Electronic device and method for generating an obstacle database for an aircraft, computer program and associated computer support

Abstract

Electronic device and method for generating an obstacle database for an aircraft, computer program and associated computer support. The invention relates to an electronic device for generating an obstacle database for an aircraft, comprising: - a module for acquiring an initial obstacle database, the initial obstacle database comprising elevation and position data for several obstacles (70); - a module for creating at least one global obstacle volume (GOV) encompassing at least partially a plurality of obstacles (70) and comprising an envelope (72) with an upper surface (74) of an area greater than a predefined minimum area, the upper surface (74) having an elevation (ELV) of constant value and being, at at least one point, distant from the ground (76) by at least a predefined minimum height;and - a module for generating a modified obstacle database from the initial acquired obstacle database, the modified obstacle database including at least one global obstacle volume (GOV) created. Figure for the abbreviation: Figure 5;

Description

Title of the invention: Electronic device and method for generating an obstacle database for an aircraft, associated computer program and computer support

[0001] The present invention relates to an electronic device for generating an obstacle database for an aircraft, the obstacle database being configured to be used by an avionics system.

[0002] The invention also relates to a method of generating an obstacle database for an aircraft, the obstacle database being configured to be used by an avionics system, the method being implemented by such an electronic generation device.

[0003] The invention also relates to a computer program comprising software instructions which, when executed by a computer, implement such a generation process.

[0004] The invention also relates to a computer-readable computer medium, comprising an obstacle database for an aircraft, the obstacle database having been generated via such a generation process.

[0005] The invention relates to the field of aircraft obstacle databases used by avionics systems, in particular by systems for preventing and warning aircraft of collision risks with obstacles. Each obstacle database is then, for example, included in the avionics system, such as the prevention and warning system; or stored on a computer medium connected to the avionics system, such as the prevention and warning system.

[0006] Terrain Awareness and Warning System (TAWS) and Terrain Awareness and Warning System (HTAWS) are known for aircraft.

[0007] These avionics systems are mandatory for airliners, transport aircraft, and regional aircraft, and are becoming mandatory for helicopters as well. They are based on the presence, on board the aircraft, of a terrain database covering the aircraft's operating area. This database contains the ground altitude relative to sea level, also called MSL (Medium Sea Level), at regular intervals that define the scale, generally expressed in arcseconds (SA). A database can contain several scales depending on the geography; for example, for airplanes, areas around airports are better resolved, for example, 3 SA, and for the rest of the land, less resolved, for example, 15 SA. For a dedicated system For helicopters that can potentially land anywhere, a higher resolution 3 SA database is typically preferred over the aircraft's entire operating area, which is generally restricted for a helicopter.

[0008] The terrain database can be supplemented by an obstacle database, the obstacle database comprising point obstacle data providing a radius and a height above ground for each obstacle in the database, and optionally linear obstacle data, for example, the high-voltage power line network of a country's electrical system with a height above ground for each pylon on a line. This obstacle data is particularly useful for helicopters flying close to the ground.

[0009] TAWS or HTAWS systems then use terrain and obstacle databases; the position provided by an aircraft positioning system; as well as flight parameters, such as heading, speed and vertical speed, provided by aircraft sensors; in order to determine a risk of collision with the ground or a more or less close obstacle and trigger different levels of alert depending on the imminence of this risk of collision.

[0010] TAWS or HTAWS systems are also equipped with a display device to allow pilots to be aware of the risks of collision with the ground or obstacles. Usually, the display is two-dimensional with a color code from green to red to illustrate the proximity of the ground around the aircraft, and obstacle symbols also colored from green to red according to their relative altitudes with respect to the aircraft.

[0011] The most recent warning and prevention systems also have a three-dimensional representation allowing the display, in a synthetic vision system (SVS), of the risks of collision with the ground or obstacles, whether point or linear.

[0012] These systems are standardized and regulated, in particular by the DO-367 standard, entitled "Minimum Operational Performance Standards (MOPS) for Terrain Awareness and Warning Systems (TAWS) Airbome Equipment".

[0013] However, these obstacle databases are not suitable for flights in dense urban environments where the very high number of obstacles poses problems of computing and display performance on onboard equipment with limited resources.

[0014] The aim of the invention is then to propose an electronic device, and an associated method, for generating an obstacle database that is more suitable for flights in dense urban environments.

[0015] To this end, the invention relates to an electronic device for generating an obstacle database for an aircraft, the obstacle database being configured for use by an avionics system, the device comprising:

[0016] - an acquisition module configured to acquire an initial database obstacles, the initial obstacles database containing elevation and position data for several obstacles;

[0017] - a creation module configured to create at least one overall obstacle volume, each overall obstacle volume encompassing at least partially a plurality of obstacles and comprising an envelope with a top surface area greater than a predefined minimum area, the top surface having a constant elevation and being, at at least one point, at least a predefined minimum height above the ground; and

[0018] - a generation module configured to generate a modified database obstacles from the initial acquired obstacle database, the modified obstacle database including at least one overall volume of obstacles created.

[0019] Thus, the generation device according to the invention makes it possible to generate an obstacle database simplifying the calculation performed by an obstacle protection function for the generation of an alert, this calculation then being carried out with respect to the overall volume of obstacle, rather than with respect to the plurality of unitary obstacles encompassed by said overall volume of obstacle; or again simplifying the display of one or more views of the external environment presented in the cockpit, by then displaying only the overall volume of obstacle, rather than said plurality of unitary obstacles.

