Roarty H.J.,New Brunswick Laboratory |
Barrick D.E.,Codar Ocean Sensors, Ltd. |
Kohut J.T.,New Brunswick Laboratory |
Glenn S.M.,New Brunswick Laboratory
Turkish Journal of Electrical Engineering and Computer Sciences | Year: 2010
This paper describes the development of the SeaSonde High Frequency Radar system into a dual-use application for the mapping of ocean surface currents and detection of ships at sea. This development entailed the creation of a new radar waveform that would permit this dual-use as well as a detection algorithm to identify the ships in the radar spectra. The detection algorithm utilizes two methods for calculating a background signal level: an infinite impulse response (IIR) filter and a two-dimensional median filter. These two methods are employed simultaneously with multiple length averaging times to maximize the number of detections. The initial phase of development focused on improving the radar waveform to maximize the results for ship detection while still retaining the ability to measure surface currents. The latter phase of the development concentrated on testing the detection algorithm on a known vessel in different environmental conditions. Source
Kjelaas A.G.,CODARNOR AS |
Whelan C.,Codar Ocean Sensors, Ltd.
Sea Technology | Year: 2011
CODARNOR AS has partnered with CODAR Ocean Sensors, QUALITAS Remos (Madrid, Spain) and the Norwegian Meteorological Institute, to develop a rapid-response SeaSonde for the rugged and remote Norwegian coastline in response to the Oil Spill Response 2010 launched by the Norwegian Clean Seas Association for Operating Companies and the Norwegian Coastal Administration. The objectives involves the development of a mobile SeaSonde high-frequency radar unit that can be rapidly deployed to the coast of Norway to aid in effective and efficient oil spill response. The project aimed to accomplish this through developing a data service that provides high-quality SeaSonde-derived 2D current fields to the Norwegian Meteorological Institute in near real time. High-frequency radar currents from the nine-day experiment in September 2010, during which both radars operated, were blended with ocean model current fields to produce a continuous gridded data set. Source
Agency: Department of Commerce | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 94.98K | Year: 2010
Of more than 100 HF Radars operating within the Integrated Ocean Observing System (IOOS), more than half run either without recommended receive antenna pattern calibrations or with out-of-date calibrations, despite potential compromises to data quality. Cost is the primary inhibitor of frequent calibration, which generally requires a technician to drive a small vessel with mounted transponder in arcs around the antenna. Large vessels now broadcast their positions and speed approximately every 10 seconds using the Automatic Identification System (AIS). Echo from these vessels also appear as signals in real-time HF Doppler spectra. We propose using AIS ship position and speed, along with corresponding HF Doppler ship echo, to determine receive antenna patterns in near real time. The methods proposed here will result I a software product which would both reduce the cost of calibration of IOOS HF radars and significantly improve IOOS surface current data quality.
Agency: Department of Commerce | Branch: National Oceanic and Atmospheric Administration | Program: SBIR | Phase: Phase II | Award Amount: 399.88K | Year: 2011
Over 300 HF RADARs worldwide are producing ocean surface data that is used in oil spill response, search & rescue, vessel traffic management, and research. In the U.S. there are 100+ systems supplying real-time data to the Coast Guard, NOAA IOOS, OR&R and other operational groups. To provide the highest quality data to stakeholders, systems should be calibrated by measuring the receive antenna pattern. For the typical HF radar, this measurement is currently made with a portable transponder on a boat 1-2 km away. This method, while robust, is costly and limited by sea conditions. We demonstrated in Phase I that by associating AIS vessel identifications, which provide ship positions, with vessel radar echoes in HF radar data it is possible to reproduce the antenna pattern. The objective of Phase II research is to implement the method operationally. The prototype will consist of software to acquire AIS ship data and combine it with HF radar cross-spectra to produce antenna pattern measurements and their statistics. To accomplish this objective we will answer the remaining research questions from Phase I, expand the method to other operational HF radar bands (5, 25 and 42 MHz), and develop quantitative data quality metrics.
Codar Ocean Sensors, Ltd. | Date: 2011-08-31
An antenna configuration is described for high frequency (HF) or very high frequency (VHF) radars contained in a single vertical post. The radar may include a vertical dipole or monopole transmitting antenna collocated with a three-element receive antenna. The three antennas including two crossed loops and a vertical element are used in a direction-finding (DF) mode. Isolation between the three antennas produces high quality patterns useful for determining target bearings in DF mode. The single vertical post is sufficiently rigid mechanically that it may be installed along a coast without guy wires.