scholarly journals Absolute Quadrant Determinations from Speckle Observations of Binary Stars

1992 ◽  
Vol 135 ◽  
pp. 536-536
Author(s):  
W.G. Bagnuolo ◽  
B.D. Mason ◽  
D.J. Barry ◽  
W.I. Hartkopf ◽  
H.A. McAlister
Keyword(s):  
Power Spectrum ◽  
Real Time ◽  
Binary Stars ◽  
Position Angle ◽  
Angle Measurement

AbstractReduction of speckle data obtained for binary stars is typically carried out using power spectrum or, equivalently, autocorrelation methods. An especially powerful algorithm from which accuate differential astronomy can be obtained is the vector autocorrelation technique. While such methods are highly suited to extracting astrometric information from very large volumes of speckle data in near real–time, they inherently introduce a 180° ambiguity in position angle measurement. We briefly summarize results with a new algorithm which maintains most of the simplicity of vector autocorrelation while removing the quadrant ambiguity.

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 Real Time Load Angle Application for Synchronous Generator Protection Purposes

2020 ◽  
Vol 69 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Ivan Višić ◽  
Ivan Strnad ◽  
Tihomir Tonković
Keyword(s):  
Real Time ◽  
Synchronous Generator ◽  
Angle Measurement ◽  
New Approach ◽  
The Real ◽  
Generator Protection ◽  
Step Generator ◽  
Load Angle

The out-of-step protection function is one of the key functions in generator protection. This function detects the loss of generator synchronism, and when such a fault occurs, it is necessary to disconnect the generator from the rest of the system as soon as possible in order to avoid major damages.The algorithms used in the out-of-step protection functions are based on the measurements of generator impedances and they use the impedance vectors to check if all stability criterions are met. This paper describes a new approach to realizing the out-of-step generator protection function by using the direct load angle measurement. The idea behind applying the real time load angle measurement is to faster detect the loss of synchronism.

scholarly journals Synchronous Generator Out of Step Detection Using Real Time Load Angle Data

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3336
Author(s):  
Ivan Višić ◽  
Ivan Strnad ◽  
Ante Marušić
Keyword(s):  
Power System ◽  
Real Time ◽  
Synchronous Generator ◽  
Angle Measurement ◽  
Impedance Change ◽  
Generator Protection ◽  
Angle Measurements ◽  
Angle Data ◽  
Key Issues ◽  
Load Angle

Although the power system usually always appears stable and reliable to consumers, a lot of work and research goes into keeping the power system both stable and reliable under constantly changing conditions and in these increasingly demanding times. One of the key issues in the power system is maintaining stability after large disturbances in order to prevent the loss of synchronicity of the generators in the system. Today’s generator protection systems mostly use measurements of impedance change to detect generator out of step. This article discusses the possibility of detecting the loss of synchronicity by using real time load angle measurements. The authors propose a real time load angle measurement algorithm and present the results of the algorithm’s testing performed on a real hydrogenerator. The results show that the developed algorithm gives highly accurate real time load angle measurements with the maximum possible resolution and that the load angle can be used for detecting the synchronous generator out of step.

scholarly journals Research on the Peripheral Sound Visualization Using the Improved Ripple Mode

2011 ◽  
Vol 2-3 ◽  
pp. 123-126
Author(s):  
Bin Xu ◽  
Dan Yang ◽  
Yun Yi Zhang ◽  
Xu Wang
Keyword(s):  
Neural Network ◽  
Power Spectrum ◽  
Real Time ◽  
Sound Source ◽  
Sound Intensity ◽  
Visualization Method ◽  
Audio Signals ◽  
Sound Sources ◽  
The Real ◽  
Spectrum Function

In this paper, we proposed a peripheral sound visualization method based on improved ripple mode for the deaf. In proposed mode, we designed the processes of transforming sound intensity and exterminating the locations of sound sources. We used power spectrum function to determine the sound intensity. ARTI neural network was subtly applied to identify which kind of the real-time input sound signals and to display the locations of the sound sources. We present the software that aids the development of peripheral displays and four sample peripheral displays are used to demonstrate our toolkit’s capabilities. The results show that the proposed ripple mode correctly showed the information of combination of the sound intensity and location of the sound source and ART1 neural network made accurate identifications for input audio signals. Moreover, we found that participants in the research were more likely to achieve more information of locations of sound sources.

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