[0020] According to other advantageous aspects of the invention, the electronic generation device comprises one or more of the following features, taken individually or in all technically possible combinations:

[0021] - the creation module is configured to determine at least one area of obstacle grouping, each grouping zone having an obstacle density greater than a predefined minimum density and being associated with a respective overall obstacle volume, and for each grouping zone, a number of fully enclosed obstacles divided by the total number of obstacles at least partially enclosed by said overall obstacle volume is greater than a predefined minimum ratio;

[0022] the minimum predefined ratio being preferably greater than or equal to 0.8; preferably even greater than or equal to 0.9;

[0023] - The creation module is configured to determine each grouping zone via a data partitioning algorithm, each grouping area being polygonal in shape;

[0024] the partitioning algorithm being preferably a spatial grouping algorithm, more preferably a density-based spatial grouping algorithm, such as a density-based spatial grouping algorithm for noisy applications;

[0025] - The creation module is configured to determine each grouping zone from a mesh of an area covered by the initial obstacle database, by calculating for each mesh an obstacle density and a characteristic elevation of obstacles, then grouping related meshes having a characteristic elevation belonging to the same predefined range of elevation values ​​and each having a density greater than a predefined minimum density;

[0026] the characteristic elevation being preferably equal to an average or maximum elevation of a predefined proportion of the obstacles included in said mesh;

[0027] the predefined proportion preferably being substantially equal to 80% of the obstacles included in said mesh;

[0028] - for each overall obstacle volume, the constant value of the elevation of the upper surface is equal to the sum of a predefined margin and the maximum value of the elevations of the obstacles fully encompassed by said overall volume;

[0029] - for each overall obstacle volume, the constant value of the elevation of the upper surface is equal to a predefined value;

[0030] - the elevation is of a type chosen from an altitude of the upper surface and a height of the upper surface relative to the ground;

[0031] - the predefined minimum area is greater than or equal to 10 ha;

[0032] - the predefined minimum height is greater than or equal to 30 meters;

[0033] - the creation module is configured to create each global obstacle volume in outside of landing zone(s), vertiport(s) and clearance zone(s);

[0034] each clearance zone(s) preferably being chosen from the group consisting of: a park, and a stadium; and

[0035] - the generation module is configured during the generation of the modified database obstacle data, to remove each obstacle fully encompassed by a respective global obstacle volume.

[0036] The invention also relates to a method for generating an obstacle database for an aircraft, the obstacle database being configured for use by an avionics system, the method being implemented by an electronic generation device and comprising the following steps:

[0037] - acquire an initial obstacle database, the initial obstacle database including elevation and position data for several obstacles;

[0038] - create at least one overall obstacle volume, each overall obstacle volume encompassing at least partially a plurality of obstacles and comprising an envelope with an upper surface area greater than a predefined minimum area, the upper surface having a constant elevation and being, at at least one point, at least a predefined minimum height above the ground; and

[0039] - generate a modified obstacle database from the initial database of obstacle data acquired, the modified obstacle database including at least one overall volume of obstacle created.

[0040] The invention also relates to a computer program comprising software instructions which, when executed by a computer, implement a generation process, as defined above.

[0041] The invention also relates to a computer-readable computer medium, comprising an obstacle database for an aircraft, the obstacle database having been generated via a generation process, as defined above.

[0042] These features and advantages of the invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings, in which:

[0043] [Fig-1] [Fig.1] is a schematic view of a civil aircraft according to the invention, comprising a propulsion system and an avionics installation including an electronic information display system, an electronic system for preventing a risk of collision to the aircraft, a terrain database and an obstacle database; the obstacle database having been generated by an electronic generation device and including at least one overall obstacle volume encompassing at least partially a plurality of obstacles;

[0044] [Fig.2] [Fig.2] is a schematic view of a dense urban area with several overall obstacle volumes;

[0045] [Fig.3] [Fig.3] is a schematic representation illustrating the grouping of obstacles by grouping zones for the creation of global obstacle volumes, according to a first example of embodiment;

[0046] [Fig.4] [Fig.4] is a representation analogous to that of [Fig.3], according to a second embodiment;

[0047] [Fig. 5] [Fig. 5] is a schematic representation illustrating a first mode M1 where the elevation of an upper surface of a global obstacle volume, whose value is constant, is the altitude of the upper surface, and respectively a second mode M2 ​​where the elevation of the upper surface of a global obstacle volume, whose value is constant, is the height of the upper surface relative to the ground; and

[0048] [Fig.6] [Fig.6] is a flowchart of a method, according to the invention, for generating an obstacle database for the aircraft, the method being implemented by the generation device of [Fig.1].

[0049] In the following description, the expression "approximately equal to" defines a relationship of equality to plus or minus 20%, preferably to plus or minus 10%, and preferably still to plus or minus 5%.

[0050] In [Fig.1], a civil aircraft 10 comprises a propulsion system 12 and an avionics installation 15 for pilot assistance, the avionics installation 15 being intended to be carried on board the aircraft 10.

[0051] The civil aircraft 10 is in particular a rotary-wing aircraft, such as a civil helicopter, as shown in [Fig. 1]. Alternatively, the civil aircraft 10 is an airliner, an urban air mobility vehicle, also called a UAM (Urban Air Mobility) vehicle, or a civil drone remotely piloted by a remote operator.

