• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a method and a device for avoiding an object by detecting its approach to an aircraft (20). After detecting an object in the environment of an aircraft (20) and its approach, a first trajectory of said object and a second trajectory of said aircraft (20) are estimated from first successive states of said object and second states. successive aircraft (20). Then, a minimum distance (dm) between said first trajectory and said second trajectory is estimated and an alarm is triggered as soon as said minimum distance is lower than a first threshold in order to alert a crew of said aircraft (20) of a risk of collision. Finally, if the minimum distance is less than a second threshold, an avoidance maneuver is automatically performed by said aircraft (20) in order to deviate from said first trajectory and, consequently, to eliminate any risk of collision with said object .
    公开号:FR3070527A1
    申请号:FR1770907
    申请日:2017-08-31
    公开日:2019-03-01
    发明作者:Marc Salesse La Vergne
    申请人:Airbus Helicopters SAS；
    IPC主号:
    专利说明:

    Method and device for avoiding an object by detecting its approach to an aircraft
    The present invention relates to the general technical field of aids for piloting aircraft and in particular to the fields of detection and avoidance of fixed or mobile objects.
    The present invention relates more particularly to a method of avoiding an object by detection of its approach by an aircraft as well as a device implementing this method and that an aircraft having such a device.
    A fixed object is formed, for example, by the terrain surrounding the aircraft, a building, a pylon or even a cable. A mobile object is in turn formed for example by another aircraft, a drone or else a bird. A fixed object is subsequently designated by the term "obstacle" and a mobile object by the term "intruder".
    Today, there are aircraft terrain avoidance alert assistance systems known under the acronym "TAWS" for "Terrain Avoidance Warning System".
    These TAWS systems make it possible to indicate, as they approach, dangerous obstacles and terrain located in front of the aircraft's trajectory. These TAWS systems notably include a function for avoiding overflown relief designated by the acronym in English "FLTA" for "Forward-Looking Terrain Avoidance". Such a system thus makes it possible to automatically produce alerts based on terrain databases and possible obstacles overflown as well as possibly an avoidance trajectory when the trajectory of the aircraft interferes with the terrain or else an obstacle.
    Another system, designated by the acronym "GPWS" in English for "Ground Proximity Warning Systems", makes it possible to alert the pilot of the aircraft of proximity to the ground.
    Active research aims to improve their efficiency by using new sensors such as laser scanning systems for example. Although effective, these systems remain expensive to this day. In this context, imaging systems can be an alternative and help to facilitate the recognition of obstacles, or even be integrated into a set of sensors based on different technologies.
    In addition, rotorcraft, also known as “rotary wing aircraft”, very often operate at very low altitude. The risk of theft in the vicinity of obstacles, and in particular of cables whose visual detection is difficult, is greater and their detection constitutes a major issue for flight safety. Warning systems for the avoidance of specific terrain and suitable for rotorcraft were then developed and are known by the acronym in English "HTAWS" for "Helicopter Terrain Avoidance Warning System".
    In addition, rotorcraft often operating in uncontrolled flight zones, the risk of collision with other aircraft is also significant. Surveillance and avoidance systems designated under the acronym "TCAS" in English for "Traffic and Collision Avoidance System" as well as data exchange systems between aircraft designated under the acronym "ADSB-ln" have been developed or under study. The TCAS standard II system notably uses an avoidance function in cooperative mode between aircraft. However, these systems are expensive and complex to install on rotorcraft due to the large areas required for their antennas.
    In addition, the use of drones of different sizes is democratizing and increasing rapidly. As a result, the risk of an aircraft colliding with a drone also increases. However, due to its small size, the detection and identification of a drone is, like the detection and identification of a bird, difficult and requires sustained attention from the crew of the aircraft. In all cases, this detection and identification may occur late and therefore requires an avoidance maneuver which must often be vigorous.
    As a result, the automation of such an avoidance maneuver proving to be necessary, automatic detection and avoidance systems have been developed and are known under the English designation "Sense and Avoid Systems".
    For example, WO 2016/189112 describes a collision avoidance method for rolling vehicles. An estimate of the trajectory of an object is made following successive detections of several positions of the object. After predicting a future trajectory of the object, a probability of collision is estimated and an alarm is triggered if this probability is greater than a predetermined threshold. An automatic avoidance maneuver can also be performed, such as braking or a change of trajectory.
    Document EP 2200006 is also known, which describes a method for estimating the state of an object and transmitting this state to a collision detection and avoidance system. This method is intended for an aircraft and uses successive images of an object to estimate the state of the object, such as its speed and its position, in supposed cases of minimum and maximum distances between the aircraft and the object.
    In addition, document US 8965679 describes a device and a method making it possible to maintain a safety distance between an unmanned aircraft and an intruder. Indeed, in the event of detection of a distance between the trajectories of an intruder and of the aircraft less than a predetermined threshold, an avoidance solution is developed as a function of the trajectory of the intruder, the aircraft realizing for example, a maneuver to the left if the intruder is heading to the right of the aircraft, also taking into account the constraints linked to the surrounding terrain.
    In addition, the detection of obstacles and their automatic avoidance are the subject of numerous studies, particularly in the field of robotics. Avoidance paths are mainly developed in two dimensions, while avoidance paths performed by an aircraft are more effective if they are performed in three dimensions. However, the search for avoidance paths in three dimensions leads to a significantly higher complexity than in two dimensions.
