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The Space VLBI mission, VSOP, involves the participation of 15 countries with up to 40 radio telescopes spread across the Earth observing in close coordination with the 8 m radio telescope on board the Japanese spacecraft HALCA (Hirabayashi, 1998, and this Proceedings). This paper describes the contributions to the mission's success from Southern Hemisphere radio telescopes, facilities and Institutes.

The Jet Propulsion Laboratory (JPL) is a participant in the VSOP Space VLBI mission, an extensive international collaboration led by Japan's Institute of Space and Astronautical Science (ISAS). The JPL effort is funded by the U.S. National Aeronautics and Space Administration (NASA). To obtain data from the orbital element of the VSOP mission, the Japanese HALCA satellite, the Deep Space Network (DSN) of JPL has built a new set of three 11-meter tracking stations in California, Spain, and Australia. These stations have supported over 1000 HALCA passes during the first year of operation, and supply science, telemetry, and Doppler data for the mission. JPL is using the Doppler data to estimate the satellite orbital parameters that are needed by the tracking stations and VLBI data correlators. The DSN also modified their three 70-meter antennas to provide ground VLBI observing support for the mission. In addition to operational support, JPL has had significant involvement in the mission planning and scientific support aspects of the mission, including mission design, international data flow, scientific scheduling, and data analysis during in-orbit checkout. JPL has also aided the scientific community in the use of VSOP by developing a user software package, writing a guide for proposers, and establishing a proposer help desk.

The Russian Academy of Sciences and Federal Space Agency, together with the participation of many international organizations, worked toward the launch of the RadioAstron orbiting space observatory with its onboard 10-m reflector radio telescope from the Baikonur cosmodrome on July 18, 2011. Together with some of the largest ground-based radio telescopes and a set of stations for tracking, collecting, and reducing the data obtained, this space radio telescope forms a multi-antenna ground-space radio interferometer with extremely long baselines, making it possible for the first time to study various objects in the Universe with angular resolutions a million times better than is possible with the human eye. The project is targeted at systematic studies of compact radio-emitting sources and their dynamics. Objects to be studied include supermassive black holes, accretion disks, and relativistic jets in active galactic nuclei, stellar-mass black holes, neutron stars and hypothetical quark stars, regions of formation of stars and planetary systems in our and other galaxies, interplanetary and interstellar plasma, and the gravitational field of the Earth. The results of ground-based and inflight tests of the space radio telescope carried out in both autonomous and ground-space interferometric regimes are reported. The derived characteristics are in agreement with the main requirements of the project. The astrophysical science program has begun., 54 pages, 11 figures; published by Astronomicheskij Zhurnal (in Russian) and Astronomy Reports (in English)

Mobile broadcast digital TV represents the latest grand addition to the mobile handset convergence phenomenon. Even before it began, mobile DTV was likened to the next killer application in the handset – analogous to the camera phone – and it understandably receives great attention with the annual handset market size rapidly approaching the billion unit mark. Arguably, much of this appeal stems from the opportunities for so many players in an expanded value web, especially involving the entrance of the broadcast and entertainment community's content, aggregation, and distribution providers into the conventional mix of the cellular communications community's technology, system, and handset providers, and network operators. In this paper, we present an overview of the mobile DTV landscape. We also focus on the architectures for mobile DTV within the cellular handset from the systems perspective, with emphasis on the architectural implications for the handset designer and across market segmentations from the higher-end multimedia phones to the mid- and lower-range feature phones where many believe mobile DTV will ultimately shine as does the camera today.

High angular resolution images of extragalactic radio sources are being made with the Highly Advanced Laboratory for Communications and Astronomy (HALCA) satellite and ground-based radio telescopes as part of the Very Long Baseline Interferometry (VLBI) Space Observatory Programme (VSOP). VSOP observations at 1.6 and 5 gigahertz of the milli–arc-second–scale structure of radio quasars enable the quasar core size and the corresponding brightness temperature to be determined, and they enable the motions of jet components that are close to the core to be studied. Here, VSOP images of the gamma-ray source 1156+295, the quasar 1548+056, the ultraluminous quasar 0014+813, and the superluminal quasar 0212+735 are presented and discussed.

We describe a space VLBI experiment involving an earth-orbiting satellite (SURFSAT) and simulated satellites, a space VLBI ground tracking station, an array of ground radio telescopes, and a space VLBI correlator. The purpose of this experiment was to provide as complete as possible an end-to-end simulation of space VLBI in preparation for the first space VLBI mission, VSOP, and in particular to test the most critical aspect of space VLBI, viz. the ability to generate a stable and accurate frequency standard (clock) for the orbiting VLBI element.

