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重点围绕远程飞行器飞行轨道控制保障需求,开展了空中扰动引力计算和地面重力异常测量精度指标及海洋重力测量测线布设方案的分析与论证。首先通过解析和简化飞行器导航误差解表达式,定量估计了地球重力场对远程飞行器飞行轨迹的影响,并以一定量值的落点偏差为限定指标,研究论证了空中扰动引力的计算精度要求。在此基础上,通过对地面重力异常截断误差及数据传播误差的估计和分析,研究确定了地面/海面网格平均重力异常的观测分辨率和计算精度指标。以此为依据,提出了相对应的海洋重力测量测线布设方案,并通过数值计算验证了所提方案的合理性和有效性。 相似文献
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计算了发射点位于全国范围内、经度纬度各相差5°、均匀分布的40个点的洲际弹道导弹被动段的扰动引力,分析了扰动引力对导弹落点的影响;绘制了落点偏差等值线图.结果表明:发射点位于我国西部地区时,扰动引力引起导弹被动段的落点偏差最大.通过分析扰动引力系统误差和随机误差对导弹被动段落点的影响,得出了扰动引力误差对导弹被动段落点的影响量级. 相似文献
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结合某高速公路高挡墙段沉降监测数据,研究了趋势拟合和时序分析综合模型预报在高挡墙沉降预报中的适用性,提供了一种简便易行的、可供一般工程人员使用的趋势拟合和时序分析综合模型计算方案。 相似文献
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交通拥堵是当代各大城市普遍面临的问题,如何通过各种技术手段发现城市交通的易拥堵路段并予以改善是城市交通相关部门以及学者关心的一个问题。通过各种GPS设备产生的历史轨迹数据对城市的研究逐渐受到重视,且取得一定的进展。文中总结运行车辆的4种通行状态:正常行驶、停靠/停泊、信号灯等待以及拥堵,分析这4种状态下运行车辆的速度特征,定义轨迹段平均速度和轨迹段速度方差两个数字特征用来描述运行车辆轨迹段的速度特征以及描述路段拥堵程度的拥堵指数,提出一种基于轨迹分段的拥堵检测的可视化方法,通过实验验证发现其可以较好地估计城市交通拥堵状况。 相似文献
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中国大陆构造环境监测网络由260个连续全球定位系统观测站点和2 000个不定期全球定位系统观测站点构成,一般采用GAMIT或Bernese高精度数据处理软件进行处理。由于GAMIT及Bernese软件对测站数处理能力的限制,必须对陆态网连续运行基准站进行分区解算。针对这一问题,为研究不同分区方案对陆态网解算精度的影响,该文基于全国55个陆态网络连续运行基准站数据,采用整网解算方案以及间距分区法和区域子网划分法分别进行解算,并以整网解算结果作为标准值,对比两种分区方案与整网解算方案的基线长度差及坐标差。结果表明,间距分区方案解算精度比区域子网划分方案精度高,可实现对陆态网分区的高精度解算。最后利用间距分区法对全国240个陆态网络连续运行基准站进行分区解算,得到了较高精度的解算结果。 相似文献
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准确预报地球自转变化对于精密定位、空间飞行器的跟踪与正常运行,具有重要的科学意义和实用价值。根据周日变化（UT1-UTC）和极移变化（PM）的特性,用最小二乘法,建立了适合于UT1-UTC和PM趋势项和周期项观测数据的拟合模型。对于UT1-UTC残差序列采用差分自回归移动平均（ARIMA）模型进行预报,对于PM残差采用季节性自回归移动平均（SARMA）模型进行预报。实例结果表明：我们的UT卜UTC预报结果比地球自转服务（IERS）产品好,而PM比IERS要差一些。当大气角动量（AAM）和海洋角动量（OAM）数据参与计算后,对UT卜UTC的预报有细微改善,对PM无改善。 相似文献
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一种利用改进A*算法的无人机航迹规划 总被引：2，自引：0，他引：2
提出了一种改进的A*算法解决大范围三维战场环境的无人机航迹规划问题。针对低空突防中无人机需满足生存率高、耗油量小等要求,算法综合考虑了航线高度、被探测概率、航线长度等权重因子,在该目标空间中搜索一条两个航路点之间的最优航线。同时为了满足UAV安全高度、升降率、转弯半径等性能约束,提出了一系列航线优化算法,得到最终的可飞航线。 相似文献
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仿地飞行对于无人机航测至关重要,能否相对地面保持稳定的航高直接关系到无人机在复杂地形区域的安全性和数据质量问题。本文提出一种基于单目视觉的无人机航高估计方法,通过光流法对无人机实时获取的视频进行跟踪和分析,提取运动信息以估算实时航高。试验结果表明,该方法能够快速、准确地估算无人机实时航高,在没有地表高程信息的情况下实现了自动仿地飞行。 相似文献
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Jan Skaloud Philipp Schaer Yannick Stebler Phillip Tomé 《ISPRS Journal of Photogrammetry and Remote Sensing》2010,65(2):208-217
This paper presents a methodology for the precise registering of airborne laser data directly in flight with an accuracy that is sufficient for the majority of derived products, such as digital terrain models. We first present the strategy that integrates GPS/INS/LiDAR data for generating laser point clouds directly in flight and analyzes their accuracy. The latter requires the implementation of a functional covariance propagation on-line for all the system components (i.e. trajectory, laser, system