Tension monitoring method and system for towed antenna

A computing device for calculating a tension (T) in a towed antenna, the computing device comprising:

• an interface for receiving recordings from plural particle motion sensors distributed along the antenna, wherein the recordings are indicative of transverse vibrations that propagate along the antenna;
• and
• a processing unit connected to the interface and configured to,
• calculate a value of a phase velocity (vp) of the transverse vibrations that propagate along the antenna based on (1) an offset between two particle motion sensors and (2) a time delay of the transverse vibrations that propagate from one of the two particle motion sensors to another one of the two particle motion sensors;
• select a relation that links the phase velocity (vp) to the tension (T);
• and
• use the value of the phase velocity and the relation to determine the tension (T) at various locations of the plural particle motion sensors along the antenna.

A streamer to be towed in water for collecting seismic data, the streamer comprising:

• a body;
• plural particle motion sensors located inside the body;
• and
• a computing device located inside the body, the computing device including,
• an interface for receiving recordings from the plural particle motion sensors, wherein the recordings are indicative of transverse vibrations that propagate along the streamer, and
• a processing unit connected to the interface and configured to,
• calculate a value of a phase velocity (vp) of the transverse vibrations that propagate along the streamer based on (1) an offset between two particle motion sensors and (2) a time delay of the transverse vibrations that propagate from one of the two particle motion sensors to another one of the two particle motion sensors;
• select a relation that links the phase velocity (vp) to the tension (T);
• and
• use the value of the phase velocity and the relation to determine the tension (T) at various locations of the plural particle motion sensors along the antenna.