scholarly journals Speed Measurement in an Accomoving Reference System

2020 ◽  
Keyword(s):  
Reference Frame ◽  
Direct Measurement ◽  
Doppler Effect ◽  
Reference System ◽  
Radial Component ◽  
Wave Fronts ◽  
Peculiar Velocity ◽  
Peculiar Velocities ◽  
The Doppler Effect ◽  
Stellar Aberration

A method of direct measurement of the observer's velocity (peculiar velocity) relative to the accompanying reference system is proposed and investigated. To measure peculiar velocity, it is proposed to use the measurement of stellar light aberration. A comparison of the use of light aberration and the Doppler Effect for measuring velocity relative to relic radiation was made. When using the Doppler Effect, the total speed of the observer was measured - the Hubble speed and the radial component of the peculiar speed of the observer. As a result of the analysis of the components of the observer's velocity in the comoving reference frame, the Hubble and peculiar velocities of the observer, their essential features are formulated. The analysis of the shape of the wave fronts of the CMB radiation, the radiation of quasars, the radiation of stars and the radiation of ground sources is given. As a consequence of this analysis, the decisive influence of the shape of their wave fronts on the possibilities of measuring stellar aberration and the absence of such an effect when measuring velocity using the Doppler Effect are shown. Measurement of light aberration in an inertial system enables direct measurement of the observer's peculiar velocity in an comoving reference frame. Knowing the observer's peculiar velocity is important for increasing the accuracy of determining the Hubble velocity of especially objects of relatively small remoteness. The proposed structures of devices for measuring the peculiar velocity of an inertial reference system were investigated. Peculiar speed is determined by the measured light aberration without switching to another frame of reference. Their expected accuracy and reliability were evaluated. The practical use of the proposed structures is possible in astronomy and spacecraft.

scholarly journals Spiral Galaxies and the Peculiar Velocity Field

1996 ◽  
Vol 168 ◽  
pp. 183-191 ◽  
Author(s):  
Riccardo Giovanelli ◽  
Martha P. Haynes ◽  
Pierre Chamaraux ◽  
Luiz N. Da Costa ◽  
Wolfram Freudling ◽  
...  
Keyword(s):  
Velocity Field ◽  
Reference Frame ◽  
Large Scale ◽  
Local Group ◽  
Spiral Galaxies ◽  
Density Parameter ◽  
Compelling Evidence ◽  
Homogeneous Sample ◽  
Peculiar Velocity ◽  
Peculiar Velocities

We report results of a redshift-independent distance measurement survey that extends to all sky and out to a redshift of approximately 7500 km s−1. Tully–Fisher (TF) distances for a homogeneous sample of 1600 late spiral galaxies are used to analyze the peculiar velocity field. We find large peculiar velocities in the neighborhood of superclusters, such as Perseus–Pisces (PP) and Hydra–Centaurus, but the main clusters embedded in those regions appear to be virtually at rest in the CMB reference frame. We find no compelling evidence for large-scale bulk flows, whereby the Local Group, Hydra–Cen and PP would share a motion of several hundred km s−1with respect to the CMB. Denser sampling in the PP region allows a clear detection of infall and backflow motions, which can be used to map the mass distribution in the supercluster and to obtain an estimate of the cosmological density parameter.

scholarly journals Doppler effect described by the solutions of the Cattaneo telegraph equation

2020 ◽  
Author(s):  
Yuriy Povstenko ◽  
Martin Ostoja-Starzewski
Keyword(s):  
Doppler Effect ◽  
Heat Conduction Equation ◽  
Fourier Transforms ◽  
Telegraph Equation ◽  
Laplace And Fourier Transforms ◽  
Wave Fronts ◽  
Time Harmonic ◽  
The Doppler Effect ◽  
Harmonic Source ◽  
Steady State Solutions

AbstractThe Cattaneo telegraph equation for temperature with moving time-harmonic source is studied on the line and the half-line domain. The Laplace and Fourier transforms are used. Expressions which show the wave fronts and elucidate the Doppler effect are obtained. Several particular cases of the considered problem including the heat conduction equation and the wave equation are investigated. The quasi-steady-state solutions are also examined for the case of non-moving time-harmonic source and time-harmonic boundary condition for temperature.

scholarly journals On the Doppler effect in radar

Radiotekhnika ◽  
2021 ◽  
pp. 93-98
Author(s):  
O.V. Ryazantsev ◽  
S.V. Мarchenko ◽  
M.V. Kulik
Keyword(s):  
Doppler Shift ◽  
Doppler Effect ◽  
Beat Frequency ◽  
Radial Component ◽  
Engineering Systems ◽  
Total Speed ◽  
Radar Station ◽  
Doppler Effects ◽  
The Doppler Effect

The possibilities of simultaneous use of the longitudinal and transverse Doppler effects have been analyzed, and expressions have been derived for the corresponding beat frequencies between the emitted and received signals. As a rule, only the longitudinal Doppler effect is used in modern radio engineering systems, which makes it possible to determine the radial component of the object's speed. In addition, there are situations for which it is generally impossible to determine the speed of an object without taking into account the transverse Doppler effect. The authors analyze the fundamental possibilities of improving the functioning of radar stations that simultaneously use both types of Doppler effects – longitudinal and transverse ones – making it possible to determine the total speed of the observed object in any situations. The authors have analyzed the longitudinal and transverse Doppler effects for the case of a moving emitting object, derived expressions for the Doppler shift and expressions for the beat frequency in the case of an active radar station for both types of Doppler effects, which make it possible to obtain the value of the object's speed in any situations. Variants of determining the total speed of a moving object have been proposed, accounting the determination of its radial and tangential components. Idealized situations in which only one of the Doppler effects appeared have been considered.

