METHOD FOR AID IN GUIDING A SURFACE VESSEL INTENDED TO TOW A SUBWATER DEVICE BY MEANS OF A CABLE

Abstract

The invention relates to a method for assisting the guidance of a surface vessel (10) intended to tow a subsea device, the method comprising: a) a discretization of the geographical sector (21) around the surface vessel (10) into a plurality of zones (22, 23), each zone (22, 23) being classified according to a degree of accessibility among a set of degrees of accessibility; b) a calculation of a set of candidate trajectories (24, 25, 26) of the surface vessel (10) in said geographical sector (21), each candidate trajectory (24, 25, 26) corresponding to a different rate of rotation from the current position of the surface vessel (10); c) a ranking of each candidate trajectory (24, 25, 26) according to the degree of accessibility of the area of ​​the geographical sector crossed by the possible trajectory (24, 25, 26), and according to the feasibility of one or more predefined actions on said candidate trajectory (24, 25, 26);d) generating a display of the zones (22, 23) and candidate trajectories (24, 25, 26) on a human-machine interface, according to their classification and / or transmitting instructions relating to said actions. Figure for the abbreviation: Fig. 4;

Description

Title of the invention: METHOD FOR AID IN GUIDING A SURFACE VESSEL INTENDED TO TOW A SUBMARINE DEVICE BY MEANS OF A CABLE technical field

[0001] The invention relates generally to the field of surface vessel guidance, and in particular to a surface vessel towing a submerged body, or underwater device, via a cable.

[0002] The underwater device may typically include a variable depth sonar, intended for underwater detection measurements, or any other device operating while submerged.

[0003] When a surface vessel, such as a ship, tows an underwater device at a certain speed, the device tends to rise towards the surface. This occurs particularly when the tow cable is not sheathed. The cable can then be much longer than both the immersion depth of the underwater device and the water depth.

[0004] In such a case, the exact depth of the underwater device cannot be determined with certainty. The haul cable may adopt an elongated "S" shaped profile, but many other profiles are possible.

[0005] In general, during rotation, the underwater device tends to descend and approach the seabed, which poses a danger to the underwater device. At high speed, the underwater device initially loses altitude before rising slightly.

[0006] Therefore, to reach a certain immersion depth, it is always necessary to allow a significant margin when unwinding the haul rope.

[0007] However, it is essential that the underwater device does not collide with the seabed, which could damage it.

[0008] Currently, known solutions are used based on nomograms, but these require allowing for large margins. These nomograms indicate the depth of the underwater device as a function of the length of cable deployed, for different surface vessel speeds.

[0009] Such an approach offers little flexibility and is relatively cumbersome to implement, which can lead to risks if navigation parameters change rapidly.

[0010] Furthermore, the application of numerous margins prevents navigation of the surface building with the towed vehicle in areas which do not present any risk of collision with the seabed.

[0011] Another known solution, described in document JP2005193767A, proposes a depth control device for an underwater device, which calculates the value of an upper altitude limit function, and the value of a lower altitude limit function, obtained by adding margins to the topographic data.

[0012] A potential intersection with an obstacle is calculated using the value of the upper altitude limit function, and the value of the lower altitude limit function, and the depth of the underwater device is corrected in case of detection of a potential intersection.

[0013] However, such a device uses a database of characteristics in response from the underwater device, which corresponds to the previously mentioned charts, and is therefore not very flexible.

[0014] There is therefore a need for improved guidance aid processes and systems. Summary of the invention

[0015] The invention aims to remedy the aforementioned drawbacks by proposing a flexible and easy-to-use method.

[0016] An object of the invention is therefore a method for assisting the guidance of a surface vessel intended to tow an underwater device by means of a towing cable, the method comprising: a) a discretization of the geographical sector around the surface building into a plurality of zones, each zone being classified according to a degree of accessibility among a set of degrees of accessibility, depending on the bathymetry of the geographical sector and current navigation parameters of the surface building including the length of the haul rope; b) a calculation of a set of candidate trajectories of the surface building in said geographical sector, each candidate trajectory corresponding to a different rate of rotation from the current position of the surface building; c) a ranking of each candidate trajectory according to the degree of accessibility of the area of ​​the geographical sector crossed by the possible trajectory, and according to the feasibility of one or more predefined actions on said candidate trajectory; d) a generation of a display of candidate zones and trajectories on a human-machine interface, according to their classification and / or a transmission of instructions relating to said actions.

[0017] Advantageously, each zone has a minimum margin depth, said minimum margin depth of each zone being calculated from the minimum depth of all zones located within a predefined radius around said zone, and the underwater device has a current depth and in which the set of degrees of accessibility includes: - a first degree of accessibility if the minimum margined depth of the area is greater than or equal to the sum between a vertical protection margin of the underwater device and the current depth of the underwater device, said current depth of the underwater device being calculated as a function of the length of the haul rope and the speed of the surface vessel; - a second degree of accessibility if the minimum margin depth of the area is strictly less than said sum between the vertical protection margin of the underwater device and the current depth of the underwater device, and if the minimum margin depth of the area is greater than or equal to the protection margin of the underwater device; - a third degree of accessibility if the minimum margined depth of the area is strictly less than the vertical protection margin of the underwater device.

