航天器高精度GPS导航定位技术研究

将GPS测量定位技术、求解卫星轨道摄动运动的Encke方法和广义Kalman滤波技术有机地结合在一起，提出了利用GPS实现低轨道航天器高精度自主导航定位的新方法——载波相位-伪距综合动态定轨技术，解决了GPS载波相位应用中动态解模糊和跳周修复的难题。以此为基础，提出了两个航天器之间的载波相位-伪距综合差分动态相对导航技术。数值仿真分析和半物理仿真实验结果表明，所提出的动态定轨技术是可行的，对提高GPS导航定位精度的效果是显著的，并且其模型、算法和软件具有工程实用性。     

GPS伪距差分技术研究

GPS技术随着科技的发展,已经在各个行业发挥着重要作用,同时对定位的精度也提出越来越高得分要求。如何对大量的GPS观测数据进行有效率的处理,以此满足高精度定位就凸显出非常重要的研究意义。主要是从影响局域差分精度的入手,在如何提高定位精度方面进行深入的探讨和研究,分析GPS载波相位平滑伪距差分的工作原理和方法,为GPS提供更为精准、迅速的定位方案。     

未知声速分布下的一种水下目标GPS定位修正算法

由于海洋中声速分布不均匀,要实现水下目标GPS的精确定位,必须进行误差修正。阐述了采用应答器工作模式的水下目标GPS系统定位原理,在水下目标GPS系统定位过程中,分析了一种基于欧氏几何原理的修正算法在声速分布未知时的定位修正效果和局限性,研究了算法出现盲区的原因,并据此对该算法进行了改进。仿真计算结果表明改进后的算法可有效减小声速分布未知时声速估计不准确造成的定位误差,提高了水下目标GPS的定位精度。     

GPS交通调度管理系统的设计与仿真

GPS技术为各种交通工具提供了实时导航定位能力,GPS车辆交通调度管理系统利用全球卫星定位系统、全球移动通信系统、地理信息系统,结合计算机网络通信技术对车辆进行指挥调度和监控.驾驶员和监控中心能够随时通过GSM短消息业务中心传送和查询指定车辆的GPS定位信息.仿真验证了车载导航定位子系统及基站采用的伪距解算软件.     

浅谈伪卫星技术在北斗导航系统中的应用

伪卫星技术是利用伪距测量技术等为基础的一种可以为导航系统提供精确定位的技术,本文在详细介绍北斗导航系统特点的基础上,对伪卫星技术在北斗导航系统中的应用前景作了仔细分析和探讨。     

多目标遥测遥控定位系统的设计与实现

本文介绍多目标遥测遥控定位系统的设计思想、系统构成和工作原理，对系统中的关键技术，发ＧＰＳ差分算法、无线通讯、电子地图制作等，进行了论述。     

基于机器视觉的工业机器人工件搬运技术及应用

机器人通过视觉对工件位置信息进行分析处理,完成相应搬运任务已成为机器人应用发展的方向。该文主要提出了一种基于机器视觉的工业机器人搬运系统,利用相机和机器人进行标定后对工件精确定位,从而实现机器人对工件的识别、定位及搬运工作。     

室内外人员定位报警系统研究及应用

以GPS定位和射频识别技术为基础,以GPRS通信技术为载体设计室内外人员定位报警系统。该系统不仅实现室内和室外精确定位,在紧急情况下还可以进行主动和被动式的报警呼叫。对整个系统的主处理器、射频通信模块、GPS定位模块、GPRS通信模块作详细解析、阐述室内定位的组网方式、定位技术及算法实现,室外GPS定位和GPRS通信的具体模式以及整个系统的低功耗处理。     

基于扩展卡尔曼滤波的轮式移动机器人定位技术

针对单一传感器或现有多传感系统在信息传递提取上的不足,应用一种信息融合方法,对机器人进行相对定位与绝对定位的融合分析,得出机器人的最优位置信息,最终实现了移动机器人的精确定位。首先,采用码盘、陀螺仪进行机器人相对定位,采用激光雷达进行机器人绝对定位;其次,建立环境地图、传感器及机器人运动模型;最后,以扩展卡尔曼滤波作为多传感器融合技术,建立多传感器信息融合模型,实现精确定位。     

GPS发展趋势及其在外弹道测量中的应用展望

本文简要介绍GPS发展概况和现代化发展趋势,对GPS定位模式、特点和精度进行了描述和讨论,用实际算例对单点定位、差分定位、静态相对定位、RTK的精度情况进行验证,并对GPS接收机的发展趋势作了简要描述,最后结合外弹道测量的特点,对GPS在外弹道测量中的应用进行探讨。     

