Abstract:
A device for assisting in the piloting of an aircraft includes a detecting device for detecting all the aircraft in the vicinity and a display device for presenting, on a display screen illustrating a vertical plane, characteristic symbols indicating the positions of these aircraft in the vicinity.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method and device for assisting in the piloting of an aircraft, in particular a military or civilian transport airplane. 
     BACKGROUND OF THE RELATED ART 
     Normally, the traffic surrounding an aircraft is represented onboard that aircraft on a display screen that, more often than not, indicates a position in plan mode, of the PPI (Plan Position Indicator) type, illustrating a graphical representation in the horizontal plane of the aeronautical surroundings of the aircraft. Such a display mode enables the pilot of the aircraft to easily identify the bearing and the distance of the aircraft in the vicinity displayed, but, however, not their vertical position. Also, to overcome this oversight, there are also normally displayed numerical values (relative or absolute) indicating the altitudes of the various aircraft in the vicinity. However, such a numerical representation of the altitude (or vertical position), associated with the abovementioned graphical representation (which is far more intuitive) of the horizontal position, makes understanding and perceiving the real position of the various aircraft in the vicinity difficult for the pilot. This display mode involves in particular a significant workload and a significant time to enable the pilot to mentally integrate the actual situation of the air environment of his aircraft. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a method for assisting in the piloting of an aircraft, in particular a transport airplane, which can be used to remedy the abovementioned drawbacks. 
     To this end, said method whereby there is presented, on at least one display screen of said aircraft, a set of information that illustrates a vertical plane and that comprises:
         a system of axes, of which a Y axis is graduated altitude-wise, and an X axis is graduated distance-wise from the position of the aircraft; and   a characteristic symbol representing the aircraft, which is positioned on said Y axis, in a position representative of the altitude of said aircraft, and
 
is noteworthy in that, during a flight of the aircraft:
       a) automatic surveillance of the surroundings of said aircraft is carried out, so as to be able to detect all aircraft in the vicinity that are located in a particular detection space situated at least in front of said aircraft; and   b) for each of the aircraft in the vicinity detected in the step a), the following successive series of operations is performed automatically:
       b1) distance and altitude information concerning the aircraft in the vicinity is generated;   b2) this distance and altitude information is used to determine a distance value and an altitude value; and   b3) there is displayed, on said display screen, an auxiliary characteristic symbol that represents said aircraft in the vicinity and that is positioned on said system of axes in a position corresponding:
           on said Y axis, to said altitude value; and   on said X axis, to said distance value.   
           
       

     Thus, with the invention, the pilot of the aircraft is supplied with a graphical representation that provides him with a readily understandable and legible display of the actual situation of his surroundings, in particular in the vertical plane, since each auxiliary characteristic symbol representing one of the aircraft in the vicinity detected is located on the Y axis (namely the vertical scale) at the corresponding altitude value (that is, at its actual altitude, absolute or relative, as specified below). This graphical representation of the vertical plane is far more intuitive for the pilot than a normal numerical representation of the altitude. 
     The method of assistance according to the invention also makes it possible to inform the pilot on the distance (distance value on the X axis) of the various aircraft in the vicinity. 
     Consequently, the method according to the invention enables the pilot to improve his perception of the actual situation of the surroundings of his aircraft, and makes it possible to reduce his workload, by significantly reducing the time it takes to understand the surrounding traffic. 
     Advantageously, in the step b1), distance and altitude information relating to at least one of said aircraft in the vicinity is generated:
         using a radar detection applied from said aircraft; or   using the detection on the aircraft of a response from said aircraft in the vicinity to a prior interrogation sent from said aircraft; or   using the reception on the aircraft of information that is transmitted by said aircraft in the vicinity.       

     Furthermore, advantageously, in the step b2), the distance between the actual position of the aircraft and an auxiliary position linked to said aircraft in the vicinity is determined as a distance value for at least one aircraft in the vicinity. In this case, said auxiliary position corresponds, advantageously;
         simply to the actual position of the aircraft in the vicinity; or   to the orthogonal projection of that actual position of the aircraft in the vicinity on the axis of said aircraft; or   to the orthogonal projection of said actual position of the aircraft in the vicinity on a segment of the flight path of the aircraft, and namely on that which is the nearest to this actual position.       

