نتایج جستجو برای: line of sight

تعداد نتایج: 21192216  

Journal: :Proceedings of the International Astronomical Union 2004

Journal: :IEEE Transactions on Wireless Communications 2021

This paper establishes an upper bound on the capacity of line-of-sight multiantenna channels over all possible antenna arrangements and shows that uniform linear arrays (ULAs) with SNR-dependent rotation transmitter and/or receiver can closely approach such capacity-and in fact achieve it at low high SNR, asymptotically numbers antennas. Then, as alternative to mechanically rotating ULAs, we pr...

Journal: :Journal of Cosmology and Astroparticle Physics 2021

While most strong-gravitational-lensing systems may be roughly modelled by a single massive object between the source and observer, in details all structures near light path contribute to observed images. These additional contributions, known as line-of-sight effects, are non-negligible practice. This article proposes new theoretical framework model together with very promising applications at ...

2014
Min-Guk Seo Min-Jea Tahk Chang-Kyung Ryoo

The observability of radome aberration estimation with line-of-sight (LOS) angle-only measurement is studied in this paper. When missile seeker can only measure LOS angle of target, target state variables are required to be estimated with this measurement for accurate missile guidance. Since LOS angle measurement contains error, caused by radome attached at missile nose and called radome aberra...

2005
Andreas Burkert Thorsten Naab

The projected kinematical properties of unequal-mass merger remnants of disk galaxies are analysed and shown to agree well with observations of disky, fast rotating elliptical galaxies. This supports the major merger hypothesis of early-type galaxy formation. However, in contrast to previous claims, the merger remnants are very anisotropic with values of the anisotropy parameter that are simila...

2009
Li Huang Ruben de Francisco Guido Dolmans

In order to facilitate the deployment of wireless systems in medical environments, channel measurements at 2.4GHz band have been performed in a hospital bedroom. Based on measurements in different line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios, we determine the large-scale path loss and different small-scale fading parameters. Applying the channel models in our MATLAB simulation env...

2013
Anastasios M. Lekkas Thor I. Fossen

This paper presents an overview of the Line-of-Sight (LOS) guidance law, which is a widely used method for generating heading reference trajectories, for path-following applications of marine vehicles. Due to the fact that these reference trajectories depend also on the form of the path, five path evaluation criteria are discussed. The guidance problem is presented in a constructive manner. Fir...

1998
Martin Elvis Fabrizio Fiore Paolo Giommi Paolo Padovani

We have selected quasars with X-ray colors suggestive of a low energy cutoff, from the ROSAT PSPC pointed archive. We examine the radio and optical properties of these 13 quasars. Five out of the seven quasars with good optical spectra show associated optical absorption lines, with two having high ∆v candidate systems. Two other cut-off quasars show reddening associated with the quasar. We conc...

2008
H. Men J. L. Han

Aims. Our purpose is to place firm observational constraints on the three most widely used theoretical models for the spatial configuration of the large-scale interstellar magnetic field in the Galactic disk, namely, the ring, the axisymmetric and the bisymmetric field models. Methods. We use the rotation measures (RMs) of low-latitude Galactic pulsars and combine them with their dispersion mea...

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