Method for avoiding missiles

Abstract

There is provided a method involving an aircraft in an airspace, the method comprising, a) receiving a position of a hostile platform, b) receiving a position of the aircraft, and generating and updating a simulated missile, where the missile is simulated as fired from the hostile platform and being headed towards the aircraft, and c) repeatedly determining an avoiding flight path (4) that makes the aircraft avoid the missile, by generating a plurality of hypothetical flight paths and selecting an avoiding flight path (4) that makes the aircraft avoid the missile.

Description

[0001] Method for avoiding missiles

[0002]

[0003] There have been multiple incidents of civilian aircraft having been shot down by surface-to -air missiles. Surface-to-air missiles, or other types of missiles, fired by terrorists, is an increasing danger to civilian aircraft. There is a need for methods and system that aid pilots in decision-making in order to avoid missiles.

[0004] of invention

[0005] In a first aspect of the invention there is provided method involving an aircraft in an airspace, the method comprising,

[0006] a) receiving a position of a hostile platform,

[0007] b) receiving a position of the aircraft, and generating and updating a simulated missile, where the missile is simulated as fired from the hostile platform and being headed towards the aircraft, and

[0008] c) repeatedly determining an avoiding flight path that makes the aircraft avoid the missile, by generating a plurality of hypothetical flight paths and selecting an avoiding flight path that makes the aircraft avoid the missile.

[0009] This provides an efficient way of determining a safe flight path for the aircraft. The avoiding flight path may be provided to the pilot of the aircraft and thereby assist the pilot in avoiding a true missile that is fired from the hostile platform.

[0010] In various embodiments, the avoiding flight path comprises a first manoeuvre and a predetermined second manoeuvre carried out after the first manoeuvre. In various embodiments, step a) is carried out repeatedly.In various embodiments, step c) is carried out by generating a number of first manoeuvres for the aircraft and time point or position at which the aircraft carries out a predetermined second manoeuvre that makes the aircraft avoid the simulated missile.

[0011] In various embodiments, the predetermined second manoeuvre is defined by at least one predetermined flight dynamic parameter.

[0012] In various embodiments, the predetermined second manoeuvre is a turn in the horizontal plane that subjects the aircraft to a predetermined G-force.

[0013] In various embodiments, the first manoeuvre comprises a turn in the horizontal plane that makes the aircraft assume a straight flight direction, the avoiding flight path being determined by determining, for the flight direction, a time point or position at which the aircraft carries out a predetermined second manoeuvre that makes the aircraft avoid the simulated missile.

[0014] In various embodiments, a plurality of avoiding flight paths is determined.

[0015] In various embodiments, an area in the horizontal plane where the aircraft avoids the missile is determined by determining a plurality of avoiding flight paths and using the plurality of avoiding flight paths to determine the area.

[0016] By using the information, it can for example be determined if the aircraft can reach a certain point, such as an airport.

[0017] In various embodiments, a point, an area or a space that where the aircraft avoids the missile is provided to the pilot of the aircraft or where an avoiding flight path is provided to the pilot of the aircraft.

[0018] This provides useful information to the pilot.

[0019] In various embodiments, second hypothetical missile that is fired from the hostile platform towards the aircraft as it flies the hypothetical flight path is simulated and used for selecting the avoiding flight path.

[0020] In as second aspect of the invention there is provided a system comprising a missile simulator and an aircraft model the system being configured toa) receive a position of a hostile platform,

[0021] b) receiving a position of the aircraft, and generating and updating a simulated missile, where the missile is simulated as fired from the hostile platform and being headed towards the aircraft, and

[0022] c) repeatedly determining an avoiding flight path (4) that makes the aircraft avoid the missile, by generating a plurality of hypothetical flight paths and selecting an avoiding flight path (4) that makes the aircraft avoid the missile.

[0023] Fig. 1 is a schematic drawing of flight paths in an airspace seen from above, according to some embodiments.

[0024] Fig. 2 is a schematic drawing of a plurality of flight paths in an airspace seen from above, according to some embodiments.

[0025] Fig. 3 shows an example of hardware in a system, according to some embodiments.

[0026] Fig. 4 shows an example of software in a system, according to some embodiments.

[0027] Figs. 5-7 are flow charts showing methods, according to some embodiments.