Detection of the Pine Wilt Disease Tree Candidates for Drone Remote Sensing Using Artificial Intelligence Techniques

Pine wilt disease (PWD) has recently caused substantial pine tree losses in Republic of Korea. PWD is considered a severe problem due to the importance of pine trees to Korean people, so this problem must be handled appropriately. Previously, we examined the history of PWD and found that it had already spread to some regions of Republic of Korea; these became our study area. Early detection of PWD is required. We used drone remote sensing techniques to detect trees with similar symptoms to trees infected with PWD. Drone remote sensing was employed because it yields high-quality images and can easily reach the locations of pine trees. To differentiate healthy pine trees from those with PWD, we produced a land cover (LC) map from drone images collected from the villages of Anbi and Wonchang by classifying them using two classifier methods, i.e., artificial neural network (ANN) and support vector machine (SVM). Furthermore, compared the accuracy of two types of Global Positioning System (GPS) data, collected using drone and hand-held devices, for identifying the locations of trees with PWD. We then divided the drone images into six LC classes for each study area and found that the SVM was more accurate than the ANN at classifying trees with PWD. In Anbi, the SVM had an overall accuracy of 94.13%, which is 6.7% higher than the overall accuracy of the ANN, which was 87.43%. We obtained similar results in Wonchang, for which the accuracy of the SVM and ANN was 86.59% and 79.33%, respectively. In terms of the GPS data, we used two type of hand-held GPS device. GPS device 1 is corrected by referring to the benchmarks sited on both locations, while the GPS device 2 is uncorrected device which used the default setting of the GPS only. The data collected from hand-held GPS device 1 was better than those collected using hand-held GPS device 2 in Wonchang. However, in Anbi, we obtained better results from GPS device 2 than from GPS device 1. In Anbi, the error in the data from GPS device 1 was 7.08 m, while that of the GPS device 2 data was 0.14 m. In conclusion, both classifiers can distinguish between healthy trees and those with PWD based on LC data. LC data can also be used for other types of classification. There were some differences between the hand-held and drone GPS datasets from both areas.     

面向大型机场草坪的割草机器人路径规划及轨迹跟踪控制研究

为了提高割草机器人的工作效率及环境适应能力,基于移动机器人平台设计了一种既受遥控操作又能自主运行的适用于大型机场草坪作业的割草机器人。首先,运用高精度差分GPS（global positioning system,全球定位系统）采集机场草坪边界和障碍物的位置信息,根据采集的信息将机场草坪分为最少数目的凸多边形工作区域;考虑到割草机器人无法原地无半径转弯,在传统迂回式路径规划算法的基础上提出一种往返直线型路径规划算法,并在凸多边形路径规划区内推导出遍历路径的显示方程表达式。其次,运用高精度差分GPS测得割草机器人实际轨迹并与规划轨迹对比,设计了一种区间判断型轨迹纠偏算法;以执行电机的PID（proportion integration differentiation,比例积分微分）控制和区间判断型轨迹纠偏算法构造割草机器人双闭环轨迹跟踪控制器,对按传统迂回式路径和往返直线型路径行进的割草机器人进行轨迹跟踪仿真分析。最后,以自制的割草机器人为例,按往返直线型路径运行方式进行样机实验。仿真结果发现：当割草机器人跟踪当前路径到达终点后会自动调头跟踪下一条路径,验证了轨迹跟踪算法的稳定性;传统迂回式路径运行方式下割草机器人的漏割率较高,达到46.42%,而往返直线型路径运行方式下其漏割率为7.15%,明显优于传统迂回式路径仿真结果。样机实验测得的漏割率为8.89%,与仿真实验结果一致,表明所设计的轨迹跟踪算法对大型机场草坪作业割草机器人是适用的。研究结果可为大型机场草坪割草机器人的开发提供理论指导。     

Three-dimensional super-localization and tracking of single gold nanoparticles in cells

We introduce a precise three-dimensional (3D) localization method of spherical gold nanoparticle probes using model-based correlation coefficient mapping. To accomplish this, a stack of sample images at different z-positions are acquired, and a 3D intensity profile of the probe serving as the model is used to map out the positions of nanoparticles in the sample. By using this model-based correlation imaging method, precise localization can be achieved in imaging techniques with complicated point spread functions (PSF) such as differential interference contrast (DIC) microscopy. We demonstrated the localization precision of 4-7 nm laterally and 16 nm axially for 40-nm gold nanospheres at an imaging rate of 10 frames per second. The 3D superlocalization method was applied to tracking gold nanospheres during live endocytosis events.     

