CALCULATION SYSTEM FOR THE MISSION OF AN AIRCRAFT USING AT LEAST AN EXTENDED ISO SHIFT CURVE, AND CORRESPONDING PROCEDURE

Description

[0001] The present invention relates to an aircraft mission calculation system according to the preamble of claim 1.

[0002] The invention applies to aircraft used in civil aviation, in particular in business aviation.

[0003] Such a calculation system is intended in particular to be integrated into a cockpit, in parallel with a flight control system ("Flight Management System" or "FMS" in English), to allow the crew to determine mission trajectories.

[0004] Alternatively, the calculation system is suitable for being integrated into an off-board mission planning system, for example in an airport infrastructure for establishing an aircraft trajectory, in an electronic flight bag ("Electronic Flight Bag" or "EFB"), and / or in a portable electronic device (for example a tablet), or in a PC-type computer.

[0005] The calculation system is adapted to determine a complete trajectory of the aircraft in the horizontal plane and in the vertical plane on several flight levels between a first geographical point of origin and a second geographical point of destination. The mission comprises one or more stages.

[0006] Preparing and defining an aircraft mission between a first geographical point and a second geographical point is a time-consuming task. It requires determining the route the aircraft will follow, the associated flight profile, the passenger, freight and fuel load, and calculating low-speed performance, as well as verifying the aircraft's flight envelope.

[0007] This definition is carried out based on a mission context including meteorology, air routes to be taken, connectivity with satellite communication systems and an aircraft context which includes the configuration and type of aircraft used, as well as its operational status.

[0008] Typically, in civil aviation, airlines and / or external suppliers have calculation systems to provide a flight plan and expected aircraft performance, for example, a required fuel quantity.

[0009] In business aviation, the constraints on crews are significant and specific. Customers sometimes require crews to meet more stringent mission criteria, such as passenger comfort during the flight, the ability to connect to satellite transmission systems, the aircraft's weight, etc.

[0010] In addition, mission conditions, including take-off times, are subject to change and the destination may change quickly depending on the passengers' specific needs.

[0011] In this context, existing flight plan supply systems are not entirely satisfactory.

[0012] In particular, these systems are designed to operate on a sum of input criteria (speed, flight level, number of passengers, etc.) to which a single navigation solution will correspond. It is therefore frequently necessary to carry out several iterations to adjust the mission hypotheses.

[0013] The results obtained by flight plan provider systems are also generally incomplete with regard to the criteria required to carry out the mission, particularly in the management of customer criteria, aircraft context and performance.

[0014] Therefore, the trajectory solutions proposed by the supplier are not satisfactory for the customer and / or result in non-optimal flight time and / or increased fuel consumption.

[0015] FR 3 032 271 describes a mission calculation system which establishes in a horizontal plane iso-cost curves for aircraft movement. This system does not deal with vertical optimization.

[0016] An aim of the invention is therefore to provide an aircraft mission calculation system which allows the crew to easily find a trajectory which is optimized both horizontally and vertically, taking into account the current state of the aircraft, the criteria imposed by the customer, and the constraints of the mission volume, in particular in the vertical plane.

[0017] For this purpose, the invention relates to a system according to claim 1.

[0018] The system according to the invention may comprise one or more of the characteristics of claims 2 to 10, taken in isolation or in any technically possible combination.

[0019] The invention also relates to a method for calculating the mission of an aircraft, according to claim 11.

[0020] The invention will be better understood by reading the following description, given solely by way of example, and made with reference to the appended drawings, in which: [ Fig 1 ] there figure 1 is a block diagram illustrating a first mission calculation system according to the invention [ Fig 2 ] there figure 2 is a schematic top view illustrating, at several flight levels, the determination of a plurality of isochronous curves after several displacement increments [ Fig 3 ] there figure 3 is a view of the vertical profile of the movements of the aircraft at separate levels, for determining isochronous curves with a view to establishing a point on an extended isochronous curve at a given flight level; [ Fig 4 ] there figure 4 is a view analogous to the figure 3 , illustrating the section in a vertical plane of an avoidance zone; [ Fig 5 ] there figure 5 is a view analogous to the figure 2 , for a given flight level, illustrating the obtaining of an extended isochronous curve; [ Fig 6 ] there figure 6 is a view analogous to the figure 2 , illustrating several extended isochronous curves obtained at several flight levels, for the same displacement interval; [ Fig 7 ] there figure 7 is a view analogous to the figure 6 , illustrating at several flight levels, the determination of a plurality of isochrone curves from the extended isochrones; [ Fig 8 ] there figure 8 is a view analogous to the figure 7 , illustrating the determination of the extended isochronous curves at each of the flight levels at a second displacement interval; [ Fig 9 ] there figure 9 is a view analogous to the figure 8 , the extended isochronous curves having been determined; [ Fig 10 ] there figure 10 is a view analogous to the figure 2 , illustrating the obtaining of a trajectory between a starting geographic point and a destination geographic point; [ Fig 11 ] there figure 11 illustrates a vertical profile of the trajectory; [ Fig 12 ] there figure 12 illustrates the trajectories obtained using extended isochronous curves, or using extended iso-fuel consumption curves; [ Fig 13 ] there figure 13 illustrates a variant of the invention illustrating the principle of transition from a free trajectory to a trajectory constrained by air routes; [ Fig 14 ] there figure 14 is a schematic view of a second mission calculation system according to the invention.

[0021] A first mission calculation system 10 according to the invention, which, in this example, is present in the cockpit 12 of an aircraft, is illustrated by the figure 1 .

[0022] The aircraft is preferably a civil aircraft, in particular a business jet.

[0023] In a known manner, the cockpit 12 of the aircraft is intended to control all of the aircraft's systems during its use.

[0024] The cockpit 12 includes in particular, in addition to the mission calculation system 10, a system 14 for controlling the flight of the aircraft cockpit (“Flight Management System” in English or “FMS”), and a system 16 for managing and monitoring the various aircraft systems.

[0025] The flight control system 14 is intended to assist the pilot of the aircraft in navigating the aircraft during a mission. It is capable of providing information, in particular, on the route followed by the aircraft, and on aircraft performance parameters such as fuel consumption.

[0026] It is also suitable for guiding the aircraft to make it follow a predetermined trajectory between a first geographical point 18 of origin and a second geographical point 20 of destination (shown schematically on the figure 2 ).

[0027] The system 16 for managing and monitoring the various aircraft systems is intended in particular to allow the crew to monitor and possibly pilot all of the aircraft systems. It is particularly suitable for determining an operating state of the aircraft, in particular the presence of faults and breakdowns present on the aircraft on the ground and / or in flight. As will be seen below, the mission calculation system 10 according to the invention is connected to the management system 16 to take into account the state of the aircraft in the mission calculations.

[0028] The mission carried out by the aircraft includes at least one step 22 (or “leg”), represented schematically on the figure 12 , between a first geographical point 18 of origin and a second geographical point 20 of destination. In certain cases (not shown), the mission carried out by the aircraft comprises a plurality of successive stages 22, the second geographical point 20 of destination of a first stage constituting the first geographical point 18 of origin of a second stage.

[0029] The mission is carried out following operational specifications which include in particular a mission context and an aircraft context.

[0030] The mission context includes, for example, at least one operating constraint, in particular a number of passengers to be transported, a maximum take-off weight linked in particular to an available runway length, a navigation fuel load, a reserve fuel load, an imposed departure time and / or arrival time, a maximum distance to be covered, and / or a distance to an alternative terrain en route.

