EVALUATION AND COMPENSATION OF SYSTEMATIC ERRORS OF CALIBRATION OF MATRIX SIMULATOR

2018 ◽  
pp. 24-28
Author(s):  
A. V. Kiselev ◽  
A. O. Podkopaev ◽  
M. A. Stepanov
Keyword(s):  
Phase Error ◽  
Precise Determination ◽  
Random Component ◽  
Compensation Error ◽  
The Matrix ◽  
Calibration Algorithm ◽  
Phase Calibration ◽  
Analytical Relations ◽  
Theoretical Results

The problem of phase calibration of the matrix simulator is considered. The phase error at the point of reception is divided into systematic and random. Analytic relationships are obtained that allow one to evaluate and compensate for the systematic error in the calibration of the phases of the signals emitted by the matrix simulator, caused by the geometric separation of the phase centers of the antenna and the antenna of the calibration receiver. The random component of the phase error is compensated by the calibration algorithm. Analytical relations are obtained for determining the compensation error due to the non-precise determination of the coordinates of the emitting part of the matrix simulator and the phase center of the antenna of the measuring receiver. The magnitude of this error is determined for the typical location of the antennas of the device under investigation, the measuring receiver and the matrix simulator when performing semi-realistic simulation. The description of the laboratory stand of the developer of the matrix imitator is given. The obtained theoretical results are confirmed experimentally at the booth of the matrix imitator developer.

scholarly journals Determination of the parameters of a four-point partially coherent model of radar object based on its equivalence to a five-point non-coherent model

2019 ◽  
Vol 29 (4) ◽  
pp. 35-43
Author(s):  
A. O. Podkopayev ◽  
M. A. Stepanov ◽  
S. V. Tyrykin
Keyword(s):  
Geometric Model ◽  
Software Modeling ◽  
Point Model ◽  
Partially Coherent ◽  
Object Based ◽  
The Matrix ◽  
Analytical Relations ◽  
Correlated Signals ◽  
Theoretical Results

The problem of determining the parameters of a four-point partially coherent model of radar object based on its equivalence to a five-point non-coherent model was solved. The obtained analytical relations describe the spectral and correlation characteristics of signals delivered to the emitters of the four-point partially coherent model of the matrix simulator emitting statistically dependent normal random processes. Correlations are defined based on the equivalence of a four-point model emitting correlated signals and five-point model emitting uncorrelated signals. Moreover, the projections of an original five-point non-coherent model onto two mutually orthogonal coordinate axes are reviewed. Based on that, the projections onto the same axes of a four-point partially coherent model are derived. Expressions relating to the derived projections and required four-point partially coherent model are obtained. Conditions that are necessary for the synthesis of an adequate five-point non-coherent distributed radar target geometric model are described. Based on them, the limitations within which a transition from non-coherent five-point models to partially coherent four-point models is possible are formulated. The obtained theoretical results are confirmed by software modeling.

scholarly journals Phasing errors of the matrix simulator of the echo signals of the multi-antenna radar system

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
M.A. Stepanov ◽  
◽  
T.I. Sabitov ◽  
A.V. Kiselev
Keyword(s):  
Phase Error ◽  
Antenna System ◽  
Maximum Phase ◽  
Worst Case ◽  
Phase Errors ◽  
Radar Systems ◽  
The Matrix ◽  
Simulation Errors ◽  
Theoretical Results ◽  
Receive Antenna

This work is devoted to the study of phasing errors of a matrix simulator focused on several receiving points. Errors arising during signal calibration are considered. The phase error compensation procedure is designed for matrix simulators used to simulate echoes for a single receive antenna. It allows to align the phases of the simulator signals and eliminate simulation errors caused by phase errors. It is shown that this procedure does not allow to eliminate phasing errors simultaneously for several receiving antennas. The case of a two-antenna system and a matrix of two emitters is considered. For this case, a relation was obtained for calculating the phase correction, which minimizes the phasing error of the signals. Herewith the magnitude of the error depends on the magnitude of the random displacements of the emitters from the required positions. For a given emitter positioning accuracy, the worst case is investigated, which corresponds to the maximum phase error. Relationships are obtained to estimate this error. On the basis of these relations, the ways of its minimization are established. For a larger number of emitters, a relation is obtained for calculating the maximum possible phasing error. The results obtained can be extended to the case of a larger number of receiving antennas. In order to verify the theoretical results a matrix of two emitters was developed focused on two receiving points. A number of numerical experiments have been carried out, the results of which have confirmed the reliability of the obtained relationships. The results of this work are practically significant, since they determine the requirements for the configuration of the matrix simulator. They allow to determine whether the required phasing can be provided for a given matrix. They can be used in the development of matrix simulators of echo signals of multi-antenna radar systems.

