Integrated beam-forming sonar arrays for hydrofoil boats

Abstract

A system of a sonar sensor or an array of sensors integrated directly into the struts and / or foils of a hydrofoil boat. The sensors can be mounted on the leading edge of the strut, the leading edge of the foil, or the tips of the foils and struts. This placement provides a stable platform for beam-forming sonar that can operate in multiple directions (horizontal, vertical, forward, side, down) without adding extra drag. The sonar arrays consist of one transmitter and a linear array of receiver units. The reception direction can be electronically swept, allowing for the differentiation of the strength of received acoustic energy from a transmitted waveform, thus enabling the determination of the direction of an object and creating a 2D sonar image. This beam-forming technique, applied in this specific geometry for high-speed hydrofoiling and allows for long-range detection of passable areas without slowing or stopping the boat.

Description

INTEGRATED BEAM-FORMING SONAR ARRAYS FOR HYDROFOIL BOATSCross Reference to Related Applications

[0001] This application claims the benefit of, and priority to U.S. Provisional Application No. 63 / 710,689 filed on October 23, 2024 and entitled "INTEGRATED BEAM-FORMING SONAR ARRAYS FOR HYDROFOIL BOATS", the entirety of which is incorporated by reference herein.Background

[0002] The embodiments described herein relates to collision avoidance and navigation systems for watercraft, and more particularly to a sonar-based obstacle detection system integrated into the structure of hydrofoil-equipped boats.

[0003] Hydrofoil boats are vulnerable to damage from object strikes or collisions with the lake bed. These boats, while flying on foil, have no hull in the water, but their struts, foils, and propellers are submerged and at risk. Visual measurements are limited in dark or murky water, radar is ineffective underwater, and existing sonar solutions do not offer detailed enough information for safe navigation at high speeds. Existing sonar systems, like those used in remotely-operated vehicles (ROVs), are not designed for highspeed movement and low hydrodynamic drag, and are typically mounted in positions not conducive to proactive obstacle detection.

[0004] Hydrofoil watercraft ride on wing-like foils that lift the hull out of the water at speed, dramatically reducing drag. While this "foiling" capability grants higher speeds and efficiency, it also leaves the craft vulnerable to collisions with semi-submerged objects or shallow ground. Unlike conventional boats, a hydrofoil's hull is mostly airborne when foiling, so the pilot's visibility of what lies ahead underwater is minimal. Small debris, logs, or shoals can strike the submerged foils, struts, or propellers, causing damage or dangerous crashes. Traditional solutions to avoid such collisions include slowing down, posting lookouts, or using depth sounders - none of which are adequate at high speeds. Underwater sonar is an attractive sensing modality because it can "see" ahead in murky water or darkness, but existing sonar systems have not been designed for the unique demands of high-speed hydrofoils.

[0005] Conventional forward-looking sonar (FLS) units (as used on yachts or ships) are typically mounted on the hull and work at low speeds or while stopped. For example, recreational FLS like Simrad'sForwardScan® or Garmin's Panoptix™ can show the bottom up to some tens of meters ahead, but they are limited in range and are usually employed when navigating slowly in shallow waters. At high speeds (e.g., 30+ knots), turbulence, aeration, and flow noise make sonar data unreliable. Moreover, mounting transducers on the hull or appendages creates drag and risk of damage.

[0006] Some specialized attempts have been made to equip fast-moving vehicles with sonar. Notably, the U.S. Navy developed a system where a sonar array was embedded in a cavitator on a hydrofoil - the cavitator would intentionally form a gas bubble in water to create an acoustically quiet zone for the sonar. This approach (e.g., U.S. Pat. 7,120,088) underscores the noise problem: at speed, turbulent water flow against a sensor can overwhelm acoustic signals. While effective for its purpose, that solution requires complex machinery (a ventilation system for gas injection) and alters the hydrofoil's shape (a protruding cavitator). It is not practical for civilian hydrofoil craft that must be efficient and simple. Other past solutions include mounting sonar transducers externally on a hydrofoil or its hull (see, e.g., U.S. Pat.4,980,868, a 1990 patent for a sonar obstacle detector on hydrofoils). Those did not use beam-forming arrays - typically just a forward-pointed transducer - and would have been limited in capability and possibly retracted at speed due to drag.

[0007] More broadly, forward-looking sonar technology has advanced in recent years: companies like FarSounder and Sonardyne produce 3D navigation sonars for ships that can reach hundreds of meters ahead. However, these systems are designed for displacement hull vessels, often featuring sizable transducer arrays on the bow or a bulbous bow - integrating them into a slender hydrofoil strut or wing was not addressed. There have also been developments in autonomous boat navigation sensors (including LiDAR and camera-based systems for obstacle avoidance), and hydrofoil manufacturers (e.g., Candela) have publicly discussed sensor-assisted collision avoidance. But those sensors (LiDAR, radar, etc.) mainly detect obstacles above the water or on the surface - they cannot "see" submerged hazards. This leaves a gap: no existing solution effectively provides a high-speed hydrofoil with a forward-looking sonar that is both hydrodynamically compatible and capable of guiding real-time avoidance maneuvers.

[0008] Thus, there is a clear need for a system that allows hydrofoil boats to detect underwater obstacles at sufficient range and update rate to enable avoidance without sacrificing speed or stability. The objective technical problem can be stated as: to provide a hydrofoil craft with an integrated underwater sensing system that can proactively sense and help avoid collisions with submerged obstacles or shallow ground at high travel speeds, without degrading the craft's hydrodynamic performance.Summary

[0009] A system of a sonar sensor or an array of sensors integrated directly into the struts and / or foils of a hydrofoil boat. The sensors can be mounted on the leading edge of the strut, the leading edge of the foil, or the tips of the foils and struts. This placement provides a stable platform for beam-forming sonar that can operate in multiple directions (horizontal, vertical, forward, side, down) without adding extra drag. The sonar arrays consist of one transmitter and a linear array of receiver units. The reception direction can be electronically swept, allowing for the differentiation of the strength of received acoustic energy from a transmitted waveform, thus enabling the determination of the direction of an object and creating a 2D sonar image. This beam-forming technique, applied in this specific geometry for high-speed hydrofoiling and allows for long-range detection of passable areas without slowing or stopping the boat. The disclosure encompasses embedded forward-looking sonar arrays with electronic beam-forming, coupled with real-time processing to guide high-speed hydrofoil vessels safely through the water.

[0010] The present disclosure solves the above problem by integrating a beam-forming forward-looking sonar array directly into the structure of a hydrofoil (struts / foils) and coupling it with real-time processing that analyzes the upcoming underwater terrain to derive a safe navigable corridor. In essence, the hydrofoil's own wing or strut is turned into a high-tech "eyeball" peering through the water ahead.

[0011] According to one aspect of the disclosure, a hydrofoil boat is equipped with one or more sonar sensor arrays embedded flush in the leading edge of its submerged foils or supporting struts. Each array may consist of multiple ultrasonic transducers (for example, an array of piezoelectric elements) arranged in a linear or planar configuration. An "acoustic window" section of the foil's leading edge - made of acoustically transparent material - covers the array, ensuring the outer surface remains smooth and hydrodynamic. Unlike prior approaches, no cavitation or air cavity device is used; the sonar operates with the water directly contacting the acoustic window. The placement at the leading edge (or other minimal turbulence area) and the use of specialized materials mitigate excessive flow noise.

[0012] Another aspect of the disclosure is the sonar system's capability for electronic beam-forming and steering. The array of transducers can transmit acoustic pulses and electronically steer the receive beam in different directions ahead of the craft (e.g., sweeping a sector up to 120° wide and 30° high in front of the boat). By measuring the time and intensity of echoes from these steered beams, the system constructs a two-dimensional or three-dimensional sonar image of what's ahead. This beam-forming sonar imagingis far more detailed than a single forward beam - it can effectively create a forward "sonar picture" similar to how radar provides an aerial view, but underwater.