    The effectiveness of the avoidance path depends first of all on minimizing the uncertainty of the state of an object approaching the aircraft, typically its position, speed and / or acceleration. This effectiveness also depends on adaptation decisions based on the uncertainty of this state, in particular to anticipate future movements of the object when it is a moving object, namely an intruder. Finally, this efficiency depends on the actual avoidance trajectory, which must be established in a realistic, optimal way, adapted to the aircraft as well as to the object in order to ensure the reliability and success of the avoidance.
    A detection and avoidance process must therefore generate an alert and / or automatically perform an avoidance maneuver at the right time, while remaining reliable and safe in terms of object avoidance possibilities. detected.
    Consequently, the subject of the present invention is a method of avoiding an object by detecting its approach by an aircraft making it possible to overcome the limitations mentioned above, in particular by exploiting the distance between the estimated trajectory of the object, when it is mobile, and the estimated trajectory of the aircraft in order to assess the risk of collision and to anticipate it, if this margin becomes too low, by alerting the crew of the aircraft or by performing a maneuver avoidance.
    In this context, the present invention provides a method of avoiding an object by detecting its approach to an aircraft comprising the following steps:
    - detection of an object approaching the aircraft,
    - a first estimate of first states successive of the object,- a second estimate of second states successive of the aircraft,- a first characterization of a first path of the object,- a second characterization of a second path of
    the aircraft,
    - a third estimate of a distance between the first trajectory of the object and the second trajectory of the aircraft,
    a fourth estimate of a minimum distance between the first trajectory of the object and the second trajectory of the aircraft, and
    - an alarm when this minimum distance is less than a first threshold.
    This method is suitable for the detection of fixed objects, namely the terrain surrounding the aircraft as well as any obstacle such as a building, a pylon or else a cable for example, as well as mobile objects, namely intruders moving in the environment of the aircraft, such as another aircraft, a drone, or even a bird for example.
    The object is detected by a detection device on the aircraft. This detection device also makes it possible to estimate the first successive states of the object. These first states are made up of the position, speed and acceleration of the object. This position, this speed and this acceleration are defined relative to the aircraft by the detection device, namely in a local coordinate system of the aircraft.
    It is possible that the acceleration of the object cannot be estimated by the detection device. In this case, this acceleration can be considered constant and estimated from the speeds of the object, or even considered to be zero, the speed of the object then being substantially constant.
    The object detection device is for example formed by an electromagnetic wave detection system, for example a RADAR system according to the expression in English "RAdio Detection And Ranging". The electromagnetic wave detection system includes a generator and a receiver of electromagnetic waves. This detection system uses these electromagnetic waves to detect the presence of an object in the environment of the aircraft, typically by the issuance of "radar plots", and can also estimate the first successive states of the object.
    The object detection device can also be an optical detection system, for example by optical telemetry. This optical detection system typically makes it possible to scan the environment of the aircraft by sequential emission / reception of a light beam, for example a LASER beam. In this way, an optical detection system makes it possible to detect the presence of an object in the environment of the aircraft and to estimate the first successive states of the object. An optical detection system is for example of the LIDAR type according to the expression in English "Llght Detection and Ranging".
    The object detection device can also be an imaging system composed of at least one camera enabling the delivery of a succession of images of the environment of the aircraft. Then, processing of these successive images of the environment of the aircraft, according to one of the existing and known techniques, makes it possible to detect the presence of an object in the environment of the aircraft and to estimate the relative position and the relative speed of this object as well as its acceleration, and therefore the first successive states of the object.
    The processing of the images and the first estimation of the first successive states of the object are carried out by at least one computer present in the aircraft. This calculator can be dedicated to these tasks only, dedicated to the complete implementation of the method according to the invention or else shared with one or more other functions of the aircraft. For example, this calculator is the flight calculator of the aircraft.
    In addition, the imaging system may include at least two cameras with different focal distances, in particular for better scanning of the environment of the aircraft. In fact, the use of two cameras with different focal distances advantageously makes it possible on the one hand to have a wide field of vision with the camera of short focal distance, and on the other hand to "zoom" with the camera provided with the longer focal length in order to have a restricted field of vision, but with better precision, over a particular area of the environment of the aircraft, in particular where an intruder has been detected.
    However, an imaging system may encounter observability problems with the object, for example depending on the size of the object, its shape and / or its distance from the aircraft. In this case, assumptions can be made about the size of the object and its speed range. Different object classes can thus be defined according to the sizes and the associated speed domain.
    Several hypotheses can be taken into account simultaneously, the size of the object in the image then making it possible to estimate a distance between the object and the aircraft according to each class chosen. The consistency of each class with respect to the speed domain is then checked. For each of the coherent classes, a minimum distance between the first trajectory of the object and the second trajectory of the aircraft is then estimated and the minimum value of the minimum distances associated with each class is for example used by the method according to the invention .
    The detection device can also combine on the one hand an imaging system and on the other hand an electromagnetic wave detection system or else an optical telemetry system. In this way, the imaging system makes it possible to estimate in particular the angles between the object and the aircraft while the electromagnetic wave detection system or else the optical telemetry system advantageously makes it possible to estimate the current distance between the object and aircraft. As a result, the object detection device limits or even eliminates these object observability problems. The detection of the object is then more precise and faster, thereby improving the first estimate of the first states of the object.
