Digital Telemetry Networks

Refraction Technology Inc. (formerly known as REF TEK established in 1975) became a part of Trimble Navigation Limited on October 4, 2012. Hereinafter all references to REF TEK (which is now a Trimble brand name) have been changed to Trimble Navigation (Trimble).

Trimble is the supplier of REF TEK equipment to the University of California, San Diego (UCSD) for the IDA program, which is a major portion of the IRIS/GSN program.

Trimble has long experience in the industry (since 1975) supplying digital real-time telemetry networks, including turnkey networks, worldwide. In fact we were the first company to install the first ever digital seismological telemetry network for UCSD in the US in 1981: The ANZA seismological network. Since then, we have been supplying error-corrected digital telemetry for regional and national networks for research and public safety purposes worldwide. Until very recently, Trimble had 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, it nevertheless demonstrates the use of our instruments with links other than narrow band, voice-grade phone lines or radios and the use of workstations for communication and acquisition.

Trimble’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.
Date Description of Network Organization Operating Network Communication Media
2012 Aswan Dam Strong-Motion Array (in progress) National Research Institute of Astronomy and Geophysics (NRIAG) GSM
2010 Telemetry network in North-East of India (in progress) India Meteorological Department (IMD), New Delhi, India VSAT
2009 Jordan National Seismic Telemetry network Jordan Seismological Observatory (JSO), Amman, Jordan VSAT
2008 Zaragoza Bridge Monitoring system Direccion General de Obras Publicas del D.F. & Terracon, Mexico City, Mexico Spread Spectrum Radio
2007 Dam Monitoring Telemetry network Theri Hydro Dam Corporation, India Spread Spectrum Radio
2006 DAM monitoring system EDELCA,Venezuela Spread Spectrum Radio
2006 German Indonesian Tsunami Early Warning System GeoForschungsZentrum Potsdam (GFZ) Global VSAT communication
2005 National Operative Telemetry System for Seismological Information (NOTSSI) Geophysical Institute Bulgarian Academy of Sciences, Sofia, Bulgaria ISDN, VPN, MAN
2004 Seismic Telemetry Network Institute of Physics of the Earth (IPE), Masaryk University, Brno, Czech Republic Spread Spectrum Radio
2002 Seismograph Telemetry Network around Edinburgh British Geological Survey UHF
2000 Seismographic Aftershock Monitoring System (SAMS) Test Ban Monitoring Spread Spectrum radio
2000 Small Aperture Infrasound array Federal Institute for Geosciences and Natural Resources, BGR (Bundesanstalt fuer Geowissenschaften und Rohstoffe), Hannover, Germany GSM
1999 New Delhi Telemetry Network India Meteorological Department, Delhi, India VSAT
1998 Puerto Rico National Telemetry Network University of Puerto Rico, Mayaguez UHF, microwave, ISDN
1998 Tsunami Warning Network US Geological Survey, Golden, Colorado UHF
1997 Friuli Network Instituto Nazionale de Geofisico/Civil Protection, Italy Dial-up
1997 Thailand National Telemetry Network Thailand Meteorological Dept. VSAT, Dial-up
1997 Kobe Network Geological Survey of Japan (expansion) ISDN
1997 San Calixto, Bolivia Network San Calixto Observatory UHF
1996 Kuwait National Network Kuwait Institute for Scientific Research (KISR) UHF
1996 Nor-Oeste Argentino INPRES, Argentina VHF/UHF, dial-up
1996 Kobe Network Geological Survey of Japan ISDN
1995 Southern Great Basin Network University of Nevada, Reno (additional stations) UHF, VSAT
1995 Chile Network University of Chile UHF
1994 Virginia Network Virginia Polytechnic Institute (Virginia Tech) UHF
1994 Nuevo Cuyo Network INPRES, Argentina VHF/UHF, dial-up
1992 Southern Great Basin Network University of Nevada, Reno UHF, VSAT
1990 Kyrgyz Telemetry Network US/Russia Joint Seismic Program UHF (now upgraded to spread spectrum radio)
1990 Kyrgyz Dense Telemetered Array US/Russia Joint Seismic Program UHF (now upgraded to spread spectrum radio)
1989 SMU Deployable Array Southern Methodist University UHF
1988 Perry Nuclear Power Plant Network Cleveland Electric Illuminating UHF
1988 IDA (International Deployment of Accelerometers) University of California, San Diego, Scripps Institution Global Dial-up
1987 Parkfield Early Warning Network US Geological Survey, Menlo Park UHF
1987 The Geysers Network University of California, Lawrence Berkeley Laboratory/US Geological Survey UHF
1987 Parkfield Differential Ground Motion Array US Geological Survey, Menlo Park Cable Telemetry
1986 Portable Telemetry Array University of California, Lawrence Livermore Laboratory UHF
1985 Parkfield High Frequency Array University of California, Berkeley UHF
1983 Four networks in Italy ISMES, Bergamo UHF
1981 ANZA Network University of California, San Diego, Scripps Institution UHF, Microwave