The Chinese VLBI network and its astrometric role

Li, J. L.; Guo, Lei; Zhang, B.

doi:10.1017/s174392130801898x

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…And such precise parameters allow us to probe the physics of neutron star formation in supernova, as well as the intervening interstellar medium and so on; Combined with the timing measurement, we can also research on the topic of the reference frames tie. Besides, with the astrometric and geodetic observations, CVN can regularly conduct the EOP determination and also monitor the baseline length [17]. …”

Section: Resultsmentioning

confidence: 99%

New determination of the position of the pulsar B0329+54 with Chinese VLBI network

Guo

Zheng

Zhang

et al. 2010

Sci. China Phys. Mech. Astron.

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We present the first successful CVN (Chinese VLBI Network) phase-referencing observation of the pulsar B0329+54 on October 16, 2008 in S band. A new background source, J0347+5557, 2.5 • away from the pulsar was employed as a position reference, which is closer to the pulsar and better for the 'nodding' mode than that used in previous observations. The position by fitting image of the pulsar relative to the calibrator is accurately determined at the level of tens of μas, which is comparable with the present differential VLBI astrometric accuracy, proving that CVN will be a potential powerful tool for astrometry and astrophysics. PSR B0329+54, VLBI, CVN, phase reference PACS: 95.75Kk, 95.85Bh Proper motion and trigonometric parallax of pulsars can be obtained with Very Long Baseline Interferometry (VLBI) phase-referencing observations. These parameters through such observations can provide the only model-independent distances and velocities of pulsars and also can be exploited to address a variety of scientific questions such as making associations with Supernova Remnants, improving the accuracy of kinematic and distance information for use in timing, luminosity, and Galactic electron distribution models, making reference frame ties, pulsar auto-navigation techniques and so on [1][2][3].PSR B0329+54 with the period of 0.7 s is one of the strongest pulsars in the sky. So it has been extensively studied on the proper motion, distance and interstellar scintillation by single dish, and VLBI by many authors [4][5][6][7]. Though severely punishing observations were made at higher frequencies [5], observations of the pulsar are always set in lower frequencies (including L band) due to weak flux and its steep power-law spectra. Since 2000 January, the timing observations of PSR B0329+54 have been carried out by *Corresponding author (email: kent-gl@shao.ac.cn) using Nanshan 25-m radio telescope at the frequency of 1540 MHz with two polarizations fed to a filter-bank consisting of 2×128 contiguous channels and each of the width 2.5 MHz [8]. The timing position published by using the Nanshan data from 2000 January to 2004 August is α(J2000.0) = 03 h 32 m 59 s .391(7) and δ(J2000.0) = 54 • 34 43 .40(8) at epoch MJD 52337.0 [8]. Brisken et al. measured the parallax and proper motion of the pulsar B0329+54 using Very Long Baseline Array (VLBA). The parallax was 0.94 ± 0.11 mas and the proper motions were μ α = 17.0 ± 0.27 mas yr −1 and μ δ = −9.48 ± 0.37 mas yr −1 , respectively. Positions of the pulsar were α(J2000.0) = 03 h 32 m 59 s .3862 and δ(J2000.0) = 54 • 34 43 .5051 calibrated with J0302+5331, 4 • .37 away [5]from the pulsar. The VLBA Observations were set in L band, and antennas nodded back and forth between the pulsar and the calibrator with a cycle time of 5 min. And the 338 MHz wide band available from VLBA receivers was Nyquist sampled in eight 8 MHz spectral windows ranging from 1410 to 1730 MHz. Pulsar gating employed in the correlator is an important technique in such observations, which increases sensiti...

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Section: Resultsmentioning

confidence: 99%

New determination of the position of the pulsar B0329+54 with Chinese VLBI network

Guo

Zheng

Zhang

et al. 2010

Sci. China Phys. Mech. Astron.

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“…The quality of the tracking data can be real-timely monitored and the trajectory can be measured rapidly and geometrically by positioning analysis. Especially during orbital maneuver, soft-landing and surface walking, because it is not easy to model precisely the forces exerted on probes, the positioning analysis can be used for rapid trace measurement [8][9][10][11].…”

Section: The Determination Of the Landing Trajectory Of Ce-satellite mentioning

confidence: 99%

Determination of the controlled landing trajectory of Chang’E-1 satellite and the coordinate analysis of the landing point on the Moon

Guo

Qian

et al. 2010

Chin. Sci. Bull.

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Based on the tracking observations of radio ranges and VLBI delays of Chang'E-1 (CE-1) satellite during the controlled landing on the Moon on March 1, 2009, the landing trajectory and the coordinates of the landing point are determined by positioning analysis. It is shown that the landing epoch (the emission epoch of the last signal) of CE-1 satellite on the Moon was at UTC8h13m6.51s. The lunar longitude, latitude and surface height of the landing point in the lunar primary axes frame are respectively 52.2732°, 1.6440° and -3.56 km (the reference lunar radius is 1738 km). The uncertainties are 0.0040°, 0.0168° and 0.18 km. The corresponding uncertainty in the tangential direction of the lunar surface is 0.52 km and the three-dimensional (3D) positioning uncertainty is 0.55 km. It is accordingly deduced that even with the present technical specifications of the radio ranges and VLBI delays, the 1 km 3D positioning precision could be guaranteed for the lander in the second stage of China's Lunar Exploration Project. Concerning the trace determination of the rover on the lunar surface, because only telemetry signal will be emitted, VLBI would be the sole tracking technique from the Earth. The application of the constraint of geocentric distance is shown to be helpful to improving the positioning precision. It is worthy to pay close attention to the applications of the same beam VLBI technique, the lunar topographic model and the on-board observations of the lander and rover to the position/trace determination of the rover. China's Lunar ExplorationProject, Chang'E-1 satellite, controlled landing on the Moon, trajectory measurement, VLBI Citation: Li J L, Guo L, Qian Z H, et al. Determination of the controlled landing trajectory of Chang'E-1 satellite and the coordinate analysis of the landing point on the Moon.

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Orbit determination for a space-based gravitational wave observatory

Zheng

2021

Acta Astronautica

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The Chinese VLBI network and its astrometric role

Cited by 5 publications

References 3 publications

New determination of the position of the pulsar B0329+54 with Chinese VLBI network

New determination of the position of the pulsar B0329+54 with Chinese VLBI network

Determination of the controlled landing trajectory of Chang’E-1 satellite and the coordinate analysis of the landing point on the Moon

Orbit determination for a space-based gravitational wave observatory

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