共查询到19条相似文献，搜索用时 140 毫秒
1.
根据像底点与航摄像片外方位角元素的几何关系,本文提出利用像底点求解IMU视准轴误差,以提高POS系统直接对地目标定位精度的方法,并用一组实际飞行的数据进行了试验。结果表明,该方法可有效提高POS系统直接对地目标定位的精度,而无需布设特定的检校场和地面控制点。对带POS系统的城区大比例尺航空影像对地目标定位有一定实用价值。 相似文献
2.
POS数据用于立体模型恢复时的上下视差分析 总被引：1，自引：0，他引：1
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。 相似文献
3.
提出一种利用相机POS数据和少量影像数据标定倾斜相机间位置关系并计算倾斜影像粗略外方位元素的方法。首先对选取的垂直和倾斜影像进行影像匹配,获得精确同名点坐标;然后垂直影像同名点对前方交会获得地面点坐标,接着倾斜影像后方交会获得其外方位元素;最后利用倾斜和垂直影像的外方位元素标定子相机间的相对关系,并根据相对关系求出所有倾斜影像的外方位元素。采用AMC580倾斜影像数据进行试验,结果表明:提出方法可求得所有倾斜影像的粗略外方位元素,并验证了外方位元素的直接对地定位精度,证明了该方法的可行性。 相似文献
4.
基于已知定向参数影像的光束法区域网平差 总被引：1，自引：1，他引：1
从自检校光束法区域网平差模型出发,建立了利用同一地区已知定向参数的影像解求新获取影像外方位元素并进行目标定位的数学模型。以此为基础,对来自某地区相隔两年的三期不同摄影比例尺航空影像两两组合地进行联合光束法区域网平差。结果表明,当两期影像比例尺相近时,所解求的新影像外方位元素和加密点坐标精度基本达到常规光束法区域网平差的精度;当两期影像比例尺不同时,利用已知定向参数的大比例尺影像解求出的小比例尺影像的外方位元素和加密点坐标可满足现行规范精度要求,利用已知定向参数的小比例尺影像去解求大比例尺影像的外方位元素和加密点坐标精度明显下降且不可用。本文的研究证实,就同一地区的多时相航摄影像而言,利用已知定向参数的影像进行新影像的定向方法是可行的。 相似文献
5.
6.
7.
8.
9.
POS直接地理参考进行无控制、大比例尺测图可行性和能力一直被广泛关注。本文以863计划项目高精度轻小型航空遥感系统为平台,以其提供的高精度POS和宽角数码影像开展精度实验,提出了一种多层次组合精度验证方法,从POS输出与空三外方位的相关性、POS直接地理参考外方位与空三外方位比对精度、POS直接地理参考多片空间前方交会精度和直接立体测图精度等四个方面对POS无控制直接地理参考大比例尺测图的可行性和能力进行了验证,在JX-4数字摄影测量工作站下测得河南省平顶山市新华区的16幅1：500地形图,结合RTK实地测量检测验证测图精度。实验结果表明,高精度轻小型航空遥感系统POS直接地理参考可以满足无控制1：500大比例尺地形图测绘精度。 相似文献
10.
11.
机载POS系统用于航空遥感直接对地目标定位的精度分析 总被引：11，自引：0，他引：11
利用实际航摄资料评价了WGS84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。 相似文献
12.
通过机载POS辅助数码相机在大比例尺航空摄影测量中实际生产应用的成功案例重点介绍了POS系统误差检校,并分析了直接地理目标定位的实际精度. 相似文献
13.
ABSTRACT Geospatial information acquired with Unmanned Aerial Vehicles (UAV) provides valuable decision-making support in many different domains, and technological advances coincide with a demand for ever more sophisticated data products. One consequence is a research and development focus on more accurately referenced images and derivatives, which has long been a weakness especially of low to medium cost UAV systems equipped with relatively inexpensive inertial measurement unit (IMU) and Global Navigation Satellite System (GNSS) receivers. This research evaluates the positional accuracy of the real-time kinematics (RTK) GNSS on the DJI Matrice 600 Pro, one of the first available and widely used UAVs with potentially surveying-grade performance. Although a very high positional accuracy of the drone itself of 2 to 3 cm is claimed by DJI, the actual accuracy of the drone RTK for positioning the images and for using it for mapping purposes without additional ground control is not known. To begin with, the actual GNSS RTK position of reference center (the physical point on the antenna) on the drone is not indicated, and uncertainty regarding this also exists among the professional user community. In this study the reference center was determined through a set of experiments using the dual frequency static Leica GNSS with RTK capability. The RTK positioning data from the drone were then used for direct georeferencing, and its results were evaluated. Test flights were carried out over a 70 x 70 m area with an altitude of 40 m above the ground, with a ground sampling distance of 1.3 cm. Evaluated against ground control points, the planimetric accuracy of direct georeferencing for the photogrammetric product ranged between 30 and 60 cm. Analysis of direct georeferencing results showed a time delay of up to 0.28 seconds between the drone GNSS RTK and camera image acquisition affecting direct georeferencing results. 相似文献
14.
