Results 61 to 70 of about 1,234 (185)

Study on the Detectability of the Sky-Surface Wave Hybrid Radar

Journal of Applied Mathematics, 2014
Working in the HF (high-frequency) band and the transmitter and receiver locating separately, the sky-surface wave hybrid radar both has the capabilities of the OTHR (over-the-horizon radar) and the advantage of the bistatic radar. As the electromagnetic
Hou Chengyu, Ke Guo, Shi Tiange, Wang Yuxin   +3 more
doaj   +1 more source

A Statistical Examination of the Spatial Correlations of HF Ionospheric Absorption Signatures Using the GO‐Canada Riometer Network

Journal of Geophysical Research: Space Physics, Volume 129, Issue 11, November 2024.
Abstract A network of 30‐MHz riometers distributed across Canada have been monitoring auroral absorption for decades. Electron precipitation can cause enhanced densities to develop below ∼100 km where the higher neutral density can cause absorption of High Frequency (HF) signals.
R. G. Gillies, E. Spanswick, S. Skone
wiley   +1 more source

A Geometric Barycenter-Based Clutter Suppression Method for Ship Detection in HF Mixed-Mode Surface Wave Radar

Remote Sensing, 2019
The nonhomogeneous clutter is a major challenge for ship detection in high-frequency mixed-mode surface wave radar. In this paper, a geometric barycenter-based reduced-dimension space-time adaptive processing method is proposed to suppress the clutter ...
Jiazhi Zhang, Xin Zhang, Weibo Deng, Lei Ye, Qiang Yang   +4 more
doaj   +1 more source

HiCIRF: a high-fidelity HF channel simulation [PDF]

, 2012
A high-fidelity HF channel simulation has been developed that is suitable for Over-the-Horizon Radar (OTHR) and HF communication system design studies and test planning.
Gavin St. John, Sergey V. Fridman, L. J. Nickisch, St. John, G., Fridman, S., Hausman, M., C. J. Coleman, Nickisch, L., Coleman, C., Mark A. Hausman   +9 more
core   +1 more source

A tale of four cities: Neighbourhood diversification and residential desegregation in and around England's ‘no majority’ cities

The Geographical Journal, Volume 190, Issue 2, June 2024.
Short Abstract Birmingham, Leicester, London and Manchester have emerged as England's only ‘no majority’ cities, where no single ethnic group forms more than 50% of the population. This paper looks at where the diversification of these cities has continued over the period from 2001 to 2021 or whether the reduction in the number of White British has led
Richard Harris
wiley   +1 more source

Unapređenje performansi izahorizontskih radara zasnovano na novoj arhitekturi sistema

, 2023
Istraživanje ove doktorske disertacije rezultiralo je u razvoju naprednog rešenja za praktičnu primenu izahorizontnog radarskog sistema (OTHR). Ovaj doprinos obuhvata suštinske izmene u arhitekturi sistema, kao i hardverskom dizajnu i izradi antenskog ...
Džolić, Bojan
core   +3 more sources

Field collections and environmental DNA surveys reveal topographic complexity of coral reefs as a predictor of cryptobenthic biodiversity across small spatial scales

Environmental DNA, Volume 6, Issue 3, May–June 2024.
Ordination of the 14 sampling sites (numbers) using a non‐metric multidimensional scaling (NMDS) based on the Bray‐Curtis dissimilarities of the 13 microhabitats. This means the 14 sites are placed in respect to their similarity in microhabitats of which the six most abundant across sites are displayed in orange.
O. B. Brodnicke, M. R. Jensen, P. F. Thomsen, T. Brorly, B. L. Andersen, S. W. Knudsen, K. Præbel, S. J. Brandl, M. J. Sweet, P. R. Møller, K. Worsaae   +10 more
wiley   +1 more source

Use of adaptive non-causal transmit beamforming in OTHR: Experimental results

, 2008
Copyright © 2008 IEEEWe report results from an experiment that applied multiple-input multiple-output (MIMO) waveform techniques to over-the-horizon radar (OTHR).
Frazer, G., Y. I. Abramovich, Abramovich, Y., Johnson, B., G. J. Frazer, B. A. Johnson   +5 more
core   +1 more source

High‐Latitude Off‐Great Circle Propagation Associated With the Solar Terminator

Radio Science, Volume 59, Issue 5, May 2024.
Abstract Large‐scale ionospheric gradients associated with the solar terminator can deflect high frequency (HF) radio waves to off‐great circle paths during the morning and evening, negatively impacting technologies reliant on HF radio wave propagation.
T. G. Cameron, R. A. D. Fiori, G. W. Perry, J. J. Ruck, T. Thayaparan   +4 more
wiley   +1 more source

Statistical Analysis of Off‐Great Circle Radio Wave Propagation in the Polar Cap

Radio Science, Volume 59, Issue 4, April 2024.
Abstract High latitude ionospheric density structures such as polar cap patches and arcs are capable of deflecting high frequency (HF) radio waves to off‐great circle paths, and are likely detrimental to technologies dependent on HF radio propagation.
T. G. Cameron, R. A. D. Fiori, G. W. Perry, A. Spicher, T. Thayaparan   +4 more
wiley   +1 more source