Patent Grant
8527190
The present invention relates to a method and a system for aiding the taxiing of an aircraft on an airport domain such as an aerodrome or an airport.
The present invention applies to the taxiing of an aircraft such as, particularly, a civil or military airplane, transporting passengers or goods (freight), or a drone (pilotless aircraft). More particularly, it relates to the generation of a trajectory on the ground, which is such that the aircraft can be manually or automatically guided along this trajectory on the airport domain. Furthermore, the method and system for aiding the piloting include, respectively, a method and a device generating such a trajectory.
Within the scope of the present invention, it is meant:
The path to be followed on the ground is generally given to the pilot, for instance through radio-communication means or through other ordinary means such as a digital data transmission link, by an air traffic controller or a ground controller, but it can also, in some cases, be freely chosen by the pilot.
The path is defined as an element succession on the airport domain, and indicates a way for reaching, from a point or region of the airport domain, another point or region of said domain.
Within the scope of the present invention, it is called by airport domain, any portion of the domain, referred or not as a designation, and identified as a distinct and bounded part of the domain. By element, it is particularly referred to a part or all the surfaces bounding the takeoff and landing runways, the runways, the guiding ways, the taxiway sections, the turn-around areas, the waiting zones, the stop bars, the stand positions, the maneuvering areas and the parking areas.
Within the present invention, furthermore, it is referred as:
Furthermore, it is known that airport navigation systems mounted on-board airplanes enables to visualize the airport geometry, and for some of them (such as an OANS (“On board Airport Navigation System”) type system, so as to show the current position of the airplane on the airport map displayed on the piloting station. The airport map can be shown on navigation screens or on those of the world being opened according to the applications.
The airport maps are generated from on-board current databases. These databases are formed ordinarily from air images of the airport which are discriminated in different elements (runways, sections of taxiways, guiding lines, . . . ), each element being defined by a set of points and different attributes enabling the on-board system to draw the airport geometry as it is shown on paper maps (Jeppesen type) or scanned in the systems of the EFB (“Electronic Flight Bag”) type.
The on-board system will shall have to make do with reading databases, interpreting the information defining the different constitutive elements of the airport, and displaying them by connecting the points by straight lines so as to graphically give back either the surfaces or the guiding lines painted on these elements.
The format definition of these on-board databases has been normalized (standard ED-99B). This definition covers all the map displaying cases, but has not been planned to display trajectories. In particular, the geometry of each element of the airport is precisely and completely described therein, but there is no link between the different elements, so that it is not possible to directly identify, simply by reading the database, a way allowing to go from a given point of the airport to another point while respecting a succession of predefined elements.
In order to try and solve this difficulty, the document WO-2009/016135 describes a method for creating an additional layer, in addition to the current databases, which enables to connect the different elements to the database between them. However, this solution has some disadvantages. In particular, the connectivity layer is defined on the ground on the whole airport surface and is subjected to an additional database which is loaded in the airplane at the same time as the airport database ED-99B, which forces the airline to load a second database of an important size, thus causing an immobilization of the airplane more important than required for the loading of the single airport database.
Other solutions could be envisaged on the base of a new airport database format, which can be discussed within the scope of standardization activities, but may lead to major evolutions of the tools currently used by database providers and may need important investments. Furthermore, such standardization activities are always very long, and the availability of a new standard (ED-99C), taking into account the requirements of any connectivities required for the running trajectory direct generation, could take many years.
The present invention aims at remedying the above mentioned disadvantages. It relates to a method for aiding the piloting of an aircraft, in particular a transport airplane, running on the ground, which comprises a process for generating a taxiing trajectory of the aircraft on the airport domain.
To this end, according to the invention, the method is remarkable in that:
Thus, thanks to the invention, the method allows a trajectory to be generated, which can be followed by the aircraft when it has to follow the required path by running on the ground. Such a trajectory on the ground can be provided to a piloting aiding device such as an automatic piloting system which allows to get the aircraft to automatically follow this trajectory. This latter can also be provided to piloting aiding device such as a displaying system likely to generate a visual representation of this trajectory on an appropriate viewing device, this visual representation being likely to be used by the pilot for aiding him to manually guiding the aircraft along the trajectory.