[0028] DETAILED DESCRIPTION

[0029] As used herein, "course" refers to flight direction of aircraft 1 or missile 3 in the horizontal plane.

[0030] As used herein, "flight direction" refers to the flight direction of the aircraft 1 or the missile 3 in any direction.

[0031] As used herein "position" refers to position in three dimensions, including altitude.As used herein, "speed" and "velocity" relates to speed or velocity in relation to a common frame of reference. Hence air speed or ground speed may be used.

[0032] With reference to Fig. 1, aircraft 1 is flying in the airspace and is threatened by a hostile platform 2 with a known (or assumed) position. The aircraft 1 is preferably a real aircraft, and not a simulated aircraft. Aircraft 1 comprises system 10, comprising missile simulator 11, which simulates that a missile 3 is fired from the hostile platform 2 towards the aircraft 1. The system 10 is configured to simulate how a real missile is fired towards the aircraft 1 using a missile simulator 11 which is configured to generate or initiate a of missile simulation 3, sometimes referred to as "missile 3" or "simulated missile 3" or "missile hypothesis" herein. The missile hypothesis 3 is generated at time point when the aircraft 1 is flying using at least the position of the aircraft 1 and position of hostile platform 2, whereas the missile simulator 11 comprising missile model is previously stored in the system 10. The missile 3 may be simulated as trying to hit the aircraft 1. The missile 3 may be simulated as being headed towards the aircraft, or a hypothetical future position of the aircraft 1. The missile 3 may be simulated as being guided towards the aircraft 1.

[0033] The generation of the missile hypothesis 3 may be triggered in any useful way. In some embodiments the missile hypothesis 3 is initiated by user input, for example if a pilot of aircraft 1 chooses to initiate a missile hypothesis 3. In some embodiments, the missile hypothesis 3 may be initiated automatically. As an example, a missile hypothesis 3 may be initiated when the aircraft 1 comes within a predetermined threshold distance of hostile platform 2. The threshold distance may be selected using information about the action range of known missile models. In some embodiments, a hypothetical missile 3 is triggered (generated) when a predetermined threat threshold is exceeded. The threat level may be determined by using various parameters including, but not limited to: the horizontal distance between the hostile platform 2 and the aircraft 1, the difference in altitude between hostile platform 2 and the aircraft 1 and the velocity of the aircraft 1 in relation to hostile platform 2 and the orientation of the aircraft 1.The aircraft 1 may be any type of aircraft but is preferably a fixed wing aircraft. Aircraft 1 preferably has a pilot. The system 10 comprises an aircraft model 12 which is configured to simulate the flight dynamics of the real aircraft 1. Aircraft 1 is preferably a civilian aircraft, such as a passenger aircraft, such as an airliner.

[0034] Missile 3 may be simulated to terminate when certain conditions are fulfilled, for example when its speed is too low.

[0035] Fig. 1 show positions of aircraft 1 at time points Ti and T2, where time T2 is after Ti. Aircraft 1 flies with a flight direction 14. The position of the missile 3 in relation to aircraft 1 in the horizontal plane is shown in Fig 1, but generally the altitude of the missile 3 is also simulated although not shown in Fig 1 or 2. Missile 3 is fired from hostile platform 2 at Ti or just before Tiand is shown as just having left hostile platform 2. At time T2 missile 3 has moved closer to aircraft 1, and also changed its course slightly.

[0036] The hypothetical missile 3 is generated using at least the position of the aircraft 1. In some embodiments, the direction of travel and the speed of aircraft 1 may be used when generating the hypothetical missile 3. The simulated missile 3 is repeatedly updated. Update may be done with respect to at least missile position, missile orientation and missile velocity.

[0037] The system 10 repeatedly determines at least one point 17 in the airspace that can be safely reached by the aircraft 1. The point 17 may be comprised in an avoiding flight path 4. "Safely" means that the aircraft 1 will avoid the missile 3, for example as determined using the threshold for distance between missile 3 and aircraft 1, as described below.

[0038] In some embodiments an area in the horizontal plane 8, or a space, that can be safely reached by the aircraft 1 is determined, for example by determining a plurality of avoiding flight paths 4. System 10 may be configured to determine a point 17 as far away as possible from the current position of aircraft 1, or a flight path that is a long as possible or an area 8 or space that is as large as possible. An area 8 or space that can be safely reachedmay be determined by interpolating or extrapolating from a plurality of avoiding flight paths 4 that make the aircraft 1 avoid the missile 3.

