scholarly journals Improvement of Single-pulse Angle Measurement and Tracking Performance Based on Real-time Calibration System for Amplitude and Phase

2016 ◽  
Author(s):  
Zhonghua Zhang ◽  
Huidong Qiao ◽  
Manxi Wang
Keyword(s):  
Real Time ◽  
Single Pulse ◽  
Angle Measurement ◽  
Tracking Performance ◽  
Calibration System ◽  
Time Calibration ◽  
Pulse Angle

Integrated Real-Time Calibration of Electromagnetic Tracking of User Motions for Engineering Applications in Virtual Environments

2002 ◽  
Vol 124 (4) ◽  
pp. 623-632 ◽  
Author(s):  
Uma Jayaram ◽  
Roglenda Repp
Keyword(s):  
Virtual Environments ◽  
Real Time ◽  
Virtual Environment ◽  
Physical World ◽  
Electromagnetic Tracking ◽  
Tracking Systems ◽  
Calibration System ◽  
Time Calibration ◽  
Calibration Accuracy ◽  
Mathematical Techniques

A real-time integrated calibration system for virtual reality environments has been developed that enables accurate electromagnetic tracking of user motions. Electromagnetic tracking systems suffer degradation in accuracy due to the presence of metals and other electromagnetic distortions in the environment. Calibration of the virtual environment to account for these distortions is essential for VR applications in engineering where correlation between the virtual environment and the physical world is important. The major contribution of the paper is the presentation of a comprehensive methodology for calibrating the VR space, the numerical/mathematical techniques proposed for the calibration, and case studies for calibration accuracy and execution time to enable using these techniques in real time in an integrated setup.

scholarly journals Methodology for the Correction of the Spatial Orientation Angles of the Unmanned Aerial Vehicle Using Real Time GNSS, a Shoreline Image and an Electronic Navigational Chart

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2810
Author(s):  
Krzysztof Naus ◽  
Piotr Szymak ◽  
Paweł Piskur ◽  
Maciej Niedziela ◽  
Aleksander Nowak
Keyword(s):  
Real Time ◽  
Spatial Orientation ◽  
Orientation Angle ◽  
Satellite System ◽  
Angle Measurement ◽  
Angle Correction ◽  
Lidar Measurements ◽  
Aerial Vehicle ◽  
Marine Applications ◽  
Global Navigation Satellite

Undoubtedly, Low-Altitude Unmanned Aerial Vehicles (UAVs) are becoming more common in marine applications. Equipped with a Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) receiver for highly accurate positioning, they perform camera and Light Detection and Ranging (LiDAR) measurements. Unfortunately, these measurements may still be subject to large errors-mainly due to the inaccuracy of measurement of the optical axis of the camera or LiDAR sensor. Usually, UAVs use a small and light Inertial Navigation System (INS) with an angle measurement error of up to 0.5∘ (RMSE). The methodology for spatial orientation angle correction presented in the article allows the reduction of this error even to the level of 0.01∘ (RMSE). It can be successfully used in coastal and port waters. To determine the corrections, only the Electronic Navigational Chart (ENC) and an image of the coastline are needed.

Real-time Closed-loop Active Surface Technology of a Large Radio Telescope

2022 ◽  
Vol 134 (1031) ◽  
pp. 015003
Author(s):  
Yong Zhang ◽  
Guoping Li ◽  
Guohua Zhou ◽  
Qishuai Lu ◽  
Heng Zuo ◽  
...  
Keyword(s):  
Real Time ◽  
Radio Telescope ◽  
Closed Loop ◽  
Preliminary Test ◽  
Active Surface ◽  
Angle Measurement ◽  
Quality Data ◽  
Surface Accuracy ◽  
Surface System ◽  
Reflector Surface

Abstract The surface accuracy of a large radio telescope’s primary reflector is easily affected by gravity and temperature change during observations. An active surface system is crucial to ensure the regular operation and high-quality data output of the radio telescope. We propose a real-time closed-loop active surface system including two components. The first component, a new type of photoelectric edge sensor, detects the angle change of the adjacent panels. The second component, the displacement actuator, adjusts the panels’ position and posture to compensate for the angle changes. So, over the entire observation, the closed-loop surface control system with these two components could actively maintain the primary reflector’s accuracy in real time. Using this approach, we constructed an experimental active surface system for the Xinjiang Qitai 110 m Radio Telescope (QTT) to test the maintenance of the surface accuracy. The angle measurement accuracy is better than 0.″2, and the positioning accuracy of the displacement actuator could achieve ±15 μm over the whole 50 mm stroke. The preliminary test results show that the accuracy requirements of the QTT’s primary reflector surface can be met using the active surface system we propose.

Multiple Ship Motion Simulation Code Correlation with Model Test Results

2017 ◽  
Author(s):  
James A. Coller ◽  
Andrew Silver ◽  
Okey Nwogu ◽  
Benjamin S.H. Connell
Keyword(s):  
Real Time ◽  
Model Test ◽  
Three Dimensional ◽  
Angle Measurement ◽  
Ship Motion ◽  
Ship Motions ◽  
Simulation Code ◽  
Forecasting System ◽  
Scale Experiment ◽  
Response Amplitude Operators

The US Nav has developed a real-time multi-ship ship motion forecasting system which combines forecast wave conditions with ship motion simulations to produce a prediction of the relative motions between two ships operating in a skin-to-skin configuration. The system utilizes two different simulation methods for predicting ship motions: MotionSim and Reduced Order Model (ROM) based on AEGIR. MotionSim is a fast three-dimensional panel method that is used to estimate the Response Amplitude Operators (RAOs) necessary for multi-ship motion predictions. The ROM works to maximize the accuracy of high fidelity ship motion prediction methods while maintaining the computational speed required for real-time forecasting. A model scale experiment was performed in 2015 on two Navy ships conventionally moored together. The predicted relative ship motions from MotionSim and ROM were compared to the model data using three different metrics: RMS (root mean square) ratio, correlation coefficient, and average angle measurement (AAM).This paper provides an overview of the two methods for predicting the multi-ship motions, a description of the model test, challenges faced during testing, and a discussion on the methodology of the evaluation and the results of each code correlation.

scholarly journals Radiometer for Real-time Calibration of the Xenon Arc Lamps

2018 ◽  
Vol 1065 ◽  
pp. 032010
Author(s):  
D J Yin ◽  
F S Lin ◽  
T C Li ◽  
W H Cheng ◽  
M Y Ji ◽  
...  
Keyword(s):  
Real Time ◽  
Time Calibration

High-Accuracy Real Time Calibration of Tunable Fabry-Pérot Filter on Large Range

2008 ◽  
Vol 28 (5) ◽  
pp. 852-855
Author(s):  
乔学光 Qiao Xueguang ◽  
王瑜 Wang Yu ◽  
傅海威 Fu Haiwei ◽  
赵大壮 Zhao Dazhuang ◽  
王炜 Wang Wei ◽  
...  
Keyword(s):  
Real Time ◽  
Large Range ◽  
High Accuracy ◽  
Time Calibration ◽  
Fabry Perot

Method of Real-Time Calibration for Tunable Optical Filter Nonlinearity

2010 ◽  
Vol 37 (6) ◽  
pp. 1445-1449 ◽  
Author(s):  
梁霄 Liang Xiao ◽  
刘铁根 Liu Tiegen ◽  
刘琨 Liu Kun ◽  
江俊峰 Jiang Junfeng ◽  
张以谟 Zhang Yimo
Keyword(s):  
Real Time ◽  
Optical Filter ◽  
Tunable Optical Filter ◽  
Time Calibration
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