This work is aimed at the environmental remote sensing community that uses UAV optical frame imagery in combination with airborne and satellite data. Taking into account the economic costs involved and the time investment, we evaluated the fit-for-purpose accuracy of four positioning methods of UAV-acquired imagery: 1) direct georeferencing using the onboard raw GNSS (GNSSNAV) data, 2) direct georeferencing using Post-Processed Kinematic single-frequency carrier-phase without in situ ground support (PPK1), 3) direct georeferencing using Post-Processed Kinematic double-frequency carrier-phase GNSS data with in situ ground support (PPK2), and 4) indirect georeferencing using Ground Control Points (GCP). We tested a multispectral sensor and an RGB sensor, onboard multicopter platforms. Orthophotomosaics at <0.05 m spatial resolution were generated with photogrammetric software. The UAV image absolute accuracy was evaluated according to the ASPRS standards, wherein we used a set of GCPs as reference coordinates, which we surveyed with a differential GNSS static receiver. The raw onboard GNSSNAV solution yielded horizontal (radial) accuracies of RMSEr≤1.062 m and vertical accuracies of RMSEz≤4.209 m; PPK1 solution gave decimetric accuracies of RMSEr≤0.256 m and RMSEz≤0.238 m; PPK2 solution, gave centimetric accuracies of RMSEr≤0.036 m and RMSEz≤0.036 m. These results were further improved by using the GCP solution, which yielded accuracies of RMSEr≤0.023 m and RMSEz≤0.030 m. GNSSNAV solution is a fast and low-cost option that is useful for UAV imagery in combination with remote sensing products, such as Sentinel-2 satellite data. PPK1, which can register UAV imagery with remote sensing products up to 0.25 m pixel size, as WorldView-like satellite imagery, airborne lidar or orthoimagery, has a higher economic cost than the GNSSNAV solution. PPK2 is an acceptable option for registering remote sensing products of up to 0.05 m pixel size, as with other UAV images. Moreover, PPK2 can obtain accuracies that are approximate to the usual UAV pixel size (e.g. co-register in multitemporal studies), but it is more expensive than PPK1. Although indirect georeferencing can obtain the highest accuracy, it is nevertheless a time-consuming task, particularly if many GCPs have to be placed. The paper also provides the approximate cost of each solution. 相似文献
15.
16.
17.
基于机载POS辅助的直接地理定位系统,可得到平面与高程分别优于10和15 cm的中误差成果。但这一过程的实现对飞行环境和地面基站的依赖度较高,在实际工作中,不仅降低了生产效率,还增加了工作成本。基于虚拟参考基站理论和惯导辅助动态模糊度解算技术的紧耦合直接地理定位技术,摆脱了对飞行条件和基站距离的限制,在卫星失锁、地面基站距离超过70 km和无基站的情况下,仍能获取满足精度的解算结果。本文采用该技术对辽宁沈阳城区进行了高分辨率的数字航空遥感工作,通过对其数据的解算结果显示,采用机载POS紧耦合方案得到的数据精度要明显优于松散组合,在无基站的情况下采用的紧耦合单点精密解算所得到的成果也能满足相应的成果规范。 相似文献
18.
The topographic mapping products of airborne light detection and ranging (LiDAR) are usually required in the national coordinates (i.e., using the national datum and a conformal map projection). Since the spatial scale of the national datum is usually slightly different from the World Geodetic System 1984 (WGS 84) datum, and the map projection frame is not Cartesian, the georeferencing process in the national coordinates is inevitably affected by various geometric distortions. In this paper, all the major direct georeferencing distortion factors in the national coordinates, including one 3D scale distortion (the datum scale factor distortion), one height distortion (the earth curvature distortion), two length distortions (the horizontal-to-geodesic length distortion and the geodesic-to-projected length distortion), and three angle distortions (the skew-normal distortion, the normal-section-to-geodesic distortion, and the arc-to-chord distortion) are identified and demonstrated in detail; and high-precision map projection correction formulas are provided for the direct georeferencing of the airborne LiDAR data. Given the high computational complexity of the high-precision map projection correction approach, some more approximate correction formulas are also derived for the practical calculations. The simulated experiments show that the magnitude of the datum scale distortion can reach several centimeters to decimeters for the low (e.g., 500 m) and high (e.g., 8000 m) flying heights, and therefore it always needs to be corrected. Our proposed practical map projection correction approach has better accuracy than Legat’s approach,1 but it needs 25% more computational cost. As the correction accuracy of Legat’s approach can meet the requirements of airborne LiDAR data with low and medium flight height (up to 3000 m above ground), our practical correction approach is more suitable to the high-altitude aerial imagery. The residuals of our proposed high-precision map projection correction approach are trivial even for the high flight height of 8000 m. It can be used for the theoretical applications such as the accurate evaluation of different GPS/INS attitude transformation methods to the national coordinates. 相似文献
19.
机载POS系统视准轴误差检校 总被引：6，自引：3，他引：6
简要介绍了机载POS（position and orientaion system）系统视准轴误差检枝的基本原理和方法，建立了相应的数学模型，利用实际航摄影像资料验证了视准轴误差检校模型的正确性和可行性，并分析了利用其实施对地目标定位的精度。 相似文献