    In addition, the combination of several detection devices makes it possible to create an asymmetry of means favorable to the safety of the avoidance device according to the invention. For example, an optical telemetry system will be able to detect an object in the shadows, which is therefore barely visible and possibly not detected by the imaging system.
    The object detection device can also be an ADSB-ln system for exchanging data between aircraft, also making it possible to provide the first successive states of an object, when this object is another aircraft also equipped with an ADSB system. -ln data exchange.
    An analysis of the first states of the detected object makes it possible to define if this object approaches the aircraft, then triggering the following steps of the method according to the invention, or else if it is fixed with respect to the aircraft or moving away from it, the application of this method then being limited to the step of detecting an object approaching the aircraft.
    The second successive states of the aircraft are estimated by an aircraft location device. These second states are made up of the position, speed and acceleration of the aircraft. This position, this speed and this acceleration of the aircraft are generally estimated absolutely in a terrestrial frame by the location device.
    The location device is for example formed by a GA / SS type satellite receiver for the designation in English “Global Navigation Satellite System”. The location device can also be formed by an inertial unit. An inertial unit is an instrument capable of integrating the movements it undergoes, in particular accelerations and angular speeds, to provide estimates of its orientation, its linear speed as well as its position.
    Once the first successive states of the object and the second successive states of the aircraft are known, a first trajectory of the object and a second trajectory of the aircraft are defined respectively from these first successive states of the object and of these second successive states of the aircraft.
    The first trajectory thus establishes the past path followed by the object and makes it possible to predict the future path of the object. The second trajectory does the same for the aircraft. In the particular case where the object is fixed, the first trajectory is limited to a point in the terrestrial frame.
    To be compared, the first trajectory of the object and the second trajectory of the aircraft must be established in a common coordinate system. Preferably, this common coordinate system is the terrestrial coordinate system in which the second states of the aircraft are estimated. To establish the first trajectory of the object in this terrestrial coordinate system, it is typically possible to transfer the first states of the object in this terrestrial coordinate system and then to establish the first trajectory in this terrestrial coordinate system or else to establish the first trajectory in the local coordinate system of the aircraft then to transfer it to this terrestrial coordinate system.
    The first trajectory and the second trajectory are characterized respectively by a set of equations as a function of time, thus defining the respective positions of the object and of the aircraft in the terrestrial frame of reference. The set of equations characterizing the first trajectory of the object in the terrestrial frame is determined from the first successive states of the object and the second successive states of the aircraft, the first successive states characterizing the object relative to the aircraft and the second successive states characterizing the aircraft absolutely. The set of equations characterizing the second trajectory of the aircraft in the terrestrial reference frame is determined only from the second successive states characterizing the aircraft in an absolute manner.
    Each set of equations has three equations to define the three coordinates of the object and those of the aircraft in the Earth coordinate system.
    The past and future evolutions of the object and the aircraft having been estimated, it is then possible to characterize the distance separating the first trajectory of the object and the second trajectory of the aircraft as a function of time. This distance between the first trajectory and the second trajectory can be estimated by a polynomial function defined from these two sets of equations.
    The sets of equations characterizing the first and second trajectories as well as the polynomial function characterizing the distance separating these first and second trajectories are defined by at least one computer. This calculator can be dedicated to the establishment of these sets of equations, shared in particular for the estimates of the states of the object and of the aircraft or else already present in the aircraft and shared with one or more other functions of the 'aircraft. The sets of equations and the polynomial function are thus defined from the first states of the object, namely its position, its speed and its acceleration, and from the second states of the aircraft, namely its position, its speed and its acceleration.
    In addition, in order to simplify the sets of equations as well as the polynomial function and, in fact, to limit their complexities and to facilitate their resolution, hypotheses can be taken in particular on the evolution of the object and / or that of the aircraft. For example, considering that the object and the aircraft evolve with constant acceleration, the first trajectory and the second trajectory can be characterized respectively by a set of three second order equations. Consequently, the distance between the first trajectory of the object and the second trajectory of the aircraft can be characterized by a polynomial function of degree four at most defined from the two sets of three second order equations.
    Then, the risk of collision between the object and the aircraft is determined from the fourth estimate of a minimum distance between the first trajectory of the object and the second trajectory of the aircraft, and in particular between the paths object and aircraft.
    The fourth estimate of this minimum distance is the minimum value of the polynomial function. The fourth estimate of the minimum distance is made only between the future paths of the object and those of the aircraft.
    The fourth estimate of the minimum distance between the first trajectory and the second trajectory can be carried out by an estimator calculating the minimum distance by derivation with respect to time of the polynomial function characterizing the distance between the first trajectory and the second trajectory and looking for the value time that minimizes this distance. This estimator is preferably integrated into the previously mentioned calculator and carrying out, inter alia, the estimates of the states and trajectories of the object and those of the aircraft.
    On the assumption of a constant acceleration of the object and the aircraft, the polynomial function of time characterizing the distance between the first and second trajectories is a polynomial function of degree four. Its derivative with respect to time is therefore a polynomial function of degree three. The minimum distance is obtained for a particular time value canceling this derivative. One or three particular time values cancel this derivative formed by the polynomial function of degree three.