[0031] In reference to the figure 12 , the mission context advantageously includes navigation constraints, such as for example 24 zones or prohibited flight levels, 26 air routes or imposed flight levels, or more generally free flight zones and / or flight zones imposed by airways.

[0032] The mission context advantageously includes meteorological constraints such as zones 28 of dangerous meteorological phenomena, notably the formation of frost or cumulonimbus.

[0033] The mission context possibly also includes passenger comfort constraints, in particular turbulence zones 30 to be avoided, in particular depending on a desired level of turbulence, chosen for example from a low level, a medium level, and a high level of turbulence, or satellite telecommunication coverage zones 32 to allow telecommunication between the aircraft and the outside world, in particular on the ground, in particular chosen from a low level, a medium level and a good level of communication possibility.

[0034] In this example, the different zones 24, 28, 30, 32 are preferably defined by horizontal coordinates (for example latitude and longitude) and by vertical altitude coordinates. The position of these zones advantageously evolves over time. In this case, the aforementioned coordinates evolve temporally, defining a four-dimensional (or 4D) avoidance zone or, on the contrary, a four-dimensional zone of desired or constrained passage.

[0035] Zones 24, 28, 30, 32 therefore define, in the horizontal plane illustrated on the figure 12 , horizontal avoidance sections or, on the contrary, horizontal sections of desired or constrained passage. They also define, in the vertical plane illustrated on the figure 11 , vertical avoidance sections or, on the contrary, vertical sections of desired or constrained passage. The position of zones 24, 28, 30, 32 evolves advantageously over time.

[0036] The aircraft context may include usage constraints linked to departure authorizations (or "dispatch") and / or constraints linked to a particular state of the aircraft in terms of faults and / or breakdowns on one or more aircraft equipment.

[0037] For example, a departure clearance related to certain aircraft defects may impose a maximum flight level and / or a maximum speed. A failure to retract the landing gear or a flap may also impose an increased fuel consumption constraint.

[0038] The mission calculation system 10 is intended to establish a trajectory of the aircraft to carry out step 22 between at least a first geographical point 18 of origin and at least a second geographical point 20 of destination, taking into account the operational specifications, and in particular the mission context and the aircraft context, while following the existing air routes.

[0039] The trajectory obtained through the mission calculation system 10 includes the aircraft's route in latitude and longitude, with a vertical flight profile, defined by one or more altitudes and passage times. The route is therefore determined in four dimensions.

[0040] Advantageously, the mission calculation system 10 is also capable of establishing flight plan parameters, in particular the weight and balance of the aircraft, the takeoff and landing card (i.e. the flight data for the pilot relating to guidance such as the speeds V1, V2, VR on the runway, the acceleration on release of the brakes, the engine speed on takeoff, and / or the attitude on takeoff), the calculation of the limit weights on takeoff and landing, the meteorology at low speed (i.e. on the surface) and at high speed (i.e. en route), the air traffic control information (ATIS broadcast service for “Automated Terminal Information Service”, e-NOTAM for “Notice to airmen”, telecommunications frequency, FIRS for “Flight Information RegionS”, air traffic control center), and / or the alternative terrains available at the destination, and en route.

[0041] In reference to the figure 1 , the mission calculation system 10 comprises a calculation engine 40 and advantageously, a user interface 42 for configuration and restitution forming a mission platform.

[0042] The user interface 42 comprises, for example, at least one screen 44, and at least one member 46 for selecting and entering information by the user, which may be a real or virtual keyboard, a mouse and / or a touch system.

[0043] The user interface 42 is capable of allowing the user to enter at least part of the operational specifications, in particular the geographical points 18, 20 of origin and destination, waypoints, desired times, desired loads, maximum wind on the trajectory, etc.

[0044] It is advantageously suitable for allowing the user to define at least part of the mission context, in particular the navigation and passenger comfort constraints, and / or to define at least part of the aircraft context.

[0045] An example of interface 42 is described in the French patent application entitled “Aircraft mission calculation system, comprising a mission board and associated method” filed under number 17 01234 by the Applicant.

[0046] The calculation engine 40 is connected to the interface 42. It is advantageously also connected to the flight control system 14, to the management and monitoring system 16.

[0047] It is suitable for querying a meteorological database 50 and / or a navigation information database 52, for example via a data network, in particular a wireless data network.

[0048] The weather database 50 contains current and predictive weather data in the navigation area of ​​the aircraft in a mission volume extending between the origin point 18 and the destination point 20. The mission volume preferably has a significant width, for example at least 700 nautical miles, on either side of the great circle trajectory 90 between the origin point 18 and the destination point 20.

[0049] This weather data is provided at several flight levels, for example every 304 m (1000 ft), at an altitude ranging for example from 0 m to 15545 m (51000 ft).

[0050] The weather data is provided at altitude but also by providing a weather component that evolves over time. This evolving component is obtained using weather forecast data, which may include a plurality of weather maps at successive instants in time (e.g., every hour).

[0051] These meteorological data include in particular wind speed and direction, temperature, pressure, precipitation, dangerous phenomena (frost, thunderstorms / cumulonimbus), turbulence, tropopause level, volcanic ash clouds, dust / sand clouds, visibility, as well as aeronautical observations in the area or en route (METAR, PIREPS) and forecasts in the area (TAF)... They may include the definition and evolution in time and space of the geographical coordinates of zones 28 of dangerous meteorological phenomena and / or zones of turbulence 30.

[0052] These meteorological data define a meteorological context, preferably evolving, in the mission volume extending between the geographical point of origin 18 and the geographical point of destination 20.

[0053] The navigation information database 52 contains information data on the terrain at the point of origin 18 and at the point of destination 20, and between these points 18, 20. The navigation information database 52 advantageously comprises an airport sub-database (runway lengths, orientation of the runways, slopes, etc.) and a navigation sub-database. The navigation data notably include a network of waypoints 53A (or "waypoints") and the trajectories 53B imposed between the waypoints, as defined by the aviation authorities in each country (see figure 13 ).

[0054] It advantageously contains the definition of the geographical coordinates of prohibited zones and / or flight levels 24, in particular due to geopolitical data, and / or imposed air routes 26.

[0055] It may include the definition of 32 satellite telecommunications (SATCOM) coverage areas.

[0056] The calculation engine 40 comprises at least one calculator comprising at least one processor 54 and a memory 56. The memory 56 contains software modules capable of being executed by the processor 54. Alternatively, the modules are produced at least partially in the form of programmable logic components, or in the form of dedicated integrated circuits.

[0057] In this example, the memory 56 contains a software module 58 for initializing mission specifications, capable of acquiring operational specifications of the mission from in particular the interface 42, and comprising a software module 60 for recovering a meteorological context from the database 50, and a software module 62 for determining aircraft performance, as a function of the mission specifications, the meteorological context and the aircraft context.

[0058] According to the invention, the memory 56 also contains a first software module 64 for calculating a first optimal mission trajectory 64A, as a function of the determined aircraft performance, the meteorological context and the mission specifications, the first calculation module 64 being able to calculate the first optimal mission trajectory 64A in a manner not constrained by a network of waypoints 53A and / or trajectories 53B imposed between the waypoints 53A.

[0059] Advantageously, as described in French application No. 1800734, the memory 56 also contains a module 63 for defining, around the first optimal mission trajectory 64A, an optimization region 63A of the optimal trajectory 64A and a second module 65 for calculating an optimized trajectory 65A of the aircraft in the optimization region 63A, in a manner constrained by a network of waypoints 53A and / or trajectories 53B imposed between the waypoints 53A.

