Results 21 to 30 of about 345,531 (342)

An influence of the covariance between single orbit parameters on the accuracy of observations of the pseudo-ranges and phase differences

open access: yesMetrology and Measurement Systems, 2020
The possibilities to improve values of the satellite orbit elements by employing the pseudo-ranges and differences of carrier phase frequencies measured at many reference GPS stations are analysed. An improvement of orbit ephemeris is achieved by solving
Skeivalas Jonas   +3 more
doaj   +1 more source

Measurement-based analysis of delay-Doppler characteristics in an indoor environment [PDF]

open access: yes, 2016
An analysis of delay-Doppler characteristics in the presence of moving people is presented for short-range communication in an indoor environment. Channel-sounding measurements have been carried out at 3.6 GHz in a crowded university hall during several ...
Hanssens, Brecht   +4 more
core   +1 more source

Performance analysis of DSSS- and CSS-based physical layer for IoT transmission over LEO satellites

open access: yesETRI Journal, 2022
To determine a suitable waveform for Internet of Things (IoT) transmission over low-Earth orbit (LEO) satellites, this paper reports the results of a performance comparison between chirp spread spectrum (CSS)-based LoRa and direct sequence spread ...
Sooyeob Jung   +5 more
doaj   +1 more source

Post-Newtonian Theory for Precision Doppler Measurements of Binary Star Orbits [PDF]

open access: yes, 1999
The determination of velocities of stars from precise Doppler measurements is described here using relativistic theory of astronomical reference frames so as to determine the Keplerian and post-Keplerian parameters of binary systems.
Brumberg V. A.   +16 more
core   +3 more sources

Modeling of Monopulse Radar Signals Reflected from Ground Clutter in a Time Domain Considering Doppler Effects [PDF]

open access: yesJournal of Electromagnetic Engineering and Science, 2020
To evaluate the performance of a monopulse radar system, it is necessary to accurately model radar return signals from the ground surface in a time domain.
Jeong-Hun Nam   +4 more
doaj   +1 more source

Non-invasive Ultrasound Doppler Effect Based Method of Liquid Flow Velocity Estimation in Pipe [PDF]

open access: yesArchives of Acoustics, 2023
This paper discusses the estimation of flow velocity from a multi-sensor scenario. Different estimation methods were used, which allow the effective measurement of the actual Doppler shift in a noisy environment, such as water with air bubbles, and on ...
Pawel Biernacki   +2 more
doaj   +1 more source

Theory of Dicke narrowing in coherent population trapping [PDF]

open access: yes, 2007
The Doppler effect is one of the dominant broadening mechanisms in thermal vapor spectroscopy. For two-photon transitions one would naively expect the Doppler effect to cause a residual broadening, proportional to the wave-vector difference.
A. Ben-Kish   +7 more
core   +2 more sources

Sharing a common origin between the rotational and linear doppler effects [PDF]

open access: yes, 2017
The well-known linear Doppler effect arises from the linear motion between source and observer, while the less well-known rotational Doppler effect arises from the rotational motion.
Allen   +40 more
core   +1 more source

Performance Evaluation of OTFS-NOMA Scheme for High Mobility Users

open access: yesSakarya University Journal of Computer and Information Sciences, 2023
Orthogonal Time Frequency Space (OTFS) is a promising approach which is widely employed in sixth generation (6G) wireless network systems. Because of its superior performance in high-mobility environments, OTFS modulation has received a lot of attention ...
Arif Başgümüş   +2 more
doaj   +1 more source

Lightweight and secure vehicle track verification scheme via broadcast communication channels

open access: yes网络与信息安全学报, 2023
In intelligent transportation systems, it is crucial for smart vehicles to broadcast real-time vehicle track messages to coordinate driving decisions and ensure driving safety.However, attackers can manipulate vehicle tracks by modifying timestamps or ...
Zhiqiang NING, Yuanyuan WANG, Chi ZHANG, Lingbo WEI, Nenghai YU, Yue HAO
doaj   +1 more source

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