Attitude Angle Measurement Method Based on the Three-Dimensional Accelerometer

2013 ◽  
Vol 333-335 ◽  
pp. 152-156
Author(s):  
Yu Fa Tang ◽  
He Zhang ◽  
Li Hong
Keyword(s):  
Circuit Design ◽  
Inclination Angle ◽  
Attitude Determination ◽  
Three Dimensional ◽  
Angle Measurement ◽  
Two Dimensional ◽  
Theoretical Support ◽  
Attitude Angle ◽  
Hardware Circuit

On the basis of a study of measuring inclination angle with a two-dimensional accelerometer, a principle method using a three-dimensional accelerometer to measure attitude angle is analysed on the condition of micro-rotating. The method can reduce random systematic errors caused by uniaxial or biaxial output of the two-dimensional accelerometer. It can simultaneously measure both inclination angle and roll angle. So hardware selection, hardware circuit design and experiments are done: simulate the roll and tilt movement of the special objects and compare the solver results with the actual results. The principle method achieves preferable results, and provides a theoretical support for attitude determination of a particular industry as well.

Multivariate Constrained GNSS Real-time Full Attitude Determination Based on Attitude Domain Search

2018 ◽  
Vol 72 (2) ◽  
pp. 483-502
Author(s):  
Hongtao Wu ◽  
Xiubin Zhao ◽  
Chunlei Pang ◽  
Liang Zhang ◽  
Bo Feng
Keyword(s):  
Objective Function ◽  
Success Rate ◽  
High Efficiency ◽  
Attitude Determination ◽  
A Priori ◽  
Three Dimensional ◽  
Satellite System ◽  
New Method ◽  
Lambda Method ◽  
Attitude Angle

A priori attitude information can improve the success rate and reliability of Global Navigation Satellite System (GNSS) multi-antennae attitude determination. However, a priori attitude information is nonlinear, and integrating a priori information into the objective function rigorously will increase the complexity of an ambiguity domain search, such as the Multivariate Constrained-Least-squares Ambiguity Decorrelation Adjustment (MC-LAMBDA) method. In this paper, a new method based on attitude domain search is presented to make use of the a priori attitude angle information with high efficiency. First, the a priori information of pitch and roll is integrated into the search process to derive the analytic search step for attitude angle, and the integer candidates are determined by traversal search in the three-dimensional attitude domain. Then, the objective function is parameterised with Euler angles, and a non-iterative approximate method is utilised to simplify the iterative computation in calculating objective function values. Experimental results reveal that compared to the MC-LAMBDA method, our new method has the same success rate and reliability, but higher efficiency in making use of a priori attitude information.

Expanding the theory: Nonverbal determination of referents in a joystick task

2001 ◽  
Vol 24 (2) ◽  
pp. 224-225
Author(s):  
Katherine A. Leighty ◽  
Sarah E. Cummins-Sebree ◽  
Dorothy M. Fragaszy
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Nonhuman Species

The arguments of Stoffregen & Bardy for studying perception based on the global array are intriguing. This theory can be examined in nonhuman species using nonverbal tasks. We examine how monkeys master a skill that incorporates a two-dimensional/three-dimensional interface. We feel this provides excellent support for Stoffregen & Bardy's theory.

The method of caustics for the determination of normal loads acting on surfaces of elastic bodies

1980 ◽  
Vol 15 (1) ◽  
pp. 37-41 ◽  
Author(s):  
P S Theocaris ◽  
N I Ioakimidis
Keyword(s):  
Three Dimensional ◽  
Contact Problems ◽  
Two Dimensional ◽  
Concentrated Force ◽  
Elastic Bodies ◽  
Plate And Shell ◽  
Elasticity Problems ◽  
Three Dimensional Elasticity ◽  
Quantities Of Interest

The optical method of caustics constitutes an efficient experimental technique for the determination of quantities of interest in elasticity problems. Up to now, this method has been applied only to two-dimensional elasticity problems (including plate and shell problems). In this paper, the method of caustics is extended to the case of three-dimensional elasticity problems. The particular problems of a concentrated force and a uniformly distributed loading acting normally on a half-space (on a circular region) are treated in detail. Experimentally obtained caustics for the first of these problems were seen to be in satisfactory agreement with the corresponding theoretical forms. The treatment of various, more complicated, three-dimensional elasticity problems, including contact problems, by the method of caustics is also possible.

