Sonardyne International Limited

Christopher D Pearce

Richard J Smith

Roger Sydney Dudley Smith, Legal Representative

David Lawes

Mikael Larsen

Shaun Dunn

Judith Jane Smith, Legal Representative

A subsea measurement system () comprises a first reference beacon () disposed at a first known location, a second reference beacon () disposed at a second known location, and an acoustic communications module () for coupling to a subsea element to be monitored. The acoustic communications module () is capable of moving, when in use, relative to the first reference beacon () and the second reference beacon (). The acoustic communications module () also comprises a processing resource and is arranged to determine first range-related data to the first reference beacon () in response to receipt of a first signal by the acoustic communications module () from the first reference beacon () and second range-related data to the second reference beacon () in response to receipt by the acoustic communication module () of a second signal from the second reference beacon ().

Subsea measurement system and method of determining a subsea location-related parameter

A data collection systemfor estimating a corrected sound speed between a first point and a second point comprises a subsea acoustic transponder beacon () disposed at a fixed position relative to a seabed (), and an acoustic transceiver () immersed below a sea surface () and above the acoustic beacon (). A processing resource () is also operably coupled to the acoustic transponder (), the acoustic transceiver () being arranged to traverse a path above the acoustic beacon () and communicate with the acoustic beacon (). The processing resource () is also arranged to collect time-of-flight data associated with the communication between the acoustic transceiver () and the acoustic beacon ().

Data collection system, marine seismic survey system and method of estimating a corrected sound speed

A system and method measures the time offsets of a plurality of acoustic sensor nodes relative to a reference time. The system includes an acoustic transceiver arranged to transmit a first signal to each acoustic sensor node and a processing resource arranged to record the transmission time of the first signal relative to the reference time. The acoustic sensor nodes receive the first signal and transmit a return second signal to the acoustic transceiver after a predetermined time delay, the second signal including the current acoustic sensor node internal time. The acoustic transceiver receives the second signal, and the processing resource records the time at which the second signal was received relative to the reference time and records also the combined time of flight of the first and second signal. From this data the time offset between the sensor node internal time and the reference time is calculated.

System for measuring a time offset and method of measuring a time offset

A robust underwater communication system, for communication between an acoustic signal transmitter and a remotely positioned acoustic signal receiver, wherein transmitted data is carried by a plurality of symbols each having two components one of which comprises a distinctive bit code and the other of which appertains to the character of the symbol as a whole wherein the character of successive symbols is stepped through a predetermined continuously repeating sequence of distinctive steps each of which occurs once in the sequence, the signal receiver being operated synchronously with the signal transmitter and comprising a correlator arrangement responsive both to the bit code and to the character of received signals for effecting demodulation and having a plurality of outputs one for each symbol, so that as each symbol is detected a signal on the output to which it corresponds pre-dominates and amplitude detector means responsive to the outputs from the correlator arrangement for providing an output signal corresponding to the data transmitted.

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Hook, United Kingdom

Christopher D Pearce