Effects of Uncertainties in the Position and Orientation of Both the Transmitter and Receivers on Marine Controlled-Source Electromagnetic Data

Simulation and interpretation of marine controlled-source electromagnetic(CSEM) data often approximate the transmitter source as an ideal horizontal electric dipole(HED) and assume that the receivers are located on a flat seabed.Actually,however,the transmitter dipole source will be rotated,tilted and deviated from the survey profile due to ocean currents.And free-fall receivers may be also rotated to some arbitrary horizontal orientation and located on sloping seafloor.In this paper,we investigate the effects of uncertainties in the transmitter tilt,transmitter rotation and transmitter deviation from the survey profile as well as in the receiver's location and orientation on marine CSEM data.The model study shows that the uncertainties of all position and orientation parameters of both the transmitter and receivers can propagate into observed data uncertainties,but to a different extent.In interpreting marine data,field data uncertainties caused by the position and orientation uncertainties of both the transmitter and receivers need to be taken into account.

A Position and Orientation Compensation Mechanism for Automatic Docking Device of Launch Rocket

A position and orientation compensation mechanism for the automatic docking device of a launch rocketwas established.The docking process was simulated,and the maximum docking deviation was used for the prototype testing of the compensation mechanism.The compensation mechanism mainly comprises four column pairmotion branch chains with the same structure.When the position of the ground connector panel changes relative to the moving platform,the sliding rods in the four motion branch chains move and rotate to either compress or stretch the connected spring,thereby compensating the position and orientation.First,the dynamic simulation model of the compensation mechanism was established.The docking process was then simulated under the maximum docking deviation.Bench testing of the automatic docking device prototype was carried out.Afterwards,the device was manufactured,and a maximum load test and maximum deviation test were carried out.The results demonstrate that the compensation mechanism meets the design requirements,and the spring stiffness was found as the most important factor in determining the mechanical properties of the system.The proposed compensation mechanism has a number of advantages,including a simple structure,large load bearing capacity,small size,simple installation,and adjustment.

METHODS OF VISUAL RECOGNITION,POSITIONING AND ORIENTATING OF 3 D SIMPLE GEOMETRIC WORKPIECE

The methods of visual recognition,positioning and orienting with simple 3 D geometric workpieces are presented in this paper.The principle and operating process of multiple orientation run length coding based on general orientation run length coding and visual recognition method are described elaborately.The method of positioning and orientating based on the moment of inertia of the workpiece binary image is stated also.It has been applied in a research on flexible automatic coordinate measuring system formed by integrating computer aided design,computer vision and computer aided inspection planning,with a coordinate measuring machine.The results show that integrating computer vision with measurement system is a feasible and effective approach to improve their flexibility and automation.

Robot Positioning Based on Multiple Quick Response Code Landmarks

The scheme of robot positioning based on multiple quick response(QR)code landmarks is proposed.Firstly,the pose of the robot relative to the QR code landmarks is obtained by extracting the feature points of the QR code,combined with the visual computing technology.Then,the conversion of the absolute pose of the robot is completed based on the absolute position of the QR code landmark,and thus the real-time position of the robot is obtained.The proposed scheme makes full use of the QR code fault tolerance and multiple QR code landmarks to improve the calculation accuracy.It has good robustness and versatility,and it is easy to implement.It can help the robot to complete the positioning in the actual work,making robot navigation more accurate.

紧组合惯导系统精度分析——以Applanix POS MV为例

随着移动测量技术发展,对高精度、连续、可靠、稳定的导航定位数据需求日益增多。本文针对复杂动态环境下单独GNSS导航定位难题,利用Applanix POS MV开展紧组合惯导系统精度试验研究。结论为:①紧组合导航定位精度明显优于单独GNSS PPK定位模型,尤其在角速率、姿态变化较大区域,组合导航定位精度优势更为显著;②紧组合导航定位系统跟踪所有卫星精度最高,关闭北斗卫星与仅跟踪GPS卫星精度相当,关闭GPS卫星精度损失严重;③紧组合导航定位系统PPK辅助定位精度优于RTX辅助定位精度,但RTX精度均优于0.05 cm,可满足大比例尺测图精度要求。结果表明,利用PPK或RTX辅助紧组合惯导系统在复杂情况下仍可提供高精度、连续、可靠、稳定导航定位数据。

国产MPOS系统精度测试与评估方法

微小型位置姿态测量系统(MPOS)是为观测载荷提供实时运动补偿信息的关键设备。针对国产MPOS在实时单点、事后差分和实时差分(RTK)定位等不同工作模式下的精度测试问题,结合通用航空载荷研制要求和摄影测量工程应用经验,提出了一种基于基准POS直接对比的测试方法和基于POS辅助空中三角测量方法,对国产MPOS测量精度及成图精度开展综合分析评估。结果表明,提出的直接对比法及航测成图法能够真实、客观反映国产MPOS系统在实际工程应用中的性能状态,且在相对理想作业条件下,采用一定数量控制点参与区域网联合平差,能够满足1∶1000成图限差要求,测量精度及工程应用效能与APX-15 UAV等国外同类型产品水平相当。