[0039] In some embodiments the space is determined by first determining an area in the horizontal and then applying a previously stored maximum height and minimum altitude for the aircraft 1.

[0040] In a preferred embodiment, an area 8 in the horizontal plane that can be safely reached by the aircraft 1 is determined. Area 8 may be limited by border line 13. When carrying out second manoeuvre 7 aircraft 1 has limited freedom of manoeuvring, so that is why area 8 is shown as limited by border line 13 in Fig 2, which is where second manoeuvre 7 is to be carried out, at the latest. Hence, the second manoeuvres 7 are not shown in Fig 2 but are included in each avoiding flight path 4.

[0041] The system 10 may repeatedly determine at least one flight path for the aircraft 1 that makes the aircraft 1 avoid the simulated missile 3 (avoiding flight path 4). An example of avoiding fight path 4 at time T1 and an example of an avoiding flight path 4 at time T2 is shown in Fig 1.

[0042] The method may comprise the steps of receiving a position of a hostile platform 2, repeatedly receiving a position of the aircraft 1, and generating and updating a simulated missile 3, where the missile 3 is simulated as fired from the hostile platform and being headed towards the aircraft 1, and repeatedly determining an avoiding flight path 4 that makes the aircraft avoid the missile 3, by generating a plurality of hypothetical flight paths and selecting an avoiding flight path 4 that makes the aircraft 1 avoid the missile. With reference to Fig 7, a method may hence comprise the steps of 300, generating a plurality of hypothetical flight paths and step 301, selecting an avoiding flight path 4, for example by using the distance threshold described below.

[0043] In various embodiments, a plurality of hypothetical flight paths is generated randomly. In some embodiments, the avoiding flight path 4 comprises a first manoeuvre 5 and apredetermined second manoeuvre 7 carried out after the first manoeuvre 5. The method may be carried out by generating a number of first manoeuvres 5 for the aircraft 1 and selecting a time point or position 17 at which the aircraft 1 carries out a predetermined second manoeuvre 7 that makes the aircraft 1 avoid the simulated missile 3. Examples of positions 17 at which the aircraft 1 are to carry out the predetermined second manoeuvre 7 are the end points of first manoeuvres 5 along line 13 in Fig 2.

[0044] In various embodiments, a plurality of first maneuvers 5 are generated randomly. The first maneuvers 5 may be generated using various constraints as described below.

[0045] The first maneuver 5 may be courses in a horizontal plane (constant altitude) or may involve changes in altitude. The first manoeuvre 5 may comprise a turn that makes the aircraft 1 assume a hypothetical straight flight direction 6.

[0046] In a preferred embodiment, the first manoeuvre 5 comprises a course change in the horizontal plane and the second manoeuvre 7 is a course change in the horizontal plane.

[0047] The avoiding flight path 4 may be as flown at constant speed. However, in some embodiments the avoiding flight path 4 involves a change in speed.

[0048] In various embodiments, the first maneuver 5 is carried out at constant speed by aircraft 1. In a preferred embodiment, the first manoeuvres 5 comprises a turn in the horizontal plane, of which Fig 2 is an example.

[0049] In various embodiments, the first maneuver 5 may be a plurality of curved flight paths. The system 10 may then determine where along the curved flight path the aircraft 1 must carry out predetermined second maneuver 7 in order to avoid the missile 3. Hence, in some embodiments, aircraft does not embark on straight flight direction 6, described below.Hence, in various embodiments, system 10 generates a plurality of hypothetical first maneuvers 5 and selects at least one flight path where a second predetermined maneuver 7 carried out after the first maneuver 5, makes the aircraft 1 avoid the simulated missile 3. The avoiding flight paths 4 are selected based on whether the second maneuver 7 makes the aircraft avoid the missile 3.

[0050] The plurality of first maneuvers 5 may be generated by system 10 using various constraints, for example the parameters defining the flight capabilities of aircraft 1. Any useful flight dynamic parameter such as G-force, changes in speed or course or altitude changes may be used to create hypothetical first manoeuvres 5. First maneuvers 5 are preferably maneuvers that are allowed by various flight dynamic parameters of the specific aircraft 1. For example, first maneuvers 5 should not subject the aircraft (or pilot) to G-forces that are not allowed.

