Effect of Radio Frequency Interference (RFI) Noise Energy on WERA Performance Using the “Listen Before Talk” Adaptive Noise Procedure on the West Florida Shelf

Merz, Clifford R.; Liu, Yonggang; Gurgel, Klaus-Werner; Peterson, Leif; Weisberg, Robert H.

doi:10.1016/b978-0-12-802022-7.00013-4

Cited by 11 publications

(9 citation statements)

References 15 publications

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“…In their analysis, Forget (2015) concludes that the average sampling period should have to adapt in order to retrieve the geophysical signal. The origin of such noise has not yet been fully understood, but various processes have been proposed to affect the radar measurements: changes in the velocity field during the duration of the radar measurement (Lipa et al, 2006;Merz et al, 2015), of radio frequency interferences (Lipa et al, 2006), and signal sampling (Liu et al, 2014).…”

Section: Retrieval From Coastal Hf Radarmentioning

confidence: 99%

Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated

Isern‐Fontanet

Ballabrera-Poy

Turiel

et al. 2017

Nonlin. Processes Geophys.

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Abstract. Ocean currents play a key role in Earth's climate -they impact almost any process taking place in the ocean and are of major importance for navigation and human activities at sea. Nevertheless, their observation and forecasting are still difficult. First, no observing system is able to provide direct measurements of global ocean currents on synoptic scales. Consequently, it has been necessary to use sea surface height and sea surface temperature measurements and refer to dynamical frameworks to derive the velocity field. Second, the assimilation of the velocity field into numerical models of ocean circulation is difficult mainly due to lack of data. Recent experiments that assimilate coastal-based radar data have shown that ocean currents will contribute to increasing the forecast skill of surface currents, but require application in multidata assimilation approaches to better identify the thermohaline structure of the ocean. In this paper we review the current knowledge in these fields and provide a global and systematic view of the technologies to retrieve ocean velocities in the upper ocean and the available approaches to assimilate this information into ocean models.

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Section: Retrieval From Coastal Hf Radarmentioning

confidence: 99%

Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated

Isern‐Fontanet

Ballabrera-Poy

Turiel

et al. 2017

Nonlin. Processes Geophys.

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“…During these experiments, the oblique-incidence sounding was first adopted to choose the optimum operating frequency, and then the Doppler spectrum of the echoes from the ocean was obtained with the LFMCW [126,156]. This is similar to the “listen before talk” procedure in HF radar applications [157]. …”

Section: Remote Sensing Applications Of Wiobss Operating At Low Trmentioning

confidence: 99%

Wuhan Ionospheric Oblique Backscattering Sounding System and Its Applications—A Review

Shi

Yang

Jiang

et al. 2017

Sensors

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For decades, high-frequency (HF) radar has played an important role in sensing the Earth’s environment. Advances in radar technology are providing opportunities to significantly improve the performance of HF radar, and to introduce more applications. This paper presents a low-power, small-size, and multifunctional HF radar developed by the Ionospheric Laboratory of Wuhan University, referred to as the Wuhan Ionospheric Oblique Backscattering Sounding System (WIOBSS). Progress in the development of this radar is described in detail, including the basic principles of operation, the system configuration, the sounding waveforms, and the signal and data processing methods. Furthermore, its various remote sensing applications are briefly reviewed to show the good performance of this radar. Finally, some suggested solutions are given for further improvement of its performance.

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“…LBT is part of the so-called fair coexistence code of practice and is included the regulatory requirements worldwide in several applications, from medical to communications [12,13]. Within the HFR operator's community, only phased array systems routinely implement the LBT mode with dynamical adaptation at their installations [14]. Typically, a frequency pre-scan is made across the entire licensed band before each data acquisition.…”

Section: Introductionmentioning

confidence: 99%

Implementation of the Listen-Before-Talk Mode for SeaSonde High-Frequency Ocean Radars

Cosoli

2020

JMSE

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The International Telecommunication Union (ITU) Resolution 612, in combination with Report ITU-R M2.234 (11/2011) and Recommendation ITU-R M.1874-1 (02/2013), regulates the use of the radiolocation services between 3 and 50 MHz to support high frequency oceanographic radar (HFR) operations. The operational frame for HFR systems include: band sharing capabilities, such as synchronization of the signal modulation; pulse shaping and multiple levels of filtering, to reduce out-of-band interferences; low radiated power; directional transmission antenna, to reduce emission over land. Resolution 612 also aims at reducing the use of spectral bands, either through the application of existing band-sharing capabilities, the reduction of the spectral leakage to neighboring frequency bands, or the development and implementation of listen-before-talk (LBT) capabilities. While the LBT mode is operational and commonly used at several phased-array HFR installations, the implementation to commercial direction-finding systems does not appear to be available yet. In this paper, a proof-of-concept is provided for the implementation of the LBT mode for commercial SeaSonde HFRs deployed in Australia, with potential for applications in other networks and installations elsewhere. Potential critical aspects for systems operated under this configuration are also pointed out. Both the receiver and the transmitter antennas may lose efficiency if the frequency offset from the resonant frequency or calibration pattern are too large. Radial resolution clearly degrades when a dynamical adaptation of the bandwidth is performed, which results in non-homogeneous spatial resolution and reduction of the quality of the data. A recommendation would be to perform the LBT-adapt scans after a full measurement cycle (1-h or 3-h, depending on the system configuration) is concluded. Mutual cross-interference from clock offsets between two HFR systems may bias the frequency scans when the site computers controlling data acquisitions are not properly time-synchronized.

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Effect of Radio Frequency Interference (RFI) Noise Energy on WERA Performance Using the “Listen Before Talk” Adaptive Noise Procedure on the West Florida Shelf

Cited by 11 publications

References 15 publications

Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated

Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated

Wuhan Ionospheric Oblique Backscattering Sounding System and Its Applications—A Review

Implementation of the Listen-Before-Talk Mode for SeaSonde High-Frequency Ocean Radars

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