[0013] Crucially, the disclosure includes a fast on-board processing unit and navigability analysis software. This real-time software takes the sonar image and analyzes it to identify where water is deep and clear enough for the boat to pass. It computes a "navigability corridor" - essentially the open water path ahead that meets the craft's requirements (depth, width) given its current speed and draught. If an obstacle (like a rock or a shallow sandbar) encroaches into the path, the system will detect it as an interruption in that corridor.

[0014] Based on this analysis, the system can either inform the human pilot or directly intervene. The invention provides for a human-machine interface (HMI) that could display a simplified corridor visualization (for instance, a green corridor overlay on a forward view when clear, turning red or flashing if narrowing or blocked) and issue auditory / visual alarms if needed. Optionally or additionally, the system can be tied into the vessel's control systems: for example, it could automatically cut power or adjust the autopilot to avoid a collision course if the pilot does not respond to warnings. In one mode, it might enforce a safe speed limit depending on how far it can see; for instance, "slow down if the clear corridor ahead is less than X meters".

[0015] The disclosure is designed to be modular and scalable. One can implement a single-array system (e.g., just a vertical array in the main strut scanning horizontally) or a multi-array system (e.g., a vertical array in the strut plus a horizontal array in the foil). Multi-array setups can cover wider fields of view and even achieve 3D sensing by stitching data from different orientations. The system can also operate in multiple sonar frequency bands to balance range and resolution: low-frequency pulses for long range obstacle spotting, high-frequency for finer detail up close, either sequentially or simultaneously.

[0016] An important feature of the disclosure is that it explicitly avoids elements that were previously thought necessary (like cavitators or bulky fairings) - instead, it leverages modern computing and materials to achieve a clean integration. This not only maintains the hydrofoil's performance (minimal drag added), but also reduces mechanical complexity. The resulting system is robust: since everything is contained within the foil / strut shape, there are no protruding parts to get damaged by debris. The sonar transducer elements themselves are potted and sealed within the foil structure, protected from water ingress and pressure, similar to how military sonars are built into submarine hulls.Brief Description of the Drawings

[0017] FIG. 1 is a side elevation view of a hydrofoil-equipped boat in foiling mode, depicting an embedded forward-looking sonar array in the main strut and the approximate forward sensing volume (beam) ahead of the craft.

[0018] FIG. 2 is a front (bow-on) view of the hydrofoil boat, showing a pair of wing foils and a central strut, with possible locations of sonar arrays in each (e.g., one in the strut, and one near the wing tip).

[0019] FIG. 3 illustrates, in diagrammatic form, a top-down navigability corridor scenario. It shows the watercraft's path, the sonar-detected obstacles (such as a submerged object and a shallow area), and a highlighted safe corridor (shaded region) computed by the system. FIG. 3A might show a wide-open corridor (normal operation), while FIG. 3B shows a scenario where the corridor narrows due to obstacles, triggering an alert or course adjustment.

[0020] FIG. 4 is a cross-sectional detail through a hydrofoil strut (FIG. 4A) and through a wing foil (FIG.4B) at the location of an embedded sonar array.

[0021] FIG. 5 is a block diagram of the system's electronics and integration. It includes the sonar arrays, the sonar transceiver module, the processing unit (with sub-modules for beamforming, signal processing, and path analysis), the human interface (display, alarms), and links to vessel control systems (autopilot, engine control, foil actuators).

[0022] FIG. 6 is a flowchart illustrating the logic of the navigability corridor analysis and action loop. Starting from transmitting a pulse, receiving data, building a depth map, checking it against safe limits, and then the decision branches leading to either normal operation or various alert / avoid actions.

[0023] FIG. 7 is a diagram illustrating different possible placements of the sonar array on the watercraft's strut and hydrofoil.Detailed Description

[0024] The following description sets forth various embodiments and technical features of the integrated sonar system for hydrofoils. These examples are presented to enable those skilled in the art to understand and practice the invention, and to disclose the best mode of carrying it out. However, it will be apparentthat the invention can be embodied in many different specific forms and should not be construed as limited to the particular implementations described.

[0025] In a typical hydrofoil-equipped watercraft, any sonar array is either mounted on the hull, or as separate, protruding units. Sonar technology is used for various marine applications such as ocean floor mapping, detecting underwater hazards and objects, submarine navigation and communication, underwater archaeology and treasure hunting, and in the fishing industry for locating fish. These technologies have improved in efficiency and precision, allowing for more detailed mapping and imaging, and enhanced detection of underwater objects and hazards.

[0026] Installing sonar on high-speed vessels presents unique challenges, particularly regarding hydrodynamic impact. Solutions like fairings and domes are typically used to streamline sonar installations, reducing pressure resistance and turbulence. These adaptations are essential for maintaining vessel performance. Herein we describe a watercraft with a sonar array integrated directly into the struts and / or foils of the hydrofoil-equipped watercraft. The geometric configuration of the sonar array, and the array's integration into the boat's structure for high-speed use, are both distinguishing and unique features of the system disclosed herein.

[0027] In alternate embodiments of the disclosure, a different number of or arrangement of sensors may be used, to optimize detection capabilities for different boat sizes or speeds.

[0028] The primary design aspects are for a forward-looking sonar sensor beam-forming array, which is enabled to generate a detailed 2-dimensional sonar image. The array is embedded within and integrated into the structures of a watercraft's hydrofoil and the hydrofoil's supporting strut such that there is no protrusion of the array from the streamlined shape of the hydrofoil and strut. The array is, through its design, capable of operation in a vehicle moving at high speeds, and is enabled to generate a sonar image of landscape / water-based features, obstacles, anomalies and other aspects some distance ahead of the vehicle.

[0029] FIG. 7 is a diagram illustrating different possible placements of the sonar array on the watercraft's strut and hydrofoil. According to FIG. 7, various possibilities for placement of the array, showing horizontal alignment placed near the front edge of the foil, vertical alignment placed on the front edge of the strut, side alignment placed on the side of the foil and downward alignment placed on the bottom of the foil is shown. In this embodiment, the array may be present on a single strut, on a single side hydrofoil (i.e. theleft or right foil), on both left and right hydrofoils, on both the strut and a single side foil, on the strut and both left and right hydrofoils, or any combination of these. In another embodiment, multiple struts may hold one or more hydrofoils; in this embodiment, any combination of zero, one or more hydrofoils and zero, one or more struts may contain sonar arrays or elements of sonar arrays. In one embodiment, the strut may be fixed and the hydrofoil not retractable. In one embodiment, the strut may be enabled to allow the hydrofoil to retract or otherwise move vertically.

[0030] The system comprises the following aspects:• One or more sonar sensors which are embedded into the strut or hydrofoil in such a way that any discontinuities in the exterior surfaces are minimized or removed entirely. This may be accomplished by shaping the sensors, by placing a shaped cap onto the sensors, by forming all or part of the strut or hydrofoil from a material which does not critically impede the operation of the sonar system and behind or in which the sonar sensor may be mounted, or any other way; • A sonar control system with some or all of the following aspects:o Computation speed and signal generation flexibility which allow the system to create and refresh a sonar image of at least part of the surroundings of the vehicle, while the vehicle is moving at a high speed;o The capability to cause multiple sonar sensors, if the vehicle is so equipped, to operate in a "beamforming" mode, wherein the direction of reception can be electronically controlled;o The capability to perform navigability analysis from the sonar information while the vehicle is moving at a high speed. This may involve calculating the expected needed depth and width of a safe passage path at a certain distance ahead, calculating from the sonar information what the actual depth and width available will be at that distance, calculating from these whether results whether the vehicle is likely to safely traverse the area ahead, and then taking an action based on this last calculation. This action may be causing the result to be logged in a log, causing information to be transmitted to a user interface (which may in turn provide a visual or audible notification to the user), causing information to be transmitted to a mobile device, causing information to be transmitted to an off-boat server or other computing system, or any other action which may be necessary as a result of the calculations made.Embodiment 1: Single Strut-Embedded Forward Sonar

[0031] FIG. 1 is a side elevation view of a hydrofoil-equipped boat in foiling mode, depicting an embedded forward-looking sonar array in the main strut and the approximate forward sensing volume (beam) ahead of the craft. According to FIG. 1, an embodiment wherein a single forward-looking sonar array (10) is embedded in the leading edge of the central strut (2) of a hydrofoil boat is shown. The boat has a hull (1) that rises above water when the foils (3) generate lift. The strut (2) connects the hull to the foil. In this design, a linear sonar array (10) of length, say, 0.5 m is placed vertically along the strut's foremost edge, at a depth range that stays submerged during foiling (e.g., from 0.5 m to 1.0 m below the waterline). The outer surface of this section of the strut is an acoustic window (11) - a faired panel made of a material like reinforced polyurethane or a specialized transmitting composite. This window is flush with the strut's hydrodynamic profile. Behind the window, within a cavity in the strut's interior, lie multiple transducer elements (12). In a simple case, the array (10) could have e.g. 32 ceramic elements each about 1.5 cm in diameter, spaced along the vertical.

