scholarly journals A Novel Estimation Method of Wind Speed and Direction Based on GNSS/INS/ADS Integrated Navigation

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jingjuan Zhang ◽  
Hao Cong ◽  
Xueyun Wang
Keyword(s):  
Wind Speed ◽  
Direct Measurement ◽  
Navigation System ◽  
Measurement Method ◽  
Dynamic Models ◽  
Unscented Kalman Filter ◽  
Estimation Method ◽  
Accurate Information ◽  
Wind Condition ◽  
Direct Measurement Method

Arriving on time is of great importance for flight management and passenger experience. One of the essential factors that impacts on-time arrival is the wind condition. Accurate information of wind speed and direction around the fuselage helps to improve the performance of on-time arrival and four-dimensional trajectory (4DT) planning. To determine accurate wind information in real-time, a novel airborne estimation method of wind speed and direction is proposed in this paper. Inertial Navigation System (INS), Global Satellite Navigation System (GNSS), and Air Data System (ADS) are fused in an Unscented Kalman Filter (UKF), which provides great accuracy and robustness in nonlinearity conditions. The dynamic models of wind are established, and implementations of the UKF are detailed. Finally, simulations are designed and the effectiveness of the proposed method is verified through the comparison with the traditional direct measurement method. Results demonstrate that the accuracy of wind speed and direction obtained by our method is nearly two times higher than the traditional direct measurement method.

scholarly journals JOM-4S Overhauser Magnetometer and Sensitivity Estimation

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7698
Author(s):  
Xiaorong Gong ◽  
Shudong Chen ◽  
Shuang Zhang
Keyword(s):  
Magnetic Field ◽  
Direct Measurement ◽  
Measurement Method ◽  
Technical Specification ◽  
Estimation Method ◽  
Earth’S Magnetic Field ◽  
Sensitivity Estimation ◽  
Earth's Magnetic Field ◽  
Direct Measurement Method ◽  
Synchronous Measurement

The Overhauser magnetometer is a scalar quantum magnetometer based on the dynamic nuclear polarization (DNP) effect in the Earth’s magnetic field. Sensitivity is a key technical specification reflecting the ability of instruments to sense small variations of the Earth’s magnetic field and is closely related to the signal-to-noise ratio (SNR) of the free induction decay (FID) signal. In this study, deuterated 15N TEMPONE radical is used in our sensor to obtain high DNP enhancement. The measured SNR of the FID signal is approximately 63/1, and the transverse relaxation time T2 is 2.68 s. The direct measurement method with a single instrument and the synchronous measurement method with two instruments are discussed for sensitivity estimation in time and frequency domains under different electromagnetic interference (EMI) environments and different time periods. For the first time, the correlation coefficient of the magnetic field measured by the two instruments is used to judge the degree of the influence of the environmental noise on the sensitivity estimation. The sensitivity evaluation in the field environment is successfully realized without electrical and magnetic shields. The direct measurement method is susceptible to EMI and cannot work in general electromagnetic environments, except it is sufficiently quiet. The synchronous measurement method has an excellent ability to remove most natural and artificial EMIs and can be used under noisy environments. Direct and synchronous experimental results show that the estimated sensitivity of the JOM-4S magnetometer is approximately 0.01 nT in time domain and approximately 0.01 nT/ in frequency domain at a 3 s cycling time. This study provides a low-cost, simple, and effective sensitivity estimation method, which is especially suitable for developers and users to estimate the performance of the instrument.

