GPS Satellite State Vector Determination in ECI Coordinate System using the Civil Navigation Message

2013 ◽  
Vol 67 (1) ◽  
pp. 1-16
Author(s):  
Ghangho Kim ◽  
Sanghoon Jeon ◽  
Changdon Kee ◽  
Tae Soo No ◽  
Kiho Kwon ◽  
...  
Keyword(s):  
Closed Form ◽  
Reference Frame ◽  
Calculated Data ◽  
Terrestrial Reference Frame ◽  
Navigation Data ◽  
Numerical Result ◽  
Resolution System ◽  
Satellite Velocity ◽  
Celestial Reference Frame ◽  
Simple Rotation

A closed form of an algorithm to determine a Global Positioning System (GPS) satellite's position, velocity and acceleration is proposed, and an Earth Centred Earth Fixed (ECEF) to Earth Centred Inertial (ECI) transformation result using the Civil Navigation (CNAV) message is presented in this paper. To obtain the closed form of the GPS satellite velocity and acceleration determination algorithm using the CNAV, we analytically differentiated the IS-GPS-200F position determination function. The calculated data are transformed from the International Terrestrial Reference Frame (ITRF) to the Geocentric Celestial Reference Frame (GCRF) using an equinox-based transform algorithm that is defined in the IAU-2000 resolution system using the Earth Orientation Parameter (EOP) data. To verify the correctness of the proposed velocity and acceleration determination algorithm, the analytical results are compared to the numerical result. The equinox-based transformation result is compared to simple rotation about the z-axis, which does not use the EOP. The results show that by using the proposed algorithm and the equinox-based transformation together, the user can obtain more accurate navigation data in the ECI frame.

scholarly journals Formation of The International Celestial Reference Frame

1998 ◽  
Vol 11 (1) ◽  
pp. 281-286
Author(s):  
C. Ma ◽  
E.F. Arias ◽  
T.M. Eubanks ◽  
A.L. Fey ◽  
A.-M. Gontier ◽  
...  
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Terrestrial Reference Frame ◽  
Naval Research ◽  
Dual Frequency ◽  
Cooperative Effort ◽  
Space Navigation ◽  
Vlbi Observations ◽  
Crustal Dynamics ◽  
Celestial Reference Frame

The goal of the work described here is to create the definitive catalogue for the new International Celestial Reference Frame (ICRF) using the best data and methods available at the time the work was done. This work is the joint cooperative effort of a subgroup of the IAU Working Group on Reference Frames which was formed expressly for this purpose in February 1995. The authors of this report constituted the subgroup. A fuller account of this report can be found in the introduction to the ICRF catalog (IERS 1997). The ICRF of 608 sources presented here is based on essentially all the VLBI observations accu-mulated over about 15 years in several worldwide programs. Dual frequency Mark III data have both geodetic and astrometric applications. Most of the data (95% of nearly 2 million observations) were acquired primarily for geodetic purposes. The major geodetic programs include: NASA’s Crustal Dynamics Project/Space Geodesy Program and USNO’s NAVEX sessions for the terrestrial reference frame, as well as IRIS, NAVNET and NEOS sessions for monitoring Earth rotation. The geodetic programs have used the brightest radio sources, gradually concentrating on the most com-pact as sensitivity improved. These geodetic sources were also the foundation of astrometric work because of the large number of observations for the ~150 most commonly used. The astrometric programs which densify the sky include the Radio-Optical Reference Frame sessions done by US Naval Research Laboratory (NRL) and USNO and the space navigation efforts of Jet Propulsion Laboratory (JPL).

scholarly journals CQSSP: A New Technique for Establishing the Tie Between the Stellar and Quasar Celestial Reference Frames

1991 ◽  
Vol 127 ◽  
pp. 341-347
Author(s):  
T. Schildknecht ◽  
I. Bauersima ◽  
U. Hugentobler ◽  
A. Verdun ◽  
G. Beutler
Keyword(s):  
Reference Frame ◽  
Earth Rotation ◽  
Reference Frames ◽  
Terrestrial Reference Frame ◽  
Optical Observations ◽  
Artificial Satellites ◽  
Satellite Orbits ◽  
Earth Rotation Parameters ◽  
A New Technique ◽  
Celestial Reference Frame

