EP1955305B1 - Device and method for dynamically updating prohibited flying areas in an aircraft - Google Patents

Abstract

The invention relates to a device and method for dynamically updating prohibited flying areas on a flying aircraft board. The inventive method consists in defining the geometry of restricted areas and the entry conditions thereto depending on the aircraft, in characterising the aircraft with respect to the conditions for entering said areas and in determining the flying areas prohibited for the aircraft. Said invention can be used for aeronautics.

Description

The present invention relates to a device and a method for changing the prohibited zones to an aircraft. It applies in the field of aeronautics. For example, in the context of avionics and embedded systems, it applies to systems intended to avoid the planet, such as the systems known by their Anglo-Saxon name of "Terrain Awareness and Warning Systems", that we will call TAWS systems later.

TAWS systems and global avoidance systems are systems on board aircraft designed to mitigate any control or flight errors that could cause an aircraft to collide with the ground or with is commonly referred to in aeronautics by the Anglo-Saxon expression "Man Made Structure", which will be called MMS thereafter. MMS are human ground constructions that constitute a potential obstacle to air traffic because of their size, especially when the aircraft are in the process of taking off or descending to an aerodrome. Among these obstacles, can be mentioned for example broadcast antennas, power lines or skyscrapers.

It is essentially air traffic control which ensures the respect of the safety distances between the aircraft and the ground and which signals the MMS, even if the crew also has paper or digital maps providing information on the approach procedures. or take-off and on the threats, MMS or others, that he may encounter. The approach controller gives climb or descent instructions to the radio pilot, who executes the instructions in a fully assisted manner. But the execution of these instructions is entirely subject to the will or the availability of the pilot. In the case where the pilot is no longer able to receive or execute the instructions of the controller, if there is misappropriation by hijackers for example, there is no system on board that can substitute for the controller and the driver. Indeed, even if edge allow to measure more or less accurately the altitude of the aircraft, based on a pressure measurement and the application of a gradient from a reference pressure, to know precisely the distance with the soil is much more complex. This requires in particular having a detailed knowledge of the terrain, the human infrastructure on the surface, and being able to exploit them quickly in view of the enormous amount of information that this represents. This is the role of increasingly widespread avoidance systems, such as TAWS systems.

For example, current TAWS systems have a connection to a triangulation positioning system such as "Global Positioning System" for example, or a connection with radio navigation equipment on the ground and on board allowing them to know their position in three dimensions. They deduce their position in latitude and longitude as well as their altitude in relation to the sea level. They also have a digital terrain model fed by a terrain database allowing, for any position of the space characterized by a latitude and longitude, to know the altitude of the terrain relative to the sea level. By comparing the altitude of the aircraft with the altitude of the relief, these systems deduce the distance of the aircraft from the ground, inform the flight crew and possibly raise audible or visual alerts in cases of imminent risk of collision with the ground. These systems also include a means of storing MMS, which are described by their position in latitude and longitude, their altitude relative to the consistent sea level of the on-board digital terrain model and finally by their height. Each MMS is associated with a radius and an uncertainty sometimes expressed in kilometers, these two parameters being supposed to translate the lack of precision as for the location and the scale of the obstacle. Such a representation of obstacles is only suitable for occasional obstacles, of the type of an antenna, a pylon or an isolated tower, but absolutely not to volume obstacles, such as sets of skyscrapers, except to introduce very large safety distances by increasing the radius and uncertainty to encompass these obstacles.

However, the current needs tend towards the precision in the definition of the obstacles, going up to require to be able to take into account large but distinct large volume obstacles and to adapt the safety distance in certain situations. For example, a concentration of skyscrapers may be prohibited from flying over and approaching any airliner traffic at a significant distance. But the flight of light aircraft can be authorized at medium distance. Helicopters may be allowed to land on infrastructure near skyscrapers, so they must be able to approach very short distances. For example, some equipment that fails can make a device less reliable or less secure. Prohibiting the proximity of certain obstacles whose approach would require the use of equipment breakdown is a measure that goes in the direction of flight safety. For example again, it is better to prevent the approach of MMS with high concentration of population like skyscrapers to a hijacked plane by hijackers.

The current TAWS systems and the way of modeling the MMS they implement do not allow such a level of precision and flexibility. Thus, obstacles of rather small scale generate a vast sector of flight prohibited to all. Aircraft that have no contraindications to the approach of certain obstacles are permanently banned from approaching or on the contrary, aircraft whose approach to an obstacle presents a real danger are given the free overflight.

