Telemetering acoustic method for determining the relative position of a submerged object with respect to a vehicle and device therefor
First Claim
1. An acoustic telemetry method for determining the position of an object submerged at great depth with respect to a ship towing the object at the end of a cable, the method comprising:
- (a) transmitting acoustic pulses, each from one of at least three different emission locations of the ship, in a manner such that the displacement of the ship during the transmission time is substantially negligible and in a manner such that after propagation of the pulses to the object, said acoustic pulses can be discriminated from one another;
(b) receiving the emitted pulses at a reception location on the submerged object;
(c) measuring on the submerged object the respective propagation times of the emitted pulses from time of transmission to time of reception;
(d) digitizing the measured values to provide data in digitized form;
(e) transmitting the digitized data to the ship, through said cable; and
(f) combining, on board the ship, the different measured values forming said transmitted digitized data, the values of the distances between the emission locations and the values of the time intervals between the transmitted pulses, and determining therefrom in a predetermined manner the coordinates of the submerged object with respect to the ship.
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Accused Products
Abstract
The position of a submerged object towed at great depth from a ship is determined, with respect to the ship, from measured values of the travel time of acoustic pulses between the ship and the object. These pulses are emitted at different locations of the ship and received at a point of the object. The values of the travel times of the pulses are measured and digitized on the object and transmitted by cable to the ship where they are processed, in combination with values representing the distances between the emission locations, to determine the coordinates of the object with respect to a system of axes associated with the ship.
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Citations
13 Claims
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1. An acoustic telemetry method for determining the position of an object submerged at great depth with respect to a ship towing the object at the end of a cable, the method comprising:
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(a) transmitting acoustic pulses, each from one of at least three different emission locations of the ship, in a manner such that the displacement of the ship during the transmission time is substantially negligible and in a manner such that after propagation of the pulses to the object, said acoustic pulses can be discriminated from one another; (b) receiving the emitted pulses at a reception location on the submerged object; (c) measuring on the submerged object the respective propagation times of the emitted pulses from time of transmission to time of reception; (d) digitizing the measured values to provide data in digitized form; (e) transmitting the digitized data to the ship, through said cable; and (f) combining, on board the ship, the different measured values forming said transmitted digitized data, the values of the distances between the emission locations and the values of the time intervals between the transmitted pulses, and determining therefrom in a predetermined manner the coordinates of the submerged object with respect to the ship. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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- 9. An apparatus for determining the position of a submerged object with respect to a ship towing the object at the end of a cable, said apparatus comprising emission means for emitting acoustic pulses from at least three different locations of the ship, pulse generating means located on the ship for generating a sequence of pulses of the same duration and of the same frequency with a time interval therebetween, means for transmitting said pulses to the respective emission means for emission therefrom, receiving means on the submerged object for receiving the emitted acoustic pulses, computation means on board of the ship for computing coordinates of the object with respect to the ship, clock means located in the submerged object for generating a signal defining a time scale for controlling the pulse generating means, timing means and phase-shift measuring means with said object for measuring the propagation time of the different emitted acoustic pulses of the sequence in relation to the period of the signal generated by the clock means, depth measuring means with said object for measuring the depth in the water of the object, the depth means incorporating digitization means operative for digitizing the measuring values by making use of the signal generated by the clock, and trasmission means for transmitting the measured values in digitized form from the submerged object to the computation means on board the ship for computing the position of the object.
Specification