[0018] Advantageously, a first zone appearance parameter, a second zone appearance parameter and a third zone appearance parameter are respectively assigned to the first level of accessibility, the second level of accessibility and the third level of accessibility.

[0019] Advantageously, the first zone appearance parameter, the second zone appearance parameter and the third zone appearance parameter correspond to different colors.

[0020] Advantageously, each candidate trajectory is sampled at a plurality of equidistant points, and in which, at each point, starting from the first point of the candidate trajectory, is assigned: - a first trajectory appearance parameter if said first trajectory appearance parameter has been assigned to the previous point and if the estimated depth of the underwater device is less than the sum of the minimum depth margin of the area and the vertical protection margin of the underwater device, the estimated depth of the underwater device being calculated as a function of the length of the haul rope, the speed of the surface vessel and the rate of turn corresponding to the candidate trajectory on which the point is located; - a second trajectory appearance parameter if the corrected estimated depth of the underwater device is less than the sum of the minimum margined depth and the vertical protection margin of the underwater device, the corrected estimated depth of the underwater device being calculated based on the length of the tow cable, the speed of the surface vessel, and the corresponding rate of turn the candidate trajectory on which the point is located, and one or more predefined actions on said candidate trajectory, the second trajectory appearance parameter also being assigned to the following points of the candidate trajectory; - a third trajectory appearance parameter if gyration of the candidate trajectory is impossible given the length of the haul rope, or if gyration is impossible given the speed of the surface building, the third trajectory appearance parameter being further also assigned to the following points of the candidate trajectory.

[0021] Advantageously, the first trajectory appearance parameter, the second trajectory appearance parameter and the third trajectory appearance parameter correspond to different colors.

[0022] Advantageously, the method further includes a step of correcting the vertical protection margin of the underwater device, and / or a step of correcting the predefined radius used in the calculation of the minimum margined depth.

[0023] Advantageously, said predefined actions include an action to raise the underwater device and / or an action to accelerate the surface vessel.

[0024] Advantageously, the feasibility of one or more predefined actions on said candidate trajectory is calculated by taking into account the time to carry out the action before the arrival of the surface building in an area classified according to a degree of accessibility different from the area corresponding to the current position of the surface building.

[0025] Advantageously, the step of generating a display of each possible trajectory includes generating a display of the trajectory in the form of an arc of a circle passing through a point representing the surface building, or in the form of a segment aligned with the point representing the heading of the surface building.

[0026] Advantageously, steps a) to d) are repeated periodically.

[0027] Advantageously, the method includes, in response to the selection by the user of one of the points located on the representation of one of the candidate trajectories generated on the human-machine interface, a simulation step of steps a) to d), considering that the surface building is fictitiously positioned at the level of said point.

[0028] The invention also relates to a computer program product, comprising instructions for the execution of the predefined process when the program is executed by a processor.

[0029] The invention also relates to a guidance aid system for a surface vessel intended to tow an underwater device by means of a tow cable, the system comprising: - A computing device comprising: — a discretization unit, configured to discretize the geographic sector around the surface building into a plurality of zones, each zone being classified according to a degree of accessibility among a set of degrees of accessibility, based on current navigation parameters of the surface building including the length of the haul rope; — a first calculation unit, configured to calculate a set of candidate trajectories of the surface building in said geographical sector, each candidate trajectory corresponding to a different rate of rotation from the current position of the surface building; — a classification unit, configured to classify each candidate trajectory according to the degree of accessibility of the area of ​​the geographical sector crossed by the possible trajectory, and according to the feasibility of one or more predefined actions on said candidate trajectory; - A human-machine interface configured to generate a display of candidate zones and trajectories based on their classification and / or to transmit instructions relating to said actions.

[0030] Advantageously, the underwater device includes a sonar. Description of the figures

[0031] Other features, details and advantages of the invention will become apparent from the description made with reference to the accompanying drawings given by way of example.

[0032] Fig. 1 illustrates a surface vessel towing an underwater device.

[0033] Figure 2 illustrates a flowchart representing the method of assisting guidance of the invention.

[0034] Fig. 3 illustrates a discretization step of the geographical sector around the surface building into a plurality of zones.

[0035] Fig. 4 is a diagram representing an example of displaying areas and possible trajectories on a human-machine interface.

[0036] Figure 5 illustrates a step of calculating a set of candidate trajectories, as well as a step of ranking the different possible trajectories.

[0037] Fig. 6 is a diagram of a computer architecture implementing the process, according to embodiments of the invention. Detailed description

[0038] Fig. 1 represents an example of a surface vessel 10 towing an underwater device 11.

[0039] In some embodiments, the underwater device 11 is an active sonar comprising an acoustic transmitting antenna 12, also called a "fish" and an acoustic receiving antenna 13, also called a "flute".

[0040] The surface building 10 includes at least one haul cable 14 configured to haul the two antennas 12 and 13. The haul cable 14 also provides the transmission of signals and power supplies between the surface building 10 and the sonar antennas 12 and 13.