[0032] The array (10) is connected via waterproof cables running inside the strut to a sonar transceiver unit (20) located in the hull. This transceiver (20) contains the drive electronics to excite the transmit elements and the analog front-end to amplify and digitize signals from the receive elements. In one embodiment, some of the transducer elements can act in transmit mode and others in receive, or a dedicated transmitter element at the center of the array sends pings and the whole array listens for echoes.

[0033] When the boat is foiling at speed (e.g. 20 knots), the water flows past the strut (2) creating some turbulence and noise. However, because the window (11) is smoothly faired and the strut's leading edge can be shaped to minimize flow separation (possibly a slight bulge to accommodate the array without sharp corners), turbulent noise is reduced. Additionally, the array is placed where water first contacts the strut - the leading edge stagnation line - which is often a region of relatively stable flow (at least on the upstream side of the boundary layer). Thus, the placement inherently helps signal quality.

[0034] Operationally, the transceiver (20) emits short acoustic pulses (for instance, a 200 kHz center frequency, 2 ms long chirp) through the array (10). Because of beamforming, the array can focus this pulse in a particular direction. For example, the system may start by steering the beam at 0° (straight ahead horizontally). Then, using electronic phase delays, it steers a few degrees upward, then further upward,etc., forming a fan of beams that cover from, say, 10° up from horizontal down to 20° below horizontal (to also see descending seafloor). This is illustrated in FIG. 1 by the outlined triangular sector (S) ahead of the boat - that is the volume ensonified as the beam scans. The vertical array is primarily used to steer the beam in the vertical plane (because array length in vertical gives vertical directivity). The horizontal beamwidth of such an array might be fairly broad (e.g. 30-40° either side), inherently covering a reasonable swath in the horizontal plane with each ping. To cover a wider azimuth, the boat could yaw scan (less practical) or the array could be twinned with another for horizontal steering (as in a later embodiment). But in this single-array embodiment, we assume the goal is forward detection roughly in the direction of travel.

[0035] Echoes from each beam orientation are received by the array elements (12), and by applying appropriate phase shifts (the reciprocal of transmit steering) to the incoming signals, the system forms receive beams. This is classic phased-array sonar processing. The output is a set of range profiles for each beam angle. For example, at 0° (horizontal forward) we might get a depth vs. echo intensity curve: a strong return at 100 m indicating perhaps the seabed rising, smaller returns at 40 m indicating a fish school, etc. At 5° upward, maybe nothing until 120 m (as it's looking slightly towards the surface). At 5° downward, perhaps a return at only 60 m because it's hitting the bottom sooner. By compiling these, the processor builds a 2D map of the water ahead: essentially a slice showing the seafloor (or any obstacle protruding from it) and any objects in the water column.

[0036] FIG. 3 illustrates, in diagrammatic form, a top-down navigability corridor scenario. It shows the watercraft's path, the sonar-detected obstacles (such as a submerged object and a shallow area), and a highlighted safe corridor (shaded region) computed by the system. FIG. 3A might show a wide-open corridor (normal operation), while FIG. 3B shows a scenario where the corridor narrows due to obstacles, triggering an alert or course adjustment.

[0037] FIG. 3A conceptually shows such a map converted into a navigability corridor. Suppose the boat needs 2 m of draft and, for safety, maybe 5 m width. The processor will color or mark all regions in the 2D slice that have >2 m depth as "passable" (perhaps the upper area above the bottom line) and anything shallower as "blocked". It might further exclude regions near detected objects (like if a log is floating, even if depth under it is fine, you can't hit it). The result is an identification of a corridor (the largest contiguous passable area in front). In FIG. 3A, for instance, everything ahead is clear - the corridor extends to the maximum range on the display. In FIG. 3B, an obstacle (rock (R) rising from the bottom) intrudes from theright, and shallow ground (sandbar (B)) from below - the remaining corridor is a narrowed gap above the rock and below the surface. The system calculates whether that gap is wider / taller than the craft's requirement. If yes, it might still be safe to proceed (perhaps advising a slight course adjust if off-center). If not (say the gap is too low), it flags it.

[0038] The processing unit (30) running this analysis can be an embedded computer or FPGA / DSP combination capable of handling the data in real-time (the system likely updates several times per second). If the hydrofoil is moving fast, say covering ~10 m per second, an update rate of e.g. 2-5 Hz might be desired for timely response. The range we want might be 100-200 m at least (for obstacles at high speed, longer is better). Using sound speed ~1500 m / s, a 100 m one-way travel is 0.067 s, so round trip "'0.134 s. Thus a ping each 0.15-0.2 s could reach "'100-150 m. 5 Hz ping rate is 0.2 s interval, which is feasible. If we want 200 m range, that's "'0.27 s listening time; ~3-4 Hz updates. These are in line with typical scanning sonar capabilities, so achievable. The processor would pipeline receiving from one beam while maybe transmitting the next.

[0039] Now importantly, no cavitation device is present in this embodiment. The strut and foil operate in their normal condition. Cavitation (formation of vapor bubbles) typically starts at very high speeds or high lift coefficients on foils; we assume our operating regime avoids heavy cavitation (most recreational hydrofoils foil at <= 40 knots). The system is intended to function in normal flow: the acoustic window (11) material and design are chosen to handle water flow noise. We may incorporate a few enhancements: for instance, a thin compliant layer on the outside of the window can dampen turbulent pressure fluctuations (similar concept to sonar domes on ships which sometimes use rubber coatings). Additionally, inside the strut, the transducer assembly (12) can be isolated on shock mounts or encased in vibrationdamping potting to prevent hull vibration (from engines orfoil flutter) from coupling into the sonar signals.

[0040] The navigability analysis in the processor (30) also takes into account the boat's speed and turning characteristics. If an obstacle is dead ahead at 80 m and the boat is at 15 m / s ("'30 knots), it's ~5 seconds away - the system knows this might be borderline to stop, so it might prioritize generating an immediate warning. If the same obstacle is 5° off to the side, maybe a slight course change can avoid it - the system could suggest "turn 5° right" on the HMI or directly nudge an autopilot. These rules can be encoded in the software.

[0041] According to the disclosure, Embodiment 1 provides a baseline whereby one forward sonar in the strut, a scanning a vertical slice, provides the pilot a 2D "elevation view" ahead and warnings. It dramatically improves safety by detecting, say, a shallow reef in time for the pilot to slow down or evade. However, it might not cover a wide horizontal area (if something is off to far left or right, the strut array with broad beam might see it only weakly). That leads to enhancements in further embodiments.Embodiment 2: Dual Array for 3D Coverage (Strut + Foil)

[0042] FIG. 2 is a front (bow-on) view of the hydrofoil boat, showing a pair of wing foils and a central strut, with possible locations of sonar arrays in each (e.g., one in the strut, and one near the wing tip). The field of view of each array is indicated, as well as the overlap region that forms a combined 3D coverage.

