Triplet acoustic ring assembly and nested array

Abstract

The ring assembly of the underwater acoustic sensor (hydrophone) system includes a ring with brackets for mounting hydrophones evenly spaced circumferentially. The ring assembly may have three hydrophones mounted on the ring, maintaining the hydrophones in a triplet configuration. Multiple ring assemblies may be stacked in a nested array, with the hydrophones of adjacent stacked ring assemblies offset circumferentially, each hydrophone overlapping multiple of the stacked rings, and the stacking achieved such that the ring assemblies form a spiral array. Rings with non-acoustic sensors may be stacked with (and interspersed within) stacked rings. The stacked array of ring assemblies (and non-acoustic sensor assemblies) may be stored in a canister that facilitates uniform and controlled lowering and deployment of the assemblies, with the ring assemblies and non-acoustic assemblies being sequentially paid out from the float at the top of the array.

Description

[Technical Field]

[0001] TECHNICAL FIELD This disclosure is in the field of underwater acoustic (hydrophone) arrays. [Background technology]

[0002] Sensor arrays may be used in a variety of applications. Exemplary sensor arrays include hydrophone arrays. Hydrophone arrays may be implemented in sonobuoys dropped or pushed from aircraft, ships, or land vehicles. Arrays may be dropped into environments for surveillance. For example, sensor arrays may be dropped into the ocean for underwater acoustic surveys. Sonobuoys housing hydrophone arrays may be used in military applications such as anti-submarine warfare. Sonobuoys typically have small sizes, and as a result, packing a hydrophone line array into a sonobuoy presents challenges.

[0003] To obtain the azimuth and range of undersea acoustic targets using classical sonar processing methods, vertical and horizontal hydrophone arrays are required. Detecting low source levels and / or low frequency sources requires large aperture (long length) arrays. Deploying both vertical and horizontal arrays is mechanically challenging and often power consuming. Summary of the Invention

[0004] The triplet ring assembly includes three acoustic sensors or hydrophones circumferentially spaced around the ring.

[0005] The hydrophone array includes ring assemblies stacked together, and the stacks may have hydrophones in a spiral configuration.

[0006] The deployable array comprises a ring assembly of hydrophones that are sequentially deployed from a canister to create a cylindrical array.

[0007] According to an aspect of the present disclosure, a hydrophone assembly includes a ring and hydrophones mounted on the ring at evenly spaced intervals around the circumference of the ring.

[0008] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring includes ring segments separating brackets that receive the hydrophones.

[0009] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring segments define gaps between them for receiving cables of an assembly coupled to each of the hydrophones.

[0010] According to an embodiment of any paragraph(s) of this Summary of the Invention, the hydrophone assembly includes three hydrophones circumferentially spaced around a ring to form a triplet array.

[0011] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring is made of metal.

[0012] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring is made of plastic.

[0013] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring is additively manufactured.

[0014] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring is a single, continuous, integral piece of material.

[0015] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring assembly is part of an array pack that includes additional ring assemblies operatively coupled together.

[0016] According to an embodiment of any paragraph(s) of this Summary of the Invention, all of the ring assemblies are substantially identical in construction.

[0017] According to an embodiment of any paragraph(s) of this Summary of the Invention, adjacent rings of the ring assembly are in contact.

[0018] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring assemblies of the array pack are stored in a nested configuration prior to deployment.

[0019] According to an embodiment of any paragraph(s) of this Summary of the Invention, the cables extending between the ring assemblies are radially inward of the rings of the ring assemblies when the ring assemblies are in a nested configuration.

[0020] According to an embodiment of any paragraph(s) of this Summary of the Invention, when the ring assemblies are in a nested configuration, the cables are in a flood area of ​​the array, the flood area being defined by the rings of the ring assemblies.

[0021] According to an embodiment of any paragraph(s) of this Summary of the Invention, the flood region is in fluid communication with the gap in the ring.

[0022] According to an embodiment of any paragraph(s) of this Summary of the Invention, adjacent ring assemblies are stacked such that a hydrophone of a first ring assembly of an adjacent ring assembly radially overlaps a ring of a second ring assembly of the adjacent ring assembly, and the hydrophone of the first ring assembly is circumferentially offset from the hydrophone of the second ring assembly.

