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From 43GHz VLBA observations of the pair of radio sources 1928+738 and 2007+777 we have demonstrated the feasibility of precision phase-delay differential astrometric techniques at millimeter wavelengths. For a pair of sources with 5…

天体物理学 · 物理学 2007-05-23 J. C. Guirado , J. M. Marcaide , M. A. Perez-Torres , E. Ros

Flight height is a fundamental parameter for correcting the gamma signal produced by terrestrial radionuclides measured during airborne surveys. The frontiers of radiometric measurements with UAV require light and accurate altimeters flying…

This letter provides a comparison of indoor radio propagation measurements and corresponding channel statistics at 28, 73, and 140 GHz, based on extensive measurements from 2014-2020 in an indoor office environment. Side-by-side comparisons…

信息论 · 计算机科学 2021-10-26 Yunchou Xing , Theodore S. Rappaport , Amitava Ghosh

Using the international ground-based network of two-frequency receivers of the GPS navigation system provides a means of carrying out a global, continuous and fully-computerized monitoring of phase fluctuations of signals from…

地球物理 · 物理学 2007-05-23 E. L. Afraimovich , V. A. Karachenschev

In a radio interferometer, the determination of geometrical antenna positions relies on accurate calibration of the dry and wet delay of the atmosphere above each antenna. For the Atacama Large Millimeter/Submillimeter Array (ALMA), which…

We obtained laboratory spectra of absorption by water vapor at the wavelengths 6500-10500 {\AA} with the multipass cell. The water vapor content along the line of view varied from 0.1 to 3.0 cm of precipitated water, the pressure from 0.1…

天体物理仪器与方法 · 物理学 2010-10-26 G. A. Alekseeva , V. D. Galkin , I. B. Sal'nikov

We developed a radio interferometric technique for the observation of extensive air showers initiated by cosmic particles. In this proof-of-principle study we show that properties of extensive air showers can be derived with high accuracy…

高能天体物理现象 · 物理学 2022-01-11 Harm Schoorlemmer , Washington R. Carvalho

Empirical path loss models are defined for a specific antenna system used during measurements and characterized by a particular radiation pattern and main lobe beam width. In this paper, we propose a novel approach to modifying such a model…

Propagation channel characteristics are substantially different in sub-6 GHz and millimeter-wave (mmWave) bands. A typical mmWave link experiences more than an order-of-magnitude larger path loss and is more susceptible to blockages than a…

信号处理 · 电气工程与系统科学 2020-02-04 Ozgur Ozdemir , Fatih Erden , Ismail Guvenc , Taha Yekan , Tom Zarian

We describe and demonstrate a technique for correcting direction dependent artifacts due to asymmetries in antenna patterns and differences among antennas used in radio interoferometric imaging. The technique can correct images in all…

天体物理仪器与方法 · 物理学 2021-10-13 W. D. Cotton , T. Mauch

An accurate estimate of the inner edge of the habitable zone is critical for determining which exoplanets are potentially habitable and for designing future telescopes to observe them. Here, we explore differences in estimating the inner…

We present a millimetre-wave site characterisation for the Australia Telescope Compact Array (ATCA) based on nearly 9 years of data from a seeing monitor operating at this facility. The seeing monitor, which measures the phase fluctuations…

天体物理仪器与方法 · 物理学 2015-06-19 Balthasar T. Indermuehle , Michael G. Burton

Interferometric measurements of the radio emission of extensive air showers allow reconstructing cosmic-ray properties. A recent simulation study with an idealised detector promised measurements of the depth of the shower maximum…

天体物理仪器与方法 · 物理学 2022-12-16 Felix Schlüter , Tim Huege

The ngVLA has adopted a standalone system with a $\sim$~1.5 m diameter antenna and associated ambient temperature receiver and electronics at each antenna as its baseline design for water vapor radiometer (WVR). The WVR is intended to…

天体物理仪器与方法 · 物理学 2026-02-24 Tirupati Kumara Sridharan , Robert Lehmensiek , Yoshiharu Asaki

Pulsar radio emission undergoes dispersion due to the presence of free electrons in the interstellar medium (ISM). The dispersive delay in the arrival time of pulsar signal changes over time due to the varying ISM electron column density…

Path loss is a significant component of wireless communication channel design and analysis and reflects the reduction in a transmitted signal's power density. Due to the differences in the propagation conditions, wireless aerial channels'…

信息论 · 计算机科学 2021-01-29 Hazim Shakhatreh , Waed Malkawi , Ahmad Sawalmeh , Muhannad Almutiry , Ali Alenezi

We have used the Submillimeter Wave Astronomy Satellite to map the ground-state 1_{10}-1_{01} transition of ortho-water at 557 GHz in the Orion molecular cloud. Water emission was detected in Orion over an angular extent of about 20 arcmin,…

Extending geodetic and astrometric Very Long Baseline Interferometry (VLBI) observations from traditional centimeter wavebands to millimeter wavebands offers numerous scientific potentials and benefits. However, it was considered quite…

The propagation of Langmuir waves in plasmas is known to be sensitive to density fluctuations. Such fluctuations may lead to the coexistence of wave pairs that have almost opposite wave-numbers in the vicinity of their reflection points.…

空间物理 · 物理学 2011-07-25 V. V. Krasnoselskikh , T. Dudok de Wit , S. D. Bale

Millimeter wave is a promising technology for the next generation of wireless systems. As it is well-known for its high path loss, the systems working in this spectrum tend to exploit the shorter wavelength to equip the transceivers with a…

信息论 · 计算机科学 2018-01-12 Sina Shaham , Matthew Kokshoorn , Zihuai Lin , Ming Ding