The systems described in the international application WO2004 / 025600 (page 14 line 11 to page 15 line 3) and in the French application FR2830360 (page 1 line 33 to page 2 line 19) have such drawbacks in particular.

The object of the invention is in particular to offer a generic solution to anti-collision problems with all types of ground obstacles, whatever their dimensions. For this purpose, the subject of the invention is a method of changing the prohibited zones to an aircraft. It comprises a phase of definition of the geometry of the zones with restricted access and their conditions of access which depend on the aircraft, a phase of characterization of the the aircraft with respect to the conditions of access to the zones and a phase of determining the zones to which the aircraft does not have access.

Advantageously, access to the zones can be conditioned by the type of aircraft or its operational flight situation.

The invention also relates to a system for changing prohibited areas to an aircraft. It comprises means for storing the restricted access zones described by their geometry and their access conditions which depend on the aircraft, a module for characterizing the aircraft with respect to the conditions of access to the zones and a determination module. areas to which the aircraft does not have access.

Advantageously, access to the zones can be conditioned by the type of aircraft or its operational flight situation.

Prohibited zones may be provided to a flight system raising an audible or visual alert when a prohibited zone is going to be penetrated or to an autopilot system making it impossible for the aircraft to enter these areas.

The main advantages of the invention are that it offers a great deal of flexibility since it is adaptable to all types of aircraft, allowing, for example, the fitting of protection zones of an obstacle according to the type of aircraft to which they address themselves. This flexibility makes the invention an excellent basis for defining a new standard of shareable areas for the entire aviation community, be it civilian, military, commercial or recreational, and well beyond the scope of the protection of ground obstacles. It allows a dynamic update of the prohibited areas to an aircraft according to the evolution of its operational situation throughout the flight, thus totally breaking with the frozen nature of the old areas. In addition, it is easy to implement on existing embedded systems. In the future, it will even exploit a function currently under study and will be very difficult to use, to take control of the pilot in certain exceptional critical situations. Finally, protecting voluminal obstacles on the ground by areas whose geometry is described in three dimensions is a simple way to take into account the reliefs of the ground.

• la figure 1, par un synoptique les phases successives du procédé selon l'invention ;
• la figure 2, par un synoptique un exemple d'architecture de système TAWS mettant en oeuvre le procédé selon l'invention.

Other characteristics and advantages of the invention will become apparent with the aid of the following description made with reference to appended drawings which represent:

• the figure 1 by a synoptic the successive phases of the method according to the invention;
• the figure 2 , by a block diagram an example of TAWS system architecture implementing the method according to the invention.

The figure 1 illustrates by a synoptic the possible phases of the method according to the invention.

It comprises firstly a first phase 1 of defining the geometry of the restricted access zones and their access conditions which depend on the aircraft. The first step is to describe portions of the airspace, each in the form of a list of points in latitude, longitude and height above the terrain. The list of points in latitude and longitude determines a two-dimensional polygon, the height above the relief determines a three-dimensional area, whose base is the previously defined polygon, sheet-shaped area of varying thickness over the relief. The second step is to establish criteria to be met by aircraft to be allowed to enter the zones. Advantageously, it may be envisaged to give access to an area only to certain types of aircraft, depending on their performance and their maneuverability, for example. It may be envisaged to allow access to an area only to aircraft that do not exhibit symptoms of failure or failure of safety equipment. It may be considered further to authorize access to an area only to aircraft that have not given any indication that the flight could be hijacked, for example having never issued the code "Hijacked" with their transponder during the flight.

This way of describing areas with restricted access brings a lot of flexibility. It makes it possible to fit them into each other and thus to adapt the safety distance to the type aircraft. For example, a set of skyscrapers can be included in a first area accessible to any aircraft, regardless of its type. This area, which is forbidden to any aircraft, can itself be included in a second, larger area accessible only to helicopters. This area accessible to helicopters can itself be included in a third area larger still and accessible only to helicopters and light aircraft.

Thus, airliners are denied access to the third zone, far from the skyscrapers, this area can be penetrated only by light aircraft and helicopters. Then, the light planes are forbidden access to the second zone, at average distance from the skyscrapers, this zone being able to be penetrated only by the helicopters. Finally, helicopters are denied access to the first zone, close to skyscrapers, this area can not be penetrated by any aircraft.

