Very-Long-Baseline Radio Interferometry: The Mark III System for Geodesy, Astrometry, and Aperture Synthesis

Rogers, A. E. E.; Cappallo, R. J.; Hinteregger, H. F.; Levine, James I.; Nesman, E. F.; Webber, J. C.; Whitney, A. R.; Clark, T. A.; Ma, C.; Ryan, James W.; Corey, B. E.; Counselman, C. C.; Herring, T. A.; Shapiro, I. I.; Knight, C. A.; Shaffer, D. B.; Vandenberg, N. R.; Lacasse, Richard; Mauzy, Robert; Rayhrer, Benno; Schupler, B. R.; Pigg, J.C.

doi:10.1126/science.219.4580.51

Cited by 136 publications

(38 citation statements)

References 10 publications

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“…However, its angular resolution (15 sec × 8.4 degree) is still not enough to identify background counterparts unambiguously. In this condition, VLBI (Very Long Baseline Interferometer, Whitney et al 1976;Rogers et al 1983; Thompson et al 2001) search with even higher angular resolution is very necessary.…”

Section: Introductionmentioning

confidence: 99%

A Fast Radio Burst Search Method for VLBI Observation

Liu¹,

Tong²,

Zheng³

et al. 2018

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We introduce the cross spectrum based FRB (Fast Radio Burst) search method for VLBI observation. This method optimizes the fringe fitting scheme in geodetic VLBI data post processing, which fully utilizes the cross spectrum fringe phase information and therefore maximizes the power of single pulse signals. Working with cross spectrum greatly reduces the effect of radio frequency interference (RFI) compared with using auto spectrum. Single pulse detection confidence increases by cross identifying detections from multiple baselines. By combining the power of multiple baselines, we may improve the detection sensitivity. Our method is similar to that of coherent beam forming, but without the computational expense to form a great number of beams to cover the whole field of view of our telescopes. The data processing pipeline designed for this method is easy to implement and parallelize, which can be deployed in various kinds of VLBI observations. In particular, we point out that VGOS observations are very suitable for FRB search.

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Section: Introductionmentioning

confidence: 99%

A Fast Radio Burst Search Method for VLBI Observation

Liu¹,

Tong²,

Zheng³

et al. 2018

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“…The VLBI technique made a major advance with the introduction of the Mark III VLBI system (Rogers et al 1983, Clark et al 1985. Catalogs using Mark III technology achieved an accuracy of less than 0.5 mas for the best positions (Ma et al 1986, Robertson et al 1986; Mark II measurement by Sovers et al (1988) achieved the same level of accuracy.…”

Section: The Radio Reference Framementioning

confidence: 79%

Reference Frames in Astronomy

Johnston¹,

Vegt²

1999

Annu. Rev. Astron. Astrophys.

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Key Words astrometry, reference frames, reference systems s Abstract Advances in wide-angle astrometric measurements of three to four orders of magnitude in the last thirty years have resulted in a redefinition of the fundamental astronomical reference frame. This new frame, the International Celestial Reference Frame (ICRF), is based on the radio positions of 212 compact extragalactic radio sources. The ICRF defines the direction of the axes of the International Celestial Reference System (ICRS) with a precision of approximately 20 µas. At optical wavelengths, the Hipparcos catalog is the realization of this frame. The precision with which the ICRF is now determined requires that the ICRS models for precession, nutation, and others, be revised. Increases in the precision of measurements from astrometric space missions will further improve the celestial reference frame and may require its redefinition within the next ten years. These improvements will again challenge the models for the celestial reference system.

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“…While collecting more data bits improves the detection signal-to-noise (SN) ratio, the desire to increase the SN ratio must be balanced against the reality of finite recording bandwidths which are 50-100 Mbits/sec for the Mark III VLBI system (Rogers et al, 1983). As a result, the optimal integration times typically range from 2 to 13 minutes.…”

Section: A Experiments Design and Data Collectionmentioning

confidence: 99%

“…Some Ph.D. dissertations of that era are those of Whitney (1974), Robertson (1975), and Ma (1978). After the currently standard Mark III VLBI data acquisition system was developed (Rogers et al, 1983), large-scale international cooperation began in 1979 with the establishment of the Crustal Dynamics Project (CDP) by NASA (Bosworth et al, 1993). In the 1980s, radio interferometry progressed to the point of yielding some of the most accurately measured physical quantities.…”

Section: Introductionmentioning

confidence: 99%

Astrometry and geodesy with radio interferometry: experiments, models, results

1998

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Interferometry at radio frequencies between Earth-based receivers separated by intercontinental distances has made significant contributions to astrometry and geophysics during the past three decades. Analyses of such very long baseline interferometric (VLBI) experiments now permit measurements of relative positions of points on the Earth's surface and of angles between celestial objects at levels of better than one cm and one nanoradian, respectively. The relative angular positions of extragalactic radio sources inferred from this technique presently form the best realization of an inertial reference frame. This review summarizes the current status of radio interferometric measurements for astrometric and geodetic applications. It emphasizes the theoretical models that are required to extract results from the VLBI observables at present accuracy levels. An unusually broad cross section of physics contributes to the required modeling. Both special and general relativity need to be considered in properly formulating the geometric part of the propagation delay. While high-altitude atmospheric charged-particle (ionospheric) effects are easily calibrated for measurements employing two well-separated frequencies, the contribution of the neutral atmosphere at lower altitudes is more difficult to remove. In fact, mismodeling of the troposphere remains the dominant error source. Plate tectonic motions of the observing stations need to be taken into account, as well as the nonpointlike intensity distributions of many sources. Numerous small periodic and quasiperiodic tidal effects also make important contributions to space geodetic observables at the centimeter level, and some of these are just beginning to be characterized. Another area of current rapid advances is the specification of the orientation of the Earth's spin axis in inertial space: nutation and precession. Highlights of the achievements of very long baseline interferometry are presented in four areas: reference frames, Earth orientation, atmospheric effects on microwave propagation, and relativity. The order-of-magnitude improvement of accuracy that was achieved during the last decade has provided essential input to geophysical models of the Earth's internal structure. Most aspects of VLBI modeling are also directly applicable to interpretation of other space geodetic measurements, such as active and passive ranging to Earth-orbiting satellites, interplanetary spacecraft, and the Moon. [S0034-6861(98)

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Very-Long-Baseline Radio Interferometry: The Mark III System for Geodesy, Astrometry, and Aperture Synthesis

Cited by 136 publications

References 10 publications

A Fast Radio Burst Search Method for VLBI Observation

A Fast Radio Burst Search Method for VLBI Observation

Reference Frames in Astronomy

Astrometry and geodesy with radio interferometry: experiments, models, results

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