    When a single particular time value cancels this derivative, the minimum distance is therefore defined for this particular time value applied to the polynomial function characterizing the distance between the first and second trajectories.
    When three particular time values cancel this derivative, to each particular time value corresponds a local extremum of the polynomial time function. Among these local extrema, a single local extremum constitutes the minimum distance between the first and second trajectories.
    The method according to the invention makes it possible to identify a first level of risk of collision between the object and the aircraft.
    When the minimum distance associated with the particular time value determined is less than a first threshold, an alarm is triggered. In this way, the pilot of the aircraft is alerted that an object is approaching the aircraft and that it would be prudent for an avoidance maneuver to be carried out quickly so that the aircraft moves away from this object, thus eliminating the risk of collision. The pilot can be located in the aircraft or deported in the case of an unmanned aircraft.
    This alarm is issued by an alert device. This alarm can be visual, displaying for example a specific message or symbol on a screen, and / or audible, for example emitting one or more sounds or a voice announcement audible by the pilot. In all cases, this alarm must be sufficiently explicit to allow the pilot to identify the situation and perform the appropriate maneuver.
    According to a particular embodiment of the invention, the method of avoiding an object by detecting its approximation according to the invention comprises an additional step of automatic realization of an object avoidance maneuver by the aircraft as soon as the minimum distance is less than a second threshold, the second threshold being less than the first threshold.
    In fact, as soon as the minimum distance associated with the particular time value determined is less than the second threshold, a second level of risk of collision between the object and the aircraft is reached and an object avoidance maneuver by the aircraft is carried out automatically. In this case, the first trajectory of the object tends to come dangerously close to the second trajectory of the aircraft and it is necessary to initiate an avoidance maneuver as quickly as possible. Consequently, in order to avoid any risk of collision, the aircraft automatically performs the avoidance maneuver in order to move away from the object detected.
    In an exemplary embodiment adapted to a rotary wing aircraft, the first threshold is equal to 1 nautical mile (1 Nm), which is equal to 1852 meters (1852 m) and the second threshold is equal to 0.5 Nm.
    However, since the detected object can be distant from the aircraft, it is not necessary to trigger an alarm or to initiate an avoidance maneuver immediately, even if the first trajectory of the object and the second trajectory of the aircraft tend to approach. Indeed, on the one hand the errors of estimation of the first states of a distant object are likely to be significant and on the other hand the necessities of air traffic impose crossing points common to all aircraft. The risk of collision between the object and the aircraft is therefore not proven, it is then preferable to wait until the object approaches the aircraft in order to confirm whether the first trajectory of the object approaches well. of the second trajectory of the aircraft or if these two trajectories move away from one another.
    In fact, the method according to the invention may include a step of inhibiting the triggering of the alarm or else the automatic carrying out of an avoidance maneuver, as long as a current distance between the object and the aircraft is greater than a distance threshold, this current distance between the object and the aircraft being estimated by the detection device of the aircraft. The distance threshold is for example equal to 2 Nm.
    To perform this avoidance maneuver, the method according to the invention communicates with an automatic pilot that the aircraft comprises and provides it, for example, with avoidance orders corresponding to this avoidance maneuver.
    In addition, according to this particular embodiment of the invention, the method according to the invention can define an avoidance maneuver so that the aircraft quickly moves away from the object by maximizing the distance between the first trajectory of the object and the second trajectory of the aircraft associated with the particular time value previously determined. Preferably, this avoidance maneuver is performed with a particular acceleration of the aircraft making it possible to maximize this distance between the first trajectory and the second trajectory associated with the particular time value previously determined.
    This particular acceleration is estimated by the application for example of a set of equations determining this distance between the first trajectory of the detected object and the second trajectory of the aircraft making it possible to determine the instant when this distance is minimum, namely the particular time value associated with this minimum distance, then by calculating an acceleration vector of the aircraft maximizing this minimum distance.
    Then, it is necessary to use this acceleration vector to predict a new second trajectory of the aircraft and to verify the minimum distance between the first trajectory of the detected object and this new second trajectory of the aircraft is greater than the first threshold to ensure that any risk of collision is eliminated during the entire avoidance maneuver.
    In the majority of cases, this calculation is sufficient to obtain a new second trajectory of the aircraft with a minimum distance from the first trajectory of the detected object greater than the first threshold.
    However, it is possible in special cases, particularly near reliefs or when several intruders are detected simultaneously such as birds in a group, that this new second trajectory of the aircraft does not make it possible to obtain a minimum distance with the first trajectory of a detected intruder greater than the first threshold.
    Consequently, if a risk of collision still exists, the minimum distance between the first trajectory and the new second trajectory being less than the first threshold, at least one iteration of this calculation of the acceleration vector is necessary in order to obtain a minimum distance between the first trajectory of a detected object and a new second trajectory of the aircraft sufficient, namely greater than the first threshold. It is therefore appropriate, the aircraft and each intruder having continued their progressions on their respective trajectories during this first calculation, to determine a new minimum distance between these trajectories, to calculate a new acceleration vector which maximizes it and to determine a new second trajectory of the aircraft using this new acceleration vector. Then, after checking that this new second trajectory of the aircraft makes it possible to obtain a minimum distance with the first trajectory of the detected object greater than the first threshold, this new second trajectory is used by the aircraft or else a new iteration of this calculation is carried out again if necessary.