The method according to the invention also comprises a phase 2 characterizing the aircraft with respect to the conditions of access to the zones. For each of the criteria to be met by an aircraft to be authorized to enter an area, it is a question of determining the condition of the aircraft with respect to this criterion. Advantageously, this can consist of the flight crew to declare any particular operational situation, such as declaring the failure reports or setting their transponder on the "hijacked" code as soon as they suspect an imminent diversion. Or it may be for the ground control personnel to designate any aircraft with suspicious behavior from the ground, for example, radio silence, where the ground systems send this suspicion information to the on-board systems via an existing wireless data link. . All this introduces a real dynamic. Indeed, by taking the previous example of the three nested zones, it can be envisaged a fourth zone encompassing even more largely the third zone and which is accessible only to aircraft showing no symptoms of failure or showing any sign of diversion possible. Thus, an aircraft that normally can approach skyscrapers up to the third zone, the second zone, or even the first zone depending on its type, can be seen dynamically assign during the flight a safe distance from much larger skyscrapers, following a report of failure or suspicion of diversion.

The method according to the invention finally comprises a phase 3 of determining the areas to which the aircraft does not have access. It is, on characterization of an aircraft with respect to the conditions of access to the zones, to update the access authorizations of the aircraft to each zone. In the extreme case of diversion, it can be imagined that the airspace is divided into restricted areas so as to no longer authorize a hijacked flight in particular areas, for example already existing military zones. Indeed the military zones have a very low density of population and almost no air traffic outside the military maneuvers. They therefore have all the security conditions required to handle this situation as serenely as possible. And at the same time, non-military areas are prohibited from diverted flights. In this case it is also desirable to couple the system of avoidance of the planet, whether it is a TAWS or other system, to the autopilot system so that it takes the authority of the pilot, which will be very soon possible. Based on the new no-fly zones or authorized hijacked aircraft, the autopilot system can easily prevent the aircraft from entering prohibited areas protecting human infrastructure and direct the aircraft to a secure military area. But we can also consider other situations in which the autopilot system takes control of the pilot over the restricted areas of the invention. For example, again using the example of the three zones encompassing the building complex, autopilot could prevent the aircraft from overriding the prohibition to enter the third zone. In this case the handling of the device may be preceded by an alert and then a notification to the pilot by the "Flight Warning Computer", which will be called FWC later, which is a system dedicated to lifting alerts. Indeed, hijackers with a good knowledge of the control procedures could seize a device without any external sign being given. So even if they are not directed to an area immediately military security, at least they can not approach human infrastructure with a high population density. It thus becomes technically impossible to approach potential targets for a terrorist attack with an aircraft that the size makes likely to cause significant damage if used as a projectile.

The figure 2 illustrates by a block diagram an exemplary TAWS system architecture implementing the method according to the invention.

It includes a database of restricted areas which describes each zone in terms of geographical location at latitudes, longitudes and height above the terrain, and in terms of access conditions depending on the aircraft. Ideally, the description of these zones can follow a standard recognized by the various actors of the aeronautics, whether civil or military. Ideally also, authorized distributors can provide up-to-date versions of these standardized zone databases, depending on the builds and demolitions of MMS.

The exemplary TAWS system according to the invention also comprises a function 21 for determining the prohibited zones. This function first makes a request for zones to the database 20, at takeoff, for example, to have the generic division of the airspace into restricted zones. Then from the aircraft-specific data known by a database 26 for example, advantageously the aircraft type, this function 21 determines a first list of areas prohibited to the aircraft in particular and in which the latter It is not allowed to penetrate, this as soon as it takes off. Then, each time it receives a message that can modify this list, the function 21 reconsiders the prohibited zones to the aircraft taking into account the new situation. Advantageously, it can receive any message indicating an exceptional operational situation. For example, it may be a failure report of the "Built-in Test Equipment" type, which will be called a BITE report later, issued by a "Line Replaceable Unit" 24 providing a safety function, which is will call LRU later. The LRU are hardware and software modules in drawers such as computers, sensors or actuators, easily replaceable if necessary. They have a function of maintenance of a type known by its Anglo-Saxon designation BITE function. This BITE function allows LRUs to perform diagnostics on their internal operating state and issue reports that are called by extension BITE reports. For example, the function 21 may receive trouble reports entered manually on a "Multipurpose Control Display Unit" 22, which will be called MCDU thereafter. An MCDU is an integrated screen and keyboard device quite common in avionics. Its main characteristic is to offer very generic services for displaying and entering alphanumeric characters. Thus it is easily adaptable to various new applications and in particular to the implementation of the invention, for example the introduction of failure reports when they are not the object of an automatic diagnosis of the BITE report type issued by an LRU. For example finally the function 21 can receive all the codes sent by the transponder 23 or other equipment, in order to identify the possible transmission of the code "hijacked", even if it is very brief. All these messages reflect an event likely to modify the zones specifically prohibited to the aircraft.

