METHODS AND SYSTEMS FOR NAVIGATING UNDER WATER
First Claim
1. A method for determining the absolute position under water of a submersible vessel having a dead reckoning navigation system not receiving position information from outside the vessel, where the vessel receives acoustic signals from a reference station having a known absolute position and calculates its range from the reference station, wherein said acoustic signals are received from the same reference station in several arbitrary positions of the vessel, and that estimated absolute positions of the vessel are calculated using sets of data, each set of data comprising said calculated range and navigation data from the dead reckoning navigation system, said navigation data being valid concurrently with said calculated range.
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Accused Products
Abstract
In a method for determining absolute position under water of a submersible vessel (1) having a dead recloning navigation system and receiving acoustic signals from a reference station (19), signals are received from one reference station in several positions (15-18) of the vessel. Estimated absolute positions of the vessel are calculated using range data and relative position data. Range rate data derived from the signals are preferably utilised. In a method for scanning an underwater survey area, the absolute position of a vessel (1) is intermittently being determined according to said method. The reference station may be placed at a fixed absolute position (19), or on the surface of the water, preferably in a buoy or a vessel. A system for determining the absolute position under water of vessel comprises: acoustic communication means in a reference station and on board the vessel; a dead reckoning navigation system on board the vessel; and computing means.
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Citations
65 Claims
- 1. A method for determining the absolute position under water of a submersible vessel having a dead reckoning navigation system not receiving position information from outside the vessel, where the vessel receives acoustic signals from a reference station having a known absolute position and calculates its range from the reference station, wherein said acoustic signals are received from the same reference station in several arbitrary positions of the vessel, and that estimated absolute positions of the vessel are calculated using sets of data, each set of data comprising said calculated range and navigation data from the dead reckoning navigation system, said navigation data being valid concurrently with said calculated range.
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19. A method for determining the absolute position under water of a submersible vessel having a dead reckoning navigation system not receiving position information from outside the vessel, where the vessel receives acoustic signals from a reference station having a known absolute position and calculates its range from the reference station, wherein said acoustic signals are received from one reference station in one or more positions of the vessel;
- wherein data for rate of change of the vessel'"'"'s range from the reference station (“
range rate data”
) are derived from said acoustic signals; and
wherein estimated absolute positions of the vessel are calculated using said calculated range, said range rate data, and navigation data from the dead reckoning navigation system. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 59, 60, 61, 62, 63, 64, 65)
- wherein data for rate of change of the vessel'"'"'s range from the reference station (“
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30. A method according to claim 30, wherein the absolute position of the reference station is determined by the submersible vessel at the surface of the water collecting absolute position data in a number of positions from a positioning system usable at the surface of the water, and while surfaced receiving acoustic signals from the reference station, and calculating range data from said signals, position and range data preferably being processed on board the vessel.
- 36. A method according to claim 36, wherein the reference station receives absolute position data from a positioning system usable at the surface of the water, and relays such data to the submersible vessel.
- 39. A method for scanning an underwater survey area by means of a submersible vessel traveling a desired path, the vessel having a dead reckoning navigation system not receiving position information from outside the vessel, where the vessel receives acoustic signals from a reference station having a known absolute position and calculates its range from the reference station, wherein the absolute position of the vessel is intermittently being determined.
Specification