AbstractUsing artificial satellites as transfer objects the project “Coupled Quasar-Satellite-Star Positioning” represents an independent method for linking quasar and stellar reference frames. Optical observations of close approaches between reference stars and satellites yield satellite positions in the stellar reference frame. On the other hand high precision satellite orbits in the International Earth Rotation Service (IERS) terrestrial reference frame are obtained from laser or radiometric observations. Using IERS earth rotation parameters and adopted transformation models the satellite and eventually the star positions can be expressed in the IERS quasar celestial reference frame. In this paper we describe the CQSSP project and assess its capability for providing an accurate tie between tho two metioned celestial reference frames.

scholarly journals Improvement and Maintenance of the Extragalactic Reference Frame

1995 ◽  
Vol 166 ◽  
pp. 284-284
Author(s):  
E.F. Arias ◽  
A.M. Gontier
Keyword(s):  
Reference Frame ◽  
Polar Axis ◽  
Terrestrial Reference Frame ◽  
Lunar Laser Ranging ◽  
The Best Approximation ◽  
Long Baseline ◽  
Lunar Laser ◽  
Celestial Reference Frame ◽  
Better Than

Very Long Baseline Interferometry (VLBI) is at present the most powerful technique to construct the best approximation to an inertial reference frame. After more than a decade of VLBI observations several hundreds of extragalactic objects have positions known within ±0.0003″. Since 1988 the International Earth Rotation Service (IERS) elaborates a global extragalactic celestial reference frame (IERS Celestial Reference Frame, ICRF) that is tied to the international terrestrial reference frame through the high precision monitoring of the Earth's rotation. The direction of the ICRF axes relative to the IAU definitions are known within better than ±0.001″ for the polar axis and ±0.003″ for the origin of right ascensions. The FK5 axes are consistent with the ICRF ones within their uncertainties (0.050″-0.100″). The maintenance of this high accuracy extragalactic frame will be necessary for the long term programs, such as the future monitoring of the tie of the Hipparcos galactic frame as well as of the dynamical planetary frame (millisecond pulsars, lunar laser ranging).

scholarly journals The Contribution of the IERS to Astrophysics and Geodynamics

1993 ◽  
Vol 156 ◽  
pp. 406-406
Author(s):  
M. Feissel ◽  
Yaroslav Yatskiv
Keyword(s):  
Reference Frame ◽  
Global Positioning System ◽  
Terrestrial Reference Frame ◽  
International Earth Rotation Service ◽  
Earth Orientation Parameters ◽  
Long Baseline ◽  
The Earth ◽  
Global Positioning ◽  
Orientation Parameters ◽  
Celestial Reference Frame

The International Earth Rotation Service (IERS) maintains a celestial reference frame and a terrestrial reference frame based on observations in Very Long Baseline radio Interferometry, Lunar and Satellite Laser Ranging, and Global Positioning System, as well as a time series of the Earth Orientation Parameters in a system that is consistent at the level of 0.001″.

scholarly journals Commision 19: Earth Rotation (Rotation de la Terre)

1991 ◽  
Vol 21 (1) ◽  
pp. 169-186
Keyword(s):  
Reference Frame ◽  
Earth Rotation ◽  
Very Long Baseline Interferometry ◽  
International Association ◽  
High Accuracy ◽  
Terrestrial Reference Frame ◽  
International Earth Rotation Service ◽  
Long Baseline ◽  
Compact Sources ◽  
Celestial Reference Frame

The period has been marked by the start of the new International Earth Rotation Service (IERS), which benefits from a tight cooperation between astronomers, geodesists, and specialists in satellite geodesy, as well as meteorologists. The scope of the IERS covers not only the Earth’s rotation per se, but also the conventional terrestrial reference frame, of direct interest to the International Association of Geodesy, and a high accuracy (0.001”) celestial reference frame based on extragalactic compact sources observed in Very Long Baseline Interferometry. The IERS conventional celestial reference frame is consistent with the FK5 within the uncertainties of the latter (0.04”). The IERS Standards (1989) which contain the current best estimates of astronomical models and constants are used in many fields of astronomy and geodesy.