[0023] According to an embodiment of any paragraph(s) of this Summary of the Invention, the rings are stacked in a spiral fashion.

[0024] According to an embodiment of any paragraph(s) of this Summary of the Invention, the device further includes a non-acoustic sensor assembly between some adjacent pairs of the ring assemblies.

[0025] According to an embodiment of any paragraph(s) of this Summary of the Invention, each of the non-acoustic sensor assemblies includes one or more non-acoustic sensors.

[0026] According to an embodiment of any paragraph(s) of this Summary of the Invention, the one or more non-acoustic sensors include one or more of a pressure sensor, a temperature sensor, a salinity sensor, a position sensor, an orientation sensor, a roll sensor, a pitch sensor, and / or a heading sensor.

[0027] According to an embodiment of any paragraph(s) of this Summary of the Invention, the non-acoustic sensor assemblies each include a non-acoustic sensor assembly ring to which one or more non-acoustic sensors are attached.

[0028] According to an embodiment of any paragraph or paragraphs of this Summary of the Invention, each of the non-acoustic sensor assemblies includes a centrally located non-acoustic sensor of the one or more non-acoustic sensors, the centrally located non-acoustic sensor being positioned along a central axis of the non-acoustic sensor assembly ring at an intersection of arms extending radially inward from the non-acoustic sensor assembly ring.

[0029] According to an embodiment of any paragraph(s) of this Summary of the Invention, each of the non-acoustic sensor assemblies includes three of the arms extending radially inward from the non-acoustic sensor assembly ring.

[0030] According to an embodiment of any paragraph(s) of this Summary of the Invention, for each of the non-acoustic sensor assemblies, the centrally located non-acoustic sensor is one or more non-acoustic sensors, and the non-acoustic sensor assembly does not otherwise include any other non-acoustic sensors.

[0031] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring assemblies are triplet ring assemblies, each comprising three acoustic sensors.

[0032] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring assemblies are coupled together by a cable.

[0033] According to an embodiment of any paragraph(s) of this Summary of the Invention, the cable is at least 3 m (10 ft) long and, when deployed, the ring assemblies are separated by at least 3 m (10 ft).

[0034] According to an embodiment of any paragraph(s) of this Summary of the Invention, the device further includes a canister in which the array pack resides prior to deployment and partially during deployment.

[0035] According to an embodiment of any paragraph(s) of this Summary of the Invention, the device further includes a lower electronics unit coupled to the array pack.

[0036] According to an embodiment of any paragraph(s) of this Summary of the Invention, the device further includes an upper assembly coupled to the lower electronics unit by the array reader.

[0037] According to an embodiment of any paragraph(s) of this Summary of the Invention, the upper assembly is a float assembly capable of floating.

[0038] According to an embodiment of any paragraph(s) of this Summary of the Invention, the lower electronics unit includes hardware and / or software, such as a node card, for recording, integrating, manipulating, and / or interpreting data from acoustic and / or non-acoustic sensors.

[0039] According to an embodiment of any paragraph(s) of this Summary of the Invention, the lower electronics unit includes a transmitter.

[0040] According to another aspect, a hydrophone array pack unit includes an upper assembly, a canister mechanically releasably coupled to the upper assembly, and an array pack within the canister, the array pack including a nested ring assembly deployable by vertical separation.

[0041] According to an embodiment of any paragraph(s) of this Summary of the Invention, the upper assembly includes an upper assembly electronics unit.

[0042] According to an embodiment of any paragraph(s) of this Summary of the Invention, the upper assembly includes a battery system.

[0043] According to an embodiment of any paragraph(s) of this Summary of the Invention, the upper assembly is a float assembly capable of floating on water.

[0044] According to an embodiment of any paragraph(s) of this Summary of the Invention, the canister and array pack are heavier than water and are separated from the upper assembly when the mechanical coupling between the upper assembly and the canister is released.

