scholarly journals In‐orbit geometric calibration approach and positioning accuracy analysis for the Gaofen‐7 laser footprint camera

2021 ◽  
Author(s):  
Junfeng Xie ◽  
Chaofeng Ren ◽  
Huihui Jiao ◽  
Jianping Pan
Keyword(s):  
Accuracy Analysis ◽  
Positioning Accuracy ◽  
Geometric Calibration ◽  
Calibration Approach

Spatial positioning accuracy analysis of intelligent laser 3D projection

2018 ◽  
Vol 47 (8) ◽  
pp. 806006
Author(s):  
郭丽丽 Guo Lili ◽  
李丽娟 Li Lijuan ◽  
侯茂盛 Hou Maosheng ◽  
林雪竹 Lin Xuezhu
Keyword(s):  
Accuracy Analysis ◽  
Positioning Accuracy ◽  
Spatial Positioning

scholarly journals Improvement and Assessment of the Absolute Positioning Accuracy of Chinese High-Resolution SAR Satellites

2019 ◽  
Vol 11 (12) ◽  
pp. 1465
Author(s):  
Deng ◽  
Zhang ◽  
Cai ◽  
Xu ◽  
Zhao ◽  
...  
Keyword(s):  
High Resolution ◽  
Propagation Delay ◽  
Reference Points ◽  
Calibration Model ◽  
Land Resource ◽  
Positioning Accuracy ◽  
Geometric Calibration ◽  
Atmospheric Propagation ◽  
Absolute Positioning ◽  
The Absolute

In recent years, China has launched YaoGan-13 and GaoFen-3, high-resolution synthetic aperture radar (SAR) satellites that can acquire global high-resolution images. The absolute positioning accuracy of such satellites is important for mapping areas without ground reference points and for automated processing. However, satellites without geometric calibration have poor absolute positioning accuracy, greatly restricting their application (e.g., land resource surveys). Therefore, they cannot meet national demands for high-resolution SAR images with good geometric accuracy. Here, we propose a series of methods to improve the absolute positioning accuracy of YaoGan-13 and GaoFen-3, such as the multiple-image combined calibration strategy and geometric calibration model for a real continuously moving configuration, including consideration of atmospheric propagation delay. Using high-accuracy ground control data collected from different areas, the 2-D and 3-D absolute positioning accuracies of YaoGan-13 and GaoFen-3 were assessed after implementation of the improvement measures. Experimental results showed that, after calibration, the 2-D absolute positioning accuracy of YaoGan-13 and GaoFen-3 are improved from 43.86 m to 2.57 m and from 30.34 m to 4.29 m, respectively. In addition, the 3-D absolute positioning accuracies of YaoGan-13 in plane and elevation are 3.21 m and 2.22 m, respectively. Improving the absolute positioning accuracy of these satellites could broaden the scope of their potential applications in the future.

scholarly journals Study on Telescope Gain Affected by a Multilevel Hybrid Mechanism in FAST

2014 ◽  
Vol 6 ◽  
pp. 841526 ◽  
Author(s):  
Xiaoming Chai ◽  
Jin Fan ◽  
Lanchuan Zhou ◽  
Bo Peng
Keyword(s):  
Radio Telescope ◽  
Physical Meaning ◽  
Error Model ◽  
Geometric Errors ◽  
Accuracy Analysis ◽  
Positioning Error ◽  
Error Sources ◽  
Positioning Accuracy ◽  
Hybrid Mechanism ◽  
Structural Deformations

This paper focuses on the telescope gain affected by a multilevel hybrid mechanism for the feed positioning in the five-hundred-meter aperture spherical radio telescope (FAST) project, which is based on the positioning accuracy analysis of the mechanism. First, error model for the whole mechanism is established and its physical meaning is clearly explained. Then two kinds of error sources are mainly considered: geometric errors and structural deformations. The positioning error over the mechanism's workspace is described by an efficient and intuitive approach. As the feed position error will lower the telescope gain, this influence is analyzed in detail. In the end, it is concluded that the design of the mechanism can meet the requirement of the telescope performance.

scholarly journals INVESTIGATION OF PRACTICAL AND THEORETICAL ACCURACY OF WIRELESS INDOOR POSITIONING SYSTEM UBISENSE

2013 ◽  
Vol 95 (1) ◽  
pp. 36-48 ◽  
Author(s):  
Marek Woźniak ◽  
Waldemar Odziemczyk ◽  
Kamil Nagórski
Keyword(s):  
Reference Points ◽  
Positioning System ◽  
Accuracy Analysis ◽  
Positioning Accuracy ◽  
Test Measurement ◽  
Calibration Accuracy ◽  
Indoor Positioning System ◽  
Orientation Parameters ◽  
Measurement Area ◽  
Theoretical Accuracy

