EP4270363A1 - Method and system for operating an aircraft - Google Patents

Abstract

A method for operating an aircraft (1) is proposed, in which a volume enveloping the trajectory (NT) is determined for a predetermined trajectory (NT) of the aircraft (1), which volume is a first, inner volume and a second, outer volume comprises, wherein the second volume surrounds the first volume, the first volume being composed of a plurality of first individual volumes (TVi) and the second volume being composed of a number of second individual volumes, which individual volumes (TVi) at each point of the trajectory (NT). are calculated based on parameters (v_i) of an actual flight status of the aircraft (1) at a respective point in time.

Description

The invention relates to a method for operating an aircraft according to claim 1, a system for operating an aircraft according to claim 11 and a correspondingly equipped aircraft according to claim 13.

In Europe, for the operation of aircraft, especially so-called UAVs ("unmanned aerial vehicles"), limits of the airspace approved for a mission are defined using quantitative calculation methods. These methods use purely static, i.e. fixed volumes that are calculated based on conservative assumptions. The entire mission scope must remain within predetermined volumes, even if the mission gets out of control.

For a flight controlled by a human pilot, so-called "tunnels in the sky" can be used to make it easier for the human pilot to follow a predefined trajectory or flight path, e.g. for precision approaches. These “tunnels in the sky” are shown to the pilot via a suitable display together with a relative position of the aircraft in relation to a reference trajectory.

Classic "geocaging" involves limiting flight operations to an approved geographical "volume", ie a specific (airspace) area, the so-called "geocage"; The operation of a UAV is therefore limited to missions within this area. A specific trajectory that is flown within the flight area is only taken into account if there is a risk of violating the external boundaries of the area. However, for missions in complex environments (e.g. cities, mountains, archipelago areas, etc.) or in controlled airspace, it is often practically impossible to define larger, contiguous operating areas within which a UAV can be located can move freely. Instead, a pre-approved flight path (target path) must be flown as precisely as possible or any deviations from the planned flight path must be responded to as early as possible. Deviations from the target trajectory that are larger than expected can then mean that certain sections of a trajectory can no longer be flown or that certain take-off/landing areas (so-called vertiports) can no longer be approached.

There is therefore a need to specify a method and a system for operating an aircraft with which the freest possible flight movement can be achieved, especially of UAVs, but also of manned aircraft, even in difficult or complex flight environments.

The invention solves this problem by means of a method according to claim 1, a system according to claim 11 and an aircraft according to claim 13.

Advantageous further training is defined in the subclaims.

According to the invention, a method for operating an aircraft provides that a volume enveloping the trajectory is determined for a predetermined trajectory or flight path of the aircraft, which volume comprises a first, inner volume and a second, outer volume, the second volume surrounding the first volume , preferably in every imaginary plane of the 3D space perpendicular to the trajectory, the first volume being composed of a plurality of first individual volumes and the second volume being composed of a number of second individual volumes, which individual volumes at each point of the trajectory based on Parameters of an actual flight status of the aircraft can be calculated at a particular point in time.

In this way, it is possible to define metrics for the quality of the path sequence, to implement them based on flight physics parameters and to monitor them continuously, so that the freest possible flight movement can be achieved even in difficult or complex flight environments. This possibility exists regardless of whether the aircraft is operated manned or unmanned.

According to the second aspect of the invention, this creates a system for operating an aircraft with a geocaging module, which according to the invention functions as a volume determination module that is located on board the aircraft or on the ground, the volume determination module in the second case being connected to the aircraft via a data link is which volume determination module is designed and intended to determine the volumes required to carry out the method according to the invention on the basis of a nominal trajectory, i.e. a pre-planned trajectory, and which for this purpose contains at least a current position, a current speed and a current heading as input data, i.e. the direction of flight of the aircraft.

An aircraft according to the invention is characterized in that it is equipped with a system according to the invention for operating the aircraft.

For each trajectory, a geocage is calculated in the form of the above-mentioned volume, which geocage is calculated from a so-called flight geography (first volume) and a so-called contingency volume (second volume), and which geocage is based on a respective nominal flight condition along the named trajectory. For trajectories planned online, the geocage is preferably calculated at the time of flight; in the case of trajectories planned before departure, the geocage can also be calculated before the mission starts.