Lateral resolution of the electron microbeam analysis

1978 ◽  
Vol 36 (1) ◽  
pp. 542-543
Author(s):  
H.J. Dudek
Keyword(s):  
Quantitative Analysis ◽  
Depth Resolution ◽  
Lateral Resolution ◽  
Cylindrical Particle ◽  
Correction Procedure ◽  
X Ray ◽  
Element Concentrations ◽  
Microbeam Analysis ◽  
The Matrix

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S

Determination of the phase structure of polymerblends by electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 492-493
Author(s):  
Dr. G. Kaemof
Keyword(s):  
Screw Extruder ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Single Screw Extruder ◽  
Transmission Electron ◽  
The Matrix ◽  
Twin Screw ◽  
Special Case ◽  
Microscopic Investigations

A mixture of polycarbonate (PC) and styrene-acrylonitrile-copolymer (SAN) represents a very good example for the efficiency of electron microscopic investigations concerning the determination of optimum production procedures for high grade product properties.The following parameters have been varied:components of charge (PC : SAN 50 : 50, 60 : 40, 70 : 30), kind of compounding machine (single screw extruder, twin screw extruder, discontinuous kneader), mass-temperature (lowest and highest possible temperature).The transmission electron microscopic investigations (TEM) were carried out on ultra thin sections, the PC-phase of which was selectively etched by triethylamine.The phase transition (matrix to disperse phase) does not occur - as might be expected - at a PC to SAN ratio of 50 : 50, but at a ratio of 65 : 35. Our results show that the matrix is preferably formed by the components with the lower melting viscosity (in this special case SAN), even at concentrations of less than 50 %.

Polishing process effect on the image of dispersed precipitates

1984 ◽  
Vol 42 ◽  
pp. 534-535
Author(s):  
C.T. Hu ◽  
C.W. Allen
Keyword(s):  
Matrix Material ◽  
Specimen Preparation ◽  
Second Phase ◽  
Precipitate Particle ◽  
Polishing Process ◽  
Second Phase Particles ◽  
The Matrix ◽  
Surface Profiles ◽  
Thinning Process

One important problem in determination of precipitate particle size is the effect of preferential thinning during TEM specimen preparation. Figure 1a schematically represents the original polydispersed Ni3Al precipitates in the Ni rich matrix. The three possible type surface profiles of TEM specimens, which result after electrolytic thinning process are illustrated in Figure 1b. c. & d. These various surface profiles could be produced by using different polishing electrolytes and conditions (i.e. temperature and electric current). The matrix-preferential-etching process causes the matrix material to be attacked much more rapidly than the second phase particles. Figure 1b indicated the result. The nonpreferential and precipitate-preferential-etching results are shown in Figures 1c and 1d respectively.

PRECISE DETERMINATION OF THE IRRATIONAL PRE-FERRED INTERFACE ORIENTATION BY TEM

2010 ◽  
Vol 46 (4) ◽  
pp. 411-417 ◽  
Author(s):  
Yang MENG ◽  
Lin GU ◽  
Wenzheng ZHANG
Keyword(s):  
Precise Determination ◽  
Interface Orientation

Nauwkeurige methode voor de aanwasbepaling van het grondvlak met behulp van de Pressler-boor

1968 ◽  
Vol 12 ◽  
Author(s):  
R. Goossens
Keyword(s):  
Basal Area ◽  
Precise Determination ◽  
Maximum Diameter ◽  
Precise Method ◽  
Maximum Radius ◽  
The Core ◽  
Two Parameters

A precise method for the determination of the increment of the  basal area using the PressIer bore. Refering to  previous research showing that the basal area of the corsica pine could be  characterized by an ellips, we present in this paper a precise method for the  determination of the increment of the basal area. In this method we determine  the direction of the maximum diameter, we measure this diameter and we take a  core in one of the points of tangency of the caliper with the measured tree.  The determination of the diameter perpendicular to the maximum diameter  finishes the work wich is to be done in the forest. From the classical  measurements effectuated on the core and from the measured diameters we can  then determine the form (V) and the excentricity (e). Substituting these two  parameters in the formula 2 or 2', we can also calculate the error of a  radius measured on the core with respect to the representative radius, This  error with them allow us to correct the measured value of the minimum or the  maximum radius and we will be able to do a precise determination of the  increment.

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