共查询到17条相似文献,搜索用时 140 毫秒
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飞机运动加速度的测量精度是制约航空重力测量技术发展的主要障碍之一。相较于传统动态差分GPS(differential GPS,DGPS)技术,所提方法采用单站测量模式,无需布设地面基准站。首先通过相位历元间差分解得高精度历元间位移序列,然后结合泰勒一阶中心差分获得载体加速度,重点分析了卫星轨道和卫星钟差对加速度估计的影响,结果表明,不同卫星轨道产品对加速度估计影响较小,而卫星钟差采样率对加速度估计的影响很大。结合中国陕西省境内的GT-2A航空重力测量系统飞行实测数据,利用单站法解算的加速度联合重力和姿态数据解算重力扰动结果与DGPS解算的重力扰动符合较好,当滤波长度为100 s时,两者互差优于1.0 mGal。重力扰动交叉点不符值网平差后,均方根(root mean square,RMS)为1.13 mGal。与地面重力实测值比较的结果表明,所提方法与DGPS方法在精度上基本一致,说明单站法标量航空重力测量是可行的。 相似文献
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VOR系统是目前国际民航组织采用的一种飞机标准近程导航系统,阐述了差分GPS(DGPS)在VOR信标台校飞中应用的有关问题,介绍了利用DGPS评定其方位精度,作用距离与顶空盲区的方法。 相似文献
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IMU/DGPS辅助的大跨度航线区域网平差精度分析 总被引:1,自引:0,他引:1
试验无控制和稀少控制条件下IMU/DGPS辅助的大跨度航线区域网平差,讨论IMU/DGPS辅助的大跨度航空摄影测量的精度情况;并通过与传统空中三角测量的对比,分析IMU/DGPS辅助的航测技术在节省外业控制方面的优势。 相似文献
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《测绘科技情报》2006,(1)
通常对航空测量来说山区的"恶劣的天气"是正常情况。只有在异常好的天气的情况下垂直航空摄影才可以顺利进行。Alaska的沿海山地的天气严重地阻碍测量的进行。为解决测量飞行的条件远不及理想天气的难题,我们提出了一种方法,目前正联合USGS冰河学部门在费尔班克斯,Alaska进行实验。当前主要研究一种新的其实质相当于高山地形学的方法,高山地形学应用近景遥感方法利用低飞行轻型飞机进行数字倾斜航空摄影测量。目前利用专业相机和多影像摄影测量系统以倾斜航空摄影的方式可以提取DEM(数字高程模型),几乎任何敞开窗户的轻型飞机都可以进行这种倾斜摄影。由于采用这种方式飞机不需要直的飞行航线,可以自由的在目标区域上空和周围飞行。这样飞机就可以与空间目标十分接近,获得非常高精度,精度取决于目标的大小和目标与飞机的距离。更重要的是垂直摄影和"山脉飞行"在任何天气都能够获得数据。这种飞行方式对天气的限制条件很少,这一点与垂直航空摄影方式不同,垂直航空摄影要求碧空,无云,但空中强热流使得这些条件无法满足。尤其是针对海洋高山天气环境这种方法占有优势,由于天气条件造成的延误大大减少了。依赖目标区域位置,低空山谷内部和接近摄影目的地的飞行是垂直的。以这种方法云下飞行,并围绕目标且从目标的各个方向以获得测量图像。如果天气允许,可以使用垂直图像并且成为系统的一部分。通常精度与垂直航空相机水平和航摄员摄影水平有关。目前数字多影像摄影测量的自动表面测量的方法是可行的,并获得质量好的结果。相机与DGPS和INS的结合获得近似的相机位置,使得无需测量目标位置的地面控制点(GCP's)。 相似文献
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部分利用DGPS技术的移动激光扫描系统的点云数据质量很大程度上受移动轨迹的解算精度影响。针对DGPS必须架设基站的局限性,以背负式移动激光扫描系统为例,使用精密单点定位(precise point positioning, PPP)技术对背负式激光扫描系统的移动轨迹进行解算并进行PPP内符合精度分析。文中通过GPS-RTK分别对PPP与DGPS辅助获取的点云数据精度进行检测,将两种技术获取的点云数据精度进行对比分析。试验结果表明:利用PPP辅助获取点云数据精度与DGPS辅助获取点云数据精度相当,PPP代替DGPS应用于背负式移动激光扫描系统完全是可行的。 相似文献
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结合SAR成像原理,在提出了基于DGPS/IMU数据的机载InSAR系统DEM三维坐标求解的基础上,推导出了基线长度、基线倾角、相位差、雷达天线到地面目标点的距离、雷达天线位置、中心多普勒频率及飞机飞行速度等因素误差对DEM精度的影响公式,分析讨论了机载InSAR系统影响精度的主要因素及系统可实现的性能情况,提出了机载InSAR系统部分设计建议,并使用实际的机载InSAR数据进行了试验。结果表明,本方法结果与实际试验统计的精度基本一致,影响精度的分析结论正确。 相似文献
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A combined algorithm of improving INS error modeling and sensor measurements for accurate INS/GPS navigation 总被引:1,自引:1,他引:1
Although the integrated system of a differential global positioning system (DGPS) and an inertial navigation system (INS)
had been widely used in many geodetic navigation applications, it has sometimes a major limitation. This limitation is associated
with the frequent occurrence of DGPS outages caused by GPS signal blockages in certain situations (urban areas, high trees,
tunnels, etc.). In the standard mechanization of INS/DGPS navigation, the DGPS is used for positioning while the INS is used
for attitude determination. In case of GPS signal blockages, positioning is provided using the INS instead of the GPS until
satellite signals are obtained again with sufficient accuracy. Since the INS has a very short-time accuracy, the accuracy
of the provided INS navigation parameters during these periods decreases with time. However, the obtained accuracy in these
cases is totally dependent on the INS error model and on the quality of the INS sensor data. Therefore, enhanced navigation
parameters could be obtained during DGPS outages if better inertial error models are implemented and better quality inertial
