This article describes currently used analysis strategy and data analysis software for geodetic VLBI. Today’s geodetic observing strategies are shortly presented, and the geodetic VLBI observables and data modeling are briefly discussed. A short overview is given on existing geodetic VLBI software packages and the statistical approaches that are applied. Necessary improvements of today’s analys...

The history of VLBI is summarized with emphasis on the technical aspects. A summary of VLBI systems which are in use is given, and an outlook to the future of VLBI instrumentation.

Circumstellar masers are unique tools for probing the envelopes around low mass dying stars using VLBI. In this contribution I briefly review the status of our knowledge on these emissions, especially focusing on the latest results obtained by means of VLBI observations. I also outline some of the new windows that will open for VLBI maser research thanks to the upcoming new instrumentation.

We have conducted a deep, very long baseline interferometry (VLBI) observation at 1.4 GHz of an area of sky located within the NOAO Boötes field, using the NRAO Very Long Baseline Array and 100-m Green Bank Telescope. Applying wide-field VLBI techniques, a total of 61 sources, selected from a Westerbork Synthesis Radio Telescope (WSRT) image, were surveyed simultaneously with a range of differe...

Millimeter-VLBI images probe as deep as never before the nuclei of AGN. VLBI at 147GHz yields transatlantic fringes for the first time. Now we can begin to study the relation between jet kinematics and spectral activity with a few ten micro-arcsecond resolution. 1. Present Status of 3mm-VLBI The main advantage of VLBI observations at short millimeter wavelengths (mmVLBI) is the very high angula...

The quasar 3C 345 is one of the best examples of extra-galactic jet with superluminal components moving on helical paths. To get better constraints on the jet physics, we have imaged the source at the highest possible resolution, using mm-VLBI and space-VLBI observations. We observed 3C 345 at 5 different epochs so far (1 epoch with 3-mm ground VLBI, and 4 epochs with space VLBI at 6 cm and 18 ...

The International VLBI Service for Geodesy and Astrometry (IVS) is a globally operating service that coordinates and performs Very Long Baseline Interferometry (VLBI) activities through its constituent components. The VLBI activities are associated with the creation, provision, dissemination, and archiving of relevant VLBI data and products. The data and products are stored in dedicated IVS com...

Imaging the vicinity of a black hole is one of the ultimate goals of VLBI astronomy The closest massive black hole SgrA located at the Galactic center is the leading candidate for such observations Combined with recent VLBI recording technique and submillimeter radio engineering we now have the su cient sensitivity for the observations Here we show performance simulations of submillimeter VLBI ...

In this paper I outline a new strategy for the routine detection and imaging of faint (sub-mJy and microJy) radio sources with VLBI and SVLBI. The strategy relies on a combination of in-beam phase-referencing, wide-field VLBI imaging and simultaneous correlation of multiple field centres. A combination of these techniques, together with the steeply rising radio source counts observed at cm wave...

The Global mm–VLBI Array is at present the most sensitive 3mm–VLBI interferometer and provides images of up to 40 micro–arcsecond resolution. Using this array, we have monitored the rotation of the innermost jet in the quasar NRAO150, which shows an angular speed of ∼ 7◦/yr. Future 3mm arrays could include additional stations like ALMA, GBT, LMT, CARMA, SRT, Yebes, Nobeyama and Noto, which woul...