    In particular, the particular acceleration maximizing the distance between the first trajectory of the object and the second trajectory of the aircraft can be estimated by deriving the minimum distance (dm) from each of the components of the acceleration vector of the aircraft to determine the particular acceleration of the aircraft that maximizes this minimum distance (dm).
    However, the avoidance maneuver is preferably carried out with priority given to the comfort of the crew and that of the passengers, as well as to the operational aspects of the aircraft. For example, "operational aspects" means uncertainty about the position of the aircraft and the position of the surrounding reliefs. For this purpose, a limit acceleration is defined. Therefore, if the particular acceleration previously defined is greater than this limit acceleration, the avoidance maneuver is performed with the limit acceleration. This limiting acceleration is for example equal to a quarter of the acceleration of terrestrial gravity.
    In addition, this avoidance maneuver may include a change of course allowing a coordinated turn to be made.
    In this way, the method according to the invention makes it possible to anticipate the risk of a collision between the aircraft and the object and guarantees the automatic implementation of an avoidance maneuver maximizing the minimum passage distance between the aircraft and the object detected at the cost of a simple implementation and therefore easily achievable in a flight computer of an aircraft.
    In addition, the method according to the invention may include an additional step of displaying the object on a display device. In this way, the pilot of the aircraft can visualize the position of the object with respect to the aircraft and its progress on the display device, thus facilitating its direct location by the crew of the aircraft. outside the aircraft. The display device can be a screen present in the aircraft, a Human Machine Interface device called HMI, a head-up vision device or a visualization system integrated into a helmet of the pilot of the aircraft.
    The subject of the invention is also a device for avoiding an object by detecting its approaching intended to equip an aircraft, the device comprising:
    - an object detection device providing a first state of the object,
    - an aircraft location device providing a second state of the aircraft,
    - at least one memory storing in particular calculation instructions, first successive states of the object and second successive states of the aircraft,
    at least one computer capable of executing the calculation instructions and implementing the method described above,
    - at least one alert device connected to the computer.
    This device for avoiding an object by detecting its approach then allows the implementation of the method described above.
    This avoidance device is also connected to the automatic pilot of the aircraft in order to control the carrying out of the avoidance maneuver when the conditions require it.
    Another object of the invention is an aircraft comprising in particular an automatic pilot and an object avoidance device by detecting its approach previously described.
    The invention and its advantages will appear in more detail in the context of the description which follows with examples of embodiment given by way of illustration with reference to the appended figures which represent:
    FIG. 1, a rotary wing aircraft fitted with an object avoidance device by detecting its approach,
    FIG. 2, a block diagram of a method for avoiding an object by detecting its approach,
    - Figure 3 a view of an aircraft, objects in its environment and their trajectories.
    The elements present in several separate figures are assigned a single reference.
    FIG. 1 represents an aircraft 20 with rotary wing comprising in particular a fuselage 21, a main rotor 22 ensuring its lift, or even its propulsion, and a rear rotor 23. This aircraft 20 also comprises an automatic pilot 24, a device 50 for avoiding an object 10 by detection of its approximation and a dashboard 25 provided with a screen 56.
    The device 50 comprises a device 51 for detecting an object 10 located in the environment of the aircraft 20 and providing a first state of this object 10, a device 52 for locating the aircraft 20 providing a second state of the aircraft 20, at least one memory 53 storing calculation instructions, first successive states of the object 10 and second successive states of the aircraft 20, at least one computer 54 capable of executing these calculation instructions and at least an alert system.
    Indeed, aircraft, and in particular rotary-wing aircraft, can operate in uncontrolled flight zones in which the risk of collision with a flying object in these zones is significant. Such a mobile object 10 can for example be another aircraft, a drone, or even a bird, considered as an intruder in the environment of the aircraft 20.
    The risk of collision with a fixed object 10, formed by the terrain surrounding the aircraft 20 or else an obstacle on this terrain, also exists when the aircraft 20 flies at very low altitude.
    This device 50 aims to limit, or even eliminate, this risk of collision by implementing a method for avoiding an object 10 by detecting its approach, a block diagram with its different stages is shown in FIG. 2 .
    FIG. 3 represents the aircraft 20 and its environment in which two objects 10, 10 ′ operate. Two marks are also shown in FIG. 3. A local mark (Xl, Yl, Zl), attached to the aircraft 20 is formed by three directions X | _, Yl and Z L orthogonal to each other and fixed screws with respect to the aircraft 20. A terrestrial coordinate system (Χγ, Υτ, Ζγ) is itself formed for example by the direction of North, the direction of East and a vertical direction oriented downwards and corresponding to the direction of Earth's gravity.
    The method of avoiding an object 10 by detecting its approach to an aircraft 20 firstly comprises a detection 101 of an object 10 approaching the aircraft 20. This detection of an object 10 approaching of the aircraft 20 is performed by a detection device 51. This detection device 51 is for example formed by an electromagnetic wave detection system, an optical detection system or else an imaging system composed of at least one camera. This detection device 51 is capable of detecting a fixed or mobile object 10,10 ′ located in the environment of the aircraft 20 and also of estimating first successive states of the object 10,10 ′, namely its position, speed and acceleration.
    Therefore, this detection device 51 can thus estimate whether the object 10.10 ’, thanks to its first successive states, approaches the aircraft 20 or on the contrary moves away from it.