[0041] In one embodiment, the surface building 10 may comprise two separate haul ropes connected directly to the surface building 10 (the so-called independent mode). In another, so-called dependent mode, the first rope, connected to the surface building 10, is configured to haul the fish 12, and the second rope is configured to haul the flute 13, the second rope hauling the flute then being attached to the fish 12.

[0042] To facilitate understanding of the invention, the following description of embodiments of the invention will be made primarily with reference to a single haul rope 14, by way of non-limiting example. The method can be generalized to a surface building 10 comprising a plurality of haul ropes.

[0043] The antennas 12 and 13 can be mechanically attached and connected electrically and / or optically to the haul rope 14 in a suitable manner. The receiving antenna 13 is formed of a linear antenna with a tubular shape (hence its name "flute"), while the transmitting antenna 12 is integrated into a volumetric structure having a shape resembling that of a fish (hence the name "fish").

[0044] The receiving flute 13 can be disposed at the rear, at the level of the end of the cable 14, while the fish 12 is positioned on the part of the cable 14 closest to the surface building 10.

[0045] The underwater device 11 can be used to perform underwater acoustic missions.

[0046] During an underwater acoustics mission, the antenna 12 is configured to emit sound waves in the water and the receiving antenna 13 is configured to capture possible echoes from targets on which the sound waves from the antenna 12 are reflected.

[0047] The launching and retrieval of the underwater device 11 can be carried out by means of a winch 16 located on a deck 17 of the surface vessel 10. The winch 16 may include a reel 18 sized to allow the winding of the cable 14 as well as the receiving antenna 13.

[0048] The winch 16 may also include a frame for mounting on the ship's deck. The reel 18 is capable of pivoting relative to the frame to allow the cable to be wound. Winding the cable 14 allows the fish 12 to be hauled aboard the surface vessel 10, for example onto a rear platform 19 provided for this purpose.

[0049] The underwater device may include a fairlead 20 configured to guide the cable 14 downstream of reel 18. The fairlead 20 constitutes the last guiding element of cable 14 before its descent into the water.

[0050] Embodiments of the invention provide a method for assisting the guidance of the surface vessel 10 intended to tow the underwater device 11 via the towing cable 14.

[0051] The guidance assistance method according to the embodiments of the invention can be implemented in a device located in the surface building 10, or in a simulator.

[0052] The [Fig. 1] is a flowchart representing the guidance aid method according to embodiments of the invention.

[0053] In step 100, the geographical area around the surface building is divided into a plurality of zones, each zone being characterized by positional data. According to certain embodiments, the geographical area around the surface building corresponds to a circle of predefined radius, centered on the surface building 10.

[0054] In one embodiment, illustrated by [Fig. 3], step 100 includes prior determination of navigation parameters relating to the surface vessel, for example by means of measurements (101). The navigation parameters may include: - a first parameter representing the current speed of the surface vessel 10 (current speed) determined at a current time. The current speed of the surface vessel 10 can be measured, for example, using a speed indicator, or by means of a navigation device on board the surface vessel 10; - the length of cable drawn (i.e., unspooled) at the current time. In one embodiment, the winch 16 can be equipped with a measuring instrument configured to determine the length of cable drawn, for example by determining the angle of rotation of the winch 16.

[0055] The function that links the navigation parameters to the estimated immersion depth is called the "flight domain". The "flight domain" function is stored by a processing unit during step 102.

[0056] In step 103, the current depth of the underwater device 11, at any point in the geographical sector, is calculated from the navigation parameters and the function indicating the flight domain.

[0057] In one embodiment, the calculation 103 can be implemented using a computer embedded in the surface building 10, for example as a client application in the onboard computer of the surface building 10.

[0058] In some embodiments, the calculation step 103 may further take into account parameters relating to the behavior of the underwater device 11, in its flight envelope, such as for example: - a parameter indicating whether the underwater device links positive buoyancy or negative - a parameter indicating whether the underwater device 11 is ascending or descending, and / or - a parameter indicating whether the underwater device 11 has variable wings that can be controlled or servo-controlled according to the traction force.

[0059] Furthermore, the calculation step 103 can use bathymetric data 104, namely topographic surveys of underwater reliefs, which constitute a map of a digital terrain model of the geographical area around the surface building 10.

[0060] In step 100, the geographic sector is discretized into a plurality of zones, the size of which can be adjusted. Each zone (22, 23 in [Fig.4]) can be represented by a predefined number of pixels, constituting a given and constant shape from one zone to another, such as a square.

[0061] The zones are sized so that the relevant information is visible to the naked eye by the user, while providing a sufficiently fine segmentation of the geographical area.

[0062] Discretizing the geographical sector thus provides a mosaic of zones, the position of which is determined by coordinates (x, y) in the frame of reference of [Fig.4]. For each of the zones, it is possible to determine the most unfavorable passage point for the underwater device 11, namely the minimum depth of the zone.