[0051] The second manoeuvre 7 is predetermined, meaning that it is defined by at least one predetermined flight dynamic parameter. The predetermined flight dynamic parameter may be a boundary condition for finding the avoiding flight path 4. The flight dynamic parameter may be selected from, for example, G-force, velocity, altitude change, roll rate, side-g, turn radius, or wing loading. Hence the second manoeuvre 7 may be defined by at least one flight dynamic parameter, in particular a threshold value for flight dynamic parameter.

[0052] The parameter is preferably the same for all generated first manoeuvres 5 (hence the second manoeuvre 7 is predefined). In one embodiment, the second manoeuvre 7 is a turn by aircraft 1 in the horizontal plane that subjects the aircraft 1 to a predetermined G force. The turn may be made at constant speed. The magnitude of the second parameter may be selected such that the second manoeuvre 7 does not subject the aircraft 1, pilots and any passengers to uncomfortable or dangerous situations, such as for example too high G forces. For a passenger aircraft, the G force of the second manoeuvre 7 may be, for example, 2.5 Gs, but the magnitude of the parameter that defines the second manoeuvre is selected depending on the type of aircraft.The second manoeuvre 7 may be an evasive manoeuvre. The second manoeuvre 7 is preferably a turn away from the missile 3. In some embodiments, the second manoeuvre 7 may be a turn away from the closest missile 3. The second maneuver 7 may be a course change to the same heading or course as the closest missile 3.

[0053] In some cases, the first manoeuvre 5 is null and the hypothetical course is continuing the current flight direction 14. Hence, in some embodiments, the hypothetical flight direction 6 is the same as the current flight direction 14 of aircraft 1.

[0054] Preferably more than one avoiding flight path 4 is determined, such that 2, 3, 4, 5, 10, or more avoiding flight paths 4 are determined.

[0055] With reference to Fig 2, in a preferred embodiment, the system 10 repeatedly determines a plurality of avoiding flight paths 4 comprising a first maneuver 5 said first maneuver comprising a maneuver part comprising a straight flight direction 6.

[0056] The avoiding flight path 4, may define a time or distance that represents how far the aircraft 1 can continue in a hypothetical flight direction 6 which is obtained after a turn before having to carry out a predetermined second manoeuvre 7 that makes the aircraft 1 avoid the simulated missile 3. The avoiding flight path 4 may define a distance that is traveled by the aircraft 1, before having to carry out the predetermined second maneuver 7, as shown in Fig. 1 and 2. The avoiding flight path 4 may comprise a point 17 in space, for example a point 17 on a horizontal plane at the current altitude of aircraft 1, which defines how far the aircraft 1 can continue in a hypothetical flight direction 6 before having to carry out the second manoeuvre 7. It is referred to the flow chart of Fig. 6, discussed below.

[0057] Fig. 2 shows a plurality of hypothetical first maneuvers 5 (5a, 5b, 5c, 5d, etc), each comprising a turn to assume flight directions 6 (6a, 6b, 6c, 6d, etc). The avoiding flight path 4 defines how far the aircraft 1 can continue in a hypothetical flight direction 6, saidhypothetical flight direction 6 being assumed by the aircraft 1 by carrying out a hypothetical first turn in the horizontal plane, the avoiding flight path 4 being determined by determining, for the hypothetical flight direction 6, a time point or position at which the aircraft carries out a predetermined second manoeuvre 7 that makes the aircraft avoid all of the simulated missiles 3. Second manoeuvre 7 is not shown in Fig 2.

[0058] Hence the plurality of first maneuvers 5 may, in some embodiments, comprises a plurality of different turns by the aircraft 1 in the horizontal plane, such as for example turns towards different flight directions 6 in the horizontal plane. The flight directions 6 in the horizontal plane may be a plurality of flight directions 6 with an angular separation. The angular separation may be a predetermined angular separation, such as for example 10 degrees. The predetermined angular separation may be for example, at most 20 degrees more preferably at most 10 degrees and most preferably at most 5 degrees (such as for example, 5 degree-turn to the right and left (respectively), 10-degree turn to the right and left (respectively), 15-degree turn to the right and left (respectively) etc.). In some embodiments, the angular separation between the flight directions 6 is not predetermined. In some embodiments, the angular separation between flight directions 6 may vary in different subsections of the compass (such a first angular separation for courses up to 90 degrees from the present course, and a second angular separation for courses over 90 degrees from the present course).