Three Academic Problems on Music Iconography in China： Direction, Position, and Path

As an emerging discipline which interrelates with musicology and iconology, the Music Iconography in China is still at the beginning stage. In the past 30 years, its research methods have been the focus of debate in regard to its academic direction, academic position, and academic path. These three ＂academic problems＂ should be paid attention because they not only sustain our current research and construction of Music Iconography＇s future and destiny, but also become major theoretical and practical issues. The author advocates that the academic direction should maintain highly consistent with the reality of China, as well as the academic practice. In order to guarantee the academic direction and academic position, we should adopt the academic path from these two aspects： ＂the horizontal logic＂ and ＂the longitudinal logic＂

Characterization of (100)-orientated diamond film grown by HFCVD method with a positive DC bias voltage

The (100)-orientated diamond film was deposited by hot-filament chemical vapor deposition (HFCVD) technology with a positive DC bias voltage. The morphology, X-ray diffraction (XRD), RAMAN spectrum and dark current versus applied voltage characteristics analysis show that the positive dc bias can increase the nucleation density and (100)-orientated growth, making the growth of the high quality diamond film easier and cheaper than using other methods.

MPOS联邦实时组合算法

微小型位置姿态测量系统(micro position and orientation system,MPOS)是为成像载荷提供实时高精度运动补偿信息的关键装置,其测量精度严重制约成像精度的提升。针对MPOS集中滤波实时性差的问题,在基于双ARM(advanced reduced instruction set computing machines)硬件平台的基础上,采用联邦滤波实时组合算法对多组传感器数据进行最优信息融合。以微惯性测量单元为公共参考系统,双天线全球导航卫星系统(global navigation satellite system,GNSS)和磁强计作为子系统提供量测信息,将各个子系统得到的局部误差协方差及状态估计值在主滤波器中进行信息融合得到最优估计值。通过动态实验验证了基于联邦滤波实时组合方法的MPOS,其位置、速度、航向角及水平姿态角精度可达0.6 m,0.03 m/s,0.15°,0.04°。

顾及地面POS信息的空地一体城市三维实景重建

实景三维模型为数字孪生提供了统一的数字空间底座。在城市场景中,贴近地面及在空中视角下被遮挡的地物是实景三维重建的难点。针对城市复杂空间环境和无人机飞行局限的问题,本文基于倾斜摄影与空地一体融合建模的基础理论,考虑POS信息对空地一体空三融合的影响,提出了一种顾及地面POS信息的城市实景三维重建方法,并使用此方法对佛山市历史文化街区进行了精细化建模。试验表明,与常规方法相比,该方法的模型效果好、效率高,对实景三维产品的生产与空间数据多尺度表达具有重要意义,可为数字孪生应用提供更精细的地理场景表现形式。

舰载POS MV数据采集与处理技术的水上定位性能

为提高水运工程复杂作业环境舰载水下声学设备的定位能力,研究了舰载POS MV系统组成单元及搭载的Applanix IN-Fusion GNSS INS组合定位基本原理。基于POSPac MMS构建了4种POS数据后处理模式选择策略及方法流程,形成了舰载POS数据采集与处理核心技术体系。依托温岭航道疏浚工程扫测项目开展离岸35 km持续2.17 h的POS MV WaveMaster数据采集及处理工程实践。研究结果表明:1)POS MV在非星站差分情况下,其实时定位平面、高程精度均为米级,横纵摇、艏向平均精度分别为0.026°、0.029°。2)在POSPac MMS的PP-RTX和SingleBase后处理模式下,平面、高程定位精度提高至2~3 cm,横摇、艏向平均精度分别提高至0.012°、0.015°,真垂荡数据中误差稳定在0.01 m。3)POS MV可以实时获取稳定、有效的惯导数据,辅助后处理技术能够为水运工程提供准确的位置和姿态信息。

POS支持下的构架航线定位精度探讨

垂直飞行于常规航线能够替代每条基本航线两端的高程控制点,可提高影像定位的高程精度。以附带POS数据的UCXp航空数字影像为例,探讨在区域四角基本航线与构架航线交叉的位置,布设野外像控点组,设计仅有影像姿态数据参与、仅有像控点参与、影像姿态数据+像控点共同参与等3种空中三角测量方案,用于检测1∶10000平地成图的加密精度。结果表明,影像姿态数据+像控点共同参与的加密方案,其成果平面精度较高,高程精度可以明显提高。

基于高精度POS的航摄无人机大比例尺测图精度分析

定位定姿系统辅助航空摄影测量能够有效减少像控点布测数量,提升作业效率。本文通过一套搭载高精度POS设备的无人机航摄系统对某地进行航空摄影测量和数据处理,分析了不同像控点数量对成图精度的影响,验证了该系统能够依靠高精度POS设备,实现1∶500比例尺无像控点测图的精度要求。

