this system,the positions of detail points can be measured.