[0059] A plurality of avoiding flight paths 4 may be used by system 10 to determine an area 8, preferably a horizontal area 8, or volume, that can be safely reached by aircraft 1, preferably at constant speed. In Fig. 2 the area 8 that can be safely reached is indicated with a thick black line showing border line 13 and thick dashed line. The dashed line indicates that directions 6 and area 8 continue beyond what is shown in the figure. An area 8 may be determined by extrapolating or interpolating from at least two different allowed flight paths 4, and border line 13 is an example of an interpolated border of area 8.

[0060] Several flight directions 6 including flight directions 6a 6b continue indefinitely meaning that the aircraft 1 does not have to carry out second maneuver 7. However, other flightdirections, including flight directions 6c and 6d, are not allowed indefinitely. For flight directions 6c and 6d the aircraft 1 must carry out second maneuver 7 in order to avoid the missile 3. Again, the second maneuver 7 is not shown in Fig 2 but is to be carried out at the latest at point 17 when the aircraft 1 reaches the heavy black line indicating border line 13 in Fig. 2. Hence, the avoiding flight path 4 may extend slightly outside area 8 in Fig 2, however, the aircraft has then committed to carry out predetermined second maneuver 7 and hence its freedom of maneuvering is very limited since the aircraft needs to carry out second maneuver 7. Hence area 8 may be limited by border 13, which shows at which point 17 aircraft 1 must at the latest carry out second maneuver 7. Border line 13 may be determined by interpolating from a plurality of first maneuvers 5. Border line 13 may be determined, for example, by connecting a plurality of points 17 which defines how far aircraft 1 can continue in a hypothetical flight direction 6 before having to carry out the second manoeuvre 7.

[0061] The avoiding flight paths 4 may be determined by generating a plurality of hypothetical flight paths, for example using an aircraft model 12 (described further below) and determining (for example using path selection software 15) which flight paths avoid simulated missile 3 (avoiding flight paths 4). For example, if a hypothetical flight path results in a future position that is within a predetermined threshold distance of a simulated missile 3 the flight path is not allowed and not considered an avoiding flight path 4. The threshold distance may be selected by the skilled person using parameters of the simulated real missile and / or parameters of the aircraft 1. The threshold may be used by path selection software 15. The avoiding flight paths 4 may be determined using forward simulation in time of the system (aircraft and missile) The system 10 may determine when or where in the hypothetical flight path aircraft 1 has to carry out the second manoeuvre 7 in order to avoid the missile 3. For example, the system 10 may determine where along flight direction 6 aircraft 1 has to carry out the second manoeuvre 7 in order to avoid the missile 3. In some cases, such as course 6 at time Ti in Fig 1, the aircraft 1 may continue on the second flight direction 6 indefinitely and still avoid the missile 3 and hence does not have to carry out the second manoeuvre 7 (several such flight directions are shown in Fig. 2).Information that guides a pilot of aircraft 1 along avoiding flight path 4 may be provided to the pilot in any suitable means, for example visual cues or sound cues provided to the pilot. Cues to the pilot may indicate the presence of hostile platform 2 and instruct the pilot to turn in a certain direction or change the altitude. Examples of visual cues include LED lights in the cockpit, or a heads-up display for the pilot. In some embodiments, the information about a safe flight path may be provided to an autopilot.

[0062] In general, a point 17, an area 8 or space that can be safely reached by the aircraft 1 by carrying out first maneuver 5 before having to carry out second maneuver 7 may be determined. The point 17, area 8 or space may be provided to the pilot of aircraft 1 for example on a display 57. In some embodiments, the position of simulated missile 3 may be provided to the pilot on display 57. The point, area or space may overlaid on a map on the display 57.

[0063] In a preferred embodiment, an area 8, preferably a horizontal area 8, that can be reached by the pilot is provided to the pilot. This is convenient to provide to the pilot and is easy for the pilot to grasp in an intuitive manner. Fig 2 is an example of what may be displayed on display 57. In some embodiments, a point, area or space that cannot be reached ("forbidden") may be determined and optionally provided to the pilot, for example on display 57.

