HFSurface Wave Radar

Abstract

HF surface wave radar (HFSWR) has been recognized and accepted as an important tool for ocean remote sensing for more than four decades. In this article, a comprehensive tutorial of such an ocean sensor is presented. It begins with the concept of HFSWR. Next, the history of HFSWR is briefly reviewed. Then, the classification of HFSWR in terms of waveform, array signal processing technique, the number of operating frequencies, and configuration geometry is described in detail. Subsequently, the state‐of‐the‐art applications of this type of ocean radar for sea surface current, and wave parameter measurements, wind mapping, and hard targets detection and tracking are presented. The working principles and data processing associated with each application are also explained. The remaining challenges and future trends are also discussed.

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

“…The operation of HFR systems in Australia is dependent upon the fulfillment of the ITU regulation, particularly for what concerns the band sharing capabilities, the interference mitigation measures and the reduction of the offband leakage. ITU Report M.2234 and Recommendation M.1874-1 [4,5] describe some of the possible mitigation measures, such as directional transmit antennas to reduce signal transmission over land or at unwanted directions, the use of pulse-shaping and the band sharing capabilities, and discuss of the possible implementation of the listen-before-talk and bandwidth adaptation mode and report possible significant impacts on data quality which is deemed unacceptable by the HFR operators. SeaSonde systems already implement the GPS syncronization capability, that allows for multiple sites to operate in the same band without mutual interference and allow for a more efficient use of the radio frequency spectrum.…”

“…Along the coasts of the US, for instance, more than 100 HFR systems are presently in operation, and the number of deployments steadily increases both in the Asia-Pacific regions and Europe. Extensive validation analyses and deployments in a variety of environments have also proven their general reliability [1][2][3][4].…”

“…Other HFR systems are also available, such as the PISCES or the University of Hawaii's HFRs. See, for instance, [1][2][3][4] and references herein for a more exhaustive literature review and for an assessment of their interoperability.…”

The Traveling Wave Loop Antenna: A Terminated Wire Loop Aerial for Directional High-Frequency Ocean RADAR Transmission

“…High Frequency RADAR (HFR) measurements of surface currents in the coastal ocean have become a standard and cost-effective component for ocean observing systems globally [1][2][3]. Developed more than four decades ago [4], oceanographic HFR provides highly accurate synoptic observation of large scale coastal circulation features at high temporal and spatial resolutions not readily obtained using conventional instrumentation [5,6].…”

“…Developed more than four decades ago [4], oceanographic HFR provides highly accurate synoptic observation of large scale coastal circulation features at high temporal and spatial resolutions not readily obtained using conventional instrumentation [5,6]. HFRs now constitute a fundamental component of coastal observing networks, due to: their utility in understanding processes such as air-sea interaction, coastal circulation and tidal flows; their ability to support search and rescue operations, and the direction toxic-spill mitigation activities; and as tsunami early-warning systems [1][2][3].…”