T-shaped optical fiber branch cable array for long-baseline underwater acoustic positioning

Abstract

The invention relates to a T-shaped optical fiber branch cable array for long-baseline underwater acoustic positioning, which comprises a plurality of underwater acoustic positioners, the underwater acoustic positioners are connected with branch cables, the branch cables are connected with a main optical cable through optical cable splitters, and the main optical cable and the branch cables are deployed underwater according to a preset geometrical shape, so that the plurality of underwater acoustic positioners form a sonar array. Compared with a linear or annular sonar array, the long-baseline T-shaped optical fiber branch cable array for underwater acoustic positioning provided by the invention can prolong the service life and reduce the cost through maintenance.

Description

Technical Field

[0001] This application relates to underwater acoustic positioning equipment, and particularly to a T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning. Background Art

[0002] In related technologies, long baseline underwater acoustic positioning systems are widely used in fields such as marine exploration, underwater navigation, and underwater structure monitoring due to their high precision and large range coverage capabilities. Traditional long baseline underwater acoustic positioning systems usually adopt linear or circular sonar arrays, which have problems such as limited positioning accuracy, being easily buried by sediment during long-term deployment resulting in a significant reduction in received signal-to-noise ratio, and being difficult to repair after array failures in some application scenarios. Summary of the Invention

[0003] To overcome the problems existing in related technologies, this application provides a T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning.

[0004] The T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning includes a plurality of underwater acoustic positioners. The underwater acoustic positioners are connected to branch cables, and the branch cables are connected to the main optical cable through an optical cable splitter. The main optical cable and the branch cables are deployed underwater according to a predetermined geometric shape so that the plurality of underwater acoustic positioners form a sonar array.

[0005] In some exemplary embodiments of this application, based on the foregoing solution, a buoyancy ball is connected to the top of the underwater acoustic positioner, and the buoyancy of the buoyancy ball is used to pull up the underwater acoustic positioner and make the branch cable and the main optical cable form a T shape.

[0006] In some exemplary embodiments of this application, based on the foregoing solution, the buoyancy of the buoyancy ball pulls up the underwater acoustic positioner straight and keeps the optical cable splitter at the bottom of the water.

[0007] In some exemplary embodiments of this application, based on the foregoing solution, during use, the distance between the underwater acoustic positioner and the bottom of the water is greater than a preset size, and the preset size is adjusted according to the positioning frequency.

[0008] In some exemplary embodiments of this application, based on the foregoing solution, the underwater acoustic positioner is connected to the branch cable through a watertight junction box. Both ends of the watertight junction box are sealed by watertight O-rings, and a part of the repair optical fiber is pre-stored.

[0009] In some exemplary embodiments of this application, based on the foregoing solution, the branch cable and the main optical cable adopt the same type of optical cable.

[0010] In this application, multiple underwater acoustic locators are provided. The underwater acoustic locators are connected to branch cables, and the branch cables are connected to the main optical cable through an optical cable splitter. The main cable and the branch cables are deployed underwater in a predetermined geometric shape, so that the multiple underwater acoustic locators form a branch cable array. Compared with the traditional linear or circular sonar arrays, it is possible to control the laying operation to combine multiple single underwater acoustic locators into a sonar array according to a preset geometric shape, obtain a better positioning effect, and enable the long baseline underwater acoustic positioning system to increase its service life through maintenance and reduce costs.

[0011] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. Brief Description of the Drawings

[0012] The drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0013] Figure 1 is a schematic diagram of a T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning shown according to an exemplary embodiment. Detailed Embodiments

[0014] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the drawings in the embodiments of this application. Obviously, the described embodiments are some but not all of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts shall fall within the scope of protection of this application. It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily.

[0015] In the traditional technology, long baseline underwater acoustic positioning systems usually adopt linear or circular sonar arrays. During use, the sonar array is attached to the bottom of the water. During the positioning process of the underwater array elements, when receiving the positioning underwater acoustic signals emitted by the surface positioning sound source, the hydrophone elements receive multiple layers of reflected waves from the bottom of the water, resulting in overall pulse broadening and inaccurate delay measurement, which greatly restricts the effect of long baseline underwater acoustic positioning; in addition, after long-term operation, the underwater array elements are easily buried by sediment, the absorption loss increases, and the signal-to-noise ratio of the underwater array elements receiving signals is reduced; when the underwater array elements are damaged, the entire linear or circular sonar array needs to be fished out and the entire sonar array needs to be replaced, resulting in high maintenance costs.

[0016] To solve the problems existing in the existing long baseline underwater acoustic positioning system, this application provides a T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning.

[0017] Figure 1 It is a schematic diagram of a T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning shown according to an exemplary embodiment. Refer to Figure 1 , the T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning includes a plurality of underwater acoustic positioners. The underwater acoustic positioners are connected to branch cables, and the branch cables are connected to the main optical cable through an optical cable splitter. The main cable and the branch cables are deployed underwater according to a predetermined geometric shape so that a plurality of underwater acoustic positioners form a sonar array.

