FR2947640A1 - Method for detecting surrounding aircraft with respect to reference aircraft, during flying, involves displaying information delivered by scanning of antenna on display screen of aircraft for indicating surrounding aircraft - Google Patents

Abstract

The method involves defining a scanning volume (7) centered on a path defined along a flying plane of a reference airplane (1), from a mobile antenna (4) of a weather radar (3), to detect the surrounding aircraft for being placed in the scanned volume. Information delivered by scanning of the antenna is displayed on a display screen (5) of an aircraft for indicating surrounding aircraft. A scanning angular sector is located in a vertical plane.

Description

The present invention relates to a method for detecting surrounding aircraft relative to a reference aircraft in flight. Given the constant and significant increase in air traffic over the past decades, very precise regulations have been defined and are still today at the international level to ensure the regulation of air navigation in an optimal and safe manner. Thus, to detect aircraft, such as civil transport aircraft while in flight and to avoid conflict between two aircraft, including, but not limited to, ground radar facilities, beacons and collision-avoidance systems (TCAS) mounted on board the aircraft, so as to inform the pilot and co-pilot of a first aircraft of the approach or of the presence of a second aircraft as soon as possible. in a predetermined safety zone of the first aircraft so as to take the necessary decisions and measures in the event of a real risk of conflict. While performing satisfactorily, ground-based radar facilities are limited in scope, so that when aircraft are in oceanic areas, for example, they are no longer in contact with them and are not surrounding traffic. For example, if an airplane has changed its flight plan for any reason, it may conflict with another plane on a nearby flight plan. In this case, the TCAS anti-collision systems of the two aircraft communicate with each other by their respective transponders to alert the pilots of the aircraft concerned of a conflict situation, which pilots then modify the trajectory of their aircraft so as to move them away. one of the other. However, such transponder anti-collision systems are only effective if the two conflicting aircraft are equipped with them. In addition, it is known that military aircraft have an on-board radar specially designed to detect devices (friends or enemies) so as to hook the target and thus follow the detected aircraft. This embedded radar can be independent or integrated into the weather radar equipment. The object of the present invention is to propose a method for detecting surrounding aircraft relative to a reference aircraft in flight, making it possible to further secure flights of aircraft on all of them. For this purpose, the method for detecting surrounding aircraft with respect to a reference aircraft in flight which is equipped with a weather radar and a flight management system incorporating the flight plan of said reference aircraft is remarkable, according to the invention, in that it consists, from the mobile antenna of said weather radar, to define a scanning volume centered on the trajectory defined according to said flight plan of the reference aircraft to detect said surrounding aircraft 20 likely to be in said scanned volume, and to display the detection in-formations delivered by the scans of the antenna of said radar, on a display screen of said aircraft to indicate said surrounding aircraft. Thus, thanks to the invention, by the correlation between the use of the meteorological radar as a detection system of the surrounding aircraft and that of the flight plan of the reference aircraft on which the volume swept by said radar is wedged. permanent surveillance and detection of the airspace used by the reference aircraft is obtained on the entire flight. The method according to the invention thus comes in 294.7640. complement existing detection systems, which further secures the flight of aircraft and reassures pilots, especially during transoceanic flight phases or other in which ground radar facilities are inoperative. The method according to the invention thus allows a safe and reliable detection of any surrounding aircraft entering the detection zone swept by its weather radar even if, moreover, the surrounding aircraft is not equipped with an anti-aircraft system. collision. For example, said scanning volume is determined from the displacement of the given angle-transmitting cone of said mobile radar antenna in parallel and alternating bands to cover the whole of said scanning volume, according to first and second perpendicular angular sectors from said antenna and centered on the trajectory of said flight plan of the reference aircraft. Thus, in addition to a reliable and reliable detection of the aircraft in the reference aircraft environment, the scanning volume is limited to an airspace defined by said perpendicular angular sectors, centered on the trajectory of the plane. flight, which avoids excessive and unnecessary sweeping of the antenna. Preferably, said first scan angular sector is in a vertical plane and is defined by the desired detection distance from said reference aircraft and by the desired scan height with respect to the flight path of said flight plan, and said second The scanning angular sector is horizontal, perpendicular to said first scanning sector, and is defined from an azimuth axis located on said flight plan and a scanning width centered on said azimuth axis. By these different parameters, the angular sectors, and therefore the sweep volume, can be adapted to the flight conditions (cruise, approach, speed ...) and modified accordingly.

