This application claims priority of French Patent Application No. 17 01093, filed on Oct. 20, 2017.
The present invention relates to the field of the secure use of a provisional itinerary. A provisional itinerary for an aircraft is often calculated using tools on the ground. The provisional itinerary can next be modified by the teams on the ground or in flight.
A provisional itinerary refers to the flight plan or the path of an aircraft. It generally comprises identifying a series of waypoints associated with a speed of the aircraft and an anticipated passage time by these waypoints, all of which is calculated so as to reduce fuel consumption.
The securing of a provisional itinerary seeks to guarantee inter alia that on the one hand, the itinerary does not clash with elements presenting a potential threat for the aircraft, such as:
The present invention more specifically relates to a method, implemented by computer, for securing a provisional itinerary calculated for an aircraft with respect to a set of elements representing potential threats, each element being associated with characteristics comprising at least geographical coordinates, according to which the calculated provisional itinerary for the aircraft comprises a list of waypoints of the aircraft each associated with geographical coordinates, two successive waypoints defining an anticipated route segment with said two waypoints as ends; said method comprising the following steps:
a first step for detecting risks is carried out based on at least the geographical coordinates of the ends of each segment and at least the geographical coordinates of the elements for identifying one or more (segment, element) at-risk pairs where the element of such a pair presents a safety risk for the aircraft in the segment of said pair.
The devices for securing a provisional itinerary calculated for an aircraft generally only take a limited set of threats into account. They are suitable for validating an itinerary calculated only by them on the one hand, and on the other hand, they require very substantial computing power, since they are based on complete sampling of the itinerary.
Furthermore, other elements make it possible to secure a calculated route: messages from air traffic services (ATS) sent to aircraft and coordinating the traffic of various aircraft, messages relative to the weather from the flight information service. Alerts from the terrain awareness and warning system (TAWS) also contribute to securing the few minutes of flight that come from a calculated itinerary (typically 2 min.), by detecting, on this timescale, an abnormal configuration of the vehicle (i.e., landing situation and non-deployed landing gear), proximity to the terrain or obstacles compared to flight parameters (speed, altitude) with abacuses. The significant volume of data to be analyzed to secure a provisional itinerary comes, in multiple formats, from various sources, depending on the nature of the data, the timescale of interest (short or long term), the geographical environment in question (close to the runway, over the ocean when the vehicle is cruising), making the synthesis that much more complex to carry out.
To that end, according to a first aspect, the invention proposes a method, carried out by computer, for securing a provisional itinerary calculated for an aircraft of the aforementioned type, characterized in that each segment being split into segment sections each associated with geographical coordinates, a second risk detection step is next carried out for each (segment, element) at-risk pair identified in the first step, in order, based on at least the geographical coordinates of the sections of the segment of the pair and at least the geographical coordinates of the element of the pair, to determine whether said element is confirmed as presenting a collision risk with the segment of said pair.
The present invention, by first proposing a macro-analysis, then a detailed analysis done only on the elements detected as critical during the macro-analysis, thus makes it possible to reduce the computing resources necessary to validate and secure the anticipated itinerary.
In embodiments, the securing method according to the invention further includes one or more of the following features:
According to a second aspect, the present invention proposes a system for securing a provisional itinerary calculated for an aircraft with respect to a set of elements representing potential threats, each element being associated with characteristics comprising at least geographical coordinates, the calculated provisional itinerary for the aircraft comprising a list of waypoints of the aircraft each associated with geographical coordinates, two successive waypoints defining an anticipated route segment with said two waypoints as ends, said securing system being suitable for performing a first risk detection operation, as a function of at least the geographical coordinates of the ends of each segment and at least the geographical coordinates of the elements for identifying one or more potentially at-risk (segment, element) pairs as a collision risk potentially exists between the element of such a pair in the segment of said pair;
said system being characterized in that it is capable, each segment being split into segment sections each associated with geographical coordinates, of carrying out a second risk detection step for each (segment, element) at-risk pair identified in the first step, in order, based on at least the geographical coordinates of the sections of the segment of the pair and at least the geographical coordinates of the element of the pair, to determine whether said element is confirmed as presenting a collision risk with the segment of said pair.
According to a third aspect, the present invention proposes a computer program comprising software instructions which, when executed by a computer, carry out a method according the first aspect of the invention.
