scholarly journals Optical Image Generation and High-precision Line-of-Sight Extraction for Mars Approach Navigation – CORRIGENDUM

2018 ◽  
Vol 72 (1) ◽  
pp. 253-254 ◽  
Author(s):  
Xiuqiang Jiang ◽  
Shuang Li ◽  
Long Gu ◽  
Jun Sun ◽  
Dongdong Xiao
Keyword(s):  
High Precision ◽  
Optical Image ◽  
Line Of Sight ◽  
Image Generation

scholarly journals Optical Image Generation and High-precision Line-of-Sight Extraction for Mars Approach Navigation

2018 ◽  
Vol 72 (1) ◽  
pp. 229-252 ◽  
Author(s):  
Xiuqiang Jiang ◽  
Shuang Li ◽  
Long Gu ◽  
Jun Sun ◽  
Dongdong Xiao
Keyword(s):  
High Precision ◽  
Level Line ◽  
Simulation System ◽  
Optical Image ◽  
Least Square ◽  
Line Of Sight ◽  
Image Generation ◽  
Image Simulation ◽  
Extraction Algorithm ◽  
Generation Procedure

A high-precision line-of-sight extraction technique is essential for autonomous optical navigation during the Mars approach phase. To support future Mars exploration missions, an optical image simulation system is a necessary ground verification facility for Mars image generation and line-of-sight extraction algorithm tests. In this paper, an optical image generation procedure is first developed according to projection relationships, reference flight profiles and camera parameters. Next, a hybrid image processing and subpixel-level line-of-sight extraction algorithm is proposed through modification of moment-based sub-pixel edge detection and improvement of direct least-square fitting approaches. Finally, an optical image simulation system is established, and the experimental results show that the proposed procedure can effectively simulate the optical image in the field-of-view of a Mars spacecraft, and the hybrid extraction algorithm can obtain high-precision Mars centroid information.

Underwater high-precision panoramic 3D image generation

2020 ◽  
Author(s):  
Zhaolun Li ◽  
Rushi Lan ◽  
Zhuo Chen ◽  
Xiaonan Luo ◽  
Ji Li ◽  
...  
Keyword(s):  
High Precision ◽  
Image Generation ◽  
3D Image

scholarly journals Densified Pupil Spectrograph as High-precision Radial Velocimetry: From Direct Measurement of the Universe’s Expansion History to Characterization of Nearby Habitable Planet Candidates

2022 ◽  
Vol 163 (2) ◽  
pp. 63
Author(s):  
Taro Matsuo ◽  
Thomas P. Greene ◽  
Mahdi Qezlou ◽  
Simeon Bird ◽  
Kiyotomo Ichiki ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Direct Measurement ◽  
High Precision ◽  
Resolving Power ◽  
Line Of Sight ◽  
High Dispersion ◽  
Velocity Measurements ◽  
Habitable Planet ◽  
Airy Disk

Abstract The direct measurement of the universe’s expansion history and the search for terrestrial planets in habitable zones around solar-type stars require extremely high-precision radial-velocity measures over a decade. This study proposes an approach for enabling high-precision radial-velocity measurements from space. The concept presents a combination of a high-dispersion densified pupil spectrograph and a novel line-of-sight monitor for telescopes. The precision of the radial-velocity measurements is determined by combining the spectrophotometric accuracy and the quality of the absorption lines in the recorded spectrum. Therefore, a highly dispersive densified pupil spectrograph proposed to perform stable spectroscopy can be utilized for high-precision radial-velocity measures. A concept involving the telescope’s line-of-sight monitor is developed to minimize the change of the telescope’s line of sight over a decade. This monitor allows the precise measurement of long-term telescope drift without any significant impact on the Airy disk when the densified pupil spectra are recorded. We analytically derive the uncertainty of the radial-velocity measurements, which is caused by the residual offset of the lines of sight at two epochs. We find that the error could be reduced down to approximately 1 cm s−1, and the precision will be limited by another factor (e.g., wavelength calibration uncertainty). A combination of the high-precision spectrophotometry and the high spectral resolving power could open a new path toward the characterization of nearby non-transiting habitable planet candidates orbiting late-type stars. We present two simple and compact highly dispersed densified pupil spectrograph designs for cosmology and exoplanet sciences.

