This paper presents the past,present and future status of the Russian VLBI network "Quasar".This network has been developed for at least 20 years by the Institute of Applied Astronomy of the Russian Academy ...This paper presents the past,present and future status of the Russian VLBI network "Quasar".This network has been developed for at least 20 years by the Institute of Applied Astronomy of the Russian Academy of Sciences(IAA RAS). The equipment installed currently at each "Quasar" station and the facilities for processing observational data are described briefly. The latest results are presented, including the Earth orientation parameters(EOP) determined from the "Quasar" VLBI data and comparison with those from other processing centers. Our future plans to extend the "Quasar" VLB I network to the east and to the west will be carried out by establishing the Ussurijsk station in the Far East and the RussianCuban station in the west. They are considered in the context of the Russian section activity in the GGOS project. The expected improvement of the EOP determination accuracy can be obtained within the future configuration of the "Quasar" network,which is proved by simulation.展开更多
The importance of water vapor in research of global climate change and weather forecast cannot be over emphasized; therefore substantial efforts have been made in exploring the optimal methods to measure water vapor. ...The importance of water vapor in research of global climate change and weather forecast cannot be over emphasized; therefore substantial efforts have been made in exploring the optimal methods to measure water vapor. It is well-established that with a conversion factor, zenith wet delays can be mapped onto precipitable water vapor （PWV）. However, the determination of the exact conversion factor depends heavily on the accurate calculation of a key variable, weighted mean temperature of the trop- osphere （Tin）. AS a critical parameter in Global Positioning System （GPS） meteorology, Tm has recently been modeled into a global grid known as GWMT. The GWMT model only requires the location and the day of year to calculate Tm. Despite the advantages that the GWMT model offers, anomalies still exist in oceanic areas due to low sampling resolution. In this study, we refine the GWMT model by incorporating the global Tm grid from Global Geodetic Observing System （GGOS） and obtain an improved model, GWMT-G. The results indicate that the GWMT-G model successfully addresses the anomaly in oceanic areas in the GWMT model and significantly improves the accuracy of Tm in other regions.展开更多
In this study, a method for determination of stations coordinates, Earth rotation parameters and gravity field coefficients in one solution from SLR data from LAGEOS and LEO is presented. A new software package based ...In this study, a method for determination of stations coordinates, Earth rotation parameters and gravity field coefficients in one solution from SLR data from LAGEOS and LEO is presented. A new software package based on the presented method has been developed. All recommendations from IERS Con- ventions 2010 have been included. In addition, some other perturbations and loading effects are taken into account： atmospheric tides, non-tidal atmosphere and ocean variability, albedo and non-tidal at- mospheric pressure loading. Results of different solutions with the use of only LAGEOS data or LAGEOS plus LEO satellites data are presented. Pole coordinates obtained from both solutions show comparable accuracy relative to IERS 08 C04 solution. As for UT1 corrections in terms of Length-of-Day an additional improvement in accuracy is found： 1.0 ms for LAGEOS and 0.2 ms for the combined LAGEOS ＋ LEO solution. Time series of the estimated degree-2 gravity field coefficients show a very good agreement with results of the Center of Space Research （Austin/USA）. As a final remark, some future mandatory steps are outlined.展开更多
Establishment of the Russian section in the framework of Global Geodetic Observing System （GGOS） is under progress. New components of ＂Quasar＂ network observatories, which are included into GGOS global network as ...Establishment of the Russian section in the framework of Global Geodetic Observing System （GGOS） is under progress. New components of ＂Quasar＂ network observatories, which are included into GGOS global network as core stations, are presented. Recent developments include： two new generation radio telescopes with 13 m antennas at Badary and Zelenchukskaya observatories, water vapor radiometers installed at all observatories and software correlator at the Institute of Applied Astronomy. New and potential developments within other networks belonging to different agencies are also considered in the context of widening of Russian section activity in GGOS project, The paper gives a short overview of status, new components and plans, concerning 5 sub-networks of Federal Agency of Scientific Organi- zations, Roskosmos, Rosstandard, and Rosreestr. Short overview of the plans on creating Data and Analysis Distributed Center is also ~iven.展开更多