These features and advantages of the invention will appear upon reading the following description, provided solely as an example, and done in reference to the appended drawings, in which:
The securing platform 1 has a securing system 2, a mission planning tool 3, a restriction provision tool 4, a terrain database (DB) 5, storing terrain elevations, MEA altitudes and obstacle definition data, traffic monitoring systems 6, weather servers/stations 7, a configuration tool 8 and a UTC date and time server 9.
In the considered embodiment, the securing system 2 has:
The operations performed by the various units of the securing system 2 in the considered embodiment are described below. All, or at least some, of these operations are implemented via the performance, on the calculating means of the securing system, of computer program software instructions.
The unit 10 is suitable for receiving, as input, for example from a mission planning tool 3, a flight plan of the aircraft comprising waypoints (a starting point, an arrival point, midpoints between them). Each waypoint is associated with geographical data, for example latitude, longitude, altitude and predicted passage time of the aircraft.
The itinerary portion between two successive waypoints is referred to below as a segment (it is also known as a leg).
In one embodiment, the flight plan further indicates the changes between the different flight phases (end of takeoff, end of climb, beginning of descent, beginning of approach).
Furthermore, the unit 10 is suitable for receiving, as input, for example from the configuration tool 8 of the securing system 2, margin values to be applied between the extreme latitude and longitude values of each segment so as to provide an overlap of the geographical boxes produced by the unit 10, as described below.
According to the embodiments, the margins are set independently of the flight phases, or depend on the flight phases. In one embodiment, the margins vary dynamically and are provided by an external system.
The unit 10 is suitable for receiving, as input, a position error of the vehicle, for example coming from the configuration tool 8. According to the embodiments, this position error varies dynamically during the flight and is provided by an external system, or this position error is defined beforehand for the flight plan.
The provisional itinerary processing unit 10 is suitable for carrying out, in reference to
Each 2D box is then associated with an entry time He, an exit time Hs (respectively corresponding to the smallest and largest of the passage times of the aircraft at the ends of the segment) and a minimum and maximum altitude of the segment (Alte, Alts), which are, in the particular “monotonous linear function on each segment” case being considered, the altitudes of the ends of the segment. A 4D description of the box is thus obtained (3D box corresponding to the longitude/latitude/altitude coordinates+temporal dimension).
This list of boxes thus provides a rough depiction of the flight plan.
The provisional itinerary processing unit 10 is further suitable for building a simplified flight plan, comprising the altitude constraints and estimated passage times. To that end, it is capable of subdividing each segment of the flight plan into fixed-sized sections, equal to or smaller than a given maximum size. The purpose of this step is to avoid managing overly large sections (a segment may measure several hundred nautical miles) and to account for the roundness of the Earth in the calculations (orthodromic path).
For straight segments, this subdivision is done by simply dividing each straight segment into several sections of predefined length, and while following the orthodromic heading.
Arc-of-circle segments are approximated by a series of straight sections. To that end, an algorithm of the Ramer-Douglas-Peucker type is for example used (for example using the tolerance equal to the position error divided by 2). Each obtained section is next subdivided again if necessary.
In one embodiment, the predefined and/or maximum section size varies based on the type of segment (straight or arc of circle) and/or the flight phase.
The provisional itinerary processing unit 10 is suitable for calculating and associating with each obtained section: an entry time (H′e) of the aircraft, in the section, and an exit time from the section (H's) corresponding to the passage time of the aircraft by the end of the section, and a passage altitude (Alt′e, Alt's) by these points. To that end, a linear variation algorithmic method is used between the points of the sections and the entry point and the exit point of the segment of the initial flight plan.
Then, the provisional itinerary processing unit 10 is suitable for associating, with each geographical box, the list of sections of the segment that it encompasses, the associated characteristics and the associated flight phases.
In the considered embodiment, the unit 10 is suitable for extracting, from the flight plan, the information indicating the arrival airport, the type of approach and the anticipated arrival runway, as well as the estimated time of arrival (“ETA”).
These two sub-steps for building geographical boxes and building a simplified flight plan are carried out upon each change of flight plan or each new flight plan and can be done in any order of precedence.
The provisional itinerary processing unit 10 thus provides, as output, in particular for the unit 11 and the polygon processing units 18, 19, 20, 21:
The provisional itinerary processing unit 10 thus provides, as output for the arrival airport processing unit 17, the information indicating the airport, the type of approach, the arrival runway and the estimated time of arrival (“ETA”).
The unit 11 processing potential threats for the aircraft is suitable for receiving, as input, the list of geometric boxes and the flight plan subdivided into sections supplied by the provisional itinerary processing unit and for supplying these data to the processing units 11 to 14 suitable for processing the data representing the various potential threats.