The geocage includes first partial or individual volumes, which describe the nominal trajectory tracking quality of the aircraft, as well as second partial volumes, within which partial volumes so-called remedial or contingency measures can or must be carried out in order to determine a current flight path of the aircraft in the direction back to the to correct the planned trajectory.

The calculation of the volumes mentioned is based on parameters of the actual flight condition, such as preferably a (planned) speed, flight altitude, trajectory angle or other factors (e.g. weather conditions).

In a further embodiment of the invention, the direction of flight of the UAV can also be taken into account. This means that volumes are no longer scaled in an undirected manner. Boundaries of the geocage that are in the direction of flight can therefore be classified as more critical than boundaries that are, for example, parallel or opposite to the direction of flight. In this way an expansion of Flight Geography and contingency volumes must be larger in the direction of flight than against the direction of flight or in the sideways direction.

During the flight, it is preferably checked whether the aircraft is still within the geocage around the nominal or reference trajectory. If the aircraft leaves the Flight Geography (first volume), priority countermeasures are initiated to save the mission. However, if the aircraft leaves the contingency volume (second volume), the mission is preferably aborted and immediate measures, such as an immediate safety landing, are most preferably initiated in order to protect people and/or material.

A preferred distinction is made between two forms of operation: In a manned operation, flight geography and contingency volume are displayed to the pilot in a pilot display (e.g. a head-up display (HUD)) as an extension of a "tunnel-in-the-sky". If the flight geography is violated, for example, the pilot is asked (visually and/or acoustically) to return to the actual trajectory; In addition, the USSP (U-Space Service Provider) is preferably informed. If the contingency volume is violated, an immediate safety landing is preferably required. In this context, this means that the mission is aborted and a landing is carried out at the nearest alternative landing site. The priority of the aircraft can also be increased for so-called deconflicting measures (similar to, for example, a radio failure on the landing approach in order to avoid and resolve conflicts between the flight paths of several air traffic participants).

If, on the other hand, there is an unmanned operation and the aircraft is flying within the contingency volume, so-called recovery maneuvers (which lead the aircraft back to flight geography) can be triggered automatically or control can be taken over by a remote pilot, for example sitting at a flight control center. be requested. The operator and air traffic control are preferably additionally informed. Further measures or the remote pilot taking over control (if not already done, see above) are initiated when the contingency volume is exceeded.

Potentially, additionally or alternatively, a change in the control strategy (e.g. a fallback to a more robust and/or low-performance controller) can also be possible. or an alternative to routes with lower demands on navigation performance should be made so that the aircraft can continue its mission as far as possible.

The implementation of the volumes mentioned enables continuous and traceable monitoring of the tracking performance, which can also be visually displayed to a pilot. The tracking performance or path following performance describes how precisely the aircraft can follow a given path. This is usually determined by the navigation error (i.e. the inaccuracy in determining one's own position) and the flight technology error (i.e. the inaccuracy with which a controller or pilot follows a target trajectory). This trajectory performance must be monitored to determine whether it is within an expected range of values or whether countermeasures need to be taken.

Furthermore, flight corridors result within which an aircraft is actually very likely to be during nominal operation, in contrast to conservatively estimated areas that are largely of no practical relevance. This information can be used in particular to plan multiple routes in the same airspace and to optimize airspace utilization.

This can be implemented using a so-called geocaging module, which can be implemented both on board the aircraft and as part of a ground control station. In the latter case, communication with the aircraft preferably takes place via a critical data link.

Special, advantageous embodiments of the invention are explicitly pointed out below:
A further development of the method according to the invention provides that the parameters include at least one of the following influencing variables: planned speed of the aircraft, flight altitude, trajectory angle, weather conditions, in particular wind strength and wind direction, worst-case behavior of the aircraft in the event of loss of control and feasibility of a recovery maneuver respective point in time. This means that the (individual) volumes mentioned can be adapted as best as possible to a given situation and do not have to be made excessively large using conservative estimates.