[0045] According to an embodiment of any paragraph(s) of this Summary of the Invention, when the mechanical coupling is released, the array pack remains tethered to the upper assembly by the array reader.

[0046] According to an embodiment of any paragraph(s) of this Summary of the Invention, separation of the canister from the upper assembly autonomously triggers deployment of the ring assemblies from the canister, the ring assemblies being vertically separated from one another, and the cables being attached to the ring assemblies while the ring assemblies are separated.

[0047] According to an embodiment of any paragraph(s) of this Summary of the Invention, the ring assemblies are triplet ring assemblies, each having three acoustic sensors mounted on the ring, the acoustic sensors being evenly spaced circumferentially around the ring.

[0048] According to yet another aspect, a method of deploying a hydrophone array includes mechanically releasing a canister from a float assembly, the canister including an array pack of nested stacked ring assemblies, each ring assembly including a ring and a plurality of hydrophones attached to and circumferentially spaced around the ring; and deploying the ring assemblies from the canister while the canister is moving away from the float assembly, the ring assemblies remaining tethered to each other and to the float assembly during deployment.

[0049] According to an embodiment of any paragraph(s) of this Summary of the Invention, the deploying includes sequentially deploying the ring assemblies from the canister.

[0050] According to an embodiment of any paragraph(s) of this Summary of the Invention, the deploying includes deploying the ring assemblies from the canister in spaced-apart relation to one another.

[0051] According to an embodiment of any paragraph(s) of this Summary of the Invention, the deploying includes deploying the ring assemblies from the canister while a cable connecting adjacent ones of the ring assemblies is unwound.

[0052] According to an embodiment of any paragraph(s) of this Summary, the method further includes separating the canister from the ring assemblies and the float assembly after all of the ring assemblies have been deployed from the canister, such that the canister is no longer mechanically connected to either the ring assemblies or the float assembly.

[0053] Although certain features are described herein with respect to embodiments of the present disclosure, features described with respect to a given embodiment may also be used in connection with other embodiments. The following description and accompanying set of drawings set forth certain exemplary embodiments of the present disclosure. However, these embodiments are indicative of only a few of the various ways in which the principles of the present disclosure may be employed. Other objects, advantages, and novel features according to aspects of the present disclosure will become apparent from the following detailed description when considered in conjunction with the drawings.

[0054] The accompanying drawings, which are not necessarily to scale, depict various aspects of the present disclosure. [Brief explanation of the drawings]

[0055] [Figure 1] FIG. 1 is a perspective view of a triplet acoustic array ring assembly, according to an embodiment. [Figure 2] FIG. 2 is a plan view of the ring assembly of FIG. 1. [Figure 3] FIG. 1 is a perspective view of an array pack including nested triplet acoustic ring assemblies, according to an embodiment. [Figure 4] FIG. 4 is a side view of the array pack of FIG. 3. [Figure 5] FIG. 4 is a perspective view of a deployment system including the array pack of FIG. 3, according to an embodiment. [Figure 6] FIG. 6 is a side view of the deployment system of FIG. 5. [Figure 7] 6 is a high-level flowchart of a deployment method for the deployment system of FIG. 5, according to an embodiment. [Figure 8] FIG. 8 is a side view of deployment according to the first step of the method of FIG. 7. [Figure 9] FIG. 8 is a side view of deployment according to a second step of the method of FIG. 7. [Figure 10] FIG. 8 is a side view of deployment according to a third step of the method of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0056] The ring assembly of the underwater acoustic sensor (hydrophone) system includes a ring with brackets for mounting hydrophones evenly spaced circumferentially. The ring assembly may have three hydrophones mounted on the ring, maintaining the hydrophones in a triplet configuration. The ring may have slots or gaps for routing cables connected to the hydrophones. Multiple ring assemblies may be stacked in a nested array, with the hydrophones of adjacent stacked ring assemblies offset circumferentially, each hydrophone overlapping multiple of the stacked rings, and the stacking achieved so that the ring assemblies form a spiral array. Rings with non-acoustic sensors may be stacked with (and interspersed within) the stacked rings. The stacked array of ring assemblies (and non-acoustic sensor assemblies) may be stored in a canister that facilitates uniform and controlled lowering and deployment of the assemblies, and the ring assemblies and non-acoustic assemblies are sequentially paid out from the float at the top of the array. Following deployment of the assembly, the canister (or can) is removed from the bottom of the deployed array (structure), thereby maintaining the thin profile of the deployed array and reducing drag from cross-flow.