[0060] The initialization module 58 is capable of acquiring the operational specifications of the mission from the interface 42, and / or the management and monitoring system 16.

[0061] The recovery module 60 is capable of interrogating the meteorological database 50 to obtain in particular the wind speeds and directions in the mission volume extending between the origin point 18 and the destination point 20, at several flight levels.

[0062] The determination module 62 comprises a software application 66 for determining the weight and balance of the aircraft, intended to determine the center of gravity of the aircraft, a software application 68 for determining high-speed performance, and advantageously a software application 70 for determining low-speed performance.

[0063] Application 66 for determining the weight and balance of the aircraft is capable of determining the position of the center of gravity of the aircraft in the absence of fuel in the aircraft (or "Zero Fuel Weight Center of Gravity") and the mass of the aircraft in the absence of fuel in the aircraft (or "Zero Fuel Weight"), as a function of the empty mass of the aircraft, the equipment on board the aircraft, the passengers and / or the cargo on board, and their position in the aircraft, as well as monitoring the flight envelope of the aircraft (mass-balance diagram).

[0064] The high-speed performance determination application 68 is suitable for determining the mass of fuel to be loaded into the aircraft on a given trajectory, for example an orthodromic trajectory 90 (see figure 12 ) between the point of origin 18 and the point of destination 20, using the position of the center of gravity and the mass of the aircraft in the absence of fuel in the aircraft (or “Zero Fuel Weight”) determined by the application 66, a predetermined air speed, for example entered or calculated from the data entered by the user interface 42, the meteorological context retrieved from the module 60, in particular wind speeds and temperatures and possibly the aircraft context, for example the type and age of the engines, retrieved from the initialization module 58.

[0065] The high-speed performance determination application 68 further comprises functions for calculating instantaneous fuel consumption and variation of the instantaneous aircraft mass during a trajectory, advantageously using the position of the center of gravity and the mass of the aircraft in the absence of fuel in the aircraft, a predetermined air speed, for example entered or calculated from the data entered by the user interface 42, the meteorological context retrieved from the module 60, in particular wind speeds and temperatures and possibly the aircraft context, for example the type and age of the engines, retrieved from the initialization module 58.

[0066] The high-speed performance determination application 68 also includes a function for determining the achievable flight levels based on the predetermined airspeed, the meteorological context, and possibly the aircraft context.

[0067] These functions for calculating instantaneous consumption, variation in instantaneous aircraft weight and determination of achievable flight levels are suitable for being called by the calculation module 64 for calculating iso-displacement curves.

[0068] The low speed performance determination application 70 is capable of determining in particular the maximum weight of the aircraft (and the takeoff card) allowing the aircraft to take off and / or land on a field, based on runway length data retrieved from the database 52, and the meteorological context retrieved from the module 60.

[0069] According to the invention, the first calculation module 64 is configured to calculate, from at least one chosen point 78 accessible to the aircraft, a plurality of iso-displacement curves 79, 80, 81 each corresponding to a displacement of the aircraft at a distinct flight level (for example FL300, FL350, FL400), after one or more displacement increments. The number of levels is equal to 3 in the example shown. In practice, the number of levels is greater than or equal to 2 and is for example between 2 and 20, advantageously between 6 and 20.

[0070] The first calculation module 64 is capable of determining, on the basis of the iso-displacement curves 79, 80, 81 obtained at the same displacement interval corresponding to several displacement increments at different flight levels FL300, FL350, FL400, at least one extended iso-displacement curve 83, maximizing the displacement carried out from the geographical point of origin 18 or minimizing the displacement to be carried out to the geographical point of destination 20.

[0071] The first calculation module 64 is furthermore capable of calculating at least one optimal trajectory 64A between the origin point 18 and the destination point 20 on the basis of the extended iso-displacement curves 83.

[0072] The chosen accessible point 78 is initially the original geographic point 18, as illustrated by the figure 2 . Alternatively, the accessible point chosen is an end point of ascent from the geographical point of origin 18.

[0073] Once at least one extended iso-displacement curve 83 is obtained, each iso-displacement curve 79, 80, 81 is obtained from accessible points 78 located on the extended iso-displacement curve 83, as illustrated by the figure 7 .

[0074] In the example illustrated by the figures, the first calculation module 64 is capable, from the original geographical point 18 or from any point of an extended iso-displacement curve 83, of establishing at least one iso-displacement curve 79, 80, 81 over a predetermined time increment from the chosen point, taking into account the chosen air speed, the meteorological context, the aircraft performances determined by calculation functions of the application 68, and the operational specifications defined by the initialization module 58.

[0075] In reference to the figure 3 , the iso-displacement curves 79, 80, 81 are obtained for a given flight level, here FL300, for movements of the aircraft in level flight at departure flight levels FL300, FL350, FL400 equal to or distinct from the given flight level FL300 from an accessible point here located on an iso-displacement curve 83 of the respective departure flight level FL300, FL350, FL400.

[0076] Thus, the iso-displacement curve 79 is obtained by moving the aircraft at a constant level corresponding to the given flight level FL300, from an accessible point on the extended iso-displacement curve 83 at the departure flight level FL300 which corresponds to the given flight level FL300.

[0077] The iso-displacement curves 80 and 81 are obtained by performing a phase 84 of level flight at a departure flight level FL350, FL400 distinct from the given flight level FL300, starting from the iso-displacement curve 83 at the respective departure flight level FL350, FL400, then a phase 85 of reaching the given flight level FL300.

[0078] The reaching phase 85 comprises for example a climb or a descent following a predetermined profile, for example at constant slope, at constant true air speed or at constant Mach to reach the given flight level FL300 from the level flight carried out at a flight level FL350, FL400 distinct from the given flight level FL300.

[0079] Advantageously, for a given movement interval corresponding to several movement increments, the calculation module 64 is able to determine an intermediate increment from which the reaching phase 85 starts, by determining for example the time necessary to reach the given flight level FL300 from the respective starting flight level FL350, FL400.

[0080] This intermediate increment is determined based on the flight profile predetermined in phase 85, taking into account the air speed chosen, the meteorological context, the aircraft performance determined by the calculation functions of applications 66 and 68, and the operational specifications defined by the initialization module 58.

[0081] The calculation module 64 is then capable of determining an intermediate iso-displacement curve, at the intermediate increment, for level flight at the departure flight level FL350, FL400, then of defining the iso-displacement curves 80, 81 at the given flight level FL300 resulting from the reaching phase 85, at the displacement interval, from the intermediate iso-displacement curve defined previously.

[0082] As illustrated by the figure 5 and by the figure 6 , the extended iso-displacement curve 83 is obtained by superimposing the iso-displacement curves 79, 80, 81 obtained at the same displacement interval, then determining the location of the points on the iso-displacement curves 79, 80, 81 maximizing the distance traveled from the starting geographic point 18 or minimizing the distance to be traveled to the arrival geographic point 20.

[0083] So, in a first direction, left on the figure 5 , the point 86A furthest from the chosen point 78 is located on the iso-displacement curve 79 corresponding to level flight at the given flight level FL300. On the contrary, in the direction to the right on the figure 5 , the point 86B furthest from the chosen point 78 is a point on the iso-displacement curve 81 corresponding to a movement of the aircraft in level flight at a flight level FL400 distinct from the given flight level FL300, and then in descent following the predetermined profile towards the given flight level FL300.

[0084] The points 86A, 86B of the extended iso-displacement curve 83 thus formed are therefore advantageously located on several iso-displacement curves 79, 80, 81 to maximize the total distance traveled from the geographical point of origin 18 or to minimize the total distance to the geographical point of destination 20.