[0018] In this application, the T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning is composed of a plurality of underwater acoustic positioners. The number of underwater acoustic positioners is generally 4 sets, and can also be increased as needed. For example, when there is a need for array backup in the long baseline underwater acoustic positioning system, 5-6 sets of underwater acoustic positioners can be set. Four sets are used during operation, and the other 1-2 sets are used as backups. When a certain underwater acoustic positioner among the 4 sets in operation is damaged, the backup underwater acoustic positioner can be added to the array, thereby extending the service life of the system.

[0019] Each underwater acoustic positioner is connected to a branch cable, and the branch cable is connected to the main optical cable through an optical cable splitter.

[0020] The main optical cable and the branch cables are deployed underwater according to a predetermined geometric shape, and a plurality of underwater acoustic positioners form a branch cable array. Select appropriate laying points according to the water depth. According to the pre-compiled construction plan, strictly calculate the forward speed and cable laying speed of the cable laying ship, and lay the main optical cable and the branch cables at the laying points so that after a plurality of underwater acoustic positioners sink to the bottom, they present a predetermined geometric shape. For example, in this embodiment, 4 underwater acoustic positioners are made to present a square or a rectangle to achieve a good positioning effect.

[0021] In this embodiment, instead of using the traditional linear or circular sonar array, a plurality of single underwater acoustic positioners are combined into a sonar array by controlling the laying operation. On the one hand, the geometric shape of the array can be controlled according to actual needs to obtain a better positioning effect. On the other hand, when an individual underwater acoustic positioner is damaged, only the branch cable array needs to be retrieved from underwater, the damaged underwater acoustic positioner is replaced, and re-laid to realize the reuse of the underwater acoustic positioner and reduce the usage cost.

[0022] In an exemplary embodiment, a buoyancy ball is connected to the top of the underwater acoustic positioner, and the buoyancy of the buoyancy ball is used to pull up the underwater acoustic positioner and make the branch cable and the main optical cable form a T shape.

[0023] Utilize the buoyancy of the buoyancy ball to apply an upward buoyancy force to the top of the underwater acoustic locator, pull up the underwater acoustic locator, and make the branch cable and the main optical cable form a T shape, so that the underwater acoustic locator no longer adheres to the bottom of the water, weaken the Lloyd's mirror effect in underwater acoustics physics, improve the signal-to-noise ratio of the signals received by the underwater acoustic locator, and thus improve the positioning accuracy. Since the underwater acoustic locator is pulled up by the buoyancy ball and no longer adheres to the bottom of the water, the underwater acoustic locator will not be buried by sediment, which is beneficial to signal reception and avoids the problem that the underwater acoustic locator receives multiple reflected signals from the bottom of the water, resulting in signal broadening and a decrease in the signal-to-noise ratio after receiving and matching filtering.

[0024] In an exemplary embodiment, the buoyancy of the buoyancy ball pulls up the underwater acoustic locator straight and keeps the optical cable splitter at the bottom of the water.

[0025] In order to make the branch cable array present a better posture, it is necessary to select an appropriate diameter of the buoyancy ball according to the weight of the optical cable splitter. For example, in this embodiment, the weight of the splitter is more than 5 kg, and the diameter of the buoyancy ball is 15 cm. The buoyancy ball can provide sufficient buoyancy to pull up the underwater acoustic locator straight, but the optical cable splitter remains at the bottom of the water. On the one hand, the optical cable splitter realizes branching the branch cable from the main optical cable, and on the other hand, it plays a fastening role for the branch cable array, fixes the position of the underwater acoustic locator, and prevents the position of the branch cable array from deviating due to the action of water flow or other external forces.

[0026] In an exemplary embodiment, in the use state, the distance between the underwater acoustic locator and the bottom of the water is greater than a preset size, and the preset size is adjusted according to the positioning frequency.

[0027] By setting the length of the branch cable, when the buoyancy of the buoyancy ball pulls up the underwater acoustic locator straight, the distance between the underwater acoustic locator and the bottom of the water can be made greater than the preset size. For example, in a high-frequency positioning scenario, make the preset size 1 m to better apply to high-frequency positioning. In a low-frequency positioning scenario, make the preset size 1.5 m or larger to provide a better low-frequency positioning effect.

[0028] In an exemplary embodiment, the underwater acoustic locator is connected to the branch cable through a watertight junction box. Both ends of the watertight junction box are sealed by watertight O-rings, and some maintenance optical fibers are pre-stored.

[0029] For example, each underwater acoustic locator includes 2 - 4 array elements, the array element spacing is 0.25 mm, the outer diameter of the underwater acoustic locator is 27 mm; the diameter of the branch cable is 9 mm; the outer diameter of the watertight junction box is 27 mm, and the length is 100 mm. One end of the watertight junction box is connected to the underwater acoustic locator, and the other end is connected to the branch cable and sealed by a watertight O-ring. At the same time, some optical fibers are pre-stored in the space inside the watertight junction box. When the underwater acoustic locator is damaged and needs to be repaired, it can be connected according to the new underwater acoustic locator and using the pre-stored optical fibers, without having to replace the branch cable, improving the repair efficiency and reducing the repair cost.