Abstract This paper presents the accuracy investigation results and functionality of Ubisense RTLS positioning system. Three kinds of studies were conducted: test of calibration accuracy, analysis of theoretical accuracy of the coordinates determination as well as accuracy measurements in field conditions. Test of calibration accuracy was made with several different geometric constellation of reference points (tag positions). We determined changes of orientation parameters of receivers and disturbance of positioning points coordinates against chosen reference points constellations. Analysis of theoretical accuracy was made for several receivers spatial positions and their orientations. It allowed to indicate favourable and unfavourable measurement area considering accuracy and reliability. Real positioning accuracy of the Ubisense system was determined by comparison with coordinates measured using precise tacheometer TCRP1201+. Results of conducted experiments and accuracy analysis of test measurement were presented in figures and diagrams.

Evaluation of 3D Geo-Positioning Based on Bias-Compensated RPCs for Across-Track QuickBird Stereo Imagery

2012 ◽  
Vol 226-228 ◽  
pp. 1958-1964
Author(s):  
Weian Wang ◽  
Shu Ying Xu ◽  
Gang Qiao
Keyword(s):  
Vertical Direction ◽  
Ground Control ◽  
Control Points ◽  
Accuracy Analysis ◽  
Geometric Correction ◽  
Positioning Accuracy ◽  
Ground Control Points ◽  
Order Polynomial ◽  
Stereo Imagery ◽  
Very High

This paper investigates the geo-positioning accuracy of across-track QuickBird stereo imagery in Shanghai, China, where the terrain relief is very low about 3m but with very high buildings up to 380m. The rational function model (RFM) and the bias-compensated RFM with different parameters are employed to do accuracy analysis with different configurations of ground control points (GCPs). The systematic errors in vendor provided RPCs are revealed and discussed. The results of bias-compensated RFM show that different strategies in terms of the number of GCP and different geometric correction methods should be taken into consideration in order for a better and reasonable positioning accuracy in the three directions. The results also show that the best accuracy of 0.6m in horizontal direction and 0.8m in vertical direction can be acquired by the second-order polynomial model when GCPs are more than 8.

scholarly journals ACCURACY ANALYSIS OF THE SATELLITE POSITIONING BY USING GNSS REFERENCE STATIONS

2020 ◽  
pp. 350-354
Author(s):  
A.U. Chymyrov ◽  
Sh.S. Sargazakova ◽  
N.Y. Ismailov
Keyword(s):  
Accuracy Analysis ◽  
Satellite Measurements ◽  
Positioning Accuracy ◽  
Satellite Positioning ◽  
Control Centre ◽  
Gnss Receivers

The technology of satellite positioning by using RTK service by the KyrPOS -Control Centre of CORS Network is studied in this article. Differentially corrected satellite measurements with geodetic class GNSS receivers were done and their positioning accuracy was analyzed.

A geometric calibration approach for industrial cone-beam CT system based on low-rank phantom

2021 ◽  
Author(s):  
Jianqiao Yu ◽  
Jian Lu ◽  
Yi Sun ◽  
Jishun Liu ◽  
Kai Cheng
Keyword(s):  
Cone Beam Ct ◽  
Calibration Method ◽  
Low Rank ◽  
Cone Beam ◽  
Ball Bearings ◽  
Geometric Calibration ◽  
System A ◽  
Ct System ◽  
Local Image ◽  
Calibration Approach

Abstract Precise alignment of the system scan geometry is crucial to ensure the reconstructed image quality in the cone-beam CT system. A calibration method that depends on the local feature of ball bearings phantom and point-like markers is probably affected by local image variations. Besides, multiple projections with circular scanning are usually required by this type of method to derive misaligned parameters. In contrast to previous works, this paper proposes a method that depends on the global symmetric low-rank feature of a novel phantom, which can accurately represent the system geometrical misalignment. All the misaligned parameters of the cone-beam CT system can be estimated from a single perspective direction without circular scanning. Meanwhile, since the global low-rank feature of the phantom is utilized, the proposed method is robust to the noise. Extensive simulations and real experiments validate the accuracy and robustness of our method, which achieves better performance compared to an existing phantom-based method.

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