[0057] This configuration allows for volumetric efficiency prior to deployment and allows for reliable autonomous deployment of multiple ring assemblies of the system, such as by using gravity to separate the ring assemblies from one another. Additionally, the rings maintain the desired configuration of sensors (hydrophones) at the individual nodes of the system, for example, a desired triplet configuration of three hydrophones evenly spaced circumferentially around the ring.

[0058] 1 and 2 show a ring assembly 10 including a ring 12 and three acoustic sensors (hydrophones) 14, 16, and 18 evenly spaced around the circumference of the ring 12. The ring 12 includes three brackets 24, 26, and 28 for receiving the hydrophones 14, 16, and 18, respectively. The brackets 24, 26, and 28 are held in a spaced triplet configuration by a series of ring segments 32, 34, and 36, which together define the annular shape of the ring 12. The ring segments 32-36 leave gaps 44, 46, and 48 in the brackets 24-28 to allow the passage of cables 54, 56, and 58, the ends of which are shown in FIGS.

[0059] The ring 12 may be made of any of a variety of suitable materials, such as, for example, metal or plastic. The ring 12 may be a single continuous, integrated piece of material, for example, additively manufactured.

[0060] The ring assembly 10 is shown with three acoustic sensors 14-18 arranged in a triplet configuration. Such a configuration has desirable inter-sensor spacing maintained by the ring 12, allowing, for example, the formation of a steerable cardioid beam 60, providing direction. This is in contrast to a single omnidirectional hydrophone, which provides no directionality when used alone.

[0061] The configuration of the triplet arrangement produced by the ring assembly 10 may be adjusted for detection of sources at various source levels and frequencies. Additionally, different numbers of acoustic sensors may be used in the ring assembly.

[0062] 3 and 4, an array pack 100 of stacked ring assemblies 10 is shown. The ring assemblies 10 may all be substantially identical in configuration; that is, they may not be exact replicas of one another, but they may have the same overall layout. The ring assemblies 10 of the array pack are stacked in a spiral arrangement, with the acoustic sensors of adjacent ones of the ring assemblies being continuously offset in the circumferential direction 102. This allows the ring assemblies 10 to be stacked in a nested arrangement, with the acoustic sensors of individual ring assemblies of the ring assembly 10 radially overlapping the rings of adjacent (axially stacked) ring assemblies without interference between the acoustic sensors of adjacent ring assemblies of the ring assemblies due to the circumferential offset of the sensors in the spiral arrangement.

[0063] Prior to deployment, the cables of the ring assembly 10 are stored in a free flood area 108 within the array pack 100. The flood area 108 is an area that is filled with water as part of the deployment process, such as before the ring assembly 10 is deployed from the stacked, nested, or spiral arrangement shown in FIGS. 3 and 4 . The flood area 108 is defined by the interior portions of the rings 12 ( FIG. 1 ) of the ring assembly 10. The flood area 108 is also in fluid communication with the gaps 44-48 ( FIG. 2 ) in the rings 12. This allows the cables 54-58 ( FIG. 2 ) to freely enter the flood area 108 through the gaps, allowing the rings 12 of the ring assembly to be stacked directly without interfering with the placement of the cables.

[0064] It should be understood that only a small portion of the cable is shown in Figures 1-4. The actual cable is long enough to extend between adjacent ring assemblies of ring assembly 10 when the system is fully deployed, as further described below. The cables may be packed within flood area 108 in any suitable manner to allow for deployment without interfering with each other during deployment of the system.

[0065] Non-acoustic sensor assemblies 110 are also included in the array pack 100. The non-acoustic sensor assemblies 110 may be spaced intermittently within the ring assembly 10 and may be located at the top and / or bottom of the stack of nested assemblies 10 and 110.

