scholarly journals Study on Misalignment Angle Compensation during Scale Factor Matching for Two Pairs of Accelerometers in a Gravity Gradient Instrument

Sensors ◽  
2018 ◽  
Vol 18 (4) ◽  
pp. 1247 ◽  
Author(s):  
Xiangqing Huang ◽  
Zhongguang Deng ◽  
Yafei Xie ◽  
Ji Fan ◽  
Chenyuan Hu ◽  
...  
Keyword(s):  
Scale Factor ◽  
Gravity Gradient ◽  
Misalignment Angle ◽  
Factor Matching

scholarly journals Scale Factor Calibration for a Rotating Accelerometer Gravity Gradiometer

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4386
Author(s):  
Zhongguang Deng ◽  
Chenyuan Hu ◽  
Xiangqing Huang ◽  
Wenjie Wu ◽  
Fangjing Hu ◽  
...  
Keyword(s):  
Field Tests ◽  
Scale Factor ◽  
Gravity Gradient ◽  
Gravity Gradiometer ◽  
Calibration System ◽  
Theoretical Simulation ◽  
Error Analyses ◽  
Good Consistency ◽  
Resource Exploration ◽  
Simulation Error

Rotating Accelerometer Gravity Gradiometers (RAGGs) play a significant role in applications such as resource exploration and gravity aided navigation. Scale factor calibration is an essential procedure for RAGG instruments before being used. In this paper, we propose a calibration system for a gravity gradiometer to obtain the scale factor effectively, even when there are mass disturbance surroundings. In this system, four metal spring-based accelerometers with a good consistency are orthogonally assembled onto a rotary table to measure the spatial variation of the gravity gradient. By changing the approaching pattern of the reference gravity gradient excitation object, the calibration results are generated. Experimental results show that the proposed method can efficiently and repetitively detect a gravity gradient excitation mass weighing 260 kg within a range of 1.6 m and the scale factor of RAGG can be obtained as (5.4 ± 0.2) E/μV, which is consistent with the theoretical simulation. Error analyses reveal that the performance of the proposed calibration scheme is mainly limited by positioning error of the excitation and can be improved by applying higher accuracy position rails. Furthermore, the RAGG is expected to perform more efficiently and reliably in field tests in the future.

scholarly journals A Calibration Method for the Errors of Ring Laser Gyro in Rate-Biased Mode

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4754
Author(s):  
Zengjun Liu ◽  
Lei Wang ◽  
Kui Li ◽  
Jingxuan Ban ◽  
Meng Wang
Keyword(s):  
Ring Laser ◽  
Inertial Measurement Unit ◽  
Inertial Navigation System ◽  
Calibration Method ◽  
Scale Factor ◽  
Measurement Unit ◽  
Misalignment Angle ◽  
Laser Gyro ◽  
Constant Bias ◽  
The Difference

Ring laser gyro (RLG) can work in mechanically dithered mode or rate-biased mode according to the working state of the inertial navigation system (INS). It can change from one mode to the other by receiving outer instructions. To evaluate the performance of RLG in rate-biased mode, an inertial measurement unit (IMU) based on RLG is installed on a dual-axis turntable, the turntable offers a constant angular velocity to the RLGs, in that way RLG can work in the rate-biased mode. A calibration method is proposed to calibrate the scale factor error, misalignments and constant bias of RLG in rate-biased mode, experiment results show that the differences of scale factor of the three gyros in two modes are 9 ppm, 7 ppm and 3.5 ppm, the constant biases of the three RLGs in rate-biased mode are also different from that in mechanically dithered mode with the difference of 0.017°/h, 0.011°/h and 0.020°/h, the input axis misalignment angle of RLGs in different modes also changed. What is more, a calculation method of angle random walk (ARW) of RLG in rate-biased mode is also presented. Experimental results show that the ARW of the RLG in rate-biased mode is about one third of that in mechanically dithered.

The Basic Empathy Scale: Factor structure and validity in a sample of inpatient adolescents.