    In the case shown in FIG. 3, it can be seen that a first object 10 has a first trajectory 16 approaching the aircraft 20 and the second trajectory 26 of the aircraft 20 while a second object 10 'has a first trajectory 16 ′ moving away from the aircraft 20 and from its second trajectory 26. Consequently, the avoidance method will ignore in the following steps this second object 10 ′ which presents no risk of collision with the aircraft 20 and focus the first object 10 which may present a risk of collision with the aircraft 20.
    Then, a first estimate 102 of the first successive states of the object 10 is carried out by means of the detection device 51. The position, the speed and the acceleration of the object 10 forming these first states are defined in the reference frame local (Xl, Yl, Z | _) of the aircraft 20, namely relative to the aircraft 20. These first successive states of the object 10 can be temporarily stored in the memory 53.
    Then, a second estimate 103 of second successive states of the aircraft 20 is carried out by means of a location device 52. As for object 10, the second states of the aircraft 20 are formed by the position, the speed and acceleration of the aircraft 20. The position, the speed and the acceleration of the aircraft 20 are estimated in the terrestrial frame of reference (X t , Yt, Z t ). These second successive states of the aircraft 20 can be temporarily stored in the memory 53. The location device 52 is for example formed by at least one GNSS receiver, at least one inertial unit, or even a combination of several of these pieces of equipment in order to '' improve accuracy and reliability.
    Following these estimates 102, 103 of the first and second successive states, a first characterization 104 of a first trajectory 16 of the object 10 is carried out. This first trajectory 16 of the object 10 is established in the terrestrial frame of reference (X t , Yt, Z t ) by the computer 54 from the first successive states of the object 10 and the second successive states of the aircraft 20 stored in memory 53.
    In parallel, a second characterization 105 of a second trajectory 26 of the aircraft 20 is carried out. This second trajectory 26 of the aircraft 20 is also established in the terrestrial coordinate system (X t , Yt, Z t ) by the computer 54 from the second successive states of the aircraft 20 stored in the memory 53. This second characterization 105 a second trajectory 26 of the aircraft 20 can also be carried out sequentially, after the first characterization 104 of a first trajectory 16 of the object 10.
    The first trajectory 16 of the object 10 and the second trajectory 26 of the aircraft 20 are characterized respectively by a set of three equations as a function of time respectively giving the position of the object 10 and that of the aircraft 20 in the terrestrial reference (Χγ, Υτ, Ζγ).
    These equations can be simplified by taking for example the hypothesis that the object 10 and the aircraft 20 have a constant acceleration. These equations are then second order. We thus obtain for the first trajectory 16 of object 10:
    Y) = Xoi + VxOi t + “ G xOi t 2 '
    Y 0 = Ÿoi + VyOi t + “^ y oi t2,
    Zo = Zoi + V Z 0i t + “ G zOi with
    - Xo, Yo, Zo, the coordinates of the object 10 in the terrestrial frame (Χτ, Υτ, Ζτ), the coefficients of these equations being determined from the estimates of the first successive states of the object 10 and the second states successive aircraft 20,
    Xoii Yoii Z oi corresponding to the initial coordinates of the object 10 in the terrestrial frame of reference (Χτ, Υτ, Ζτ),
    - Υχοίι Vyoii Vzoîi corresponding to the initial velocities of the object 10 according to the directions of the terrestrial frame of reference (Χτ, Υτ, Ζτ), and
    - G xOi , G yOi , G zOi , being the accelerations of the object 10 according to the directions of the terrestrial frame of reference (Χτ, Υτ, Ζτ).
    Similarly, we obtain for the second trajectory 26 of the aircraft 20:
    Xh = Xhî + V xHi t + 2 G xHi t 2 '
    Yh = Yhî + VyHi f + 2 G yHi
    ZH = Zhî + VzHi f + 2 G zHi t 2 , with
    - Xh, Yh, Zh, the coordinates of the aircraft 20 in the terrestrial frame of reference (Χτ, Υτ, Ζτ), the coefficients of these equations being determined from the estimates of the second successive states of the aircraft 20,
    - Xhî, Yhî, Zhî corresponding to the initial coordinates of the aircraft 20 in the terrestrial frame of reference (X t , Yt, Z t ),
    - Vxhî, VyHi, V Z Hi, corresponding to the initial speeds of the aircraft according to the directions of the terrestrial frame of reference (X t , Yt, Z t ), and
    - Gxhî, GyHi, G Z Hi, being the accelerations of the aircraft 20 according to the directions of the terrestrial frame of reference (Χγ, Υτ, Ζγ).
    A third estimate 106 of a distance between the first trajectory 16 of the object 10 and the second trajectory 26 of the aircraft 20 is then carried out. This distance between the first trajectory 16 and the second trajectory 26 is defined from the two sets of three equations characterizing the first and second trajectories 16,26 by a polynomial function of time such that: d 2 = (x 0 + x H y + (y 0 + Y H y + (z 0 + z H y.
    Considering the assumption of a constant acceleration of the object 10 and that of the aircraft 20, this polynomial function of time is of degree four such that:
    D 2 = (Xo + XH) 2 + (y0 + Y H ) 2 + (Z o + Z H ) 2 = / (t 4 , t 3 , t 2 , t).