[0052] The propulsion system 12 comprises at least one engine 16 and at least one energy storage unit 17. The propulsion system 12 is, for example, a combustion propulsion system, and the engine or engines 16 are then combustion engines, and the energy storage unit 17 is a fuel tank. Alternatively, the propulsion system 12 is an electric propulsion system, and the engine or engines 16 are then electric motors, and the energy storage unit 17 comprises an electric battery and / or a fuel cell. Alternatively still, the propulsion system 12 is a hybrid propulsion system comprising several engines 16, namely at least one combustion engine and at least one electric motor. The at least one energy storage unit 17 then comprises at least one fuel tank and at least one electric battery and / or a fuel cell.

[0053] The flight assistance installation 15 includes an electronic information display system 18, a human-machine interface 19 and an electronic system 20 for preventing a risk of collision for the aircraft 10, the prevention system 20 being connected to the information display system 18.

[0054] In the example of [Fig.1], the piloting aid installation 15 also includes a first database 22, also called the terrain database, and a second database 24, also called the obstacle database, the second database 24 being then distinct from the first database 22. The obstacle database is generated by an electronic generation device 25, also shown in [Fig.1].

[0055] Alternatively, not shown, the terrain database and the obstacle database are combined into a single database, and the piloting assistance system 15 then includes said database. According to this alternative, the portion of the database corresponding to obstacle data is also generated by the electronic generation device 25.

[0056] The information display system 18 typically includes an information display screen 28.

[0057] The human-machine interface 19 is for example integrated into the screen 28 of the information display system 18 in the form of a touch screen.

[0058] According to another example, the human-machine interface 19 is a real, i.e. physical keyboard, or a virtual keyboard, or even an actionable cursor connected to the information display system 18.

[0059] The human-machine interface 19 is capable of allowing the operator to select elements or enter data.

[0060] The prevention system 20 includes a module 30 for receiving a position of the aircraft 10, a module 32 for obtaining at least one obstacle volume and a module 34 for controlling at least one action among the display of at least one obstacle volume and the generation of an alert in case of risk of penetration of the aircraft 10 into a respective obstacle volume.

[0061] In the example of [Fig.1], the electronic prevention system 20 includes a first information processing unit 40 formed for example of a first memory 42 and a first processor 44 associated with the first memory 42.

[0062] In the example of [Fig. 1], the receiving module 30, the obtaining module 32, and the control module 34 are each implemented as a software program, or a software component, executable by the first processor 44. The first memory 42 of the electronic prevention system 20 is then capable of storing a receiving program, a obtaining program, and a control program. The first processor 44 is then capable of executing each of the following programs: the receiving program, the obtaining program, and the control program.

[0063] In an alternative not shown, the receiving module 30, the obtaining module 32 and the control module 34 are each made in the form of a programmable logic component, such as an FPGA (Field Programmable Gate Array) or in the form of a dedicated integrated circuit, such as an ASIC (Application Specified Integrated Circuit).

[0064] When the electronic prevention system 20 is implemented in the form of one or more software programs, i.e., in the form of a computer program, it is also capable of being stored on a computer-readable medium (not shown). A computer-readable medium is, for example, a medium capable of storing electronic instructions and being connected to a bus of a computer system. For example, a readable medium is an optical disc, a magneto-optical disc, a ROM, a RAM, any type of non-volatile memory (e.g., EPROM, EEPROM, FLASH, NVRAM), a magnetic card, or an optical card. A computer program comprising software instructions is then stored on the readable medium.

[0065] The electronic generation device 25 comprises a module 50 for acquiring an initial obstacle database, a module 52 for creating at least one global obstacle volume VGO and a module 54 for generating a modified obstacle database.

[0066] In the example of [Fig.1], the generation electronic device 25 includes a second information processing unit 60 formed for example of a second memory 62 and a second processor 64 associated with the second memory 62.

[0067] In the example of [Fig. 1], the acquisition module 50, the creation module 52, and the generation module 54 are each implemented as a software program, or a software component, executable by the second processor 64. The second memory 62 of the electronic generation device 25 is then capable of storing acquisition software, creation software, and generation software. The second processor 64 is then capable of executing each of the following software programs: acquisition software, creation software, and generation software.

[0068] In an alternative not shown, the acquisition module 50, the creation module 52 and the generation module 54 are each made in the form of a programmable logic component, such as an FPGA (Field Programmable Gate Array), or in the form of a dedicated integrated circuit, such as an ASIC (Application Specified Integrated Circuit).

[0069] When the 25th generation electronic device is implemented in the form of one or more software programs, i.e., in the form of a computer program, it is also capable of being stored on a computer-readable medium (not shown). The computer-readable medium is, for example, a medium capable of storing electronic instructions and being connected to a bus of a computer system. For example, the readable medium is an optical disc, a magneto-optical disc, a ROM, a RAM, any type of non-volatile memory (e.g., EPROM, EEPROM, FLASH, NVRAM), a magnetic card, or an optical card. A computer program comprising software instructions is then stored on the readable medium.

[0070] The receiving module 30 is configured to receive the position of the aircraft 10, and is known in itself. The receiving module 30 is, for example, configured to receive said position from a positioning system of the aircraft 10, such as a satellite positioning system, also called a GNSS (Global Navigation Satellite System).

[0071] The acquisition module 32 is configured to obtain, from the obstacle database 24 and according to the position of the aircraft 10, at least one obstacle volume.

[0072] According to the invention, at least one obstacle volume is a global obstacle volume VGO encompassing at least partially a plurality of obstacles 70, as illustrated in Figures 2 and 4.