机载POS系统用于航空遥感直接对地目标定位的精度分析

利用实际航摄资料评价了WGS 84和国家80坐标系下机载POS(position and orientation system)系统直接对地目标定位的精度,分析了不同大地水准面拟合方法对高程精度的影响,检校了POS系统的视准轴误差,讨论了检校场的检校结果。试验表明,基于POS系统的航空遥感直接对地目标定位至少需要利用带有1个平高地面控制点的检校场对POS系统进行检校才能消除系统误差;在WGS84坐标系中,可以获得较高的定位精度,而转换到国家80坐标系下,必须对高程进行大地水准面拟合改正。

高斯-克吕格投影坐标系下POS角元素的转换方法

我国的地形测量坐标系通常采用高斯-克吕格投影坐标系,由于地球曲率和子午线偏差的影响,POS系统提供的传感器姿态角向影像外方位角元素的转换过程中存在误差,需要引入一个额外的补偿矩阵进行修正。从分析地球曲率和子午线偏差对影像外方位角元素的影响入手,推导补偿矩阵的严密计算公式,并完善了POS角元素的转换公式。通过对带有POS数据的实际航摄影像资料处理,验证补偿矩阵的正确性和实用性。试验结果表明,高斯-克吕格投影坐标系下POS外方位角元素的转换与中央经线的选取密切相关,与坐标原点的选取无关。利用补偿矩阵转换的影像外方位角元素精度明显高于POS系统提供值的精度。

基于POS数据的核线影像生成方法

提出一种对已知外方位元素的立体影像实施灰度重采样生成核线影像对的方法,推导了核线影像与原始影像之间的严密几何关系,并利用一组摄于某山区的1∶3000比例尺实际航空影像验证了所建立几何关系的正确性和方法的可行性。试验表明,利用光束法区域网平差和经检校后的POS影像外方位元素生成的核线影像对与基于常规相对定向方法所生成的核线影像对具有相同的质量,同名点的上下视差在1像元以内,完全可以满足摄影测量立体观测的要求;而采用未经检校的POS影像外方位元素所生成的同名核线影像对带有约70像元的上下视差,无法用于立体观测。

一种改进的高精度POS时间同步方法

结合现有时间同步方法及高精度POS的应用需求,提出了一种以GPS接收机输出的1PPS秒脉冲为基准,采用数字参数反馈方式,对惯性测量单元的数据采集脉冲周期进行实时修正的高精度POS时间同步方法,并给出了一种简易的POS时间同步精度测试方法。然后结合光纤陀螺POS实际系统进行了时间同步精度测试和对比实验。结果表明,所提出的时间同步方法能够克服时钟漂移并修正时间信号传输延迟,在保证工作可靠性的同时实现了在融合点上数据的高精度同步。

POS数据用于立体模型恢复时的上下视差分析

从连续法相对定向原理出发,推导了直接由像片外方位元素恢复立体模型时模型点上下视差的计算公式,用模拟数据验证了计算方法的正确性,并对两组不同摄影比例尺的实际航摄像片进行了试验。通过比较利用GPS辅助光束法区域网平差获得的像片外方位元素和POS提供的像片外方位元素重建立体模型所产生的模型上下视差,分析了POS系统误差对模型上下视差的影响。结果表明,直接利用POS提供的像片外方位元素进行安置元素测图会出现作业员难以忍受的模型上下视差,不能满足地形测图的规范要求。

基于双DSP的POS数据采集与处理系统的设计与实现

详细阐述了一种基于双DSP的POS数据采集与处理系统的设计与实现。该系统采用FPGA实现了IMU输出多路脉冲的并行采集和GPS数据的接收。通过专门的DSP1实现IMU的误差补偿和GPS数据解包,以及IMU和GPS数据的时间同步。采用高性能DSP2进行导航解算处理,两DSP之间通过并行主机接口(HPI)进行高速数据传输。所采集的IMU和GPS数据以及解算结果通过以太网接口输出。最后进行了跑车实验,实验结果表明:所研制的POS数据采集与处理系统在功能、精度及实时性方面均达到了预期的设计目标。

POS辅助航带间航摄影像的自动转点

提出一种利用POS提供的影像定向参数辅助区域航空摄影测量中航带间影像自动转点方法。首先,对航带内影像采用金字塔影像匹配策略寻求同名像点,以获得航向间影像连接点的精确像片坐标;然后利用POS提供的影像定向参数预测航带间的影像连接点。再通过对相邻航线间待匹配窗口影像的几何变形改正,在由POS数据辅助建立的核线几何条件约束下,直接在原始影像上找寻同名像点;最后经最小二乘匹配使影像匹配结果达到子像素级精度。试验表明,将POS数据引入航带间的影像自动转点中,不但可以简化影像匹配过程、提高自动化水平,而且较常规影像匹配方法可以提高航带间自动转点的成功率34.0%,并节省76.7%的CPU耗时。