Introducing Refraction Technology, Inc. REF TEK was founded in 1975 to produce quality, niche products for the land, marine and oil exploration markets. In 1981, REF TEK supplied a digital telemetry system to the University of California, San Diego for use in the ANZA area. This network was the first digital telemetry system in the U.S.A. and is successfully operating to this day. IRIS (Incorporated Research Institutions for Seismology), a consortium of 104 U.S.A. universities, was formed in 1984. IRIS focused on two research arenas: the Global Seismological Network (GSN) and the Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL). One of the prime goals of PASSCAL was to procure a large pool of portable instruments to record reflection and refraction and passive broadband data for elucidation of the crust down to the mantle. Specifications were issued in a competitive bid, and the REF TEK approach was chosen. REF TEK has delivered more than 1000 digital acquisition stations to IRIS under this award. In 1991, REF TEK adapted a Hewlett-Packard 24-bit digitizer to provide a high resolution digitizing and recording system for the International Deployment of Accelerometers (IDA) of the University of California, San Diego. IDA is now part of the IRIS/GSN program. Approximately 30% of all GSN stations use instruments supplied by REF TEK. More than 6,500 REF TEK Instruments are presently being used in the following applications:
Since our inception, REF TEK has continued to research and expand our products and capabilities to meet the changing needs of the seismological community. Almost all instruments sold now have 24-bit digitizing capability and GPS timing. A radically new data logger design is the product of the advancements in gate arrays which allow the use of real-time operating systems and communications software able to use the Internet as well as updated microcomputer architecture. Power is always a critical issue for any seismological application. The 3rd Generation Broadband Seismic Recorder, model 130-01, utilizes new power logic and is the industry leader in low power consumption. With the development of the model 130-01 with lower power consumption, lighter weight and smaller size, REF TEK has again surpassed our own standard. See the product section for more information on the advancements of the model 130-01. |
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Global Network and Telemetry Experience REF TEK is the supplier to the University of California, San Diego for the IDA program, which is a major portion of the IRIS/GSN program. REF TEK started supplying digital telemetry for seismic applications in 1981, when it was approached by UCSD to supply digital telemetry for the ANZA Network, the first such network in the USA. Since then, REF TEK has been supplying error-corrected digital telemetry for regional and national networks for research and public safety purposes worldwide. Until very recently, REF TEK has been the only commercial supplier of error-corrected digital telemetry. Now most investigators understand the problems introduced in processing by bit errors, including finding automatic phase picks. The Southern Great Basin Seismic Network (SGBSN) is a large 42 station network that monitors seismicity around the Yucca Mountain, Nevada large nuclear waste disposal area. It is operated by the University of Nevada, Reno. The geometrical concept for this network has been to deploy radio telemetry subnets with nodes (or hubs) that then forward the data to Reno via microwave. At Reno, the acquisition and processing is accomplished on SPARC workstations. Originally, when part of the network was first deployed by the US Geological Survey, the nodes transmitted via satellite (VSAT) to the USGS National Earthquake Information Center in Golden, Colorado. This network emphasizes three relevant aspects: the hub concept, the use of a UNIX workstation in communication and acquisition, and satellite communication. The Geological Survey of Japan (GSJ) Network is a 16-station network deployed around the Kobe area to record aftershock seismicity. The communication vehicle is ISDN digital lines, and the processing is on UNIX workstations. Although, this network uses computer interfaces with REF TEK DAS units, nevertheless it demonstrates the use of REF TEK instruments with links other than narrow band, voice-grade phone lines or radios and the use of workstations for communication and acquisition. The table below is a list of digital telemetry networks supplied by REF TEK. REF TEK’s innovation in network technology, the Advanced Seismic Networks approach, offers customers telemetry stations and networks for a variety of communications media including IP networks, satellite and radio telemetry, analog and digital lines. The two most recent installations in Table 1 utilize the Advanced Seismic Networks approach. DIGITAL TELEMETRY NETWORKS SUPPLIED BY REFRACTION TECHNOLOGY, INC.
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