Advantageously, the settings of said angular sectors defining said scanning volume are automated based on the flight plan of said reference aircraft. Preferably, said detection information delivered by the successive sweeps of the mobile cone is displayed on the navigation screen of said reference aircraft indicating the information relating to the flight plan of said aircraft. Thus, it is then possible to alternate the display of said detection information of the surrounding aircraft on said display screen with at least 1 o the display of information relating to the meteorological conditions to come, detected by the radar. This is particularly interesting when said aircraft is in cruise flight. The display can also be done sequentially or superimposed. When the aircraft is in the approach phase, it is advantageous to alternate the display of said surrounding aircraft detection information and weather conditions on said display screen with the display of the wind shear information. According to an exemplary representation, the horizontal positions of said surrounding aircraft detected on said display screen are displayed by a geometrical symbol and in this displayed geometrical symbol information relating to the relative height and radial velocity of said surrounding aircraft is included. detected relative to those of said reference aircraft. The drawing figures will make it clear how the invention can be realized. In these figures, identical references designate similar elements. FIGS. 1 and 2 are schematic views in respective vertical and horizontal planes, showing the definition of an example of a scanning volume for detecting surrounding aircraft, from the meteorological radar of a reference aircraft, and centered on the trajectory of the flight plan of this one. FIG. 3 shows in perspective the volume swept by the emission cone 5 of said radar. FIG. 4 schematically shows the implementation of the detection method of the invention from the reference aircraft. FIGS. 5 and 6 respectively show an example of swept volume when said reference aircraft is in cruise flight and the display of the surrounding aircraft detected on the navigation screen of the aircraft. Figures 7 and 8 are similar to previous Figures 5 and 6 but show the volume swept when the aircraft is in the approach phase. FIGS. 9 and 10 are respectively examples of sequences of the different pieces of information that may be displayed, depending on the choice of pi-lotes, on the navigation screens of said aircraft, when it is in cruising flight and in phase of approach. The implementation of the detection method according to the invention is carried out, as shown schematically in FIG. 4, from the flight management system 2 of the reference transport aircraft 1, the weather radar 3 with antenna mobile 4 and a display screen 5 such as the navigation screen of the aircraft 1. In particular, the flight management system 2 includes in particular the data of the flight plan of the aircraft 1 introduced prior to take-off of the latter and defining the trajectory T or the route to be followed by beacons, waypoints, etc. This flight plan may be modified during the flight by the pilot if this proves necessary, following a technical failure or an external order, for example. The weather radar 2.947640 3, located in the nose 6 of the aircraft, detects, according to the operating modes chosen, the general weather conditions, the wind shear, etc .: and, according to the invention, the surrounding planes likely to be in its scanning volume 7 as will be seen below. And the navigation screen 5 displays information relating to flight plan, weather conditions, wind shear, surrounding aircraft, etc., depending on the display mode chosen. Two navigation screens 5 are generally provided in the cockpit (not shown) of the aircraft, one dedicated to the pilot, the other to the co-pilot, and each of them can choose the type of display according to the concerns of the moment. and can thus have several images relating to the different information displayed sequentially or superimposed on its screen, as will be seen later. The flight management system 2 is connected to the weather radar 3 by a link 10 through which the data relating to the flight plan of the aircraft circulates. The radar 3 and its antenna 4 communicate with each other via respective transmission and reception links 11 and are furthermore connected to the screen or to the navigation screens 5 by a link 12 transmitting both for display on the latter. , the information relating to the different modes of operation of the radar. As can be seen in FIGS. 1 and 2, from the mobile antenna 4 of the weather radar, a scanning volume 7 centered on the trajectory T defined by the plane of reference is defined in front of the nose 6 of the reference plane 1. flight of the aircraft 1, and the detection information detected by the scans of the antenna 4 on the screen or on the navigation screens 5 is displayed via the link 12 to indicate, if There are some, the surrounding planes being in said swept volume 7. This latter is described by the emission or scanning cone C coming from the mobile antenna 4 of the radar and is represented in two perpendicular planes one on the other, namely, in a figure 1, the vertical longitudinal plane of symmetry of the aircraft and, in Figure 2, the horizontal plane thereof. It can be seen, in the example of FIG. 1, that the aircraft 1 is in the cruising flight phase, the