Thus, the present invention proposes to extract from the airport database being used a succession of polylines corresponding to a path to be followed, which is received in particular from a controller, and to convert these polylines in a succession of curves forming a trajectory, likely to be followed by the aircraft and to be used including by a guiding element for an automatic taxiing system.
In particular, for the implementation thereof, the present invention does not need to load on-board the aircraft a second additional database, like the solution recommended by the above mentioned document WO-2009/016135, nor a new airport database standard taking into account connectivity requirements necessary for the direct generation of a running trajectory.
Within the scope of the present invention, the connectivity information includes, for instance, for any surface element (or polygon), all the surface elements (or polygons) which are connected thereto, as well as all the polylines partially or completely included within the surface element, and all the points included in said surface element.
In a first embodiment, at step c), the following operations are implemented consisting in:
Although not exclusively, the method according to this first embodiment of the invention is applied more particularly to a common airport database according to the ED-99B standard, which allows to remedy the above mentioned disadvantages.
Furthermore, in this first embodiment, advantageously, if at step c1) two successive surface elements are neither connected, nor connectable by an auxiliary surface element, the implementation of the method for generating a taxiing trajectory is even continued.
Moreover, in a second preferred embodiment, at step c), the connectivity information is directly extracted from an appropriate database which comprises, in addition to the surface elements and polylines, at least information indicating, for each surface element, the whole of the surface elements being connected thereto. The description will show thereafter a method for determining such a database comprising connectivity information.
The following features apply to each one of the first and second above mentioned embodiments of the method according to the invention.
Advantageously, for the surface elements extracted from the database, the following operations are performed:
Additionally, advantageously, at step d), in order to identify the starting and arrival points of the path, when the starting and arrival points are neither explicitly mentioned nor calculated from the aircraft position, each time the whole of the polyline ends located outside the corresponding surface element (that is the first surface element of the path for the starting point, and the last surface element of the path for the arrival point) is considered.
Furthermore, advantageously, at step e):
Furthermore, advantageously, if at step e), no continuous way linking starting and arrival points has been found, the longest way up to discontinuity is chosen, that is used for the following steps.
Moreover, in a preferred embodiment, at step f), the polylines are converted into a succession of Bezier curves in order to obtain a taxiing trajectory for providing the curvature radius continuity on the whole trajectory.
The use of Bezier curves has a double interest:
The present invention also relates to a system for aiding the piloting of an aircraft, particularly a civil or military transport airplane, taxiing on an airport domain such as an aerodrome or an airport.
According to the invention, the piloting aiding system is remarkable in that it comprises:
In a first embodiment, the connectivity detecting device comprises:
Furthermore, in a second preferred embodiment, the connectivity detecting device comprises a connectivity extracting device for extracting connectivity information from the database which, in this second embodiment, comprises, in addition to the surface elements and the polylines, at least information indicating, for each surface element, the whole of the surface elements being connected thereto.
The present invention also relates to an aircraft, particularly a transport airplane which is provided with a piloting aiding system, as the above mentioned one.
The FIGS. of the attached drawing will help to understand how the invention can be implemented. In these FIGS., like reference numerals relate to like components.
The system 1 according to the invention and schematically shown on
According to the invention, the system 1 being on-board the aircraft comprises:
The trajectory generating device 2 is designed for generating a taxiing trajectory which is such that the aircraft can be manually or automatically guided along such trajectory on the airport domain. Thus, this trajectory on the ground shows a way to be followed by the aircraft on the airport domain, comprising particularly the takeoff and landing runways, the taxiways, the turning-around areas, the waiting zones, the stop bars, the stand positions, the maneuvering areas and the parking areas.
According to the invention, the trajectory generating device 2 comprises:
Thus, the trajectory generating device 2 according to the invention allows a trajectory to be generated which can be followed by the aircraft, when it has to cover the required path by taxiing. This trajectory on the ground can, amongst other things, be provided to piloting aiding device according to the invention allows a trajectory to be generated which can be followed by the aircraft, when it has to cover the required path by taxiing. This trajectory on the ground can, amongst other things, be provided to piloting aiding device such as an automatic taxiing system 4 which allows to get automatically the aircraft to follow this trajectory. This latter can also be provided to piloting aiding device such as a displaying system 5 which is likely to generate a visual representation of this trajectory on an appropriate viewing device such as a displaying system 5 which is likely to generate a visual representation of this trajectory on an appropriate viewing device, this visual representation being usable by the pilot for aiding him to manually guide the aircraft along the trajectory.
