scholarly journals TYPHOON A DEVICE FOR MEASUREMENT AND REGISTRATION OF CHANGE OF THE ANGULAR COORDINATE OF THE OBJECT IN PLANE

2018 ◽  
pp. 27-32
Author(s):  
E. V. Romanova
Keyword(s):  
Angular Coordinate

scholarly journals Accuracy Characteristics of the Parametric Burg Method for Spatial Signal Processing in a Nonuniform Array Antenna

2021 ◽  
Vol 24 (3) ◽  
pp. 60-71
Author(s):  
V. M. Kutuzov ◽  
M. A. Ovchinnikov ◽  
E. A. Vinogradov
Keyword(s):  
Signal Processing ◽  
Computer Modelling ◽  
Asymptotic Bounds ◽  
Angular Coordinate ◽  
Receiving Antenna ◽  
Spatial Signal Processing ◽  
Reflected Signal ◽  
Maximum Likelihood Estimations ◽  
Angular Coordinates ◽  
Random Step

Introduction. In the case of a nonuniform (NU) design of the antenna elements (AEs) of the receiving antenna array (AA), the antenna pattern (AP) features sidelobes (SL) with a significantly higher noise level than acceptable values. Under low signal-to-noise ratios (SNR), this noise leads to angular coordinate measuring errors thus worsening the statistical accuracy characteristics (ACs) of the signal. It is of relevance to construct the ACs of angular coordinates when a modified parametric Burg method (BM) is applied to spatial reflected signal processing in a transportable decametre range radar (DRR) with a nonuniform array (NUA) and linear accuracy characteristics. Aim. To analyse the statistical ACs of angular coordinate objects when using a modified BM for spatial reflected signal processing in a DRR with a linear NUA, in which AEs are located with a random step in the range from λ/2 to several λ, where λ is the operating carrier wavelength.Materials and methods. Statistical ACs were constructed by computer modelling in the MatLab software, the reliability of which was confirmed by conventional discrete Fourier transform methods, as well as by comparing the obtained ACs with asymptotic bounds, including Cramer-Rao bounds.Results. The possibility and conditions of using a modified parametric BM for estimating the azimuthal coordinates of reflected radar signals were determined for the case of a nonuniform design of the over-the-horizon DRR receiving AA AEs. Statistical ACs were obtained and compared with the asymptotically optimal ACs of the maximum likelihood estimations corresponding to the uniform AE design.Conclusion. The obtained results confirm the suboptimality of the BM modified for signal processing in the NUA at a random AE spacing step in the range from λ/2 to 2λ, making it applicable for use in transportable DRRs.

A System of Notation and Measurement for Space Suit Mobility Evaluation

1968 ◽  
Vol 10 (1) ◽  
pp. 79-93 ◽  
Author(s):  
John A. Roebuck
Keyword(s):  
Integrated System ◽  
The Body ◽  
Human Engineering ◽  
Space Suit ◽  
Body Movements ◽  
Angular Coordinate ◽  
Workspace Analysis ◽  
Wide Range ◽  
And Control ◽  
Standard Techniques

An integrated system of mobility notation and standard techniques for measurement of spacesuit mobility is described. New terminology is proposed to describe human body movements for engineering workspace analysis and suit mobility specifications. Vector and link concepts are combined in a simplified model of man to describe body positions in terms of orientation of limbs with respect to a tri-planar angular coordinate system conceived as attached to the pelvic region. Numerical coding of the body links and joints is described. The notation system may be used as a basis for mathematical modeling for computer analysis of vehicle workspace geometry and control locations. The system is independent of gravitational reference semantic implications and sufficiently general for a wide range of complexity in kinesiological, medical, and human engineering applications.

Quantum Description of the Angular Coordinate and Angular Momentum

2011 ◽  
Author(s):  
Stephen M. Barnett ◽  
Alison M. Yao ◽  
Filippo M. Miatto ◽  
L. Allen ◽  
David T. Pegg ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Quantum Description ◽  
Angular Coordinate

Potential functions with periodicity in one coordinate

1934 ◽  
Vol 30 (3) ◽  
pp. 315-326 ◽  
Author(s):  
R. C. J. Howland
Keyword(s):  
Boundary Conditions ◽  
Potential Functions ◽  
The Other ◽  
Boundary Values ◽  
Angular Coordinate ◽  
General Conception

The general conception underlying the following analysis is that of a field of potential which is invariant under a group of geometrical transformations. The boundary is to consist of a number of parts which transform into each other and the boundary values also transform into each other. To satisfy the conditions we build up functions which are invariant under the same group of transformations and combine them to give the prescribed boundary values over one section of the boundary. The boundary conditions on the other sections are then automatically satisfied. When the groups are simply translations or rotations we get functions periodic in either a Cartesian or an angular coordinate.

Calculation of the stress state of a noncircular helicoidal tube based on the tensor theory of shells

2021 ◽  
Author(s):  
A.G. Sorokina ◽  
V.A. Kirsanova ◽  
V.F. Fomicheva
Keyword(s):  
Strain Energy ◽  
Nabla Operator ◽  
Angular Coordinate ◽  
Total Potential ◽  
Tensor Theory ◽  
Displacement Vectors ◽  
Helicoidal Surface ◽  
Deformed State ◽  
Set Of Points ◽  
Theory Of Shells

The purpose of the study was to develop an algorithm for calculating helical-symmetric shells with a closed contour in oblique Gaussian coordinates. The twist and length of the shell were taken unchanged. The method is based on the representation of the generating contour of the helicoidal surface by a discrete set of points with the replacement of differentiation along the angular coordinate by finite differences. The unknown were the displacement vectors at the indicated points of the contour. Due to the helicoidal symmetry, the differentiation of vector quantities with respect to the helical coordinate was replaced by vector multiplication. The tensor of deformations and the tensor of the parameters of the change in curvature were calculated using the nabla operator, represented in oblique Gaussian coordinates. Integration over the contour coordinate was replaced by summation over discrete points. The tensors found, which characterize the deformed state, were used to calculate the strain energy of one period of the helicoidal shell, and then the total potential of the mechanical system was compiled. The unknown displacements were determined by minimizing the total potential, taking into account the constraints that prohibit the displacement of the shell as a rigid whole. The study gives a numerical example of the application of the developed approach.

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