[0073] Each overall obstacle volume VGO comprises an envelope 72 with an upper surface 74 of area A greater than a predefined minimum area Amin, the upper surface 74 having an elevation ELV of constant value and being, at at least one point, distant from the ground by at least a predefined minimum height Hmin.

[0074] The predefined minimum area Amin is typically greater than or equal to 10 ha, i.e. greater than or equal to 100,000 m2. The predefined minimum height Hmin is for example greater than or equal to 30 meters.

[0075] Each overall obstacle volume VGO vertically encompasses at least partially the plurality of obstacles 70. In other words, each overall obstacle volume encompasses at least partially, along a vertical direction, the plurality of obstacles 70. Said obstacles 70 are fully encompassed horizontally within the corresponding overall obstacle volume VGO. In other words, said obstacles 70 are, along a horizontal plane perpendicular to the vertical direction, fully encompassed within the overall obstacle volume VGO.

[0076] A person skilled in the art will understand that all the obstacles 70 of the plurality of obstacles 70 associated with a global obstacle volume VGO are horizontally, that is, along the horizontal plane, completely enclosed by said global obstacle volume VGO; and vertically, that is, along the vertical direction, at least partially enclosed by said global obstacle volume VGO, some obstacles 70 being completely enclosed, both horizontally and vertically, by the global obstacle volume VGO, and potentially other obstacles 70 being enclosed horizontally, but only partially along the vertical direction, by said global obstacle volume VGO. An obstacle completely enclosed vertically is an obstacle 70 having an elevation less than that of the upper surface 74 of the corresponding global obstacle volume VGO.

[0077] In the example of [Fig.2], several global obstacle volumes VGO are represented, with a constant elevation value ELV varying from one global obstacle volume VGO to another.

[0078] The ELV elevation is typically an altitude ALT of the upper surface 74 or a height H relative to the ground 76 of the upper surface 74.

[0079] According to a first mode Ml, visible in [Fig.5], the elevation ELV of the upper surface 74, whose value is constant, is the altitude ALT of the upper surface 74. In other words, according to this first mode Ml, each global obstacle volume VGO has its upper surface 74 exhibiting a constant value of altitude ALT.

[0080] According to a second mode M2, also visible in [Fig.5], the elevation ELV of the upper surface 74, whose value is constant, is the height H of the upper surface 74 relative to the ground 76. In other words, according to this second mode M2, each global obstacle volume VGO has its upper surface 74 exhibiting a constant value of height H relative to the ground 76.

[0081] The person skilled in the art will observe that the first mode M1 is equivalent to the second mode M2 ​​when the ground 76 has a constant altitude over the whole of a respective global obstacle volume VGO, as in the example of [Fig.2]; and as a corollary that the first mode M1 results in a top surface 74 different from that obtained according to the second mode M2 ​​only when the altitude of the ground 76 varies within the respective global obstacle volume VGO.

[0082] The mode between the first mode M1 and the second mode M2 ​​is likely to vary from one overall obstacle volume VGO to another. In other words, when several overall obstacle volumes VGO are obtained by the acquisition module 32, the constant-value ELV elevation is, for example, variable from one overall obstacle volume VGO to another.

[0083] Alternatively, the mode between the first mode M1 and the second mode M2 ​​is identical from one overall obstacle volume VGO to another. In other words, according to this alternative, when several overall obstacle volumes VGO are obtained by the acquisition module 32, the constant-value elevation ELV is of the same type for all overall obstacle volumes VGO.

[0084] Advantageously, if a respective obstacle 70 among the plurality of obstacles 70 is only partially encompassed by a corresponding global obstacle volume VGO and has an elevation of greater value than that of the upper surface 74 of said global obstacle volume VGO, then said obstacle is represented as protruding from the envelope 72 of said global obstacle volume VGO, the apex 78 of this obstacle protruding from the upper surface 74 of said global obstacle volume VGO, as shown in the views S VS and VD in [Fig.3], or in the example of [Fig.4].

[0085] Advantageously, the constant value of the ELV elevation of the upper surface 74 of the corresponding overall obstacle volume VGO is determined such that the number of obstacles 70 protruding from the upper surface 74 divided by the total number of obstacles 70 at least partially enclosed by the corresponding overall obstacle volume VGO is less than a predefined maximum ratio Rmax. In other words, according to this advantageous aspect, the constant value of the ELV elevation of the upper surface 74 of the corresponding overall obstacle volume VGO is determined such that the number of obstacles 70 that are only partially enclosed by the corresponding overall obstacle volume VGO represents, relative to the total number of obstacles 70 enclosed by the overall obstacle volume VGO, whether partially or entirely, a proportion, or even a percentage lower than this predefined maximum ratio Rmax.

[0086] The predefined maximum ratio Rmax is preferably less than or equal to 0.2, i.e., 20%; preferably even less than or equal to 0.1, i.e., 10%. In other words, when the predefined maximum Rmax is less than or equal to 0.2, at most 20% of the obstacles 70 are only partially encompassed by a respective overall obstacle volume VGO, the remaining 80% being fully encompassed by said overall obstacle volume VGO. Similarly, when the predefined maximum Rmax is less than or equal to 0.1, at most 10% of the obstacles 70 are only partially encompassed by a respective overall obstacle volume VGO, the remaining 90% being fully encompassed by said overall obstacle volume VGO.

[0087] The control module 34 is configured to control at least one action among the display, on the display screen 28, of at least one obstacle volume, and the generation of an alert in case of risk of penetration of the aircraft 10 into a respective obstacle volume.