[0066] In one embodiment, each non-acoustic sensor assembly 110 includes a ring 112 with arms 114, 116, and 118 extending inwardly from the ring 112. The arms 114-118 intersect at a central mount 120, to which a non-acoustic sensor (NAS) 122 is attached. The ring 112, arms 114-118, and mount 120 may be made from any of a variety of suitable materials, such as metal or plastic. The NAS 122 may be a sensor for reporting any of a variety of types of information, such as pressure, temperature, salinity, roll, pitch, and / or heading.

[0067] In the illustrated embodiment, there are 32 ring assemblies 10 and 5 non-acoustic sensor assemblies 110. A non-acoustic sensor assembly is located at the top and bottom of the stack for every eighth ring assembly 10. It should be understood that this is just one example and many other arrangements are possible.

[0068] The array 100 may have a height of about 30-40 cm, to give a range of non-limiting examples. The array may have a diameter of about 40 cm. Many other sizes are possible.

[0069] The puck array 100 may be integrated into a host vehicle, e.g., an aquatic vehicle such as a ship or underwater vehicle, or a test platform. The integrated array 100 may reside in a canister or canister before and during deployment. Such a canister or canister is shown in Figures 5 and 6 and will be described with respect to that embodiment.

[0070] As an alternative to directly integrating the puck array 100 with a host vehicle or platform, the array 100 may be integrated into a stand-alone hydrophone unit 200, as shown in Figures 5 and 6. The stand-alone unit 200 may be launched from an aircraft or water vehicle, etc., and then deployed autonomously.

[0071] In unit 200, stacked array 100 is disposed in a canister or canister 202. A similar canister or canister may be part of array 100 when integrated into a host vehicle or platform, as described above. Canister 202 may be made of aluminum or another suitable material. In Figures 5 and 6, canister 202 is shown as transparent for illustrative purposes.

[0072] As part of unit 200, canister 202 couples to an upper (float) assembly 212. Upper assembly 212 may include a float, a battery system for powering sensors in unit 200, and an upper electronics assembly. As described further below, the array reader and lower electronics assembly may be releasable from upper assembly 212 during the deployment process.

[0073] Figure 7 shows a high level flow chart of a method 300 for deploying a unit 200. Figures 8-10 show the steps of deployment.

[0074] In step 302, as shown in FIG. 8 , the array pack 100 is lowered from the upper float assembly 212. At this point, and until the deployment process is complete, the array 100 remains within the canister 202. The descent of the array pack 100 (and canister 202) may be by gravity, while the upper assembly 212 remains in place at or near the water surface due to buoyancy. The initial descent may include the extension of the array reader 222 from the top of the descending array pack 100 and canister 202 combination. The array reader 222 may be initially stored in the canister 202 and is coupled to the lower electronics unit 224, which initially descends with the array pack 100 and canister 202.

[0075] The lower electronics unit 224 may include a release mechanism that initially releases the canister 202 from the upper float assembly 212. Any of a variety of suitable mechanical release mechanisms may be used. The release may be automatic or may be triggered by any of a variety of events, including optional remote communication.

[0076] The lower electronics unit (LEU) 224 may also include hardware and / or software, such as node cards, for recording, integrating, manipulating, and / or interpreting data from acoustic and non-acoustic sensors. A transmitter for transmitting signals, such as data or database signals, may also be part of the lower electronics unit 224.

[0077] 9, after the array reader 222 is deployed, the LEU 224 and top NAS assembly 110 are withdrawn from the lowering canister 200 in step 306. This begins the process of deploying the assembly of the array 100.

[0078] Then, in step 310, the ring assemblies (nodes) 10 are withdrawn from the canister 202, followed by the NAS assemblies 110. The cables 250 between adjacent assemblies are unwound, and then the topmost assembly remaining in the canister 202 is withdrawn from the canister. When the assemblies are deployed, the vertical distance between adjacent assemblies may be approximately 6 m (20 ft). More broadly, the vertical distance may be at least 3 m (10 ft). These distances are non-limiting examples, and a wide variety of other distances may be used, depending on the circumstances.