[0063] As used here, the "minimum depth" refers, for a given area, to the depth of the highest point in the area, in absolute altitude (along the z-axis, [Fig. 4]). The minimum depth for each area of ​​the geographical sector can be calculated and stored in memory in step 104.

[0064] According to an advantageous embodiment, a minimum margin depth can be calculated for each zone, based on the minimum depth of all zones located within a predefined radius around said zone (step 104'). The calculation of the minimum margin depth thus makes it possible to take into account "horizontal" uncertainties, i.e., those related to the position of the surface vessel 10 and / or the underwater device 11.

[0065] For example, for a predefined radius equal to one nautical mile, for each point (or area) of the map, a disk of radius equal to one nautical mile is centered on the point, then the point which has the minimum depth in the disk is determined.

[0066] This minimum depth in the vicinity of any point makes it possible to construct a so-called "dual" bathymetry, that is, a bathymetry that includes an additional horizontal margin. The predefined radius can have a default value and / or be adjustable by the user.

[0067] The calculation of dual bathymetry, which can consume a lot of information resources- matics, can be carried out in advance of the mission.

[0068] In step 105, the vertical immersion margin of the underwater device 11 is retrieved from a memory location. The vertical immersion (or protection) margin of the underwater device 11 corresponds to a vertical protection margin of the underwater device 11. The vertical protection margin can take a default value, provided for example by the manufacturer of the underwater device 11, and can then be adjusted.

[0069] The margin of protection allows for taking into account the slight, difficult-to-control displacements of the underwater device 11 when it is submerged, which may themselves depend, in part, on the structural characteristics of the underwater device 11, as well as on sea currents.

[0070] In step 106, each zone within the entire geographical sector can be classified according to a degree of accessibility associated with the zone and representing the level of accessibility of the zone. The entire bathymetry 104 of the whole geographical sector can be taken into account to determine the level of accessibility of the surface vessel 10 towing the underwater device 11, and not just a few isobaths.

[0071] Figure 4 illustrates an example of classifying zones according to their degree Accessibility. In some embodiments, a zone appearance parameter can be associated with each zone based on its degree of accessibility. The zone appearance parameter can be associated with a given zone if the zone is accessible by the surface vessel without the submersible device 11, taking into account the current cable deployment, reaching the minimum depth of the zone, considering the immersion margins. This is the case, for example, for zone 23 in [Fig. 4].

[0072] In one embodiment, the first level of accessibility satisfies the following condition (1):

[0073] Pmin>M + Pc(l)

[0074] In equation (1), the parameter Pmin designates the minimum margin depth of the zone, the parameter M designates the vertical protection margin of the underwater device 11, and the parameter Pc designates the current depth of the underwater device 11.

[0075] The current depth of the underwater device can be calculated as a function of the length of the haul rope and the speed of the surface vessel.

[0076] For example, it is possible to define the parameters of the function that provides the current depth of the underwater device 11 by means of empirical measurements carried out during a calibration phase of the process.

[0077] For example, it is possible to measure the actual depth for different values ​​of the cable's length and for different surface building speeds. In some embodiments, the actual depth can be measured using pressure sensors.

[0078] On [Fig.4], it can be noted that certain areas having the same degree of accessibility are represented contiguously, the classification of the areas being carried out area by area.

[0079] According to one embodiment, a first zone appearance parameter is assigned to the first level of accessibility. The zone appearance parameter can be, for example, a color parameter, such as the color green. The zone having a first level of accessibility can be colored, for example, green.

[0080] A second degree of accessibility can be used to characterize the area if, taking into account the current speed of the surface vessel 10 and the length of the tow cable 14, a collision of the underwater device 11 with the seabed is likely to occur, also taking into account the immersion margin. This is the case, for example, of area 22 in [Fig. 4].

[0081] In one embodiment, the second level of accessibility satisfies the following condition (2):

[0082] Pmin < M + Pc and Pmin > M (2)

[0083] According to one embodiment, a second zone appearance parameter is assigned to the second level of accessibility. The zone appearance parameter can be, for example, a color parameter, such as the color orange. The zone having a second level of accessibility can be colored, for example, orange.

[0084] In one embodiment, a third level of accessibility can be used if the minimum depth of the area is strictly less than the protection margin of the underwater device. This corresponds to the case where, regardless of the length of cable 14 deployed, the device 11 cannot respect the immersion margins. This scenario may arise, for example, if a landform is located in an emerged part of the geographical area. Figure 4 does not illustrate this situation.

[0085] The following condition (3) must therefore be satisfied for the third level of accessibility:

[0086] Pmin <M(3)

[0087] According to one embodiment, a third zone appearance parameter is assigned to the third level of accessibility. The zone appearance parameter can be, for example, a color parameter, such as the color red. The zone having a third level of accessibility can be colored, for example, with the color red.

[0088] The value of the protection margin can be modified and the impact of this change in value can be visualized at the level of the change in appearance (color for example) of certain areas on the human-machine interface.

[0089] Such a change in values ​​makes it possible to extend the navigation area, by relaxing the constraint on the protection margin (vertical and / or horizontal) of the underwater device 11.