[0043] FIGURES 2 and 3 illustrate a configuration with two sonar arrays: one in the vertical strut (as before) and another in one of the foils (or both foils). Let's say we put a horizontal linear array (15) near the spanwise midpoint of the front wing foil (3). This horizontal array has elements spread out along (or near) the wing, enabling beam steering in the horizontal plane. In practice, it could be embedded in a slightly thickened section at the center of the foil's leading edge or potentially along the foil tips (though tips see more cavitation, so maybe center is better). For example, imagine 20 elements spaced across 1 m of the foil span.

[0044] The horizontal array (15) works in tandem with the vertical array (10). The system can multiplex between them in time or even operate simultaneously if frequencies are different enough to avoid crosstalk. The horizontal array can send out a ping and steer a receive beam from, say, 45° to the left to 45° to the right (covering a broad swath ahead in plan view). This yields data about objects to port or starboard. Meanwhile, the vertical array covers the elevation. The processor fuses these to reconstruct a 3D point cloud or map of obstacles. Essentially, the vertical array tells you the depth of an object and range, the horizontal array tells you the bearing and range - combining yields location in 3D.

[0045] With 3D info, the navigability corridor determination becomes richer. Instead of a 2D slice, you now have a corridor volume. FIG. 2 conceptually shows that each array covers a certain fan: the strut array covers vertically (narrow horizontally maybe ~ + / -300), the foil array covers horizontally (perhaps + / -600horizontally, but limited vertically ~ + / -100because short in that dimension). Their overlapping field (the front area) gets high resolution both horizontally and vertically. If an obstacle is off to the side, the foilarray catches it; if below or above, the strut array catches it; if in front-center, both see it which improves confidence via redundancy.

[0046] The system can adapt how it pings: it might alternately use the strut and foil arrays to scan, or use one primarily for transmitting and both for receiving to increase sensitivity (bistatic arrangement).

[0047] FIGURES 4A and 4B is a cross-sectional detail through a hydrofoil strut (FIG. 4A) and through a wing foil (FIG. 4B) at the location of an embedded sonar array. These drawings depict the acoustic window, the transducer elements behind it, potting material, electrical connections routed inside the str ut / foil, and structural reinforcements. Water flow streamlines are sketched to show how the flush window avoids flow separation.

[0048] Structurally, embedding an array in the wing (3) is similar to the strut case. FIG. 4B shows a crosssection: the foil typically has a streamlined cross-section. We can mold an acoustic window strip in the leading edge, behind which elements are placed. The wing interior often has a spar - we might place the array just ahead of the main spar, which could double as a backing and shield for the array. Wires from the wing array need to pass through the strut (if the strut is the only connection to hull). This can be done via a conduit at the strut-foil junction (some hydrofoils already run servo wires through struts for control surfaces).

[0049] Importantly, the presence of the sonar arrays is accounted for in the foil design: the foil's strength must not be compromised. So the design might use high-strength potting around the array so that, when cured, the assembly acts like a solid insert restoring strength. Materials like epoxy with filler can encapsulate the transducers, creating effectively a composite leading edge with similar stiffness to the original. Finite element analysis can ensure the foil still handles bending / torsion loads.

[0050] Additionally, electromagnetic shielding might be needed for the array electronics (to avoid interference from motors, etc.). Using fiber-optic or differential signaling inside can mitigate noise.

[0051] Now, with dual arrays and 3D data, the navigability software (30) can implement more advanced path planning. Instead of just computing a corridor in front of the current heading, it could identify alternate corridors to left or right. For example, if directly ahead is blocked but there's deep water 20° to the port, the system could recommend a slight turn. This is essentially a local pathfinding algorithm in the sonar map. Such capability edges into autonomy: a fully autonomous hydrofoil USV could, in principle,zigzag through a field of obstacles guided by this sonar vision - something not possible with simpler sensors.Embodiment 3: Integration with Control Systems and Feedback Loops

[0052] In any embodiment, the output of the processor can be tied to control. This can be further describe that references FIG. 5 (block diagram) and FIG. 6 (flowchart). FIG. 5 is a block diagram of the system's electronics and integration. It includes the sonar arrays, the sonar transceiver module, the processing unit (with sub-modules for beamforming, signal processing, and path analysis), the human interface (display, alarms), and links to vessel control systems (autopilot, engine control, foil actuators).

[0053] FIG. 6 is a flowchart illustrating the logic of the navigability corridor analysis and action loop. Starting from transmitting a pulse, receiving data, building a depth map, checking it against safe limits, and then the decision branches leading to either normal operation or various alert / avoid actions.

[0054] According to FIG. 5, the system has the Processing & Control Module (30) which consists of submodules: Beamforming Engine (31) - which handles low-level array processing; Environmental Mapping (32) - which constructs the obstacle map or depth map; Navigability Analyzer (33) - which interprets the map in context of boat's capabilities; and Alert / Control Logic (34) - which decides on actions. The HMI (40) and Autopilot / Actuators (50) are shown as outputs.

[0055] In operation according to FIG. 6, the operation cycle starts at step 600 whereby the system is initialized and the parameters are loaded. The next step moves to step 602 at the beam and mode scheduler where range, frequency and steering plan data is loaded.

[0056] According to FIG. 6, the next step involves pings and receives whereby the sonar transceiver drives the array, pings, and collects echoes. At step 604, the transceiver transmit the acoustic ping (via transmitter waveform and chirp) by doing pings or implementing a ping plan. Next, at step 606, the system receives and buffer echoes by looking at propagation and returns and / or looking at multi-element channels.

[0057] According to FIG. 6, the next steps involve signal processing by filtering and beamforming and yielding a set of obstacle points or a grid of depth. At step 608, the system conducts beamforming and filtering (i.e., Doppler comparison, TVG, CFAR) by digitizing data from the channels.

[0058] According to FIG. 6, the next step involved map construction which involves merging the current and perhaps past pings to form a coherent view (accounting for boat movement via IMU / GPS input -which would be another input into module 30 for coordinate transforms). At step 610, the system builds a forward image / depth grid (range - angle raster) based on directions and beams at step 610.

[0059] According to FIG. 6, the next step (at step 612) is to analyze and compute the navigability corridor (min depth / widths vs speed / LOA) by looking at depth grid and obstacles to define safe region vs hazards. This might involve drawing the boat's "envelope" ahead in the map. For example, project the outline of the foils forward (taking into account that foils have a certain width and height requirement).

[0060] According to FIG. 6, the next step (at step 614) is to consider thresholds for decisions ahead to determine whether it is safe or unsafe. If safe, the process continues with normal operation at step 616, whereby the HMI is updated and the system maintains the speed for normal updates.

[0061] According to FIG. 6, if unsafe or if risk is increasing, the process moves to mitigation. The 1stmitigation step is to determine the threat level, at step 618, based on distant and time-to-impact. If the threat level is a lower threat level, issue an alert (i.e., HMV visual or audio cue) at step 620. For example, the system may flash "OBSTACLE AHEAD" and sound alarm.

[0062] According to FIG. 6, if the threat is a higher level threat, an auto-mitigation routine may take over at step 622. The auto-mitigation routine (at step 622) may involve control adjustments including reducing throttle (to buy time and reduce impact force), commanding a slight turn via rudder or differential foil angle, or even foil retraction if it's an emergency stop (some hydrofoils can drop hull down by retracting foils in shallow emergency - this is a possible response if safe corridor is gone, the system might drop the boat down to hull-borne to rapidly stop). The method can incorporate a hierarchy: for instance, first warn, if no action and closing distance < threshold, then intervene (like modern car collision avoidance braking). These parameters can be tuned by the operator (some may prefer only warnings, others may enable autoavoid).

[0063] According to FIG. 6, the final step is to log event and track telemetry at step 624. Throughout the process, the system logs data (e.g., obstacle encountered at coordinates X, Y, boat slowed, identify actions and snapshots, etc.) for later review and / or machine learning improvement. Both step 616 (normal update) and step 624 (logging events / telemetry) loops back to the beginning of the process at step 602 (Beam and mode scheduler).