    These sets of equations as well as the polynomial function of time can be temporarily stored in memory 53
    A fourth estimate 107 of a minimum distance d m between the first trajectory 16 of the object 10 and the second trajectory 26 of the aircraft 20 is then carried out in order to identify a possible risk of collision between the object 10 and the aircraft 20. This minimum distance d m corresponds to a particular time value canceling the derivative with respect to time of the polynomial time function defining the distance between the first trajectory 16 and the second trajectory 26.
    According to the assumption of constant acceleration of the object 10 and of the aircraft 20, this derivative with respect to time is a polynomial function of degree three. Consequently, there can exist one or three particular time values canceling out this derivative formed by the polynomial function of degree three according to the characteristics of this derivative. However, a single particular time value generally corresponds to a minimum distance d m between the first and second trajectories 16,26. This minimum distance d m is visible in Figure 3.
    Finally, as a function of this minimum distance d m , an alarm 108 may be triggered to alert the crew of the aircraft 20 of a risk of collision between the object 10 and the aircraft 20. The trigger 108 an alarm is then produced when the minimum distance d m is less than a first threshold corresponding to a first level of risk of collision between the object 10 and the aircraft 20.
    This alarm is for example audible and emitted by the alert device 55, emitting sounds or even a voice announcement. This alarm can also be visual, displaying a specific message or symbol on the screen 56 of the aircraft 20.
    The crew of aircraft 20, and the pilot in particular, are thus informed of the situation of aircraft 20, namely the first level of risk of collision and that a suitable avoidance maneuver must be carried out.
    In addition, this avoidance process can include one, two or three optional steps.
    For example, this avoidance method may include an additional step 109 of an avoidance maneuver by the aircraft 20 of the object 10 as soon as the minimum distance d m is less than a second threshold. The second threshold is lower than the first threshold and corresponds to a second level of risk of collision between the object 10 and the aircraft 20. In fact, the minimum distance d m is smaller than previously and the risk of collision between the object 10 and aircraft 20 is higher.
    The avoidance maneuver is preferably carried out with a particular acceleration of the aircraft 20 making it possible to maximize the distance between the first trajectory 16 and the second trajectory 26 corresponding to the particular time value associated with the minimum distance d m . However, when this particular acceleration is greater than a limit acceleration, the avoidance maneuver is performed with this limit acceleration in order to preserve the comfort of the crew and that of the passengers of the aircraft 20.
    The execution 109 of the object avoidance maneuver 10 by the aircraft 20 is carried out automatically, generally by the automatic pilot 24 of the aircraft 20, avoidance orders being supplied by the computer 54 to the pilot automatic 24. The carrying out 109 of this avoidance maneuver is carried out in parallel with the triggering 108 of an alarm.
    This avoidance method can also include a step of inhibiting 110 the triggering 108 of an alarm and the carrying out 109 of an avoidance maneuver. This inhibition step 110 avoids the triggering 108 of an alarm and the carrying out 109 of an avoidance maneuver when the detected object 10 is distant from the aircraft 20. In fact, a detected object 10 can have initially a first trajectory approaching the second trajectory of the aircraft 20, characterizing a risk of collision. Then the first trajectory of the object 10 can evolve to deviate from the second trajectory of the aircraft 20, the risk of collision previously determined no longer having to be.
    The inhibition step 110 is for example activated when the current distance between the object 10 and the aircraft 20 is greater than a distance threshold.
    This avoidance process can also include a complementary step 5 of displaying 111 of the object 10 on the screen 56, which can be carried out in parallel with the other steps of this process. In this way, the pilot of the aircraft 20 can follow the evolution of the object 10 with respect to the aircraft 20 and its approach with respect to the aircraft 20. This display can also represent the first 10 trajectory 16 of the object 10 and the second trajectory 26 of the aircraft 20 as shown for example in FIG. 3.
    Naturally, the present invention is subject to numerous variations as to its implementation. Although several embodiments have been described, it will be understood that it is not conceivable to identify exhaustively all the possible modes. It is of course conceivable to replace a means described by an equivalent means without departing from the scope of the present invention.
    权利要求:
    Claims (14)
    [1" id="c-fr-0001]
    1- A method of avoiding an object (10) by detecting its approach to an aircraft (20), said aircraft (20) comprising a detection device (51) and a location device (52), characterized in that said method comprises the following steps:
    a detection (101) of an object (10) approaching said aircraft (20), said object (10) being detected by said detection device (51),
    a first estimate (102) of first successive states of said object (10), said first successive states of said object (10) being estimated by said detection device (51),
    - a second estimate (103) of second successive states of said aircraft (20), said second successive states of said aircraft (20) being estimated by said location device (52)
    - a first characterization (104) of a first trajectory (16) of said object (10),
    - a second characterization (105) of a second trajectory (26) of said aircraft (20),
    a third estimate (106) of a distance between said first trajectory (16) of said object (10) and said second trajectory (26) of said aircraft (20),
    a fourth estimate (107) of a minimum distance (d m ) between said first trajectory (16) of said object (10) and said second trajectory (26) of said aircraft (20), and
    - triggering (108) of an alarm when said minimum distance (d m ) is less than a first threshold.