calibration) to which influences of scanning geometry are added at the end of a flight line. The study of scanning geometry necessitates the classification of vegetation and coarse estimation of the terrain normal. This is achieved by a method that we formerly proposed for off-line quality analysis. The second part of the paper focuses on the positioning component. In high resolution scanning performed close to the terrain, the absolute accuracy of the resulting point cloud depends mainly on the quality of the trajectory which is related to the type of GPS solution (e.g. absolute positioning, DGPS, RTK). To reach sub-decimeter accuracy for the point cloud in the real-time, an RTK-GPS solution is needed. This requires the establishment of a communication link for the transmission of GPS corrections (or measurements). We analyze the usability of RTK-GPS/ALS acquired during several flights using different communication methods in the particular context of helicopter based missions. We focus mainly on the exploitation of nation-wide reference GNSS networks and confirm experimentally that the real-time registration of airborne laser data is feasible with sub-decimeter accuracy. Such quality is sufficient not only for a wide range of applications, but it also opens new opportunities for monitoring missions that require a short reaction time. Finally, we concentrate on situations when the phase and code corrections cannot be transmitted, and the quality of the differential carrier-phase positioning needs to be predicted. We validate the previously introduced indicators of positioning quality by simulated degradation of the input data. 相似文献
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针对无人机倾斜摄影技术受遮挡影响较大和难以穿透植被茂密地区的问题,本文提出了城市复杂地形环境下倾斜模型结合LiDAR点云进行小区域大比例尺数字地形图的更新方法。首先采用五镜头六旋翼无人机分别以垂直和平行主要建筑物楼群方向进行2次全区域拍摄,以及无人机机载激光雷达全区域采集点云,并对高度不足10 m的别墅区进行单镜头低空补飞。然后融合倾斜影像点云与机载激光点云建模,经过3种建模方案对比,融合建模的倾斜三维模型的位置精度和模型质量均最优。最后基于此模型进行测图。精度评定结果表明,城市复杂地形环境下在飞行方案和像控点布设合理的情况下,通过倾斜三维模型采集的数字地形图的平面和高程精度完全满足并优于深圳市1∶1000数字地形图动态更新的精度指标。 相似文献
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本文为低空无人机平台弱控制航摄影像建立符合航测处理要求的区域网,提出了基于无人机飞控数据的无人机影像航带整理技术;分析了无人机影像航测处理区域网构建要求,提出针对无人机航测处理的航带整理技术流程;设计了基于飞控姿态数据的无人机起降和转弯影像自动剔除算法,自动生成航带;并提出了基于飞控数据快速计算像片FOV算法,构建区域网内像对链接关系;对实际无人机航摄的两个测区进行航带整理实验,结果表明基于飞控数据可快速构建区域网,满足空三匹配和挑片测图要求。 相似文献
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GOCE orbit predictions for SLR tracking 总被引：1，自引：0，他引：1
After a descent phase of about half a year, the Gravity field and steady-state Ocean Circulation Explorer (GOCE) reached the
final orbital altitude of the first measurement and operational phase (MOP-1) in September 2009. Due to this very low orbital
altitude and the inactive drag compensation during descent, the generation of reliable predictions of the GOCE trajectory
turned out to be a major challenge even for short prediction intervals. As predictions of good quality are a prerequisite