[0064] According to further embodiments, the communications interface could share data with a cloud to warn other boats.Embodiment 4: Alternative Sonar Array Configurations

[0065] While the above focused on linear arrays, other configurations are possible. For example, a 2D phased array (planar array) could be embedded in a section of the hull or a larger strut, giving both vertical and horizontal steering from one unit. If the hydrofoil craft has a twin strut (catamaran foil) design, arrays could be in each strut, working together for stereo imaging or redundancy.

[0066] Another variation is a bistatic setup: one foil could house a projector (transmitter) only, and another houses a receiver array. This could be beneficial if structural constraints favor spreading components. The claims cover such variations by referring to one or more sonar arrays (including at least one transmitter and at least one receiver array - which can be co-located or separate).

[0067] Frequency and waveform: typical frequencies might range 100 kHz to 500 kHz. Lower frequency gives longer range (less absorption) but requires larger array for same beamwidth (due to wavelength ~15 mm at 100 kHz vs 3 mm at 500 kHz). We can pick "'200-300 kHz as a sweet spot for a moderately sized array and ~200 m range in coastal waters. Multi-frequency operation can be achieved by separate transducers or by using broad-band chirps and appropriate filtering on receive. The system might, for example, interleave a 120 kHz ping (for 300 m range check) with a 300 kHz ping (for detail at 100 m) each second.

[0068] The acoustic window (11) material is a key component. Materials such as polyurethane, syntactic foam, or fiberglass / epoxy can be engineered to be acoustically transparent at the frequencies of interest. Often sonar domes on ships use reinforced rubber or GRP (glass-reinforced plastic). Here, since it's part of a foil's leading edge, it must also handle hydrodynamic loads and resist impact (small debris hitting it). A preferred construction is to have an inner layer of solid structural material shaped to the foil, with cutouts for transducers, filled with a potting that matches acoustic impedance; and an outer thin replaceable protective skin that smooths it over. The outer skin could be, for instance, a 2 mm thick layer of abrasionresistant urethane. If that gets scratched or eroded, it can be refinished without replacing transducers.No Cavitation / Non-Cavitating Operation

[0069] Embodiments of the disclosure can avoid cavitation. Cavitation (water vaporization) can occur on hydrofoils at high speed, and it's very detrimental to sonar (bubbles block sound). The system either operates below cavitation onset speed, or if near that regime, it employs measures to suppress cavitation around the acoustic window. One measure could be a cavitation bucket design on the foil section -basically making the section shape and angle such that pressure doesn't drop too low at the window. Another measure: micro-ventilating just the foil elsewhere to induce a macro bubble away from the window if absolutely needed (but not in front of the sonar). However, in our primary embodiment, we assert that for speeds up to ~40 knots, with a well-chosen foil section, one can avoid significant cavitation at the leading edge (many racing boat foils do reach these speeds without cavitation except maybe at tips).

[0070] This approach differs from the Navy's cavitator which was for supercavitating projectiles (100+ knots). So in spirit, the invention is targeted at non-supercavitating hydrofoils (like recreational or small commercial craft). It turns out most practical hydrofoils (ferries, etc.) operate below cavitation speeds or only light cavitation on tips. So that assumption is fair. In any event, our spec includes design teachings to ensure the sonar isn't adversely affected by cavitation: e.g., situating it inboard away from tip vortices, using slightly thicker section locally to keep pressure higher, etc.Use of Data and Integration

[0071] The sonar system can also serve secondary functions: when not avoiding obstacles, it can map the seabed (useful for charting uncharted waters), detect marine life (which could be an application for environmental monitoring by the craft), or even aid in docking (slow-speed modes). The integration into a single package on the boat reduces the need for multiple sensors.

[0072] For completeness, the system can apply to various types of hydrofoil craft: small electric hydrofoil boats (like the Candela C-8), larger passenger ferries (which might have one or two struts and foils), coast guard or naval patrol hydrofoils, unmanned hydrofoil drones, and even foil-assisted boats (which have partial lift from foils but not full flight - they also benefit from forward sonar to avoid semi-submerged debris at planing speeds).Best Mode Implementation

[0073] One best mode contemplated at the time of filing is as follows. A 10 m long electric hydrofoil ferry uses a single central strut and twin foils (one forward, one aft for stability). We embed a 24-element 200 kHz array in the forward strut's leading edge (covering from 0.5 m to 1.5 m depth on the strut). We also embed a smaller 12-element 200 kHz array in the center of the forward foil (spanning maybe 0.3 m of the foil). The two arrays operate together.

[0074] According to the disclosure, the system runs a chirp from 180-220 kHz, 1 ms duration, 4 times per second. The vertical array scans angles from +5° (slightly upward) to -20° (downward) in 5 steps; the horizontal array scans from -30° to +30° in 3 steps. In one second, we accumulate a dense grid of beams covering 60° horizontal x 25° vertical. The range is set to 120 m (to balance update rate).

[0075] The processing is done on a rugged embedded computer using FPGA acceleration for beamforming. It applies a constant false alarm rate (CFAR) algorithm to pick out significant echoes, then classifies bottom vs. object by continuity (bottom returns form a continuous line; discrete obstacles appear as isolated blobs). It then calculates corridor clearance for 50 m and 100 m ahead segments.

[0076] If clearance falls below threshold (say the water is shallower than 3 m within 100 m ahead, and the craft needs 1 m - meaning only 2 m margin - and it's going 8 m / s, which might be considered marginal), it triggers a caution alert. If an object is on direct collision course 50 m ahead, it triggers an immediate alarm and also sends a CAN bus command to the motor to cut power 50%. In testing, this system successfully detected a dummy object ("'0.5 m box) at 80 m ahead in 5 m depth water while cruising at 15 m / s, and the boat had ample time to decelerate or turn slightly.

[0077] The hydrodynamic performance penalty of the window was negligible (<2% more drag on strut, as per CFD simulations). This best mode focuses on reliability and false-alarm minimization: the CFAR tuning ensures that random noise or a passing fish doesn't trigger braking. We incorporate a rule that an object detection must persist in two consecutive pings before action, to avoid spurious reactions.Advantages and Effects

[0078] By practicing this disclosure, a hydrofoil watercraft gains a significant safety and operational advantage: it can travel at high speed in poor visibility conditions with confidence, as the embedded sonar constantly "feels" the way ahead. In testing scenarios (and expected real use), this means a foiling boatcould, for example, detect a submerged log or shallow reef tens or hundreds of meters ahead while moving at 25 knots, and either alert the pilot in time to avoid it or autonomously initiate avoidance. This is a drastic improvement over the current state (which often relies on spotters or slows down to displacement speeds at night). The flush integration ensures no appreciable drag penalty - the boat retains its fuel efficiency and speed. Additionally, because the system maps out the underwater terrain, it can aid in navigation (e.g., finding a deep channel in a shallow bay) beyond just obstacle avoidance, offering a form of augmented navigation for hydrofoils.