measurements are used. In this paper, it will be shown that better INS error models are obtained using autoregressive processes
for modeling inertial sensor errors instead of Gauss–Markov processes that are implemented in most of the current inertial
systems and, on the other hand, that the quality of inertial data is improved using wavelet multi-resolution techniques. The
above two methods are discussed and then a combined algorithm of both techniques is applied. The performance of each method
as well as of the combined algorithm is analyzed using land-vehicle INS/DGPS data with induced DGPS outage periods. In addition
to the considerable navigation accuracy improvement obtained from each single method, the results showed that the combined
algorithm is better than both methods by more than 30%. 相似文献
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Space born systems like Geoscience Laser Altimeter System (GLAS) onboard collect data for ice, cloud and Land. Elevation satellite
(ICESat) collects an unparalleled data set as waveform over terrestrial targets, helps in evaluating the global elevation
data. In this study we compared the Digital Elevation Surface (DES) generated by Cartosat-1 point data and DES generated by
merging the Cartosat-1 data with ICESat data. Outputs in the form of interpolated surfaces were evaluated with the help of
differential global positioning system (DGPS) points collected from study area. The study showed the results that the DES
generated from Cartosat — 1 data had less elevation accuracy when compared with the DGPS data. While merging Cartosat-1 point
height data with ICESat/GLAS data resulted in better accuracy. On the practical side for processing the interpolation, based
on the research the ICESat /GLAS with Cartosat-1 height data can produce better DES compared to the Cartosat-1 stereo data.
The DES was generated using geostatistical interpolation methods in which the global polynomial method proved to be the better
for generating the surface compare to other interpolation techniques studied in this work. For co-kriging method, the accuracy
decreases compare to the kriging interpolation, due to the complexity of parameters that were used for interpolation. On the
theory side, based on this research the statement of which interpolation technique is better than the other cannot be mentioned
easily, because these are based on the data type, parameters and also on method of interpolation. So research experiment should
be more intensely and with more focused. 相似文献
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Precise aircraft single-point positioning using GPS post-mission orbits and satellite clock corrections 总被引:3,自引:0,他引:3
Summary Aircraft single point position accuracy is assessed through a comparison of the single point coordinates with corresponding DGPS-derived coordinates. The platform utilized for this evaluation is a Naval Air Warfare Center P-3 Orion aircraft. Data was collected over a period of about 40 hours, spread over six days, off Florida's East Coast in July 94, using DGPS reference stations in Jacksonville, FL, and Warminster, PA. The analysis of results shows that the consistency between aircraft single point and DGPS coordinates obtained in single point positioning mode and DGPS mode is about 1 m (rms) in latitude and longitude, and 2 m (rms) in height, with instantaneous errors of up to a few metres due to the effect of the ionosphere on the single point L1 solutions. 相似文献