A New Direct Measurement Method of Time Dependent Dielectric Breakdown at High Frequency

2020 ◽  
Vol 41 (10) ◽  
pp. 1460-1463
Author(s):  
Melissa Arabi ◽  
Xavier Garros ◽  
Jacques Cluzel ◽  
Mustapha Rafik ◽  
Xavier Federspiel ◽  
...  
Keyword(s):  
Direct Measurement ◽  
High Frequency ◽  
Measurement Method ◽  
Dielectric Breakdown ◽  
Time Dependent ◽  
Time Dependent Dielectric Breakdown ◽  
Direct Measurement Method

A Direct Measurement Method of Yarn Evenness Based on Machine Vision

2015 ◽  
Vol 10 (4) ◽  
pp. 155892501501000 ◽  
Author(s):  
Junjuan Li ◽  
Baoqi Zuo ◽  
Chen Wang ◽  
Wenxiao Tu
Keyword(s):  
Machine Vision ◽  
Direct Measurement ◽  
Coefficient Of Variation ◽  
Measurement Method ◽  
Main Body ◽  
Quality Grade ◽  
Yarn Count ◽  
Image Acquisition System ◽  
Direct Measurement Method ◽  
Morphological Opening

In this paper, a new yarn evenness measurement method based on machine vision is introduced, which is a direct measurement process, as opposed to other methods. Two types of yarns (i.e., same yarn count but different quality grade and same quality grade but different yarn count) are measured to determine the coefficient of variation unevenness, which can be compared with the results of USTER ME100. The yarn images are continuously captured via an image acquisition system. To determine the main body of the yarn accurately, the yarn images are processed sequentially by a threshold segmentation and morphological opening operation. Next, the coefficient of variation (CV value) of the diameter is calculated to characterize the yarn evenness. Different image processing methods are used and compared to obtain a suitable method for use in the experiment. A more accurate, more efficient, and faster measurement system will meet requirements of the manufacturing of yarn; the suitable performance of the proposed method is illustrated using experimental results.

A Direct Measurement Method of Building’s Shunt Coefficient

2012 ◽  
Vol 241-244 ◽  
pp. 885-888
Author(s):  
Xiao Chun Zhang ◽  
Xiu Bin Sun ◽  
Xiang Yong Mou
Keyword(s):  
Direct Measurement ◽  
Measurement Method ◽  
Pulse Current ◽  
Induction Coil ◽  
Experimental Results ◽  
Current Generator ◽  
Digital Oscilloscope ◽  
Direct Measurement Method

The shunt coefficient of a model of constructions was measured by a pulse current generator, an induction coil, a digital oscilloscope. The experimental results demonstrate that the method is effective, the distribution of pulse current in a buildings can be directly measured without damage.

Identification in Rotordynamics: Model-Based vs. Direct Measurements

2009 ◽  
Author(s):  
Qingyu Wang ◽  
Brian Pettinato ◽  
Eric Maslen
Keyword(s):  
Analytical Model ◽  
Direct Measurement ◽  
Dynamic Characteristics ◽  
Measurement Method ◽  
Transfer Functions ◽  
Subsequent Paper ◽  
Quality Estimation ◽  
Model Based ◽  
Equation Solving ◽  
Direct Measurement Method

In a rotor-bearing system, there are usually some under- or unmodeled components, such as foundations and seals. Identifying the dynamic characteristics of these components often requires both an analytical model and test data due to the working conditions, such as running speed above the first bending mode and non-collocation measurements. The existing methods always identify the dynamic characteristics by solving the equations of motion at discrete frequencies of the measured frequency response functions (FRFs). They have two problems: first, the physical background of the identification is buried in the equation solving process, and second, there is no quality estimation of the identified result. This paper discusses the first problem which is the equation solving process. The second problem, quality estimation, is discussed in a subsequent paper [1]. This paper reveals that model-based identification is the interconnection of certain transfer functions. These transfer functions are either generated from an analytical model (the common model-based method), or directly measured (direct measurement method). The process of both these methods is then illustrated by use of experimental data. A novel seal test design is proposed based on the idea of the direct measurement method. Identification under complex situations is also considered as complementary to the main content, such as different input/output locations. The conditions for identifiability are given.

scholarly journals Effect of Starting Cadence on Sprint-Performance Indices in Friction-Loaded Cycle Ergometry

2007 ◽  
Vol 2 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Rachel L. Wright ◽  
Dan M. Wood ◽  
David V.B. James
Keyword(s):  
Direct Measurement ◽  
Peak Power ◽  
Measurement Method ◽  
Cycle Ergometry ◽  
Sprint Performance ◽  
Performance Indices ◽  
Men And Women ◽  
Time To Peak ◽  
Main Effect ◽  
Direct Measurement Method