文摘This paper presents the past,present and future status of the Russian VLBI network "Quasar".This network has been developed for at least 20 years by the Institute of Applied Astronomy of the Russian Academy of Sciences(IAA RAS). The equipment installed currently at each "Quasar" station and the facilities for processing observational data are described briefly. The latest results are presented, including the Earth orientation parameters(EOP) determined from the "Quasar" VLBI data and comparison with those from other processing centers. Our future plans to extend the "Quasar" VLB I network to the east and to the west will be carried out by establishing the Ussurijsk station in the Far East and the RussianCuban station in the west. They are considered in the context of the Russian section activity in the GGOS project. The expected improvement of the EOP determination accuracy can be obtained within the future configuration of the "Quasar" network,which is proved by simulation.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41174012, 41274022)the National High Technology Research and Development Program of China (Grant No. 2013AA122502)the Open Foundation of Key Laboratory of Precise Engineering and Industry Surveying of National Administration of Surveying, Mapping and Geoinformation (Grant Nos. PF2012-14, PF2013-12)
文摘The importance of water vapor in research of global climate change and weather forecast cannot be over emphasized; therefore substantial efforts have been made in exploring the optimal methods to measure water vapor. It is well-established that with a conversion factor, zenith wet delays can be mapped onto precipitable water vapor （PWV）. However, the determination of the exact conversion factor depends heavily on the accurate calculation of a key variable, weighted mean temperature of the trop- osphere （Tin）. AS a critical parameter in Global Positioning System （GPS） meteorology, Tm has recently been modeled into a global grid known as GWMT. The GWMT model only requires the location and the day of year to calculate Tm. Despite the advantages that the GWMT model offers, anomalies still exist in oceanic areas due to low sampling resolution. In this study, we refine the GWMT model by incorporating the global Tm grid from Global Geodetic Observing System （GGOS） and obtain an improved model, GWMT-G. The results indicate that the GWMT-G model successfully addresses the anomaly in oceanic areas in the GWMT model and significantly improves the accuracy of Tm in other regions.
文摘In this study, a method for determination of stations coordinates, Earth rotation parameters and gravity field coefficients in one solution from SLR data from LAGEOS and LEO is presented. A new software package based on the presented method has been developed. All recommendations from IERS Con- ventions 2010 have been included. In addition, some other perturbations and loading effects are taken into account： atmospheric tides, non-tidal atmosphere and ocean variability, albedo and non-tidal at- mospheric pressure loading. Results of different solutions with the use of only LAGEOS data or LAGEOS plus LEO satellites data are presented. Pole coordinates obtained from both solutions show comparable accuracy relative to IERS 08 C04 solution. As for UT1 corrections in terms of Length-of-Day an additional improvement in accuracy is found： 1.0 ms for LAGEOS and 0.2 ms for the combined LAGEOS ＋ LEO solution. Time series of the estimated degree-2 gravity field coefficients show a very good agreement with results of the Center of Space Research （Austin/USA）. As a final remark, some future mandatory steps are outlined.
文摘Establishment of the Russian section in the framework of Global Geodetic Observing System （GGOS） is under progress. New components of ＂Quasar＂ network observatories, which are included into GGOS global network as core stations, are presented. Recent developments include： two new generation radio telescopes with 13 m antennas at Badary and Zelenchukskaya observatories, water vapor radiometers installed at all observatories and software correlator at the Institute of Applied Astronomy. New and potential developments within other networks belonging to different agencies are also considered in the context of widening of Russian section activity in GGOS project, The paper gives a short overview of status, new components and plans, concerning 5 sub-networks of Federal Agency of Scientific Organi- zations, Roskosmos, Rosstandard, and Rosreestr. Short overview of the plans on creating Data and Analysis Distributed Center is also ~iven.