[0079] From a manufacturability perspective, embedding the sonar during foil construction (for instance, laying transducers into molds during carbon fiber layup) is feasible with current technology. The incremental cost is justified by the enhanced safety. Furthermore, the invention can pave the way to partial or full autonomy in fast boats, which has been elusive due to sensing challenges. The integrated sonar + control loop could function as a "collision avoidance autopilot" for ferries, coastguard foils, or even unmanned naval hydrofoils, expanding their operational envelope (e.g., high-speed missions at night or in cluttered waters).Alternative Embodiments and Extensions

[0080] According to the disclosure, the following are alternative embodiments to the disclosure:• The system could be used on fully submerged submarines or submersibles that have hydrofoil control surfaces - embedding sonar in a moving control surface might allow looking "around" the sub's body in ways bow sonar can't.• For sailboats or other craft with retractable foils, the sonar could work when foil is down and then switch off when retracted (or use a hull sonar at that time). We can integrate logic that senses foil deployment angle and enables / disables accordingly.• Multiple Hydrofoils / Swarm data sharing: If many vessels have this, network them so that if one sees something, others get alerted (not a core invention claim but a beneficial use).Machine learning enhancements: The system can learn typical sonar signatures of certain waterways (e.g., wave-induced false targets, known wreck locations) and adapt threshold to reduce false alarms over time.• Energy considerations: Since hydrofoil craft often run on battery, our sonar is designed to be power-efficient (the duty cycle of pings is low, and using solid-state arrays means no moving parts like scanning sonars of old). A typical power draw might be ~50 W for the electronics, which is trivial compared to a propulsion motor, so it's fine.• Fail-safes: The system is add-on and doesn't override manual control except when specifically allowed. Even then, a pilot can always steer or throttle override if they believe necessary (like car ABS or collision avoidance - you can fight it). The system's goal is to assist, not wrest control (unless it's an unmanned craft, then it has full control as programmed).Industrial Applicability

[0081] The disclosure is applicable to the marine and boating industry, especially as the market for fast electric hydrofoils and unmanned surface vessels grows. It can be implemented in new vessel construction or potentially retrofitted to existing hydrofoils with minor modifications (e.g., replacing a section of a strut with an acoustic window panel and embedding a prefab sensor module). Safety regulations in the future might even mandate such systems for passenger hydrofoils after demonstration of their effectiveness (similar to how airplanes have TCAS or cars have collision avoidance).

[0082] According to disclosure, specific use cases includes the following:• Recreational hydrofoil boats and e-foils: giving private boaters an "eye" underwater to avoid hitting rocks or debris in lakes and coastal areas.• Passenger ferries and water taxis: which often foil in cluttered waterways (harbors, rivers) - our system could allow them to maintain speed safely and reduce the need for slow zones.• Coast Guard or naval patrol hydrofoils: enabling high-speed pursuit or patrol at night or in poor visibility - the system could prevent accidents and also allow detection of hazards (like mines or submerged navigation hazards).• Research or survey hydrofoils: e.g., the FoilCart concept - integrating the sonar means they can map seabeds and also avoid collisions, two functions in one.• Autonomous drones: An unmanned hydrofoil drone delivering goods or doing surveillance could use this as its primary sense to avoid collisions with debris or even with divers / animals (with appropriate object classification).

[0083] From a manufacturing standpoint, key components like the transducer arrays can be sourced from sonar component suppliers (many make array elements for fish finders, etc.) and then tailored into the foil mold. The processing can leverage COTS (commercial off-the-shelf) embedded computing (there are even marine-grade GPU boxes that could run our algorithms). The cost of the system is expected to come down with volume, making it feasible even on smaller craft eventually.

[0084] In summary, this disclosure provides a holistic solution to high-speed hydrofoil navigation risk, combining innovations in sensor placement, sonar imaging, and real-time control. It stands clearly apart from prior art by how it achieves the result (flush, non-cavitating integration + beamforming + dynamic corridor mapping) and yields a safer, smarter hydrofoil vessel.

[0085] This disclosure merges advanced sonar tech with hydrofoil design in a novel way that improves safety and enables new capabilities for fast water transport. The foregoing description should enable a variety of implementations without departing from the scope and spirit of the invention, which is defined by the claims that follow. All features of each embodiment can be combined with others as needed; for instance, any described signal processing technique can be applied in any hardware configuration, etc., as would be understood by one skilled in the art.

[0086] According to the disclosure, a hydrofoil watercraft system is disclosed. The system comprises a hydrofoil assembly including at least one strut and at least one wing foil configured to lift a hull of the watercraft at speed, at least one sonar array embedded in a leading portion of the hydrofoil assembly such that an outer surface of the array is substantially flush with an exterior surface of the strut or wing foil, the at least one sonar array including one or more acoustic transmitter elements and a plurality of acoustic receiver elements positioned behind an acoustic window region of the hydrofoil assembly, a sonar transceiver operatively coupled to the sonar array and configured to electronically beam-form and steer an acoustic beam, via said transmitter and receiver elements, to obtain forward-looking sonar data representing a two-dimensional sector of the underwater environment in front of the watercraft, a processing unit configured to receive said sonar data and generate, in real-time while the watercraft is under way at hydrofoiling speed, a navigability corridor analysis indicating an upcoming underwater space sufficient for safe passage of the watercraft or presence of obstacles therein, and to produce an alert or control signal based on the analysis.

[0087] According to the disclosure, the hydrofoil assembly and sonar array are constructed such that no cavitation-inducing structure or gas injection mechanism is present for acoustic noise reduction, the sonar array operating in direct contact with water flow around the hydrofoil assembly. The acoustic window region of the system comprises a flush-mounted acoustic fairing made of a material transparent to the sonar frequency, the fairing forming part of the leading edge of the strut or foil to maintain a smooth hydrodynamic profile over the embedded sonar array.

[0088] According to the disclosure, the sonar array of the system is disposed in a vertical linear arrangement along the strut and configured to beam-form in a horizontal plane ahead of the watercraft, thereby scanning for obstacles within a forward horizontal sector. There sonar array of the system is disposed in a horizontal linear arrangement along the span of the wing foil and configured to beam-form in a vertical plane, thereby scanning a forward vertical slice of the water column to determine underwater free height and bottom profile ahead.

[0089] According to the disclosure, the system further comprises multiple sonar arrays embedded in different portions of the hydrofoil assembly, including at least one in a strut and at least one in a wing, the processing unit configured to combine their respective sonar data to construct a three-dimensional forward view of the underwater environment. The multiple sonar arrays are arranged in mutually orthogonal orientations - one oriented substantially vertically and one substantially horizontally - such that their combined beam-formed data yields a forward-looking 3D image or bathymetry map.

[0090] According to the disclosure, one of the sonar arrays of the system operates as a transmitter-only array and another as a receiver-only array to implement a bistatic forward-looking sonar mode, improving angular coverage or range. The acoustic window region of the system is shaped as a shallow recess or dome in the leading edge and is made of one or more layers selected from: acoustically-transparent composites, elastomeric anti-fouling coatings, or compliant materials that reduce flow noise; and wherein the junction between the acoustic window and the surrounding foil surface is faired to minimize turbulence.

[0091] According to the disclosure, the processing unit of the system is further configured to apply flownoise mitigation algorithms to the received sonar signals, including at least one of: Doppler shift compensation for the watercraft's velocity, adaptive filtering to remove repetitive turbulence noise, timevarying gain adjustments to account for range and absorption, and clutter suppression techniques to ignore returns from bubbles or wake.

[0092] According to the disclosure, the processing unit's navigability corridor analysis comprises calculating a required safe corridor (of a predetermined width and depth) at a certain distance ahead given the watercraft's current speed and trajectory, comparing it to the sonar-detected free space ahead, and if the free space is less than required, automatically generating a control signal to at least one of: (i) command a reduction in throttle, (ii) adjust an auto-pilot or heading to avoid an obstacle, (iii) adjust a height or pitch of the hydrofoil to prepare for a possible collision, and (iv) present a visual or audible warning to the pilot indicating the nature of the hazard.

[0093] According to the disclosure, the system further comprise a human-machine interface (HMI) in communication with the processing unit, the HMI configured to display a real-time forward sonar image or simplified corridor graphic to a pilot, and to indicate safe vs. unsafe corridor regions using distinct visuals (color-coding or similar).

[0094] According to the disclosure, the sonar transceiver of the system is configured to operate multifrequency sonar pulses or chirps, including at least a first frequency band for long-range detection and a second frequency band for higher-resolution short-range imaging, and wherein the processing unit interleaves or alternates these modes to concurrently achieve long-range corridor sensing and detailed imaging of immediate hazards.

[0095] According to the disclosure, the hydrofoil assembly of the system comprises a retractable strut and foil (for example, a foil that can be raised for harbor maneuvering), and the sonar array is installed in a portion of the strut / foil such that it remains submerged and operational when the hydrofoil is deployed; the system further including a connector or wiring mechanism that maintains power / data connection to the sonar array through the range of motion of the retractable foil.

