HF radar

The Institute of Marine Sciences (ISMAR) of the
National Research Council of Italy (CNR) established a High
Frequency (HF) Coastal Radar Network for the measurement
of the velocity of surface currents in coastal seas. The network
consists of four HF radar systems located on the coast of the
Gargano Promontory (Southern Adriatic, Italy). The network
has been operational since May 2013 and covers an area of
approximately 1700 square kilometers in the Gulf of Man-
fredonia. Quality Assessment (QA) procedures are applied for
the systems deployment and maintenance and Quality Control
(QC) procedures are performed on the data generation pipeline.
The network provides hourly sea surface velocity data in real-
time mode, that are published for visualization and access. In
order to produce data in interoperable formats, according to the
standards of Open Geospatial Consortium (OGC) for the access
and delivery of geospatial data, a netCDF architecture has been
defined on the basis of the Radiowave Operators Working Group
(US ROWG) recommendations and compliant to the Climate
and Forecast (CF) Metadata Conventions CF-1.6. The hourly
netCDF files are automatically attached to a Thematic Real-time
Environmental Distributed Data Services (THREDDS) catalog
supporting OGC compliant distributions and protocols for data
visualization, metadata interrogation and data download. HF
radar data have been validated by comparison with velocities
measured by drifters deployed within the radar coverage. The
data produced by the ISMAR HF radar network are presently
used in a number of applications, ranging from oil spill and SAR
to fishery and coastal management applications.

Northern Radar Inc (NRI) is in the process of developing a high-frequency software-defined radar (HF-SDR). The transceiver of the system is implemented using software-defined radio (SDR) technology, and the radar utilizes phased-array antennas. In its current set-up, the system is designed to operate in the surface-wave mode. Hence, its main end-market application is oceanography. The SDR is a generic radio communication system in which components that have been typically implemented in hardware (e.g., the mixer, modulator, demodulator, detectors, etc.) are instead implemented by means of software on a personal computer or an embedded device. When compared to standard state-of-the-art HF radars in the market today, the two main advantages of the SDR-based system are flexibility and cost-efficiency.
Figure 1 illustrates the overall architecture of the HF-SDR system. Primarily, SDRs connected to a host computer function as the transceiver of the system. To provide for long-term clock stability and to synchronize the receive and transmit channels across multiple SDRs, a GPS disciplined oscillator (GPSDO) is used. For demonstration purposes, a representative range-Doppler map, acquired using this system from the on-site HF antennas, installed by NRI for the HF-ROSA project [1] at the former Naval Station Argentia, Newfoundland [2], is shown in Figure 2. In the full-paper version of this abstract, a more thorough description will be offered along with additional results.


REFERENCES
[1] High Frequency Radar Ocean Surface Applications (HF-ROSA). (2014, 12) Memorial University of Newfoundland. [Online]. Available: http://hfrosa.engr.mun.ca/
[2]  Naval Station Argentia. (2014, 12) Wikipedia. [Online]. Available: http://en.wikipedia.org/wiki/Naval_Station_Argentia

High Frequency Radar (HFR) is a land-based remote sensing instrument offering a unique insight to coastal ocean variability, by providing synoptic, high frequency and high resolution data at the ocean atmosphere interface. HFRs have become invaluable tools in the field of operational oceanography for measuring surface currents, waves and winds, with direct applications in different sectors and an unprecedented potential for the integrated management of the coastal zone. In Europe, the number of HFR networks has been showing a significant growth over the past 10 years, with over 50 HFRs currently deployed and a number in the planning stage. There is also a growing literature concerning the use of this technology in research and operational oceanography. A big effort is made in Europe toward a coordinated development of coastal HFR technology and its products within the framework of different European and international initiatives. One recent initiative has been to make an up-to-date inventory of the existing HFR operational systems in Europe, describing the characteristics of the systems, their operational products and applications. This paper offers a comprehensive review on the present status of European HFR network, and discusses the next steps toward the integration of HFR platforms as operational components of the European Ocean Observing System, designed to align and integrate Europe's ocean observing capacity for a truly integrated end-to-end observing system for the European coasts.