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History of the High Frequency Doppler Radio program

Proposals and instrument selection

In February 1997, a proposal Δ was submitted to the National Science Foundation Major Research Instrumentation program, to establish at the University of Hawai'i a High Frequency Doppler Radio (HFDR) facility in support of coastal oceanography. The proposal received excellent peer reviews, and was funded in October 1997.

The state of the technology was first assessed. It was decided that a research-grade instrument, flexibly modifiable to follow the needs of specific experiments, would be prefered, and that estimation of the direction of targets through the more precise beam-forming technique was desirable.

Seven beam-forming HFDR systems existed in the world. OSCR, formerly manufactured by Marconi in the UK, was based on 15-year old technology and no longer produced. COSRAD, a joint venture between James Cook University and Telstra in Australia, was dropped from the market. PISCES in the UK and C-CORE in Canada were prototypes, not ready for commercial production. Kokusai Kogyo Co., Ltd. in Tokyo, and Metratek in the US, both had plans to market marine HF Doppler Radio instruments, but neither had completed their development.

The WERA, designed by Klaus Werner Gurgel at the University of Hamburg in Germany, was eventually selected. It uses a frequency modulated continuous wave, easy to monitor with laboratory equipment. The shared software source code was an asset. Finally, the Hamburg team had abundant peer-reviewed publications, establishing the success of the WERA.

Design and construction

The selection of the WERA was approved by the funding agency in September 1998, and a contract to build four units was awarded to the University of Hamburg in January 1999. The construction was subcontracted to Helzel Messtechnik, a small electronics business, the University of Hamburg retaining the overall design of the system. Construction began in February 1999.

Considerable progress in electronics had occurred since the design of the WERA prototype in 1992. It was decided to update the WERA with new Direct Digital Synthetizers (DDS) chips from Analog Devices. Unfortunately, Analog Devices experienced difficulties in delivering bug-free chips, and a working synthetizer could not be produced until Spring 2000. The first complete instrument was successfully tested in October 2000 in Gijon, Spain, during the EuroROSE project. The University of Hawai'i then authorized the construction of the remaining three instruments.

However, another procurement problem surfaced. The prototype used off-the-shelf analog-to-digital converters (ADC) manufactured by Analogic, Inc., controlled by a DEC Alpha computer. Unfortunately, Analogic dropped the 16-bit ADCs from their product line. The takeover of DEC by Compaq, and of Compaq by HP, also made the future of the Alpha computer uncertain. Since off-the-shelf ADC solutions with the required signal-to-noise performance could not be found without extensive testing, custom circuits based on the same ADC chip were designed by Helzel. An Intel-based compact-PCI computer was used as controller, the University of Hamburg porting their VXWork software to the Intel platform.

The four University of Hawai'i instruments with the new DDS and ADCs were eventually completed in November 2001, and shipped to Hawai'i where they were integrated into field-deployable containers, complete with air conditioning, power supply, computer and network interface.

Meanwhile, the advent of this new commercially-available phased array radar raised interest in the oceanographic community. The Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), in Trieste, Italy, was funded by the Consiglio Nazionale delle Ricerche (CNR) to purchase two additional instruments.

The University of Miami, the Proudman Laboratory in Liverpool, the Universite de Toulon-Var in France, the University of South Carolina, the Universitad de Baja California in Mexico, the Universitad de Conception in Chile and the Service Hydrographique et Oceanographique de la Marine in France, ordered WERAs soon after; by the end of 2006, more than twenty WERAs had been built, placing it as the world's preferred phased array HFDR instrument for measuring ocean currents.

Deployments and scientific programs

In a 3-month marathon field campaign from August to October 2002 involving more than forty scientists, technicians and students, five instruments were deployed in remote areas. Two were deployed until June 2003 in the framework of the Hawai'i Ocean Mixing Experiment, with funding from the National Science Foundation, and three until August 2004 along the Adriatic coast of Italy, with funding from the Office of Naval Research.