Electron Crystallographic Determination of the Structure of Bacteriorhodopsin

1990 ◽  
Vol 48 (1) ◽  
pp. 90-91
Author(s):  
R. Henderson ◽  
J.M. Baldwin ◽  
T.A. Ceska ◽  
E. Beckman ◽  
F. Zemlin ◽  
...  
Keyword(s):  
High Resolution ◽  
Proton Pump ◽  
Three Dimensional ◽  
Atomic Resolution ◽  
Two Dimensional ◽  
New Methods ◽  
Density Map ◽  
Diffraction Patterns

The light driven proton pump bacteriorhodopsin (bR) occurs naturally as two-dimensional crystals. A three-dimensional density map of the structure, at near atomic resolution, has been obtained by studying the crystals using electron cryo-microscopy to obtain diffraction patterns and high resolution micrographs (1).New methods have been developed for analysing micrographs from tilted specimens, incorporating the methods previously developed for untilted specimens that enable large areas to be analysed and corrected for distortions. Data from 72 images, from both tilted and untilted specimens, have been analysed to produce the phases of 2700 independent Fourier components of the structure. The amplitudes of these components have been accurately measured from 150 diffraction patterns. Together, these data represent about half of the full three-dimensional transform to 3.5 Å. The distribution of the data which is included in the map is shown in fig. 1. For specimen tilts up to around 20° the data is essentially complete. For higher tilts the data is more sparsely sampled, and is at present about half complete.

Polypeptide chain configurations in crystalline proteins

1950 ◽  
Vol 203 (1074) ◽  
pp. 321-357 ◽  
Keyword(s):  
General Type ◽  
Polypeptide Chain ◽  
Three Dimensional ◽  
Chain Structure ◽  
Two Dimensional ◽  
Amino Acid Residues ◽  
Intensive Study ◽  
Repeat Distance ◽  
X Ray

Astbury’s studies of α-keratin, and X-ray studies of crystalline haemoglobin and myoglobin by Perutz and Kendrew, agree in indicating some form of folded polypeptide chain which has a repeat distance of about 5·1 Å, with three amino-acid residues per repeat. In this paper a systematic survey has been made of chain models which conform to established bond lengths and angles, and which are held in a folded form by N—H—O bonds. After excluding the models which depart widely from the observed repeat distance and number of residues per repeat, an attempt is made to reduce the number of possibilities still further by comparing vector diagrams of the models with Patterson projections based on the X-ray data. When this comparison is made for two-dimensional Patterson projections on a plane at right angles to the chain, the evidence favours chains of the general type proposed for a-keratin by Astbury. These chains have a dyad axis with six residues in a repeat distance of 10·2 Å, and are composed of approximately coplanar folds. As a further test, these chains are placed in the myoglobin structure, and a comparison is made between calculated and observed F values for a zone parallel to the chains; the agreement is remarkably close taking into account the omission from the calculations of the unknown effect of the side-chains. On the other hand, a study of the three-dimensional Patterson of haemoglobin shows how cautious one must be in accepting this agreement as significant. Successive portions of the rod of high vector density which has been supposed to represent the chains give widely different projections and show no evidence of a dyad axis. The evidence is still too slender for definite conclusions to be drawn, but it indicates that a further intensive study of these proteins, and in particular of myoglobin which has promising features of simplicity, may lead to a determination of the chain structure.

COMPUTER MIGRATION OF OBLIQUE SEISMIC REFLECTION PROFILES

Geophysics ◽  
1975 ◽  
Vol 40 (6) ◽  
pp. 961-980 ◽  
Author(s):  
William S. French
Keyword(s):  
Seismic Reflection ◽  
Three Dimensional ◽  
Migration Velocity ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Reflection Data ◽  
Line Imaging ◽  
Geometrical Factors ◽  
Seismic Reflection Profiles