The present invention thus proposes to extract from the airport database 3 being used, a succession of polylines corresponding to a path (to be followed) which is received, in particular, from a controller, and to convert these polylines into a succession of curves forming a trajectory, for a simple and robust guiding of the aircraft and which can including be used by an guiding element of an automatic taxiing system 4.
In a first embodiment shown on
Although not exclusively, this first embodiment (
Furthermore, in a second preferred embodiment shown on
The thus completed database allows then the graphic displaying of the airport and includes the connectivity information used by the second embodiment of
Consequently, thanks to the trajectory generating device 2 according to the invention:
In a particular embodiment, the navigation device 8 can be:
Moreover, the database extraction device 9 extracts from the database 3 surface elements or polygons (runway, taxiway, . . . ), from their names identified in the path (received from the navigation device 8). For illustration, in the example of
A search is thus performed in the database 3 for each identifier of the path. This search allows to find all the surface elements defined by an identifier (14L-32R, M8, S8, . . . ), that is the surface elements E1 to E9 in the example of
Furthermore, the connectivity testing device 10 (
Several surface elements can have the same identifier. For illustration, the surface elements E8 to E9 have the same identifier W40 in the example of
For that, the connectivity testing device 10 checks that each extracted surface element has at least two common points with an other surface element having the same identifier or the identifier that comes after in the path, which allows not only to be sure that the list of the extracted surface elements shows a continuous path, but also to order the list of the surface elements according to the order to be followed so as to cover the path from the first surface element to the last surface element (the surface elements corresponding to a same identifier could be ordered in reverse direction after the extraction operation).
If the above mentioned connectivity test fails (a surface element of the path having no point in common with the elements corresponding to the same identifier or to the identifier coming after in the path), a search in the database 3 is performed, by the connectivity testing device 10, to recover, if any, the surface elements (up to two) connected both to this element as well as to one of the surface elements corresponding to the same identifier or to an identifier coming after in the path.
This search aims at forming a continuous sequence of surface elements corresponding to the clearance. For instance, in case a surface element is wrongly or not identified in the airport database 3, the extraction of the surface elements (database extraction device 9) does not come out this element. For illustration, in the example of
This search also covers the case where the aircraft does only cross a landing runway, as illustrated for instance on
If two successive surface elements are neither connected, nor connectable by a third surface element, the connectivity testing device 10 concludes that these two successive elements of the path cannot be connected between them. However, the treatment implemented by the device 2 is followed, without displaying any error messages. Indeed, it is however possible, in certain cases, to recover a way without having necessarily connected all the surface elements to each other.
The database extraction device 11 (
To this end, the database extraction device 11 performs for each surface element, a first test on the coordinates of the whole of the polyline points, in order to eliminate the polylines being too far from this surface element. Indeed, if no coordinate of the polyline points is in an interval defined by minimal and maximal terminals of the coordinates of the surface element points, the polyline being considered is located outside this surface element.
Then, for each point P1, P2, P3 of the remaining polylines, said means device 11 performs a second test consisting in counting the number of intersections between the length L1, L2, L3 linking this point P1, P2, P3 to a fixed point P4 (located away outside the airport area) on the one hand (infinite half-line), and the lengths defining the contour of the surface element Ei on the other hand, as shown on
If the number of intersections 12 is odd, the point P2 of the length L2 belongs to the considered surface element Ei.
In the opposite case, that is in presence of a number of intersections I3A, I3B pair or nil (for L1), the point P3, P1 is located outside the considered surface element Ei.
At this point of the treatment, the trajectory generating device 2 allowed to recover the whole of the guiding lines connected to surface elements corresponding to the path of the controller.
Furthermore, the starting and arrival point detecting device 12 of the trajectory generating device 2 automatically identifies the starting and arrival points of the path.
To this end, the origin point can be:
A1) explicitly mentioned in the path; or
A2) determined from the aircraft position; or also
A3) determined according to the path.
In the case A2), knowing the aircraft position and the path, a test is being performed by the starting and arrival point detecting device 12 on the polylines located in the surface element where the aircraft is situated. The origin point is then the extreme point of the polyline the closest to the aircraft position.