[0064] In some embodiments, border line 13 which may correspond to where aircraft 1 has to carry out second maneuver 7 is provided on the display 57.

[0065] The information provided on display 57 aids the pilot in making decisions regarding possible evasive actions. For example, a pilot may use the displayed information to make a decision about whether it is possible to reach approach point 9 of an airport in order to land the aircraft 1 safely. In Fig. 2 the approach point 9 is within area 8 and can be safely reached by aircraft 1. Without the information provided to the pilot in Fig. 2 it may seem not very feasible for pilot to reach approach point 9 safely because it involves a course towards the hostile platform 2.In Figs 1 and 2, the first maneuver 5 and second maneuver 7 are maneuvers that does not alter the altitude of aircraft 1. However, in some embodiments, first or second maneuvers 5, 7 may involve an altitude change of aircraft 1. In general, parameters for the first and second maneuver 5,7 may include any suitable flight parameter such as G-force, speed change, course change or altitude change. The first or second maneuver 5, 7 may be defined by more than one predefined parameter, such as change in flight direction and speed or change in course and altitude.

[0066] The system 10 repeatedly, for example at times Ti, T2, etcetera, generates avoiding flight paths 4 given the position of the aircraft 1 and the positions of the simulated missile 3. This provides an updated scenario to the pilot of the aircraft 1.

[0067] The system 10 should allow for some decision and reaction time of the pilot and possible reaction time of the controls of the aircraft 1 (such as fly-by-wire system of aircraft 1). It may, for example, be assumed that the first manoeuvre 5 is carried out immediately, or at a predetermined time which may be within from 0 to 5 seconds, more preferably from 0.25 seconds to 3 seconds of generating the scenario.

[0068] Fig. 3 shows various hardware components of system 10. System 10 may be located in aircraft 1. System may comprise memory 50, processor 51, bus 52, and input interface 53. System 10 may receive a position of the hostile platform 2 from an external source 59, such as an airborne or land-based sensor, and provided to the system 10 wirelessly. System 10 may comprise means for wireless communication, including antenna 58 for example communication with an external source 59, such as a ground-based sensor. Alternatively, system 10 may receive position of a hostile platform from a sensor 55, such as radar on board aircraft 1. In some embodiments, position of hostile platform is provided to system 10 as data describing a geographical position, which may be received from an external source 59 wireless communication means. The wireless communication means may comprise a radio data link and antenna 58. The wireless communication means may comprise suitable software, such as communication software 18, for supporting a radio datalink. Suitable protocols include CPDLC (Controller-Pilot Data Link Communications) and FANS (Future Air Navigation System) and similar technologies.

[0069] Aircraft 1 has a navigation system 56 that determines the position of aircraft 1 and provides it to other components of system 10. The position is provided repeatedly in order to provide an updated position of aircraft 1 to system 10. The navigation system 56 may for example comprise a GPS receiver, gyroscopes and the like. System 10 may comprise display 57 arranged to provide information to the pilot of the aircraft 1.

[0070] Fig. 4 shows various software components of system 10. The system 10 comprises navigation data 14, which may comprise position of aircraft 1 and position of hostile platform 2. Navigation data 14 is provided with from sensor 55, navigation system 56, or external source 59.

[0071] Missile simulator 11 is configured to generate, store and update data for a simulated missile 3, also referred to as "missile hypothesis" in Fig 4. Missile simulator 11 comprises a missile model. Missile models are known by the skilled person. A missile model uses parameters from a real missile type in order to model the behavior of the real missile. The missile model may for example comprise information that simulates the flight characteristics, flight time and guidance system of the real missile. The state (position, velocity, orientation, energy) of the missile 3 may be updated with a predetermined interval.

[0072] The missile 3 is simulated as having its own propulsion system and steering system. The missile 3 may be simulated as having a guidance system, which may comprise a homing sensor of the missile. Missile 3 may change its course or altitude during simulated flight. The missile model uses the position of the aircraft 1, and optionally the velocity of aircraft 1, as input when generating and updating the missile 3.