     Moreover, the method according to the present invention can present numerous other advantageous features. In particular:
         different distance values of aircraft in the vicinity can be highlighted, on the display screen, by different symbol systems; and/or   the presentation characteristics of said set of information can depend on at least one particular parameter such as the flight phase of the aircraft for example; and/or   said Y axis of said system of axes can have a variable scale; and/or   at least one auxiliary characteristic symbol presented on said display screen can be interactive.       

     Furthermore, in a particular embodiment, the following operations are also carried out:
         for at least one aircraft in the vicinity detected in the step a), its flight path angle is determined; and   in the step b3), there is also displayed, on the display screen, in association with the auxiliary characteristic symbol representing that aircraft in the vicinity, a straight-line segment illustrating its flight path angle.       

     The above operations can also be carried out for the aircraft on which the present invention is implemented. 
     Moreover, in a preferred embodiment, said display screen comprises at least two display windows, of which a first window comprises said set of information (abovementioned, illustrating the vertical plane) and a second window comprises a set of additional information, of the usual type, that illustrates a horizontal plane and that comprises:
         a system of axes graduated distance-wise and bearing-wise;   a characteristic symbol illustrating the aircraft; and   auxiliary characteristic symbols illustrating the aircraft in the vicinity that have been detected.       

     Thus, by associating with the graphical representation in the vertical plane according to the invention, a graphical representation in the horizontal plane of the usual type, the pilot can improve his perception of the actual situation of his environment, since the representation in the horizontal plane particularly provides additional information relating to the bearings of the aircraft in the vicinity. 
     The present invention also relates to a device for assisting in the piloting of an aircraft, in particular a transport airplane. 
     According to the invention, said device of the type comprising display means that can present, on at least one display screen of said aircraft, a set of information that illustrates a vertical plane and that comprises:
         a system of axes, of which a Y axis is graduated altitude-wise, and an X axis is graduated distance-wise from the position of the aircraft; and   a characteristic symbol representing the aircraft, which is positioned on said Y axis in a position representative of the altitude of said aircraft,
 
is noteworthy in that:
   said device also comprises:
           first means for performing an automatic surveillance of the surroundings of said aircraft so as to be able to detect all aircraft in the vicinity that are located in a particular detection space situated at least in front of said aircraft;   second means for generating, for each of the aircraft in the vicinity detected by said first means, distance and altitude information; and   third means for determining, for each of said aircraft in the vicinity detected, using said distance and altitude information, a distance value and an altitude value; and   
           said display means are formed so as to present, on said display screen, for each of the aircraft in the vicinity detected by said first means, an auxiliary characteristic symbol that represents the aircraft in the vicinity concerned and that is positioned on said system of axes in a position corresponding:
           on said Y axis, to the corresponding altitude value; and   on said X axis, to the corresponding distance value.   
               

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The figures of the appended drawing clearly show how the invention can be implemented. In these figures, identical references denote similar elements. 
         FIG. 1  is the block diagram of an assistance device according to the invention. 
         FIG. 2  shows schematically a display window of an assistance device according to the invention, clearly highlighting the main characteristics of the present invention. 
         FIG. 3  illustrates schematically a particular display screen of an assistance device according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The device  1  according to the invention and represented schematically in  FIG. 1 , is intended to assist operators (pilot, copilot, etc.) of an aircraft, not shown, for example a military transport airplane, when piloting said aircraft. 
     To do this, said assistance device  1  which is onboard the aircraft, comprises display means  2  which can present, on a display window  3  of a standard display screen  4 , a set of information  5  specified below. Said display window  3  can be represented on a part  6 A of the display screen  4 , for example a bottom part of the latter. It can also be represented over all of said display screen  4 . 
     Said set of information  5  illustrates a vertical plane and comprises, as represented in  FIG. 2 :
         a system of axes SA, of which a Y axis  7  is graduated altitude-wise, preferably expressed in feet (one foot measuring approximately 0.3 meters), and an X axis  8  which is graduated distance-wise from the position of the aircraft illustrated by a characteristic symbol  9 , said distance preferably being expressed in nautical miles NM (one nautical mile being approximately 1852 meters);   said characteristic symbol  9  which represents the aircraft and which is positioned on said Y axis  7  in a position PO representative of the altitude of said aircraft; and, where appropriate   a standard plot T 1 , representing the profile of the terrain being flown over and showing a vertical section  10 . This plot T 1  can be formed according to the current route of the aircraft; and   a standard plot T 2 , located above the plot T 1  and representing a safe altitude.       