[0085] The first calculation module 64 is capable of selectively excluding points which are located in prohibited flight zones or levels 24, in zones 28 of dangerous meteorological phenomena and / or in turbulence zones 30. The calculation module 24 is also capable of excluding points which are not located in a satellite coverage zone 32.

[0086] The avoidances made from the defined four-dimensional zones are illustrated for example on the figure 13 in section in the horizontal plane, and on the figure 4 in section in the vertical plane.

[0087] As visible on the figure 10 , the first calculation module 64 is capable of determining a plurality of successive extended iso-displacement curves 83, obtained at successive time intervals, from iso-displacement curves 79, 80, 81 each corresponding to one or more time increments within each displacement interval.

[0088] Advantageously, as shown in the figure 10 , the first calculation module 64 is capable of determining the successive extended iso-displacement curves 83 at several flight levels FL300, FL350, FL400.

[0089] The first calculation module 64 is capable of choosing an optimal trajectory 64A based on the calculated extended iso-displacement curves 83.

[0090] In reference to the figure 13 , the first calculation module 64 is capable of determining each point of the optimal trajectory 64A in a manner not constrained by a network of passage points 53A and / or trajectories 53B imposed between the passage points 53A.

[0091] Thus, the determination of the optimal trajectory 64A by the first calculation module 64 is implemented as if the aircraft were capable of performing a free flight taking into account the mission specifications, but without taking into account the network of waypoints 53A and / or trajectories 53B imposed between the waypoints 53A which are defined by the air traffic control authorities.

[0092] In reference to the figure 10 , the optimal trajectory 64A is preferably determined from the geographical destination point 20, or from a descent start point towards the point 20, by going up the iso-displacement curves 80 at the final flight level FL350 having made it possible to first reach the geographical destination point 20 or the descent start point, up to the point 87A of the extended iso-displacement curve 83 corresponding to the last displacement interval composed of several iso-displacement increments. This defines a first trajectory section 88A.

[0093] Point 87A of the extended iso-displacement curve 83 corresponds to a point of an iso-displacement curve 79, 80, 81 which results either from level flight at the same flight level as the final flight level FL350, or from a phase 84 of level flight at a flight level FL300, FL400 different from the final flight level FL350 and from a phase 85 of reaching the final flight level.

[0094] In the second case, shown on the right on the figure 10 , the iso-displacement curves 81 at a separate flight level FL400 are then traced back to point 87B of the adjacent extended iso-displacement curve 83 at the same flight level FL400 from which point 87A was obtained. This defines a second trajectory section 88B.

[0095] In the first case, represented by point 87B on the figure 10 , the iso-displacement curves 80 at the same flight level FL400 are traced back to point 87C of the adjacent extended iso-displacement curve 83 at the same flight level FL400 from which point 87B was obtained. This defines a third trajectory section 88C. Point 87C was here obtained from a phase 84 of level flight at flight level FL300 followed by a phase 85 of climb to flight level FL400.

[0096] This mechanism is repeated until reaching the geographic origin point 18, as illustrated on the left in the figure 10 .

[0097] The first calculation module 64 is capable of thus defining an optimal trajectory 64A not only in the horizontal plane, but also in the vertical plane.

[0098] The trajectory profile in the vertical plane is illustrated in the figure 11 and comprises a plurality of trajectory sections 88A to 88D. Each trajectory section 88A, 88B, 88C is determined from and / or from an extended iso-displacement curve 83, and comprises either a single plateau phase 84, or a plateau phase 84, and a phase 85 of reaching another plateau.

[0099] The trajectory profile in the horizontal plane is illustrated in the figure 12 .

[0100] In this example, iso-displacement curves are advantageously isochronous curves. By definition, an isochronous curve is a curve connecting the points accessible to the aircraft from a given point (which may be the origin point 18 or a point on an extended isochronous curve 83) in a given time which corresponds to one or more time increments. Each time increment is for example between 1 minute and 1 hour, in particular between 2 minutes and 10 minutes, for example 5 minutes.

[0101] In this example, each isochronous curve is determined from a given point by calculating from the given point all the points accessible to the aircraft, at a given air speed, taking into account the meteorological context, in particular the direction and intensity of the wind, as provided by the recovery module 60 and the aircraft performance, as determined by the calculation functions of the application 68.

[0102] Advantageously, the calculation module 64 is capable of calculating a succession of isochronous curves 79, 80, 81 at several flight stages, and extended isochronous curves 83 from the isochronous curves 79, 80, 81 obtained for the same time interval.

[0103] In reference to the figure 13 , the definition module 63 is advantageously capable of defining the optimization region 63A of the trajectory as a function of a predetermined lateral distance at each point of the optimal trajectory 64A defined by the first calculation module 64 and as a function of the operational mission specifications, in particular the mission context, in particular navigation constraints, meteorological constraints, and passenger comfort constraints.

[0104] Advantageously, the definition module 63 is capable of laterally delimiting the optimization region 63A of the trajectory 64A by lateral limits extending laterally at a distance chosen as a function of the density of the aerial network of each point of the optimal trajectory 64A.

[0105] This chosen distance is generally less than 1852 km (1000 nautical miles or "nm") and can be between 185 km (100 nm) and 926 km (500 nm) in a low density network, for example in Africa, and between 183 km (99 nm) and 55 km (30 nm) in a high density network such as in Europe.

[0106] Thus, the optimization region 63A is generally defined by a band encompassing the trajectory 64A. The band is potentially also constrained by prohibited flight zones 24, by zones 28 of dangerous meteorological phenomena and / or by zones of turbulence 30. It encompasses, as the case may be, satellite coverage zones 32.

[0107] The second trajectory calculation module 65A comprises an application 92 for defining a network of nodes between the geographical point of origin 18 and the geographical point of destination 20 from the network of waypoints 53A and / or trajectories 53B imposed between the waypoints 53A, and an application 93 for defining a cost associated with the passage from a node to an adjacent node among the nodes of the network.

[0108] The second calculation module 65 also comprises an application 98 for determining the optimized trajectory 65A in the network of nodes on the basis of a minimization of the total cumulative cost between the geographical point of origin 18 and the geographical point of destination 20.

[0109] The definition application 92 is capable of loading the coordinates of waypoints 53A and of trajectories 53B imposed between the waypoints 53A from the database 52, within the optimization region 63A.

[0110] The definition application 92 is suitable for defining, among the waypoints 53A, the nodes which are the possible waypoints 53A for the aircraft, taking into account in particular the mission constraints, in particular the navigation constraints, the meteorological constraints, and the passenger comfort constraints, as defined above.

[0111] The definition application 93 is capable of defining the cost associated with the passage between two adjacent nodes on the basis of the geographical distance separating the two nodes and also of the meteorological context recovered from the module 60, in particular the evolving meteorological context and possibly the aircraft context, for example the type and age of the engines, recovered from the initialization module 58.

[0112] The application 98 for determining the optimized trajectory 65A is capable of implementing a cost minimization algorithm to define the least costly trajectory in the optimization region 63A passing through the nodes and through the trajectories imposed between the nodes, from the geographical point of origin 18 to the geographical point of destination 20.

[0113] The algorithm is for example a Dijkstra algorithm and / or an A* algorithm. The Dijkstra algorithm takes as input the weighted network defined above between the origin geographic point 18 and the destination geographic point 20.

[0114] A description of the use of Dijkstra's algorithm is given in French patent application No. 1800734.