[0073] The missile 3 may be simulated as a guided surface-to-air missile or an air-to-air missile. The missile simulator 11 will simulate how a real missile changes flight direction for example ifthe aircraft 1 takes evasive action. Hence, the missile model may use an updated position of aircraft 1.

[0074] The missile model may use the known position (as determined by navigation system 56) of aircraft 1 as input for simulating the guidance of the simulated missile 3. The missile simulation 3 simulates how a real missile would be guided towards the aircraft 1. Typically, the aircraft 1 is constantly moving and the missile 3 is simulated to steer towards the position (or hypothetical future position) of the aircraft 1 in order to hit aircraft 1. This may be done as the position of the aircraft 1 and the simulated missile is repeatedly updated. Hence, if the aircraft 1 changes course, altitude or speed, the missile simulation 3 will be updated to steer towards the aircraft 1 as to intercept the aircraft 1.

[0075] The position, velocity and optionally orientation and optionally energy of the missile hypothesis 3 may be updated with at least a predetermined interval. The predetermined time interval may be less than 10 s preferably less than 3 seconds and preferably less than every second. The position of the aircraft 1 may be provided to the missile simulator 11 with any useful frequency.

[0076] System 10 moreover comprises an aircraft model 12 that is arranged to simulate the flight dynamics of the aircraft 1. The aircraft model 12 is adapted to the specific properties of the real aircraft 1 in question with regard to flight dynamics characteristics, such as allowed speed, turn radius, G-forces, acceleration, max altitude etc. The aircraft model 12 is configured to generate, store and update data for flight paths. The flight paths are provided to path selection software 15, which selects avoiding flight paths 4. Path display software 16 may be arranged to receive data from path selection software 15 and provide data to display 57, in order to display avoiding flights paths or areas 8 or points 17.

[0077] Position and velocity of aircraft 1 as determined by navigation system 56 is preferably used as input when generating and updating the missile simulation 3, in particular the position and velocity of aircraft 1 at the time of firing of the missile 3.After initiation of the missile simulation 3, navigation system 56 provides information about the position and optionally velocity of the aircraft 1 to the missile simulator 11 in order to update the missile simulation 3.

[0078] The missile simulator 11 may be arranged to receive data from the sensor 55 of the aircraft 1. Sensor 55 may provide updated data to simulator 11 at a predetermined frequency, which may be, for example, at least once every second.

[0079] In the example of Fig. 1, hostile platform 2 has a fixed position. However, in some embodiments, hostile platform 2 may be moving. The position and the altitude of the hostile platform 2 may be determined using conventional means such as for example sensor 55. The position of the hostile platform 2 may be updated as required.

[0080] With reference to Fig 5, a method may comprise the steps of 100 receiving the position of a hostile platform 2. In step 101 a missile simulation 3 is generated. In step 102 the missile simulation 3 is updated, in particular using the position of the aircraft 1. It is assumed that the missile 3 is heading towards the position of the aircraft 1. Hence, when the position of the aircraft 1 is updated, the heading of the missile 3 will be updated to head towards the aircraft 1 (or the future position of the aircraft 1). In some embodiments, the missile 3 is simulated as heading towards a future position of the aircraft 1, given hypothetical flight paths. In some embodiments, it is assumed that the hypothetical missile 3 is headed towards a future position of the aircraft 1.

[0081] With reference to Fig. 6, a method may comprise the steps of 200: receiving position of hostile platform 2 and position of aircraft 1. In step 201 the missile simulation is initiated and updated. Steps 200 and 201 are carried out as in Fig. 5. In step 202, at least one point 17, in the airspace, preferably an area in the horizontal plane, or a space, that can be safely reached by the aircraft 1 is determined, for example by determining avoiding flight paths.In some embodiments, a plurality of missiles 3 are generated. A flight path that makes the aircraft 1 avoid all of the simulated missiles 3 may then be determined. In some embodiments, a second hypothetical future missile is generated based on a hypothetical position of aircraft 1 at a future time point where the hypothetical position is a part of an avoiding flight path 4. Hence, in various embodiments, system 10 may simulate a missile 3 that is fired towards the aircraft 1 in the future. The system 10 may for example assume that aircraft 1 carries out a first maneuver 5 and the generate a second missile 3 based on future positions of aircraft 1 during the first maneuver 5. Avoiding flight paths 4 are then selected based on if first and second missiles 3 are avoided during flight path. The system 10 may select flight paths that makes the aircraft avoid future missiles 3. The system 10 may generate a plurality of flight paths, generate hypothetical missiles 3 for those flight paths, and select those flight paths that avoid all missiles 3.

