| 摘要 |
A system and method for determining the position of towed marine object relative to a towing vessel. The system comprises a towing vessel, a slave vessel, and the towed object. An acoustic transceiver is located on either the towing vessel or the slave vessel with an acoustic receiver located on the other vessel. One or more acoustic transponders are associated with the towed object. The distance between the towing vessel and the slave vessel is determined, for example, by radio navigation which is calibrated by a high precision range-range system. The acoustic transmitter emits an interrogation signal which causes the transducer(s) to emit a response acoustic signal which is recorded at the two receivers. Using the time for the response signal to reach each of the receivers and the velocity of sound in water, the distance of the transducer from each vessel is calculated. With the three distances the location of the transducer relative to the towing vessel is determined by trilateration. The system is especially useful for determining the horizontal profile of a towed seismic cable, where a series of transducers are located along the cable. The interrogation signal will interrogate each transducer sequentially and by trilateration of each transducer a very accurate representation of the horizontal profile is obtained.
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