scholarly journals The Design of Large Arc-shape High-precision Walking Device in TV (thermal-vacuum) Conditions

2018 ◽  
Vol 237 ◽  
pp. 03014
Author(s):  
Xue Lian ◽  
Nan Hua ◽  
Liu Jiaqi ◽  
Liu Xin ◽  
Meng Gang
Keyword(s):  
High Precision ◽  
Optical Image ◽  
Thermal Design ◽  
Space Environment ◽  
Test Facility ◽  
Simulation Test ◽  
Thermal Vacuum ◽  
Arc Shape ◽  
Environment Simulation ◽  
Environmental Simulation

The large-sized space environmental simulation test facility is mainly used for providing thermal radiation environment in high-vacuum, cold and dark space for satellites, spacecraft, lunar spacecraft to carry out whole satellite thermal vacuum test and for large equipment like antenna to carry out tests in TV conditions. Monitoring the spacecraft’s surface optical image or temperature is a main task in space environment simulation test. In previous tests, optical image test mainly took place in a fixed position, so the measuring location and angle are limited. This paper focuses on large spherical space environmental simulation test facility, and designs a large arc-shape high-precision walking device in a space environment simulation test device. It introduces key technology in detail like structure design, thermal design, processes and manufacturing, etc. The test results show that this device can work steadily and reliably under simulation space environments, and the precision exceeds 0.5°.

scholarly journals Can we detect Galactic spiral arms? 3D dust distribution in the Milky Way

2017 ◽  
Vol 12 (S330) ◽  
pp. 189-192 ◽  
Author(s):  
Sara Rezaei Kh. ◽  
Coryn A. L. Bailer-Jones ◽  
Morgan Fouesneau ◽  
Richard Hanson
Keyword(s):  
Spatial Correlation ◽  
High Precision ◽  
Milky Way ◽  
Precision Measurements ◽  
Line Of Sight ◽  
Spiral Arms ◽  
Dust Extinction ◽  
The Galaxy ◽  
Galactic Spiral ◽  
Dust Distribution

AbstractWe present a model to map the 3D distribution of dust in the Milky Way. Although dust is just a tiny fraction of what comprises the Galaxy, it plays an important role in various processes. In recent years various maps of dust extinction have been produced, but we still lack a good knowledge of the dust distribution. Our presented approach leverages line-of-sight extinctions towards stars in the Galaxy at measured distances. Since extinction is proportional to the integral of the dust density towards a given star, it is possible to reconstruct the 3D distribution of dust by combining many lines-of-sight in a model accounting for the spatial correlation of the dust. Such a technique can be used to infer the most probable 3D distribution of dust in the Galaxy even in regions which have not been observed. This contribution provides one of the first maps which does not show the “fingers of God” effect. Furthermore, we show that expected high precision measurements of distances and extinctions offer the possibility of mapping the spiral arms in the Galaxy.

scholarly journals High-Precision 3D Reconstruction of Cooperative Markers under Motion Blur

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yun Shi ◽  
Cong Tao ◽  
Xiaoping Wang ◽  
Liyan Zhang
Keyword(s):  
3D Reconstruction ◽  
High Precision ◽  
Exposure Period ◽  
Motion Blur ◽  
Generation Model ◽  
Image Generation ◽  
Reconstruction Accuracy ◽  
Simulation Based ◽  
Blurred Image ◽  
Moving Path