[0115] A description of the A* algorithm is for example given in the article downloadable at the following address: https: / / fr.wikipedia.org / wiki / Algorithme_A*.

[0116] Once the optimized trajectory 65A has been obtained, the calculation engine 40 is advantageously capable of determining at least one mission parameter of the aircraft corresponding to the optimized trajectory 65A.

[0117] The mission parameter is for example a total takeoff weight of the aircraft. This takeoff weight is calculated at each iteration by the calculation module 64 then by the calculation module 65, on the basis of the estimated consumption on the trajectory between the point of origin 18 and the point of destination 20, calculated using the functions for calculating the instantaneous fuel consumption and variation of the instantaneous aircraft weight, and on the basis of a passenger and freight load predefined in the operational specifications.

[0118] The calculation engine 40 is then capable of carrying out calculation iterations successively using the modules 64, 65, by determining, in each iteration, a new optimal trajectory 64A using the first calculation module 64 by calculating new extended iso-displacement curves 83, a new optimization region 63A using the determination module 63, then a new optimized trajectory 65A using the second calculation module 65, until convergence is reached on the value of the mission parameter.

[0119] Once convergence has been obtained, the mission engine 40 is capable of verifying the consistency of the high-speed performance using the application 66. The mission engine 40 is capable of verifying in particular that the takeoff weight obtained using the calculation modules 64, 65 after convergence is less than or equal to the maximum weight allowing the aircraft to take off obtained using the low-speed application 70 to ensure that the aircraft will be able to take off on the terrain chosen for takeoff.

[0120] Once the final optimized trajectory 65A has been obtained, the second calculation module 65 provides a data file comprising a list of waypoints 53A, and a list of trajectories 53B between the waypoints 53A.

[0121] The data file provided by the second calculation module 65 further advantageously comprises a list of headings TCA between the waypoints 53A, a list of distances DST between the waypoints 53A, a list of wind components COMP between the waypoints 53A, a list of true speeds TAS between the waypoints 53A, a list of ground speeds GS between the waypoints 53A, a list of static air temperatures SAT between the waypoints 53A, a list of turbulence levels SHR between the waypoints 53A, a list of estimated arrival times ETA at a waypoint 53A, and a list of estimated en route times EET.

[0122] This data file is suitable for retrieval by the crew and / or for loading by manual entry or data transfer into the flight control system 14, for use during the flight.

[0123] A method for calculating a mission, implemented using the system 10 according to the invention, will now be described.

[0124] This process is implemented, for example, during mission preparation, to establish its feasibility, to prepare the mission more precisely, or to take into account a last-minute change in a mission already prepared.

[0125] Alternatively, this process is implemented during mission monitoring, or to test mission modification hypotheses, to optimize it, or to reconfigure it.

[0126] Initially, the user, in particular the crew, enters at least part of the operational specifications using the configuration interface 42. The user defines, for example, for each stage of the mission, the geographical point of origin 18, the geographical point of destination 20 and possibly a number of passengers to be transported, a desired air speed, a departure time and / or an imposed arrival time, a maximum distance to be covered.

[0127] Then, when it wishes to define a possible trajectory, it activates the calculation engine 40. The initialization module 58 retrieves the operational specifications from the interface 42 in particular to obtain all the information on each stage of the mission.

[0128] The initialization module 58 advantageously retrieves other operational specifications from the aircraft management and tracking system 16.

[0129] This step initializes the operational specifications related to the mission context and the aircraft context, for example the presence of breakdowns or departure authorizations. This step also initializes the operational specifications for passenger comfort, particularly in terms of connectivity and turbulence level. This step of specifying acceptable weather data is advantageously done at the user interface 42.

[0130] Initialization is advantageously done by considering a purely orthodromic trajectory in standard atmosphere (“perfect” flight data).

[0131] Then, the meteorological context recovery module 60 queries the meteorological database 50 to obtain in particular the wind speeds and directions between the origin point 18 and the destination point 20, at several flight levels.

[0132] The aircraft performance determination module 62 is then activated. The weight and balance determination application 66 determines the weight of the aircraft and the position of the center of gravity of the aircraft in the absence of fuel in the aircraft (“Zero Fuel Weight” and “Zero Fuel Weight Center of Gravity”), based on the empty weight of the aircraft, the equipment on board the aircraft, the passengers and / or the cargo on board, and their position in the aircraft.

[0133] On this basis, on the basis of the meteorological context retrieved by the retrieval module 60, on the basis of the aircraft context retrieved from the initialization module 58, and on the basis of the desired air speed, the high-speed performance determination application 68 determines an initial trajectory 90 of the aircraft and the associated aircraft consumption using the position of the center of gravity determined by the application 66.

[0134] Application 68 then calculates all the mission parameters, in particular the route, arrival time, flight profile, and fuel consumption, which makes it possible to deduce the takeoff weight in particular.

[0135] The first calculation module 64 then calculates from at least one chosen point 78 accessible to the aircraft, a plurality of iso-displacement curves 79, 80, 81 each corresponding to a displacement of the aircraft at a distinct flight level (for example FL300, FL350, FL400), after one or more displacement increments.

[0136] The first calculation module 64 then determines, on the basis of the iso-displacement curves 79, 80, 81 obtained at the same displacement interval corresponding to several displacement increments at different flight levels FL300, FL350, FL400, at least one extended iso-displacement curve 83, maximizing the displacement carried out from the geographical point of origin 18 or minimizing the displacement to be carried out towards the geographical point of destination 20.

[0137] The first calculation module 64 then calculates at least one optimal trajectory 64A between the origin point 18 and the destination point 20 on the basis of the extended iso-displacement curves 83.

[0138] The chosen accessible point 78 is initially the original geographic point 18, as illustrated by the figure 2 . Alternatively, the accessible point chosen is an end point of ascent from the geographical point of origin 18.

[0139] Once at least one extended iso-displacement curve 83 is obtained, each iso-displacement curve 79, 80, 81 is obtained from accessible points 78 located on the extended iso-displacement curve 83, as illustrated by the figure 7 .

[0140] In the example illustrated by the figures, from the geographical point of origin 18 or from any point of an extended iso-displacement curve 83 the first calculation module 64 establishes at least one iso-displacement curve 79, 80, 81 over a predetermined time increment from the chosen point, taking into account the chosen air speed, the meteorological context, the aircraft performances determined by the functions for calculating instantaneous fuel consumption and variation of the instantaneous aircraft mass and for determining the achievable flight levels described above, and the operational specifications defined by the initialization module 58.

[0141] The first calculation module 64 is capable of selectively excluding points which are located in prohibited flight zones or levels 24, in zones 28 of dangerous meteorological phenomena and / or in turbulence zones 30. The calculation module 24 is also capable of excluding points which are not located in a satellite coverage zone 32.

[0142] In reference to the figure 3 , the iso-displacement curves 79, 80, 81 are obtained for a given flight level, here FL300, for movements of the aircraft at levels at departure flight levels FL300, FL350, FL400 equal to or distinct from the given flight level FL300 from an accessible point here located on an iso-displacement curve 83 of the respective departure flight level FL300, FL350, FL400.

[0143] So, on the figure 3 , the iso-displacement curve 79 is obtained by moving the aircraft at a constant level corresponding to the given flight level FL300, from an accessible point on the extended iso-displacement curve 83 at the departure flight level FL300 which corresponds to the given flight level FL300.

[0144] The iso-displacement curves 80 and 81 are obtained by performing a phase 84 of level flight at a departure flight level FL350, FL400 distinct from the given flight level FL300, starting from the iso-displacement curve 83 at the respective departure flight level FL350, FL400, then a phase of reaching the given flight level FL300.