[0090] This visualization mode by zone and by degree of accessibility offers a good view of the possible developments for the surface building 10.

[0091] In embodiments where the zone appearance parameters are color parameters, the degrees of accessibility can be distinguished based on the color parameters. In one embodiment, the color parameters may be shades of gray, for example black, gray, and white.

[0092] In other embodiments, the zone appearance parameters may be different patterns for different degrees of accessibility.

[0093] Fig. 5 represents the other calculation steps 200, 300 and 400 of the guidance aid method according to embodiments of the invention.

[0094] In the second calculation step 200, a set of candidate trajectories (for example, trajectories 24, 25, 26 of [Fig.4]) of the surface building 10 in the geographical sector 21 are calculated in step 202, based on navigation parameters obtained in step 201.

[0095] The starting point of each of the candidate trajectories corresponds to the current location of the building with surface area 10 and continues substantially in the form of a circular arc, over a predefined length. The value of the chord, for each circular arc, is increasing. The modeling of such trajectories therefore presents no computational complexity.

[0096] Although it is always possible that the surface building 10 may ultimately take a trajectory that does not exactly correspond to one of the candidate trajectories shown, the sufficiently high number of candidate trajectories shown on the human-machine interface makes it possible to provide a considerable number of navigation options, depending on their feasibility.

[0097] One of the candidate trajectories corresponds to a segment which starts from the location of the surface building 10 and is aligned with its heading.

[0098] Each of the candidate trajectories thus corresponds to a different rate of turn of the surface vessel 10. The rate of turn corresponds to the speed at which the surface vessel 10 changes course as well as the direction of its change of course (port or starboard).

[0099] The rate of rotation can also be called the "speed of rotation". In reality, the rate of rotation is the speed of rotation of the surface building, in degrees per minute (7 min).

[0100] It can be calculated either from the variation in heading, or from the formula below, with a radius of gyration extrapolated from the successive positions of the ship (units are in italics):

[0101] Rotation rate (° / min) = 360 / Revolution_time(mm) = 360*Speed(m / mm) / (2*Pi*Radius_of_gyration(m)) = 360*60*1852 / (2*Pi*3600)*Speed(knots) ) / Radius_of_gyration(m) = 5556 / Pi* Speeds se(node60 / Radius_of_gyration(m)

[0102] Referring again to [Fig. 4], eleven candidate trajectories are shown: one candidate trajectory 26 corresponding to a zero rate of turn, five port trajectories with different rates of turn, and five starboard trajectories with different rates of turn (for example, trajectories 24 and 25 in [Fig. 4]). Of course, the number of candidate trajectories can be parameterized differently.

[0103] The different candidate trajectories can be determined and then saved in a memory area.

[0104] In a third step 300, each candidate trajectory (24, 25, 26) can be classified according to the degree of accessibility of the area of ​​the geographical sector crossed by the possible trajectory (24, 25, 26), and according to the feasibility of one or more predefined actions on said candidate trajectory (24, 25, 26).

[0105] In a step 301, the extended gyration domain is calculated. It corresponds to the flight domain calculated in step 102, refined with the additional parameter of the surface building's gyration rate 10.

[0106] For each candidate trajectory, the estimated depth of the underwater device 11 can be calculated in step 303 as a function of the speed of the surface vessel 10, assumed to be constant from the current position of the surface vessel 10, the length of the haul rope unwound, also assumed to be constant from the current position of the surface vessel 10, and the rate of rotation on the candidate trajectory.

[0107] The unspooled length of the haul rope corresponds to the length of cable unspooled out of the winch.

[0108] We define a positive real function f which takes as input three positive parameters (Stretched length, speed, radius of gyration) and returns the estimated depth of the underwater device 11.

[0109] Regardless of L1, L2, VI, V2, RI and R2 taken from the physically attainable parameters of the surface building 10 (limited by the cable length, the maximum speed of the surface building 10 and its minimum turning radius):

[0110] ifLl = 0 then f(Ll,Vl,Rl) = 0 [YES] if VI = 0 then f(Ll,Vl,Rl) = Ll

[0112] ifLl < L2 then f(Ll,Vl,Rl) <f(L2,Vl,Rl)

[0113] if VI < V2 then f(Ll,Vl,Rl) > f(Ll,V2,Rl)

[0114] if RI < R2 then f(Ll,Vl,Rl) > f(Ll,Vl,R2)

[0115] For example, it is possible to define the parameters of the function which provides the estimated depth of the underwater device 11 by means of empirical measurements carried out during a calibration phase of the process.

[0116] It is possible, for example, to measure the actual depth for different values The surface building speed is measured at 10, for different lengths of the haul rope deployed, and for different rotation rates. In some embodiments, the actual depth can be measured using pressure sensors.

[0117] Other parameters can also be taken into account, such as the behavior parameter(s) of the underwater device 11 in its flight domain, indicating whether the device has positive or negative buoyancy, whether it is rising or diving, or whether it has variable wings that can be controlled or servo-controlled according to the traction effort.

[0118] The depth of the underwater device 11 can thus be calculated at any point of the candidate trajectory.