     Said device  1  can also comprise a set  12  of information sources, which is linked via a link  13  to said display means  2 . Said set  12  of information sources can, in particular, comprise the following means not described in any more detail:
         a central processing unit for acquiring and processing information, for example a flight management system FMS; and   normal information sources such as navigation instruments and sensors giving information on the state and position of the aircraft, for example.       

     According to the invention, said device  1  further comprises:
         means  14 :
           that make it possible to automatically monitor the surroundings of said aircraft so as to be able to detect all aircraft in the vicinity that are located in a particular detection space located at least in front of said aircraft; and   that comprise incorporated means for generating, for each of the aircraft in the vicinity detected, distance and altitude information specified below; and   
           means  15  that are linked via a link  16  to said means  14  and that are formed so as to determine, for each of the aircraft in the vicinity detected, using distance and altitude information received from said means  14 , a distance value and an altitude value that are transmitted via a link  17  to said display means  2 .       

     Furthermore, according to the invention, said display means  2  are formed to present, on said display window  3  of said display screen  4 , auxiliary characteristic symbols  18 A,  18 B and  18 C that respectively represent the different aircraft in the vicinity detected by the means  14 . According to the invention, each of said auxiliary characteristic symbols  18 A,  18 B and  18 C is positioned on said system of axes SA in a position  19 A,  19 B,  19 C that corresponds:
         on said Y axis  7 , to the corresponding altitude value determined by the means  15 ; and   on said X axis  8 , to the corresponding distance value (specified below), also determined by said means  15 .       

     Thus, the device  1  according to the invention supplies the pilot of the aircraft with a graphical representation that gives him a readily understandable and intuitive presentation of the actual situation of his surroundings, in particular in the vertical plane, since each auxiliary characteristic symbol  18 A,  18 B,  18 C representing one of the aircraft in the vicinity detected is located on the Y axis  7  (namely the vertical scale) at the corresponding altitude value (that is, at its actual altitude, absolute or relative, as specified below). 
     Said device  1  also makes it possible to inform the pilot on the distance (distance value on the X axis  8 ) of the various aircraft in the vicinity. 
     Consequently, the device  1  according to the invention enables the pilot to improve his perception of the actual situation of the surroundings of his aircraft, and makes it possible to reduce his workload, by significantly reducing the time it takes to understand the surrounding traffic. 
     In the context of the present invention, said means  14  intended to generate distance and altitude information for the various aircraft in the vicinity can be implemented according to various embodiments, making it possible to obtain the geographic location of the various aircraft in the vicinity relative to the aircraft equipped with said device  1 . 
     In a first embodiment, said means  14  perform a normal direct, non-cooperative, radar-type detection. The radar that is mounted on the aircraft equipped with the device  1  is able to know the elevation (bearing, distance, elevation) of the various aircraft in the vicinity so as to obtain a relative position for each of said aircraft in the vicinity relative to said aircraft. This embodiment is particularly appropriate in the case where not all the aircraft in the vicinity have a cooperative system as described below. 
     In a second embodiment, said means  14  perform a detection by response to interrogation, relating to a traffic collision avoidance system, TCAS. With such a cooperative system, the aircraft equipped with the device  1  interrogates the aircraft in the vicinity which return information enabling them to be located, in the form of absolute geographic positions. 
     Furthermore, in a third embodiment, said means  14  are formed so as to regularly receive from the aircraft in the vicinity position information making it possible to locate them. The means  14  take account, in this case, of an automatic transmission of surveillance parameters of the ADS-B (Automatic Dependent Surveillance-Broadcast) type. The duly obtained position is also an absolute geographic position. 
     As indicated previously, said means  14  perform a surveillance of the surroundings in a detection space. This detection space can correspond to any space around the aircraft, where said means  14  are technically able to perform a detection. It can also correspond (solely) to the space that can be displayed on the display screen  4 . 
     From the abovementioned information generated by the means  14 , the means  15  are able to determine the altitude values that correspond to the actual altitudes of the various aircraft in the vicinity. The actual altitude of an aircraft in the vicinity is deduced from the vertical position of that aircraft in the vicinity, which is known either in a relative manner (abovementioned first embodiment) or in an absolute manner (abovementioned second and third embodiments). 
     Furthermore, said means  15  determine, as a distance value for an aircraft in the vicinity, the distance between the actual position of the aircraft (equipped with the device  1 ) and an auxiliary position linked to that aircraft in the vicinity. In this case, said auxiliary position corresponds:
         simply and directly to the actual position of the aircraft in the vicinity. Thus, the distance between the characteristic symbol  9  and the corresponding auxiliary characteristic symbol directly illustrates the actual distance between the two aircraft, independent of their directions; or   to the orthogonal projection of that actual position of the aircraft in the vicinity on the axis of said aircraft equipped with the device  1 ; or   to the orthogonal projection of said actual position of the aircraft in the vicinity on a segment S 1 , S 2 , S 3  of the flight path T 0  of the aircraft equipped with the device  1 , and more specifically on the segment that is closest to that actual position, as detailed further below with reference to  FIG. 3 .       