[0030] In an exemplary embodiment, the branch cable and the main optical cable are of the same type of optical cable. For example, both the branch cable and the main optical cable use 18-core inner armored optical cables. After connecting the main optical cable and the branch cable through an optical cable splitter, since the outer sheath materials of the main optical cable and the branch cable are the same and the diameters are the same, it is easier to perform vulcanization treatment, and when using a cable reel to wind the cables, there is better consistency.

[0031] To better understand the T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning provided by this application, specific embodiments are used for illustration. Specific embodiment:

[0033] According to the positioning requirements, 4 underwater acoustic positioners are hermetically connected to one end of the branch cable through a watertight junction box. The other end of the branch cable is connected to the main optical cable through an optical cable splitter. Among them, the optical cable splitters of the first 3 underwater acoustic positioners split 4 optical fibers from the main optical cable, and the optical cable splitter of the 4th underwater acoustic positioner does not perform a splitting operation.

[0034] Wind the main optical cable and the branch cable connected with 4 underwater acoustic positioners on a cable reel, and use a cable laying ship to tow them to the laying site and select a suitable laying point.

[0035] During cable laying, tie the branch cable to the main optical cable with cable ties, hang a metal buckle on the top of the underwater acoustic positioner, and hang a buoyancy ball.

[0036] According to the pre-compiled construction plan, control the forward speed and cable release speed of the cable laying ship, and manually guide the buoyancy ball and the underwater acoustic positioner to be lowered into the water through a fairlead at the laying point.

[0037] The main optical cable and the optical cable splitter drive the branch cable, the underwater acoustic positioner and the buoyancy ball to sink into the water. Under the action of the buoyancy ball, the buoyancy of the buoyancy ball pulls the underwater acoustic positioner straight up. After laying is completed, the underwater branch cable and the main optical cable are in a T shape, and the distance between the underwater acoustic positioner and the bottom of the water is greater than 1 m. The 4 underwater acoustic positioners are arranged in a rectangle.

[0038] According to the above embodiments, the T-shaped fiber optic branch cable array for long baseline underwater acoustic positioning provided by this application can connect the underwater acoustic positioner to the main optical cable through the branch cable and the optical cable splitter, and during cable laying, deploy it according to a preset geometric shape so that multiple underwater acoustic positioners form a sonar array. It avoids the problem that the existing linear or circular sonar arrays cannot be repaired or replaced. At the same time, by using the buoyancy ball, the underwater acoustic positioner is pulled straight up, so as to be far away from the bottom of the water, avoid the underwater acoustic positioner being buried by sediment, reduce the Lloyd mirror effect, improve the signal-to-noise ratio, and thus improve the accuracy and service life of long baseline underwater acoustic positioning.

[0039] In this application, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that an article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such article or device. Without further limitation, an element defined by the statement "comprising..." does not preclude the presence of additional identical elements in the article or device comprising said element.

[0040] Although the preferred embodiments of this application have been described, those skilled in the art can make additional changes and modifications once they learn of the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0041] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, the intention of this application also includes these modifications and variations.

Claims

1. A T-type optical fiber branch cable array for long baseline hydroacoustic positioning, characterized in that: It comprises a plurality of hydroacoustic locators, the hydroacoustic locators are connected to branch cables, the branch cables are connected to the main optical cable through an optical cable brancher, the main optical cable and the branch cables are deployed underwater in a predetermined geometric shape, so that the plurality of hydroacoustic locators form a sonar array.

2. The T-type optical fiber branch cable array for long baseline hydroacoustic positioning according to claim 1, characterized in that: The top of the hydroacoustic locator is connected to a buoyancy ball, and the hydroacoustic locator is pulled up by utilizing the buoyancy of the buoyancy ball, and the branch cable and the main optical cable are formed into a T shape.

3. The T-type optical fiber branch cable array for long baseline hydroacoustic positioning according to claim 2, characterized in that: The buoyancy of the buoyancy ball pulls up the hydroacoustic locator straightly and keeps the optical cable branching device at the bottom of the water.

4. The T-type optical fiber branch cable array for long baseline hydroacoustic positioning according to claim 3, characterized in that: When in use, the distance between the hydroacoustic locator and the bottom of the water is greater than a preset size, and the preset size is adjusted according to the positioning frequency.

5. The T-type optical fiber branch cable array for long baseline hydroacoustic positioning according to claim 1, characterized in that: The hydroacoustic locator is connected to the branch cable through a watertight joint box. Both ends of the watertight joint box are sealed by watertight O-rings and a part of the repair optical fiber is pre-stored.

6. The T-type optical fiber branch cable array for long baseline hydroacoustic positioning according to claim 1, characterized in that: The branch cable and the main optical cable are the same type of optical cables.

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