The function 21 for example sends the prohibited zones to a display module of the type of a "Terrain Hazard Display" 25, which is a standard graphic display device in avionics offering two-dimensional zone visualization functions. Thus the pilot is informed graphically and in real time of the areas he must avoid. Advantageously, the function 21 also sends the prohibited zones to another sub-function 29 of the TAWS which, knowing the position of the apparatus permanently, is able to raise sound alerts when a prohibited zone is about to be penetrated. through a FWC 30 and an "Aircraft Audio System" 28, which is a standard avionics sound emission device. Advantageously again, the function 21 sends the prohibited zones to another sub-function 31 of the TAWS which, also constantly knowing the position of the apparatus, proposes avoidance trajectories when a forbidden zone is penetrated. It sends the avoidance trajectories to a flight system 27 which may for example have an autopilot function. The autopilot function may, under certain extreme conditions and when the zones authorized to the aircraft are limited to military zones for example, take the authority of the pilot to direct the aircraft in one of the areas in question.

The embodiment of the device described above is part of a TAWS system. But it must be understood that any avoidance system of the planet can implement the method according to the invention.

Claims (12)

1. A method for dynamically updating areas prohibited to an aircraft in flight, comprising:

   - a phase for defining the geometry of the restricted access areas and their access conditions, which depend on the aircraft (1);

   the method being characterised in that it comprises:

   - a phase for characterising the status of the aircraft relative to the conditions of access to the areas (2);

   - a phase for determining the areas to which the aircraft does not have access (3);

   the phase for characterising the status of the aircraft and the phase for determining the areas to which the aircraft does not have access being triggered as soon as an event is likely to modify the status of the aircraft with regard to the conditions for accessing an area.
2. The method for dynamically updating areas prohibited to an aircraft according to claim 1, characterised in that access to the areas depends on the type of aircraft.
3. The method for dynamically updating areas prohibited to an aircraft according to claim 1 or 2, characterised in that access to the areas depends on the performance levels or the manoeuvrability of the aircraft.
4. The method for dynamically updating areas prohibited to an aircraft according to claim 1, 2 or 3, characterised in that access to the areas depends on the operational flight situation of the aircraft.
5. The method for dynamically updating areas prohibited to an aircraft according to claim 1, 2, 3 or 4, characterised in that access to the areas depends on the emission with the transponder of the hijack code.
6. The method for dynamically updating areas prohibited to an aircraft according to claim 1, 2, 3, 4 or 5, characterised in that obstacles on the ground are included in a first area that is not accessible to any aircraft, said first area in turn being included in a second area that is only accessible to helicopters, said second area in turn being included in a third area that is only accessible to light aircraft, said third area in turn being included in a fourth area that is only accessible to aircraft that do not show any signs of fault or hijacking.
7. A system on board an aircraft for dynamically updating areas prohibited to an aircraft, comprising:

   - a means for storing restricted access areas (20) that are described by their geometry and their access conditions, which depend on the aircraft;

   the system being characterised in that it comprises:

   - a module for characterising the status of the aircraft (22, 23, 24) relative to the conditions of access to the areas;

   - a module for determining the areas to which the aircraft does not have access (21);

   the module for characterising the status of the aircraft and the module for determining the areas to which the aircraft does not have access being activated as soon as an event is likely to modify the status of the aircraft with regard to the conditions for accessing an area.
8. The system for dynamically updating areas prohibited to an aircraft according to claim 7, characterised in that access to the areas depends on the type of aircraft.
9. The system for dynamically updating areas prohibited to an aircraft according to claim 7 or 8, characterised in that access to the areas depends on the performance or the manoeuvrability of the aircraft.
10. The system for dynamically updating areas prohibited to an aircraft according to claim 7, 8 or 9, characterised in that access to the areas depends on the operational flight situation of the aircraft.
11. The system for dynamically updating areas prohibited to an aircraft according to claim 7, 8, 9 or 10, characterised in that it comprises a flight system (29) raising an audible or visual alert when a prohibited area is entered.
12. The system for dynamically updating areas prohibited to an aircraft according to claim 7, 8, 9, 10 or 11, characterised in that it comprises a flight system (27) preventing entrance into a prohibited area by taking control of the aircraft.

Images