[0119] The ranking of each candidate trajectory can also be established based on the feasibility of one or more predefined actions on each of the candidate trajectories (302). The predefined actions are mechanical actions or maneuvers that can be performed to raise the underwater device 11 to the surface of the water. In one embodiment, the actions may include: - a potential acceleration of the building by surface area 10, from its current position, before reaching a point that corresponds to the transition from a first-degree accessibility zone to a second-degree accessibility zone; and / or - an action consisting of pulling back a length of traction cable 14 (winding action) before reaching a point which corresponds to the passage from a first degree accessibility zone to a second degree accessibility zone.

[0120] These two actions can be undertaken simultaneously, i.e. by simultaneously accelerating the surface building 10 and winding the traction cable 14, or successively.

[0121] From bathymetric data (block 305) and dual bathymetric data (block 305'), the feasibility of one or more predefined actions, and the estimated depth on the candidate trajectory, in step 304, the vertical and horizontal immersion (or protection) margins are calculated, and each of the candidate trajectories according to one or the other of the appearance characteristics can be classified.

[0122] In a preferred embodiment, the feasibility of one or more predefined actions on the candidate trajectory can be calculated by taking into account the time to perform the action (time taken to perform the action) before the arrival of the surface building 10 in an area classified according to a degree of accessibility different from the area corresponding to the current position of the surface building 10.

[0123] Thus, if the candidate trajectory passes through a first-degree accessibility zone and then through a second-degree accessibility zone, corrective actions can be carried out before the surface building passes from the first-degree accessibility zone to the second-degree accessibility zone.

[0124] In a fourth step 400, a display of the zones (22, 23) and candidate trajectories (24, 25, 26) is generated on a human-machine interface, based on the ranking of the trajectories. The method may further include a step for transmitting instructions relating to predefined actions (for example, raising the underwater device 11, accelerating the surface vessel 10).

[0125] The display of candidate trajectories and the transmission of instructions can be generated simultaneously on the same screen of the human-machine interface. For example, in response to an operator (e.g., a navigation operator) pointing to a candidate trajectory using a cursor, instructions can be displayed in a window and disappear when the cursor is no longer positioned on the trajectory (a "pop-up" display, or contextual window).

[0126] Alternatively, a display of all instructions can appear permanently, in a secondary window, next to the navigation map.

[0127] According to another variant, the instructions can be provided in the form of an audio message.

[0128] The embodiments thus make it possible to generate an optimized display allowing visualization of the trajectory to be taken, without requiring additional action, the trajectories requiring specific maneuvers, and the impossible trajectories.

[0129] In an alternative embodiment, only instructions can be transmitted, at the end of the aforementioned steps 100, 200, and 300. According to another variant, the candidate zones and trajectories can be displayed according to their ranking, without any specific instructions being added; the operator can determine, using their expertise, the actions to be implemented.

[0130] Different trajectory appearance parameters can be used to distinguish the rankings of candidate trajectories. Appearance parameters can be, for example, color parameters. For a black and white or grayscale human-machine interface, appearance characteristics can correspond to different line thicknesses or different patterns.

[0131] For each candidate trajectory, the coordinates of the points separated by a predefined distance can be calculated in the aforementioned frame (see [Fig.4]), so as to establish a sampling of the candidate trajectory.

[0132] The coordinates may be expressed in the geodetic system of the map, for example the WGS84 geodetic system, used in particular by the GPS satellite positioning system. Any other geodetic system may also be suitable.

[0133] Each candidate trajectory is thus made up of a set of equidistant points (for example, points 27 on [Fig. 4]). The distance between each point can vary depending on the length of the candidate trajectory, or be fixed, regardless of the length of the candidate trajectory.

[0134] Calculating on a limited number of points, due to sampling, and on an easily modelable trajectory (an arc of a circle), reduces the computational complexity of the guidance process, making it compatible with real-time applications.

[0135] For each point, starting from the first point of the candidate trajectory, a first trajectory appearance parameter can be assigned to the candidate trajectory if the estimated depth of the underwater device is less than the sum of the minimum depth margin of the area and the vertical protection margin of the underwater device. The first trajectory appearance parameter must then also be assigned to the preceding point.

[0136] A second trajectory appearance parameter may be assigned if, for at least one point of the candidate trajectory, the corrected estimated depth of the underwater device is less than the sum of the minimum margined depth and the vertical protection margin of the underwater device.

[0137] The corrected estimated depth of the underwater device 11 is calculated as a function of the length of the haul rope 14, the speed of the surface vessel 10, the rate of rotation corresponding to the candidate trajectory (24, 25, 26) on which the point is located, and one or more predefined actions on said candidate trajectory.

[0138] The second trajectory appearance parameter is also assigned to subsequent points of the candidate trajectory. Thus, points of a candidate trajectory cannot have a first trajectory appearance parameter if the preceding points, namely those located closest to the surface building 10, have a second trajectory appearance parameter.