trajectory T of its flight plane reported in this vertical plane being horizontal. In the latter, the emission cone C of the radar, the apex of which comes from the antenna 4, will describe a first angular sector of aim S1 centered on the trajectory T. We have represented the median geometric axis CA of this cone C, which is moved in FIG. 1 from the high position to the low position, thereby describing parallel and alternating strips B, as will be seen in FIG. 3. For example, the transmit or scan cone C of the radar 3 can form an angle CN of 3 ° to 5 °, whereas the angular sector of sight S1 (in the vertical plane) is about 30 ° (15 ° of the angle 15 °). and other of the trajectory T of the flight plan). These values can obviously vary and be adjusted according to input parameters and flight phases as will be indicated later In the representation of FIG. 2, the second angular sector S2 described by the emission cone C of FIG. Angle CN, perpendicular to the angular sector of sight S1, is also centered on the trajectory T of the flight plan, which, in the horizontal plane illustrated, is angularly offset with respect to the longitudinal axis X of the aircraft shown. The trajectory T of the latter is directed to the right by making, for example, an angle of 30 ° with respect to the longitudinal axis X or the vertical longitudinal plane of symmetry of the aircraft. The emission or scanning cone C of the antenna 4 of the radar 3 describes in this plane the above angular sector S2, that is to say having its median geometric axis CA which moves from left to right then from right to left between the two limits of the horizontal angular sector S2 and respectively on either side of the trajectory T. The angular value of this sector is, for example, 30.degree. flight phases to consider. The input parameters for the adjustment in the vertical longitudinal plane of symmetry (FIG. 1) relate to the angle of view, that is to say the desired angular sector S1, which is deduced from the amplitude sought for the distance D of detection (range of the radar) which can go up to a thousand kilometers and for the height of the sweep E determined by an elevation on both sides of an average elevation or according to the flight plan by ground ratio 9. 0 And the input parameters for the adjustment in the horizontal plane (Figure 2) perpendicular to the vertical plane of symmetry, concern the left-right scanning angle, that is to say the angular sector S2, as well as the geometric scanning center of this angular sector, that is to say the center of azimuth CZ located on the trajectory T of the flight plan and offset, in this example, angularly from the axis XX. To these settings are added, among others, the situation of the reference aircraft 1 according to whether it is in cruise flight, approach phase, etc., its speed, etc. Thanks to these adjustments, the scanned or scanned volume 7 is defined by the antenna 4 of the radar 3 and the latter then delivers on the navigation screens 5, if surrounding planes are detected in the volume, the horizontal two-dimensional position of these last relative to the reference aircraft, the relative height relative to the reference aircraft and the radial velocity relative thereto. Other indications could also be made. The settings of these and other parameters are made automatically by the flight management system 2 according to the flight plan of the aircraft 1, so that they are carried out in real time and / or in a predictive manner. The radar thus settles on the information transmitted by the system 2 ensuring a scanning volume centered on the trajectory of the flight plan. The flight plan makes it possible, from the trajectory T, to determine the geometric scanning center (azimuth center located on the trajectory of the flight plan), the width of the horizontal scan by a predefined value of the scanning sector or flight plan function, the amplitude (elevation) of the sweep and the amplitude in distance (range) based on the flight parameters (speed ...). From all these parameters and their adjustments according to the flight plan, the scanning volume 7 is defined as that illustrated in FIG. 3 by way of example. We see in particular the parallel bands B described successively forming in fact a single band B in zigzag, after each horizontal scanning sector, to the right then to the left, by the emission cone of the radar, with, after each band, a vertical displacement of the cone, so as to scan the entire volume 7 having as a center the trajectory T of the flight plan of the reference plane 1. Thus, thanks to the link between the radar 3 and the flight plan, the cone of emission C of the mobile antenna 4 scans only the desired useful area of the flight plan and does not look elsewhere, so that it avoids a loss of time and that is scanned more often the area concerned. In the example of Figure 2, it is useless to scan left of the X axis while the plane turns right. The volume 7 defined by these parameters is scanned by the cone C of the antenna 4 of the radar and tracks in real time the flight plan of the reference aircraft 1, which ensures the surveillance of this airspace or volume volume. green by the radar 3 and thus the detection of surrounding aircraft, thus anticipating possible conflicting risks. For example, the duration of the race of a scan is of the order of five seconds, so that a total of about twenty-five seconds is necessary to cover the volume in question.