[0145] The reaching phase 85 comprises for example a climb or a descent following the predetermined profile to reach the given flight level FL300 from the level flight carried out at a flight level FL350, FL400 distinct from the given flight level FL300.

[0146] Advantageously, for a given movement interval corresponding to several movement increments, the calculation module 64 determines an intermediate increment from which the reaching phase 85 starts, by determining for example the time necessary to reach the given flight level FL300 from the respective starting flight level FL350, FL400. This intermediate increment is determined as a function of the flight profile predetermined in the phase 85, taking into account the air speed chosen, the meteorological context, the aircraft performances determined by calculation functions of the applications 66 and 68, and the operational specifications defined by the initialization module 58.

[0147] The calculation module 64 then determines an intermediate iso-displacement curve, at the intermediate increment for level flight at the departure flight level FL350, FL400, then defines the iso-displacement curve 80, 81 at the given flight level FL300 resulting from the reaching phase 85, at the displacement interval, from the intermediate iso-displacement curve defined previously.

[0148] As illustrated by the figure 5 and by the figure 6 , the extended iso-displacement curve 83 is obtained by superimposing the iso-displacement curves 79, 80, 81 obtained at the same displacement interval, then determining the location of the points on the iso-displacement curves 79, 80, 81 maximizing the distance traveled from the starting geographic point 18.

[0149] The points 86A, 86B of the extended iso-displacement curve 83 thus formed are therefore advantageously located on several iso-displacement curves 79, 80, 81 to maximize the distance traveled from the geographical point of origin 18 or minimize the distance to be traveled to the geographical point of destination 20.

[0150] As visible on the figure 10 , the first calculation module 64 determines a plurality of successive extended iso-displacement curves 83, obtained at successive time intervals, from iso-displacement curves 79, 80, 81 each corresponding to one or more time increments within each displacement interval.

[0151] Advantageously, as shown in the figure 10 , the first calculation module 64 determines the successive extended iso-displacement curves 83 at several flight levels FL300, FL350, FL400.

[0152] The first calculation module 64 then defines an optimal trajectory 64A based on the determined extended iso-displacement curves 83 and a total takeoff weight of the aircraft corresponding to this optimal trajectory 64A.

[0153] The first calculation module 64 determines each point of the optimal trajectory 64A in an unconstrained manner by a network of waypoints 53A and / or trajectories 53B imposed between the waypoints 53A.

[0154] In reference to the figure 10 , the optimal trajectory 64A is preferably determined from the geographical destination point 20, or from a descent start point towards the point 20, by going up the iso-displacement curves 80 at the final flight level FL350 having made it possible to first reach the geographical destination point 20 or the descent start point, up to the point 87A of the extended iso-displacement curve 83 corresponding to the last displacement interval composed of several iso-displacement increments. This defines a first trajectory section 88A

[0155] Point 87A of the extended iso-displacement curve 83 corresponds to a point of an iso-displacement curve 79, 80, 81 which results either from level flight at the same flight level as the final flight level FL350, or from a phase 84 of level flight at a flight level FL300, FL400 different from the final flight level FL350 and from a phase 85 of reaching the final flight level.

[0156] In the second case, shown on the right on the figure 10 , the iso-displacement curves 81 at a separate flight level FL400 are then traced back to point 87B of the adjacent extended iso-displacement curve 83 at the same flight level FL400 that led to point 87A. This defines a second trajectory section 88B.

[0157] In the first case, represented by point 87B on the figure 10 , the iso-displacement curves 80 at the same flight level FL400 are traced back to point 87C of the adjacent extended iso-displacement curve 83 at the same flight level FL400 having made it possible to reach point 87B. This defines a third trajectory section 88C.

[0158] This is repeated until reaching the original geographic point 18, as shown on the left in the figure 10 .

[0159] The optimal trajectory 64A and the corresponding mass of the aircraft at take-off are obtained in a simple manner, greatly limiting the number of calculations and tests to be carried out, thanks to the use of the extended iso-displacement curves 83.

[0160] These curves 83 in fact avoid having to determine multiple combinations of flight levels, by directly integrating the points which led to the maximum distance traveled independently of the flight profile. In addition, the intermediate determination of the iso-displacement curves 79, 80, 81 takes into account the zones to be avoided or on the contrary to be favored both in the horizontal plane and in the vertical plane.

[0161] Thus, the route and performance calculation are more integrated, leading to fewer iterations. Furthermore, taking into account the phases 85 of reaching the level by the first calculation module 84 makes the calculation more efficient and closer to reality.

[0162] In this example, iso-displacement curves 79, 80, 81 are isochronous curves as defined above. Each time increment is for example between 1 minute and 1 hour, in particular between 2 minutes and 10 minutes, for example 5 minutes. Each time interval between two extended iso-displacement curves 83 is then advantageously defined by at least 3 time increments, in particular by between 4 and 20 time increments.

[0163] As specified above, the optimal trajectory 64A is obtained at each iteration in a manner not constrained by the network of waypoints 53A and / or trajectories 53B imposed between the waypoints 53A.

[0164] Then at each iteration, as illustrated in the figure 13 , the definition module 63 advantageously defines the optimization region 63A of the trajectory around the optimal trajectory 64A as a function of a predetermined lateral distance at each point of the optimal trajectory 64A defined by the first calculation module 64 and as a function of the operational mission specifications, in particular the mission context, in particular navigation constraints, meteorological constraints, and passenger comfort constraints.

[0165] Advantageously, the definition module 63 laterally delimits the optimization region 63A of the trajectory 64A by lateral limits extending laterally at a distance chosen as a function of the density of the aerial network of each point of the optimal trajectory 64A.

[0166] Thus, the optimization region 63A is generally defined by a band encompassing the trajectory 64A. As indicated previously, the band is also potentially constrained by the prohibited flight zones 24, by the zones 28 of dangerous meteorological phenomena and / or by the turbulence zones 30. It encompasses, as the case may be, the satellite coverage zones 32.

[0167] Then, as illustrated by the figure 10 , the definition application 92 loads the coordinates of waypoints 53A and trajectories 53B imposed between the waypoints 53A from the database 52, within the optimization region 63A.

[0168] The definition application 92 defines, among the waypoints 53A, the nodes 96 which are the possible waypoints 53A for the aircraft, taking into account in particular the mission constraints, in particular the navigation constraints, the meteorological constraints, and the passenger comfort constraints.

[0169] The definition application 93 further defines the cost associated with the passage between two adjacent nodes 96 based on the geographical distance separating the two nodes 96, and also on the meteorological context retrieved from the module 60, and possibly on the aircraft context, for example the type and age of the engines, retrieved from the initialization module 58.

[0170] The application 98 for determining the optimized trajectory 65A then implements a cost minimization algorithm to define the least costly trajectory passing through the nodes 96 and through the trajectories imposed between the nodes 96, from the geographical point of origin 18 to the geographical point of destination 20. This algorithm is for example by a Dijkstra algorithm. An optimized trajectory 65A is then obtained by minimizing the cost, as described in patent application No. 1800734.

[0171] The optimized trajectory 65A obtained at each iteration is constrained by a network of waypoints 53A and imposed trajectories 53B between the waypoints 53A in the aerial network.

[0172] The calculation engine 40 then calculates all of the mission parameters on the basis of the optimized trajectory 65A obtained at the current iteration, and determines the difference between the mission parameter to be optimized (for example the takeoff weight) for the initial trajectory and the mission parameter to be optimized for the optimized trajectory 65A.