Furthermore, in the case A3), where determining the origin point from the sole path is looked for, the starting and arrival point detecting device 12 extracts all the polylines L4, L5, L6 having at least one point in the first surface element Ej (element the identifier of which is in first in the path), not completely included in this first surface element Ej, and the origin points are the extreme points, of the previously identified polylines, outside this element. The different possible ways are displayed in dotted line up to the convergence point Pc, for instance by the displaying system 5.
Then, it belongs to the aircraft crew to select the desired way from those thus presented in dotted line (by directly designating it on the map for instance).
Moreover, the starting and arrival point detecting device 12 also identifies the arrival point(s) of the path. As for the origin point, the arrival point can be explicitly mentioned in the path. In the opposite case, the starting and arrival point detecting device 12 proceeds as for the origin point, without however performing the test with respect to the aircraft position. The starting and arrival point detecting device 12 thus extracts the whole of the polylines having at least one point in the last surface element (element the identifier of which is the last in the path) not completely included in the last element of the path, and the arrival points are the extreme points, the polylines previously identified, outside this element. As for the origin point, the different possible ways are displayed in dotted line from the divergence point, for instance by using the displaying system 5.
The continuous way determining device 13 then determines, automatically, the way linking the starting and arrival points defined by the starting and arrival point detecting device 12, by covering the whole of the polylines extracted from the database extraction device 11.
To this end, the continuous way determining device 13:
The continuous way determining device 13 considers the whole of the ways (succession of polylines) starting from the starting point and the continuous way determining device 13 only shows the ways ending with the arrival point.
Furthermore, the continuous way determining device 13:
The continuous way determining device 13 thus allows to isolate from the whole of the extracted polylines of the base 3, those defining the way to be covered, while checking that these polylines are connected between them (thus that the way is continuous) and that the trajectory can be followed by the aircraft (test on the course change between two polylines).
It should be noticed that even though the surface elements are not all connected between them, nevertheless it is possible to calculate a pathway, since the device 2 is only based on the polylines for the calculation. Thus, if there is no continuous way linking the origin point to the arrival point, the system 1 according to the invention:
Furthermore, the conversion device 14 then converts the polylines T1 (
To this end, the conversion device 14 calculates, for each polyline, the Bezier curve passing at most through all the points of the polyline. A Bezier curve is a parametric, polynomial curve, defined by check points. For instance, in the case of the Bezier curve of order 3, the curve is defined by four check points PC1, PC2, PC3 and PC4. The check point positions determine the curve pace.
Thus, to provide continuity to the curvature radius along the trajectory, it is necessary to avoid any discontinuity (breakdown) between two consecutive Bezier curves. To this end, the check points must be located on the tangents previously calculated depending on the previous and following polylines.
The extreme check points of the Bezier curves are the extreme points of the polylines defining the pathway.
The intermediate check points are determined in an iterative way by varying their position along the tangents at the polyline input and output points in order to minimize the mean quadratic deviation between the corresponding Bezier curve T2 and the points of the polyline T1 (
The use of Bezier curves has a double interest:
In order to obtain a database such as used by the system 1 of
As indicated above, the current databases, defined according to the standard ED-99B, have been foreseen to graphically represent the airports. Effectively, the airport elements defined in these databases are juxtaposed. The on-board system makes do with reading the databases, interpreting the information defining the various constitutive elements of the airport and displaying them for graphically rendering the guiding surfaces or lines. The current databases contain three types of elements:
These elements are defined by their geometry (coordinates of the points bounding the element) and by attributes (identifier corresponding to the identifiers of the airport maps AIP, identification number, type, . . . ).
The method according to the invention depends on the existing databases, defined according to the applying standard ED-99B. As indicated above, several solutions have already been studied, but these solutions are dependent on a new non standard format of databases (thus not available today), which would be optimized to manage the connectivity of the different elements of the airport, thus making the generation of the running trajectory easier.
The principle of the method according to the present invention consists in:
More precisely, the method according to the invention is a method for generating connectivity information between airport elements:
According to the invention, the proposed method presents the following steps:
This operation, detailed hereinabove, to complete the database can be performed as well on the ground, before being loaded on the aircraft, or on-board the aircraft during loading (the database is then loaded in the format ED-99B, then the aircraft systems convert the base ED-99B before using it in the aircraft).
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