[0139] Thus, according to embodiments of the invention, a candidate trajectory has a first appearance parameter if the first appearance parameter is assigned to all points of the candidate trajectory, and a candidate trajectory has a second appearance parameter if the second appearance parameter is assigned to at least one point of the candidate trajectory.

[0140] A third trajectory appearance parameter can be assigned to the candidate trajectory if gyration of the candidate trajectory is impossible given the length of the haul rope 14, or if gyration is impossible given the speed of the surface building 10, which corresponds to a gyration radius that is too small.

[0141] Figure 4 shows, for example, a classification of trajectories according to three levels of appearance. For example, with regard to trajectories 25, 26 and 27, it can be seen that corrective action must be taken if the surface vessel enters one of these trajectories to avoid damaging the underwater device 11.

[0142] He can also observe that trajectory 30 is impossible.

[0143] With regard to other trajectories, for example trajectory 24, the surface vessel 10 can engage in it without fear of damaging the underwater device 11.

[0144] Steps 100, 200, 300 and 400 of the process can be implemented dynamically or periodically, so as to regularly refresh the guidance aid, taking into account the change in position of the surface building 10, as well as the possible change in current depth of the underwater device 11.

[0145] According to another advantageous embodiment, the positioning of the surface building 10 on one of the points of the candidate trajectory can be processed by computer simulation, in order to anticipate the possible actions to be implemented.

[0146] In relation to the example in [Fig.4], such a simulation can for example make it possible to identify whether the candidate trajectory 24 retains the first trajectory appearance parameter, or whether another trajectory appearance parameter is assigned to it, after the last point of the current candidate trajectory 24.

[0147] The simulation of the positioning of the surface building 10 on one of the points of the candidate trajectory can be carried out, for example, in response to a "click / drag" movement of the point representing the surface building 10 on one of the points of the candidate trajectory, on the graphical interface, or more generally in response to a pointing action on the graphical interface adapted to the selection of one of the points.

[0148] The positioning on future points of a candidate trajectory, as well as the candidate trajectories and / or corresponding actions, can be displayed in a sub-part of the human-machine interface, for example in the form of a thumbnail.

[0149] Figure 6 illustrates the guidance assistance system 500 according to embodiments of the invention.

[0150] The guidance system 500 may include a human-machine interface 501, in the form of a console, and a pointing device configured to allow pointing on the graphical interface. The human-machine interface (HMI) 501 is configured to generate a display of an enhanced map and to receive user (operator) data such as vertical margins, the radius used in dual bathymetry, and / or candidate trajectories. The guidance system 500 is configured to generate a display of the zones and candidate trajectories according to their ranking and / or to transmit instructions relating to these actions.

[0151] The guidance assistance system 500 includes a computing device 502 connected to the human-machine interface 501.

[0152] The computing device 502 comprises a discretization unit 5021 configured to discretize the geographic sector around the surface building into a plurality of zones, a first computing unit 5022 configured to compute the set of candidate trajectories of the surface building in the geographic sector, and a classification unit 5023 configured to classify each candidate trajectory according to the degree of accessibility of the area of ​​the geographical sector crossed by the possible trajectory, and according to the feasibility of one or more predefined actions on said candidate trajectory.

[0153] The computing device 502 can receive or determine surface vessel navigation parameters, and / or winch parameters representing the length of the cable 14 unspooled. Such parameters can be extracted by a immersion assistance service server 503.

[0154] When it is detected that actions need to be taken to avoid damage to the underwater device 11, the computing device 502 can transmit corresponding commands to the server of the immersion assistance service 503.

[0155] The immersion assistance service server 503 can be connected either to a simulator 504 in a simulation use of the guidance assistance device 500, or to a navigation parameter determination unit 505 onboard in the surface building 10 to determine the navigation parameters.

[0156] The computing device 502 can also be connected to a map server 506 which provides bathymetry data.

Claims

Demands

1. A method for assisting the guidance of a surface vessel (10) intended to tow a submersible device (11) by means of a tow cable (14), the method comprising: a) a discretization of the geographical sector (21) around the surface building (10) into a plurality of zones (22, 23), each zone (22, 23) being classified according to a degree of accessibility among a set of degrees of accessibility, according to the bathymetry of the geographical sector and current navigation parameters of the surface building (10) including the length of the haul rope (14) (100); b) a calculation of a set of candidate trajectories (24, 25, 26) of the surface vessel (10) in said geographical sector (21), each candidate trajectory (24, 25, 26) corresponding to a different rate of rotation from the current position of the surface vessel (10) (200); (c) a ranking of each candidate trajectory (24, 25, 26) according to the degree of accessibility of the area of ​​the geographical sector crossed by the possible trajectory (24, 25, 26), and according to the feasibility of one or more predefined actions on said candidate trajectory (24, 25, 26) (300); d) a generation of a display of the zones (22, 23) and candidate trajectories (24, 25, 26) on a human-machine interface, according to their classification and / or a transmission of instructions relating to said actions (400).