[0173] The calculation engine then performs new calculations of trajectories 64A, 65A, as described previously, using the iso-displacement curves, until the mission parameter, here the takeoff mass, converges towards a desired mission parameter value.

[0174] Convergence is for example determined when the difference between the value of the mission parameter for the trajectory determined at the previous iteration and that determined at the current iteration is less than a predetermined value.

[0175] In particular, in the case of takeoff weight, the difference between the takeoff weight for the trajectory determined in the previous iteration and that determined in the current iteration must be less than a predetermined weight, for example equal to 100 pounds.

[0176] Alternatively, the mission parameter is the landing mass or the distance traveled along the trajectory.

[0177] Advantageously, after convergence, the mission engine 40 verifies the consistency of the high-speed performance using the application 66.

[0178] The mission engine 40 verifies in particular that the takeoff mass obtained using the calculation modules 64, 65 after convergence is less than or equal to the maximum mass allowing the aircraft to take off obtained using the low speed application 70 to ensure that the aircraft will be able to take off on the terrain chosen for takeoff.

[0179] More generally, the low speed performance determination software application 70 is implemented to verify that the mission parameters obtained are compatible with the terrain on which the aircraft is intended to take off and / or land.

[0180] The calculation engine 40 then establishes a data file comprising a list of waypoints 53A, and a list of trajectories 53B between the waypoints 53A.

[0181] As indicated above, the data file provided by the second calculation module 65 further advantageously comprises a list of headings TCA between the waypoints 53A, a list of distances DST between the waypoints 53A, a list of wind components COMP between the waypoints 53A, a list of true speeds TAS between the waypoints 53A, a list of ground speeds GS between the waypoints 53A, a list of static air temperatures SAT between the waypoints 53A, a list of turbulence levels SHR between the waypoints 53A, a list of estimated arrival times ETA at a waypoint 53A, and a list of estimated en route times EET.

[0182] In the variant illustrated by the figure 14 , the calculation system 10 is integrated within an electronic flight baggage (“Electronic Flight Bag” or “EFB” in English), or a portable electronic device 100.

[0183] The portable electronic device 100 is for example connected to the databases 50, 52 by a wireless data link following a wireless transmission protocol for example of the Wifi type (for example following the IEEE 802.11 Standard), or Bluetooth (for example following the IEEE 802.15-1-2005 Standard).

[0184] In another variant, each iso-displacement curve calculated by the calculation module 64 is an iso-fuel consumption curve.

[0185] The first calculation module 64 is capable, from any chosen point 78 accessible to the aircraft, of establishing a plurality of fuel iso-consumption curves, corresponding to levels at distinct flight levels, on a predetermined increment of fuel consumed from the chosen point 78, then of determining an extended fuel iso-consumption curve from the plurality of fuel iso-consumption curves.

[0186] By definition, a fuel iso-consumption curve is a curve connecting the points accessible to the aircraft from a given point 82 with a given fuel consumption which corresponds to one or more increments of fuel consumed. Each increment of fuel consumed is chosen at a constant value, for example between 22.7 kg (50 lbs) and 453.6 kg (1000 lbs), in particular between 36.3 kg (80 lbs) and 54.4 kg (120 lbs).

[0187] In this example, each fuel iso-consumption curve is determined from a chosen point 78 by calculating from the chosen point all the points accessible to the aircraft, at a given air speed, taking into account the meteorological context, in particular the direction and intensity of the wind, as provided by the recovery module 60 and the aircraft performance, as determined by the determination module 62.

[0188] As previously, the first calculation module 64 is capable of selectively excluding points which are located in prohibited flight zones or levels 24, in zones 28 of dangerous meteorological phenomena and / or in turbulence zones 30. On the contrary, the first calculation module 64 is capable of also excluding points which would not be located in a satellite coverage zone 32.

[0189] The first calculation module 64 is then capable of defining an optimal trajectory 64A by choosing successive points of the optimal trajectory 64A on successive extended fuel iso-consumption curves.

[0190] In another variant, the iso-travel curves are iso-cost curves, with cost defined as a function of travel time and fuel consumed, for example as a ratio of travel time and fuel consumed.

[0191] Each increment of movement is a cost increment of a given constant value.

[0192] Each iso-cost curve is determined from a chosen point 78 by calculating from the chosen point all the points accessible to the aircraft, at a given air speed, taking into account the meteorological context, in particular the direction and intensity of the wind, as provided by the recovery module 60 and the aircraft performance, as determined by the calculation functions of the application 68.

[0193] As previously, the first calculation module 64 is capable of selectively excluding points which are located in prohibited flight zones or levels 24, in zones 28 of dangerous meteorological phenomena and / or in turbulence zones 30. On the contrary, the first calculation module 64 is capable of also excluding points which would not be located in a satellite coverage zone 32.

[0194] The first calculation module 64 is then capable of defining an optimal trajectory 64A by choosing successive points of the optimal trajectory 64A on successive extended iso-cost curves.

[0195] In yet another variant of all the embodiments previously described, the iso-displacement curves are not determined at a given air speed, but according to a determined air speed profile, for example as a function of altitude or even at maximum thrust.

Claims

1. An aircraft mission calculating system (10) including a calculation engine (40) for calculating aircraft trajectories during the mission, the calculation engine (40) comprising: - a first path calculation module (64), capable of calculating an optimal mission path (64A) between a geographical point of origin (18) and a geographical destination point (20), as a function of airplane performance, operational mission specifications and a weather context, preferably evolving, in a mission volume between the geographical point of origin (18) and the geographical destination point (20), the first path calculation module (64) being able to calculate a plurality of iso-movement curves (79, 80, 81) from at least one selected point (78) accessible to the aircraft, at a movement range corresponding to several successive movement increments of the aircraft from the selected point (78), each iso-movement curve (79, 80, 81) being an isochronous curve connecting the accessible points for the aircraft from a given point in a given time which corresponds to one or more time increments, the first path calculation module (64) being able to calculate a path minimizing the time between the geographical point of origin (18) and the geographical destination point (20), or wherein each iso-movement curve (79, 80, 81) is a fuel iso-consumption curve connecting the accessible points for the aircraft with a given point with a given fuel consumption which corresponds to one or more fuel consumption increments, the first path calculation module (64) being able to calculate a path minimizing the consumption of fuel between the geographical point of origin (18) and the geographical destination point (20), or wherein each iso-movement curve (79, 80, 81) is an iso-cost curve, the cost being defined as a function of the travel time and the consumed fuel, each movement increment being a cost increment with a constant given value, the first path calculation module (64) being able to calculate a path minimizing the cost between the geographical point of origin (18) and the geographical destination point (20), characterized in that the iso-movement curves (79, 80, 81) are obtained at the movement range for a movement of the aircraft to a given flight level from movements of the aircraft at separate flight altitude levels, and that the first path calculation module (64) is able to determine, based on iso-movement curves (79, 80, 81) up to the given flight level, obtained at separate flight levels, taken at the same movement range of the aircraft, at least one extended iso-movement curve (83) at the given flight level maximizing the movement of the aircraft from the geographical point of origin (18) or minimizing the movement of the aircraft toward the geographical destination point (20), the first path calculation module (64) being able to define a path from a plurality of path segments (88A to 88D), each path segment (88A to 88D) being defined at a given flight level on a plurality of iso-movement curves (79, 80, 81) of the flight altitude level corresponding to the given flight level from an extended iso-movement curve (83) and / or toward an extended iso-movement curve (83), wherein the extended iso-movement curve (83) is calculated as the location of the points of the plurality of iso-movement curves (79, 80, 81) up to the given flight level, for which the movement of the aircraft from the geographical point of origin (18) is maximized or for which the movement of the aircraft toward the geographical destination point (20) is minimized, each point of the extended iso-movement curve (83) being a point of a specific iso-movement curve up to the given altitude flight level chosen among the plurality of iso-movement curves (79, 80, 81) obtained for a movement of the aircraft up to the given flight level from movements of the aircraft at separate altitude flight levels.

