How does it work

The system: how does it work?


The beacons send a signal to the satellites at regular time intervals.



The satellites collect the data (signal = GPS position + pre-coded messages). Satellites flying over the Earth receive the signal, record it on board and then re-transmit it in real-time to direct receiving stations.


The receiving stations relay the signal between the satellites and the processing centres. More than 80 ground receiving antenna are installed on the Globe.


The data processing centres gather all the data, before processing it and distributing it to users. CLS has three processing centres with redundant operation: the first at the CLS Head Office in Toulouse, the second at CNES in Toulouse on CLS’s head office  and the third in the USA near Washington DC – thus providing continuous operation whatever situations may arise. Once the data has reached the processing centre, the locations are automatically calculated and made available to the users.


a service H24 365 day/year

a carefully support

Since more than 20 years, CLS manage his specialists who provide operational monitoring of all races and adventures throughout the year for optimum service

An operational center H24

A team of operators and system engineers constantly monitors the messages transmitted by the tags thereby improving the safety of sailors and adventurers.

A distribution of information tailored

The locations are sent by email, fax, ftp or available on CLS Server (protected access).
The locations are accessible on base map from:

  • Following a mapping software Themis,
  • cartographic software installed on your PC
  • data distribution site CLS (GoogleEarth projection possible)