scholarly journals The Accuracy of the ICRF: an Intercomparison of VLBI Analysis Software

1998 ◽  
Vol 11 (1) ◽  
pp. 320-321
Author(s):  
C.S. Jacobs ◽  
O.J. Sovers ◽  
D. Gordon ◽  
C. Ma ◽  
A.-M. Gontier
Keyword(s):  
Reference Frame ◽  
Internal Consistency ◽  
Significant Loss ◽  
Physical Parameters ◽  
Software Packages ◽  
Differential Group ◽  
Radio Signals ◽  
Least Squares Adjustment ◽  
Great Leap Forward ◽  
Celestial Reference Frame

As discussed in other papers in this volume, the IAU XXIII General Assembly adopted a new fundamental celestial reference frame: the International Celestial Reference Frame (ICRF) based on VLBI observations of extragalactic radio sources (Ma et al., 1997). It is approximately 300 times more accurate than its predecessor, the FK5. At present, no other technique has produced a more accurate celestial frame than VLBI, Since no other astrometric technique provides an external standard of accuracy, the VLBI claim of a great leap forward in accuracy must be verified by internal consistency tests. This paper addresses one aspect of internal consistency: the ability of independent VLBI software packages to reproduce a celestial frame without significant loss of accuracy. This is no small task since the software packages are large - involving on the order of 100 000 lines of code. What does VLBI software do? Aside from routines designed to collect the data and extract raw observables which will not be considered here, its principal task is to model the differential group delay and phase delay rate of radio signals received at two widely separated antennas (Sovers, Fanselow & Jacobs, 1998). The software then refines this model via a least squares adjustment of relevant physical parameters which describe station locations, source positions, clock offsets, atmospheric refraction, tidal effects, etc. In the early 1990s, studies revealed that differences in software implementation and analyst’s choices of model options were one of the largest contributors to differences in independent calculations of VLBI celestial frames. These differences were of comparable size to the formal uncertainties of the celestial frame’s source positions.

The Contribution of LARES to Global Climate Change Studies With Geodetic Satellites

2015 ◽  
Author(s):  
Giampiero Sindoni ◽  
Claudio Paris ◽  
Cristian Vendittozzi ◽  
Erricos C. Pavlis ◽  
Ignazio Ciufolini ◽  
...  
Keyword(s):  
Reference Frame ◽  
Earth Science ◽  
Global Climate ◽  
Temporal Variations ◽  
Terrestrial Reference Frame ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Long Baseline ◽  
Geophysical Processes ◽  
Global Navigation Satellite

Satellite Laser Ranging (SLR) makes an important contribution to Earth science providing the most accurate measurement of the long-wavelength components of Earth’s gravity field, including their temporal variations. Furthermore, SLR data along with those from the other three geometric space techniques, Very Long Baseline Interferometry (VLBI), Global Navigation Satellite Systems (GNSS) and DORIS, generate and maintain the International Terrestrial Reference Frame (ITRF) that is used as a reference by all Earth Observing systems and beyond. As a result we obtain accurate station positions and linear velocities, a manifestation of tectonic plate movements important in earthquake studies and in geophysics in general. The “geodetic” satellites used in SLR are passive spheres characterized by very high density, with little else than gravity perturbing their orbits. As a result they define a very stable reference frame, defining primarily and uniquely the origin of the ITRF, and in equal shares, its scale. The ITRF is indeed used as “the” standard to which we can compare regional, GNSS-derived and alternate frames. The melting of global icecaps, ocean and atmospheric circulation, sea-level change, hydrological and internal Earth-mass redistribution are nowadays monitored using satellites. The observations and products of these missions are geolocated and referenced using the ITRF. This allows scientists to splice together records from various missions sometimes several years apart, to generate useful records for monitoring geophysical processes over several decades. The exchange of angular momentum between the atmosphere and solid Earth for example is measured and can be exploited for monitoring global change. LARES, an Italian Space Agency (ASI) satellite, is the latest geodetic satellite placed in orbit. Its main contribution is in the area of geodesy and the definition of the ITRF in particular and this presentation will discuss the improvements it will make in the aforementioned areas.

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