2019 ◽  
Vol 31 (10) ◽  
pp. 1208-1219 ◽  
Author(s):  
Veronica McLaren ◽  
Salome Vanwoerden ◽  
Carla Sharp
Keyword(s):  
Factor Structure ◽  
Scale Factor ◽  
Empathy Scale ◽  
Basic Empathy Scale

Ultra Short Baseline (USBL) Calibration for Positioning of Underwater Objects

2019 ◽  
Vol 2 (2) ◽  
pp. 73-85
Author(s):  
Bagus Septyanto ◽  
Dian Nurdiana ◽  
Sitti Ahmiatri Saptari
Keyword(s):  
Acoustic Wave ◽  
Scale Factor ◽  
Positioning System ◽  
Radio Waves ◽  
Short Baseline ◽  
Error Angle ◽  
Satellite Navigation System ◽  
The Earth ◽  
Underwater Positioning ◽  
Radio Signals

In general, surface positioning using a global satellite navigation system (GNSS). Many satellites transmit radio signals to the surface of the earth and it was detected by receiver sensors into a function of position and time. Radio waves really bad when spreading in water. So, the underwater positioning uses acoustic wave. One type of underwater positioning is USBL. USBL is a positioning system based on measuring the distance and angle. Based on distance and angle, the position of the target in cartesian coordinates can be calculated. In practice, the effect of ship movement is one of the factors that determine the accuracy of the USBL system. Ship movements like a pitch, roll, and orientation that are not defined by the receiver could changes the position of the target in X, Y and Z coordinates. USBL calibration is performed to detect an error angle. USBL calibration is done by two methods. In USBL calibration Single Position obtained orientation correction value is 1.13 ̊ and a scale factor is 0.99025. For USBL Quadrant calibration, pitch correction values is -1.05, Roll -0.02 ̊, Orientation 6.82 ̊ and scale factor 0.9934 are obtained. The quadrant calibration results deccrease the level of error position to 0.276 - 0.289m at a depth of 89m and 0.432m - 0.644m at a depth of 76m

Development of Quality Early Childhood Care and Education (QECCE) Scale: Factor Structural and Psychometric Properties

2019 ◽  
Vol 18 (11) ◽  
pp. 385-396
Author(s):  
Wong Kung-Teck ◽  
Jamilah Omar ◽  
Sopia Md Yassin ◽  
Mazlina Che Mustafa ◽  
Norazilawati Abdullah ◽  
...  
Keyword(s):  
Early Childhood ◽  
Psychometric Properties ◽  
Scale Factor ◽  
Early Childhood Care ◽  
Childhood Care

Progressive Early Rehabilitation Program Applied to Patients with Acute Cerebrovascular Accident

2020 ◽  
Vol 25 (3) ◽  
pp. 17-25 ◽  
Author(s):  
G. R. Ramazanov ◽  
L. B. Zavaliy ◽  
L. L. Semenov ◽  
S. A. Abudeev ◽  
A. O. Ptitsyn ◽  
...  
Keyword(s):  
Cerebrovascular Accident ◽  
Lung Ventilation ◽  
Rehabilitation Program ◽  
Artificial Lung ◽  
Early Rehabilitation ◽  
Gravity Gradient ◽  
Acute Cerebrovascular Accident ◽  
Artificial Lung Ventilation ◽  
Bed Days ◽  
Severity Of The Disease

Abstract. Early rehabilitation (ER) of patients with acute cerebrovascular accident (ACA) is one of the priority tasks of the vascular centers; the issue of increasing the volume of rehabilitation measures in the resuscitation and intensive care units (ICU) is relevant. Objective. To evaluate the safety and effectiveness of the progressive ER program in patients with ACA. Material and research methods. The study included 129 patients with ACA in ICU. Each patient of the main group (MGr, n = 61) underwent progressive ER: at least 4–5 vertical adjustments per day, passive mode Kinesiotherapy 49 ± 9.3 minutes, a double load of physiotherapy exercises, preventive physiotherapy; the total time of classes reached 240 minutes per day. In the comparison group (СGr, n = 68), standard ER was performed no more than 120 minutes per day. The groups are comparable by sex, age, severity of the disease and comorbidity. The severity of ACA, the gravity gradient, patient mobility, functional status, degree of dependence, and the presence of complications were evaluated. Results. During a month of work with the MGr, 102 ICU bed-days, 94 days of the artificial lung ventilation use, p < 0.05 were saved. Mortality in MGr decreased -— 8 patients (13.1%) versus 14 (20.6%) in CGr (p < 0.05). In patients within CGr, pulmonary thromboembolism developed in 8.8%, in MGr – in 3.3%. The severity of the apoplectic attack decreased ( by 28% in MGr, and by 20% in CGr ), mobility increased. Comparing the modalities of post resuscitationsyndrome in MGr, it was noted that the score decreased by 2 times from 6 [5; 6] to 3 [2.3; 3.3], but it has not changed in the CGr. Patients in the MGr were 2-–3 days earlier adapted to the vertical adjustment. Conclusions. The progressive ER program in ICU is safe, effective, realisable, and allows reducing the number of bed-days in ICU, the number of days of the artificial lung ventilation use, complications, and mortality in comparison with standard medical care.

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