Hybrid Systems for Use in the Dynamics of Artificial Satellites

1975 ◽  
Vol 26 ◽  
pp. 235-240
Author(s):  
Y. Kozai
Keyword(s):  
Hybrid Systems ◽  
Review Paper ◽  
Artificial Satellites ◽  
Reference Systems ◽  
Coordinate Systems ◽  
Orbital Elements

AbstractFor observed positions ofi artificial satellites and their orbital elements, many kinds of reference coordinate systems have been available. Some are more convenient for reductions of observations, while others are more convenient for analyzing the orbital elements for geodesy. In this review paper, perturbations produced owing to the adoption of diffrent kinds of reference systems are discussed.

scholarly journals Motions of Artificial Satellites and Coordinate Systems

1980 ◽  
Vol 56 ◽  
pp. 233-237
Author(s):  
Yoshihide Kozai
Keyword(s):  
Reference System ◽  
Artificial Satellites ◽  
Reference Systems ◽  
Coordinate Systems ◽  
Advantages And Disadvantages

AbstractIn order to compute satellite motions with centimeter accuracy, the reference system, to which they are referred, should be carefully chosen. In fact there are many kinds of the reference systems. In this paper advantages and disadvantages of various reference systems are discussed.

Artificial satellite orbit computations

1966 ◽  
Vol 25 ◽  
pp. 363-371
Author(s):  
P. Sconzo
Keyword(s):  
Artificial Satellite ◽  
Satellite Orbit ◽  
Artificial Satellites ◽  
Orbital Elements ◽  
Differential Correction ◽  
Gravitational Effects ◽  
Short Intervals ◽  
The Subject ◽  
Introductory Discussion ◽  
Orbit Computation

In this paper an orbit computation program for artificial satellites is presented. This program is operational and it has already been used to compute the orbits of several satellites.After an introductory discussion on the subject of artificial satellite orbit computations, the features of this program are thoroughly explained. In order to achieve the representation of the orbital elements over short intervals of time a drag-free perturbation theory coupled with a differential correction procedure is used, while the long range behavior is obtained empirically. The empirical treatment of the non-gravitational effects upon the satellite motion seems to be very satisfactory. Numerical analysis procedures supporting this treatment and experience gained in using our program are also objects of discussion.

scholarly journals The Reference Systems

1979 ◽  
Vol 82 ◽  
pp. 151-163 ◽  
Author(s):  
J. Kovalevsky
Keyword(s):  
Observational Constraints ◽  
Reference Systems ◽  
Coordinate Systems ◽  
The Earth

In order to discuss accurately the motions of the Earth in space, it is necessary to define rigorously two readily accessible reference systems. The conception and the realization of celestial absolute systems and terrestrial coordinate systems are discussed. It is suggested that these systems of reference ought to be defined with a minimum of theoretical or observational constraints. Examples of such ideal reference systems are given, together with some desirable properties for intermediate systems.

Magnitudes and Spectra of Important Dynamical Phenomena

1975 ◽  
Vol 26 ◽  
pp. 63-77
Author(s):  
E. P. Fedotov
Keyword(s):  
Polar Motion ◽  
Continental Drift ◽  
Earth’S Rotation ◽  
Reference Systems ◽  
Coordinate Systems ◽  
Gravitation Field ◽  
Earth's Rotation ◽  
The Earth ◽  
Rigid Attachment ◽  
Body Tides

AbstractThe axes of coordinate systems used in geodynamics are believed to be attached to a number of physical points on the surface of the Earth. This is true when measurements of the distances (ranging) are dealt with. On the other hand, the axes of reference systems used by the BIH and IFMS are attached not to the points themselves but to a pencil of plumb lines at these points. For the case of observations with radio interferometers being used for the study of Earth’s rotation, the rotating frame of reference could be attached in some prescribed way toihebaselines of the interferometers.But in no case is rigid attachment possible, because both the above points and lines move relative to each other. We should search for another way to define the reference systems for geodynamics. With that end in view, a knowledge of magnitudes of pertinent dynamical phenomena becomes vital.This paper considers the effects of some dynamical phenomena upon the distances between the points on. the Earth’s surface and upon the angles between plumb lines and, possibly, also between baselines of radio interferometers. In particular, this paper discusses body tides, continental drift, internal motion within crustal blocks, redistribution of mass which can affect the directions of plumb lines, etc. Polar motion and variations in the rate of Earth’s rotation will be also touched upon as far as these phenomena contribute to deformation of the Earth and its gravitation field.The results are summarised in diagrams showing how the variations of the above distances and angles depend upon both time and positions on the Earth. In other words, the power spectrum of the variation will be presented as a function of time and distance expressed either in kilometers or in degrees of arc on the Earth’s surface.

scholarly journals Reference Frame Studies at JPL/Caltech

1986 ◽  
Vol 7 ◽  
pp. 93-96
Author(s):  
J. O. Dickey ◽  
P. B. Esposito ◽  
J.-F. Lestrade ◽  
R. P. Linfield ◽  
W. G. Melbourne ◽  
...  
Keyword(s):  
Reference Frame ◽  
Artificial Satellites ◽  
Radio Sources ◽  
Coordinate Systems ◽  
New Techniques ◽  
Long Baseline ◽  
Celestial Bodies ◽  
Spacecraft Tracking ◽  
Orbiting Spacecraft ◽  
Radar Ranging