[0088] Advantageously, the envelope 72 of the overall obstacle volume VGO has a transparency greater than 20% when the overall obstacle volume VGO is displayed on the display screen 28. This display of the envelope 72 of the overall obstacle volume VGO with a transparency greater than 20% then allows the operator of the aircraft 10, such as the pilot, to visualize both the overall obstacle volume VGO and, through transparency, cultural data (rivers, roads, railways, ...) located under the overall obstacle volumes VGO.

[0089] Alternatively, an opaque display, i.e. with a transparency lower than the predefined minimum value, can be used to improve graphics performance.

[0090] Only obstacles 70 whose top 78 exceeds the upper surface 74 of the corresponding overall obstacle volume VGO are displayed as unitary obstacles, typically in the form of a three-dimensional cylinder, with a height and diameter just greater than those of the real obstacle, for example with a height and diameter 10% greater, preferably 5% greater, than those of the real obstacle.

[0091] Advantageously, the envelope 72 of the overall obstacle volume VGO has a color that varies according to the difference in altitude between an altitude of the aircraft 10 and an altitude ALT of the upper surface 74 of said envelope 72. For example, a volume below the aircraft 10 and not representing any risk of incursion in the short term is displayed in green, a volume close to the altitude of the aircraft 10 is shown in khaki; and a volume higher than the altitude of the aircraft 10 is shown in brown.

[0092] Alternatively, this variable color display is based on five altitude ranges and colors: below - 1000 ft (from the English feet, or pieds in French) in dark green; - 1000 ft to - 500 ft in green; - 500 ft to 500 ft in khaki; 500 ft to 1500 ft in dark brown; and above 1500 ft in light brown.

[0093] For the generation of an alert, any intrusion or threat of intrusion into obstacle volumes, in particular into a corresponding global obstacle volume VGO, and outside specific areas (vertiports, clearances, etc.), is the subject of a specific visual and / or audible indication, prompting the pilot to gain altitude to exit the obstacle volume or to switch to flight rules based on visual detection of terrain and obstacles if external visibility permits.

[0094] The generation of the obstacle database 24 for the aircraft 10 by the electronic generation device 25 will now be described, the obstacle database 24 being configured for use by an avionics system, such as the electronic prevention system 20.

[0095] The acquisition module 50 is configured to acquire an initial obstacle database, the initial obstacle database comprising elevation and position data for several obstacles 70. A person skilled in the art will understand that the initial obstacle database is typically an initial version of the obstacle database 24.

[0096] The creation module 52 is configured to create at least one global obstacle volume VGO.

[0097] The creation module 52 is, for example, configured to determine at least one obstacle grouping zone 70, each grouping zone having an obstacle density 70 greater than a predefined minimum density and being associated with a respective overall obstacle volume VGO, and for each grouping zone, the number of fully enclosed obstacles 70 divided by the total number of obstacles 70 at least partially enclosed by said overall obstacle volume VGO is greater than a predefined minimum ratio Rmin. The predefined minimum ratio Rmin is preferably greater than or equal to 0.8; preferably even greater than or equal to 0.9.

[0098] In the horizontal plane, two embodiment examples are presented below to define the limits of the global obstacle volumes VGO.

[0099] According to a first embodiment, illustrated in [Fig.3], the creation module 52 is configured to determine each grouping area via a data partitioning algorithm, each grouping area being polygonal in shape.

[0100] The partitioning algorithm is typically chosen from spatial clustering algorithms, also called spatial clustering methods or spatial partitioning methods, in particular density-based spatial clustering. such as the DBSCAN algorithm or method (from the English Density-Based Spatial Clustering of Applications with Noise), or spatial clustering algorithm based on the density of applications with noise.

[0101] This first example of an implementation relies, for example, on a delimitation of 150 urban areas, as provided by open data services such as Copemicus, which, using satellite data, provide a digital map of soil types, for example, and among other things, fields, forests, deserts, or urban areas. These urban areas can be defined with a high degree of granularity, potentially involving processing that is too complex for an onboard avionics system.

[0102] Optionally, a first phase consists of generating simpler polygons, i.e., with fewer segments, to delimit urban areas, as shown in [Fig. 3] with a simplification polygon 155 resulting from the initial delimitation 150. This first phase is carried out, for example, by implementing the Doulas-Peucker algorithm. The urban areas thus defined can cover vast geographical areas with highly variable obstacle heights and densities within an urban area, for example, in the territory of large metropolitan areas.

[0103] Also, a second phase, also optional, consists of dividing the polygons 155 from the first step into several polygons 160, also called sub-polygons, characterized by more homogeneous heights and obstacle densities, typically using the aforementioned partitioning algorithm.

[0104] During a third phase, among the different polygons 160 obtained for an urban area, only those comprising an obstacle density greater than a predefined threshold become the respective basis 165 of a corresponding global obstacle volume VGO.

[0105] Other polygons, that is, polygons other than those serving as the basis for a respective global obstacle volume VGO, are not retained; and the obstacles included in these other polygons are then retained in the obstacle database 24. For example, a suburban neighborhood without any obstacles listed in the obstacle database 24 of a larger urban area will not be part of a global obstacle volume VGO, while the city center of that same urban area with a high density of obstacles will be covered by a respective global obstacle volume VGO.

