# CGG Marine chooses MIS for its seismic research vessels

December 2004 · Olex

> Through Cadden, CGG selects MIS to equip its seismic vessels with an Olex-based vessel tracking system for its project in India.

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Through [Cadden](http://www.cadden.fr), MIS was selected to equip the seismic research vessels of the Compagnie Générale de Géophysique with a vessel tracking system. The system is designed to secure the survey areas of its project in India with the oil company ONGC (Oil and Natural Gas Corp, which produces 80% of India's oil).

MIS carried out the custom development of a VTS (transponder-based Vessel Tracking System) based on the Olex software and the Thales [Tracs TDMA](/images/TracsTDMA_Datasheet.pdf) hardware solution, which includes a GPS receiver and is distributed by Cadden.

TDMA is a digital transmission technology that lets several users share a single-frequency radio channel without interference, by assigning each of them unique time slots. The position of each mobile unit is transmitted over VHF every second. The limited range of VHF is extended by a relay technique: each TDMA mobile acts as a dynamic repeater, creating a network between all the mobiles.

Installed on 5 vessels, including the CGG seismic vessels “Alizé”, “Foehn” and “Symphony”, the software secures the sites by [displaying](/images/CGG.png) and recording the tracks of some forty guard boats and chase boats sailing around the seismic survey vessels.

An interface was also developed with Spectra, the Linux software from Concept Systems dedicated to the navigation of seismic research vessels, to send it the positions of the mobiles displayed in Olex.

[Press release](/images/Hydro_press_release.jpg)

*About [CGG](http://www.cgg.com), in 2004: the Compagnie Générale de Géophysique is one of the world leaders in geophysical services. Its activities cover seismic data acquisition as well as reservoir processing and interpretation services and software for oil companies. CGG is also the world's leading manufacturer of geophysical equipment, through its subsidiary Sercel.*