Abstract: It is proposed a method for monitoring an electrical power supply line comprised in a seismic cable and extending along the seismic cable. The seismic cable includes: a plurality of seismic sensors arranged along the seismic cable, a plurality of controllers arranged along the seismic cable, and an optical transmission line extending along the seismic cable for carrying data signals from or towards the controllers. The electrical power supply line supplies at least one pair of master and slave controllers. The master controller of a given pair of master and slave controllers performs a step of monitoring a portion of the electrical power supply line between the master and slave controllers, by using an optical loop established on a portion of the optical transmission line between the master and slave controllers, and starting from the master controller and passing through the slave controller.

Abstract: A streamer for seismic prospection comprising directional sensors (20), such as geophones or accelerometers, distributed along the streamer, characterized in that said streamer comprises at least two tilt sensors (30, 40) located in remote positions and in locations distant from the directional sensors (20) and means which determined the effective orientation of each directional sensor (20) by interpolating along the streamer the tilt detected by the two tilt sensors (30, 40).

Abstract: It is proposed a method for monitoring an electrical power supply line comprised in a seismic cable and extending along the seismic cable. The seismic cable includes: a plurality of seismic sensors arranged along the seismic cable, a plurality of controllers arranged along the seismic cable, and an optical transmission line extending along the seismic cable for carrying data signals from or towards the controllers. The electrical power supply line supplies at least one pair of master and slave controllers. The master controller of a given pair of master and slave controllers performs a step of monitoring a portion of the electrical power supply line between the master and slave controllers, by using an optical loop established on a portion of the optical transmission line between the master and slave controllers, and starting from the master controller and passing through the slave controller.

Abstract: A streamer for seismic prospection comprising directional sensors (20), such as geophones or accelerometers, distributed along the streamer, characterized in that said streamer comprises at least two tilt sensors (30, 40) located in remote positions and in locations distant from the directional sensors (20) and means which determined the effective orientation of each directional sensor (20) by interpolating along the streamer the tilt detected by the two tilt sensors (30, 40).

Abstract: An apparatus and a method for multiplexing and demultiplexing Fiber Optic Interferometric Sensors (FOISs), including means for forming an optical source, at least one sensing cable, at least one wavelength demultiplexing system, and a calibration system.

Abstract: The invention deals with an apparatus and a method for multiplexing and demultiplexing Fiber Optic Interferometric Sensors (FOISs), said apparatus comprising: means (1) forming an optical source for providing l×n distinct trio (?qj, Fj, ?j) for the interferometric interrogation of l×n×m sensors, where for 1?j?p: ?qj is the frequency of the optical source 4qj (1?q?n/p), Fj is a RF frequency carrier generated upon the lights of the n/p emitters emitting at the frequency ?qj (1?q?n/p), and ?j is a time window where the light of the n/p emitters 4qj (1?q?n/p) are on, at least one sensing cable (100) comprising n groups of m fiber optic interferometric sensors each, and means for dedicating a unique given trio (?qj, Fj, ?j) to the interrogation of a unique group of m fiber optic interferometric sensors; at least one wavelength demultiplexing system (40) for separating the n frequencies ?qj (1?q?n/p and 1?j?p) into n/p outputs (33q for 1?q?n/p) containing respectively the lights of wavelength bands Bq for 1?q?n/