[0096] According to the disclosure, the system comprises an onboard data storage or communication module, wherein the processing unit is configured to log sonar data and event information (obstacle encounters, alerts issued, etc.) and optionally transmit this information to an off-board system or cloud service for further analysis or for updating navigational charts.

[0097] According to the disclosure, the hydrofoil watercraft is an uncrewed surface vessel (USV) or autonomous craft, and the control signal generated by the processing unit is operatively connected to the vessel's autonomy controller such that the vessel can autonomously perform obstacle avoidance maneuvers in real-time based on the forward sonar corridor analysis.

[0098] According to the disclosure, at least one sonar array of the system comprises a plurality of modular transducer units embedded along the foil / strut, each unit having an array of elements and its own local conditioning electronics encapsulated for pressure and impact resistance, and wherein the modular units are networked to the processing unit; such architecture allowing redundant or distributed beamforming (e.g., if one module is damaged, others still operate).

[0099] According to the disclosure, the acoustic transmitter of the system is configured to emit coded waveforms (including frequency-modulated chirps or phase-coded sequences) and the processing unit is configured to perform pulse compression on received signals, thereby improving range resolution and signal-to-noise ratio for detecting small or distant obstacles at high speed.

[0100] According to the disclosure, the processing unit of the system is further programmed with a machine learning model trained to classify sonar returns ahead of the watercraft, distinguishing between different obstacle types or conditions (e.g., differentiating a solid obstacle vs. a patch of floating kelp vs. a school offish) and adjusting the alert / control response accordingly.

[0101] According to the disclosure, the hydrofoil assembly's structural region containing the sonar array is reinforced or adapted to maintain structural strength despite the embedding of the array, including features such as: a stiffening rib around the acoustic window, vibration-isolation mounts that mechanically decouple the transducers from high-frequency foil vibrations, and waterproof potting of electronics to marine standards.

[0102] According to the disclosure, a method for obstacle detection and navigability assessment for a hydrofoil watercraft is disclosed. The method comprising the steps of transmitting an acoustic signal from a sonar array embedded flush within a hydrofoil strut or foil of the watercraft, without deploying any cavitation or air-bubble device, electronically steering a receiver beam of the sonar array across a forward sector ahead of the moving watercraft and collecting echo data from underwater terrain or obstacles, processing the echo data in real-time to construct a forward-range profile or image and to compute a safe navigability corridor ahead based on the dimensions and speed of the watercraft, determining from the computed corridor and profile, whether the watercraft's current path is free of obstacles for a predetermined distance ahead or whether a potential collision / grounding hazard exists, and upon detecting a hazard or insufficient safe corridor, automatically initiating an action comprising atleast one of: issuing an alert to a human operator, logging the event, and / or transmitting a command to the watercraft's control systems to adjust course, speed, or foil position to avoid the hazard.

[0103] According to the disclosure, the step of processing the echo data of the method further comprises applying a thresholding and clustering algorithm to identify free-water regions within the sonar image that meet a minimum depth / width requirement, and designating those regions as part of the navigability corridor, while regions not meeting the requirement are marked as obstacles or unsafe.

[0104] According to the disclosure, the step of transmitting an acoustic signal of the method further comprises emitting a frequency-modulated chirp and step (c) includes correlating received echoes with the transmitted chirp (pulse compression) to improve range resolution, and wherein Doppler processing is also applied to estimate the relative velocity of detected objects (to differentiate stationary seabed vs. moving floating debris, for example).

[0105] According to the disclosure, the sonar array is operated in multiple modes concurrently or sequentially, including a wide-beam shallow mode for broad situational awareness and a narrow-beam focused mode for long-distance look-ahead, and the method includes dynamically adjusting the steering and mode based on the watercraft's speed (e.g., using longer-range mode at higher speeds).

[0106] According to the disclosure, the method further comprises calibrating the sonar array during operation by using known references or combining data from multiple array placements: for example, comparing overlapping fields of view of a strut-embedded array and a foil-embedded array to cross-calibrate angle pointing and ensure the composite corridor analysis is accurate.

[0107] According to the disclosure, the step of initiating an action includes transmitting a control signal that causes an autopilot system to override manual inputs if an immediate collision is imminent, thereby performing an emergency maneuver, and wherein the method defines criteria for such override based on confidence in obstacle detection and time-to-impact.

[0108] According to the disclosure, the method is applied to a plurality of hydrofoil vessels in a network, further comprising each vessel sharing its forward sonar-derived bathymetric and obstacle data with other vessels or a cloud service, thereby collectively mapping hazards in a waterway and enabling anticipatory alerts even for obstacles beyond an individual vessel's immediate sonar range.General Considerations

[0109] Implementations disclosed herein provide systems, methods and apparatus for generating or augmenting training data sets for machine learning training. The functions described herein may be stored as one or more instructions on a processor-readable or computer-readable medium. The term "computer-readable medium" refers to any available medium that can be accessed by a computer or processor. By way of example, and not limitation, such a medium may comprise RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. It should be noted that a computer-readable medium may be tangible and non-transitory. As used herein, the term "code" may refer to software, instructions, code or data that is / are executable by a computing device or processor. A "module" can be considered as a processor executing computer-readable code.

[0110] A processor as described herein can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor can be a microprocessor, but in the alternative, the processor can be a controller, or microcontroller, combinations of the same, or the like. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor may also include primarily analog components. For example, any of the signal processing algorithms described herein may be implemented in analog circuitry. In some embodiments, a processor can be a graphics processing unit (GPU). The parallel processing capabilities of GPUs can reduce the amount of time for training and using neural networks (and other machine learning models) compared to central processing units (CPUs). In some embodiments, a processor can be an ASIC including dedicated machine learning circuitry custom-build for one or both of model training and model inference.

[0111] The disclosed or illustrated tasks can be distributed across multiple processors or computing devices of a computer system, including computing devices that are geographically distributed. The methods disclosed herein comprise one or more steps or actions for achieving the described method.The method steps and / or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is required for proper operation of the method that is being described, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims.

[0112] As used herein, the term "plurality" denotes two or more. For example, a plurality of components indicates two or more components. The term "determining" encompasses a wide variety of actions and, therefore, "determining" can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, "determining" can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, "determining" can include resolving, selecting, choosing, establishing and the like.

[0113] The phrase "based on" does not mean "based only on," unless expressly specified otherwise. In other words, the phrase "based on" describes both "based only on" and "based at least on." While the foregoing written description of the system enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The system should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the system. Thus, the present disclosure is not intended to be limited to the implementations shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

ClaimsWhat is claimed:

1. A hydrofoil watercraft system, comprising:a hydrofoil assembly including at least one strut and at least one wing foil configured to lift a hull of the watercraft at speed;at least one sonar array embedded in a leading portion of the hydrofoil assembly such that an outer surface of the array is substantially flush with an exterior surface of the strut or wing foil, the at least one sonar array including one or more acoustic transmitter elements and a plurality of acoustic receiver elements positioned behind an acoustic window region of the hydrofoil assembly;a sonar transceiver operatively coupled to the sonar array and configured to electronically beam-form and steer an acoustic beam, via said transmitter and receiver elements, to obtain forwardlooking sonar data representing a two-dimensional sector of the underwater environment in front of the watercraft; a processing unit configured to receive said sonar data and generate, in real-time while the watercraft is under way at hydrofoiling speed, a navigability corridor analysis indicating an upcoming underwater space sufficient for safe passage of the watercraft or presence of obstacles therein, and to produce an alert or control signal based on the analysis; andwherein the hydrofoil assembly and sonar array are constructed such that no cavitationinducing structure or gas injection mechanism is present for acoustic noise reduction, the sonar array operating in direct contact with water flow around the hydrofoil assembly.

2. The system of claim 1, wherein the acoustic window region comprises a flush-mounted acoustic fairing made of a material transparent to the sonar frequency, the fairing forming part of the leading edge of the strut or foil to maintain a smooth hydrodynamic profile over the embedded sonar array.

