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Geobit collaborates with the University of Patras for innovative SHM solutions

Geobit collaborates with the University of Patras for innovative SHM solutions

A group of researchers, including graduate and undergraduate students of the University of Patras, Department of Civil Engineering [1], under the coordination and supervision of Prof. A. Dimas [2], developed a physical model of a floating offshore wind turbine generator in geometrical scale of 1:100 (Fig. 1). The coupled hydrodynamic and structural behavior of the model at stormy seas, under operational and parked conditions, was tested in the Wave Basin of the Hydraulic Engineering Laboratory of the Department [3], which is equipped with a paddle wavemaker. Several sea conditions were tested corresponding to wind strength up to 12 in the Beaufort scale.

GEObit-instruments designed and provided all the hardware to measure, monitor and record instantaneous acceleration at the top and at the base of the turbine pylon.

Picture 1

The GEObit SRI32S data-logger

Picture 2

The GEObit SM1500 acceleration sensor

Picture 3

The floating wind turbine physical model in the Wave Basin

Experimental Configuration

Two GEObit SM1500 [4] sensors (Fig. 3) combined with SRi32S [5] data-loggers (Fig. 1) were used for the acceleration monitoring.

The SM1500 sensors had to be modified to enable their attachment to the turbine model. The sensing elements were placed on ring PCB boards (Fig. 4) and the sensor electronics were housed separately into the typical SM1500 enclosure (Fig. 5). Extra attention was paid to create lightweight sensing parts and connection cables for avoiding add extra weight and tense to the model. Three acceleration elements were orthogonally placed on each ring; therefore, all axes were monitored at the top and at the bottom (sea level).

The acceleration signal from the modified accelerometers was recorded by two high-resolution SRi32S dataloggers (Fig. 6). Real-time signal plot was obtained at the Laboratory’s computer, so the researchers were able to monitor in real time the effect of the waves on the turbine model (Fig. 7).

In addition, one wave gauge at the seaward side of the wind turbine model (Fig. 3) was continuously measuring the free-surface elevation due to the incident waves.

Several regular and irregular wave conditions were reproduced in the Wave Basin in order to test the dynamic behavior of the floating offshore wind turbine under operational (wind speed less than 25 m/s) and parked (wind speed more than 25 m/s) conditions; the latter include severe wave conditions.

Picture 4

The GEObit SM1500 acceleration sensor upper ring

Picture 5 

The GEObit SM1500 and SRi32S sensor – dataloggers

Picture 6

The wind turbine physical model and the GEObit acceleration recording system

Picture 7

Acceleration plot on the PC

Experiment Video


The following research team contributed to the successful implementation of this project:

  • Liras Vasilios, Undergraduate Student (Univ. Patras, Department of Civil Engineering)
  • Vavouraki Argiro, MSc Student (Univ. Patras, Department of Civil Engineering)
  • Galani Kostantina, Postdoctoral Research Associate (Univ. Patras, Department of Civil Engineering)
  • Dimou Ioannis, Laboratory Staff (Univ. Patras, Department of Civil Engineering)
  • Dimas Athanassios, Professor (Univ. Patras, Department of Civil Engineering)
  • Spiliotopoulos Athanasios, Electrical Engineer (GEObit-Instruments)
  • Germenis Nikos, MSc Electronics Engineer (GEObit-Instruments)
Visit ISTI @ IUGG 2019 in Montreal

Visit ISTI @ IUGG 2019 in Montreal

Our USA representative, ISTI Inc is exhibiting at IUGG 2019.

Meet our team and learn about the latest offerings.  Paul Friberg & Sid Hellman will be available to answer your questions.

Visit us at booth #109, IUGG 2019

Montreal Canada | 8 – 17 July

There is no impact of the “week number rollover” issue on Geobit Instruments

There is no impact of the “week number rollover” issue on Geobit Instruments

Geobit Instruments are not affected by the GPS week rollover issue.

We are pleased to inform you that all GEObit digitizers are using Garmin GPS receivers for time synchronization, and they will not be affected by the GPS rollover issue. As a result, all our digitizers will continue operating properly. No action needs to be taken by GEObit Instruments users.

At GEObit, we are always working to offer state-of-the-art technology and high-reliability products, requiring the minimum possible maintenance.