[0106] According to a second embodiment, illustrated in [Fig. 4], the creation module 52 is configured to determine each grouping zone from a mesh 170 of an extent covered by the initial obstacle database, the mesh 170 comprising a plurality of cells 172; by calculating for each cell 172 an obstacle density 70 and a characteristic obstacle elevation 70; then in grouping connected cells having a characteristic elevation belonging to the same predefined range of elevation values ​​and each exhibiting a density greater than a predefined minimum density.

[0107] The characteristic elevation is, for example, an average or maximum elevation of a predefined proportion of the obstacles 70 included in said mesh. The predefined proportion is advantageously substantially equal to 80% of the obstacles 70 included in said mesh.

[0108] For this second embodiment, the 170 grid, square or rectangular, covers the entire geographical area of ​​the obstacle database 24, regardless of the soil type, whether urban or not. This 170 grid is typically defined in meters or degrees, for example, a grid of squares with sides of 2000 meters or a rectangular grid with 0.01 degrees of latitude and longitude. Each cell 172 is then typically in the shape of a square with sides of 2 km or a rectangle with 0.01 degrees of latitude and longitude.

[0109] The next step consists of calculating the obstacle density and a characteristic of obstacle height, for example, the average or maximum height of the lowest 80% of obstacles, for each of the grid cells 172 of the geographical area being studied. Then, for grid cells 172 with an obstacle density exceeding a certain threshold, the grid cells connected by similar characteristics in terms of obstacle heights 70 are grouped based on a few height thresholds, as shown with the groupings 175 in [Fig. 4]. In [Fig. 4], a first grouping 175A corresponds to a first range of obstacle height values ​​70; a second grouping 175B corresponds to a second range of obstacle height values ​​70, distinct from the first range; and a third grouping 175C corresponds to a third range of obstacle height values ​​70, distinct from the first and second ranges. At the [Fig.[4], the first 175A, second 175B, and third 175C groupings are represented with three different types of filling to distinguish them from one another: the first grouping 175A is filled with closely spaced hatching, the second grouping 175B is unhatched, and the third grouping 175C is filled with hatching that is more widely spaced than the first grouping 175A. These groupings 175 of the initial mesh 170 then form the bases 180 of the global obstacle volumes VGO. In [Fig. 4], a first base 180A of a first global obstacle volume VGO is then associated with the first grouping 175A; a second base 180B of a second global obstacle volume VGO is associated with the second grouping 175B; and a third base 180C of a third overall obstacle volume VGO is associated with the third grouping 175C.

[0110] Advantageously, this second embodiment allows for the creation of global VGO obstacle volumes outside urban areas such as around a wind farm for example.

[0111] In the vertical plane, the limits of the global obstacle volumes VGO are defined for example according to two embodiment examples.

[0112] A first embodiment corresponds to the first mode M1, visible in [Fig. 5], and consists of defining the altitude of a flat surface representing the upper surface 74 of the overall obstacle volume VGO. This altitude is not necessarily above all the obstacles 70; such an approach could in fact lead to an unnecessarily high overall obstacle volume VGO over a large part of the urban area. For example, in Paris, a protection volume covering the Eiffel Tower and the Montparnasse Tower would force the UAMs to operate unnecessarily high for the vast majority of the Parisian urban area. The predefined minimum ratio Rmin, for example 80% or 90%, then represents the quantity of obstacles 70 to be covered by the overall obstacle volume VGO, and therefore advantageously the quantity of obstacles 70 to be removed from the obstacle database 24.The altitude ALT of the upper surface of the protection volume is then, for example, equal to the altitude of the summit of the highest removed obstacle plus a predefined margin. The remaining obstacles, few in number and therefore not penalizing for the calculations of the protection function and the display function, are still treated individually and are represented as outside the global obstacle volumes VGO.

[0113] Still in the vertical plane, a second embodiment corresponds to the second mode M2, shown in [Fig. 5], and consists of defining not the altitude ALT, but the height H above ground level 76 of the overall obstacle volume VGO. The upper surface 74 of the overall obstacle volume VGO is no longer a flat surface, but a surface reproducing the terrain relief offset upwards by the height of the overall obstacle volume VGO, as shown in the second mode M2 ​​in [Fig. 5]. Here again, the definition of the height H of the overall obstacle volume VGO typically takes into account the predefined minimum ratio Rmin of obstacles to be removed from the obstacle database 24, with the tallest remaining obstacles displayed above the overall obstacle volume VGO. The height H of the overall obstacle volume VGO is then equal to the height of the tallest of the removed obstacles plus the predefined margin.

[0114] For each global obstacle volume VGO, the constant value of the elevation ELV of the upper surface 74 is for example equal to the sum of a predefined margin and the maximum value of the elevations of the obstacles 70 fully encompassed by said global volume VGO.

[0115] The predefined margin is, for example, equal to a predefined percentage of the maximum elevation of the obstacles fully enclosed by said overall volume. The predefined percentage is, for example, between 1% and 10%, preferably approximately equal to 5%.

[0116] Alternatively, the predefined margin is a value predefined by an air traffic control authority, for example between 200 ft and 1000 ft, preferably substantially equal to 500 ft.

[0117] In the vertical plane, the first embodiment is advantageous for urban areas built on soil 76 with little relief, but can become penalizing for urban areas on a high relief because it implies an altitude of the upper surface 74 of the overall obstacle volume VGO unnecessarily high for the lower parts of the city.

[0118] In the vertical plane, the second embodiment is advantageous for urban areas on a steep relief, and is less interesting for urban areas with low relief.