The unit 12 for processing terrain elevation data is thus suitable for receiving as input:
In the considered embodiment, with the aim of preserving the computing load, the cruising phase is analyzed roughly first, and more finely secondly, and only over the zones presenting a risk according to the first rough analysis. In the considered embodiment, furthermore, the phases closer to the ground (takeoff phase and descent/approach phase), if they are included in the flight plan, are analyzed finely and systematically (in other embodiments, it is more generally the flight phases beyond a certain altitude that are analyzed more roughly first, and more finely secondly only over the zones presenting a risk according to the first rough analysis; the flight phases below said certain latitude being analyzed finely and systematically). To do this, in reference to
For the cruising phase, in a sub-step 103a:
For the takeoff and landing phases, the unit 12 is capable of taking the sections of the 4D flight plan that are entirely or partially included in said phases and directly applying sub-step 103b to said sections to identify, among them, the sections at risk of collision and the associated risk level.
These operations are carried out by the terrain elevation data processing unit 12 upon each change of flight plan or each new flight plan.
Each unit 12 thus delivers, as output, the list of sections identified as collision risks with the terrain and the associated risk level.
This unit 13 processes the obstacles derived from man-made structures, which may be periodic (for example, buildings) or linear (for example, high-voltage lines, telephone cables, illuminated marking elements, etc.).
It receives, as inputs:
the list of geographical boxes;
from the DB 5: the geographical coordinates of fixed obstacles, whether periodic or linear, their height, as well as the uncertainty related to these characteristics (this information may be built in the DB 5 statically on the ground and/or dynamically using information entered by an operator or supplied by one or more sensors).
The unit 13 serves to extract the relevant obstacles in polygon form. It is thus capable, upon each change of flight plan or each new flight plan and in case of change to the list of obstacles, in reference to
extracting the obstacles whose latitude and longitude are contained in the 2D section, according to the latitude and longitude coordinates, of the geographical box and depicting each extracted obstacle in the form of a polygon in the latitude/longitude plane, with the associated height (if this height information is not available for the obstacle in question, it is considered infinite);
comparing the height of each obstacle, including a margin and the uncertainty associated with the minimum altitude of each geographical box;
in case of conflict (i.e., if the added height with margin and uncertainty exceeds the minimum altitude of the box or is lower but not by a given minimum distance), identifying the polygon as an “at risk” polygon and determining the associated risk level according to predetermined criteria.
It provides, as output for the obstacle-type polygon processing unit 19, a list of polygons associated with each geographical box and representing the obstacles that can be “at risk”, including, for each polygon, the longitude/latitude coordinates of the various points of the polygon, the high altitude and the low altitude of the polygon (generally nil), comprising the position uncertainty, the height uncertainty, the nature of the obstacle (linear, periodic, etc.) and the risk level.
The unit 14 receives, as input:
the current “UTC” (universal time coordinated) date and time of the UTC server 9;
the list of geographical boxes;
a list of weather operators/servers 7 on the ground and covered geographical zones respectively associated with the weather stations/servers; typically, these stations/servers have information of the SIGMET (“SIGnificant METeorological Information)” type;
lists of grouped polygons, coming from the weather stations/servers 7 (in response to a request, as described hereinafter). Each list includes a group of polygons used to represent a weather object (a storm, an anticipated turbulence zone, a thunderstorm, ice, etc.) and its evolution over time using a temporal tag. The polygons contained in this list intersect such that there is no geographical space between two adjacent polygons in a same group;
a temporal margin derived from the configuration of the device or an external system.
The weather data processing unit 14 is suitable, in reference to
building the request(s) with weather operators 7 to cover each geographical box of the list (these requests are generally much more encompassing and may for example cover the various countries flown over by the aircraft),
then, periodically in order to recover up-to-date weather data (the weather data relative to a geographical zone), sending the built requests to the weather operators 7: a new request iteration is thus done periodically on all of the geographical boxes for which the entry time in the box is greater than the current UTC time and, if applicable, for the box whose entry date and exit date frame the current UTC time;
processing the received responses by merging them to convert them into a list of valid sequenced polygons at the time of the request; the polygons are defined in the longitude/latitude plane and are associated with a low altitude and a high altitude, thus geographically bounding the weather phenomenon at a given time;
sequencing the lists of polygons by geographical coordinates, by temporal tagging and by high altitude. During this step, only the polygons are kept:
that are contained in one of the geographical boxes (to determine this, a simple comparison of the latitudes/longitudes is done), and
for which the start date of the phenomenon is earlier than the exit date of the aircraft from the box and for which the end date is after the entry date of the aircraft into the box, and
that are associated with a weather phenomenon that may present a risk.