The application of artificial intelligence and deep learning in the fields of wireless communication, image and speech recognition, and 3D reconstruction has successfully solved some difficult modeling problems. This paper focuses on the high-precision 3D reconstruction of the motion-blurred cooperative markers, including the Chinese character coded targets (CCTs) and the noncoded circular markers. A simulation-based motion-blurred image generation model is constructed to provide sufficient samples for training the convolutional neural network to identify and match the motion-blurred CCTs on the moving object. The blurred noncoded marker matching is performed through homography. The 3D reconstruction of the markers is realized via the optimization of the spatial moving path within the exposure period. The midpoint of the moving path of the markers is taken as the final reconstruction result. The experimental results show that the 3D reconstruction accuracy of the markers with a certain motion blur effect is about 0.08 mm.

scholarly journals A Robust PDR/UWB Integrated Indoor Localization Approach for Pedestrians in Harsh Environments

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 193 ◽  
Author(s):  
Haibin Tong ◽  
Ning Xin ◽  
Xianli Su ◽  
Tengfeng Chen ◽  
Jingjing Wu
Keyword(s):  
High Precision ◽  
Indoor Localization ◽  
Poor Performance ◽  
Harsh Environments ◽  
Line Of Sight ◽  
Indoor Environments ◽  
Localization Algorithm ◽  
Advantages And Disadvantages ◽  
Hybrid Localization ◽  
Localization Approach

Wireless sensor networks (WSNs) and the Internet of Things (IoT) have been widely used in industrial, construction, and other fields. In recent years, demands for pedestrian localization have been increasing rapidly. In most cases, these applications work in harsh indoor environments, which have posed many challenges in achieving high-precision localization. Ultra-wide band (UWB)-based localization systems and pedestrian dead reckoning (PDR) algorithms are popular. However, both have their own advantages and disadvantages, and both exhibit a poor performance in harsh environments. UWB-based localization algorithms can be seriously interfered by non-line-of-sight (NLoS) propagation, and PDR algorithms display a cumulative error. For ensuring the accuracy of indoor localization in harsh environments, a hybrid localization approach is proposed in this paper. Firstly, UWB signals cannot penetrate obstacles in most cases, and traditional algorithms for improving the accuracy by NLoS identification and mitigation cannot work in this situation. Therefore, in this study, we focus on integrating a PDR and UWB-based localization algorithm according to the UWB communication status. Secondly, we propose an adaptive PDR algorithm. UWB technology can provide high-precision location results in line-of-sight (LoS) propagation. Based on these, we can train the parameters of the PDR algorithm for every pedestrian, to improve the accuracy. Finally, we implement this hybrid localization approach in a hardware platform and experiment with it in an environment similar to industry or construction. The experimental results show a better accuracy than traditional UWB and PDR approaches in harsh environments.

Synthesis of High-Precision Missile Homing System Using Proportional Guidance Method

2020 ◽  
Vol 21 (4) ◽  
pp. 242-248
Author(s):  
Do Quang Thong
Keyword(s):  
High Precision ◽  
Parametric Optimization ◽  
Initial Conditions ◽  
Dynamic Parameter ◽  
Optimization Method ◽  
Line Of Sight ◽  
Initial Condition ◽  
Optimal Parameters ◽  
Ballistic Missiles ◽  
Low Visibility

Modern air targets are characterized by low visibility, high maneuverability and high survivability. In addition, for some specific targets, for instance ballistic missiles, in order to defeat them the missile need tobe guided and carried out direct hit, i.e. "hit to kill". Therefore, in this paper, we present a high-precision missile homing system (MHS) using the proportional guidance method for firing at the highly maneuverable targets. Specifically, we propose a parametric optimization method for choosing a set of optimal parameters of the missile homing system for each dynamic parameter set of the missile. In addition, the paper gives the recommendations of choosing the initial conditions for the synthesis of missile homing system. In our experience, we should choose the small initial condition for synthesizing the missile homing system. Finally, the article also investigates the influence of systematic error in determining the speed, normal acceleration of missiles and the angular velocity of the line of sight of the missile and target on the accuracy of the missile homing system. We implement the proposed missile homing system and the parametric optimization method in Matlab. The experimental results illustrate that, using proposed system and the parametric optimization method, the missile can defeat the modern air targets with low visibility, high maneuverability and high survivability. 

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