Results 11 to 20 of about 794,325 (131)

Over‐the‐Horizon Direct Positioning With Ionospheric Heights Priors

IET Radar, Sonar & Navigation
This study addresses positioning errors in high‐frequency (HF) over‐the‐horizon (OTH) localisation that arise from inaccuracies in ionospheric virtual height measurements.
Shuyu Zheng, Haiying Zhang, Xiuquan Dou
doaj   +2 more sources

Modern spectral analysis in HF radar remote sensing. [PDF]

, 1998
High-Frequency (HF) radar systems are currently used to collect wave data. By applying spectral analysis methods, such as the Fast Fourier Transform (FFT) method, to the radar backscatter from the ocean surface, the so-called Doppler spectrum is ...
Vizinho, A
core   +6 more sources

Ionospheric electron heating, optical emissions, and striations induced by powerful HF radio waves at high latitudes: Aspect angle dependence [PDF]

, 2003
In recent years, large electron temperature increases of 300% (3000 K above background) caused by powerful HF-radio wave injection have been observed during nighttime using the EISCAT incoherent scatter radar near Tromsø in northern Norway.
Rietveld, M. T., Kosch, Mike J., Leyser, T. B., Blagoveshchenskaya, N. F., Kornienko, V. A., Yeoman, T. K.   +5 more
core   +5 more sources

Nightside studies of coherent HF radar spectral width behaviour [PDF]

, 2002
A previous case study found a relationship between high spectral width measured by the CUTLASS Finland HF radar and elevated electron temperatures observed by the EISCAT and ESR incoherent scatter radars in the post-midnight sector of magnetic local time.
J. A. Davies, Davies, J.A., Eglitis, P., P. Eglitis (7605143), P. Eglitis, Woodfield, E.E., Lester, M., Lockwood, M., Lockwood, Mike, M. Lester, J. A. Davies (4412452), T. K. Yeoman (7601525), T. K. Yeoman, M. Lester (7589660), Davies, J. A., M. Lockwood, M. Lockwood (7612331), E. E. Woodfield (7590071), E. E. Woodfield, Yeoman, T. K., Yeoman, T.K., Woodfield, E. E.   +21 more
core   +3 more sources

A CFAR‐like detector based on neural network for simulated high‐frequency surface wave radar data

IET Radar, Sonar &Navigation, Volume 17, Issue 5, Page 859-875, May 2023., 2023
This article presents a deep neural network‐based constant false alarm rate detector for high‐frequency surface wave radar. A deep neural network is trained to identify fluctuation parameters of each cell of a range‐Doppler power spectrum based on the patterns present in the neighbouring cells.
Rômulo Fernandes da Costa, Diego da Silva de Medeiros, Osamu Saotome, Renato Machado   +3 more
wiley   +1 more source

Joint correction method for ionospheric phase pollution of high‐frequency sky‐surface wave radar based on adaptive optimal path

IET Radar, Sonar &Navigation, Volume 17, Issue 4, Page 701-718, April 2023., 2023
Abstract The high‐frequency (HF) hybrid sky‐surface wave system is a new early warning radar. However, due to the influence of bistatic angle and ionospheric phase path disturbance, the echo spectrum will be widened, which seriously affects the ability of detecting slow targets of ships.
Yajun Li, Zhuoqun Wang, Wenhao Zhang, Zhuhao Lu, Lin Xu, Zhicheng Wang   +5 more
wiley   +1 more source

Impacts of Auroral Precipitation on HF Propagation: A Hypothetical Over‐the‐Horizon Radar Case Study

Space Weather, Volume 19, Issue 12, December 2021., 2021
Abstract Over‐the‐horizon radar (OTHR) systems operating in the high‐frequency (HF) band (3–30 MHz) are unique in their ability to detect targets at extreme ranges, offering cost‐effective large‐area surveillance. Due to their reliance on the reflective nature of the ionosphere in this band, OTHR systems are extremely sensitive to ionospheric ...
Joshua J. Ruck, David R. Themens
wiley   +1 more source

Challenges in Specifying and Predicting Space Weather

Space Weather, Volume 19, Issue 2, February 2020., 2021
Abstract Physics‐based Data Assimilation (DA) has been shown to be a powerful technique for specifying and predicting space weather. However, it is also known that different data assimilation models simulating the same geophysical event can display different space weather features even if the same data are assimilated.
R. W. Schunk, L. Scherliess, V. Eccles, L. C. Gardner, J. J. Sojka, L. Zhu, X. Pi, A. J. Mannucci, A. Komjathy, C. Wang, G. Rosen   +10 more
wiley   +1 more source

Superdarn radar HF propagation and absorption response to the substorm expansion phase [PDF]

, 2002
International audienceCoherent scatter HF ionospheric radar systems such as SuperDARN offer a powerful experimental technique for the investigation of the magnetospheric substorm.
J. A. Davies, Milan, S. E., Honary, F., T. K. Yeoman (7601525), J. A. Davies (4412452), J. K. Gauld (7674179), F. Honary (7604621), T. K. Yeoman, Davies, J. A., S. E. Milan, J. K. Gauld, F. Honary, Yeoman, T. K., S. E. Milan (7594526), Gauld, J. K.   +14 more
core   +2 more sources

Multi-frequency HF radar measurements of artificial F-region field-aligned irregularities [PDF]

, 2004
International audienceWe present radar backscatter power measurements using the CUTLASS HF radar at Hankasalmi, Finland from F-region field-aligned irregularities induced by HF radio pumping with the EISCAT Heating facility.
A. Senior, Rietveld, Michael T., Kosch, M.J., Borisov, N. D., Honary, F., Rietveld, M. T., Senior, A., T. K. Yeoman, Borisov, N.D., M. T. Rietveld, Kosch, M. J., M. J. Kosch, F. Honary, Yeoman, T. K., N. D. Borisov, Yeoman, T.K.   +15 more
core   +2 more sources