The weather data processing unit 14 therefore provides an output, intended for the weather polygon processing unit 21:
a list of polygons attached to each geographical box and sequenced by longitude, latitude geographical coordinates, by temporal tagging and by altitude
the type of weather risk associated with each polygon.
The traffic data relative to the air or other traffic (maritime, for example) is sent periodically and come from collaborative systems (i.e., sending data from ADS-B, flarm or AIS systems) and/or non-collaborative systems (i.e., the position and heading or speed information of which are transmitted by a third party, such as the air traffic control “ATC” service on the ground or by a radar or electro-optical sensor, for example).
The unit 15 has, as input:
The traffic data processing unit 15 is capable of processing the received traffic data to convert it into a list of sequenced polygons.
Thus, during a process 106 for processing traffic data, in reference to
recovering the list of traffic data;
sequencing the traffic elements by geographical coordinates and by altitude. During this step, the only traffic elements kept are those for which the longitude/latitude are contained in the section, in the surface of the longitude and latitude, of at least one of the geographical boxes: to determine it, a simple comparison of the latitudes/longitudes of the traffic elements and boxes is thus done;
converting the traffic elements into polygons using the characteristics (latitude, longitude, altitude) and associating therein, with each polygon, the speed of the corresponding traffic element and the uncertainty of the element (the uncertainty indicates the imprecision regarding the position of a traffic element; it is taken into account for example by increasing the size of the polygon based on the period in which the traffic data is received, the precision of the source data and the speed of the considered traffic element).
The traffic data processing unit 15 therefore provides as output, intended for the traffic polygon processing unit 20:
It will be noted that according to the embodiments, this traffic data provided at the output of the traffic data processing unit 15 may next be processed separately from the obstacles (in the case at hand, respectively by the traffic polygon processing unit 20 and by the obstacle polygon processing unit 19), or in a merged manner, independently of the origin of the polygons.
Restrictions in particular indicate zones prohibited by air traffic control or at-risk zones (for example following a fire, a war, etc.), zones prohibited by the operator of the aircraft, zones that are uncomfortable to pass through in terms of weather or runway condition, etc.
They are for example sent via E-NOTAM (Electronic-Notice To Air Men) messages called restriction messages.
The unit 16 for processing restrictions receives as inputs:
The E-NOTAMs being sent when they are created, the restriction processing unit 16 builds a request for each geographical box in the list, defined by its 2D longitude and latitude coordinates. This request seeks to receive all of the E-NOTAMs applicable to this box at the moment of the request in response.
The restriction processing unit 16 is capable, in a step 107a of a process 107 for processing restriction data and in reference to
The unit 16 for processing restrictions therefore provides, as outputs:
The processing unit 17 for the arrival airport receives, as inputs:
The arrival airport processing unit 17 is capable, upon each change of flight plan or new flight plan, of:
The causes may be: runway closed, maintenance action on equipment needed on the approach, etc.
And if it has been determined as calling the mission into question, producing an associated restriction message, containing:
The arrival airport processing unit 17 provides, as output, a landing restriction message related to the arrival airport, intended for the consolidation unit 22.
A polygon processing unit such as one of the polygon processing units 18, 19, 20, 21 receives, as input:
Each polygon processing unit 18 to 21 is capable of determining the collision risks between a respective type of polygon (weather, traffic, etc.) that is presented to it and the flight plan.
It is thus capable, upon each change of flight plan or each new flight plan, as well as in case of update of the list of polygons, of carrying out the operations described below in a step 104b for the processing unit of the obstacle polygons 19, based on the list polygons provided by the obstacle processing unit 13, in a step 105b for the weather polygon processing unit 21, based on the list of polygons provided by the weather data processing unit 14, in a step 106b for the traffic polygon processing unit 20, based on the list of polygons provided by the traffic data processing unit 15, in a step 107b for the restriction polygon processing unit 18, based on the list of polygons provided by the restriction processing unit 16.
