排序方式： 共有104条查询结果，搜索用时 15 毫秒
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低空摄影测量无人机稳定性较差,因此掌握无人机的气动参数,对于无人机的稳定性评佑和改进,航空摄影参数纠正等都有重要意义.通过差分全球定位系统和EKF技术计算无人机气动参数,对于设计无人机的气动外形,计算无人机负载和摄影参数等,都有较高的应用价值.本文通过实验中DGPS差分机和光学追踪系统比较分析,计算无人机导航精度,同时... 相似文献
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The vegetation communities and spatial patterns on the Fire Island National Seashore are dynamic as the result of interactions with driving forces such as sand deposition, storm-driven over wash, salt spray, surface water, as well as with human disturbances. We used high spatial resolution QuickBird-2 satellite remote sensing data to map both terrestrial and submerged aquatic vegetation communities of the National Seashore. We adopted a stratified classification and unsupervised classification approach for mapping terrestrial vegetation types. Our classification scheme included detailed terrestrial vegetation types identified by previous vegetation mapping efforts of the National Park Service and three generalized categories of high-density seagrass, low-density seagrass coverages, and unvegetated bottom to map the submerged aquatic vegetation habitats. We used underwater videography, GPS-guided field reference photography, and bathymetric data to support remote sensing image classification and information extraction. This study achieved approximately 82% and 75% overall classification accuracy for the terrestrial and submnerged aquatic vegetations, respectively, and provided an updated vegetation inventory and change analysis for the Northeast Coastal and Barrier Network of the National Park Service. 相似文献
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本文简要论述了差分ＧＰＳ的基本原理，对我所从法国ＤＳＮＰ公司引进的ＮＤＳ２００ＬＲ远距离差分ＧＰＳ系统进行了简单的介绍。 相似文献
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高精度全球差分GPS的应用 总被引：9，自引：0，他引：9
差分GPS（包括DGPS，RTK，LCDGPS，WADGPS等）已取得了长足的长展，并能在数个星基内实现。随着空间科学技术的发展和其后任务的需要，迫切要求解决全球范围内的无缝对接，因此，实现高精度全球差分GPS已成为当前GPS研究的一大课题。本文以喷气推进实验室的研究为例，讨论了其基本内容、技术路线及关键技术。 相似文献
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China is arguably one of the countries where the most tunneling and underground projects are being performed. Recently in China, it has often been necessary to construct tunnels under many types of conditions and to develop new techniques. Currently, some advanced construction techniques cannot be appropriately applied to different types of underground conditions, and many traditional methods are still often used. However, because of the progress in tunnel boring machines (TBM), innovations are required for the construction method. This article introduces the current situation of TBM both in western countries and in China, and examines the future of TBM in China. 相似文献
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A comparison of stable platform and strapdown airborne gravity 总被引：3，自引：1，他引：2
C. L. Glennie K. P. Schwarz A. M. Bruton R. Forsberg A. V. Olesen K. Keller 《Journal of Geodesy》2000,74(5):383-389
To date, operational airborne gravity results have been obtained using either a damped two-axis stable platform gravimeter
system such as the LaCoste and Romberg (LCR) S-model marine gravimeter or a strapdown inertial navigation system (INS), showing
comparable accuracies. In June 1998 three flight tests were undertaken which tested an LCR gravimeter and a strapdown INS
gravity system side by side. To the authors' knowledge, this was the first time such a comparison flight was undertaken. The
flights occurred in Disko Bay, off the west coast of Greenland. Several of the flight lines were partly flown along existing
shipborne gravity profiles to allow for an independent source of comparison of the results. The results and analysis of these
flight tests are presented. The measurement method and error models for both the stable platform and strapdown INS gravity
systems are presented and contrasted. An intercomparison of gravity estimates from both systems is given, along with a comparison
of the individual estimates with existing shipborne gravity profiles. The results of the flight tests show that the gravity
estimates from the two systems agree at the 2–3 mGal level, after the removal of a linear bias. This is near the combined
noise level of the two systems. It appears that a combination of both systems would provide an ideal airborne gravity survey
system, combining the excellent bias stability of the LCR gravimeter with the higher dynamic range and increased spatial resolution
of the strapdown INS.
Received: 3 June 1999 / Accepted: 30 November 1999 相似文献