3. The system of claims 1 or 2, wherein the sonar array is disposed in a vertical linear arrangement along the strut and configured to beam-form in a horizontal plane ahead of the watercraft, thereby scanning for obstacles within a forward horizontal sector.

4. The system of claims 1 or 2, wherein the sonar array is disposed in a horizontal linear arrangement along the span of the wing foil and configured to beam-form in a vertical plane, thereby scanning a forward vertical slice of the water column to determine underwater free height and bottom profile ahead.

5. The system of claim 1, further comprising multiple sonar arrays embedded in different portions of the hydrofoil assembly, including at least one in a strut and at least one in a wing, the processing unit configured to combine their respective sonar data to construct a three-dimensional forward view of the underwater environment.

6. The system of claim 5, wherein the multiple sonar arrays are arranged in mutually orthogonal orientations - one oriented substantially vertically and one substantially horizontally - such that their combined beam-formed data yields a forward-looking 3D image or bathymetry map.

7. The system of claims 5 or 6, wherein one of the sonar arrays operates as a transmitter-only array and another as a receiver-only array to implement a bistatic forward-looking sonar mode, improving angular coverage or range.

8. The system of claim 1, wherein the acoustic window region is shaped as a shallow recess or dome in the leading edge and is made of one or more layers selected from: acoustically-transparent composites, elastomeric anti-fouling coatings, or compliant materials that reduce flow noise; and wherein the junction between the acoustic window and the surrounding foil surface is faired to minimize turbulence.

9. The system of claim 1, wherein the processing unit is further configured to apply flow-noise mitigation algorithms to the received sonar signals, including at least one of: Doppler shift compensation for the watercraft's velocity, adaptive filtering to remove repetitive turbulence noise, time-varying gain adjustments to account for range and absorption, and clutter suppression techniques to ignore returns from bubbles or wake.

10. The system of claim 1, wherein the processing unit's navigability corridor analysis comprises calculating a required safe corridor (of a predetermined width and depth) at a certain distance ahead given the watercraft's current speed and trajectory, comparing it to the sonar-detected free space ahead, and if the free space is less than required, automatically generating a control signal to at least one of: (i) command a reduction in throttle, (ii) adjust an auto-pilot or heading to avoid an obstacle, (iii) adjust a height or pitch of the hydrofoil to prepare for a possible collision, and (iv) present a visual or audible warning to the pilot indicating the nature of the hazard.

11. The system of claim 1, further comprising a human-machine interface (HMI) in communication with the processing unit, the HMI configured to display a real-time forward sonar image or simplified corridor graphic to a pilot, and to indicate safe vs. unsafe corridor regions using distinct visuals (color-coding or similar).

12. The system of claim 1, wherein the sonar transceiver is configured to operate multi-frequency sonar pulses or chirps, including at least a first frequency band for long-range detection and a second frequency band for higher-resolution short-range imaging, and wherein the processing unit interleaves or alternates these modes to concurrently achieve long-range corridor sensing and detailed imaging of immediate hazards.

13. The system of claim 1, wherein the hydrofoil assembly comprises a retractable strut and foil (for example, a foil that can be raised for harbor maneuvering), and the sonar array is installed in a portion of the strut / foil such that it remains submerged and operational when the hydrofoil is deployed; the system further including a connector or wiring mechanism that maintains power / data connection to the sonar array through the range of motion of the retractable foil.

14. The system of claim 1, further comprising an onboard data storage or communication module, wherein the processing unit is configured to log sonar data and event information (obstacle encounters, alerts issued, etc.) and optionally transmit this information to an off-board system or cloud service for further analysis or for updating navigational charts.

15. The system of claim 1, wherein the hydrofoil watercraft is an uncrewed surface vessel (USV) or autonomous craft, and the control signal generated by the processing unit is operatively connected to the vessel's autonomy controller such that the vessel can autonomously perform obstacle avoidance maneuvers in real-time based on the forward sonar corridor analysis.

16. The system of claim 1, wherein the at least one sonar array comprises a plurality of modular transducer units embedded along the foil / strut, each unit having an array of elements and its own local conditioning electronics encapsulated for pressure and impact resistance, and wherein the modular units are networked to the processing unit; such architecture allowing redundant or distributed beamforming (e.g., if one module is damaged, others still operate).

17. The system of claim 1, wherein the acoustic transmitter is configured to emit coded waveforms (including frequency-modulated chirps or phase-coded sequences) and the processing unit is configured to perform pulse compression on received signals, thereby improving range resolution and signal-to-noise ratio for detecting small or distant obstacles at high speed.

18. The system of claim 1, wherein the processing unit is further programmed with a machine learning model trained to classify sonar returns ahead of the watercraft, distinguishing between different obstacle types or conditions (e.g., differentiating a solid obstacle vs. a patch of floating kelp vs. a school of fish) and adjusting the alert / control response accordingly.

19. The system of Claim 1, wherein the hydrofoil assembly's structural region containing the sonar array is reinforced or adapted to maintain structural strength despite the embedding of the array, including features such as: a stiffening rib around the acoustic window, vibration-isolation mounts that mechanically decouple the transducers from high-frequency foil vibrations, and waterproof potting of electronics to marine standards.

20. A method for obstacle detection and navigability assessment for a hydrofoil watercraft, the method comprising the steps of:transmitting an acoustic signal from a sonar array embedded flush within a hydrofoil strut or foil of the watercraft, without deploying any cavitation or air-bubble device;electronically steering a receiver beam of the sonar array across a forward sector ahead of the moving watercraft and collecting echo data from underwater terrain or obstacles;processing the echo data in real-time to construct a forward-range profile or image and to compute a safe navigability corridor ahead based on the dimensions and speed of the watercraft;determining, from the computed corridor and profile, whether the watercraft's current path is free of obstacles for a predetermined distance ahead or whether a potential collision / grounding hazard exists; andupon detecting a hazard or insufficient safe corridor, automatically initiating an action comprising at least one of: issuing an alert to a human operator, logging the event, and / or transmitting a command to the watercraft's control systems to adjust course, speed, or foil position to avoid the hazard.

21. The method of claim 20, wherein the step of processing the echo data further comprises applying a thresholding and clustering algorithm to identify free-water regions within the sonar image that meet a minimum depth / width requirement, and designating those regions as part of the navigability corridor, while regions not meeting the requirement are marked as obstacles or unsafe.

22. The method of claim 20, wherein the step of transmitting an acoustic signal further comprises emitting a frequency-modulated chirp and step (c) includes correlating received echoes with the transmitted chirp (pulse compression) to improve range resolution, and wherein Doppler processing is also applied to estimate the relative velocity of detected objects (to differentiate stationary seabed vs. moving floating debris, for example).

23. The method of claim 20, wherein the sonar array is operated in multiple modes concurrently or sequentially, including a wide-beam shallow mode for broad situational awareness and a narrow-beam focused mode for long-distance look-ahead, and the method includes dynamically adjusting the steering and mode based on the watercraft's speed (e.g., using longer-range mode at higher speeds).

24. The method of claim 20, further comprising calibrating the sonar array during operation by using known references or combining data from multiple array placements: for example, comparing overlapping fields of view of a strut-embedded array and a foil-embedded array to cross-calibrate angle pointing and ensure the composite corridor analysis is accurate.

25. The method of claim 20, wherein the step of initiating an action includes transmitting a control signal that causes an autopilot system to override manual inputs if an immediate collision is imminent, thereby performing an emergency maneuver, and wherein the method defines criteria for such override based on confidence in obstacle detection and time-to-impact.

26. The method of claim 20, applied to a plurality of hydrofoil vessels in a network, further comprising each vessel sharing its forward sonar-derived bathymetric and obstacle data with other vessels or a cloud service, thereby collectively mapping hazards in a waterway and enabling anticipatory alerts even for obstacles beyond an individual vessel's immediate sonar range.

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