scholarly journals The NAVOBSY/NRL Program for the Determination of Earth Rotation and Polar Motion

1979 ◽  
Vol 82 ◽  
pp. 211-215
Author(s):  
K. J. Johnston ◽  
J. H. Spencer ◽  
C. H. Mayer ◽  
W. J. Klepczynski ◽  
G. Kaplan ◽  
...  
Keyword(s):  
Earth Rotation ◽  
Polar Motion ◽  
The United States ◽  
Precise Determination ◽  
Naval Research ◽  
Radio Sources ◽  
Naval Observatory ◽  
Earth Rotation Parameters ◽  
Rotation Parameters

The joint program of NAVOBSY/NRL is discussed.The United States Naval Observatory (NAVOBSY) and the Naval Research Laboratory (NRL) are collaborating in a program to apply radio interferometric techniques to the determination of variations in Earth rotation, polar motion, and improved astronomical position reference systems. Investigations of VLBI and connected interferometer techniques and radio sources for astrometic application have been in progress for several years as part of the NRL radio astronomy program, and currently NRL and NAVOBSY are carrying out experimental programs to investigate VLBI time transfer techniques and UT determination using the connected element interferometer of the NRAO in Green Bank. Some previous results of observations using the Green Bank interferometer and proposed plans for operation as a dedicated system over a period of time to evaluate effectiveness for precise determination of Earth rotation parameters are discussed.

scholarly journals Stability of Determining the Earth Rotation Parameters (ERP) with VLBI

1988 ◽  
Vol 129 ◽  
pp. 417-420
Author(s):  
Shifang Luo ◽  
Dawei Zheng
Keyword(s):  
Earth Rotation ◽  
Polar Motion ◽  
Systematic Errors ◽  
Geometric Effect ◽  
The Earth ◽  
Geometric Uncertainty ◽  
Earth Rotation Parameters ◽  
Rotation Parameters ◽  
The Stability

By using the observations of IRIS network, the stability of determinang ERP with VLBI is studied. It is concluded that the uncertainties from initial values of ERP, the errors of other parameters are at the same level as the formal errors in determination of ERP. The geometric effect on determination of ERP is important and appears as systematic errors. Geometric uncertainty on polar motion is greater than that on UT1. and specially much worse for the continenal network. The stability of determining ERP with VLBI can be improved either by increasing new stations at reasonable location in a VLBI network or by increasing new networks.

scholarly journals SLR Contribution to Investigation of Polar Motion

2000 ◽  
Vol 178 ◽  
pp. 267-276
Author(s):  
Zinovy Malkin
Keyword(s):  
Earth Rotation ◽  
Polar Motion ◽  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
International Earth Rotation Service ◽  
Global Tracking ◽  
International Earth Rotation ◽  
Earth Rotation Parameters ◽  
Rotation Parameters

AbstractThe Satellite Laser Ranging (SLR) technique has been used to determine Earth Rotation Parameters (ERP) for over twenty years. Most of results contributed to the International Earth Rotation Service (IERS) are based on analysis of observations of Lageos 1 & 2 satellites collected by the global tracking network of about 40 stations. Now five analysis centers submit operational (with 2–15 days delay) solutions and about ten analysis centers contribute yearly final (up to 23 years) ERP series. Some statistics related to SLR observations and analysis are presented and analyzed. Possible problems in SLR observations and analysis and ways of its solution are discussed.

scholarly journals The Background to the Merit/Cotes Recommendations on the Terrestrial and Celestial Reference Systems

1986 ◽  
Vol 7 ◽  
pp. 81-84
Author(s):  
G A Wilkins
Keyword(s):  
International Collaboration ◽  
Earth Rotation ◽  
Reference Frames ◽  
Radio Sources ◽  
Reference Systems ◽  
International Earth Rotation Service ◽  
Earth Rotation Parameters ◽  
Working Groups ◽  
Rotation Parameters ◽  
Better Than

AbstractThe MERIT programme of international collaboration to monitor earth-rotation and to intercompare the techniques of observation and analysis has fostered the development of the use of space techniques. Earth-rotation parameters are now determined regularly with a precision that is better than 1 milliarcsecond () and the relative positions of the observing stations are determined to better than 1 decimetre (0.1 m). It is therefore necessary that the terrestrial and celestial reference frames be defined more precisely. The MERIT and COTES Working Groups have proposed that new conventional terrestrial and celestial reference systems be established and that the maintenance of these systems be the responsibility of a new International Earth Rotation Service. The new reference frames are to be based on the adoption of positions and motions of designated stations and extragalactic radio sources. Appropriate models and parameters will be associated with these frames to form reference systems so that observations can be used to determine the rotation of the terrestrial frame with respect to the celestial frame.