[0082] In some embodiments, the method is carried out aboard aircraft 1. However, in some embodiments the method is carried out on a surface based site, such as an air control facility. The system 10 is, hence, in some embodiments, not located on aircraft 1.

[0083] It is understood that the present methods and system is partly computer-implemented, using digital computer equipment. The various embodiments and components described herein and communication between these components uses digital computer technology for storing and handling digital information and signals as well as suitable hardware and software, including for example suitable digital processors, digital memories, input means, output means, buses and communications interfaces. A user may be able to make input using for example a keyboard, a mouse or a touch screen. Output may be provided on for example a display 57.

[0084] The methods herein can be implemented with any suitable combination of software and hardware. The system 10 may comprise an operating system. Any suitable programming language may be used for the software units and methods described. Data communication may be wireless, or wire bound. For example, an Apple iPad or other tablet computer is a useful device because it has a large screen and can easily be used by a pilot sitting in thecockpit. System 10 may use, and integrate toward, standard hardware and software in an aircraft 1 such as, for example, computer systems, communication systems, navigation systems and information display systems.

[0085] 5 It is realized that everything which has been described in connection to one embodiment is fully applicable to other embodiments, as compatible. Hence, the invention is not limited to the described embodiments, but can be varied within the scope of the enclosed claims. While the invention has been described with reference to specific exemplary embodiments, the description is in general only intended to illustrate the inventive concept and should not w be taken as limiting the scope of the invention. The invention is generally defined by the claims.

Claims

CLAIMS1. A method involving an aircraft in an airspace, the method comprising, a) receiving a position of a hostile platform,b) receiving a position of the aircraft, and generating and repeatedly updating a simulated missile, where the missile is simulated as fired from the hostile platform and being headed towards the aircraft, andc) repeatedly determining an avoiding flight path (4) that makes the aircraft avoid the missile, by generating a plurality of hypothetical flight paths and selecting an avoiding flight path (4) that makes the aircraft avoid the missile.

2. The method of claim 1 where the avoiding flight path comprises a first manoeuvre (5) and a predetermined second manoeuvre (7) carried out after the first manoeuvre.

3. The method according to claims 2 where step c) is carried out by generating a number of first manoeuvres (5) for the aircraft and time point or position at which the aircraft carries out a predetermined second manoeuvre (7) that makes the aircraft avoid the simulated missile.

4. The method of any of claims to 2 to 3 where the predetermined second manoeuvre (7) is defined by at least one predetermined flight dynamic parameter.

5. The method according to claim 3 where the first manoeuvre (5) comprises a turn in the horizontal plane that makes the aircraft assume a straight flight direction (6), the avoiding flight path 4 being determined by determining, for the flight direction (6), a time point or position at which the aircraft carries out a predetermined second manoeuvre (7) that makes the aircraft avoid the simulated missile.

6. The method of claim 4 or 5 where the predetermined second manoeuvre is a turn in the horizontal plane that subjects the aircraft to a predetermined G- force.

7. The method of any one of claims 1 to 6 where a plurality of avoiding flight paths (4) is determined.

8. The method of claim 7 where a space or an area in the horizontal plane where the aircraft avoids the missile is determined by determining a plurality of avoiding flight paths (4) and using the plurality of avoiding flight paths (4) to determine the area or the space.

9. The method of any one of claims 1 to 8 where a point (17), an area (8) or a space where the aircraft avoids the missile is provided to the pilot of the aircraft or where an avoiding flight path (4) is provided to the pilot of the aircraft.

10. A system (10) comprising a missile simulator (11) and an aircraft model (12) the system being configured toa) receive a position of a hostile platform,b) receiving a position of the aircraft, and generating and repeatedly updating a simulated missile, where the missile is simulated as fired from the hostile platform and being headed towards the aircraft, andc) repeatedly determining an avoiding flight path (4) that makes the aircraft avoid the missile, by generating a plurality of hypothetical flight paths and selecting an avoiding flight path (4) that makes the aircraft avoid the missile.

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