The phase-coherent recording of pulsar data and subsequent software dispersion removal provide a flexible way to reach the limits of high time resolution, useful for more precise pulse timing and the study of fast signal fluctuations within a pulse. Because of the huge data rate and lack of adequate recording and computing capabilities, this technique has been used mostly only for small pulsar data sets. In recent years, however, the development of very capable, reasonably inexpensive high-speed recording systems and computers has made feasible the notion of pulsar baseband recording and subsequent processing with a workstation/computer. In this paper we discuss the development of a phase-coherent baseband processing system for radio pulsar observations. This system is based on the S2 VLBI recorder developed at ISTS/York University in Toronto, Canada. We present preliminary first results for data from the Vela pulsar, obtained at Parkes, Australia, and processed at ISTS/York University, and discuss plans for future developments.

The site distribution of the different charge compensated sites in singly doped samples of SrCl2:Eu3+ and doubly doped samples containing a second rare earth ion has been measured by site selective laser spectroscopy for a range of different dopant concentrations and annealing temperatures. The site distribution exhibits the same anomalous behavior as was observed in alkaline earth halide crystals as long as the dopant levels are not too low. At very low dopant levels, the anomalous behavior is not observed and the dependence follows that expected for simple mass action descriptions of defect equilibria. An association constant is obtained at the low concentrations and it is found that the amount of association is much less than would be expected from theoretical estimates based on Harwell automatic defect evaluation system (HADES) models. Extensive clustering is observed at lower concentrations than in the alkaline earth fluorides. The number of different clusters and the types of clusters do not appear ...

Site selective spectroscopy has been performed for SrCl2:Eu3+ samples. The Eu3+ lines have been classified into nine major sites. The anomalous behavior of these sites as a function of concentration and annealing temperature is similar to that of rare earth doped CaF2, except that clusters are more stable in SrCl2. These results for SrCl2, a material which has the fluorite structure but no fluoride, eliminate the possibility that the anomalous behavior in the fluorites is due to fluoride.

Site selective spectroscopy has been performed for CaF2:Eu3+ samples as a function of annealing temperature and dopant concentration. The Eu3+ lines have been classified into five sites, two of which correspond with Eu3+ clusters. High annealing temperatures dissociate the clusters and leave Eu3+ ions in cubic and tetragonal sites. The relative concentrations of these sites change anomalously as the Eu3+ concentration is raised. Absolute concentration measurements of all the sites eliminates competing equilibria as a possible explanation. These results confirm the conclusions reached in an earlier paper for a more complex system.

Site selection excitation has been used to classify the sites in .01 % to .3 % concentrations of SrCl2:Eu3+ into cubic, associated single ions, and clusters. Site dependence on total dopant concentration has been measured and is similar to other fluorite crystals.

The S2 baseband processing system (S2-BPS) is designed for a variety of pulsar measurements such as ultrafast signal fluctuations and pulse timing. Its key features are: the S2 recorder; the S2 Tape-to-Computer Interface (S2-TCI) which provides an efficient high data rate transfer from S2 tapes to computer; and the tightly coupled control interface to the computer which enables automated data transfer and processing. Developed originally for VLBI applications, the S2 recorder is based on the use of commercial VHS tape transports (VCR's), modified for use in digital high density, high data rate applications. A single S2 recorder "tape-set" of eight SVHS tapes provides up to 500 GBytes of data storage, and an unattended operating time of up to 8.5 hours at the maximum data rate of 128 Mbits/s or 16 MBytes/s, corresponding typically to 16 MHz bandwidth in two circular polarizations at 2-bit quantization, which generates a data rate of up to 1 GByte/minute. With 16 MHz individual record channels, a single S2 yields a sample time resolution of 31 ns. For more challenging applications, multiple S2's may be used for increased bandwidth and higher time resolutions. In this paper, we present an overview of the S2 baseband processing system and plans for future implementations of the system, and demonstrate first results of Vela pulsar recordings at Parkes in September 1995. We pay specific attention to the S2-TCI, a system designed to transfer S2 recorded data from tape to computer memory (RAM) via direct memory access (DMA). Computer data may be processed locally or sent to a more powerful "remote" (super) computer for processing.