The misunderstood Sagnac effect

2021 ◽  
Vol 34 (4) ◽  
pp. 480-485
Author(s):  
John-Erik Persson
Keyword(s):  
Doppler Effect ◽  
Order Effect ◽  
Second Order ◽  
Red Shift ◽  
Sagnac Effect ◽  
First Order ◽  
Pioneer Anomaly ◽  
The Doppler Effect ◽  
Stellar Aberration

The Sagnac effect of first order (in one-way light) is shown to explain the aberration observed in the very long base interferometry tests. This fact is also consistent with Sagnac’s results and with the observed stellar aberration. The Sagnac effect of second order (in two-way light) is shown to be real, but not observable, in the experiments that were done by Michelson and Morley. However, it is also shown that the same second order effect is observable in the Pioneer anomaly. The Doppler effect of second order is also demonstrated to explain the cosmic red shift, due to a radial ether wind.

scholarly journals Cosmicflows-2

2014 ◽  
Vol 11 (S308) ◽  
pp. 305-309
Author(s):  
R. Brent Tully ◽  
Hélène M. Courtois ◽  
Yehuda Hoffman ◽  
Daniel Pomarède
Keyword(s):  
Three Dimensional ◽  
Wiener Filter ◽  
Radial Component ◽  
Density Field ◽  
Distance Measurements ◽  
Entire Domain ◽  
Cosmic Expansion ◽  
Peculiar Velocity ◽  
Peculiar Velocities

AbstractA compendium of over 8000 galaxy distances has been accumulated. Distance measurements permit the separation of observed velocities into cosmic expansion and peculiar velocity components. Only the radial component of peculiar velocities can be measured and individual errors are large, but a Wiener Filter procedure permits the reconstruction of three-dimensional motions and the density field that is responsible for these motions. A coherent flow pervades the entire domain of ± 15,000 km/s. Techniques are discussed for the separation of local and tidal components of the flow. Laniakea supercluster is identified as a region of contiguous infalling flows.

scholarly journals Improving the dynamical reference frame through minor planet orbit correction using crossing point observations

1988 ◽  
Vol 128 ◽  
pp. 55-60
Author(s):  
Arthur L. Whipple ◽  
Raynor L. Duncombe ◽  
Paul D. Hemenway
Keyword(s):  
Computer Program ◽  
Reference Frame ◽  
Reference System ◽  
Hubble Space Telescope ◽  
Simulated Data ◽  
Minor Planet ◽  
Minor Planets ◽  
Space Telescope ◽  
Orbit Correction ◽  
Crossing Point

We have begun a program to establish a dynamical reference frame based on the motions of minor planets. The program will utilize observations from the Hubble Space Telescope, and will ultimately tie the HIPPARCOS reference system to a dynamical base. Thirty-four minor planets, 20 of which are suitable for observation with the Hubble Space Telescope, have been selected. Ground based observations, particularly crossing-point observations with long focus reflectors, have been initiated.A computer program to simultaneously solve for the corrections of the orbits of the 34 minor planets including the crossing-point observations, was successfully run. The observations are treated by the method of W. H. Jeffreys. Using simulated data, solutions with and without crossing point observations demonstrate the value of those observations to produce a homogeneous and coherent set of results.

scholarly journals The Celestial Reference System in Relativistic Framework

1990 ◽  
Vol 141 ◽  
pp. 99-110
Author(s):  
Han Chun-Hao ◽  
Huang Tian-Yi ◽  
Xu Bang-Xin
Keyword(s):  
Coordinate System ◽  
Reference Frame ◽  
Reference System ◽  
Light Deflection ◽  
Coordinate Systems ◽  
Definition Of ◽  
Celestial Sphere ◽  
Celestial Reference System ◽  
Relativistic Framework

The concept of reference system, reference frame, coordinate system and celestial sphere in a relativistic framework are given. The problems on the choice of celestial coordinate systems and the definition of the light deflection are discussed. Our suggestions are listed in Sec. 5.

ON THE THEORY OF THE DOPPLER EFFECT IN A MOVING MEDIUM

1998 ◽  
Vol 13 (01) ◽  
pp. 1-6 ◽  
Author(s):  
BRUNO BERTOTTI
Keyword(s):  
Solar Wind ◽  
Doppler Effect ◽  
Dispersive Medium ◽  
Time Derivative ◽  
Optical Path ◽  
Moving Medium ◽  
Perturbation Theorem ◽  
Hamiltonian Theory ◽  
The Doppler Effect ◽  
Definition Of

The increase in the accuracy of Doppler measurements in space requires a rigorous definition of the observed quantity when the propagation occurs in a moving, and possibly dispersive medium, like the solar wind. This is usually done in two divergent ways: in the phase viewpoint it is the time derivative of the correction to the optical path; in the ray viewpoint the signal is obtained form the deflection produced in the ray. They can be reconciled by using the time derivative of the optical path in the Lagrangian sense, i.e. differentiating from ray to ray. To rigorously derive this result an understanding, through relativistic Hamiltonian theory, of the delicate interplay between rays and phase is required; a general perturbation theorem which generalizes the concept of the Doppler effect as a Lagrangian derivative is proved. Relativistic retardation corrections O(v) are obtained, well within the expected sensitivity of Doppler experiments near solar conjunction.

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