2. A method according to claim 1, wherein each zone has a margined minimum depth, said margined minimum depth of each zone being calculated from the minimum depth of all zones located within a predefined radius around said zone, and the underwater device has a current depth and wherein the set of degrees of accessibility comprises: - a first degree of accessibility if the minimum margined depth of the area is greater than or equal to the sum between a vertical protection margin of the underwater device and the current depth of the underwater device, said current depth of the underwater device being calculated as a function of the length of the haul rope and the speed of the surface vessel; - a second level of accessibility if the minimum depth is not exceeded of the zone is strictly less than said sum between the vertical protection margin of the underwater device and the current depth of the underwater device, and if the minimum margined depth of the zone is greater than or equal to the protection margin of the underwater device; - a third degree of accessibility if the minimum margined depth of the zone is strictly less than the vertical protection margin of the underwater device.

3. A method according to claim 2, wherein a first zone appearance parameter, a second zone appearance parameter and a third zone appearance parameter are respectively assigned to the first level of accessibility, the second level of accessibility and the third level of accessibility.

4. A method according to claim 3, wherein the first zone appearance parameter, the second zone appearance parameter and the third zone appearance parameter correspond to different colors.

5. 5. A method according to any one of claims 2 to 4, wherein each candidate trajectory (24, 25, 26) is sampled at a plurality of equidistant points (27), and wherein, at each point (27), from the first point of the candidate trajectory, is assigned: - a first trajectory appearance parameter if said first trajectory appearance parameter was assigned at the previous point and if the estimated depth of the underwater device is less than the sum of the minimum depth margin of the area and the vertical protection margin of the underwater device, the estimated depth of the underwater device (11) being calculated as a function of the length of the haul rope (14), the speed of the surface vessel (10) and the rate of turn corresponding to the candidate trajectory (24, 25, 26) on which the point is located;- a second trajectory appearance parameter if the corrected estimated depth of the underwater device is less than the sum of the minimum margined depth and the vertical protection margin of the underwater device, the corrected estimated depth of the underwater device (11) being calculated as a function of the length of the haul rope (14), the speed of the surface vessel (10), the rate of turn corresponding to the candidate trajectory (24, 25, 26) on which the point is located, and one or more predefined actions on said; candidate trajectory, the second trajectory appearance parameter being further also assigned to the following points of the candidate trajectory (24, 25, 26); - a third trajectory appearance parameter if gyration of the candidate trajectory (24, 25, 26) is impossible given the length of the haul rope (14), or if gyration is impossible given the speed of the surface building (10), the third trajectory appearance parameter being further also assigned to the following points of the candidate trajectory.

6. 6. A method according to claim 5, wherein the first trajectory appearance parameter, the second trajectory appearance parameter and the third trajectory appearance parameter correspond to different colors.

7. 7. A method according to any one of claims 2 to 6, further comprising a step of correcting the vertical protection margin of the underwater device (11), and / or a step of correcting the predefined radius used in the calculation of the minimum margined depth.

8. 8. A method according to any one of the preceding claims, wherein said predefined actions include an action of raising the underwater device (11) and / or an action of accelerating the surface vessel (10).

9. 9. A method according to any one of the preceding claims, wherein the feasibility of one or more predefined actions on said candidate trajectory (24, 25, 26) is calculated taking into account the time to carry out the action before the arrival of the surface building (10) in an area (22, 23) classified according to a degree of accessibility different from the area corresponding to the current position of the surface building (10).

10. 10. A method according to any one of the preceding claims, wherein the step of generating a display of each possible trajectory (24, 25) comprises generating a display of the trajectory in the form of an arc of a circle passing through a point representing the surface vessel (10), or in the form of a segment (26) aligned with the point representing the heading of the surface vessel (10).

11. 11. A method according to any one of the preceding claims, wherein steps a) to d) are repeated periodically.

12. 12. A method according to any one of the preceding claims, comprising, in response to the user's selection of one of the points (27) located on the representation of one of the candidate trajectories (24, 25, 26) generated on the human machine interface, a simulation step of steps a) to d), considering that the surface building (10) is fictitiously positioned at the level of said point (27).

13. 13. Product computer program, comprising instructions for carrying out the process according to any one of claims 1 to 12 when the program is executed by a processor.

14. 14. A guidance aid system for a surface vessel intended to tow a subsea device by means of a tow cable, the system comprising: - A computing device (502) comprising: — a discretization unit (5021), configured to discretize the geographic sector around the surface vessel into a plurality of zones, each zone being classified according to a degree of accessibility from among a set of degrees of accessibility, according to current navigation parameters of the surface vessel including the length of the tow cable; — a first computing unit (5022), configured to calculate a set of candidate trajectories of the surface vessel in said geographic sector, each candidate trajectory corresponding to a different rate of turn from the current position of the surface vessel;— a classification unit (5023), configured to classify each candidate trajectory according to the degree of accessibility of the area of ​​the geographical sector crossed by the possible trajectory (24, 25, 26), and according to the feasibility of one or more predefined actions on said candidate trajectory (24, 25, 26); - A human-machine interface (501) configured to generate a display of the areas and candidate trajectories according to their classification and / or to transmit instructions relating to said actions.

15. 15. System according to claim 14, wherein the underwater device comprises a sonar.

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