[0119] Advantageously, a combination of the two embodiments in the vertical plane can also be implemented. The constant-value ELV elevation is then variable from one overall obstacle volume VGO to another. In other words, for some overall obstacle volumes VGO, the constant-value ELV elevation is the altitude ALT of the upper surface 74 according to the first mode M1; and for other overall obstacle volumes VGO, the constant-value ELV elevation is the height H of the upper surface 74 relative to the ground 76 according to the second mode M2.

[0120] Those skilled in the art will observe that, in the vertical plane, the second embodiment can consist of including the overall obstacle volume VGO directly in the field database 22 by raising each elevation value in database 22 by the height of the overall obstacle volume VGO for the urban area to be protected. The advantage of this technique lies in the absence of specific processing of the overall obstacle volume VGO, no database storage, no calculation of the protection function, and no display of the volume; all processing is carried out in the field.

[0121] As an alternative to these two embodiments in the vertical plane, the altitude ALT or the height H of the overall obstacle volume VGO is not determined based on the predefined minimum ratio Rmin, but directly by a height constant. For example, as an alternative to the first embodiment, the altitude of the upper surface 74 of the overall obstacle volume VGO is set approximately 100 meters above the maximum terrain elevation on the surface of the overall obstacle volume VGO. As an alternative to the second embodiment, the height H of the upper surface 74 of the overall volume of obstacle VGO is fixed, for example substantially equal to 100 meters.

[0122] According to this variant, for each overall obstacle volume VGO, the constant value of the elevation ELV of the upper surface 74 is equal to a predefined value.

[0123] The person skilled in the art will of course understand that the different examples of realization in the vertical plane and in the horizontal plane can be combined in all possible ways to define the overall volume of obstacle VGO in three dimensions.

[0124] Advantageously, the creation module 52 is configured to create each overall obstacle volume (OOV) outside of landing zones, vertiports, and clearance zones. Each clearance zone is typically defined from a clearance zone database specific to each operator, based on the characteristics of the aircraft operated. Each clearance zone is, for example, a park or a stadium.

[0125] According to this advantageous aspect, after the creation of the global obstacle volumes (VGOs) as described above, the creation module 52 is then configured to exclude landing zones, vertiports, and any clearance zones, such as a park or stadium, from these global obstacle volumes (VGOs). These zones are defined, for example, in a specific database; they could be a circle around a vertiport, a number of corridors leading to the vertiport, or any shape defining a clearance zone. These zones are then subtracted from the previously defined global obstacle volumes (VGOs) to obtain their final shapes. Obstacles belonging to these exclusion zones are then stored individually in the obstacle database 24.In some cases, vertiports are installed on the roof of a building and in this case an exclusion zone of the overall obstacle volume VGO will be defined only if the altitude of the vertiport is less than the altitude of the upper surface 74 of the overall obstacle volume VGO.

[0126] The generation module 54 is configured to generate a modified obstacle database from the initial acquired obstacle database, the modified obstacle database including at least one created global obstacle volume (VGO). Those skilled in the art will understand that the modified obstacle database is typically a modified version of obstacle database 24.

[0127] Advantageously, the generation module 54 is configured to, when generating the modified obstacle database, delete each obstacle 70 that is fully encompassed by a respective global obstacle volume VGO.

[0128] The operation of the electronic piloting assistance system 15, and in particular of the generation device 25, will now be explained, notably in with the aid of [Fig.6], representing a flowchart of the method, according to the invention, of generating the obstacle database 24 for aircraft 10.

[0129] During an initial step 200, the generation device 25 acquires, via its acquisition module 50, the initial obstacle database containing elevation and position data for several obstacles 70. The initial obstacle database is typically an initial version of the obstacle database 24.

[0130] At the end of the acquisition step 200, the generation device 25 moves to the next step 210 during which it creates, via its creation module 52, at least one overall obstacle volume VGO.

[0131] According to the invention, at least one obstacle volume created during the creation step 210 is a respective global obstacle volume VGO encompassing at least partially several obstacles 70. The envelope 72 of each global obstacle volume VGO has its upper surface 74 of area A greater than the predefined minimum area Amin, of elevation ELV of constant value and, at at least one point, distant from the ground 76 by at least the predefined minimum height Hmin.

[0132] The creation of the or each global obstacle volume VGO is carried out in the manner described above.

[0133] At the end of the creation step 210, the generation device 25 generates, in a subsequent step 220 and via its generation module 54, the modified obstacle database from the initial obstacle database acquired during the acquisition step 200, the modified obstacle database including at least one global obstacle volume (GOV) created during the creation step 210. The modified obstacle database is then typically a modified version of the obstacle database 24.

[0134] The person skilled in the art will of course understand that the obstacle database 24 configured for use by the avionics system, such as the prevention system 20, is then the modified obstacle database, such as the modified version of the obstacle database 24.

[0135] Thus, the generation device 25 and the generation method according to the invention make it possible to drastically reduce the number of obstacles 70 stored in the obstacle database 24, particularly on the perimeter of dense urban areas, by replacing the numerous obstacles 70 with a small number of global obstacle volumes VGO.

[0136] Another advantage of this reduction in the number of obstacles 70 is a simplification of the calculation of the obstacle monitoring function which, instead of testing a risk of collision with each obstacle 70 in the vicinity of the aircraft 10, tests the risk of collision with a small number of global obstacle volumes VGO.