The aims of the study were to investigate whether starting cadence had an effect on 10-s sprint-performance indices in friction-loaded cycle ergometry and to investigate the influence of method of power determination. In a counterbalanced order, 12 men and 12 women performed three 10-s sprints using a stationary (0 rev/min), moderate (60 rev/min), and high (120 rev/min) starting cadence Calculated performance indices were peak power, cadence at peak power, time to peak power, and work to peak power. When the uncorrected method of power determination was applied, there was a main effect for starting cadence in female participants for peak power (stationary 635 ± 183.7 W, moderate 615.4 ± 168.9 W and high 798.4 ± 120.1 W) and cadence at peak power (89.8 ± 2.3 rev/min, 87.9 ± 21.5 rev/min, and 113.1 ± 12.5 rev/min). For both the uncorrected and directly measured methods of power determination in men and women, there was a main effect for starting cadence for time to peak power and work to peak power. In women, for an uncorrected method of power determination, it can be concluded that starting cadence does affect peak power and cadence at peak power. This effect is, however, negated by a direct-measurement method of power determination. In men and women, for both uncorrected and directly measured methods o power determination, time to peak power and work to peak power were affected by starting cadence. Therefore, a higher-cadence start is unsuitable, particularly when sprint-performance indices are determined from an uncorrected method.

Director field in a liquid crystal: direct measurement method

1998 ◽  
Author(s):  
Andrzej Walczak ◽  
Edward Nowinowski-Kruszelnicki ◽  
Aleksander Kiezun
Keyword(s):  
Liquid Crystal ◽  
Direct Measurement ◽  
Measurement Method ◽  
Director Field ◽  
Direct Measurement Method

scholarly journals Optical Wavelength Meter Calibration Using Iodine Stabilized He-Ne Laser by Direct Measurement Method

2017 ◽  
Vol 170 ◽  
pp. 363-368 ◽  
Author(s):  
Adhika Widya Sena ◽  
Asep Hapiddin ◽  
Ratnaningsih ◽  
Mohamad Syahadi ◽  
Endang Juliastuti
Keyword(s):  
Direct Measurement ◽  
Measurement Method ◽  
Optical Wavelength ◽  
Direct Measurement Method

scholarly journals Measurement method for incisions ablated by femtosecond laser in biological soft tissues

2021 ◽  
Author(s):  
Xiaowei Shen ◽  
Zhao wanqin ◽  
Haodong Liu ◽  
Ning Wang ◽  
Xu Wang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Direct Measurement ◽  
Measurement Method ◽  
Soft Tissues ◽  
Optical Microscope ◽  
Indirect Measurement ◽  
Chicken Breast ◽  
High Measurement ◽  
Direct Measurement Method ◽  
Measurement Efficiency

Abstract BackgroundHematoxylin and Eosin staining in paraffin embedded tissue (H&E staining in paraffin embedded tissue) is a widely used method in the incision dimensions measurement. Since H&E staining in paraffin embedded tissue requires complicated process and spends a lot of time, a direct measurement method based on a microscope is proposed to measure the incision dimensions, which greatly improves the efficiency.AimIn this paper, a direct measurement method using optical microscope and an indirect measurement method based on H&E staining in paraffin embedded tissue are presented and compared, so as to obtain a better method of measurement efficiency and accuracy.ApproachThe femtosecond laser is used to process chicken breast tissue, the directly measurement method based on a microscope and indirectly measurement method based on H&E staining are used to measure dimensions. Moreover, the laser confocal microscopy measurement (LCM) is also used to measure the incision depth.ResultsIt was found that the direct measurement method has high measurement efficiency and accuracy for incision dimensions measurement.ConclusionsOverall, the incision dimensions obtained by femtosecond laser processing can be measured through the direct measurement method instead of H&E staining in paraffin embedded tissue.

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