What is the GPS Week Number Rollover (WNRO)?

The GPS system is world renowned for its ability to provide accurate and reliable positioning and timing information worldwide. The GPS satellites transmit to users the date and time accurate to nanoseconds. However, back in 1980, when the GPS system first began to keep track of time, the date and time were represented by a counter that could only count forward to a maximum of 1024 weeks, or about 19.7 years. After 1024 weeks had elapsed, this counter “rolled over” to zero, and GPS time started counting forward again.  This first rollover occurred in August of 1999. The second rollover will occur on April 6, 2019.

Is My Geobit Device Affected?

Our GPS supplier, Garmin, has anticipated and prepared for this event. Regardless, Garmin and Geobit have been performing exhaustive testing of current and legacy devices to determine if they will be affected by the GPS week number rollover.  Our testing shows the vast majority of Geobit devices will handle the WNRO without issues.

What is the Effect of a GPS Week Number Rollover Issue?

For GPS devices that are affected, after the rollover occurs, an incorrect date and time will be displayed. This incorrect time will also be used to timestamp track logs, compute sunrise and sunset, and other functions that rely upon the correct date and time. However, the positioning accuracy will not be affected. The device will continue to deliver the same positioning performance as before the rollover.

Geobit is exhibiting at AGU100, Washington DC

Geobit is exhibiting at AGU100, Washington DC

Geobit & ISTI join together at the AGU Fall Meeting in Washington, D.C. 10 – 14 Dec. 2018.

We are a team providing a complete seismic monitoring solution. Contact us through EarthImaging.com.

With 65+ years of combined experience, GEObit and ISTI are joining forces to become the most competitive and fastest growing joint venture group in the seismic monitoring services industry.

Providing state-of-the-art seismic instruments, network design, installation techniques, data monitoring and processing services, our group is able to deliver a cost-effective total solution to the energy exploration & production industry, especially to the oil, gas and geothermal sector. Our key benefits are that we produce in-house hardware and software while installing and maintaining the microseismic monitoring network to ensure a high level of data quality and availability. In other words, we make the technology – we apply the technology – we offer the technology.

We have worldwide experience having installed and operated seismic networks all over the world, from Indonesia/Papua jungle to the Middle East desert, from Alaska glaciers to Himalayan Mountains. In the USA, we are currently running many dedicated microseismic monitoring projects with over 200 stations installed in the past 10 years.

Visit us at booth #815, AGU 2018


Washington, D.C. USA  |  10 – 14 December


Meet our team and learn about the latest offerings. Dimitris Mourtzouchos & Nikos Germenis (Geobit), Paul Friberg & Sid Hellman (ISTI), and others will be available to answer your questions.

Walter E. Washington Convention Center

801 Mt. Vernon Place NW
Washington, DC, 20001

More information about AGU Fall Meeting 2018 may be found here.

More information on the Walter E. Washington Convention Center can be found here.

ISTI/Geobit at the Seismic Instrumentation Technology Symposium 2018

ISTI/Geobit at the Seismic Instrumentation Technology Symposium 2018

Sid Hellman of ISTI, (the US distributor of GEObit instrumentation), is attending the IRIS Seismic Instrumentation Technology Symposium 2018 in Tucson, Arizona, October 30 to 31.

ISTI specializes in developing custom data acquisition, analysis, and processing software for the geophysical sciences. Microseismic data acquisition and processing are performed by custom solutions using existing open source software as a foundation, saving our customers both time and money. ISTI provides several products and services covering all geophysical applications and monitoring needs of the industry.

GEObit provides high sensitivity wide-band and near broad-band seismic sensors, surface or borehole type, and high dynamic range, low power 32bit ADC data loggers with local data storage and real-time telemetry over seedlink protocol. We are focusing on low power and cost-efficient solutions so we provide to our customer seismic networks with low installation and maintenance costs. Our instruments are ideal for local and regional seismicity and micro-seismicity monitoring and for seismic events such as those induced by unconventional hydrocarbon extraction. Our high fidelity data loggers ensure that these signals are recorded with the highest resolution and timing accuracy.

Please look for Sid to discuss GEObit, or anything else seismic related. 

Visit the Seismic Instrumentation Technology Symposium 2018 website for more information on this event.