基于GPS的蛇形机器人导航方法

将GPS技术应用于蛇形机器人自主运动控制。根据蛇形机器人的基本运动方式,针对其现有的前进、后退、近似角度转弯等运动特点,提出了一种适用于该种蛇形机器人的自主移动算法,即用蛇头运动的方向近似看作蛇体运动方向。通过仿真验证了该算法的有效性,能够使蛇形机器人自主地到达目标点。     

Reconstructing gas distribution maps via an adaptive sparse regularization algorithm

In this paper, we present an algorithm to be used by an inspection robot to produce a gas distribution map and localize gas sources in a large complex environment. The robot, equipped with a remote gas sensor, measures the total absorption of a tuned laser beam and returns integral gas concentrations. A mathematical formulation of such measurement facility is a sequence of Radon transforms, which is a typical ill-posed problem. To tackle the ill-posedness, we develop a new regularization method based on the sparse representation property of gas sources and the adaptive finite-element method. In practice, only a discrete model can be applied, and the quality of the gas distribution map depends on a detailed 3-D world model that allows us to accurately localize the robot and estimate the paths of the laser beam. In this work, using the positivity of measurements and the process of concentration, we estimate the lower and upper bounds of measurements and the exact continuous model (mapping from gas distribution to measurements), and then create a more accurate discrete model of the continuous tomography problem. Based on adaptive sparse regularization, we introduce a new algorithm that gives us not only a solution map but also a mesh map. The solution map more accurately locates gas sources, and the mesh map provides the real gas distribution map. Moreover, the error estimation of the proposed model is discussed. Numerical tests for both the synthetic problem and practical problem are given to show the efficiency and feasibility of the proposed algorithm.     

基于VRML的空间并联机器人运动仿真优化

虚拟现实技术(VRML)经常被运用于机器人仿真,针对传统的并联机器人运动学反解运算量大所引发的仿真系统效率问题,采用VRML的IndexedLineSet节点,通过负载平台的运动学参数动态更新IndexedLineSet节点,并以该节点为基础解出导杆的位姿.通过JavaScript与VRML交互编程实现了6自由度机器人的运动仿真.结果证明,优化后的系统仿真效率相比于传统的方法有很大的提升.     

Carrier-phase time transfer

We have conducted several time-transfer experiments using the phase of the GPS carrier rather than the code, as is done in current GPS-based time-transfer systems. Atomic clocks were connected to geodetic GPS receivers; we then used the GPS carrier-phase observations to estimate relative clock behavior at 6-minute intervals. GPS carrier-phase time transfer is more than an order of magnitude more precise than GPS common view time transfer and agrees, within the experimental uncertainty, with two-way satellite time-transfer measurements for a 2400 km baseline. GPS carrier-phase time transfer has a stability of 100 ps, which translates into a frequency uncertainty of about two parts in 10(-15) for an average time of 1 day.     

基于激光传感器的机器人地图构建方法

针对自主移动机器人局部地图构建问题,分析了几种应用较广的测距传感器的优缺点和地图构建中使用的激光传感器的数学模型及其非线性问题.在给出局部地图构建的一般模型的基础上本文提出了一种机器人局部地图构建的一种新方法,该方法针对传感器数据的不确定问题采用加权最小二乘方法对机器人在导航过程中的局部地图进行构建,具有实现容易、精度较高等特点.仿真和实验结果表明该方法在移动机器人使用激光测距传感器进行环境建模和地图构建过程中可以有效的减小直线拟合误差,进而达到有效建图的目的.     

全向移动机器人驱动万向轮的设计与实现

全向移动机器人使用无解耦机构的驱动万向轮在转向时会派生出额外的滚轮滚动输出,这会导致运动的不稳定以及增加控制算法复杂性.为了解决驱动万向轮转向运动与驱动运动之间的耦合问题,通过在驱动万向轮内加入差速行星齿轮机构,合理地设置该行星齿轮组的输出传动比,可以将转向时的派生滚动输出从转向运动中解耦,实现了对机器人运动的精确控制,提高了机器人运动平稳性.最后通过对机器人进行运动学分析,得到了输入转速与机器人运动速度之间的关系,验证了机器人的全向移动功能,并为机器人运动控制提供了依据.