Thus, the method allows a safe and reliable detection of surrounding aircraft in the airspace delimited by the sweeping volume of the radar, centered on the trajectory of the flight plan, while preventing the radar from scanning a too far apart space and / or away from the trajectory of the flight plan and therefore unnecessary, which would result in a waste of time. FIG. 5 schematically shows a first example of detection of surrounding aircraft when the reference plane 1, emitting the scanning volume 7 centered on the trajectory T of the flight plan, is in cruise flight at a given level, according to the trajectory T, ho horizontal in this example. This is particularly the case during a transatlantic trip based on an established great circle (the shortest route between two points on Earth). Note that, in the scanning volume 7 defining an airspace of safety, are three surrounding aircraft A1, A2 and A3 (it is specified, of course, that the scale of representation of Figure 5 is not that in the reality, the distance separating the aircraft being hundreds of miles). The reconciliation between two following aircraft can occur through changes in speed or even changes in flight level, which is common because the aircraft have flight levels optimized for their consumption, but which constantly evolve to me- sure that their masses decrease because of the consumption of kerosene. The method according to the invention makes it possible to anticipate these conflicting situations by adapting, if necessary, the trajectory and the speed of the aircraft. In the present case, the three aircraft marked by the radar (two, Al and A2 going in the same direction as the reference aircraft 1, with one A2 of the two located substantially on the same flight level, the third A3 moving in the opposite direction) are then displayed on the navigation screens 5 such as that shown in FIG. 6. On this screen 5, the reference airplane 1 is shown symbolized with the straight trajectory T of its flight plan according to FIG. the desired course.