[0079] Finally, in step 314, after the array 100 bottoms out, the canister 202 (which may include end weights) drops out from the bottom of the array 100. This helps reduce drag from crossflow on the deployed array 100.

[0080] The resulting deployed array is a vertical array of nodes such as triplet ring assemblies that form a cylindrical volume array in the water column. Each triplet ring assembly allows the vertical array to form a carotid shape that allows collection of both azimuth and range of low frequency, low sound level sources without the need for a secondary horizontal array.

[0081] Additionally, the triplet configuration allows for beam steering in the vertical and horizontal planes, allowing beam nulls to be aimed at sources of acoustic interference, providing processing gain during the execution of very quiet sources in potentially noisy environments.

[0082] Additionally, intermittent deployment of non-acoustic sensors within the volumetric array may be useful, for example, which may provide feedback on the array geometry when crossflow is present.

[0083] Systems such as those described herein can be easily reconfigured for different environments or for different scenarios, and therefore, they may be deployed in multiple locations across a variety of environments.

[0084] While the present disclosure has been illustrated and described with respect to one or more specific embodiments, equivalent alterations and modifications will occur to those skilled in the art upon reading and understanding this specification and the accompanying drawings. In particular, with respect to the various functions performed by the aforementioned elements (components, assemblies, devices, compositions, etc.), the terms used to describe such elements (including references to "means") are intended, unless otherwise indicated, to correspond to any element that performs the specified function of the described element (i.e., is functionally equivalent), even if it is not structurally equivalent to a structure of the present disclosure that performs that function in one or more exemplary embodiments of the present disclosure shown herein. Furthermore, while particular features of the present disclosure may be described above only with respect to one or more of the several illustrated embodiments, such features may be combined with one or more other features of other embodiments, as may be desirable or advantageous in any given or particular application.

Claims

1. Ring and and hydrophones mounted on the ring at equal intervals around the circumference of the ring.

1. A hydrophone assembly comprising: the ring includes ring segments separating brackets that receive the hydrophones; the ring segments define gaps therebetween for receiving cables of the hydrophone assembly coupled to each of the hydrophones; Hydrophone assembly.

2. The hydrophone assembly of claim 1 , wherein the hydrophone assembly includes three hydrophones circumferentially spaced around the ring to form a triplet array.

3. 10. The hydrophone assembly of claim 1, wherein the ring assembly is part of an array pack that includes additional ring assemblies operatively coupled together.

4. The hydrophone assembly of claim 3 , wherein the ring assemblies of the array pack are stored in a nested configuration prior to deployment.

5. 5. The hydrophone assembly of claim 4, wherein the cables extending between the ring assemblies are radially inward of the rings of the ring assemblies when the ring assemblies are in the nested configuration.

6. The hydrophone assembly of claim 5 , wherein the cable is in a flood area of ​​the array pack when the ring assembly is in the nested configuration, the flood area being defined by the rings of the ring assembly.

7. 5. The hydrophone assembly of claim 4, wherein adjacent ring assemblies are stacked such that a hydrophone of a first ring assembly of the adjacent ring assembly radially overlaps a ring of a second ring assembly of the adjacent ring assembly, and the hydrophone of the first ring assembly is circumferentially offset from the hydrophone of the second ring assembly.

8. The hydrophone assembly of claim 4 , wherein the ring assemblies are stacked in a helical array.

9. The hydrophone assembly of claim 4 further comprising a non-acoustic sensor assembly between some adjacent pairs of said ring assemblies.

10. The hydrophone assembly of claim 9 , wherein each of the non-acoustic sensor assemblies includes one or more non-acoustic sensors.

11. The hydrophone assembly of claim 4 , wherein the ring assemblies are triplet ring assemblies, each comprising three acoustic sensors.

12. The hydrophone assembly of claim 4 , wherein the ring assemblies are coupled together by a cable.

13. 13. The hydrophone assembly of claim 12, wherein the cable is at least 10 feet long and the ring assemblies are separated by at least 10 feet when deployed.

14. The hydrophone assembly of claim 4 , further comprising a canister in which the array pack resides prior to deployment and partially during deployment.

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