The planned speed is preferably taken into account when calculating the volumes to be monitored. The current speed, on the other hand, is used to subsequently monitor the volumes calculated based on the target trajectory.

The aforementioned trajectory angle (also climbing angle) describes the angle of the flight path relative to a tangential plane, which is spanned at the perpendicular point of the flight path on the earth's reference ellipsoid. The trajectory angle therefore describes how steeply the aircraft climbs or descends.

Another development of the method according to the invention provides that the individual volumes are calculated taking into account a direction of flight of the aircraft. In this way, the volumes do not have to be scaled in an undirected manner, as was already pointed out in detail above.

In order to enable path planning to be as flexible as possible, another development of the method according to the invention provides that the individual volumes are calculated based on the flight time.

Alternatively, however, an embodiment is also possible in which the individual volumes are calculated before the start of a mission of the aircraft. In this way, the requirements for hardware on board the aircraft can be reduced in particular.

In order to be able to react as quickly as possible to external circumstances, another development of the method according to the invention provides that during a flight it is continuously checked whether the aircraft is within the volume, in particular within the first volume.

Advantageously, with a corresponding development of the method according to the invention, it is provided that recovery maneuvers are initiated when the aircraft detects that the first volume has left; and/or that if the aircraft is detected to be leaving the second volume, a current mission will be aborted and immediate measures, such as an immediate safety landing, will be initiated. In this way, catastrophic events can be avoided and people and materials can be protected.

It has already been pointed out that two possible cases are distinguished within the scope of the method according to the invention: in the case of manned operation of the aircraft, the first volume and the second volume can be graphically displayed to a pilot on board the aircraft in a display, in particular in a head -up display, preferably when the aircraft leaves the first volume, the pilot is optically (visually) and / or acoustically requested to return to the (nominal) trajectory, and most preferably a responsible U-space service provider is informed.

On the other hand, in the case of unmanned operation of the aircraft when it leaves the first volume, recovery maneuvers can be triggered automatically and/or a remote pilot can request that control of the aircraft be taken over, with an operator of the aircraft and a responsible airspace surveillance preferably also being automatically informed. Furthermore, most preferably when leaving the second volume, further measures or the remote pilot taking over control, if not already done, can be initiated. This has already been pointed out above.

With appropriate development of the method according to the invention, an additional or alternative measure exists in the form of a change in a control strategy of the aircraft, in particular a switch to a more robust, low-performance controller, and / or a switch to a trajectory with lower demands on the navigation performance of the aircraft. This has also already been pointed out above.

In a further development of the system according to the invention, it can also be provided that the volume determination module is designed to compare a respective geometry of the specific volumes with received navigation data of the aircraft and to command remedial measures specifically in the event of a violation of the first volume, i.e. to issue corresponding control commands.

• Figur 1 zeigt ein Fluggerät mitsamt Nominaltrajektorie und mehreren ersten Einzelvolumina;
• Figur 2 zeigt eine Flugbahn mitsamt den sie einhüllenden ersten und zweiten Volumina;
• Figur 3 zeigt verschiedene Möglichkeiten der Skalierung eines Geocage; und
• Figur 4 zeigt eine mögliche konstruktive Ausgestaltung des erfindungsgemäßen Systems.

Further properties and advantages of the invention result from the following description of exemplary embodiments based on the drawing.

• Figure 1 shows an aircraft including the nominal trajectory and several initial individual volumes;
• Figure 2 shows a trajectory including the first and second volumes that envelop it;
• Figure 3 shows different ways to scale a geocage; and
• Figure 4 shows a possible structural design of the system according to the invention.

In Figure 1 an (unmanned) aircraft 1 (UAV) is shown, which aircraft 1 moves along a (nominal) trajectory NT. Certain points are marked along the trajectory NT, and in each of these points an instantaneous speed of the aircraft 1 along the trajectory NT is indicated vectorially ( ν _i , i = 1... n ). The speed represents a possible physical influencing variable or a possible parameter of an actual flight status of the aircraft 1 at a respective point in time, which is taken into account in the context of the method according to the invention.