And, on this trajectory, is the surrounding plane A2 symbolized by a rectangle R or any other possible sign, with the indication 300 signifying the flight level (identical to the reference plane) and +5 its radial speed in knots relative to the reference plane 1. The pilot of the latter, informed and visualizing this aircraft environ- nant on its screen, will adapt if necessary its trajectory and / or its speed. We also see the position, symbolized by rectangles R, of the two other surrounding aircraft Al and A3 detected on the screen 5 with two-dimensional positions offset from the trajectory T followed by the reference aircraft and their flight levels and radial velocities respectively.

It is advantageous to envisage an interlacing of the display modes on the screen or on the navigation screens 5. Thus, as shown in FIG. 9, one of the navigation screens, depending on the driver's choice, may, for example, for example, display a representative image 5A of the meteorological information detected by the radar, then a representative image 5B of the information of the scanned detection volume 7 in the flight plan of the aircraft and so on. These images of these modes and images of other modes can be displayed successively as in Figure 9 or superimposed. FIG. 7 is a schematic representation of a second example of detection of surrounding aircraft when the reference aircraft 1 is in the approach phase with respect to the ground 9. The scanned detection volume 7 delivered by the antenna 4 radar 3 is centered on the trajectory T of the flight plan and note that the volume swept is narrower for landing. The implementation of the method of the invention is particularly interesting when approaching planes that follow predefined trajectories. Thus, the method makes it possible to ensure that the preceding plane surrounding and detected A4 does not tend to approach via its position and its radial speed displayed on the navigation screen 5 of FIG. there is no incursion on the runway 14 and no plane crosses the approach axis. In the volume swept 7 by the radar is detected the surrounding aircraft A4 which is displayed on the navigation screen 5 in the form of a rectangle R located on the trajectory T of the reference plane 1 and a target - 500 feet study with a relative radial speed of -5 knots compared to the reference aircraft. The driver of the latter can follow and evolution of the A4 aircraft and take appropriate measures if necessary. Another aircraft A5 is already placed on the runway 14. Here too, it is advantageous to consider an interlacing of the display modes on the navigation screen 5. And, as the aircraft 1 is in the approach phase, by For example, at a level less than 2000 feet, it is possible to integrate the mode of operation of the radar 3 relating to wind shear in addition to those relating to FIG. 9. In this way, a sequence can be displayed on the screen. of images such as that illustrated in Figure 10, namely a 5A image representative of future meteorological conditions; a representative 5C image of the wind shear; a representative image 5B of the flight plan; again, a representative 5C image of the wind shear and then repeat the sequence with the representative image 5A of the meteorological conditions. As before, the display can be successive, as here, or superimposed.

The method of the invention therefore provides additional security in the various phases of flight of the aircraft, particularly in the approach phase, thus reducing the workload of the crew that can indulge in other tasks.

In addition, by increasing the reliability and redundancy of the various methods and / or detection systems, it is thus possible to increase the density of the traffic, that is to say the number of aircraft in a given airspace. Note also that the method of the invention is completely autonomous and requires no transmission between the two conflicting aircraft, which allows a better awareness of crew potential danger and the detection of aircraft not equipped with transponders or transponders failing.

Claims (8)

REVENDICATIONS1. A method for detecting surrounding aircraft relative to a reference aircraft in flight which is equipped with a weather radar (3) and a flight management system (2) integrating the flight plan of said reference aircraft, characterized in that it consists, from the mobile antenna (4) of said weather radar, in defining a scanning volume (7) centered on the trajectory (T) defined according to said flight plan of the reference aircraft to detect said surrounding aircraft likely to be in said 1 o swept volume and to display the information provided by the scans of the antenna of said radar, on a display screen (5) of said aircraft to indicate said surrounding aircraft. 2. Method according to claim 1, characterized in that said scanning volume (7) is determined from the displacement of the given angle emission cone (C) of said mobile antenna (4) of the radar, in parallel and alternating bands (B) for covering the whole of said scanning volume, according to first and second perpendicular angular sectors (Si, S2), originating from said antenna and centered on the trajectory (T) of said flight plan of the reference aircraft. 20 3. Method according to claim 2, characterized in that said first scanning angular sector (Si) lies in a vertical plane and is defined by the desired detection distance from said reference aircraft and by the desired scanning height relative to to the trajectory of said flight plane, and in that said second scanning angular sector (S2) is horizontal, perpendicular to said first scanning sector, and is defined from an azimuth axis located in said plane of flight and a scanning width centered on said azimuth axis. 4. Method according to one of claims 2 or 3, characterized in that one automates the settings of said angular sectors (Si, S2) defining said scanning volume (7) based on the flight plan of said aircraft. reference. 5 5. Method according to one of claims 1 to 4, characterized in that one displays said detection information delivered by the sweeps of the moving cone (C) on the navigation screen (5) of said reference aircraft indicating the information relating to the flight plan of said aircraft. 0 6. Method according to one of claims 1 to 5, characterized in that it alternates the display of said detection information of the surrounding aircraft on said display screen (5) with at least information relating to the weather conditions to come detected by the radar. 15 7. Method according to claim 6, characterized in that the display of said detection information of the surrounding aircraft and weather conditions on said display screen is alternated with those relating to wind shear, 8. Method according to any one of the preceding claims 1 to 7, characterized in that the horizontal positions of said detected surrounding aircraft (A1, A2,...) Are represented on said display screen (5) by a geometric symbol and in that included in this displayed geometric symbol, at least information regarding the relative height and radial velocity of said detected surrounding aircraft relative to those of said reference aircraft.