2. The system (10) according to claim 1, wherein an iso-movement curve (79) up to the given flight altitude level corresponds to an altitude level movement at the given flight level, at least one iso-movement curve (80, 81) up to the given flight level corresponding to a movement of the aircraft at an flight altitude level separate from the given flight level, the or each iso-movement curve (80, 81) up to the given flight level corresponding to a movement of the aircraft at an altitude flight level separate from the given flight level being obtained with a movement of the aircraft including an altitude level flight phase (84) at the flight level separate from the given flight level and a phase (85) for reaching the given flight level from the level flight phase (84).

3. The system (10) according to claim 2, wherein the phase (85) for reaching the given flight level comprises an ascent or a descent according to a predetermined profile, advantageously with a constant slope, constant Mach or constant true airspeed.

4. The system (10) according to claim 2 or 3, wherein the calculation of the iso-movement curve (79, 80, 81) up to the given flight altitude level corresponding to a movement of the aircraft at a flight altitude level separate from the given flight level comprises calculating an intermediate movement increment at which the phase (85) for reaching the flight level begins, determining an intermediate iso-movement curve at the separate flight altitude level at the intermediate movement increment, then determining the iso-movement curve (79, 80, 81) up to the given flight level from the intermediate iso-movement curve.

5. The system (10) according to any one of the preceding claims, wherein the selected point (78) is the geographical point of origin (18) or an end point of the ascent from the geographical point of origin (18) or wherein the selected point (78) is the geographical destination point (20) or a starting point of the descent toward the geographical destination point (20).

6. The system (10) according to any one of the preceding claims, wherein the chosen point (78) is a point on a previously determined extended iso-movement curve (83).

7. The system (10) according to any one of the preceding claims, wherein the first path calculation module (64) is able to determine a plurality of successive iso-movement curves (79, 80, 81) at each movement increment, at least one extended iso-movement curve (83) being obtained from another extended iso-movement curve (83) by calculating a plurality of iso-movement curves (79, 80, 81) from the other extended iso-movement curve (83), for a movement range corresponding to several movement increments of the aircraft, each iso-movement curve (79, 80, 81) being obtained for a movement of the aircraft at a separate flight altitude level toward a given flight level.

8. The system (10) according to any of the preceding claims, wherein the first path calculation module (64) is able to determine, after each movement range corresponding to several movement increments, a plurality of extended iso-movement curves (83) at separate flight levels, at least one path segment (88B) being defined between a first point (87A) of a first extended iso-movement curve (83) determined at a first flight level and a second point (87B) of a second extended iso-movement curve (83) determined at a second flight level different from the first flight level, the first point (87A) corresponding to a point of an iso-movement curve (80) resulting from an altitude level flight phase (84) at the second flight level and a phase (85) for reaching the first flight level from the altitude level flight phase at the second flight level.

9. The system (10) according to claim 8, wherein the first path calculation module (64) is able first to determine a downstream path segment (88A) before the geographical destination point (20) or a beginning of descent point toward the geographical destination point (20) and the extended iso-movement curve (83) corresponding to the last movement range made up of several iso-movement increments toward the geographical destination point (20) or toward the geographical beginning of descent point toward the geographical destination point (20), the first path calculation module (64) being advantageously able to determine at least one intermediate path segment (88B, 88C) between at least two extended iso-movement curves (83) on either side of a movement range made up of several iso-movement increments, the first path calculation module (64) being then able to determine at least one upstream path segment between an extended iso-movement curve (83) corresponding to a movement range made up of several iso-movement increments from the geographical point of origin (18) or from an end of ascent point from the geographical point of origin (18).

10. The system (10) according to any one of the preceding claims, wherein the mission context includes navigation constraints comprising at least one three-dimensional or four dimensional avoidance zone or three-dimensional or four-dimensional desired passage zone, the extended iso-movement curve (83) being calculated from chosen iso-movement curves (79, 80, 81) for movements at flight altitude levels avoiding the three-dimensional or four-dimensional avoidance zone and / or passing through the three-dimensional or four-dimensional desired passage zone.

11. A process for calculating a mission of an aircraft, using a mission calculating system (10) including a calculation engine (40) for calculating paths of the aircraft during the mission, the method including the following steps: - calculating, via a first path calculation module (64) of the calculation engine (40), an optimal mission path (64A) between a geographical point of origin (18) and a geographical destination point (20), as a function of airplane performance, operational mission specifications and a weather context, preferably evolving, in a mission volume between the geographical point of origin (18) and the geographical destination point (20), in which, during the calculating step, the first path calculation module (64) calculates a plurality of iso-movement curves (79, 80, 81) from at least one selected point (78) accessible to the aircraft, at a movement range corresponding to several successive movement increments of the aircraft from the selected point (78), wherein each iso-movement curve (79, 80, 81) is a isochronous curve connecting the accessible points for the aircraft from a given point in a given time which corresponds to one or more time increments, the first path calculation module (64) being able to calculate a path minimizing the time between the geographical point of origin (18) and the geographical destination point (20), or wherein each iso-movement curve (79, 80, 81) is a fuel iso-consumption curve connecting the accessible points for the aircraft with a given point with a given fuel consumption which corresponds to one or more fuel consumption increments, the first path calculation module (64) being able to calculate a path minimizing the consumption of fuel between the geographical point of origin (18) and the geographical destination point (20), or wherein each iso-movement curve (79, 80, 81) is an iso-cost curve, the cost being defined as a function of the travel time and the consumed fuel, each movement increment being a cost increment with a constant given value, the first path calculation module (64) being able to calculate a path minimizing the cost between the geographical point of origin (18) and the geographical destination point (20), characterized in that: the iso-movement curves (79, 80, 81) are obtained at the movement range for a movement of the aircraft to a given flight level from movements of the aircraft at separate flight altitude levels, and the first path calculation module (64) determines, based on iso-movement curves (79, 80, 81) up to the given flight level, obtained at separate flight altitude levels, taken at the same movement range of the aircraft, at least one extended iso-movement curve (83) at the given flight level maximizing the movement of the aircraft from the geographical point of origin (18) or minimizing the movement of the aircraft toward the geographical destination point (20), the first path calculation module (64) defining a path from a plurality of path segments (88A to 88D), each path segment (88A to 88D) being defined at a given flight level on a plurality of iso-movement curves (79, 80, 81) of the flight altitude level corresponding to the given flight level from an extended iso-movement curve (83) and / or toward an extended iso-movement curve (83), wherein the extended iso-movement curve (83) is calculated as the location of the points of the plurality of iso-movement curves (79, 80, 81) up to the given flight level, for which the movement of the aircraft from the geographical point of origin (18) is maximized or for which the movement of the aircraft toward the geographical destination point (20) is minimized, each point of the extended iso-movement curve (83) being a point of a specific iso-movement curve up to the given flight level chosen among the plurality of iso-movement curves (79, 80, 81) obtained for a movement of the aircraft up to the given flight level from movements of the aircraft at separate flight altitude levels.