Volumes are defined for the trajectory NT, which indicate the path deviation of the aircraft 1 expected during nominal operation, ie its deviation from the trajectory NT. These (individual) volumes are in Figure 1 for each of the specified times indicated by a corresponding ellipse TVi . Together, the volumes TVi mentioned result in a first volume which envelops the trajectories NT and is also referred to in the present case as “flight geography”. In addition, a so-called contingency volume (second volume) is defined, which surrounds the first volume (in Figure 1 Not shown; see. Figure 2 ). The contingency volume refers to an area within which the aircraft 1 can be brought under control and/or back to the planned trajectory NT. According to the invention, the calculation of these volumes is made dependent on the actual flight status of the aircraft 1 and other influencing factors, which were pointed out in detail above. In the Figure 1 The specified speed represents only a special example of such an influencing factor.

For each actual state of the aircraft 1 along the planned trajectory NT, the geocage is derived using analytical models. As already mentioned, these models preferably take into account, among other things, the current speed of the aircraft 1, ν _i , an assumed worst-case behavior of the aircraft 1 in the event of loss of control and the feasibility of a recovery maneuver at the respective time. During the flight, it is preferably continuously checked whether the position of the aircraft 1 violates these limits, i.e. the limitations of the geocage.

In Figure 2 A resulting complete Geocage GC is shown in a simplified representation, which consists of a first volume enveloping the trajectory NT ("Flight Geography"; compare Figure 1 ) V1 and a second volume (“Contingency Volume”) V2 surrounding the first volume V1. The flight geography (volume V1) of a trajectory NT is the envelope of the flight geography determined at each state point, in particular with speed ν _i (compare the individual volumes TVi in Figure 1 ) calculated. The calculation of the contingency volume (volume V2) is carried out analogously from corresponding individual volumes and leads to the in Figure 2 Trajectory NT shown in simplified form, which trajectory NT is surrounded by the respective flight areas (volumes V1, V2).

Although this is in Figure 2 For the sake of simplicity, the calculation of the geocage GT can preferably also be carried out in three dimensions, so that a "tunnel" is created around the nominal trajectory NT, within which the aircraft 1 must remain.

Figure 3 , left, shows a direction-independent implementation of range scaling for the first volume (V1, inside) and the second volume (V2, outside) with unidirectional weighting heuristic Γ . Such a configuration is particularly suitable for small instantaneous speeds ν of the aircraft (not shown). An expansion of the first volume or the second volume does not depend on an angle ΔΨ based on a current flight direction of the aircraft.

The right side of the Figure 3 shows an embodiment with direction-weighted geocage zones (first volume V1 or second volume V2) and corresponding weighting heuristic Γ . An expansion of the volumes mentioned is clear larger for small angles ΔΨ based on a current flight direction of the aircraft than for large angles ΔΨ. Such a configuration is particularly suitable for larger instantaneous speeds ν of the aircraft (not shown).

While the first version also takes into account scaling of the geocage in directions that are not relevant from a physical point of view or only have a very low probability of becoming relevant, a second version of the system takes the direction of flight into account when evaluating the permissible flight areas. The approach is based on the assumption that the probability of a deviation from the nominal trajectory in a certain direction decreases as the angular difference ΔΨ to the current flight direction (corresponding to the vector ν ) increases.

The method described can be implemented using a suitably designed geocaging module, as exemplified in Figure 4 is shown. The geocaging module (GCM) 2 interacts in terms of signaling with a navigation system 3 for the aircraft (in Figure 4 Not shown); The geocaging module 2 preferably receives the current position, the current speed and a current heading of the aircraft as input data ID from the navigation system 3. Within the geocaging module 2, the geometry of the geocage is calculated based on the nominal trajectory (which is assumed to be known) (see above Figures 1 to 3 ) and compared with the received navigation data. The geocaging module 2 thus functions in particular as a volume determination module, which is designed and intended to determine the volumes required to carry out the method according to the invention on the basis of the nominal trajectory, and for this purpose preferably receives at least the above-mentioned input data. If a flight area is violated (the aircraft leaves the relevant area boundaries), the GCM 2 in particular commands appropriate contingency measures or initiates a mission abort.