In recent years, a revolution in astronomical position measurements has been taking place with the advent of modern space techniques. These new techniques, which supplement the traditional astrometric measurements, include laser ranging to the moon and artificial satellites, very-long-baseline interferometry (VLBI) of galactic and extra-galactic radio sources and spacecraft, radio tracking of satellites, and radar-ranging and spacecraft tracking during planetary encounters. Impressive accuracies have been achieved and further improvements are forthcoming. Each technique can be expected to establish its own reference frame which is derived from observations of a particular class of objects. The celestial and terrestrial coordinate systems are related through adopted constants and definitions. Contemporary astronomy has led to the development of three principal celestial coordinate systems: the optical frame (FK4/FK5) based on positions of galactic stars; the planetary/lunar ephemeris frame based on the major celestial bodies of the solar system; and the radio frame constructed from observations of extragalactic radio sources (quasars). Each frame is rotated with respect to others; furthermore, the optical frame offset is time variable. It is important that all frames be interconnected and unified. The optical frame is being connected to the radio frame by VLBI observations of radio emitting stars. The radio frame is being tied to the ephemeris frame in several ways – one is via differential VLBI measurements between quasars and planet-orbiting spacecraft.

scholarly journals Post-Newtonian direct and mixed orbital effects due to the oblateness of the central body

2015 ◽  
Vol 24 (08) ◽  
pp. 1550067 ◽  
Author(s):  
L. Iorio
Keyword(s):  
Test Particle ◽  
Central Body ◽  
Symmetry Axis ◽  
Equations Of Motion ◽  
Mixed Effects ◽  
Orbital Dynamics ◽  
Artificial Satellites ◽  
Orbital Elements ◽  
Zonal Harmonic ◽  
Orbital Configuration

The orbital dynamics of a test particle moving in the nonspherically symmetric field of a rotating oblate primary is impacted also by certain indirect, mixed effects arising from the interplay of the different Newtonian and post-Newtonian accelerations which induce known direct perturbations. We systematically calculate the indirect gravitoelectromagnetic shifts per orbit of the Keplerian orbital elements of the test particle arising from the crossing among the first even zonal harmonic J2 of the central body and the post-Newtonian static and stationary components of its gravitational field. We also work out the Newtonian shifts per orbit of order [Formula: see text], and the direct post-Newtonian gravitoelectric effects of order J2c-2 arising from the equations of motion. In the case of both the indirect and direct gravitoelectric J2c-2 shifts, our calculation holds for an arbitrary orientation of the symmetry axis of the central body. We yield numerical estimates of their relative magnitudes for systems ranging from Earth's artificial satellites to stars orbiting supermassive black holes. As far as their measurability is concerned, highly elliptical orbital configuration are desirable.

scholarly journals Comments on Recommendation III of the IAU Working Group on Reference Systems

1992 ◽  
Vol 9 ◽  
pp. 151-153
Author(s):  
E.M. Standish
Keyword(s):  
Time Scale ◽  
Working Group ◽  
Reference Systems ◽  
Orbital Elements ◽  
Lunar Satellite ◽  
Scientific Results

IAU Recommendations should 1) help to avoid confusion and 2) help to enhance scientific capability. Recommendation III does neither. It would create confusion while doing nothing to improve scientific results.If Recommendation III is ever implemented, the result will be sheer chaos. This recommendation proposes that the rate of the basic ephemeris time scale be changed – by an amount of nearly one-half second per year. This implies that all existing planetary, lunar, satellite, spacecraft, asteroid and comet ephemerides would be referenced to an obsolete time scale; all existing sets of orbital elements would need a modification; that epoch J2000 (JED 2451545.0) would differ from the presently defined one by nearly 15 seconds.

scholarly journals Permanent Milliarcsecond Link of Celestial and Terrestrial Reference Systems

1991 ◽  
Vol 127 ◽  
pp. 101-107
Author(s):  
M. Feissel
Keyword(s):  
Reference System ◽  
Artificial Satellites ◽  
Radio Sources ◽  
Reference Systems ◽  
International Earth Rotation Service ◽  
Earth Orientation Parameters ◽  
Long Baseline ◽  
The Earth ◽  
Celestial Reference System ◽  
Orientation Parameters

AbstractThe celestial reference system and the terrestial reference system of the International Earth Rotation Service (IERS) are realized on the basis of observation programs in Very Long Baseline radio Interferometry and laser ranging to the Moon and artificial satellites. The celestial frame is materialized by the equatorial coordinates of radio sources observed in VLBI; the terrestrial frame is materialized by the cartesian coordinates of the terrestrial sites monitored by the three techniques. Series of the Earth Orientation Parameters are derived from the same observations. These series provide a permanent link between the celestial system and the terrestrial system at the level of 0.001”.The global adjustment in which the reference systems are defined and realized is described, and the metrological properties of the frames and of the derived EOP are evaluated.

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