Thus, a polygon processing unit 18, 19, 20 or 21 is capable of:
taking for each geographical box, the list of path sections that are associated with it as well as the list of polygons attached to the box received as input by the polygon processing unit;
for each polygon:
for each apex of the polygon:
For each pair of entry/exit points thus obtained, a passage time of the aircraft is next determined by using a linear variation of the speed along the itinerary section containing the entry and exit point, respectively. This passage time is next compared to the temporal validity tag of the polygon (if one exists).
If the determined passage time increased or decreased by the temporal margin (this temporal margin received as input corresponds to the time delta that the aircraft using the system 2 may have relative to the forecasts done regarding its entry and exit from a geographical box) fits with the temporal validity tag of the polygon (i.e., the temporal tag is comprised within the [determined passage time-margin, determined passage time+margin] interval) or if there is no temporal validity tag (the polygon is in this case considered always to be valid), then there is a collision risk and the polygon is identified as “at risk” by the polygon processing unit.
If the polygon is associated with a speed vector (case of traffic elements, for example), the level of the determined risk for the polygon may be modulated, or the “at risk” identification canceled, based on the amount of time needed for the aircraft to reach the 1st point of entry into the polygon. Given that the flight plan information of the polygon is not available, in order to determine the risk level, the hypothesis is adopted that the object associated with the polygon may stop or change direction.
In the considered embodiment, the polygon processing unit identifies the path sections having a collision risk with a threat: these “at-risk” sections (Seg x) are all of the path sections located, in whole or in part, between a point of entry Ex into a polygon as calculated above and the exit point from said polygon, or the last of the consecutive exit points Sx encountered according to the flight plan from this exit point from said polygon in the case where said exit point is followed by other polygon exit point(s) without polygon entry point arranged between them. In reference to
In one embodiment, a risk avoidance limit point is further calculated by the polygon processing unit, for example positioned upstream from the point of entry along the flight plan at a distance D depending on the speed of the aircraft at the time of entry into the path section identified as “at risk”. The distance D is calculated taking into account a time needed to perform the avoidance, which depends on the speed of the aircraft (the faster it goes, the less maneuverable it generally is).
In one embodiment, the polygon processing unit further identifies, as “to be watched”, the polygons outside the corridor, but the distance d of which from the flight plan is below a certain threshold and for which the speed vector converges toward the flight plan. Given that the flight plan information of the polygon is not available, the hypothesis is adopted that the object associated with the polygon may stop or change direction.
In the considered embodiment, each polygon processing unit 18, 19, 20, 21 delivers, as output, to the consolidation unit 22:
In the considered embodiment, the polygons associated with one threat type are processed independently of the polygons associated with other threat types, by respective polygon processing units. In other embodiments, a global processing unit processes all of the polygons together.
The consolidation unit 22 uses, as input data:
The consolidation unit 22 is capable, upon each change of flight plan or new flight plan, as well as in case of update to the threat list, in a step 108, in reference to
Depending on the embodiments, the securing system 2 may be installed fully in a ground mission preparation system or be completely on board the aircraft. In another embodiment, the processing operations are distributed between the ground and the aircraft, for example the obstacle processing unit 11, responsible for collecting data and formatting it, is on the ground, while the other processing operations, responsible for analysis and verification, are on board. Data transmission means are then implemented between the two parts. The interest of this device lies in concentrating data collection and formatting as close as possible to the suppliers of this data.
The invention, by first performing a macro-analysis of the provisional itinerary, then a detailed analysis done only on a subset of threats related to a subset of route sections identified as critical during the macro-analysis, makes it possible to reduce the necessary computing resources.
The invention also makes it possible to guarantee, quickly and reliably, the viability (within the meaning of cybersecurity) of an itinerary provided by an external system (of the ground station type) without using complex and costly encryption in terms of computing time.
The use, in the considered embodiment, of polygons to depict various threats makes it possible to pool and streamline the algorithmic processing operations done, which again allows a gain in terms of computing resources.
The invention proposes not only to validate that a calculated itinerary is secured, and further accounts for the evolution, over time, of the risks related to the provisional itinerary.
In the considered embodiment, an overall status is thus provided to the crew, relative to all of the threats and the entire provisional itinerary.
The invention has been described in an embodiment taking account of threat elements of various types and proposing a wide variety of processing operations. Of course, in other embodiments, only certain types of threat elements are taken into account in a securing system, for example the terrain elevation and periodic and linear obstacles, and only some of the described processing operations are implemented, for example without restriction processing, or arrival airport processing, etc.
Number | Date | Country | Kind |
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17 01093 | Oct 2017 | FR | national |