    [2" id="c-fr-0002]
    2- A method according to claim 1 characterized in that said first trajectory (16) of said object (10) and said second trajectory (26) of said aircraft (20) are defined respectively from said first successive states of said object (10) and said second successive states of said aircraft (20) and characterized respectively by a set of three equations as a function of time, and said distance between said first trajectory (16) of said object (10) and said second trajectory (26) of said aircraft (20) is characterized by a polynomial function of time defined from said two sets of three equations.
    [3" id="c-fr-0003]
    3- Method according to claim 2, characterized in that, said object (10) and said aircraft (20) being considered to have a constant acceleration, said first trajectory (16) of said object (10) and said second trajectory (26) of said aircraft (20) are respectively characterized by a set of three second order equations so that said distance between said first trajectory (16) of said object (10) and said second trajectory (26) of said aircraft (20) is characterized by a function polynomial of degree four.
    [4" id="c-fr-0004]
    4- A method according to any one of claims 1 to 3, characterized in that said detection device (51) is formed by an electromagnetic wave detection system, an optical detection system, an imaging system composed of at least one camera or else an imaging system composed of at least one camera combined with an electromagnetic wave detection system or else an optical detection system.
    [5" id="c-fr-0005]
    5- Method according to any one of claims 4 to 4, characterized in that said location device (52) is formed by at least one GNSS receiver and / or at least one inertial unit.
    [6" id="c-fr-0006]
    6- A method according to any one of claims 1 to 5, characterized in that said fourth estimate (107) of said minimum distance (d m ) between said first trajectory (16) of said object (10) and said second trajectory (26 ) of said aircraft (20) is produced by derivation with respect to time of the distance between said first trajectory (16) and said second trajectory (26) and by searching for the value of time which minimizes said distance.
    [7" id="c-fr-0007]
    7- Method according to any one of claims 1 to 6, characterized in that said method comprises a complementary display step (111) of said object (10) on a display device (56).
    [8" id="c-fr-0008]
    8- Method according to any one of claims 1 to 7, characterized in that said method comprises an additional step of performing (109) an avoidance maneuver of said object (10) by said aircraft (20) as soon as said minimum distance (d m ) is less than a second threshold, said second threshold being less than said first threshold.
    [9" id="c-fr-0009]
    9- Method according to claim 8, characterized in that said avoidance maneuver is carried out with a particular acceleration of said aircraft (20) making it possible to maximize said distance between said first trajectory (16) of said object (10) and said second trajectory ( 26) of said aircraft (20) corresponding to a particular time value associated with said minimum distance (d m ).
    [10" id="c-fr-0010]
    10- Method according to claim 9, characterized in that said particular acceleration of said aircraft (20) allowing to maximize said distance between said first trajectory (16) of said object (10) and said second trajectory (26) of said aircraft (20) is estimated by derivation of said minimum distance (dm) from each of the components of the acceleration vector of said aircraft (20).
    [11" id="c-fr-0011]
    11- Method according to any one of claims 9 to 10, characterized in that when said particular acceleration is greater than a limit acceleration, said avoidance maneuver is performed with said limit acceleration.
    [12" id="c-fr-0012]
    12- Method according to any one of claims 8 to 11, characterized in that, said aircraft (20) comprising an automatic pilot (24), said embodiment (109) of said avoidance maneuver of said object (10) by said aircraft (20) is performed by said autopilot (24), avoidance orders being provided to said autopilot (24).
    [13" id="c-fr-0013]
    13- Device (50) for avoiding an object (10) by detection of its approach intended to equip an aircraft (20), said device (50) comprising:
    - a detection device (51) of said object (10) providing a first state of said object (10),
    a location device (52) of said aircraft (20) providing a second state of said aircraft (20),
    at least one memory (53) storing calculation instructions, first successive states of said object (10) and second successive states of said aircraft (20),
    - at least one computer (54) capable of executing said calculation instructions, and
    - at least one alert device (55) connected to said computer (54), characterized in that said device (50) is capable of implementing the method according to one of claims 1 to 12.
    [14" id="c-fr-0014]
    14-aircraft (20) comprising an automatic pilot (24), characterized in that said aircraft (20) comprises a device (50) for avoiding an object (10) by detection of its approach according to claim 13.
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    同族专利:
    公开号 | 公开日
    EP3451314B1|2021-11-10|
    EP3451314A1|2019-03-06|
    FR3070527B1|2020-11-06|
    US10643481B2|2020-05-05|
    US20190088146A1|2019-03-21|
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    法律状态:
    2019-03-01| PLSC| Publication of the preliminary search report|Effective date: 20190301 |
    2019-08-22| PLFP| Fee payment|Year of fee payment: 3 |
    2020-08-21| PLFP| Fee payment|Year of fee payment: 4 |
    2021-08-19| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1770907|2017-08-31|
    FR1770907A|FR3070527B1|2017-08-31|2017-08-31|METHOD AND DEVICE FOR AVOIDING AN OBJECT BY DETECTION OF ITS APPROACH TO AN AIRCRAFT|FR1770907A| FR3070527B1|2017-08-31|2017-08-31|METHOD AND DEVICE FOR AVOIDING AN OBJECT BY DETECTION OF ITS APPROACH TO AN AIRCRAFT|
    EP18190401.2A| EP3451314B1|2017-08-31|2018-08-23|Method and device for avoidance of an object by detection of its proximity to an aircraft|
    US16/117,807| US10643481B2|2017-08-31|2018-08-30|Method and a device for avoiding an object by detecting its approach to an aircraft|
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