[0137] Another advantage is a simplification of the obstacle display function 70 on different views presented to the pilot, which, instead of displaying each obstacle 70 in the vicinity of the aircraft 10, displays a small number of overall obstacle volumes VGO. Thus, the risk of exceeding the computing and display capabilities of the avionics system, such as the prevention system 20, is greatly reduced.

[0138] Finally, from a human factors point of view, presenting the pilot with simple global obstacle volumes (GOVs) reduces the cognitive load for the pilot, in particular the difficulties in correctly interpreting the situation and the risk of putting the aircraft 10 in danger following a misinterpretation of the situation.

[0139] It is thus understood that the generation device 25 and the generation method according to the invention are more suitable for flights in the presence of many obstacles 70, in particular in dense urban environments.

Claims

Demands

1. Electronic device (25) for generating an obstacle database (24) for an aircraft, the obstacle database (24) being configured for use by an avionics system (20), the device (25) comprising: - an acquisition module (50) configured to acquire an initial obstacle database, the initial obstacle database comprising elevation and position data for several obstacles (70);characterized in that it further comprises: - a creation module (52) configured to create at least one global obstacle volume (GOV), each global obstacle volume (GOV) encompassing at least partially a plurality of obstacles (70) and having an envelope (72) with an upper surface (74) of area (A) greater than a predefined minimum area (Amin), the upper surface (74) having an elevation (ELV) of constant value and being, at at least one point, at least a predefined minimum height (Hmin) from the ground (76); and - a generation module (54) configured to generate a modified obstacle database from the initial acquired obstacle database, the modified obstacle database including the at least one global obstacle volume (GOV) created.

2. Device (25) according to claim 1, wherein the creation module (52) is configured to determine at least one obstacle grouping zone (70), each grouping zone having an obstacle density (70) greater than a predefined minimum density and being associated with a respective global obstacle volume (GOV), and for each grouping zone, a number of obstacles (70) fully encompassed divided by the total number of obstacles (70) at least partially encompassed by said global obstacle volume (GOV) is greater than a predefined minimum ratio (Rmin), the predefined minimum ratio (Rmin) preferably being greater than or equal to 0.8; preferably even greater than or equal to 0.

9.

3. Device (25) according to claim 2, wherein the creation module (52) is configured to determine each zone of grouping via a data partitioning algorithm, each grouping area being polygonal in shape; the partitioning algorithm preferably being a spatial grouping algorithm, more preferably a density-based spatial grouping algorithm, such as a density-based spatial grouping algorithm for noisy applications.

4. Device (25) according to claim 2, wherein the creation module (52) is configured to determine each grouping zone from a mesh of an extent covered by the initial obstacle database, by calculating for each mesh an obstacle density (70) and a characteristic elevation of the obstacles (70), and then grouping related meshes having a characteristic elevation belonging to the same predefined range of elevation values ​​and each having a density greater than a predefined minimum density; the characteristic elevation preferably being equal to an average or maximum elevation of a predefined proportion of the obstacles (70) included in said mesh; the predefined proportion preferably still being substantially equal to 80% of the obstacles (70) included in said mesh.

5. Device (25) according to any one of claims 2 to 4, wherein, for each global obstacle volume (GOV), the constant value of the elevation (ELV) of the upper surface (74) is equal to the sum of a predefined margin and the maximum value of the elevations of the obstacles (70) fully encompassed by said global volume (GOV).

6. Device (25) according to any one of claims 1 to 4, wherein, for each overall obstacle volume (OOV), the constant value of the elevation (ELV) of the upper surface (74) is equal to a predefined value.

7. Device (25) according to any one of the preceding claims, wherein the elevation (ELV) is of a type selected from an altitude (ALT) of the upper surface (74) and a height (H) relative to the ground (76) of the upper surface (74).

8. Device (25) according to any one of the preceding claims, wherein the predefined minimum area (Amin) is greater than or equal to 10 ha.

9. Device (25) according to any one of the preceding claims, wherein the predefined minimum height (Hmin) is greater than or equal to 30 meters.

10. Device (25) according to any one of the preceding claims, wherein the creation module (52) is configured to create each global obstacle volume (GOV) outside of landing zone(s), vertiport(s) and clearance zone(s); each clearance zone(s) preferably being selected from the group consisting of: a park, and a stadium.

11. Device (25) according to any one of the preceding claims, wherein the generation module (54) is configured, when generating the modified obstacle database, to remove each obstacle (70) fully encompassed by a respective global obstacle volume (GOV).

12. Method of generating an obstacle database (24) for an aircraft (10), the obstacle database (24) being configured for use by an avionics system (20), the method being implemented by an electronic generation device (25) and comprising the following step: - acquiring (200) an initial obstacle database, the initial obstacle database having elevation and position data for several obstacles (70);characterized in that it further comprises the following steps: - creating (210) at least one global obstacle volume (GOV), each global obstacle volume (GOV) encompassing at least partially a plurality of obstacles (70) and having an envelope (72) with an upper surface (74) of area (A) greater than a predefined minimum area (Amin), the upper surface (74) having an elevation (ELV) of constant value and being, at at least one point, at least a predefined minimum height (Hmin) from the ground (76); and - generating (220) a modified obstacle database from the initial acquired obstacle database, the modified obstacle database including the at least one global obstacle volume (GOV) created.

13. A computer program comprising software instructions which, when executed by a computer, implement a method according to claim 12.

14. A computer-readable computer medium, comprising an obstacle database (24) for an aircraft (10), characterized in that the obstacle database (24) was generated via a method according to claim 12.

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