     It will be noted that, in the context of the present invention, different symbol systems can be used to show the distances of the aircraft in the vicinity relative to a planographic plane taken into account. It is possible in particular to use a set of different colors, different broken lines, and variable sizes. 
     Moreover, in the context of the present invention, said display means  2  can be formed so as to implement the following characteristics:
         the modes of presentation of said set of information  5  can depend on at least one particular parameter, for example the flight phase or an altitude stratum (offering a benefit);   the display can also be filtered according to various parameters such as the flight phase, the position of the aircraft in the vicinity relative to the flight plane, etc;   different or variable scales can be applied to the Y axis  7 , in order to improve the accuracy of the information in a given altitude stratum. As an example, in cruising flight, only the levels close to the aircraft equipped with the device  1  can be of interest; and   the various auxiliary characteristic symbols  18 A,  18 B and  18 C can be interactive such that, on pointing and activating a cursor on one of said symbols  18 A,  18 B and  18 C, the display means  2  display information concerning the corresponding aircraft in the vicinity, such as its speed, its altitude, its bearing or data enabling it to be identified.       

     Moreover, in one particular embodiment, said device  1  also comprises means, for example said means  14 , making it possible to provide the flight path angle (FPA) of the aircraft in the vicinity, and of the aircraft on which the device  1  is mounted. This FPA value can be obtained, either by direct transmission (ADS-B), or by trigonometrical calculation on position and altitude variations at two successive instants. The display means  2  are formed so as to present on the window  3  of the display screen  4 , in association with the auxiliary characteristic symbol representing an aircraft in the vicinity or the aircraft equipped with the device  1 , a straight-line segment illustrating the corresponding flight path angle.  FIG. 2  shows such straight-line segments  20 A and  20 B in association with the auxiliary characteristic symbols  18 A and  18 B. 
     Moreover, in a preferred embodiment, the screen  4  is a navigation screen, of the ND (Navigation Display) type, which comprises, in addition to the window  3  located in its bottom part  6 A, a window  22  located in its top part  6 B, as represented in  FIG. 3 . The window  22  comprises a set of information  23  that corresponds to a normal presentation on a navigation screen and illustrates the situation of the aircraft (lateral flight plane) in a horizontal plane. This set of information  23  comprises in particular, as represented in  FIG. 3 :
         a symbol  24  illustrating the position of the aircraft;   a plot TL representing the lateral flight path, that is, the flight path T 0  of the aircraft in the horizontal plane. The corresponding vertical path TV is displayed in the window  3 ;   an angular separation graduation E 1 ;   a distance graduation E 2 ; and   auxiliary characteristic symbols  25 D,  25 E and  25 F located in the horizontal positions of aircraft in the vicinity that are shown, in the set of information  5  relative to the vertical plane, respectively by the symbols  18 D,  18 E and  18 F.       

     In the horizontal plane, the flight path TL comprises a plurality of straight-line segments S 1 , S 2 , S 3  that are joined at way points P 1 , P 2 . In the example of  FIG. 3 , the positions of the aircraft in the vicinity are orthogonally projected on the segment S 1 , S 2 , S 3  of the flight path T 0  which is closest to that actual position. Thus:
         the aircraft in the vicinity illustrated by the symbols  18 D and  25 D is projected onto the segment S 2 ;   the aircraft illustrated by the symbols  18 E and  25 E is projected onto the segment S 2 ; and   the aircraft illustrated by the symbols  18 F and  25 F is projected onto the segment S 3 .       

     Thus, by associating with the graphical representation in the vertical plane (set of information  5 ) according to the invention, a graphical representation in the horizontal plane (set of information  23 ) of the normal type, the device  1  makes it possible for the pilot to improve the perception of the actual situation of his surroundings, since the representation in the horizontal plane provides additional information, such as the bearings of the aircraft in the vicinity for example.