A reflecting interface with irregular shape is overlain by a material of constant velocity [Formula: see text]. Multifold reflection data are collected on a plane above the reflector and the reflector is imaged by first stacking then migrating the reflection data. There are three velocity functions encountered in this process: the measured stacking velocity [Formula: see text]; the true overburden velocity [Formula: see text]; and a profile migration velocity [Formula: see text], which is required by present point‐imaging migration programs. Methods of determining [Formula: see text] and, subsequently, [Formula: see text] are well‐known. The determination of [Formula: see text] from [Formula: see text], on the other hand, has not been previously discussed. By considering a line‐imaging migration process we find that [Formula: see text] depends not only on the true section velocity but also on certain geometrical factors which relate the profile direction to the structure. The relation between [Formula: see text] and [Formula: see text] is similar to, but should not be confused with, the known relation between [Formula: see text] and [Formula: see text]. The correct profile migration velocity is always equal to or greater than the true overburden velocity but may be less than, equal to, or greater than the best stacking velocity. When a profile is taken at an angle of (90−θ) degrees to the trend of a two‐dimensional structure, then the appropriate migration velocity is [Formula: see text] and is independent of the magnitude of any dips present. If, in addition, the two‐dimensional structure plunges along the trend at an angle γ, then the correct migration velocity is given by [Formula: see text]. The time axis of the migrated profile for the plunging two‐dimensional case must be rescaled by a factor of [Formula: see text], and structures on the rescaled profile must be projected to the surface along diagonal lines to find their true positions. When three‐dimensional data are collected and automatic three‐dimensional migration is performed, the geometrical factors are inherently incorporated. In that case, the migration velocity is always equal to the true velocity regardless of whether the structure is two‐dimensional, plunging two‐dimensional, or three‐dimensonal. Processed model data support these conclusions. The equations given above are intended for use in conventional migration‐after‐stack. Recently developed schemes combining migration‐before‐stack with velocity analysis give [Formula: see text] directly. In that case, the above equations provide a method of determining [Formula: see text] from [Formula: see text].

SHEAR VISCOSITY OF STRONGLY-COUPLED TWO-DIMENSIONAL YUKAWA LIQUIDS: EXPERIMENT AND MODELING

2007 ◽  
Vol 21 (21) ◽  
pp. 1357-1376 ◽  
Author(s):  
Z. DONKÓ ◽  
P. HARTMANN ◽  
J. GOREE
Keyword(s):  
Shear Viscosity ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Simulation Studies ◽  
Strongly Coupled ◽  
Shear Rates ◽  
High Shear Rates ◽  
Wide Range ◽  
Computer Simulation Studies

This paper reviews experimental and modeling efforts aimed at the determination of the shear viscosity of strongly-coupled Yukawa liquids. After briefly reviewing prior work on three-dimensional (3D) systems, recent experimental and computer simulation studies of two-dimensional (2D) settings are presented in detail. In the experiments two counterpropagating laser beams were used to perturb a dusty plasma monolayer and monitoring of the velocity field reconstructed from particle trajectories allowed the determination of the shear viscosity with the aid of an analytical model. Subsequent computer simulations based on the molecular dynamics approach resulted in velocity profiles which are in very good agreement with the experimental ones. Further simulation studies of idealized 2D Yukawa liquids (in which gas friction is neglected) gave results for the shear viscosity over a wide range of system parameters and demonstrated the existence of the shear thinning effect (non-Newtonian behavior) of the liquid at high shear rates.

An Efficient Technique for Three-Dimensional Image Visualization Through Two-Dimensional Images for Medical Data

2017 ◽  
Vol 29 (1) ◽  
pp. 100-109
Author(s):  
Ganesan Gunasekaran ◽  
Meenakshisundaram Venkatesan
Keyword(s):  
Three Dimensional ◽  
Main Idea ◽  
Two Dimensional ◽  
3D Image ◽  
Image Visualization ◽  
Good Determination ◽  
The Given ◽  
Geometric Primitives ◽  
2D Images

Abstract The main idea behind this work is to present three-dimensional (3D) image visualization through two-dimensional (2D) images that comprise various images. 3D image visualization is one of the essential methods for excerpting data from given pieces. The main goal of this work is to figure out the outlines of the given 3D geometric primitives in each part, and then integrate these outlines or frames to reconstruct 3D geometric primitives. The proposed technique is very useful and can be applied to many kinds of images. The experimental results showed a very good determination of the reconstructing process of 2D images.

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