The International DORIS Service is preparing the future

2020 ◽  
Author(s):  
Pascale Ferrage ◽  
Laurent Soudarin ◽  
Frank Lemoine
Keyword(s):  
Earth Rotation ◽  
International Association ◽  
Tracking System ◽  
Tectonic Plate ◽  
Plate Motions ◽  
The Earth ◽  
Earth Rotation Parameters ◽  
The Future ◽  
Rotation Parameters

<p>The DORIS system recorded its first measurement on February 3rd, 1990, from the SPOT-2 remote sensing satellite. 30 years after, the system is at its best. DORIS has proven greatly valuable for geodesy and geophysics applications: measuring tectonic plate motions, determination of the rotation and the gravity parameters of the Earth, contributing to the international reference system. Technological and methodological improvements have allowed the improvement in the estimates of the positions of the DORIS tracking ground stations, the Earth rotation parameters and other geodetic variables such as the geocenter and the scale of the ITRF.<br>The International DORIS Service (IDS) was created in 2003 under the umbrella of the International Association of Geodesy (IAG) to foster scientific research related to the French DORIS tracking system and to deliver scientific products, mostly related to the International Earth rotation and Reference systems Service (IERS). Since its start, the organization has continuously evolved, leading to additional and improved operational products from an expanded set of DORIS Analysis Centers. IDS is now based on a reinforced structure with two Data Centers, six Analysis Centers, four Associate Analysis Centers, and a Combination Center. Using the experience gained in the preparation of the ITRFs, many improvements were made all along both in data analysis and on technical aspects. After the IDS Retreat held in June 2018, the IDS GB worked on the development of a strategic plan for the IDS. In the coming years, IDS will focus on growing the community, extending the DORIS applications, and improving the technology, the infrastructure and the processing.<br>This presentation addresses the recent achievements made by IDS and how the service is preparing the future.</p>

scholarly journals Is Lunar Ranging a Viable Component in a Next-Generation Earth Rotation Service?

1979 ◽  
Vol 82 ◽  
pp. 257-260 ◽  
Author(s):  
J. Derral Mulholland
Keyword(s):  
Earth Rotation ◽  
Laser Ranging ◽  
Next Generation ◽  
Lunar Laser Ranging ◽  
New Techniques ◽  
Lunar Laser ◽  
Earth Rotation Parameters ◽  
New Space ◽  
Rotation Parameters

Several new “space” techniques have been used for episodic determination of Earth rotation parameters, usually the variation in apparent longitude (UT0) and apparent latitude of an observing station. Earth rotation services require more than episodic determinations; they need near-daily determinations. Since 1975, planning has been underway for a demonstration of the viability of lunar laser ranging for such a usage. The observing campaign named Earth Rotation from Lunar Distances (EROLD) was organized with the proposed activity to cover the years 1977–78. Progress has not been so rapid as hoped, but it remains true that lunar ranging has produced more Earth rotation information than other new techniques.

Combination of GNSS and VLBI data for consistent estimation of Earth Rotation Parameters

2021 ◽  
Author(s):  
Lisa Lengert ◽  
Claudia Flohrer ◽  
Anastasiia Girdiuk ◽  
Hendrik Hellmers ◽  
Daniela Thaller
Keyword(s):  
Time Series ◽  
Earth Rotation ◽  
Polar Motion ◽  
Normal Equation ◽  
Station Coordinates ◽  
Earth Rotation Parameters ◽  
Vlbi Data ◽  
Rotation Parameters ◽  
Gnss Data ◽  
The Impact

<p>We present the current activities of the Federal Agency for Cartography and Geodesy (BKG) towards a combined processing of VLBI and GNSS data.  The main goal of the combined analyses of the two different space-geodetic techniques is the improvement of the consistency between the techniques through common parameters, i.e., mainly Earth Rotation Parameters (ERPs), but also station coordinates and tropospheric parameters through local ties and atmospheric ties, respectively.</p><p>Based on our previous combination studies using GNSS data and VLBI Intensive sessions on a daily and multi-day level, we generate a consistent, low-latency ERP time series with a regular daily resolution for polar motion and dUT1. We achieved in this way a significant accuracy improvement of the dUT1 time series and a slight improvement of the pole coordinates time series, comparing ERPs from the combined processing with the individual technique-specific ERPs.</p><p>In our recent studies, we extend the combination of GNSS and VLBI Intensive sessions by adding VLBI 24-hour sessions in order to exploit the benefit of the combination to its maximum extend. We analyse the impact of the combination on the global parameters of interest, i.e., mainly dUT1, polar motion and LOD, but also on station coordinates.</p><p>BKG’s primary interest is the combination of GNSS and VLBI data on the observation level. However, the current combination efforts are based on the normal equation level using technique-specific SINEX files as a starting point.</p>

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