for frequent ranging from the tracking network of the International Laser Ranging Service (ILRS), Satellite Laser Ranging
(SLR) data of GOCE was very sparse at mission start and made it difficult to independently calibrate and optimize the orbit
determination based on data of the Global Positioning System (GPS). In addition to the GOCE orbit predictions provided by
the European Space Agency (ESA), the Astronomical Institute of the University of Bern (AIUB) started providing predictions
on July 22, 2009, as part of the Level 1b to Level 2 data processing performed at AIUB. The predictions based on the 12-h
ultra-rapid products of the International GNSS Service (IGS) were originally intended to primarily serve the daylight passes
in the early evening hours over Europe. The corresponding along-track prediction errors were often kept below 50 m during
the descent phase and allowed for the first successful SLR tracking of GOCE over Europe on July 29, 2009, by the Zimmerwald
observatory. Additional predictions based on the IGS 18-h ultra-rapid products are provided by AIUB since September 20, 2009,
to further optimize the GOCE SLR tracking. In this article, the development of the GOCE prediction service at AIUB is presented,
and the quality of the orbit predictions is assessed for periods with and without active drag compensation. The prediction
quality is discussed as a function of the prediction interval, the quality of the input products for the GPS satellite orbits
and clocks, and the availability of the GOCE GPS data. From the methodological point of view, different approaches for the
treatment of the non-gravitational accelerations acting on the GOCE satellite are discussed and their impact on the prediction
quality is assessed, in particular during the descent phase. Eventually, an outlook is given on the significance of GOCE SLR
tracking to identify systematic errors in the GPS-based orbit determination, e.g., cross-track errors induced by mismodeled
GOCE GPS phase center variations (PCVs). 相似文献
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随着弹道导弹系统技术的不断改进,影响导弹精度的工具类误差已逐渐降低,地球重力场扰动引力已经成为影响导弹命中精度的主要因素。这里从3个方面分析了扰动引力对弹道的影响,模拟结果表明,对于射程为10000 km以上的远程导弹,扰动引力的影响会造成超过1 km的落点偏差;5×10-5m s-2的扰动引力系统性偏差对导弹落点有明显影响。因此,扰动引力对导弹落点的影响不容忽视。 相似文献
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出租车GPS轨迹集聚和精细化路网提取 总被引：1，自引：1，他引：0
针对利用GPS数据提取双向路网和交叉路口转向信息精度低的不足,本文提出一种顾及位置与行驶方向的轨迹集聚和精细化路网提取方法,实现了精细化路网提取。为提高交叉路口路网的提取精度,首先剔除原始轨迹中的离散和异常轨迹点,并按一定的步长对轨迹段进行加密;然后引入行驶方向角来表达车辆在轨迹点处的行驶方向,顾及位置和行驶方向获取每个轨迹点的相似轨迹点集合;接着依次计算每个轨迹点的偏移距离,通过对轨迹点的迭代偏移完成轨迹集聚;最后剔除未成功集聚的轨迹点,将完成集聚的轨迹点连成轨迹线并作缓冲区,运用栅格数据数字化方法提取得到能够反映道路精细转向关系的道路网。以福州市出租车GPS数据进行轨迹集聚和路网提取试验,结果表明:本文方法能有效地将GPS轨迹按车辆行驶方向分别进行集聚,提取的道路网为双向道路并且能反映交叉路口处道路的精细转向关系。 相似文献
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景像匹配仿真的一种新方法 总被引：3，自引：0，他引：3
分析了影响景像相关匹配精度的各种误差因素，并给出它们的误差仿真模型，该模型可以适应飞行姿态、飞行器特性，天候等条件变化时的匹配概率估计，并可以与图像特征参数分析方法相结合。实验验证了该模型的有效性，且可以快速地给出影像图的适配性估计图，用于飞行器的航迹规划。 相似文献