Depending on the respective operating mode (named/unmanned), the invention closes accordingly Figure 4 the display of the geocage on a pilot display or a function for carrying out recovery maneuvers in the flight guidance system. For this purpose, for example, in step 4 a query is made as to whether the unmanned operating mode is active. If this query is answered in the affirmative (j), the reference symbol 5 the mentioned function for carrying out recovery maneuvers in the flight guidance system is activated. Otherwise (n), the geocage is shown at reference number 6 on the pilot display, for example a head-up display (HUD).

The geocaging module 2 does not have to be installed on board an aircraft, but can also be part of a ground station that communicates with an aircraft via a corresponding connection.

Claims (13)

Method for operating an aircraft (1), in which a volume enveloping the trajectory (NT) is determined for a predetermined trajectory (NT) of the aircraft (1), which volume is a first, inner volume (V1) and a second, outer volume (V2), wherein the second volume (V2) surrounds the first volume (V1), wherein the first volume (V1) consists of a plurality of first individual volumes (TVi) and the second volume (V2) consists of a number of second individual volumes which individual volumes (TVi) are calculated at each point of the trajectory (NT) based on parameters (ν _i ) of an actual flight status of the aircraft (1) at a respective point in time. Method according to claim 1, in which the parameters include at least one of the following influencing variables: planned speed (ν) of the aircraft (1), flight altitude, trajectory angle, weather conditions, in particular wind strength and wind direction, worst-case behavior of the aircraft (1) in the event of loss of control and feasibility of a recovery maneuver at the given time. Method according to claim 1 or 2, in which the individual volumes (TVi) are calculated taking into account a direction of flight of the aircraft (1). Method according to one of claims 1 to 3, in which the individual volumes (TVi) are calculated at the time of flight. Method according to one of claims 1 to 3, in which the individual volumes (TVi) are calculated before the start of a mission of the aircraft (1). Method according to one of claims 1 to 5, in which it is continuously checked during a flight whether the aircraft (1) is within the volume, in particular within the first volume (V1). Method according to one of claims 1 to 6, in which recovery maneuvers are initiated when the aircraft (1) detects that the first volume (V1) has left; and or
in which, if the aircraft (1) is detected leaving the second volume (V2), a current mission is aborted and immediate measures, such as an immediate safety landing, are initiated. Method according to one of claims 1 to 7, in which, in the case of manned operation of the aircraft (1), the first volume (V1) and the second volume (V2) are graphically displayed in a display to a pilot on board the aircraft (1), in particular in a head-up display, preferably when the aircraft (1) leaves the first volume (V1), the pilot is visually and/or acoustically requested to return to the trajectory (NT), and most preferably a responsible U- Space service provider is informed. Method according to one of claims 1 to 8, in which, in the event of unmanned operation of the aircraft (1), when the first volume (V1) leaves the first volume (V1), automated recovery maneuvers are triggered and/or control of the aircraft (1) is taken over by a remote pilot is requested, preferably in addition an operator of the aircraft (1) and a responsible airspace surveillance are automatically informed and most preferably when leaving the second volume (V2) further measures or the assumption of control by the remote pilot, if not already done, are initiated. Method according to one of claims 1 to 9, in which a change in a control strategy of the aircraft (1), in particular a switch to a more robust, low-performance controller, and / or a switch to a trajectory (NT) with lower demands on the navigation performance of the aircraft (1), takes place. System for operating an aircraft (1) with a volume determination module (2) which is located on board the aircraft (1) or on the ground, wherein in the second case the volume determination module (2) is connected to the aircraft (1) via a data link, which volume determination module (2) is designed and intended to measure the volumes required to carry out the method according to one of the preceding claims (V1, V2) on the basis of a nominal trajectory (NT), and for this purpose receives as input data (ID) at least a current position, a current speed (ν _i , ν) and a current heading of the aircraft (1). System according to claim 11, in which the volume determination module (2) is designed to compare a respective geometry of the specific volumes (V1, V2) with received navigation data of the aircraft (1) and in particular when the first volume (V1) is violated and / or to command remedial action in the event of a violation of the second volume (V2). Aircraft (1) with a system according to claim 11 or 12.

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